WO2022210874A1 - Mold and method for manufacturing hot-press molded article - Google Patents

Mold and method for manufacturing hot-press molded article Download PDF

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Publication number
WO2022210874A1
WO2022210874A1 PCT/JP2022/015965 JP2022015965W WO2022210874A1 WO 2022210874 A1 WO2022210874 A1 WO 2022210874A1 JP 2022015965 W JP2022015965 W JP 2022015965W WO 2022210874 A1 WO2022210874 A1 WO 2022210874A1
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WIPO (PCT)
Prior art keywords
width
rib portion
mold
hot press
slow cooling
Prior art date
Application number
PCT/JP2022/015965
Other languages
French (fr)
Japanese (ja)
Inventor
皓大 村澤
真吾 藤中
Original Assignee
日本製鉄株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 日本製鉄株式会社 filed Critical 日本製鉄株式会社
Priority to CN202280024788.2A priority Critical patent/CN117177825A/en
Priority to JP2023511480A priority patent/JP7477809B2/en
Priority to KR1020237035493A priority patent/KR20230158086A/en
Publication of WO2022210874A1 publication Critical patent/WO2022210874A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
    • B21D22/20—Deep-drawing
    • B21D22/208—Deep-drawing by heating the blank or deep-drawing associated with heat treatment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
    • B21D22/02—Stamping using rigid devices or tools
    • B21D22/022—Stamping using rigid devices or tools by heating the blank or stamping associated with heat treatment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
    • B21D22/20—Deep-drawing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D24/00—Special deep-drawing arrangements in, or in connection with, presses
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D24/00—Special deep-drawing arrangements in, or in connection with, presses
    • B21D24/005—Multi-stage presses

Definitions

  • the present disclosure relates to a mold and a method for manufacturing a hot press-formed product using the mold.
  • hot press forming the material is heated to a temperature range where the microstructure becomes an austenite single phase. Then, the heated raw material is hot press-molded using a hot press device equipped with a mold. In hot press molding, the material is softened by heating. Therefore, the press formability of the material in hot press forming is high. In hot press forming, the material being hot pressed also contacts substantially the entire forming surface of the mold. At this time, the material is quenched by removing heat from the metal mold that is in contact with the material. Thus, in hot press forming, the material is hot press formed and quenched at the same time. Therefore, hot press-molding can easily produce a high-strength hot-press-molded product.
  • a heated material is hot press molded using a mold.
  • the material is partially quenched by flowing a coolant through part of the gap between the mold and the material.
  • the mold of Patent Document 1 has a supply port on the surface of the mold for supplying the coolant in the coolant passage inside the mold to the outside of the mold.
  • the mold of Patent Document 1 further includes a convex portion that contacts a boundary region between the high-strength portion and the low-strength portion of the material.
  • a coolant is supplied from the supply port to the gap between the high-strength portion and the mold.
  • the coolant is not supplied to the gap between the low-strength portion and the mold.
  • a hot press-formed product having a low-strength portion with excellent shock absorption ability can be manufactured.
  • a hot press-formed product having excellent impact absorption ability may be produced by other techniques different from the technique described in Patent Document 1.
  • An object of the present disclosure is to provide a mold capable of producing a hot press-formed product having excellent impact absorption ability by hot press molding, and a method for producing a hot press-formed product using the mold. That is.
  • a mold according to the present disclosure is a mold for performing hot press molding on a material.
  • the mold includes an upper mold and a lower mold.
  • the upper mold has a first molding surface.
  • the lower mold has a second molding surface.
  • the second molding surface is arranged to face the first molding surface during hot press molding, and together with the first molding surface hot press mold the material.
  • the first molding surface includes a first slow cooling region.
  • the first slow cooling region has a plurality of first ribs and a plurality of first grooves.
  • the plurality of first rib portions are arranged in the width direction of the first rib portion.
  • the plurality of first grooves are arranged in the width direction of the first grooves.
  • the first rib is formed between adjacent first grooves.
  • the width of the first rib portion is narrower than the width of the first groove portion.
  • the second molding surface includes a second slow cooling region.
  • the second slow cooling region has a plurality of second rib portions and a plurality of second groove portions.
  • the plurality of second rib portions are arranged in the width direction of the second rib portions.
  • the plurality of second grooves are arranged in the width direction of the second grooves.
  • the second rib is formed between adjacent second grooves.
  • the width of the second rib portion is narrower than the width of the second groove portion.
  • the method for manufacturing a hot press-formed product includes the steps of preparing a material, heating the prepared material to a temperature of A c 3 or more, and applying the heated material with the above-described mold. It comprises a step of performing hot press molding, and a step of releasing the hot press-molded material from the mold to produce a hot press-molded product.
  • a mold according to the present disclosure can produce a hot press-formed product having excellent impact absorption capability by hot press-forming.
  • the method for producing a hot press-formed product according to the present disclosure can produce a hot press-formed product having excellent impact absorption capacity.
  • FIG. 1 is a front view showing an example of a hot press device for hot press molding.
  • FIG. 2 is a perspective view showing an example of the mold according to this embodiment.
  • FIG. 3 is a cross-sectional view showing the state of the mold and material during hot press molding in the slow cooling region of an example of the mold according to the present embodiment.
  • FIG. 4 is a cross-sectional view showing the state of the mold and the material during hot press molding in the quench region of an example of the mold according to this embodiment.
  • FIG. 5A is an enlarged schematic diagram of region 100 in FIG.
  • FIG. 5B is a schematic diagram of FIG. 5A excluding material B, showing the time of hot press molding.
  • FIG. 5A is an enlarged schematic diagram of region 100 in FIG.
  • FIG. 5B is a schematic diagram of FIG. 5A excluding material B, showing the time of hot press molding.
  • FIG. 5C is a cross-sectional view perpendicular to the extending direction of the first rib portion or the second rib portion having a shape different from that of FIGS. 5A and 5B.
  • FIG. 5D is a cross-sectional view perpendicular to the extending direction of the first rib portion or the second rib portion having a shape different from that of FIGS. 5A to 5C.
  • FIG. 6 is a schematic diagram of the region 100 of FIG. 3 as viewed from above (the normal direction of the first slow cooling region and the second slow cooling region).
  • FIG. 7 is a schematic diagram enlarging the region 200 in FIG. FIG.
  • FIG. 8 is a diagram showing the relationship between Fn1 and the temperature variation ⁇ T (° C.) in the first slow cooling region and the second slow cooling region.
  • FIG. 9 is a schematic diagram of the heat conduction model used in the two-dimensional heat transfer simulation for creating FIG.
  • FIG. 10 is a diagram showing the relationship between Fn2 and the cooling rate V (°C/sec) of material B during hot press molding.
  • FIG. 11 is a perspective view showing another example different from FIG. 2 of the mold according to this embodiment.
  • FIG. 12 is a perspective view showing another example of the mold according to this embodiment, which is different from FIGS. 2 and 11.
  • FIG. 13 is a perspective view showing another example different from FIGS. 2, 11 and 12 of the mold according to this embodiment.
  • FIG. 14 is another example different from FIG.
  • FIG. 5A among schematic diagrams in which the region 100 in FIG. 3 is enlarged.
  • 15 is a cross-sectional view taken along the line segment XV-XV in FIG. 14.
  • FIG. FIG. 16 is another example different from FIGS. 5A and 14 in a schematic diagram in which the region 100 in FIG. 3 is enlarged.
  • FIG. 17 is a schematic diagram showing only the rib portion when viewing the region 100 of FIG. 16 from the normal direction of the first slow cooling region.
  • FIG. 18 is another example different from FIGS. 5A, 14, and 16 in the enlarged schematic diagram of the region 100 in FIG.
  • FIG. 19 is a schematic diagram showing only the rib portion when viewing the region 100 of FIG. 18 from the normal direction of the first slow cooling region.
  • impact absorption members are required to have improved impact energy absorption capacity at the time of a collision, that is, improved impact absorption capacity.
  • Impact energy is absorbed by plastic deformation of the structural member. Therefore, in order to improve the impact absorption ability, it is effective to exhibit excellent plastic deformation ability even when subjected to high stress.
  • the present inventors thought that if the cooling rate of the material during hot press molding could be reduced, the material would be able to exhibit excellent plastic deformability even when subjected to high stress. Therefore, the present inventors investigated the surface shape of the molding surface of the mold. As a result, the present inventors considered that the cooling rate of the material during hot press-forming can be reduced by forming a slow-cooling region including a plurality of ribs and a plurality of grooves on the molding surface.
  • the rib portion extends in a predetermined direction, and has a convex cross section perpendicular to the extending direction.
  • the groove extends along the extending direction of the rib, and has a concave cross section perpendicular to the extending direction. The plurality of rib portions and the plurality of groove portions are alternately formed.
  • the rib part directly contacts the material in the slow cooling region to remove heat from the material.
  • the groove does not come into direct contact with the material. Therefore, if the molding surface includes a plurality of ribs and a plurality of grooves, it is possible to reduce the contact area between the mold and the material during hot press molding. Therefore, the cooling rate of the material during quenching can be reduced.
  • the present inventors focused on the width of the rib and the width of the groove among the plurality of ribs and the plurality of grooves in the slow cooling region of the molding surface of the mold, and further examined in detail. As a result, the present inventors have found that if the width of the rib portion is narrower than the width of the groove portion, heat dissipation from the material during hot press forming can be effectively reduced, and the cooling rate can be reduced. If the cooling rate of the material during hot press molding can be slowed down, the increase in strength of the material can be suppressed, and the impact absorption capacity can be enhanced.
  • the width of the rib portion in the slow cooling region narrower than the width of the groove portion, it is possible to form an impact buffering region with reduced strength in at least a portion of the hot press-formed product.
  • the width of the rib portion is narrower than the width of the groove portion, wavy deformation occurs on the surface of the hot press-formed product, which may reduce the dimensional accuracy of the hot press-formed product. Therefore, the present inventors investigated the cause of this. As a result, the present inventors obtained the following findings.
  • the ribs formed in the slow cooling region of the molding surface of one of the pair of molds cool the molding surface of the other mold. It may enter the groove formed in the region. In this case, the above-described wavy deformation occurs on the surface of the hot press-formed product.
  • the present inventors have found that during hot press molding, the rib portion formed in the slow cooling region of one mold and the rib portion formed in the slow cooling region of the other mold and overlap when viewed from the normal direction of the slow cooling region. If at least a part of the rib formed in the slow cooling region of one mold overlaps with the rib formed in the slow cooling region of the other mold, the rib can be prevented from entering the groove. can be suppressed.
  • the rib portion formed in one slow cooling region and the other slow cooling region At least a part overlaps with the formed rib portion.
  • the mold according to the present embodiment completed based on the above knowledge and the method for manufacturing a hot press-formed product using the mold according to the present embodiment have the following configurations.
  • a mold for performing hot press molding on a material an upper mold having a first molding surface; a lower mold having a second molding surface that is arranged to face the first molding surface and hot press molds the material together with the first molding surface during hot press molding;
  • the first molding surface is including a first slow cooling region having a plurality of first ribs and a plurality of first grooves;
  • the plurality of first rib portions are arranged in the width direction of the first rib portion,
  • the plurality of first grooves are arranged in the width direction of the first grooves,
  • the first rib portion is formed between the adjacent first groove portions,
  • the width of the first rib portion is narrower than the width of the first groove portion,
  • the second molding surface is including a second slow cooling region having a plurality of second ribs and a plurality of second grooves;
  • the plurality of second rib portions are arranged in the width direction of the second rib portion,
  • the plurality of second grooves are arranged in the width direction of the second
  • the mold of [1] can produce a hot press-formed product with excellent impact absorption capability by hot press-forming.
  • the mold of [2] can improve the accuracy of the simulation of heat transfer in the material during hot press molding.
  • the width of the first rib portion is 10 to 50% of the width of the first groove portion
  • the width of the second rib portion is 10 to 50% of the width of the second groove portion
  • the cooling rate can be slowed during hot press molding. If the cooling rate can be slowed down, it becomes easier to stop cooling at a desired material temperature. For example, during hot press forming, cooling is stopped between the Mf point and the Ms point, and then the heating and holding step described later is performed to generate martensite and retained austenite in the microstructure of the material. You can adjust the amount. Further, for example, during hot press molding, cooling is stopped at a temperature between Ms point and 500 ° C., and then a heating and holding step described later is performed, so that the microstructure of the material is mainly bainite. It can be an organization.
  • the mold of [4] can suppress the temperature variation of the material during hot press molding.
  • the width of the first rib portion is 10 to 50% of the width of the first groove portion
  • the width of the second rib portion is 10 to 50% of the width of the second groove portion
  • the width of each of the first rib portion and the second rib portion is 1.0 to 8.0 mm
  • Each height of the first rib portion and the second rib portion is 0.2 to 5.0 mm
  • Fn1 defined by formula (1) is 14 or less
  • Fn1 Wr0.9 / P00.8 +0.05Hr (1)
  • Wr in the formula (1) is the width (mm) of the first rib portion and the second rib portion
  • P0 Wr/Ws
  • Ws is the width of the first groove portion and the second groove portion.
  • Hr is the height (mm) of the first rib portion and the second rib portion.
  • the mold of [5] can further suppress the temperature variation of the material during hot press molding.
  • the width of the first rib portion is 10 to 50% of the width of the first groove portion
  • the width of the second rib portion is 10 to 50% of the width of the second groove portion
  • the width of each of the first rib portion and the second rib portion is 1.0 to 8.0 mm
  • Each height of the first rib portion and the second rib portion is 0.2 to 5.0 mm
  • Fn2 defined by formula (2) is 30 or more, Mold.
  • Ws in the formula (2) is the width (mm) of the first groove portion and the second groove portion
  • Wr is the width (mm) of the first rib portion and the second rib portion
  • Hr is the height (mm) of the first rib portion and the second rib portion.
  • the cooling speed of the material can be made slower. If the cooling rate can be slowed down, it becomes easier to stop cooling at the desired material temperature. For example, during hot press forming, cooling is stopped between the Mf point and the Ms point, and then the heating and holding step described later is performed to generate martensite and retained austenite in the microstructure of the material. You can adjust the amount. Further, for example, during hot press molding, cooling is stopped at a temperature between Ms point and 500 ° C., and then a heating and holding step described later is performed, so that the microstructure of the material is mainly bainite. It can be an organization.
  • the mold of [7] can further suppress the temperature variation of the material during hot press molding.
  • a method for manufacturing a hot press-formed product a process of preparing materials; heating the prepared material to a temperature of A c 3 or higher; A step of performing hot press molding on the heated material using the mold according to any one of [1] to [7]; A step of releasing the hot press-formed material from the mold to produce a hot press-formed product; A method for producing a hot press-formed product.
  • the method for producing a hot press-formed product in [8] can produce a hot press-formed product with excellent impact absorption capability.
  • FIG. 1 is a front view showing an example of a hot press machine 1 for hot press molding.
  • a hot press machine 1 has substantially the same configuration as a known hot press machine, except for a mold 10 according to this embodiment.
  • a hot press device 1 includes a frame 2, a slide 3, a bolster 4, and a die 10 (upper die 11 and lower die 12).
  • the vertical (vertical) direction of the hot press machine 1 is also called the V direction
  • the width direction of the hot press machine 1 is also called the W direction
  • the V direction and the direction perpendicular to the W direction are also called the L direction.
  • the frame 2 is arranged on the upper part of the hot press device 1.
  • the frame 2 supports a slide 3 arranged below the frame 2 so as to be able to move up and down.
  • the frame 2 has a drive (not shown) for raising and lowering the slide 3 .
  • the drive may be a mechanical mechanism or a hydraulic mechanism.
  • the slide 3 is attached to the frame 2 and can be vertically moved by a driving device provided in the frame 2 .
  • An upper die 11 is attached to the lower surface of the slide 3 .
  • a bolster 4 is arranged below the slide 3 .
  • the upper surface of bolster 4 faces the lower surface of slide 3 .
  • a lower mold 12 is attached to the upper surface of the bolster 4 . At this time, the lower mold 12 is arranged below the upper mold 11 .
  • the mold 10 includes the upper mold 11 described above and the lower mold 12 described above.
  • the upper die 11 and the lower die 12 extend in the L direction in FIG.
  • the direction in which the upper die 11 and the lower die 12 extend is also referred to as "longitudinal direction (L direction) of the die 10".
  • L direction and the direction perpendicular to the V direction in FIG. 1 are also referred to as the "width direction (W direction) of the mold 10".
  • the upper mold 11 is fixed to the lower surface of the slide 3 and the lower mold 12 is fixed to the upper surface of the bolster 4 .
  • the lower mold 12 is arranged below the upper mold 11 .
  • a heated material blade
  • the upper die 11 slides in the V direction relative to the lower die 12 and applies an external force to the material while being in contact with the material.
  • the upper mold 11 and the lower mold 12 hot press mold the material. Thereby, the material is formed into a desired shape.
  • the molding surface of the upper mold 11 and the molding surface of the lower mold 12 come into contact with the material, and the upper mold 11 and the lower mold 12 remove heat from the material and harden it. Therefore, a hot press-formed product having a desired shape and enhanced strength is manufactured.
  • the hot press device 1 may include a configuration not shown in FIG.
  • the hot press device 1 may include, for example, a cooling device for cooling the mold 10 .
  • a flow path through which the cooling medium passes is provided inside the mold 10 .
  • a pump for supplying a cooling medium inside the mold 10 is arranged.
  • the hot press device 1 may further include a transport mechanism for transporting the material to the hot press device 1 .
  • the hot press device 1 may have a configuration not shown in FIG. 1, which is provided in a known hot press device.
  • FIG. 2 is a perspective view of the mold 10 in FIG. 1.
  • upper mold 11 has first molding surface 110 .
  • the first molding surface 110 is arranged on the lower surface of the upper mold 11 .
  • the first molding surface 110 includes a concave portion extending in the L direction in the central portion in the W direction.
  • the lower mold 12 has a second molding surface 120.
  • the second molding surface 120 is arranged on the upper surface of the lower mold 12 .
  • the second molding surface 120 includes a convex portion extending in the L direction at the central portion in the W direction.
  • the second molding surface 120 is arranged to face the first molding surface 110 .
  • the second molding surface 120 and the first molding surface 110 are brought into contact with the material (blank) to hot press mold the material.
  • the first molding surface 110 includes a first slow cooling region 113 indicated by hatching.
  • the first slow cooling region 113 is formed on a portion of the first molding surface 110 .
  • first forming surface 110 includes first slow cooling region 113 and first quenching region 114 .
  • the second molding surface 120 includes a second slow cooling region 123 indicated by hatching.
  • the second slow cooling region 123 is formed on a portion of the second molding surface 120 .
  • second molding surface 120 includes second slow cooling region 123 and second quenching region 124 .
  • the first quench zone 114 faces the second quench zone 124 .
  • the first rapid cooling region 114 and the second rapid cooling region 124 form high-strength regions having high strength in the material (hot press-formed product) after hot press-forming.
  • the first slow cooling region 113 faces the second slow cooling region 123 .
  • the first slow-cooling region 113 and the second slow-cooling region 123 are impact-absorbing regions that have a lower strength than the high-strength region and are prone to plastic deformation in the material (hot press-formed product) after hot press forming. Form.
  • FIG. 3 is a cross-sectional view including the V direction and the W direction showing the state of the mold 10 and the material (blank) B in the first slow cooling region 113 and the second slow cooling region 123 during hot press molding.
  • FIG. 4 is a cross-sectional view including the V direction and the W direction showing the state of the mold 10 and the material B in the first quenching region 114 and the second quenching region 124 during hot press molding.
  • 3 and 4 show the state in which the upper mold 11 reaches the bottom dead center and the mold 10 is closed.
  • FIGS. 3 and 4 show that substantially the entire first molding surface 110 of the upper mold 11 and substantially the entire second molding surface 120 of the lower mold 12 are in contact with the material B, and are attached to the material B. It shows the state in which an external force is applied.
  • material B is sandwiched between upper mold 11 and lower mold 12 during hot press molding. At this time, the concave portion of the first molding surface 110 fits into the convex portion of the second molding surface 120 . As a result, the material B is formed into a hat-shaped hot press-formed product.
  • the mold 10 of FIG. 2 further includes slow cooling regions (113 and 123) and rapid cooling regions (114 and 124).
  • the surface structure of the first slow cooling region 113 forming the impact buffering region of the hot press-formed product is the same as that of the first rapid cooling region forming the high-strength region of the hot press-formed product.
  • 114 surface structure On the second molding surface 120 of the lower die 12, the surface structure of the second slow-cooling region 123 forming the impact buffering region of the hot press-formed product is different from that of the second slow cooling region 123 forming the high-strength region of the hot press-formed product. 2 different from the surface structure of the quench zone 124;
  • the surface structures of the first molding surface 110 and the second molding surface 120 are further described below.
  • first molding surface 110 [Configuration of first slow cooling region 113]
  • 5A is an enlarged view of the region 100 within the first slow cooling region 113 of the first molding surface 110 in FIG. 3.
  • FIG. 5A first slow cooling region 113 of first molding surface 110 of upper mold 11 has a plurality of first rib portions 111 and a plurality of first groove portions 112 .
  • FIG. 6 is a schematic diagram of the region 100 of FIG. 3 as viewed from above (the normal direction of the first slow cooling region 113 and the second slow cooling region 123).
  • the plurality of first rib portions 111 extend in a predetermined direction. In FIGS. 5A and 6, as an example, the multiple first rib portions 111 extend in the L direction. However, the extending direction of the plurality of first rib portions 111 is not limited to the L direction.
  • the plurality of first rib portions 111 are arranged in the width direction of the first rib portions 111 .
  • the width direction of the first rib portion 111 is a direction perpendicular to the extending direction of the first rib portion 111 .
  • the width direction of the first rib portion 111 is the W direction.
  • the width direction of the first rib portion 111 is not limited to the W direction.
  • each first rib portion 111 extends in the L direction and is arranged in the W direction.
  • the plurality of first grooves 112 are arranged in the width direction of the first grooves 112, and the first ribs 111 are formed between adjacent first grooves 112. As shown in FIG. In FIG. 5A, the first grooves 112 extend in the L direction and are arranged in the W direction, like the first ribs 111 . Furthermore, the first rib portion 111 is formed between two adjacent first groove portions 112 . 5A, the plurality of first grooves 112 and the plurality of first ribs 111 both extend in the L direction, and the first grooves 112 and the first ribs 111 are alternately arranged in the W direction.
  • the width of first rib portion 111 is narrower than the width of first groove portion 112 .
  • the width of the first rib portion 111 means the width of the first rib portion 111 in a cross section perpendicular to the extending direction of the first rib portion 111 .
  • the width of the first rib portion 111 means the width of the first rib portion 111 in the W direction.
  • the width of the first groove portion 112 means the width of the first groove portion 112 in a cross section perpendicular to the extending direction of the first groove portion 112 .
  • the width of the first groove portion 112 means the width of the first groove portion 112 in the W direction.
  • the width of the first rib portion 111 and the width of the first groove portion 112 can be easily determined using, for example, vernier calipers.
  • the width of first rib portion 111 is narrower than the width of first groove portion 112 .
  • the heat removal amount in the first groove portion 112 is smaller than the heat removal amount in the first rib portion 111 . Since the width of the first rib portion 111 is narrower than the width of the first groove portion 112, the amount of heat removal in the first rib portion 111 can be reduced. Therefore, in the first slow cooling region 113 , the cooling rate of the material B can be made slower than in the first rapid cooling region 114 .
  • the degree of quenching of the region of the material B that is in contact with the first slow cooling region 113 can be reduced.
  • the material B (hot press-formed product) after hot press-forming can be formed with a shock absorbing region with reduced strength.
  • FIG. 7 is an enlarged view of area 200 in first quench zone 114 of first forming surface 110 of FIG.
  • first rib portion 111 and first groove portion 112 are not formed in first rapid cooling region 114 of first molding surface 110 of upper mold 11 .
  • the first quench region 114 of the first molding surface 110 is a smooth surface. Therefore, substantially the entire first quench region 114 is in contact with the material B during hot press forming. Therefore, in the first rapid cooling region 114 , the cooling rate of the material B can be made faster than in the first slow cooling region 113 .
  • the degree of quenching of the area of the material B that is in contact with the first rapid cooling area 114 can be increased. As a result, it is possible to form a high-strength region having a higher strength than the impact buffer region in the material B (hot press-formed product) after hot press-forming.
  • second slow cooling region 123 of second molding surface 120 of lower die 12 has a plurality of second rib portions 121 and a plurality of second groove portions 122 .
  • the plurality of second rib portions 121 extend in a predetermined direction.
  • the plurality of second rib portions 121 extend in the L direction.
  • the extending direction of the plurality of second rib portions 121 is not limited to the L direction.
  • the plurality of second rib portions 121 are arranged in the width direction of the second rib portions 121 .
  • the width direction of the second rib portion 121 is a direction perpendicular to the extending direction of the second rib portion 121 .
  • the width direction of the second rib portion 121 is the W direction.
  • the width direction of the second rib portion 121 is not limited to the W direction.
  • the second rib portions 121 extend in the L direction and are arranged in the W direction.
  • the plurality of second grooves 122 are arranged in the width direction of the second grooves 122, and the second ribs 121 are formed between the adjacent second grooves 122.
  • the second grooves 122 extend in the L direction and are arranged in the W direction, like the second ribs 121 .
  • the second rib portion 121 is formed between two adjacent second groove portions 122 .
  • the plurality of second grooves 122 and the plurality of second ribs 121 both extend in the L direction, and the second grooves 122 and the second ribs 121 are alternately arranged in the W direction.
  • the width of the second rib portion 121 is narrower than the width of the second groove portion 122 .
  • the width direction of the second rib portion 121 and the second groove portion 122 corresponds to the width direction (W direction) of the mold 10 . Therefore, in the cross section shown in FIG. 5A, the width of the second rib portion 121 means the width of the second rib portion 121 in the W direction, and the width of the second groove portion 122 means the width of the second groove portion 122 in the W direction.
  • the width of the second rib portion 121 and the width of the second groove portion 122 can be determined using, for example, vernier calipers.
  • the width of second rib portion 121 is narrower than the width of second groove portion 122 .
  • the width of the second rib portion 121 means the width of the second rib portion 121 in a cross section perpendicular to the extending direction of the second rib portion 121 . Therefore, the same effect as the relationship between the width of the first rib portion 111 and the width of the first groove portion 112 described above can be obtained. Specifically, when the second slow-cooling region 123 comes into contact with the material B during hot press-forming, the heat removal amount in the second groove portions 122 is less than the heat removal amount in the second rib portions 121 .
  • the width of the second rib portion 121 is narrower than the width of the second groove portion 122, the amount of heat removal in the second rib portion 121 can be reduced. Therefore, in the second slow cooling region 123, the cooling rate of the material B can be made slower than in the second rapid cooling region 124, which will be described later. Therefore, when hot press forming is performed using the mold 10, the degree of quenching of the area of the material B that is in contact with the second slow cooling area 123 can be reduced. As a result, the material B (hot press-formed product) after hot press-forming can be formed with a shock absorbing region with reduced strength.
  • second rib portion 121 and second groove portion 122 are not formed in second rapid cooling region 124 of second molding surface 120 of lower die 12 . That is, the second quench region 124 of the second molding surface 120 is a smooth surface. Therefore, substantially the entire second quench region 124 is in contact with the material B during hot press forming. Therefore, in the second rapid cooling region 124 , the cooling rate of the material B can be made faster than in the second slow cooling region 123 . Therefore, when hot press forming is performed using the mold 10, the degree of quenching of the area of the material B that is in contact with the second rapid cooling area 124 can be increased. As a result, it is possible to form a high-strength region having a higher strength than the impact buffer region in the material B (hot press-formed product) after hot press-forming.
  • first rib portion 111 and second rib portion 121 [Relationship between first rib portion 111 and second rib portion 121] Further, in the mold 10, during hot press molding, the first slow cooling region 113 of the first molding surface 110 and the second slow cooling region 123 of the second molding surface 120 are arranged in the normal direction of the first slow cooling region 113. When viewed from above, the first rib portion 111 and the second rib portion 121 at least partially overlap.
  • “at the time of hot press molding” means that substantially the entire molding surface 110 of the upper mold 11 and substantially the entire molding surface 120 of the lower mold 12 come into contact with the material B and apply an external force to the material B. It means a state in which the mold 10 is closed and the material B is cooled by the mold 10 while the upper mold 11 is held at the bottom dead center.
  • the first rib portion 111 does not enter the second groove portion 122 and the second rib portion 121 does not enter the first groove portion 112 during hot press molding. Therefore, during hot press forming, the first rib portion 111 enters the second groove portion 122 or the second rib portion 121 enters the first groove portion 112, thereby preventing the material B from being deformed into a wavy shape. can be suppressed.
  • the width of the first rib portion 111 of the first slow cooling region 113 is narrower than the width of the first groove portion 112 . Furthermore, the width of the second rib portion 121 in the second slow cooling region 123 is narrower than the width of the second groove portion 122 . Therefore, when hot press molding is performed using the mold 10 , the cooling rate is suppressed in the area of the material B sandwiched between the first slow cooling area 113 and the second slow cooling area 123 . Therefore, in the hot press-formed product, it is possible to form a shock buffering region with reduced strength and a high-strength region with a higher strength than the shock buffering region.
  • the first rib portion 111 and the second rib portion 121 overlap at least partially. Therefore, it is possible to suppress the material B from deforming into a wavy shape in the impact buffering region.
  • the first rib portion 111 and the second rib portion 121 preferably extend in the same direction. Moreover, the first groove 112 and the second groove 122 extend in the same way. 5A and 6, the first rib portion 111 and the second rib portion 121 extend in the L direction, and the first groove portion 112 and the second groove portion 122 extend in the L direction.
  • the heat transfer simulation of the material B is , it suffices to carry out a simulation in two dimensions. That is, if a two-dimensional simulation is performed on a cross section perpendicular to the extending direction of the first rib portion 111, the first groove portion 112, the second rib portion 121, and the second groove portion 122 (that is, the cross section shown in FIG. 5A), , the results are substantially the same as those obtained by three-dimensional simulations. Therefore, there is no need to perform a three-dimensional simulation. Therefore, the heat transfer of the material B can be easily and accurately simulated. That is, the cooling rate can be controlled more easily and accurately. In this case, it is possible to control the chemical composition of material B to a desired microstructure by using a simulation.
  • the hot press-formed product when material B is steel, as a result of hot press molding of material B, if the hot press-formed product has a microstructure containing not only a hard phase but also retained austenite, the impact of the hot press-formed product Further increases the absorption capacity.
  • the hard phase consists of martensite and/or bainite.
  • the width of the first rib portion 111 formed in the slow cooling region 113 is 10 to 50% of the width of the first groove portion 112
  • the width of the second rib portion 121 formed in the slow cooling region 123 is , 10 to 50% of the width of the second groove portion 122 .
  • the width of the first rib portion 111 is 10% or more of the width of the first groove portion 112
  • the first rib portion 111 removes heat from the material B appropriately. In this case, it is possible to prevent the cooling rate of the material B from becoming excessively slow. Therefore, the formation of ferrite and pearlite in the microstructure of material B can be suppressed, and the formation of hard phase or hard phase and retained austenite is promoted. As a result, the impact absorption capacity of the hot press-formed product is improved.
  • the cooling rate can be slowed down during hot press molding. If the cooling rate can be slowed down, it becomes easier to stop cooling at a desired material temperature. For example, cooling may be stopped between the Mf point and the Ms point to adjust the amount of martensite and retained austenite produced. For example, the cooling may be stopped at a temperature higher than the Ms point, and the microstructure of the material may be made mainly of bainite.
  • the width of the first rib portion 111 is 10-50% of the width of the first groove portion 112 . More preferably, the upper limit of the ratio of the width of the first rib portion 111 to the width of the first groove portion 112 is 45%, more preferably 40%, and even more preferably 35%. A more preferable lower limit of the ratio of the width of the first rib portion 111 to the width of the first groove portion 112 is 12%, more preferably 14%.
  • FIG. 5B is a schematic diagram of FIG. 5A excluding material B, showing the time of hot press molding.
  • the width of the first rib portion 111 is defined as follows. Of the surfaces of the first rib portion 111 , the surface facing the second molding surface 120 is defined as the top surface of the first rib portion 111 . That is, of the surfaces of the first rib portion 111, the surface that comes into contact with the material B during hot press molding is defined as the "top surface”. As shown in FIG. 5B , the width W 111P of the top surface 111P in the cross section perpendicular to the extending direction of the first rib portion 111 is defined as the width of the first rib portion 111 .
  • the width W 111P of the top surface 111P corresponds to the length of the top surface 111P in the direction (W direction in FIG. 5B) perpendicular to the extending direction of the first rib portion 111 and the normal direction of the top surface 111P.
  • the height of the first rib portion 111 is defined as follows. 5B, the height H 111P from the top surface 111P of the first rib portion 111 to the groove bottom 112P of the first groove portion 112 is defined as the height of the first rib portion 111. As shown in FIG. In other words, the length from the top surface 111P of the first rib portion 111 to the groove bottom 112P of the first groove portion 112 in the normal direction (V direction in FIG. Define height H 111P .
  • the width of the first groove portion 112 is defined as follows. As shown in FIG. 5B, in a cross section perpendicular to the extending direction of the first rib portion 111, the distance between the endpoint of one top surface 111P of the adjacent first rib portions 111 and the endpoint of the other top surface 111P of the adjacent first rib portions 111 The width W 112P of the gap is defined as the width of the first groove portion 112 .
  • the width of the second rib portion 121 is defined as follows. Of the surfaces of the second rib portion 121 , the surface facing the first molding surface 110 is defined as the top surface of the second rib portion 121 . That is, of the surfaces of the second rib portion 121, the surface that comes into contact with the material B during hot press molding is defined as the "top surface”. As shown in FIG. 5B, the width W121P of the top surface 121P in the cross section perpendicular to the extending direction of the second rib portion 121 is defined as the width of the second rib portion 121. As shown in FIG.
  • the width W121P of the top surface 121P corresponds to the length of the top surface 121P in the direction perpendicular to the extending direction of the second rib portion 121 and the normal direction of the top surface 121P (W direction in FIG. 5B).
  • the height of the second rib portion 121 is defined as follows. 5B, the height H121P from the top surface 121P of the second rib portion 121 to the groove bottom 122P of the second groove portion 122 is defined as the height of the second rib portion 121. As shown in FIG. In other words, the length from the top surface 121P of the second rib portion 121 to the groove bottom 122P of the second groove portion 122 in the normal direction of the top surface 121P (in FIG. Define height.
  • the width of the second groove portion 122 is defined as follows. As shown in FIG. 5B, in a cross section perpendicular to the extending direction of the second rib portion 121, the distance between the end point of one top surface 121P of the adjacent second rib portions 121 and the end point of the other top surface 121P The width W 122P of the gap is defined as the width of the second groove portion 122 .
  • the shape of the first rib portion 111 or the second rib portion 121 in a cross section perpendicular to the extending direction may be rectangular as shown in FIGS. 5A and 5B, or may be rectangular as shown in FIG. Alternatively, it may be trapezoidal in shape, the width of which narrows toward the top surface 111P or 121P.
  • the corners of the top surface 111P or 121P are chamfered, or the base of the first rib portion 111 or the second rib portion 121 is chamfered. It may have been.
  • the corners of the top surface 111P or 121P may be rounded (that is, filleted), or the base of the first rib portion 111 or the second rib portion 121 may be rounded (that is, filledeted). can be used).
  • the width of the top surface (111P or 121P) is the width of the portion of the top surface (111P and 121P) that is not chamfered or filleted.
  • the mold 10 of this embodiment is a mold for hot press molding.
  • the temperature of material B is A c 3 point or higher, which is higher than warm press molding. Therefore, the material B for hot press molding has a lower hardness and excellent workability than the material for warm press molding. Therefore, the surface pressure applied to the material B during hot press-forming is lower than that during warm press-forming. Therefore, even if the width of the first rib portion 111 is 50% or less of the width of the first groove portion 112, the surface of the material B is less likely to be scratched.
  • the width of the second rib portion 121 is 10% or more of the width of the second groove portion 122, excessive reduction in the cooling rate of the material B is suppressed. can. Therefore, the impact absorption capacity of the hot press-formed product is improved.
  • the cooling rate of the material B can be moderately slowed down. Therefore, it becomes easier to adjust the cooling stop temperature (that is, the temperature of the material B when the mold 10 is separated from the material B) during hot press molding.
  • the cooling stop temperature is adjusted to a temperature above the Ms point, the cooling stop temperature is adjusted between the Mf point and the Ms point, or the Ms point is adjusted to 500 ° C. easier.
  • the width of the second rib portion 121 is 10 to 50% of the width of the second groove portion 122 .
  • a preferable upper limit of the ratio of the width of the second rib portion 121 to the width of the second groove portion 122 is 45%, more preferably 40%, and still more preferably 35%.
  • a more preferable lower limit of the ratio of the width of the second rib portion 121 to the width of the second groove portion 122 is 12%, more preferably 14%.
  • the surface of the material B is scratch resistant.
  • the width of the first rib portion 111 is 1.0 to 8.0 mm, and the height of the first rib portion 111 is 0.2 to 5.0 mm.
  • the width of the second rib portion 121 is 1.0 to 8.0 mm, and the height of the second rib portion 121 is 0.2 to 5.0 mm.
  • the height of the first rib portion 111 corresponds to the depth of the first groove portion 112 .
  • the height of the second rib portion 121 corresponds to the depth of the second groove portion 122 .
  • the width of the first rib portion 111 or the width of the second rib portion 121 is 8.0 mm or less, the temperature variation in the width direction of the first rib portion 111 or the width direction of the second rib portion 121 in the material B is reduced. be able to. Therefore, it is possible to reduce variations in the cooling rate caused by variations in the temperature of the material B during hot press molding.
  • the width of the first rib portion 111 or the width of the second rib portion 121 is set to 1.0 mm or more, the first rib portion 111 or the second rib portion 121 is less likely to break during hot press molding. and increase productivity. Therefore, the preferred width of the first rib portion 111 is 1.0 to 8.0 mm. A preferable width of the second rib portion 121 is 1.0 to 8.0 mm.
  • a more preferable lower limit of the width of the first rib portion 111 is 1.8 mm, more preferably 2.0 mm.
  • a more preferable lower limit of the width of the second rib portion 121 is 1.8 mm, more preferably 2.0 mm. In this case, the first rib portion 111 and the second rib portion 121 are even less likely to break. In addition, since the dimensional accuracy of the first rib portion 111 and the second rib portion 121 is relaxed, processing becomes easier.
  • the height of the first rib portion 111 or the height of the second rib portion 121 is set to 0.2 mm or more, the occurrence of heat removal from the material B in the first groove portion 112 or the second groove portion 122 can be suppressed.
  • the height of the first rib portion 111 or the height of the second rib portion 121 is set to 5.0 mm or less, the first rib portion 111 or the second rib portion 121 is Less likely to break, higher productivity. Therefore, the preferred height of the first rib portion 111 is 0.2 to 5.0 mm.
  • a preferred height of the second rib portion 122 is 0.2 to 5.0 mm.
  • the width or height of the first rib portion 111 or the second rib portion 121 is adjusted as described above in at least a part of the first slow cooling region 113 and the second slow cooling region 123, , the above-mentioned preferable effect can be obtained in the above-mentioned at least part of the region. Therefore, in the present embodiment, if the width or height of the first rib portion 111 or the second rib portion 121 is adjusted as described above in at least a part of the first slow cooling region 113 and the second slow cooling region 123, good.
  • the width of the first rib portion 111 is 1.0 to 8.0 mm and the height is 0.2 to 5.0 mm over the entire first slow cooling region 113, and the second slow cooling region 123 , the width of the second rib portion 121 is 1.0 to 8.0 mm and the height is 0.2 to 5.0 mm.
  • the width of the first rib portion 111 is 1.0 to 4.0 mm and 10 to 30% of the width of the first groove portion 112.
  • the width of the second rib portion 121 is 1.0 to 4.0 mm and 10 to 30% of the width of the second groove portion 122. be.
  • the cooling rate of material B can be further reduced. Therefore, it is easy to adjust the cooling stop temperature to a desired temperature. Furthermore, the temperature variation of the material B during hot press molding can be reduced.
  • the first rib portion 111 and the second rib portion 121 extend in the same direction
  • the first groove portion 112 and the second groove portion 122 extend in the same direction
  • the width of the first rib portion 111 is 10 to 50% of the width of the first groove portion 112
  • the width of the second rib portion 121 is 10 to 50% of the width of the second groove portion 122
  • the first rib portion 111 and the second rib portion 121 is 1.0 to 8.0 mm
  • the height of the first rib portion 111 and the second rib portion 121 is 0.2 to 5.0 mm.
  • Fn1 defined by formula (1) is preferably 14 or less.
  • Fn1 Wr0.9 / P00.8 +0.05Hr (1)
  • Wr is the width (mm) of the first rib portion 111 and the second rib portion 121 .
  • P0 Wr/Ws, where Ws is the width (mm) of the first groove 112 and the second groove 122 .
  • Hr is the height (mm) of the first rib portion 111 and the second rib portion 121 .
  • FIG. 8 is a diagram showing the relationship between Fn1 and the temperature variation ⁇ T (°C) in the first slow cooling region 113 and the second slow cooling region 123.
  • FIG. FIG. 8 shows results obtained by the following two-dimensional heat transfer simulation. Specifically, the temperature distribution of the material B during hot press molding and the change over time of the temperature distribution were simulated by the finite difference method assuming the heat conduction model shown in FIG.
  • FIG. 9 is a widthwise cross-sectional view of the first rib portion 111 and the second rib portion 121 in the first slow cooling region 113 and the second slow cooling region 123 .
  • the material B was divided into a plurality of elements E each having an element width D0 of 1 mm, a thickness D1 of the material B (assumed to be 1.4 mm), and a unit length in the L direction.
  • the balance Q (W/m 2 ) of the amount of heat per unit time (1 second) due to heat conduction and heat transfer in the i-th (i is a natural number) element E is shown by the following formula.
  • the first rib portion 111 and the second rib portion 121 extend in the same direction, and the first groove portion 112 and the second groove portion 122 extend in the same direction.
  • the width of the first rib portion 111 is the same as the width of the second rib portion 121 and the height of the first rib portion 111 is the same as the height of the second rib portion 121 .
  • the width of the first groove portion 112 is the same as the width of the second groove portion 122 .
  • the entire top surface of the first rib portion 111 overlaps the entire top surface of the second rib portion 121 during hot press molding.
  • the cross-sectional shape perpendicular to the extending direction of the rib portions (111 and 121) was rectangular.
  • the temperature Tbi of element E at time 0 (second) was set to 622°C. Furthermore, it is assumed that the element E is in contact with the first rib portion 111 and the second rib portion 121 in sections of 500 to 1000 mm on the right and left sides of FIG. ), and as a boundary condition, the heat conduction in the material B in the element E at the points of 1000 mm on the right and left sides of FIG. 9 is assumed to be adiabatic. Then, the temperature distribution of the material B and its change over time were simulated by performing sequential calculations for calculating the temperature change ⁇ Tb of the element E at intervals of 0.01 second.
  • the difference Tbimax ⁇ Tbimin was defined as the temperature variation ⁇ T (° C.) of the material B and obtained.
  • FIG. 8 was created using the obtained ⁇ T.
  • the preferred upper limit of Fn1 is 14, more preferably 10. If Fn1 is 14 or less, for example, the temperature variation ⁇ T of material B is 110° C. or less. Also, if Fn1 is 10 or less, for example, the temperature variation ⁇ T of the material B is 40° C. or less.
  • the first rib portion 111 and the second rib portion 121 extend in the same direction, the first groove portion 112 and the second groove portion 122 extend in the same direction, and the width of the first rib portion 111 is 10 to 50% of the width of the first groove portion 112, the width of the second rib portion 121 is 10 to 50% of the width of the second groove portion 122, and the width of the first rib portion 111 and the second rib portion 121 is Assume that the width is 1.0 to 8.0 mm and the height of the first rib portion 111 and the second rib portion 121 is 0.2 to 5.0 mm.
  • Fn2 defined by formula (2) is preferably 30 or more.
  • Ws is the width (mm) of the first groove portion 112 and the second groove portion 122 .
  • Wr is the width (mm) of the first rib portion 111 and the second rib portion 121 .
  • Hr is the height (mm) of the first rib portion 111 and the second rib portion 121 .
  • FIG. 10 is a diagram showing the relationship between Fn2 and the cooling rate V (°C/sec) of material B during hot press molding.
  • FIG. 10 was obtained by the above two-dimensional heat transfer simulation using the heat transfer model shown in FIG.
  • the cooling rate V was obtained by averaging temperature changes of the element E per unit time from time 0 to the time when the temperature of the element E reached 400°C.
  • the element E used for calculating the cooling rate is an element whose temperature Tbi indicates Tbimax.
  • the cooling rate V of material B rapidly decreases, and thereafter the rate of decrease in cooling rate V becomes moderate. Therefore, the preferred lower limit for Fn2 is 30, more preferably 45, and even more preferably 90. If Fn2 is 30 or more, for example, the cooling rate V of material B is 80° C./second or less. Therefore, during hot press molding, it becomes easier to adjust the cooling stop temperature (that is, the temperature of the material B when the mold 10 is separated from the material B) to a desired temperature. If Fn2 is 45 or more, for example, the cooling rate of material B is 70° C./second or less. Therefore, it becomes easier to adjust the cooling stop temperature to a desired temperature. If Fn2 is 90 or more, for example, the cooling rate V of material B is 50° C./second or less. Therefore, it becomes easier to adjust the cooling stop temperature to a desired temperature.
  • Fn1 is more preferably 14 or less and Fn2 is 30 or more.
  • the temperature variation ⁇ T of the material B can be further suppressed, and the cooling stop temperature can be easily adjusted to a desired temperature.
  • the first rib portion 111 and the second rib portion 121 extend in the same direction, the first groove portion 112 and the second groove portion 122 extend in the same direction, and the first rib
  • the width of the portion 111 is 1.0 to 4.0 mm and 10 to 30% of the width of the first groove portion 112, and the width of the second rib portion 121 is 1.0 to 4.0 mm. and 10 to 30% of the width of the second groove portion 122, Fn1 is 14 or less, and/or Fn2 is 30 or more.
  • the cooling rate of material B can be further reduced. Therefore, it is easy to adjust the cooling stop temperature to a desired temperature. Furthermore, the temperature variation of the material B during hot press molding can be reduced.
  • the mold 10 according to this embodiment is not limited to the configuration described above.
  • mold 10 is not limited to the shape shown in FIG.
  • the first molding surface 110 and the second molding surface 120 of the mold 10 may be curved in the longitudinal direction.
  • the cross-sectional shape perpendicular to the longitudinal direction (L direction) of the first molding surface 110 of the upper mold 11 of the mold 10 is not limited to a concave shape.
  • the cross-sectional shape perpendicular to the longitudinal direction (L direction) of the second molding surface 120 of the lower mold 12 is not limited to a convex shape.
  • the shapes of the first molding surface 110 and the second molding surface 120 are not particularly limited.
  • the arrangement of the first slow cooling region 113 on the first molding surface 110 is not particularly limited.
  • the arrangement of the second slow cooling region 123 on the second molding surface 120 is not particularly limited. It is sufficient that the first molding surface 110 includes the first slow cooling region 113 and the second molding surface 120 includes the second slow cooling region 123 .
  • the first slow cooling region 113 and the second slow cooling region 123 are not limited to the form shown in FIG.
  • FIG. 11 is a perspective view showing another example different from FIG. 2 of the mold 10 according to this embodiment.
  • the first slow cooling region 113 may be arranged on the entire bottom surface of the groove of the concave portion of the first molding surface 110 of the upper mold 11 of the mold 10 .
  • a second slow cooling region 123 may be arranged on the entire upper surface of the convex portion of the second molding surface 120 of the lower mold 12 of the mold 10 .
  • FIG. 12 is a perspective view showing another example of the mold 10 according to this embodiment, which is different from FIGS. 2 and 11.
  • a first slow cooling region 113 may be arranged on a part of the side surface of the concave portion of the first molding surface 110 of the upper mold 11 of the mold 10 .
  • a second slow cooling region 123 may be arranged on a part of the side surface of the convex portion of the second molding surface 120 of the lower mold 12 of the mold 10 .
  • FIG. 13 is a perspective view showing another example different from FIGS. 2, 11 and 12 of the mold 10 according to this embodiment. 2, 11 and 12, the first molding surface 110 includes a first slow cooling zone 113 and a first quenching zone 114.
  • the second forming surface 120 includes a second slow cooling region 123 and a second rapid cooling region 124 .
  • the entire first molding surface 110 may be the first slow cooling region 113 .
  • the second molding surface 120 as a whole may be the second slow cooling region 123 .
  • the first molding surface 110 includes the first slow cooling region 113 and the second molding surface 120 includes the second slow cooling region 123
  • the first slow cooling region 113 in the first molding surface 110 and the position of the second slow cooling region 123 in the second molding surface 120 are not particularly limited.
  • the upper mold 11 and the lower mold 12 are in contact with the material B and are pressing the material B during hot press molding, at least part of the first slow cooling area 113 is replaced by the second slow cooling area 123 and at least a portion of the are arranged opposite each other.
  • the first slow cooling region 113 can also be defined as a part of the region in which the first rib portion 111 and the first groove portion 112 are formed.
  • the second slow cooling region 123 can also be defined as a partial region of the region where the second rib portion 121 and the second groove portion 122 are formed.
  • the width of the first rib portion 111 is narrower than the width of the first groove portion 112 in at least a partial region of the first molding surface 110, and the width of the second molding surface 120 is at least partially wide.
  • the width of the second rib portion 121 is narrower than the width of the second groove portion 122 .
  • the extending direction of the first rib portion 111 and the extending direction of the second rib portion 121 are not particularly limited.
  • the first rib portion 111 and the second rib portion 121 do not have to extend in the L direction shown in FIGS. 5A and 6 .
  • FIG. 14 is another example different from FIG. 5A among schematic diagrams in which the region 100 in FIG. 3 is enlarged.
  • 15 is a cross-sectional view taken along the line segment XV--XV of FIG. 14.
  • the first rib portion 111, the first groove portion 112, the second rib portion 121, and the second groove portion 122 all extend in the W direction, and the L lined up in the direction
  • the width of the first rib portion 111, the width of the first groove portion 112, the width of the second rib portion 121, and the width of the second groove portion 122 all mean the width of the mold 10 in the L direction.
  • the upper mold 11 moves in the V direction together with the slide 3.
  • the material B is hot press-molded by the first molding surface 110 of the upper mold 11 and the second molding surface 120 of the lower mold 12 .
  • the metal flow of the material B proceeds in the W direction by hot press molding. That is, in the region 100, the material B slides in the W direction with respect to the first molding surface 110 and the second molding surface 120. As shown in FIG.
  • the material B is the first rib.
  • the material B is less likely to receive frictional resistance from the portion 111 and/or the second rib portion 121 and easily slides on the first rib portion 111 and/or the second rib portion 121 . Therefore, formation of flaws on the surface of the material B can be suppressed.
  • first rib portion 111, the first groove portion 112, the second rib portion 121, and the second groove portion 122 extend in the sliding direction of the material B during the hot press forming process. In this case, it is possible to suppress the formation of flaws on the surface of the material B during the hot press forming process.
  • FIG. 16 is another example different from FIGS. 5A and 14 in a schematic diagram in which the region 100 in FIG. 3 is enlarged.
  • FIG. 17 is a schematic diagram showing only the rib portion when the region 100 of FIG. 16 is viewed from the normal direction of the first slow cooling region 113 .
  • FIGS. 5A and 6 are schematic diagrams showing only the rib portion when the region 100 of FIG. 16 is viewed from the normal direction of the first slow cooling region 113 .
  • first rib portion 111 and the second rib portion 121 may at least partially overlap each other.
  • FIG. 18 is another example different from FIGS. 5A, 14, and 16 in the enlarged schematic diagram of the region 100 in FIG.
  • FIG. 19 is a schematic diagram showing only the rib portion when viewing the region 100 of FIG. 18 from the normal direction of the first slow cooling region.
  • the plurality of first grooves 112 and the plurality of first ribs 111 both extend in the L direction, and the plurality of second grooves 122 and the plurality of second ribs 121 may extend in the W direction.
  • first rib portion 111 and second rib portion 121 at least partially overlap when mold 10 is closed.
  • the first slow cooling region 113 and the second slow cooling region 123 of the present embodiment preferably do not have supply ports for supplying the cooling medium to the surfaces of the first slow cooling region 113 and the second slow cooling region 123. preferable. If the first slow cooling region 113 and the second slow cooling region 123 have supply ports, the air remaining in the pipes inside the mold 10 (upper mold 11, lower mold 12) leading to the supply ports Excessive heat removal from the material B is facilitated in the portions of the first slow-cooling region 113 and the second slow-cooling region 123 that have the supply port. Therefore, the temperature variation of the material B may be promoted.
  • the upper mold 11 and the lower mold 12 may have cooling passages through which a cooling medium passes. In this case, the temperatures of the upper mold 11 and the lower mold 12 during hot press molding can be kept sufficiently low.
  • a method for manufacturing a hot press-formed product by hot press-forming using the mold 10 will be described.
  • a method for manufacturing a hot press-formed product according to the present embodiment includes the following steps. ⁇ Preparation process ⁇ Heating process ⁇ Hot press molding process ⁇ Mold releasing process Each process will be described below.
  • a material B having a desired chemical composition is prepared.
  • the material B is not particularly limited.
  • Material B is, for example, a steel plate.
  • the type of steel plate is not particularly limited.
  • the material B may be, for example, a steel plate subjected to surface treatment such as plating, or may be a steel plate not subjected to surface treatment such as plating (so-called bare material).
  • the plating treatment may be a hot dip galvanizing treatment, an alloyed hot dip galvanizing treatment, or an aluminum plating treatment.
  • the chemical composition of the base material steel plate of material B is not particularly limited as described above.
  • the base material steel plate of material B for example, in mass%, C: 0.10 to 0.60%, Si: 0 to 5.0%, Mn: 0 to 5.0%, P: 0.100% or less, S: 0.100% or less, N: 0.100% or less, O: 0.100% or less, Al: 0 to 1.0%, Cr: 0 to 3.0%, Mo: 0 to 5.0% , V: 0-2.0%, Nb: 0-1.0%, Ti: 0-1.0%, B: 0-1.0%, Ca: 0-1.0%, Mg: 0- 1.0%, Zr: 0-1.0%, Rare earth elements: 0-1.0%, Co: 0-5.0%, W: 0-5.0%, Ni: 0-3.0% , Cu: 0-3.0%, and the balance being Fe and impurities.
  • the impurities are elements that are mixed from ore, scrap, or the manufacturing environment as raw materials when industrially manufacturing steel materials, and have an
  • the thickness of material B is not particularly limited, but is selected according to the characteristics of the hot press-formed product to be obtained.
  • the thickness of the material B is, for example, 0.6-3.2 mm.
  • the mechanical properties of material B are also not particularly limited. The mechanical properties of the material B are appropriately selected according to the properties of the hot press-formed product to be obtained.
  • the tensile strength of material B may be, for example, 400 MPa or more.
  • the method of preparing material B is not particularly limited.
  • the raw material B may be manufactured from molten steel having the chemical composition described above by a known manufacturing method. It may be prepared by purchasing material B manufactured by a third party.
  • the prepared material B is heated to a temperature of Ac3 or higher. If the heating temperature is less than the Ac3 point, the material B will not become an austenite single phase. In this case, when the material B is cooled in the hot press forming process, the hard phase (martensite and/or bainite) is formed in the area sandwiched between the first quenched region 114 and the second quenched region 124 in the material B. Insufficient formation. Therefore, sufficient strength may not be obtained. If the heating temperature is A c3 point or more, the material B before the hot press forming process becomes austenite single phase.
  • the heating temperature is preferably less than 950°C. In this case, the heating time of the material B can be shortened, and the productivity can be improved. Furthermore, since the fuel and power required for heating can be reduced, manufacturing costs can be suppressed.
  • the method of heating material B is not particularly limited.
  • the material B may be heated using a heating furnace such as an electric furnace, gas furnace, far-infrared furnace, or near-infrared furnace.
  • the material B may be heated using an electric heating device, a high-frequency induction heating device, or the like.
  • the method for heating the material B is not limited, and a known heating method can be appropriately selected.
  • Hot press molding process In the hot press-molding step, the material B heated to the Ac 3 point or higher is hot press-molded using the above-described mold 10 .
  • the material B heated in the heating process is placed on the second molding surface 120 of the lower mold 12 .
  • the upper mold 11 is brought relatively closer to the lower mold 12, and the mold 10 is closed.
  • the material B contacts the first molding surface 110 of the upper mold 11 and the second molding surface 120 of the lower mold 12 .
  • the material B is sandwiched between the first molding surface 110 of the upper mold 11 and the second molding surface 120 of the lower mold 12 .
  • Hot press molding is performed on the material B by the upper mold 11 and the lower mold 12 .
  • the material B is not cooled using a cooling medium during hot press-forming. Instead, heat is removed from the material B by the mold 10 that contacts the material B during hot press molding.
  • the mold 10 When the mold 10 is closed, the first rib portion 111 of the first molding surface 110 of the upper mold 11 and the material B are in contact with each other in the first slow cooling region 113 .
  • the second rib portion 121 of the second molding surface 120 of the lower mold 12 and the material B are in contact with each other in the second slow cooling region 123 .
  • the temperature of the upper mold 11 and the lower mold 12 is sufficiently lower than that of the material B. Therefore, the heat of the material B is removed by the first rib portion 111 and the second rib portion 121 .
  • the temperature of the upper mold 11 and the lower mold 12 is, for example, room temperature (20 ⁇ 15°C) to 200°C.
  • the hot press-formed material B is released from the mold 10 to produce a hot press-formed product.
  • the temperature of the material B (hot press-formed product) when released from the mold 10 is defined as the cooling stop temperature.
  • the cooling stop temperature is between the Mf point and Ms point of the hot press-formed product, or between the Ms point and above and 500 ° C.
  • the microstructure of the hot press-formed product is a structure consisting of a hard phase, Alternatively, a structure consisting of a hard phase and retained austenite is obtained. In this case, the resulting hot press-formed product has excellent impact absorption ability.
  • the temperature of the region sandwiched between the first slow cooling region 113 and the second slow cooling region 123 of the material B is Mf
  • the material B is released from the mold 10 when the temperature is between the point and the Ms point, or when the temperature is above the Ms point and between 500°C.
  • the Ms point and Mf point of material B differ depending on the chemical composition of material B. Therefore, when attempting to obtain a structure consisting of a hard phase or a structure consisting of a hard phase and retained austenite in the material B, the preferred cooling stop temperature differs depending on the chemical composition of the material B.
  • the first rib portion 111, the first groove portion 112, the second Based on the width and height of the two rib portions 121 and the second groove portions 122 and the chemical composition of the material B, a heat transfer simulation was performed to determine the first slow cooling region 113 and the second slow cooling region of the material B.
  • a hot press-formed product having a structure consisting of a hard phase or a structure consisting of a hard phase and retained austenite can be hot-pressed according to the chemical composition of the material B. It can be manufactured by molding.
  • the method for manufacturing a hot press-formed product according to the present embodiment may further include manufacturing steps other than those described above.
  • a heating and holding step in a temperature range of 500° C. or less may be performed after the mold release step.
  • the hot press-formed product after the mold release process is heated and held in a temperature range of 500°C or less.
  • the hot press-formed product produced by releasing from the mold 10 is held at a heating temperature of 100 to 500.degree.
  • the heat hold can distribute carbon from the hard phases to the retained austenite in the microstructure of the hot pressed part.
  • the formation of retained austenite is accelerated due to the enrichment of carbon in the retained austenite.
  • the proportion of retained austenite increases in the hot press-formed product.
  • the retained austenite transforms into martensite during impact deformation, improving the ductility of the hot press-formed product (so-called TRIP (transformation induced plasticity) effect).
  • TRIP transformation induced plasticity
  • the preferred upper limit of the heating and holding temperature is 400°C.
  • the heating and holding temperature is preferably -209° C. or higher at the Ms point. In this case, the impact absorption capacity of the hot press-formed product is stabilized and further enhanced. Therefore, when the Ms point -209°C exceeds 100°C, the preferable lower limit of the heating and holding temperature is the Ms point -209°C.
  • the heating holding time is not particularly limited.
  • the holding time at the heating and holding temperature is preferably 5 seconds to 30 minutes (1800 seconds), for example.

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Abstract

Provided is a mold capable of manufacturing, by hot-press molding, a hot-press molded article having excellent shock absorption ability. A mold (10) according to the present disclosure is provided with an upper mold (11) having a first molding surface (110), and a lower mold (1) having a second molding surface (120). The first molding surface (110) includes a first gradual cooling region (113) having a plurality of first ribs (111) and a plurality of first grooves (112). The width of the first ribs (111) is less than the width of the first grooves (112). The second molding surface (120) includes a second slow cooling region (123) having a plurality of second ribs (121) and a plurality of second grooves (122). The width of each of the second ribs (121) is less than the width of each of the second grooves (122). When viewed from the normal direction of the first slow cooling region (113) and the second slow cooling region (123), the first ribs (111) and the second ribs (121) at least partially overlap during hot-press molding.

Description

金型及び熱間プレス成形品の製造方法Method for manufacturing molds and hot press-formed products
　本開示は金型、及び、その金型を用いた熱間プレス成形品の製造方法に関する。 The present disclosure relates to a mold and a method for manufacturing a hot press-formed product using the mold.
　自動車分野では、燃費の向上のため、車体の軽量化が求められる。自動車分野ではさらに、衝突時の乗員保護のため、衝突安全性の向上も求められる。車体の軽量化には、車体に用いられる構造部材の薄肉化が有効である。構造部材を薄肉化しつつ衝突安全性の向上を図るため、車体の構造部材に適用される素材には、高い強度が求められる。一方、高い強度を有する素材は、プレス成形性が低い。高い強度を有する素材を冷間でプレス成形すると、プレス成形時に割れが発生したり、プレス成形により発生した応力により、素材が弾性変形する現象（スプリングバック）が起こったりする。そこで、このような高い強度を有する素材を用いて構造部材を成形する方法として、熱間プレス成形が提案されている。 In the automotive field, there is a demand for lighter vehicle bodies in order to improve fuel efficiency. In the automotive field, there is also a demand for improved collision safety in order to protect passengers in the event of a collision. In order to reduce the weight of the vehicle body, it is effective to reduce the thickness of the structural members used in the vehicle body. In order to improve collision safety while reducing the thickness of structural members, high strength is required for the materials used in the structural members of vehicle bodies. On the other hand, materials with high strength have low press formability. When a high-strength material is cold press-formed, cracks may occur during press-molding, or a phenomenon (springback) in which the material undergoes elastic deformation due to the stress generated by press-molding may occur. Therefore, hot press forming has been proposed as a method for forming structural members using such materials having high strength.
　熱間プレス成形では、ミクロ組織がオーステナイト単相となる温度域まで素材を加熱する。そして、加熱された素材を、金型を備える熱間プレス装置を用いて熱間でプレス成形する。熱間プレス成形では、加熱により素材が軟質化される。そのため、熱間プレス成形での素材のプレス成形性は高い。熱間プレス成形ではさらに、熱間プレス成形中の素材が金型の成形面の略全体と接触する。このとき、素材は、素材と接触する金型によって抜熱され、焼入れされる。このように、熱間プレス成形では、素材は熱間プレス成形されると同時に焼入れされる。そのため、熱間プレス成形では、高強度の熱間プレス成形品を容易に製造することができる。 　In hot press forming, the material is heated to a temperature range where the microstructure becomes an austenite single phase. Then, the heated raw material is hot press-molded using a hot press device equipped with a mold. In hot press molding, the material is softened by heating. Therefore, the press formability of the material in hot press forming is high. In hot press forming, the material being hot pressed also contacts substantially the entire forming surface of the mold. At this time, the material is quenched by removing heat from the metal mold that is in contact with the material. Thus, in hot press forming, the material is hot press formed and quenched at the same time. Therefore, hot press-molding can easily produce a high-strength hot-press-molded product.
　ところで、自動車の構造部材の１種である衝撃吸収部材では、優れた衝撃吸収能が求められる。そこで、衝撃吸収部材を成形するための熱間プレス成形用の金型が、特許文献１（特開２０１４－７９７９０号公報）に提案されている。 By the way, a shock absorbing member, which is one type of automobile structural member, is required to have excellent shock absorbing ability. Therefore, a hot press-molding mold for molding an impact absorbing member has been proposed in Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2014-79790).
　特許文献１に開示される熱間プレス成形では、加熱された素材を、金型を用いて熱間プレス成形する。熱間プレス成形時においてさらに、金型と素材との隙間の一部に冷媒を流して、素材を部分的に急冷する。具体的には、特許文献１の金型は、金型内部の冷媒路中の冷媒を金型外部に供給する供給口を、金型表面に備える。特許文献１の金型はさらに、素材のうちの高強度部と低強度部との境界領域と接触する凸部を備える。熱間プレス成形時に、高強度部と金型との隙間には、供給口から冷媒が供給される。一方、低強度部と金型との隙間には、冷媒は供給されない。高強度部と低強度部との境界に接触する凸部が、冷媒を堰き止める。そのため、高強度部と金型との隙間に充填された冷媒は、低強度部と金型との隙間には流れない。その結果、衝撃吸収能に優れた低強度部を備える熱間プレス成形品（衝撃吸収部材）が製造される。 In the hot press molding disclosed in Patent Document 1, a heated material is hot press molded using a mold. At the time of hot press molding, the material is partially quenched by flowing a coolant through part of the gap between the mold and the material. Specifically, the mold of Patent Document 1 has a supply port on the surface of the mold for supplying the coolant in the coolant passage inside the mold to the outside of the mold. The mold of Patent Document 1 further includes a convex portion that contacts a boundary region between the high-strength portion and the low-strength portion of the material. During hot press molding, a coolant is supplied from the supply port to the gap between the high-strength portion and the mold. On the other hand, the coolant is not supplied to the gap between the low-strength portion and the mold. A convex portion that contacts the boundary between the high-strength portion and the low-strength portion dams up the refrigerant. Therefore, the coolant filled in the gap between the high-strength portion and the mold does not flow into the gap between the low-strength portion and the mold. As a result, a hot press-formed product (impact-absorbing member) having a low-strength portion with excellent impact-absorbing ability is produced.
特開２０１４－７９７９０号公報JP 2014-79790 A
　特許文献１に開示される金型では、衝撃吸収能に優れた低強度部を備える熱間プレス成形品を製造できる。しかしながら、特許文献１に記載の技術と異なる他の技術により、優れた衝撃吸収能を有する熱間プレス成形品が製造できてもよい。 With the mold disclosed in Patent Document 1, a hot press-formed product having a low-strength portion with excellent shock absorption ability can be manufactured. However, a hot press-formed product having excellent impact absorption ability may be produced by other techniques different from the technique described in Patent Document 1.
　本開示の目的は、熱間プレス成形によって、優れた衝撃吸収能を有する熱間プレス成形品を製造可能な金型、及び、その金型を用いた熱間プレス成形品の製造方法を提供することである。 An object of the present disclosure is to provide a mold capable of producing a hot press-formed product having excellent impact absorption ability by hot press molding, and a method for producing a hot press-formed product using the mold. That is.
　本開示による金型は、素材に対して熱間プレス成形を実施するための金型である。
　金型は、上型と、下型とを備える。上型は、第１成形面を有する。下型は、第２成形面を有する。第２成形面は、熱間プレス成形時において、第１成形面と対向して配置され、第１成形面とともに、素材を熱間プレス成形する。
　第１成形面は、第１緩冷却領域を含む。第１緩冷却領域は、複数の第１リブ部と複数の第１溝部とを有する。複数の第１リブ部は、第１リブ部の幅方向に配列される。複数の第１溝部は、第１溝部の幅方向に配列される。第１リブ部は、隣り合う第１溝部の間に形成されている。第１リブ部の幅は、第１溝部の幅よりも狭い。
　第２成形面は、第２緩冷却領域を含む。第２緩冷却領域は、複数の第２リブ部と複数の第２溝部とを有する。複数の第２リブ部は、第２リブ部の幅方向に配列される。複数の第２溝部は、第２溝部の幅方向に配列される。第２リブ部は、隣り合う第２溝部の間に形成されている。第２リブ部の幅は、第２溝部の幅よりも狭い。
　熱間プレス成形時において、第１緩冷却領域及び第２緩冷却領域を、第１緩冷却領域の法線方向から見たとき、第１リブ部と第２リブ部とは、少なくとも一部が重複している。 A mold according to the present disclosure is a mold for performing hot press molding on a material.
The mold includes an upper mold and a lower mold. The upper mold has a first molding surface. The lower mold has a second molding surface. The second molding surface is arranged to face the first molding surface during hot press molding, and together with the first molding surface hot press mold the material.
The first molding surface includes a first slow cooling region. The first slow cooling region has a plurality of first ribs and a plurality of first grooves. The plurality of first rib portions are arranged in the width direction of the first rib portion. The plurality of first grooves are arranged in the width direction of the first grooves. The first rib is formed between adjacent first grooves. The width of the first rib portion is narrower than the width of the first groove portion.
The second molding surface includes a second slow cooling region. The second slow cooling region has a plurality of second rib portions and a plurality of second groove portions. The plurality of second rib portions are arranged in the width direction of the second rib portions. The plurality of second grooves are arranged in the width direction of the second grooves. The second rib is formed between adjacent second grooves. The width of the second rib portion is narrower than the width of the second groove portion.
During hot press forming, when the first slow cooling region and the second slow cooling region are viewed from the normal direction of the first slow cooling region, at least a part of the first rib portion and the second rib portion Duplicate.
　本開示による熱間プレス成形品の製造方法は、素材を準備する工程と、準備された素材をＡｃ３点以上の温度に加熱する工程と、加熱された素材に対して、上述の金型により熱間プレス成形を実施する工程と、熱間プレス成形された素材を、金型から離型して、熱間プレス成形品を製造する工程とを備える。 The method for manufacturing a hot press-formed product according to the present disclosure includes the steps of preparing a material, heating the prepared material to a temperature of A c 3 or more, and applying the heated material with the above-described mold. It comprises a step of performing hot press molding, and a step of releasing the hot press-molded material from the mold to produce a hot press-molded product.
　本開示による金型は、熱間プレス成形によって、優れた衝撃吸収能を有する熱間プレス成形品を製造できる。本開示による熱間プレス成形品の製造方法は、優れた衝撃吸収能を有する熱間プレス成形品を製造できる。 A mold according to the present disclosure can produce a hot press-formed product having excellent impact absorption capability by hot press-forming. The method for producing a hot press-formed product according to the present disclosure can produce a hot press-formed product having excellent impact absorption capacity.
図１は、熱間プレス成形用の熱間プレス装置の一例を示す正面図である。FIG. 1 is a front view showing an example of a hot press device for hot press molding. 図２は、本実施形態による金型の一例を示す斜視図である。FIG. 2 is a perspective view showing an example of the mold according to this embodiment. 図３は、本実施形態による金型の一例の緩冷却領域における、熱間プレス成形時の金型及び素材の状態を示す断面図である。FIG. 3 is a cross-sectional view showing the state of the mold and material during hot press molding in the slow cooling region of an example of the mold according to the present embodiment. 図４は、本実施形態による金型の一例の急冷領域における、熱間プレス成形時の金型及び素材の状態を示す断面図である。FIG. 4 is a cross-sectional view showing the state of the mold and the material during hot press molding in the quench region of an example of the mold according to this embodiment. 図５Ａは、図３の領域１００を拡大した模式図である。FIG. 5A is an enlarged schematic diagram of region 100 in FIG. 図５Ｂは、熱間プレス成形時を示す図５Ａの素材Ｂを除いた模式図である。FIG. 5B is a schematic diagram of FIG. 5A excluding material B, showing the time of hot press molding. 図５Ｃは、図５Ａ及び図５Ｂと異なる形状の第１リブ部又は第２リブ部の延在方向に垂直な断面図である。FIG. 5C is a cross-sectional view perpendicular to the extending direction of the first rib portion or the second rib portion having a shape different from that of FIGS. 5A and 5B. 図５Ｄは、図５Ａ～図５Ｃと異なる形状の第１リブ部又は第２リブ部の延在方向に垂直な断面図である。FIG. 5D is a cross-sectional view perpendicular to the extending direction of the first rib portion or the second rib portion having a shape different from that of FIGS. 5A to 5C. 図６は、図３の領域１００を上方向（第１緩冷却領域及び第２緩冷却領域の法線方向）から見た、領域１００の模式図である。FIG. 6 is a schematic diagram of the region 100 of FIG. 3 as viewed from above (the normal direction of the first slow cooling region and the second slow cooling region). 図７は、図４の領域２００を拡大した模式図である。FIG. 7 is a schematic diagram enlarging the region 200 in FIG. 図８は、Ｆｎ１と、第１緩冷却領域及び第２緩冷却領域での温度ばらつきΔＴ（℃）との関係を示す図である。FIG. 8 is a diagram showing the relationship between Fn1 and the temperature variation ΔT (° C.) in the first slow cooling region and the second slow cooling region. 図９は、図８を作成するための２次元熱伝達シミュレーションで用いた熱伝導モデルの模式図である。FIG. 9 is a schematic diagram of the heat conduction model used in the two-dimensional heat transfer simulation for creating FIG. 図１０は、Ｆｎ２と、熱間プレス成形時の素材Ｂの冷却速度Ｖ（℃／秒）との関係を示す図である。FIG. 10 is a diagram showing the relationship between Fn2 and the cooling rate V (°C/sec) of material B during hot press molding. 図１１は、本実施形態による金型の図２とは異なる他の一例を示す斜視図である。FIG. 11 is a perspective view showing another example different from FIG. 2 of the mold according to this embodiment. 図１２は、本実施形態による金型の図２及び図１１とは異なる他の一例を示す斜視図である。FIG. 12 is a perspective view showing another example of the mold according to this embodiment, which is different from FIGS. 2 and 11. FIG. 図１３は、本実施形態による金型の図２、図１１及び図１２とは異なる他の一例を示す斜視図である。FIG. 13 is a perspective view showing another example different from FIGS. 2, 11 and 12 of the mold according to this embodiment. 図１４は、図３の領域１００を拡大した模式図のうち、図５Ａとは異なる他の一例である。FIG. 14 is another example different from FIG. 5A among schematic diagrams in which the region 100 in FIG. 3 is enlarged. 図１５は、図１４の線分ＸＶ－ＸＶでの断面図である。15 is a cross-sectional view taken along the line segment XV-XV in FIG. 14. FIG. 図１６は、図３の領域１００を拡大した模式図のうち、図５Ａ及び図１４とは異なる他の一例である。FIG. 16 is another example different from FIGS. 5A and 14 in a schematic diagram in which the region 100 in FIG. 3 is enlarged. 図１７は、図１６の領域１００を第１緩冷却領域の法線方向から見て、リブ部のみを図示した模式図である。FIG. 17 is a schematic diagram showing only the rib portion when viewing the region 100 of FIG. 16 from the normal direction of the first slow cooling region. 図１８は、図３の領域１００を拡大した模式図のうち、図５Ａ、図１４及び図１６とは異なる他の一例である。FIG. 18 is another example different from FIGS. 5A, 14, and 16 in the enlarged schematic diagram of the region 100 in FIG. 図１９は、図１８の領域１００を第１緩冷却領域の法線方向から見て、リブ部のみを図示した模式図である。FIG. 19 is a schematic diagram showing only the rib portion when viewing the region 100 of FIG. 18 from the normal direction of the first slow cooling region.
　上述のとおり、自動車の構造部材のうち衝撃吸収部材では、衝突時の衝撃エネルギーの吸収能、すなわち衝撃吸収能の向上が求められる。衝撃エネルギーは、構造部材が塑性変形することにより、吸収される。そのため、衝撃吸収能を高めるには、高い応力を受けた場合にも優れた塑性変形能を発揮できることが有効である。 As mentioned above, among the structural members of automobiles, impact absorption members are required to have improved impact energy absorption capacity at the time of a collision, that is, improved impact absorption capacity. Impact energy is absorbed by plastic deformation of the structural member. Therefore, in order to improve the impact absorption ability, it is effective to exhibit excellent plastic deformation ability even when subjected to high stress.
　本発明者らは、熱間プレス成形時における素材の冷却速度を低減できれば、素材が、高い応力を受けた場合にも優れた塑性変形能を発揮できると考えた。そこで、本発明者らは、金型の成形面の表面形状について検討した。その結果、本発明者らは、複数のリブ部と複数の溝部とを含む緩冷却領域を成形面に形成すれば、熱間プレス成形時の素材の冷却速度を低減できると考えた。 The inventors thought that if the cooling rate of the material during hot press molding could be reduced, the material would be able to exhibit excellent plastic deformability even when subjected to high stress. Therefore, the present inventors investigated the surface shape of the molding surface of the mold. As a result, the present inventors considered that the cooling rate of the material during hot press-forming can be reduced by forming a slow-cooling region including a plurality of ribs and a plurality of grooves on the molding surface.
　成形面においてリブ部は、所定方向に延在しており、延在方向と垂直な断面が凸形状を有する。成形面において溝部は、リブ部の延在方向に沿って延在しており、延在方向と垂直な断面が凹形状を有する。複数のリブ部と複数の溝部とは、交互に形成されている。 On the molding surface, the rib portion extends in a predetermined direction, and has a convex cross section perpendicular to the extending direction. On the molding surface, the groove extends along the extending direction of the rib, and has a concave cross section perpendicular to the extending direction. The plurality of rib portions and the plurality of groove portions are alternately formed.
　熱間プレス成形時において、緩冷却領域では、リブ部が素材に直接接触して素材を抜熱する。一方、溝部は、素材と直接接触しない。したがって、成形面が複数のリブ部と複数の溝部とを含んでいれば、熱間プレス成形時において、金型と素材とが接触する面積を減らすことができる。そのため、焼入れ時の素材の冷却速度を低減できる。 During hot press forming, the rib part directly contacts the material in the slow cooling region to remove heat from the material. On the other hand, the groove does not come into direct contact with the material. Therefore, if the molding surface includes a plurality of ribs and a plurality of grooves, it is possible to reduce the contact area between the mold and the material during hot press molding. Therefore, the cooling rate of the material during quenching can be reduced.
　以上の知見に基づいて、本発明者らは、金型の成形面の緩冷却領域中の複数のリブ部及び複数の溝部のうち、リブ部の幅と溝部の幅とに着目して、さらに詳細に検討した。その結果、リブ部の幅を、溝部の幅よりも狭くすれば、熱間プレス成形時の素材の抜熱が有効に低減し、冷却速度を低減できることを、本発明者らは知見した。熱間プレス成形時の素材の冷却速度を遅くできれば、素材の高強度化を抑制でき、衝撃吸収能を高めることができる。 Based on the above knowledge, the present inventors focused on the width of the rib and the width of the groove among the plurality of ribs and the plurality of grooves in the slow cooling region of the molding surface of the mold, and further examined in detail. As a result, the present inventors have found that if the width of the rib portion is narrower than the width of the groove portion, heat dissipation from the material during hot press forming can be effectively reduced, and the cooling rate can be reduced. If the cooling rate of the material during hot press molding can be slowed down, the increase in strength of the material can be suppressed, and the impact absorption capacity can be enhanced.
　緩冷却領域中のリブ部の幅を、溝部の幅よりも狭くすれば、熱間プレス成形品の少なくとも一部に、強度が低減された衝撃緩衝領域を形成することができる。しかしながら、リブ部の幅を溝部の幅よりも狭くしたとき、熱間プレス成形品の表面に波状の変形が生じ、熱間プレス成形品の寸法精度が低下する場合があった。そこで、本発明者らは、この原因について検討を行った。その結果、本発明者らは次の知見を得た。 By making the width of the rib portion in the slow cooling region narrower than the width of the groove portion, it is possible to form an impact buffering region with reduced strength in at least a portion of the hot press-formed product. However, when the width of the rib portion is narrower than the width of the groove portion, wavy deformation occurs on the surface of the hot press-formed product, which may reduce the dimensional accuracy of the hot press-formed product. Therefore, the present inventors investigated the cause of this. As a result, the present inventors obtained the following findings.
　熱間プレス成形時において、一対の金型（上型、下型）のうちの一方の金型の成形面の緩冷却領域に形成されたリブ部が、他方の金型の成形面の緩冷却領域に形成された溝部に入り込んでしまう場合がある。この場合、熱間プレス成形品の表面に、上述の波状の変形が生じる。 During hot press molding, the ribs formed in the slow cooling region of the molding surface of one of the pair of molds (upper mold, lower mold) cool the molding surface of the other mold. It may enter the groove formed in the region. In this case, the above-described wavy deformation occurs on the surface of the hot press-formed product.
　以上の知見に基づいて、本発明者らは、熱間プレス成形時において、一方の金型の緩冷却領域に形成されたリブ部と、他方の金型の緩冷却領域に形成されたリブ部とを、緩冷却領域の法線方向から見たときに重複させることを考えた。一方の金型の緩冷却領域に形成されたリブ部のうち少なくとも一部が、他方の金型の緩冷却領域に形成されたリブ部と重複すれば、リブ部が溝部に入り込んでしまうのを抑制することができる。 Based on the above knowledge, the present inventors have found that during hot press molding, the rib portion formed in the slow cooling region of one mold and the rib portion formed in the slow cooling region of the other mold and overlap when viewed from the normal direction of the slow cooling region. If at least a part of the rib formed in the slow cooling region of one mold overlaps with the rib formed in the slow cooling region of the other mold, the rib can be prevented from entering the groove. can be suppressed.
　本実施形態による金型では、熱間プレス成形時において、緩冷却領域を緩冷却領域の法線方向から見たとき、一方の緩冷却領域に形成されたリブ部と、他方の緩冷却領域に形成されたリブ部とは、少なくとも一部が重複する。その結果、リブ部の幅が溝部の幅よりも狭いことにより生じる、上述の波状の変形を抑制することができる。 In the mold according to the present embodiment, when the slow cooling region is viewed from the normal direction of the slow cooling region during hot press molding, the rib portion formed in one slow cooling region and the other slow cooling region At least a part overlaps with the formed rib portion. As a result, it is possible to suppress the above-described wavy deformation caused by the width of the rib portion being narrower than the width of the groove portion.
　以上の知見に基づいて完成した本実施形態による金型、及び、本実施形態による金型を用いた熱間プレス成形品の製造方法は、次の構成を備える。 The mold according to the present embodiment completed based on the above knowledge and the method for manufacturing a hot press-formed product using the mold according to the present embodiment have the following configurations.
　［１］
　素材に対して熱間プレス成形を実施するための金型であって、
　第１成形面を有する上型と、
　熱間プレス成形時において、前記第１成形面と対向して配置され、前記第１成形面とともに前記素材を熱間プレス成形する第２成形面を有する下型とを備え、
　前記第１成形面は、
　複数の第１リブ部と複数の第１溝部とを有する第１緩冷却領域を含み、
　複数の前記第１リブ部は、前記第１リブ部の幅方向に配列され、
　複数の前記第１溝部は、前記第１溝部の幅方向に配列され、
　前記第１リブ部は、隣り合う前記第１溝部の間に形成されており、
　前記第１リブ部の幅は、前記第１溝部の幅よりも狭く、
　前記第２成形面は、
　複数の第２リブ部と複数の第２溝部とを有する第２緩冷却領域を含み、
　複数の前記第２リブ部は、前記第２リブ部の幅方向に配列され、
　複数の前記第２溝部は、前記第２溝部の幅方向に配列され、
　前記第２リブ部は、隣り合う前記第２溝部の間に形成されており、
　前記第２リブ部の幅は、前記第２溝部の幅よりも狭く、
　熱間プレス成形時において、前記第１緩冷却領域及び前記第２緩冷却領域を、前記第１緩冷却領域の法線方向から見たとき、
　前記第１リブ部と前記第２リブ部とは、少なくとも一部が重複している、
　金型。 [1]
A mold for performing hot press molding on a material,
an upper mold having a first molding surface;
a lower mold having a second molding surface that is arranged to face the first molding surface and hot press molds the material together with the first molding surface during hot press molding;
The first molding surface is
including a first slow cooling region having a plurality of first ribs and a plurality of first grooves;
The plurality of first rib portions are arranged in the width direction of the first rib portion,
The plurality of first grooves are arranged in the width direction of the first grooves,
The first rib portion is formed between the adjacent first groove portions,
The width of the first rib portion is narrower than the width of the first groove portion,
The second molding surface is
including a second slow cooling region having a plurality of second ribs and a plurality of second grooves;
The plurality of second rib portions are arranged in the width direction of the second rib portion,
The plurality of second grooves are arranged in the width direction of the second grooves,
The second rib portion is formed between the adjacent second groove portions,
The width of the second rib portion is narrower than the width of the second groove portion,
During hot press forming, when the first slow cooling region and the second slow cooling region are viewed from the normal direction of the first slow cooling region,
At least a portion of the first rib portion and the second rib portion overlap,
Mold.
　［１］の金型は、熱間プレス成形によって、優れた衝撃吸収能を有する熱間プレス成形品を製造できる。 The mold of [1] can produce a hot press-formed product with excellent impact absorption capability by hot press-forming.
　［２］
　［１］に記載の金型であって、
　熱間プレス成形時において、前記第１緩冷却領域及び前記第２緩冷却領域を、前記第１緩冷却領域の法線方向から見たとき、
　前記第１リブ部と前記第２リブ部とは、同じ方向に延びており、
　前記第１溝部と前記第２溝部とは、同じ方向に延びている、
　金型。 [2]
The mold according to [1],
During hot press forming, when the first slow cooling region and the second slow cooling region are viewed from the normal direction of the first slow cooling region,
The first rib portion and the second rib portion extend in the same direction,
The first groove and the second groove extend in the same direction,
Mold.
　［２］の金型は、熱間プレス成形時の素材における熱伝達のシミュレーションの精度を高めることができる。 The mold of [2] can improve the accuracy of the simulation of heat transfer in the material during hot press molding.
　［３］
　［１］又は［２］に記載の金型であって、
　前記第１リブ部の幅は、前記第１溝部の幅の１０～５０％であり、
　前記第２リブ部の幅は、前記第２溝部の幅の１０～５０％である、
　金型。 [3]
The mold according to [1] or [2],
The width of the first rib portion is 10 to 50% of the width of the first groove portion,
The width of the second rib portion is 10 to 50% of the width of the second groove portion,
Mold.
　［３］の金型であれば、熱間プレス成形時において、冷却速度を遅くすることができる。冷却速度を遅くすることができれば、所望の素材温度で冷却を停止しやすくなる。例えば、熱間プレス成形時においてＭｆ点～Ｍｓ点の間で冷却を停止して、その後に後述する加熱保持工程を実施することにより、素材のミクロ組織中のマルテンサイト、及び、残留オーステナイトの生成量を調整してもよい。また、例えば、熱間プレス成形時においてＭｓ点超～５００℃の間の温度で冷却を停止して、かつ、その後に後述する加熱保持工程を実施することにより、素材のミクロ組織をベイナイト主体の組織としてもよい。 With the mold of [3], the cooling rate can be slowed during hot press molding. If the cooling rate can be slowed down, it becomes easier to stop cooling at a desired material temperature. For example, during hot press forming, cooling is stopped between the Mf point and the Ms point, and then the heating and holding step described later is performed to generate martensite and retained austenite in the microstructure of the material. You can adjust the amount. Further, for example, during hot press molding, cooling is stopped at a temperature between Ms point and 500 ° C., and then a heating and holding step described later is performed, so that the microstructure of the material is mainly bainite. It can be an organization.
　［４］
　［１］～［３］のいずれか１つに記載の金型であって、
　前記第１緩冷却領域の少なくとも一部において、
　前記第１リブ部の幅は、１．０～８．０ｍｍであり、
　前記第１リブ部の高さは、０．２～５．０ｍｍであり、
　前記第２緩冷却領域の少なくとも一部において、
　前記第２リブ部の幅は、１．０～８．０ｍｍであり、
　前記第２リブ部の高さは、０．２～５．０ｍｍである、
　金型。 [4]
The mold according to any one of [1] to [3],
In at least part of the first slow cooling region,
The width of the first rib portion is 1.0 to 8.0 mm,
The height of the first rib portion is 0.2 to 5.0 mm,
In at least part of the second slow cooling region,
The width of the second rib portion is 1.0 to 8.0 mm,
The height of the second rib portion is 0.2 to 5.0 mm,
Mold.
　［４］の金型は、熱間プレス成形時の素材の温度ばらつきを抑制できる。 The mold of [4] can suppress the temperature variation of the material during hot press molding.
　［５］
　［２］に記載の金型であって、
　前記第１リブ部の幅は、前記第１溝部の幅の１０～５０％であり、
　前記第２リブ部の幅は、前記第２溝部の幅の１０～５０％であり、
　前記第１リブ部及び前記第２リブ部の各々の幅は１．０～８．０ｍｍであり、
　前記第１リブ部及び前記第２リブ部の各々の高さは０．２～５．０ｍｍであり、
　式（１）で定義されるＦｎ１が１４以下である、
　金型。
　Ｆｎ１＝Ｗｒ０．９／Ｐ００．８＋０．０５Ｈｒ　（１）
　ここで、式（１）中のＷｒは前記第１リブ部及び前記第２リブ部の幅（ｍｍ）であり、Ｐ０＝Ｗｒ／Ｗｓであり、Ｗｓは前記第１溝部及び前記第２溝部の幅（ｍｍ）であり、Ｈｒは前記第１リブ部及び前記第２リブ部の高さ（ｍｍ）である。 [5]
The mold according to [2],
The width of the first rib portion is 10 to 50% of the width of the first groove portion,
The width of the second rib portion is 10 to 50% of the width of the second groove portion,
The width of each of the first rib portion and the second rib portion is 1.0 to 8.0 mm,
Each height of the first rib portion and the second rib portion is 0.2 to 5.0 mm,
Fn1 defined by formula (1) is 14 or less,
Mold.
Fn1= Wr0.9 / P00.8 +0.05Hr (1)
Here, Wr in the formula (1) is the width (mm) of the first rib portion and the second rib portion, P0 = Wr/Ws, and Ws is the width of the first groove portion and the second groove portion. is the width (mm), and Hr is the height (mm) of the first rib portion and the second rib portion.
　［５］の金型では、熱間プレス成形時の素材の温度ばらつきをさらに抑制できる。 The mold of [5] can further suppress the temperature variation of the material during hot press molding.
　［６］
　［２］又は［５］に記載の金型であって、
　前記第１リブ部の幅は、前記第１溝部の幅の１０～５０％であり、
　前記第２リブ部の幅は、前記第２溝部の幅の１０～５０％であり、
　前記第１リブ部及び前記第２リブ部の各々の幅は１．０～８．０ｍｍであり、
　前記第１リブ部及び前記第２リブ部の各々の高さは０．２～５．０ｍｍであり、
　式（２）で定義されるＦｎ２が３０以上である、
　金型。
　Ｆｎ２＝Ｗｓ２×Ｈｒ０．４／Ｗｒ　（２）
　ここで、式（２）中のＷｓは前記第１溝部及び前記第２溝部の幅（ｍｍ）であり、Ｗｒは前記第１リブ部及び前記第２リブ部の幅（ｍｍ）であり、Ｈｒは前記第１リブ部及び前記第２リブ部の高さ（ｍｍ）である。 [6]
The mold according to [2] or [5],
The width of the first rib portion is 10 to 50% of the width of the first groove portion,
The width of the second rib portion is 10 to 50% of the width of the second groove portion,
The width of each of the first rib portion and the second rib portion is 1.0 to 8.0 mm,
Each height of the first rib portion and the second rib portion is 0.2 to 5.0 mm,
Fn2 defined by formula (2) is 30 or more,
Mold.
Fn2=Ws2* Hr0.4 /Wr ( 2 )
Here, Ws in the formula (2) is the width (mm) of the first groove portion and the second groove portion, Wr is the width (mm) of the first rib portion and the second rib portion, and Hr is the height (mm) of the first rib portion and the second rib portion.
　［６］の金型では、素材の冷却速度をより遅くすることができる。冷却速度を遅くすることができれば、所望の素材温度で冷却をより停止しやすくなる。例えば、熱間プレス成形時においてＭｆ点～Ｍｓ点の間で冷却を停止して、その後に後述する加熱保持工程を実施することにより、素材のミクロ組織中のマルテンサイト、及び、残留オーステナイトの生成量を調整してもよい。また、例えば、熱間プレス成形時においてＭｓ点超～５００℃の間の温度で冷却を停止して、かつ、その後に後述する加熱保持工程を実施することにより、素材のミクロ組織をベイナイト主体の組織としてもよい。 With the mold of [6], the cooling speed of the material can be made slower. If the cooling rate can be slowed down, it becomes easier to stop cooling at the desired material temperature. For example, during hot press forming, cooling is stopped between the Mf point and the Ms point, and then the heating and holding step described later is performed to generate martensite and retained austenite in the microstructure of the material. You can adjust the amount. Further, for example, during hot press molding, cooling is stopped at a temperature between Ms point and 500 ° C., and then a heating and holding step described later is performed, so that the microstructure of the material is mainly bainite. It can be an organization.
　［７］
　［４］～［６］のいずれか１項に記載の金型であって、
　前記第１緩冷却領域の少なくとも一部において、
　前記第１リブ部の幅は、１．０～４．０ｍｍであり、かつ、前記第１溝部の幅の１０～３０％であり、
　前記第２緩冷却領域の少なくとも一部において、
　前記第２リブ部の幅は、１．０～４．０ｍｍであり、かつ、前記第２溝部の幅の１０～３０％である、
　金型。 [7]
The mold according to any one of [4] to [6],
In at least part of the first slow cooling region,
The width of the first rib portion is 1.0 to 4.0 mm and 10 to 30% of the width of the first groove portion,
In at least part of the second slow cooling region,
The width of the second rib portion is 1.0 to 4.0 mm, and 10 to 30% of the width of the second groove portion.
Mold.
　［７］の金型は、熱間プレス成形時の素材の温度ばらつきをさらに抑制できる。 The mold of [7] can further suppress the temperature variation of the material during hot press molding.
　［８］
　熱間プレス成形品の製造方法であって、
　素材を準備する工程と、
　前記準備された素材をＡｃ３点以上の温度に加熱する工程と、
　加熱された前記素材に対して、［１］～［７］のいずれか１項に記載の金型により熱間プレス成形を実施する工程と、
　熱間プレス成形された前記素材を、前記金型から離型して、熱間プレス成形品を製造する工程とを備える、
　熱間プレス成形品の製造方法。 [8]
A method for manufacturing a hot press-formed product,
a process of preparing materials;
heating the prepared material to a temperature of A c 3 or higher;
A step of performing hot press molding on the heated material using the mold according to any one of [1] to [7];
A step of releasing the hot press-formed material from the mold to produce a hot press-formed product;
A method for producing a hot press-formed product.
　［８］の熱間プレス成形品の製造方法は、優れた衝撃吸収能を有する熱間プレス成形品を製造できる。 The method for producing a hot press-formed product in [8] can produce a hot press-formed product with excellent impact absorption capability.
　［９］
　［８］に記載の熱間プレス成形品の製造方法であってさらに、
　前記金型から離型して製造された前記熱間プレス成形品を、１００～５００℃で保持する工程とを備える、
　熱間プレス成形品の製造方法。 [9]
The method for producing a hot press-formed product according to [8], further comprising:
A step of holding the hot press-formed product produced by releasing from the mold at 100 to 500 ° C.
A method for producing a hot press-formed product.
　以下、本実施形態による金型、及び、本実施形態による金型を用いた熱間プレス成形品の製造方法について、図面を参照して説明する。なお、各図面において同一又は相当する構成については、同一の符号を付し、同一の説明を繰り返さない。 The mold according to this embodiment and the method for manufacturing a hot press-formed product using the mold according to this embodiment will be described below with reference to the drawings. In each drawing, the same or corresponding configurations are denoted by the same reference numerals, and the same description will not be repeated.
　［熱間プレス装置１の構成］
　図１は、熱間プレス成形用の熱間プレス装置１の一例を示す正面図である。図１を参照して、熱間プレス装置１は、本実施形態による金型１０を除き、公知の熱間プレス装置と実質的に同じ構成を備える。熱間プレス装置１は、フレーム２と、スライド３と、ボルスタ４と、金型１０（上型１１及び下型１２）とを備える。以降の説明において、熱間プレス装置１の鉛直方向（上下）方向をＶ方向、熱間プレス装置１の幅方向をＷ方向、Ｖ方向とＷ方向と垂直な方向をＬ方向ともいう。 [Configuration of hot press device 1]
FIG. 1 is a front view showing an example of a hot press machine 1 for hot press molding. Referring to FIG. 1, a hot press machine 1 has substantially the same configuration as a known hot press machine, except for a mold 10 according to this embodiment. A hot press device 1 includes a frame 2, a slide 3, a bolster 4, and a die 10 (upper die 11 and lower die 12). In the following description, the vertical (vertical) direction of the hot press machine 1 is also called the V direction, the width direction of the hot press machine 1 is also called the W direction, and the V direction and the direction perpendicular to the W direction are also called the L direction.
　図１を参照して、フレーム２は、熱間プレス装置１の上部に配置される。フレーム２は、フレーム２の下方に配置されるスライド３を昇降可能に支持する。フレーム２は、スライド３を昇降する駆動装置（図示せず）を備える。駆動装置は機械式機構であってもよいし、液圧式機構であってもよい。スライド３は、フレーム２に取り付けられ、フレーム２が備える駆動装置により上下方向に昇降可能である。スライド３の下面には、上型１１が取り付けられる。ボルスタ４は、スライド３の下方に配置される。ボルスタ４の上面は、スライド３の下面と対向する。ボルスタ４の上面には、下型１２が取り付けられる。このとき、下型１２は、上型１１の下方に配置される。 With reference to FIG. 1, the frame 2 is arranged on the upper part of the hot press device 1. The frame 2 supports a slide 3 arranged below the frame 2 so as to be able to move up and down. The frame 2 has a drive (not shown) for raising and lowering the slide 3 . The drive may be a mechanical mechanism or a hydraulic mechanism. The slide 3 is attached to the frame 2 and can be vertically moved by a driving device provided in the frame 2 . An upper die 11 is attached to the lower surface of the slide 3 . A bolster 4 is arranged below the slide 3 . The upper surface of bolster 4 faces the lower surface of slide 3 . A lower mold 12 is attached to the upper surface of the bolster 4 . At this time, the lower mold 12 is arranged below the upper mold 11 .
　金型１０は、上述の上型１１と、上述の下型１２とを含む。上型１１及び下型１２は、図１のＬ方向に延びている。以下、熱間プレス装置１及び金型１０に関して、上型１１及び下型１２が延びる方向を「金型１０の長手方向（Ｌ方向）」ともいう。金型１０に関して、Ｌ方向、及び、図１のＶ方向に垂直な方向を「金型１０の幅方向（Ｗ方向）」ともいう。 The mold 10 includes the upper mold 11 described above and the lower mold 12 described above. The upper die 11 and the lower die 12 extend in the L direction in FIG. Hereinafter, regarding the hot press device 1 and the die 10, the direction in which the upper die 11 and the lower die 12 extend is also referred to as "longitudinal direction (L direction) of the die 10". With respect to the mold 10, the L direction and the direction perpendicular to the V direction in FIG. 1 are also referred to as the "width direction (W direction) of the mold 10".
　上述のとおり、上型１１は、スライド３の下面に固定されており、下型１２は、ボルスタ４の上面に固定されている。そして、下型１２は上型１１の下方に配置されている。熱間プレス成形を実施するとき、初めに、加熱された素材（ブランク）が、下型１２上に配置される。素材の配置後、上型１１が下型１２に対して相対的にＶ方向にスライドして、素材に接触しながら、素材に外力を付与する。つまり、上型１１及び下型１２が素材を熱間プレス成形する。これにより、素材を所望の形状に成形する。さらに、熱間プレス成形中において、上型１１の成形面と下型１２の成形面とが素材と接触して、上型１１及び下型１２が素材を抜熱して焼入れする。そのため、所望の形状を有し、かつ、強度を高めた熱間プレス成形品が製造される。 As described above, the upper mold 11 is fixed to the lower surface of the slide 3 and the lower mold 12 is fixed to the upper surface of the bolster 4 . The lower mold 12 is arranged below the upper mold 11 . When performing hot press molding, first, a heated material (blank) is placed on the lower mold 12 . After placing the material, the upper die 11 slides in the V direction relative to the lower die 12 and applies an external force to the material while being in contact with the material. In other words, the upper mold 11 and the lower mold 12 hot press mold the material. Thereby, the material is formed into a desired shape. Furthermore, during hot press molding, the molding surface of the upper mold 11 and the molding surface of the lower mold 12 come into contact with the material, and the upper mold 11 and the lower mold 12 remove heat from the material and harden it. Therefore, a hot press-formed product having a desired shape and enhanced strength is manufactured.
　熱間プレス装置１は、図１に図示しない構成を含んでいてもよい。熱間プレス装置１は、例えば、金型１０を冷却するための冷却装置を備えてもよい。この場合、例えば、金型１０内部に、冷却媒体が通る流路が設けられる。さらに、金型１０内部に冷却媒体を供給するためのポンプが配置される。熱間プレス装置１はさらに、熱間プレス装置１に素材を搬送するための搬送機構を備えてもよい。熱間プレス装置１は、図１に図示されない構成であって、公知の熱間プレス装置が備える構成を備えてもよい。 The hot press device 1 may include a configuration not shown in FIG. The hot press device 1 may include, for example, a cooling device for cooling the mold 10 . In this case, for example, a flow path through which the cooling medium passes is provided inside the mold 10 . Furthermore, a pump for supplying a cooling medium inside the mold 10 is arranged. The hot press device 1 may further include a transport mechanism for transporting the material to the hot press device 1 . The hot press device 1 may have a configuration not shown in FIG. 1, which is provided in a known hot press device.
　［金型１０の構成］
　図１中の金型１０の構成について、さらに詳細に説明する。
　図２は、図１中の金型１０の斜視図である。図２を参照して、上型１１は、第１成形面１１０を有する。第１成形面１１０は、上型１１の下面に配置されている。図２では、第１成形面１１０は、Ｗ方向中央部に、Ｌ方向に延びる凹部を含む。 [Configuration of mold 10]
The configuration of the mold 10 in FIG. 1 will be described in more detail.
FIG. 2 is a perspective view of the mold 10 in FIG. 1. FIG. Referring to FIG. 2, upper mold 11 has first molding surface 110 . The first molding surface 110 is arranged on the lower surface of the upper mold 11 . In FIG. 2, the first molding surface 110 includes a concave portion extending in the L direction in the central portion in the W direction.
　下型１２は、第２成形面１２０を有する。第２成形面１２０は、下型１２の上面に配置されている。図２では、第２成形面１２０は、Ｗ方向の中央部に、Ｌ方向に延びる凸部を含む。熱間プレス成形時において、第２成形面１２０は、第１成形面１１０と対向して配置される。そして、第２成形面１２０は、第１成形面１１０とともに、素材（ブランク）と接触して、素材を熱間プレス成形する。 The lower mold 12 has a second molding surface 120. The second molding surface 120 is arranged on the upper surface of the lower mold 12 . In FIG. 2, the second molding surface 120 includes a convex portion extending in the L direction at the central portion in the W direction. During hot press molding, the second molding surface 120 is arranged to face the first molding surface 110 . The second molding surface 120 and the first molding surface 110 are brought into contact with the material (blank) to hot press mold the material.
　［第１成形面１１０及び第２成形面１２０の構成］
　第１成形面１１０は、斜線部で示す第１緩冷却領域１１３を含む。図２では、第１緩冷却領域１１３は、第１成形面１１０の一部に形成される。図２では、第１成形面１１０は、第１緩冷却領域１１３と、第１急冷領域１１４とを含む。
　同様に、第２成形面１２０は、斜線部で示す第２緩冷却領域１２３を含む。図２では、第２緩冷却領域１２３は、第２成形面１２０の一部に形成される。図２では、第２成形面１２０は、第２緩冷却領域１２３と、第２急冷領域１２４とを含む。
　熱間プレス成形時において、第１急冷領域１１４は、第２急冷領域１２４と対向する。第１急冷領域１１４と、第２急冷領域１２４とは、熱間プレス成形後の素材（熱間プレス成形品）に、高強度を有する高強度領域を形成する。
　熱間プレス成形時において、第１緩冷却領域１１３は、第２緩冷却領域１２３と対向する。第１緩冷却領域１１３と、第２緩冷却領域１２３とは、熱間プレス成形後の素材（熱間プレス成形品）に、高強度領域よりも強度が低く、塑性変形しやすい衝撃緩衝領域を形成する。 [Configuration of First Molding Surface 110 and Second Molding Surface 120]
The first molding surface 110 includes a first slow cooling region 113 indicated by hatching. In FIG. 2 , the first slow cooling region 113 is formed on a portion of the first molding surface 110 . In FIG. 2, first forming surface 110 includes first slow cooling region 113 and first quenching region 114 .
Similarly, the second molding surface 120 includes a second slow cooling region 123 indicated by hatching. In FIG. 2 , the second slow cooling region 123 is formed on a portion of the second molding surface 120 . In FIG. 2, second molding surface 120 includes second slow cooling region 123 and second quenching region 124 .
During hot press forming, the first quench zone 114 faces the second quench zone 124 . The first rapid cooling region 114 and the second rapid cooling region 124 form high-strength regions having high strength in the material (hot press-formed product) after hot press-forming.
During hot press forming, the first slow cooling region 113 faces the second slow cooling region 123 . The first slow-cooling region 113 and the second slow-cooling region 123 are impact-absorbing regions that have a lower strength than the high-strength region and are prone to plastic deformation in the material (hot press-formed product) after hot press forming. Form.
　図３は、熱間プレス成形時の第１緩冷却領域１１３及び第２緩冷却領域１２３における、金型１０及び素材（ブランク）Ｂの状態を示す、Ｖ方向及びＷ方向を含む断面図である。図４は、熱間プレス成形時の第１急冷領域１１４及び第２急冷領域１２４における、金型１０及び素材Ｂの状態を示す、Ｖ方向及びＷ方向を含む断面図である。図３及び図４は、上型１１が下死点に到達し、金型１０が閉じた状態を示す。換言すれば、図３及び図４は、上型１１の第１成形面１１０の略全体と、下型１２の第２成形面１２０の略全体とが、素材Ｂと接触して、素材Ｂに外力を付与している状態を示す。 FIG. 3 is a cross-sectional view including the V direction and the W direction showing the state of the mold 10 and the material (blank) B in the first slow cooling region 113 and the second slow cooling region 123 during hot press molding. . FIG. 4 is a cross-sectional view including the V direction and the W direction showing the state of the mold 10 and the material B in the first quenching region 114 and the second quenching region 124 during hot press molding. 3 and 4 show the state in which the upper mold 11 reaches the bottom dead center and the mold 10 is closed. In other words, FIGS. 3 and 4 show that substantially the entire first molding surface 110 of the upper mold 11 and substantially the entire second molding surface 120 of the lower mold 12 are in contact with the material B, and are attached to the material B. It shows the state in which an external force is applied.
　図２～図４を参照して、熱間プレス成形時において、素材Ｂは上型１１と下型１２とに挟まれる。このとき、第１成形面１１０の凹部が、第２成形面１２０の凸部内に嵌合する。その結果、素材Ｂは、ハット型の熱間プレス成形品に成形される。 With reference to FIGS. 2 to 4, material B is sandwiched between upper mold 11 and lower mold 12 during hot press molding. At this time, the concave portion of the first molding surface 110 fits into the convex portion of the second molding surface 120 . As a result, the material B is formed into a hat-shaped hot press-formed product.
　図２の金型１０はさらに、緩冷却領域（１１３及び１２３）と、急冷領域（１１４及び１２４）とを含む。上型１１の第１成形面１１０では、熱間プレス成形品の衝撃緩衝領域を形成する第１緩冷却領域１１３の表面構造は、熱間プレス成形品の高強度領域を形成する第１急冷領域１１４の表面構造と異なる。同様に、下型１２の第２成形面１２０では、熱間プレス成形品の衝撃緩衝領域を形成する第２緩冷却領域１２３の表面構造は、熱間プレス成形品の高強度領域を形成する第２急冷領域１２４の表面構造と異なる。以下、第１成形面１１０及び第２成形面１２０の表面構造についてさらに説明する。 The mold 10 of FIG. 2 further includes slow cooling regions (113 and 123) and rapid cooling regions (114 and 124). On the first molding surface 110 of the upper mold 11, the surface structure of the first slow cooling region 113 forming the impact buffering region of the hot press-formed product is the same as that of the first rapid cooling region forming the high-strength region of the hot press-formed product. 114 surface structure. Similarly, on the second molding surface 120 of the lower die 12, the surface structure of the second slow-cooling region 123 forming the impact buffering region of the hot press-formed product is different from that of the second slow cooling region 123 forming the high-strength region of the hot press-formed product. 2 different from the surface structure of the quench zone 124; The surface structures of the first molding surface 110 and the second molding surface 120 are further described below.
　［第１成形面１１０の構成］
　［第１緩冷却領域１１３の構成］
　図５Ａは、図３中の第１成形面１１０の第１緩冷却領域１１３内の領域１００の拡大図である。図５Ａを参照して、上型１１の第１成形面１１０の第１緩冷却領域１１３は、複数の第１リブ部１１１と、複数の第１溝部１１２とを有する。図６は、図３の領域１００を上方向（第１緩冷却領域１１３及び第２緩冷却領域１２３の法線方向）から見た、領域１００の模式図である。図５Ａ及び図６を参照して、複数の第１リブ部１１１は、所定の方向に延在している。図５Ａ及び図６では、一例として、複数の第１リブ部１１１は、Ｌ方向に延びている。ただし、複数の第１リブ部１１１の延在方向は、Ｌ方向に限定されない。 [Configuration of first molding surface 110]
[Configuration of first slow cooling region 113]
5A is an enlarged view of the region 100 within the first slow cooling region 113 of the first molding surface 110 in FIG. 3. FIG. Referring to FIG. 5A , first slow cooling region 113 of first molding surface 110 of upper mold 11 has a plurality of first rib portions 111 and a plurality of first groove portions 112 . FIG. 6 is a schematic diagram of the region 100 of FIG. 3 as viewed from above (the normal direction of the first slow cooling region 113 and the second slow cooling region 123). 5A and 6, the plurality of first rib portions 111 extend in a predetermined direction. In FIGS. 5A and 6, as an example, the multiple first rib portions 111 extend in the L direction. However, the extending direction of the plurality of first rib portions 111 is not limited to the L direction.
　複数の第１リブ部１１１は、第１リブ部１１１の幅方向に配列される。第１リブ部１１１の幅方向とは、第１リブ部１１１の延在方向に垂直な方向である。図５Ａでは、第１リブ部１１１の幅方向は、Ｗ方向である。しかしながら、第１リブ部１１１の幅方向はＷ方向に限定されない。本実施形態では、各第１リブ部１１１が、Ｌ方向に延在し、Ｗ方向に配列される。 The plurality of first rib portions 111 are arranged in the width direction of the first rib portions 111 . The width direction of the first rib portion 111 is a direction perpendicular to the extending direction of the first rib portion 111 . In FIG. 5A, the width direction of the first rib portion 111 is the W direction. However, the width direction of the first rib portion 111 is not limited to the W direction. In this embodiment, each first rib portion 111 extends in the L direction and is arranged in the W direction.
　図５Ａを参照して、複数の第１溝部１１２は、第１溝部１１２の幅方向に配列され、第１リブ部１１１は、隣り合う第１溝部１１２の間に形成される。図５Ａでは、第１溝部１１２は、第１リブ部１１１と同様に、Ｌ方向に延在し、Ｗ方向に配列される。さらに、第１リブ部１１１は、隣り合う２つの第１溝部１１２の間に形成される。図５Ａでは、複数の第１溝部１１２と複数の第１リブ部１１１とがいずれもＬ方向に延在し、第１溝部１１２と第１リブ部１１１とがＷ方向に交互に並んでいる。 5A, the plurality of first grooves 112 are arranged in the width direction of the first grooves 112, and the first ribs 111 are formed between adjacent first grooves 112. As shown in FIG. In FIG. 5A, the first grooves 112 extend in the L direction and are arranged in the W direction, like the first ribs 111 . Furthermore, the first rib portion 111 is formed between two adjacent first groove portions 112 . 5A, the plurality of first grooves 112 and the plurality of first ribs 111 both extend in the L direction, and the first grooves 112 and the first ribs 111 are alternately arranged in the W direction.
　図５Ａを参照して、第１リブ部１１１の幅は、第１溝部１１２の幅よりも狭い。上述のとおり、第１リブ部１１１の幅とは、第１リブ部１１１の延在方向に垂直な断面での第１リブ部１１１の幅を意味する。図５Ａでは、第１リブ部１１１の幅は、第１リブ部１１１のＷ方向の幅を意味する。同様に、第１溝部１１２の幅とは、第１溝部１１２の延在方向に垂直な断面での第１溝部１１２の幅を意味する。図５Ａでは、第１溝部１１２の幅は、第１溝部１１２のＷ方向の幅を意味する。第１リブ部１１１の幅及び第１溝部１１２の幅は、例えば、ノギス等を用いて、容易に求めることができる。 Referring to FIG. 5A, the width of first rib portion 111 is narrower than the width of first groove portion 112 . As described above, the width of the first rib portion 111 means the width of the first rib portion 111 in a cross section perpendicular to the extending direction of the first rib portion 111 . In FIG. 5A, the width of the first rib portion 111 means the width of the first rib portion 111 in the W direction. Similarly, the width of the first groove portion 112 means the width of the first groove portion 112 in a cross section perpendicular to the extending direction of the first groove portion 112 . In FIG. 5A, the width of the first groove portion 112 means the width of the first groove portion 112 in the W direction. The width of the first rib portion 111 and the width of the first groove portion 112 can be easily determined using, for example, vernier calipers.
　図５Ａを参照して、本実施形態では、第１リブ部１１１の幅が第１溝部１１２の幅よりも狭い。熱間プレス成形時に第１緩冷却領域１１３が素材Ｂと接触したとき、第１溝部１１２での抜熱量は、第１リブ部１１１での抜熱量よりも少ない。第１リブ部１１１の幅は、第１溝部１１２の幅よりも狭いため、第１リブ部１１１での抜熱量をより少なく抑えることができる。そのため、第１緩冷却領域１１３では、第１急冷領域１１４と比較して、素材Ｂの冷却速度を遅くすることができる。そのため、金型１０を用いて熱間プレス成形を実施した場合、素材Ｂのうち、第１緩冷却領域１１３に接触した領域の焼入れの度合いを低減できる。その結果、熱間プレス成形後の素材Ｂ（熱間プレス成形品）に、強度を抑えた衝撃緩衝領域を形成することができる。 Referring to FIG. 5A, in the present embodiment, the width of first rib portion 111 is narrower than the width of first groove portion 112 . When the first slow-cooling region 113 comes into contact with the material B during hot press-forming, the heat removal amount in the first groove portion 112 is smaller than the heat removal amount in the first rib portion 111 . Since the width of the first rib portion 111 is narrower than the width of the first groove portion 112, the amount of heat removal in the first rib portion 111 can be reduced. Therefore, in the first slow cooling region 113 , the cooling rate of the material B can be made slower than in the first rapid cooling region 114 . Therefore, when hot press molding is performed using the mold 10, the degree of quenching of the region of the material B that is in contact with the first slow cooling region 113 can be reduced. As a result, the material B (hot press-formed product) after hot press-forming can be formed with a shock absorbing region with reduced strength.
　［第１急冷領域１１４の構成］
　図７は、図４の第１成形面１１０の第１急冷領域１１４中の領域２００の拡大図である。図７を参照して、上型１１の第１成形面１１０の第１急冷領域１１４では、第１リブ部１１１及び第１溝部１１２は形成されていない。換言すれば、第１成形面１１０の第１急冷領域１１４は、滑らかな面である。そのため、熱間プレス成形時において、第１急冷領域１１４の略全体が、素材Ｂと接触する。そのため、第１急冷領域１１４では、第１緩冷却領域１１３と比較して、素材Ｂの冷却速度を速くすることができる。そのため、金型１０を用いて熱間プレス成形が実施された場合、素材Ｂのうち、第１急冷領域１１４に接触した領域の焼入れの度合いを高めることができる。その結果、熱間プレス成形後の素材Ｂ（熱間プレス成形品）に、衝撃緩衝領域よりも強度の高い高強度領域を形成することができる。 [Configuration of first quenching region 114]
FIG. 7 is an enlarged view of area 200 in first quench zone 114 of first forming surface 110 of FIG. Referring to FIG. 7 , first rib portion 111 and first groove portion 112 are not formed in first rapid cooling region 114 of first molding surface 110 of upper mold 11 . In other words, the first quench region 114 of the first molding surface 110 is a smooth surface. Therefore, substantially the entire first quench region 114 is in contact with the material B during hot press forming. Therefore, in the first rapid cooling region 114 , the cooling rate of the material B can be made faster than in the first slow cooling region 113 . Therefore, when hot press forming is performed using the mold 10, the degree of quenching of the area of the material B that is in contact with the first rapid cooling area 114 can be increased. As a result, it is possible to form a high-strength region having a higher strength than the impact buffer region in the material B (hot press-formed product) after hot press-forming.
　［第２成形面１２０の構成］
　［第２緩冷却領域１２３の構成］
　図５Ａを参照して、下型１２の第２成形面１２０の第２緩冷却領域１２３は、複数の第２リブ部１２１と、複数の第２溝部１２２とを有する。図５Ａ及び図６を参照して、複数の第２リブ部１２１は、所定の方向に延在している。図５Ａ及び図６では、複数の第２リブ部１２１は、Ｌ方向に延びている。ただし、複数の第２リブ部１２１の延在方向は、Ｌ方向に限定されない。 [Configuration of second molding surface 120]
[Configuration of the second slow cooling region 123]
Referring to FIG. 5A , second slow cooling region 123 of second molding surface 120 of lower die 12 has a plurality of second rib portions 121 and a plurality of second groove portions 122 . 5A and 6, the plurality of second rib portions 121 extend in a predetermined direction. 5A and 6, the plurality of second rib portions 121 extend in the L direction. However, the extending direction of the plurality of second rib portions 121 is not limited to the L direction.
　複数の第２リブ部１２１は、第２リブ部１２１の幅方向に配列される。第２リブ部１２１の幅方向とは、第２リブ部１２１の延在方向に垂直な方向である。図５Ａでは、第２リブ部１２１の幅方向は、Ｗ方向である。しかしながら、第２リブ部１２１の幅方向はＷ方向に限定されない。本実施形態では、各第２リブ部１２１が、Ｌ方向に延在し、Ｗ方向に配列される。 The plurality of second rib portions 121 are arranged in the width direction of the second rib portions 121 . The width direction of the second rib portion 121 is a direction perpendicular to the extending direction of the second rib portion 121 . In FIG. 5A, the width direction of the second rib portion 121 is the W direction. However, the width direction of the second rib portion 121 is not limited to the W direction. In this embodiment, the second rib portions 121 extend in the L direction and are arranged in the W direction.
　図５Ａを参照して、複数の第２溝部１２２は、第２溝部１２２の幅方向に配列され、第２リブ部１２１は、隣り合う第２溝部１２２の間に形成される。図５Ａでは、第２溝部１２２は、第２リブ部１２１と同様に、Ｌ方向に延在し、Ｗ方向に配列される。さらに、第２リブ部１２１は、隣り合う２つの第２溝部１２２の間に形成される。図５Ａでは、複数の第２溝部１２２と複数の第２リブ部１２１とがいずれもＬ方向に延在し、第２溝部１２２と第２リブ部１２１とがＷ方向に交互に並んでいる。 5A, the plurality of second grooves 122 are arranged in the width direction of the second grooves 122, and the second ribs 121 are formed between the adjacent second grooves 122. As shown in FIG. In FIG. 5A, the second grooves 122 extend in the L direction and are arranged in the W direction, like the second ribs 121 . Furthermore, the second rib portion 121 is formed between two adjacent second groove portions 122 . In FIG. 5A, the plurality of second grooves 122 and the plurality of second ribs 121 both extend in the L direction, and the second grooves 122 and the second ribs 121 are alternately arranged in the W direction.
　図５Ａを参照して、さらに、第２リブ部１２１の幅は、第２溝部１２２の幅よりも狭い。上述のとおり、第２リブ部１２１及び第２溝部１２２の幅方向とは、金型１０の幅方向（Ｗ方向）に相当する。したがって、図５Ａに示される断面において、第２リブ部１２１の幅は、第２リブ部１２１のＷ方向の幅を意味し、第２溝部１２２の幅は、第２溝部１２２のＷ方向の幅を意味する。第２リブ部１２１の幅及び第２溝部１２２の幅は、例えば、ノギスを用いて求めることができる。 Further, with reference to FIG. 5A, the width of the second rib portion 121 is narrower than the width of the second groove portion 122 . As described above, the width direction of the second rib portion 121 and the second groove portion 122 corresponds to the width direction (W direction) of the mold 10 . Therefore, in the cross section shown in FIG. 5A, the width of the second rib portion 121 means the width of the second rib portion 121 in the W direction, and the width of the second groove portion 122 means the width of the second groove portion 122 in the W direction. means The width of the second rib portion 121 and the width of the second groove portion 122 can be determined using, for example, vernier calipers.
　図５Ａを参照して、第２リブ部１２１の幅が第２溝部１２２の幅よりも狭い。上述のとおり、第２リブ部１２１の幅とは、第２リブ部１２１の延在方向に垂直な断面での第２リブ部１２１の幅を意味する。そのため、上述の第１リブ部１１１の幅及び第１溝部１１２の幅の関係と同様の効果が得られる。具体的には、熱間プレス成形時に第２緩冷却領域１２３が素材Ｂと接触したとき、第２溝部１２２での抜熱量は、第２リブ部１２１での抜熱量よりも少ない。第２リブ部１２１の幅は、第２溝部１２２の幅よりも狭いため、第２リブ部１２１での抜熱量をより少なく抑えることができる。そのため、第２緩冷却領域１２３では、後述の第２急冷領域１２４と比較して、素材Ｂの冷却速度を遅くすることができる。そのため、金型１０を用いて熱間プレス成形が実施された場合、素材Ｂのうち、第２緩冷却領域１２３に接触した領域の焼入れの度合いを低減できる。その結果、熱間プレス成形後の素材Ｂ（熱間プレス成形品）に、強度を抑えた衝撃緩衝領域を形成することができる。 Referring to FIG. 5A, the width of second rib portion 121 is narrower than the width of second groove portion 122 . As described above, the width of the second rib portion 121 means the width of the second rib portion 121 in a cross section perpendicular to the extending direction of the second rib portion 121 . Therefore, the same effect as the relationship between the width of the first rib portion 111 and the width of the first groove portion 112 described above can be obtained. Specifically, when the second slow-cooling region 123 comes into contact with the material B during hot press-forming, the heat removal amount in the second groove portions 122 is less than the heat removal amount in the second rib portions 121 . Since the width of the second rib portion 121 is narrower than the width of the second groove portion 122, the amount of heat removal in the second rib portion 121 can be reduced. Therefore, in the second slow cooling region 123, the cooling rate of the material B can be made slower than in the second rapid cooling region 124, which will be described later. Therefore, when hot press forming is performed using the mold 10, the degree of quenching of the area of the material B that is in contact with the second slow cooling area 123 can be reduced. As a result, the material B (hot press-formed product) after hot press-forming can be formed with a shock absorbing region with reduced strength.
　［第２急冷領域１２４の構成］
　図７を参照して、下型１２の第２成形面１２０の第２急冷領域１２４では、第２リブ部１２１及び第２溝部１２２は形成されていない。つまり、第２成形面１２０の第２急冷領域１２４は、滑らかな面である。そのため、熱間プレス成形時において、第２急冷領域１２４の略全体が、素材Ｂと接触する。そのため、第２急冷領域１２４では、第２緩冷却領域１２３と比較して、素材Ｂの冷却速度を速くすることができる。そのため、金型１０を用いて熱間プレス成形が実施された場合、素材Ｂのうち、第２急冷領域１２４に接触した領域の焼入れの度合いを高めることができる。その結果、熱間プレス成形後の素材Ｂ（熱間プレス成形品）に、衝撃緩衝領域よりも強度の高い高強度領域を形成することができる。 [Configuration of the second rapid cooling region 124]
Referring to FIG. 7 , second rib portion 121 and second groove portion 122 are not formed in second rapid cooling region 124 of second molding surface 120 of lower die 12 . That is, the second quench region 124 of the second molding surface 120 is a smooth surface. Therefore, substantially the entire second quench region 124 is in contact with the material B during hot press forming. Therefore, in the second rapid cooling region 124 , the cooling rate of the material B can be made faster than in the second slow cooling region 123 . Therefore, when hot press forming is performed using the mold 10, the degree of quenching of the area of the material B that is in contact with the second rapid cooling area 124 can be increased. As a result, it is possible to form a high-strength region having a higher strength than the impact buffer region in the material B (hot press-formed product) after hot press-forming.
　［第１リブ部１１１及び第２リブ部１２１との関係］
　金型１０ではさらに、熱間プレス成形時において、第１成形面１１０の第１緩冷却領域１１３及び第２成形面１２０の第２緩冷却領域１２３を、第１緩冷却領域１１３の法線方向から見たとき、第１リブ部１１１と第２リブ部１２１とは、少なくとも一部が重複している。ここでいう、「熱間プレス成形時」とは、上型１１の成形面１１０の略全体と、下型１２の成形面１２０の略全体とが、素材Ｂと接触して素材Ｂに外力を付与している状態を意味し、金型１０が閉じた状態であって、上型１１が下死点で保持されつつ素材Ｂが金型１０により冷却されている状態を意味する。 [Relationship between first rib portion 111 and second rib portion 121]
Further, in the mold 10, during hot press molding, the first slow cooling region 113 of the first molding surface 110 and the second slow cooling region 123 of the second molding surface 120 are arranged in the normal direction of the first slow cooling region 113. When viewed from above, the first rib portion 111 and the second rib portion 121 at least partially overlap. Here, "at the time of hot press molding" means that substantially the entire molding surface 110 of the upper mold 11 and substantially the entire molding surface 120 of the lower mold 12 come into contact with the material B and apply an external force to the material B. It means a state in which the mold 10 is closed and the material B is cooled by the mold 10 while the upper mold 11 is held at the bottom dead center.
　この場合、図５Ａに示すとおり、熱間プレス成形時において、第１リブ部１１１が第２溝部１２２内に入り込んだりせず、第２リブ部１２１が第１溝部１１２内に入り込んだりしない。そのため、熱間プレス成形時に、第１リブ部１１１が第２溝部１２２内に入り込んだり、第２リブ部１２１が第１溝部１１２内に入り込んだりすることにより、素材Ｂが波状に変形するのを抑制できる。 In this case, as shown in FIG. 5A, the first rib portion 111 does not enter the second groove portion 122 and the second rib portion 121 does not enter the first groove portion 112 during hot press molding. Therefore, during hot press forming, the first rib portion 111 enters the second groove portion 122 or the second rib portion 121 enters the first groove portion 112, thereby preventing the material B from being deformed into a wavy shape. can be suppressed.
　［金型１０の特徴］
　以上のとおり、本実施形態の金型１０では、第１緩冷却領域１１３の第１リブ部１１１の幅は第１溝部１１２の幅よりも狭い。さらに、第２緩冷却領域１２３の第２リブ部１２１の幅は第２溝部１２２の幅よりも狭い。そのため、金型１０を用いて熱間プレス成形を実施した場合、第１緩冷却領域１１３及び第２緩冷却領域１２３で挟まれた素材Ｂの領域では、冷却速度が抑えられる。そのため、熱間プレス成形品内で、強度を抑えた衝撃緩衝領域と、衝撃緩衝領域よりも強度の高い高強度領域とを形成することができる。さらに、熱間プレス成形時に、第１緩冷却領域１１３及び第２緩冷却領域１２３を、第１緩冷却領域１１３の法線方向から見たとき、第１リブ部１１１と第２リブ部１２１とは、少なくとも一部が重複する。そのため、衝撃緩衝領域において、素材Ｂが波状に変形するのを抑制することができる。 [Features of mold 10]
As described above, in the mold 10 of the present embodiment, the width of the first rib portion 111 of the first slow cooling region 113 is narrower than the width of the first groove portion 112 . Furthermore, the width of the second rib portion 121 in the second slow cooling region 123 is narrower than the width of the second groove portion 122 . Therefore, when hot press molding is performed using the mold 10 , the cooling rate is suppressed in the area of the material B sandwiched between the first slow cooling area 113 and the second slow cooling area 123 . Therefore, in the hot press-formed product, it is possible to form a shock buffering region with reduced strength and a high-strength region with a higher strength than the shock buffering region. Furthermore, during hot press forming, when the first slow cooling region 113 and the second slow cooling region 123 are viewed from the normal direction of the first slow cooling region 113, the first rib portion 111 and the second rib portion 121 overlap at least partially. Therefore, it is possible to suppress the material B from deforming into a wavy shape in the impact buffering region.
　［金型１０の好ましい形態について］
　第１緩冷却領域１１３及び第２緩冷却領域１２３において、好ましくは、第１リブ部１１１と、第２リブ部１２１とは、同じ方向に延びている。さらに、第１溝部１１２と、第２溝部１２２とは、同じ方法に延びている。図５Ａ及び図６では、第１リブ部１１１と、第２リブ部１２１とは、Ｌ方向に延びており、第１溝部１１２と、第２溝部１２２とは、Ｌ方向に延びている。 [Regarding a preferred form of the mold 10]
In the first slow cooling region 113 and the second slow cooling region 123, the first rib portion 111 and the second rib portion 121 preferably extend in the same direction. Moreover, the first groove 112 and the second groove 122 extend in the same way. 5A and 6, the first rib portion 111 and the second rib portion 121 extend in the L direction, and the first groove portion 112 and the second groove portion 122 extend in the L direction.
　上述のとおり、第１リブ部１１１と、第１溝部１１２と、第２リブ部１２１と、第２溝部１２２とが、全て同じ方向に延在している場合、素材Ｂの熱伝達のシミュレーションでは、二次元でのシミュレーションを実施すれば足りる。つまり、第１リブ部１１１、第１溝部１１２、第２リブ部１２１及び、第２溝部１２２の延在方向に垂直な断面（つまり図５Ａに示す断面）での二次元のシミュレーションを実施すれば、その結果は、三次元のシミュレーションにより得られた結果と実質的に同じとなる。そのため、三次元のシミュレーションを実施する必要がない。そのため、素材Ｂの熱伝達について、より容易かつ正確なシミュレーションが可能となる。つまり、より容易かつ正確に冷却速度を制御することができる。この場合、素材Ｂの化学組成から、シミュレーションを用いることにより、所望のミクロ組織に制御することが可能になる。 As described above, when the first rib portion 111, the first groove portion 112, the second rib portion 121, and the second groove portion 122 all extend in the same direction, the heat transfer simulation of the material B is , it suffices to carry out a simulation in two dimensions. That is, if a two-dimensional simulation is performed on a cross section perpendicular to the extending direction of the first rib portion 111, the first groove portion 112, the second rib portion 121, and the second groove portion 122 (that is, the cross section shown in FIG. 5A), , the results are substantially the same as those obtained by three-dimensional simulations. Therefore, there is no need to perform a three-dimensional simulation. Therefore, the heat transfer of the material B can be easily and accurately simulated. That is, the cooling rate can be controlled more easily and accurately. In this case, it is possible to control the chemical composition of material B to a desired microstructure by using a simulation.
　例えば、素材Ｂが鋼材である場合、素材Ｂを熱間プレス成形した結果、熱間プレス成形品が硬質相だけでなく、残留オーステナイトを含有するミクロ組織となれば、熱間プレス成形品の衝撃吸収能がさらに高まる。ここで、硬質相とは、マルテンサイト及び／又はベイナイトからなる。 For example, when material B is steel, as a result of hot press molding of material B, if the hot press-formed product has a microstructure containing not only a hard phase but also retained austenite, the impact of the hot press-formed product Further increases the absorption capacity. Here, the hard phase consists of martensite and/or bainite.
　［好ましい第１リブ部１１１と第１溝部１１２との関係、及び、好ましい第２リブ部１２１及び第２溝部１２２との関係］
　好ましくは、緩冷却領域１１３に形成された第１リブ部１１１の幅は、第１溝部１１２の幅の１０～５０％であり、緩冷却領域１２３に形成された第２リブ部１２１の幅は、第２溝部１２２の幅の１０～５０％である。 [Relationship between preferred first rib portion 111 and first groove portion 112, and preferred relationship between second rib portion 121 and second groove portion 122]
Preferably, the width of the first rib portion 111 formed in the slow cooling region 113 is 10 to 50% of the width of the first groove portion 112, and the width of the second rib portion 121 formed in the slow cooling region 123 is , 10 to 50% of the width of the second groove portion 122 .
　第１リブ部１１１の幅が第１溝部１１２の幅の１０％以上であれば、第１リブ部１１１が素材Ｂを適切に抜熱する。この場合、素材Ｂの冷却速度が過剰に遅くなるのを抑制できる。そのため、素材Ｂのミクロ組織中にフェライト及びパーライトが生成するのを抑制でき、硬質相、又は、硬質相及び残留オーステナイトの生成が促進される。その結果、熱間プレス成形品の衝撃吸収能が向上する。 If the width of the first rib portion 111 is 10% or more of the width of the first groove portion 112, the first rib portion 111 removes heat from the material B appropriately. In this case, it is possible to prevent the cooling rate of the material B from becoming excessively slow. Therefore, the formation of ferrite and pearlite in the microstructure of material B can be suppressed, and the formation of hard phase or hard phase and retained austenite is promoted. As a result, the impact absorption capacity of the hot press-formed product is improved.
　一方、第１リブ部１１１の幅が第１溝部１１２の幅の５０％以下であれば、熱間プレス成形時において、冷却速度を遅くすることができる。冷却速度を遅くすることができれば、所望の素材温度で冷却を停止しやすくなる。例えば、Ｍｆ点～Ｍｓ点の間で冷却を停止して、マルテンサイト及び残留オーステナイトの生成量を調整してもよい。例えば、Ｍｓ点よりも高い温度で冷却を停止して、素材のミクロ組織をベイナイト主体の組織としてもよい。 On the other hand, if the width of the first rib portion 111 is 50% or less of the width of the first groove portion 112, the cooling rate can be slowed down during hot press molding. If the cooling rate can be slowed down, it becomes easier to stop cooling at a desired material temperature. For example, cooling may be stopped between the Mf point and the Ms point to adjust the amount of martensite and retained austenite produced. For example, the cooling may be stopped at a temperature higher than the Ms point, and the microstructure of the material may be made mainly of bainite.
　したがって、好ましくは、第１リブ部１１１の幅は、第１溝部１１２の幅の１０～５０％である。
　第１リブ部１１１の幅の第１溝部１１２の幅に対する比のさらに好ましい上限は４５％であり、さらに好ましくは４０％であり、さらに好ましくは３５％である。
　第１リブ部１１１の幅の第１溝部１１２の幅に対する比のさらに好ましい下限は１２％であり、さらに好ましくは１４％である。 Therefore, preferably, the width of the first rib portion 111 is 10-50% of the width of the first groove portion 112 .
More preferably, the upper limit of the ratio of the width of the first rib portion 111 to the width of the first groove portion 112 is 45%, more preferably 40%, and even more preferably 35%.
A more preferable lower limit of the ratio of the width of the first rib portion 111 to the width of the first groove portion 112 is 12%, more preferably 14%.
　図５Ｂは、熱間プレス成形時を示す図５Ａの素材Ｂを除いた模式図である。ここで、第１リブ部１１１の幅は次のとおり定義する。第１リブ部１１１の表面のうち、第２成形面１２０と対向する表面を、第１リブ部１１１の頂面と定義する。すなわち、第１リブ部１１１の表面のうち、熱間プレス成形時に素材Ｂと接触する表面を「頂面」と定義する。図５Ｂに示すとおり、第１リブ部１１１の延在方向に垂直な断面において、頂面１１１Ｐの幅Ｗ１１１Ｐを、第１リブ部１１１の幅と定義する。頂面１１１Ｐの幅Ｗ１１１Ｐはすなわち、第１リブ部１１１の延在方向及び頂面１１１Ｐの法線方向に垂直な方向（図５ＢではＷ方向）の頂面１１１Ｐの長さに相当する。 FIG. 5B is a schematic diagram of FIG. 5A excluding material B, showing the time of hot press molding. Here, the width of the first rib portion 111 is defined as follows. Of the surfaces of the first rib portion 111 , the surface facing the second molding surface 120 is defined as the top surface of the first rib portion 111 . That is, of the surfaces of the first rib portion 111, the surface that comes into contact with the material B during hot press molding is defined as the "top surface". As shown in FIG. 5B , the width W 111P of the top surface 111P in the cross section perpendicular to the extending direction of the first rib portion 111 is defined as the width of the first rib portion 111 . The width W 111P of the top surface 111P corresponds to the length of the top surface 111P in the direction (W direction in FIG. 5B) perpendicular to the extending direction of the first rib portion 111 and the normal direction of the top surface 111P.
　第１リブ部１１１の高さは次のとおり定義する。図５Ｂにおいて、第１リブ部１１１の頂面１１１Ｐから第１溝部１１２の溝底１１２Ｐまでの高さＨ１１１Ｐを、第１リブ部１１１の高さと定義する。換言すれば、第１リブ部１１１の頂面１１１Ｐから第１溝部１１２の溝底１１２Ｐまでの、頂面１１１Ｐの法線方向（図５ＢではＶ方向）の長さを、第１リブ部１１１の高さＨ１１１Ｐと定義する。 The height of the first rib portion 111 is defined as follows. 5B, the height H 111P from the top surface 111P of the first rib portion 111 to the groove bottom 112P of the first groove portion 112 is defined as the height of the first rib portion 111. As shown in FIG. In other words, the length from the top surface 111P of the first rib portion 111 to the groove bottom 112P of the first groove portion 112 in the normal direction (V direction in FIG. Define height H 111P .
　第１溝部１１２の幅は次のとおり定義する。図５Ｂに示すとおり、第１リブ部１１１の延在方向に垂直な断面において、隣り合う第１リブ部１１１同士の一方の頂面１１１Ｐの端点と、他方の頂面１１１Ｐの端点との間の隙間の幅Ｗ１１２Ｐを、第１溝部１１２の幅と定義する。 The width of the first groove portion 112 is defined as follows. As shown in FIG. 5B, in a cross section perpendicular to the extending direction of the first rib portion 111, the distance between the endpoint of one top surface 111P of the adjacent first rib portions 111 and the endpoint of the other top surface 111P of the adjacent first rib portions 111 The width W 112P of the gap is defined as the width of the first groove portion 112 .
　第２リブ部１２１の幅は次のとおり定義する。第２リブ部１２１の表面のうち、第１成形面１１０と対向する表面を、第２リブ部１２１の頂面と定義する。すなわち、第２リブ部１２１の表面のうち、熱間プレス成形時に素材Ｂと接触する表面を「頂面」と定義する。図５Ｂに示すとおり、第２リブ部１２１の延在方向に垂直な断面において、頂面１２１Ｐの幅Ｗ１２１Ｐを、第２リブ部１２１の幅と定義する。頂面１２１Ｐの幅Ｗ１２１Ｐはすなわち、第２リブ部１２１の延在方向及び頂面１２１Ｐの法線方向に垂直な方向（図５ＢではＷ方向）の頂面１２１Ｐの長さに相当する。 The width of the second rib portion 121 is defined as follows. Of the surfaces of the second rib portion 121 , the surface facing the first molding surface 110 is defined as the top surface of the second rib portion 121 . That is, of the surfaces of the second rib portion 121, the surface that comes into contact with the material B during hot press molding is defined as the "top surface". As shown in FIG. 5B, the width W121P of the top surface 121P in the cross section perpendicular to the extending direction of the second rib portion 121 is defined as the width of the second rib portion 121. As shown in FIG. The width W121P of the top surface 121P corresponds to the length of the top surface 121P in the direction perpendicular to the extending direction of the second rib portion 121 and the normal direction of the top surface 121P (W direction in FIG. 5B).
　第２リブ部１２１の高さは次のとおり定義する。図５Ｂにおいて、第２リブ部１２１の頂面１２１Ｐから第２溝部１２２の溝底１２２Ｐまでの高さＨ１２１Ｐを、第２リブ部１２１の高さと定義する。換言すれば、第２リブ部１２１の頂面１２１Ｐから第２溝部１２２の溝底１２２Ｐまでの、頂面１２１Ｐの法線方向（図５ＢではＶ方向）の長さを、第２リブ部１２１の高さと定義する。 The height of the second rib portion 121 is defined as follows. 5B, the height H121P from the top surface 121P of the second rib portion 121 to the groove bottom 122P of the second groove portion 122 is defined as the height of the second rib portion 121. As shown in FIG. In other words, the length from the top surface 121P of the second rib portion 121 to the groove bottom 122P of the second groove portion 122 in the normal direction of the top surface 121P (in FIG. Define height.
　第２溝部１２２の幅は次のとおり定義する。図５Ｂに示すとおり、第２リブ部１２１の延在方向に垂直な断面において、隣り合う第２リブ部１２１同士の一方の頂面１２１Ｐの端点と、他方の頂面１２１Ｐの端点との間の隙間の幅Ｗ１２２Ｐを、第２溝部１２２の幅と定義する。 The width of the second groove portion 122 is defined as follows. As shown in FIG. 5B, in a cross section perpendicular to the extending direction of the second rib portion 121, the distance between the end point of one top surface 121P of the adjacent second rib portions 121 and the end point of the other top surface 121P The width W 122P of the gap is defined as the width of the second groove portion 122 .
　なお、第１リブ部１１１又は第２リブ部１２１の、延在方向に垂直な断面での形状は、図５Ａ及び図５Ｂに示すように矩形状であってもよいし、図５Ｃに示すように、頂面１１１Ｐ又は１２１Ｐに向かって幅が狭まる台形状であってもよい。また、第１リブ部１１１又は第２リブ部１２１では、図５Ｄに示すように、頂面１１１Ｐ又は１２１Ｐの角が面取りされていたり、第１リブ部１１１又は第２リブ部１２１の根元が面取りされていたりしてもよい。また、頂面１１１Ｐ又は１２１Ｐの角が丸みを帯びていたり（つまり、フィレット加工されていたり）、第１リブ部１１１又は第２リブ部１２１の根元が丸みを帯びていたり（つまり、フィレット加工されていたり）してもよい。 The shape of the first rib portion 111 or the second rib portion 121 in a cross section perpendicular to the extending direction may be rectangular as shown in FIGS. 5A and 5B, or may be rectangular as shown in FIG. Alternatively, it may be trapezoidal in shape, the width of which narrows toward the top surface 111P or 121P. In the first rib portion 111 or the second rib portion 121, as shown in FIG. 5D, the corners of the top surface 111P or 121P are chamfered, or the base of the first rib portion 111 or the second rib portion 121 is chamfered. It may have been. In addition, the corners of the top surface 111P or 121P may be rounded (that is, filleted), or the base of the first rib portion 111 or the second rib portion 121 may be rounded (that is, filledeted). can be used).
　なお、頂面（１１１Ｐ又は１２１Ｐ）が面取り又はフィレット加工されている場合、頂面（１１１Ｐ又は１２１Ｐ）の幅は、頂面（１１１Ｐ及び１２１Ｐ）のうち、面取り及びフィレット加工されていない部分の幅とする。 When the top surface (111P or 121P) is chamfered or filleted, the width of the top surface (111P or 121P) is the width of the portion of the top surface (111P and 121P) that is not chamfered or filleted. and
　上述のとおり、本実施形態の金型１０は、熱間プレス成形用の金型である。熱間プレス成形時、素材Ｂの温度はＡｃ３点以上であり、温間プレス成形よりも高い。そのため、熱間プレス成形時の素材Ｂは、温間プレス成形時の素材と比較して、硬さが低く、加工性に優れる。そのため、熱間プレス成形時に素材Ｂに掛かる面圧は、温間プレス成形時よりも低い。そのため、第１リブ部１１１の幅が、第１溝部１１２の幅の５０％以下であっても、素材Ｂの表面には疵がつきにくい。 As described above, the mold 10 of this embodiment is a mold for hot press molding. During hot press molding, the temperature of material B is A c 3 point or higher, which is higher than warm press molding. Therefore, the material B for hot press molding has a lower hardness and excellent workability than the material for warm press molding. Therefore, the surface pressure applied to the material B during hot press-forming is lower than that during warm press-forming. Therefore, even if the width of the first rib portion 111 is 50% or less of the width of the first groove portion 112, the surface of the material B is less likely to be scratched.
　第１リブ部１１１及び第１溝部１１２との関係と同様に、第２リブ部１２１の幅が第２溝部１２２の幅の１０％以上であれば、素材Ｂの冷却速度の過剰な低減を抑制できる。そのため、熱間プレス成形品の衝撃吸収能が向上する。 Similar to the relationship between the first rib portion 111 and the first groove portion 112, if the width of the second rib portion 121 is 10% or more of the width of the second groove portion 122, excessive reduction in the cooling rate of the material B is suppressed. can. Therefore, the impact absorption capacity of the hot press-formed product is improved.
　一方、第２リブ部１２１の幅が第２溝部１２２の幅の５０％以下であれば、素材Ｂの冷却速度を適度に遅くすることができる。そのため、熱間プレス成形時において、冷却停止温度（つまり、素材Ｂから金型１０を離すときの素材Ｂの温度）を調整しやすくなる。例えば、冷却停止温度をＭｓ点よりも上の温度に調整したり、冷却停止温度を、Ｍｆ点～Ｍｓ点の間に調整したり、又は、Ｍｓ点超～５００℃の間に調整したりしやすくなる。 On the other hand, if the width of the second rib portion 121 is 50% or less of the width of the second groove portion 122, the cooling rate of the material B can be moderately slowed down. Therefore, it becomes easier to adjust the cooling stop temperature (that is, the temperature of the material B when the mold 10 is separated from the material B) during hot press molding. For example, the cooling stop temperature is adjusted to a temperature above the Ms point, the cooling stop temperature is adjusted between the Mf point and the Ms point, or the Ms point is adjusted to 500 ° C. easier.
　したがって、第２リブ部１２１の幅は、第２溝部１２２の幅の１０～５０％である。
　第２リブ部１２１の幅の第２溝部１２２の幅に対する比の好ましい上限は４５％であり、さらに好ましくは４０％であり、さらに好ましくは３５％である。
　第２リブ部１２１の幅の第２溝部１２２の幅に対する比のさらに好ましい下限は１２％であり、さらに好ましくは１４％である。 Therefore, the width of the second rib portion 121 is 10 to 50% of the width of the second groove portion 122 .
A preferable upper limit of the ratio of the width of the second rib portion 121 to the width of the second groove portion 122 is 45%, more preferably 40%, and still more preferably 35%.
A more preferable lower limit of the ratio of the width of the second rib portion 121 to the width of the second groove portion 122 is 12%, more preferably 14%.
　上述の第１リブ部１１１の幅及び第１溝部１１２の幅の関係と同様に、第２リブ部１２１の幅が第２溝部１２２の幅の５０％以下であっても、素材Ｂの表面には疵がつきにくい。 Similar to the relationship between the width of the first rib portion 111 and the width of the first groove portion 112 described above, even if the width of the second rib portion 121 is 50% or less of the width of the second groove portion 122, the surface of the material B is scratch resistant.
　［第１リブ部１１１の好ましい幅及び好ましい高さ、第２リブ部１２１の好ましい幅及び好ましい高さ］
　好ましくは、第１緩冷却領域１１３の少なくとも一部において、第１リブ部１１１の幅は１．０～８．０ｍｍであり、第１リブ部１１１の高さは０．２～５．０ｍｍであり、第２緩冷却領域１２３の少なくとも一部において、第２リブ部１２１の幅は１．０～８．０ｍｍであり、第２リブ部１２１の高さは０．２～５．０ｍｍである。第１リブ部１１１の高さは、第１溝部１１２の深さに相当する。同様に、第２リブ部１２１の高さは、第２溝部１２２の深さに相当する。 [Preferred Width and Height of First Rib Portion 111, Preferred Width and Height of Second Rib Portion 121]
Preferably, in at least part of the first slow cooling region 113, the width of the first rib portion 111 is 1.0 to 8.0 mm, and the height of the first rib portion 111 is 0.2 to 5.0 mm. In at least part of the second slow cooling region 123, the width of the second rib portion 121 is 1.0 to 8.0 mm, and the height of the second rib portion 121 is 0.2 to 5.0 mm. . The height of the first rib portion 111 corresponds to the depth of the first groove portion 112 . Similarly, the height of the second rib portion 121 corresponds to the depth of the second groove portion 122 .
　第１リブ部１１１の幅又は第２リブ部１２１の幅を８．０ｍｍ以下にすれば、素材Ｂにおける第１リブ部１１１の幅方向又は第２リブ部１２１の幅方向の温度ばらつきを低減することができる。そのため、熱間プレス成形時において、素材Ｂの温度ばらつきに由来する、冷却速度のばらつきを低減できる。 If the width of the first rib portion 111 or the width of the second rib portion 121 is 8.0 mm or less, the temperature variation in the width direction of the first rib portion 111 or the width direction of the second rib portion 121 in the material B is reduced. be able to. Therefore, it is possible to reduce variations in the cooling rate caused by variations in the temperature of the material B during hot press molding.
　一方、第１リブ部１１１の幅又は第２リブ部１２１の幅を１．０ｍｍ以上にすれば、熱間プレス成形を実施する際に、第１リブ部１１１又は第２リブ部１２１が折れにくくなり、生産性が高まる。したがって、第１リブ部１１１の好ましい幅は、１．０～８．０ｍｍである。第２リブ部１２１の好ましい幅は、１．０～８．０ｍｍである。 On the other hand, if the width of the first rib portion 111 or the width of the second rib portion 121 is set to 1.0 mm or more, the first rib portion 111 or the second rib portion 121 is less likely to break during hot press molding. and increase productivity. Therefore, the preferred width of the first rib portion 111 is 1.0 to 8.0 mm. A preferable width of the second rib portion 121 is 1.0 to 8.0 mm.
　第１リブ部１１１の幅のさらに好ましい下限は１．８ｍｍであり、さらに好ましくは２．０ｍｍである。第２リブ部１２１の幅のさらに好ましい下限は１．８ｍｍであり、さらに好ましくは２．０ｍｍである。この場合、第１リブ部１１１及び第２リブ部１２１はさらに折れにくくなる。また、第１リブ部１１１及び第２リブ部１２１の寸法精度が緩和されるため、加工しやすくなる。 A more preferable lower limit of the width of the first rib portion 111 is 1.8 mm, more preferably 2.0 mm. A more preferable lower limit of the width of the second rib portion 121 is 1.8 mm, more preferably 2.0 mm. In this case, the first rib portion 111 and the second rib portion 121 are even less likely to break. In addition, since the dimensional accuracy of the first rib portion 111 and the second rib portion 121 is relaxed, processing becomes easier.
　第１リブ部１１１の高さ又は第２リブ部１２１の高さを０．２ｍｍ以上にすれば、第１溝部１１２又は第２溝部１２２における、素材Ｂからの抜熱の発生を抑制できる。一方、第１リブ部１１１の高さ又は第２リブ部１２１の高さを５．０ｍｍ以下にすれば、熱間プレス成形を実施する際に、第１リブ部１１１又は第２リブ部１２１が折れにくくなり、生産性が高まる。したがって、第１リブ部１１１の好ましい高さは０．２～５．０ｍｍである。第２リブ部１２２の好ましい高さは０．２～５．０ｍｍである。 If the height of the first rib portion 111 or the height of the second rib portion 121 is set to 0.2 mm or more, the occurrence of heat removal from the material B in the first groove portion 112 or the second groove portion 122 can be suppressed. On the other hand, if the height of the first rib portion 111 or the height of the second rib portion 121 is set to 5.0 mm or less, the first rib portion 111 or the second rib portion 121 is Less likely to break, higher productivity. Therefore, the preferred height of the first rib portion 111 is 0.2 to 5.0 mm. A preferred height of the second rib portion 122 is 0.2 to 5.0 mm.
　なお、第１緩冷却領域１１３及び第２緩冷却領域１２３のうち、少なくとも一部の領域において、第１リブ部１１１又は第２リブ部１２１の、幅又は高さを上記のとおりに調整すれば、上記少なくとも一部の領域では、上記好ましい効果を得ることができる。したがって、本実施形態では、第１緩冷却領域１１３及び第２緩冷却領域１２３の少なくとも一部において、第１リブ部１１１又は第２リブ部１２１の幅又は高さを、上記のとおり調整すればよい。好ましくは、第１緩冷却領域１１３の全体にわたって、第１リブ部１１１の幅が１．０～８．０ｍｍであり、高さが０．２～５．０ｍｍであり、第２緩冷却領域１２３の全体にわたって、第２リブ部１２１の幅が１．０～８．０ｍｍであり、高さが０．２～５．０ｍｍである。 If the width or height of the first rib portion 111 or the second rib portion 121 is adjusted as described above in at least a part of the first slow cooling region 113 and the second slow cooling region 123, , the above-mentioned preferable effect can be obtained in the above-mentioned at least part of the region. Therefore, in the present embodiment, if the width or height of the first rib portion 111 or the second rib portion 121 is adjusted as described above in at least a part of the first slow cooling region 113 and the second slow cooling region 123, good. Preferably, the width of the first rib portion 111 is 1.0 to 8.0 mm and the height is 0.2 to 5.0 mm over the entire first slow cooling region 113, and the second slow cooling region 123 , the width of the second rib portion 121 is 1.0 to 8.0 mm and the height is 0.2 to 5.0 mm.
　さらに好ましくは、第１緩冷却領域１１３の少なくとも一部の領域において、第１リブ部１１１の幅は１．０～４．０ｍｍであり、かつ、第１溝部１１２の幅の１０～３０％であり、さらに、第２緩冷却領域１２３の少なくとも一部の領域において、第２リブ部１２１の幅は１．０～４．０ｍｍであり、かつ、第２溝部１２２の幅の１０～３０％である。この場合、素材Ｂの冷却速度をさらに遅くすることができる。そのため、冷却停止温度を所望の温度により調整しやすい。さらに、熱間プレス成形時の素材Ｂの温度ばらつきを低減できる。 More preferably, in at least a partial region of the first slow cooling region 113, the width of the first rib portion 111 is 1.0 to 4.0 mm and 10 to 30% of the width of the first groove portion 112. Further, in at least a partial region of the second slow cooling region 123, the width of the second rib portion 121 is 1.0 to 4.0 mm and 10 to 30% of the width of the second groove portion 122. be. In this case, the cooling rate of material B can be further reduced. Therefore, it is easy to adjust the cooling stop temperature to a desired temperature. Furthermore, the temperature variation of the material B during hot press molding can be reduced.
　［Ｆｎ１について］
　金型１０において、第１リブ部１１１と第２リブ部１２１とが同じ方向に延びており、第１溝部１１２と第２溝部１２２とが同じ方向に延びており、第１リブ部１１１の幅は、第１溝部１１２の幅の１０～５０％であり、第２リブ部１２１の幅は、第２溝部１２２の幅の１０～５０％であり、第１リブ部１１１及び第２リブ部１２１の幅が１．０～８．０ｍｍであり、第１リブ部１１１及び第２リブ部１２１の高さが０．２～５．０ｍｍである場合を想定する。
　この場合、好ましくは、式（１）で定義されるＦｎ１が１４以下である。
　Ｆｎ１＝Ｗｒ０．９／Ｐ００．８＋０．０５Ｈｒ　（１）
　ここで、Ｗｒは第１リブ部１１１及び第２リブ部１２１の幅（ｍｍ）である。Ｐ０＝Ｗｒ／Ｗｓであり、Ｗｓは第１溝部１１２及び第２溝部１２２の幅（ｍｍ）である。Ｈｒは第１リブ部１１１及び第２リブ部１２１の高さ（ｍｍ）である。以下、Ｆｎ１について説明する。 [About Fn1]
In the mold 10, the first rib portion 111 and the second rib portion 121 extend in the same direction, the first groove portion 112 and the second groove portion 122 extend in the same direction, and the width of the first rib portion 111 is 10 to 50% of the width of the first groove portion 112, the width of the second rib portion 121 is 10 to 50% of the width of the second groove portion 122, and the first rib portion 111 and the second rib portion 121 is 1.0 to 8.0 mm, and the height of the first rib portion 111 and the second rib portion 121 is 0.2 to 5.0 mm.
In this case, Fn1 defined by formula (1) is preferably 14 or less.
Fn1= Wr0.9 / P00.8 +0.05Hr (1)
Here, Wr is the width (mm) of the first rib portion 111 and the second rib portion 121 . P0=Wr/Ws, where Ws is the width (mm) of the first groove 112 and the second groove 122 . Hr is the height (mm) of the first rib portion 111 and the second rib portion 121 . Fn1 will be described below.
　図８はＦｎ１と、第１緩冷却領域１１３及び第２緩冷却領域１２３での温度ばらつきΔＴ（℃）との関係を示す図である。図８は、次に示す２次元の熱伝達シミュレーションにより得られた結果である。具体的には、図９に示す熱伝導モデルを想定した差分法により、熱間プレス成形時における素材Ｂの温度分布及び当該温度分布の経時変化をシミュレートした。 FIG. 8 is a diagram showing the relationship between Fn1 and the temperature variation ΔT (°C) in the first slow cooling region 113 and the second slow cooling region 123. FIG. FIG. 8 shows results obtained by the following two-dimensional heat transfer simulation. Specifically, the temperature distribution of the material B during hot press molding and the change over time of the temperature distribution were simulated by the finite difference method assuming the heat conduction model shown in FIG.
　図９は、第１緩冷却領域１１３及び第２緩冷却領域１２３における、第１リブ部１１１及び第２リブ部１２１の幅方向の断面図である。素材Ｂを要素幅Ｄ０＝１ｍｍ、厚さＤ１＝素材Ｂの板厚（１．４ｍｍで想定）、Ｌ方向に単位長さを有する複数の要素Ｅに区画した。ｉ番目（ｉは自然数）の要素Ｅでの熱伝導及び熱伝達による単位時間（１秒）当たりの熱量の収支Ｑ（Ｗ／ｍ２）は以下の式で示される。 FIG. 9 is a widthwise cross-sectional view of the first rib portion 111 and the second rib portion 121 in the first slow cooling region 113 and the second slow cooling region 123 . The material B was divided into a plurality of elements E each having an element width D0 of 1 mm, a thickness D1 of the material B (assumed to be 1.4 mm), and a unit length in the L direction. The balance Q (W/m 2 ) of the amount of heat per unit time (1 second) due to heat conduction and heat transfer in the i-th (i is a natural number) element E is shown by the following formula.
　Ｑ＝（Ｑ２ｉ）―（Ｑ２ｉ＋１）－２Ｑ１
　この式の各項を、次の式で定義した。
　（要素Ｅが第１リブ部１１１及び第２リブ部１２１に接触している場合）
　Ｑ１：素材Ｂとリブ部（１１１又は１２１）との接触熱伝達による要素Ｅの単位時間当たりの金型への熱量の移動（Ｗ／ｍ２）
　Ｑ１＝－ｈ（Ｔｒ－Ｔｂｉ）
　熱伝達係数ｈ＝２０００Ｗ／ｍ２・Ｋ
　金型温度Ｔｒ＝１００℃
　Ｔｂｉ：素材Ｂにおけるｉ番目の要素Ｅの温度
　（要素Ｅが第１リブ部１１１及び第２リブ部１２１に接触していない場合）
　Ｑ１：溝部（１１２又は１２２）での空気を介した熱伝導による要素Ｅの単位時間当たりの熱量の金型への移動（Ｗ／ｍ２）
　Ｑ１＝－λａ（Ｔｒ－Ｔｂｉ）／Ｈｒ
　λａ：空気の熱伝導率＝０．０４Ｗ／ｍ・Ｋ
　Ｑ２ｉ：素材Ｂ内の熱伝導によるｉ－１番目の要素Ｅから単位時間当たりの隣接するｉ番目の要素Ｅへの熱量の移動（Ｗ／ｍ２）
　Ｑ２ｉ＝－λｂ（Ｔｂｉ－Ｔｂｉ－１）／Δｘ
　λｂ：素材Ｂの熱伝導率＝５０Ｗ／ｍ・Ｋ
　Ｔｂｉ：ｉ番目の要素Ｅ（素材Ｂ）の温度
　Ｔｂｉ－１：ｉ番目の要素Ｅと隣接するｉ－１番目の要素Ｅの温度
　Δｘ：隣接する要素Ｅ間の距離＝１ｍｍ Q=(Q2i)-(Q2i+1)-2Q1
Each term of this formula is defined by the following formula.
(When the element E is in contact with the first rib portion 111 and the second rib portion 121)
Q1: Transfer of heat quantity to the mold per unit time of element E due to contact heat transfer between material B and rib (111 or 121) (W/m 2 )
Q1=-h(Tr-Tbi)
Heat transfer coefficient h = 2000 W/m 2 K
Mold temperature Tr = 100°C
Tbi: Temperature of i-th element E in material B (when element E is not in contact with first rib portion 111 and second rib portion 121)
Q1: Transfer of the amount of heat per unit time from the element E to the mold due to heat conduction through the air in the groove (112 or 122) (W/m 2 )
Q1=-λa(Tr-Tbi)/Hr
λa: Thermal conductivity of air = 0.04 W/m K
Q2i: heat transfer from the i−1th element E to the adjacent ith element E per unit time due to heat conduction in the material B (W/m 2 )
Q2i=-λb(Tbi-Tbi-1)/Δx
λb: Thermal conductivity of material B = 50 W/m K
Tbi: temperature of i-th element E (material B) Tbi-1: temperature of i-1-th element E adjacent to i-th element E Δx: distance between adjacent elements E = 1 mm
　ところで、熱収支Ｑに伴う単位時間あたりの要素Ｅの温度変化ΔＴｂ（℃）は次の式で示される。
　ΔＴｂ＝Ｑ／（ｃ・ρ・Ｄ０・Ｄ１）
　ｃ：素材Ｂの比熱＝０．４３５Ｊ／（ｇ・Ｋ）
　ρ：素材Ｂの密度＝７．８×１０＾３（ｇ／ｍ３） By the way, the temperature change ΔTb (°C) of the element E per unit time associated with the heat balance Q is expressed by the following formula.
ΔTb=Q/(c・ρ・D0・D1)
c: Specific heat of material B = 0.435 J/(g K)
ρ: Density of material B = 7.8 × 10^3 (g/m 3 )
　上述の熱伝導モデルにおいて、第１リブ部１１１と第２リブ部１２１とが同じ方向に延びており、第１溝部１１２及び第２溝部１２２が同じ方向に延びているとした。さらに、第１リブ部１１１の幅が第２リブ部１２１の幅と同じであり、第１リブ部１１１の高さが第２リブ部１２１の高さと同じであるとした。さらに、第１溝部１１２の幅が第２溝部１２２の幅と同じであるとした。さらに、図９に示すとおり、熱間プレス成形時において、第１リブ部１１１の頂面全体が、第２リブ部１２１の頂面全体と重なるとした。なお、リブ部（１１１及び１２１）の延在方向に垂直な断面形状は矩形状であった。 In the heat conduction model described above, it is assumed that the first rib portion 111 and the second rib portion 121 extend in the same direction, and the first groove portion 112 and the second groove portion 122 extend in the same direction. Further, the width of the first rib portion 111 is the same as the width of the second rib portion 121 and the height of the first rib portion 111 is the same as the height of the second rib portion 121 . Furthermore, it is assumed that the width of the first groove portion 112 is the same as the width of the second groove portion 122 . Furthermore, as shown in FIG. 9, the entire top surface of the first rib portion 111 overlaps the entire top surface of the second rib portion 121 during hot press molding. The cross-sectional shape perpendicular to the extending direction of the rib portions (111 and 121) was rectangular.
　初期条件として時刻０（秒）における要素Ｅの温度Ｔｂｉを６２２℃とした。さらに、図９の右方と左方にそれぞれ５００～１０００ｍｍの区間では要素Ｅが第１リブ部１１１および第２リブ部１２１に接触しているとし（つまり、上記区間を緩冷却領域１１３及び１２３とし）、境界条件として図９の右方と左方それぞれ１０００ｍｍ地点での要素Ｅにおける素材Ｂ内の熱伝導は断熱するとした。そして、時間間隔０．０１秒ごとに要素Ｅの温度変化ΔＴｂを算出する逐次計算を行うことで、素材Ｂの温度分布及びその経時変化をシミュレートした。 As an initial condition, the temperature Tbi of element E at time 0 (second) was set to 622°C. Furthermore, it is assumed that the element E is in contact with the first rib portion 111 and the second rib portion 121 in sections of 500 to 1000 mm on the right and left sides of FIG. ), and as a boundary condition, the heat conduction in the material B in the element E at the points of 1000 mm on the right and left sides of FIG. 9 is assumed to be adiabatic. Then, the temperature distribution of the material B and its change over time were simulated by performing sequential calculations for calculating the temperature change ΔTb of the element E at intervals of 0.01 second.
　リブ部（１１１及び１２１）の幅、高さ、溝部（１１２及び１２２）の幅を変化させて、図９の右方と左方にそれぞれ２５０ｍｍ以内の区間におけるＴｂｉの最大値Ｔｂｉｍａｘと最小値Ｔｂｉｍｉｎの差Ｔｂｉｍａｘ－Ｔｂｉｍｉｎを素材Ｂでの温度ばらつきΔＴ（℃）と定義して求めた。求めたΔＴを用いて、図８を作成した。 By changing the width and height of the ribs (111 and 121) and the width of the grooves (112 and 122), the maximum value Tbimax and the minimum value Tbimin of Tbi in sections within 250 mm to the right and left of FIG. The difference Tbimax−Tbimin was defined as the temperature variation ΔT (° C.) of the material B and obtained. FIG. 8 was created using the obtained ΔT.
　図８を参照して、Ｆｎ１が１４よりも高い場合、Ｆｎ１の低下とともに、ΔＴは急速に低下する。そして、Ｆｎ１が１４以下となったとき、Ｆｎ１の低下に伴うΔＴの低下度合いが緩やかになる。Ｆｎ１が１０以下となったときさらに、Ｆｎ１の低下に伴うΔＴの低下度合いが緩やかになる。したがって、図８のグラフでは、Ｆｎ１＝１４近傍と、Ｆｎ１＝１０近傍で変曲点が存在する。 Referring to FIG. 8, when Fn1 is higher than 14, ΔT rapidly decreases as Fn1 decreases. Then, when Fn1 becomes 14 or less, the degree of decrease in ΔT accompanying the decrease in Fn1 becomes moderate. When Fn1 becomes 10 or less, the degree of decrease in ΔT accompanying the decrease in Fn1 becomes gentler. Therefore, in the graph of FIG. 8, there are inflection points near Fn1=14 and Fn1=10.
　したがって、Ｆｎ１の好ましい上限は１４であり、さらに好ましくは１０である。Ｆｎ１が１４以下であれば、例えば、素材Ｂの温度ばらつきΔＴは１１０℃以下となる。また、Ｆｎ１が１０以下であれば、例えば、素材Ｂの温度ばらつきΔＴは４０℃以下になる。 Therefore, the preferred upper limit of Fn1 is 14, more preferably 10. If Fn1 is 14 or less, for example, the temperature variation ΔT of material B is 110° C. or less. Also, if Fn1 is 10 or less, for example, the temperature variation ΔT of the material B is 40° C. or less.
　［Ｆｎ２について］
　金型１０において、第１リブ部１１１と第２リブ部１２１とが同じ方向に延びており、第１溝部１１２と第２溝部１２２とが同じ方向に延びており、第１リブ部１１１の幅は、第１溝部１１２の幅の１０～５０％であり、第２リブ部１２１の幅は、第２溝部１２２の幅の１０～５０％であり第１リブ部１１１及び第２リブ部１２１の幅が１．０～８．０ｍｍであり、第１リブ部１１１及び第２リブ部１２１の高さが０．２～５．０ｍｍである場合を想定する。
　この場合、好ましくは、式（２）で定義されるＦｎ２が３０以上である。
　Ｆｎ２＝Ｗｓ２×Ｈｒ０．４／Ｗｒ　（２）
　ここで、Ｗｓは第１溝部１１２及び第２溝部１２２の幅（ｍｍ）である。Ｗｒは第１リブ部１１１及び第２リブ部１２１の幅（ｍｍ）である。Ｈｒは第１リブ部１１１及び第２リブ部１２１の高さ（ｍｍ）である。 [About Fn2]
In the mold 10, the first rib portion 111 and the second rib portion 121 extend in the same direction, the first groove portion 112 and the second groove portion 122 extend in the same direction, and the width of the first rib portion 111 is 10 to 50% of the width of the first groove portion 112, the width of the second rib portion 121 is 10 to 50% of the width of the second groove portion 122, and the width of the first rib portion 111 and the second rib portion 121 is Assume that the width is 1.0 to 8.0 mm and the height of the first rib portion 111 and the second rib portion 121 is 0.2 to 5.0 mm.
In this case, Fn2 defined by formula (2) is preferably 30 or more.
Fn2=Ws2* Hr0.4 /Wr ( 2 )
Here, Ws is the width (mm) of the first groove portion 112 and the second groove portion 122 . Wr is the width (mm) of the first rib portion 111 and the second rib portion 121 . Hr is the height (mm) of the first rib portion 111 and the second rib portion 121 .
　図１０はＦｎ２と、熱間プレス成形時の素材Ｂの冷却速度Ｖ（℃／秒）との関係を示す図である。図１０は図９に示す熱伝導モデルを用いた上述の２次元の熱伝達シミュレーションにより得られた。なお、熱伝達シミュレーションにおいて、冷却速度Ｖは、時刻０から要素Ｅの温度が４００℃になる時刻までの、要素Ｅの単位時間ごとの温度変化を時間平均することで求めた。ここで冷却速度の算出に用いる要素Ｅはその温度ＴｂｉがＴｂｉｍａｘを示す要素とした。 FIG. 10 is a diagram showing the relationship between Fn2 and the cooling rate V (°C/sec) of material B during hot press molding. FIG. 10 was obtained by the above two-dimensional heat transfer simulation using the heat transfer model shown in FIG. In the heat transfer simulation, the cooling rate V was obtained by averaging temperature changes of the element E per unit time from time 0 to the time when the temperature of the element E reached 400°C. Here, the element E used for calculating the cooling rate is an element whose temperature Tbi indicates Tbimax.
　図１０を参照して、Ｆｎ２が増加するに従い、素材Ｂの冷却速度Ｖは急速に低下し、その後、冷却速度Ｖの低下度合いは緩やかになる。したがって、Ｆｎ２の好ましい下限は３０であり、さらに好ましくは４５であり、さらに好ましくは９０である。Ｆｎ２が３０以上であれば、例えば、素材Ｂの冷却速度Ｖは８０℃／秒以下になる。そのため、熱間プレス成形時において、冷却停止温度（つまり、素材Ｂから金型１０を離すときの素材Ｂの温度）を所望の温度に調整しやすくなる。Ｆｎ２が４５以上であれば、例えば、素材Ｂの冷却速度は７０℃／秒以下になる。そのため、冷却停止温度を所望の温度にさらに調整しやすくなる。Ｆｎ２が９０以上であれば、例えば、素材Ｂの冷却速度Ｖは５０℃／秒以下となる。そのため、冷却停止温度を所望の温度にさらに調整しやすくなる。 Referring to FIG. 10, as Fn2 increases, the cooling rate V of material B rapidly decreases, and thereafter the rate of decrease in cooling rate V becomes moderate. Therefore, the preferred lower limit for Fn2 is 30, more preferably 45, and even more preferably 90. If Fn2 is 30 or more, for example, the cooling rate V of material B is 80° C./second or less. Therefore, during hot press molding, it becomes easier to adjust the cooling stop temperature (that is, the temperature of the material B when the mold 10 is separated from the material B) to a desired temperature. If Fn2 is 45 or more, for example, the cooling rate of material B is 70° C./second or less. Therefore, it becomes easier to adjust the cooling stop temperature to a desired temperature. If Fn2 is 90 or more, for example, the cooling rate V of material B is 50° C./second or less. Therefore, it becomes easier to adjust the cooling stop temperature to a desired temperature.
　金型１０において、さらに好ましくは、Ｆｎ１が１４以下であり、かつ、Ｆｎ２が３０以上である。この場合、素材Ｂの温度ばらつきΔＴをより抑制でき、かつ、冷却停止温度を所望の温度により調整しやすくなる。 In the mold 10, Fn1 is more preferably 14 or less and Fn2 is 30 or more. In this case, the temperature variation ΔT of the material B can be further suppressed, and the cooling stop temperature can be easily adjusted to a desired temperature.
　さらに好ましくは、金型１０において、第１リブ部１１１と第２リブ部１２１とが同じ方向に延びており、第１溝部１１２と第２溝部１２２とが同じ方向に延びており、第１リブ部１１１の幅は１．０～４．０ｍｍであり、かつ、第１溝部１１２の幅の１０～３０％であり、さらに、第２リブ部１２１の幅は１．０～４．０ｍｍであり、かつ、第２溝部１２２の幅の１０～３０％であり、Ｆｎ１が１４以下、及び／又は、Ｆｎ２が３０以上である。この場合、素材Ｂの冷却速度をさらに遅くすることができる。そのため、冷却停止温度を所望の温度により調整しやすい。さらに、熱間プレス成形時の素材Ｂの温度ばらつきを低減できる。 More preferably, in the mold 10, the first rib portion 111 and the second rib portion 121 extend in the same direction, the first groove portion 112 and the second groove portion 122 extend in the same direction, and the first rib The width of the portion 111 is 1.0 to 4.0 mm and 10 to 30% of the width of the first groove portion 112, and the width of the second rib portion 121 is 1.0 to 4.0 mm. and 10 to 30% of the width of the second groove portion 122, Fn1 is 14 or less, and/or Fn2 is 30 or more. In this case, the cooling rate of material B can be further reduced. Therefore, it is easy to adjust the cooling stop temperature to a desired temperature. Furthermore, the temperature variation of the material B during hot press molding can be reduced.
　［本実施形態の金型１０の他の形態］
　［金型１０の第１成形面１１０及び第２成形面１２０の形状について］
　本実施形態による金型１０は、上記構成に限定されない。例えば、金型１０は図２に示す形状に限定されない。金型１０の第１成形面１１０及び第２成形面１２０は長手方向に湾曲していてもよい。また、金型１０の上型１１の第１成形面１１０の長手方向（Ｌ方向）に垂直な断面形状は、凹形状に限定されない。下型１２の第２成形面１２０の長手方向（Ｌ方向）に垂直な断面形状は、凸形状に限定されない。上型１１の第１成形面１１０が、下型１２の第２成形面１２０と嵌合すれば、第１成形面１１０及び第２成形面１２０の形状は特に限定されない。 [Another form of the mold 10 of the present embodiment]
[Regarding the shape of the first molding surface 110 and the second molding surface 120 of the mold 10]
The mold 10 according to this embodiment is not limited to the configuration described above. For example, mold 10 is not limited to the shape shown in FIG. The first molding surface 110 and the second molding surface 120 of the mold 10 may be curved in the longitudinal direction. Moreover, the cross-sectional shape perpendicular to the longitudinal direction (L direction) of the first molding surface 110 of the upper mold 11 of the mold 10 is not limited to a concave shape. The cross-sectional shape perpendicular to the longitudinal direction (L direction) of the second molding surface 120 of the lower mold 12 is not limited to a convex shape. As long as the first molding surface 110 of the upper mold 11 fits with the second molding surface 120 of the lower mold 12, the shapes of the first molding surface 110 and the second molding surface 120 are not particularly limited.
　［第１成形面１１０の第１緩冷却領域１１３及び第２成形面１２０の第２緩冷却領域１２３の配置について］
　また、第１成形面１１０の第１緩冷却領域１１３の配置は特に限定されない。同様に、第２成形面１２０の第２緩冷却領域１２３の配置は特に限定されない。第１成形面１１０が第１緩冷却領域１１３を含み、第２成形面１２０が第２緩冷却領域１２３を含んでいればよい。 [Arrangement of First Slow Cooling Area 113 of First Molding Surface 110 and Second Slow Cooling Area 123 of Second Molding Surface 120]
Also, the arrangement of the first slow cooling region 113 on the first molding surface 110 is not particularly limited. Similarly, the arrangement of the second slow cooling region 123 on the second molding surface 120 is not particularly limited. It is sufficient that the first molding surface 110 includes the first slow cooling region 113 and the second molding surface 120 includes the second slow cooling region 123 .
　例えば、第１緩冷却領域１１３及び第２緩冷却領域１２３は、図２に示される形態に限定されない。図１１は、本実施形態による金型１０の図２とは異なる他の一例を示す斜視図である。図１１に示すように、金型１０の上型１１の第１成形面１１０の凹部の溝底面全面に第１緩冷却領域１１３が配置されていてもよい。金型１０の下型１２の第２成形面１２０の凸部の上面全面に、第２緩冷却領域１２３が配置されていてもよい。 For example, the first slow cooling region 113 and the second slow cooling region 123 are not limited to the form shown in FIG. FIG. 11 is a perspective view showing another example different from FIG. 2 of the mold 10 according to this embodiment. As shown in FIG. 11 , the first slow cooling region 113 may be arranged on the entire bottom surface of the groove of the concave portion of the first molding surface 110 of the upper mold 11 of the mold 10 . A second slow cooling region 123 may be arranged on the entire upper surface of the convex portion of the second molding surface 120 of the lower mold 12 of the mold 10 .
　図１２は、本実施形態による金型１０の図２及び図１１とは異なる他の一例を示す斜視図である。図１２に示すように、金型１０の上型１１の第１成形面１１０の凹部の側面の一部に、第１緩冷却領域１１３が配置されていてもよい。金型１０の下型１２の第２成形面１２０の凸部の側面の一部に、第２緩冷却領域１２３が配置されていてもよい。 FIG. 12 is a perspective view showing another example of the mold 10 according to this embodiment, which is different from FIGS. 2 and 11. FIG. As shown in FIG. 12 , a first slow cooling region 113 may be arranged on a part of the side surface of the concave portion of the first molding surface 110 of the upper mold 11 of the mold 10 . A second slow cooling region 123 may be arranged on a part of the side surface of the convex portion of the second molding surface 120 of the lower mold 12 of the mold 10 .
　図１３は、本実施形態による金型１０の図２、図１１及び図１２と異なる他の一例を示す斜視図である。図２、図１１及び図１２では、第１成形面１１０は、第１緩冷却領域１１３と第１急冷領域１１４とを含む。そして、第２成形面１２０は、第２緩冷却領域１２３と第２急冷領域１２４を含む。これに対して、図１３に示すとおり、第１成形面１１０全体が第１緩冷却領域１１３であってもよい。また、第２成形面１２０全体が第２緩冷却領域１２３であってもよい。 FIG. 13 is a perspective view showing another example different from FIGS. 2, 11 and 12 of the mold 10 according to this embodiment. 2, 11 and 12, the first molding surface 110 includes a first slow cooling zone 113 and a first quenching zone 114. In FIGS. The second forming surface 120 includes a second slow cooling region 123 and a second rapid cooling region 124 . On the other hand, as shown in FIG. 13 , the entire first molding surface 110 may be the first slow cooling region 113 . Also, the second molding surface 120 as a whole may be the second slow cooling region 123 .
　以上のとおり、第１成形面１１０が第１緩冷却領域１１３を含み、第２成形面１２０が第２緩冷却領域１２３を含んでいれば、第１成形面１１０中の第１緩冷却領域１１３の位置、及び、第２成形面１２０中の第２緩冷却領域１２３の位置は、特に限定されない。しかしながら、熱間プレス成形時に上型１１及び下型１２が素材Ｂと接触して素材Ｂをプレスしている状態のとき、第１緩冷却領域１１３の少なくとも一部は、第２緩冷却領域１２３の少なくとも一部と、互いに対向して配置される。 As described above, if the first molding surface 110 includes the first slow cooling region 113 and the second molding surface 120 includes the second slow cooling region 123, the first slow cooling region 113 in the first molding surface 110 and the position of the second slow cooling region 123 in the second molding surface 120 are not particularly limited. However, when the upper mold 11 and the lower mold 12 are in contact with the material B and are pressing the material B during hot press molding, at least part of the first slow cooling area 113 is replaced by the second slow cooling area 123 and at least a portion of the are arranged opposite each other.
　本実施形態ではさらに、第１緩冷却領域１１３は、第１リブ部１１１及び第１溝部１１２が形成されている領域のうち一部の領域として定義することもできる。同様に、第２緩冷却領域１２３は、第２リブ部１２１及び第２溝部１２２が形成されている領域のうち一部の領域として定義することもできる。要するに、本実施形態では、第１成形面１１０のうち少なくとも一部の領域において、第１リブ部１１１の幅が、第１溝部１１２の幅よりも狭く、第２成形面１２０のうち少なくとも一部の領域において、第２リブ部１２１の幅が第２溝部１２２の幅よりも狭い。 Further, in the present embodiment, the first slow cooling region 113 can also be defined as a part of the region in which the first rib portion 111 and the first groove portion 112 are formed. Similarly, the second slow cooling region 123 can also be defined as a partial region of the region where the second rib portion 121 and the second groove portion 122 are formed. In short, in the present embodiment, the width of the first rib portion 111 is narrower than the width of the first groove portion 112 in at least a partial region of the first molding surface 110, and the width of the second molding surface 120 is at least partially wide. , the width of the second rib portion 121 is narrower than the width of the second groove portion 122 .
　［第１リブ部１１１及び第２リブ部１２１の延在方向について］
　本実施形態において、第１リブ部１１１の延在方向、及び、第２リブ部１２１の延在方向は、特に限定されない。例えば、第１リブ部１１１及び第２リブ部１２１は、図５Ａ及び図６に示されるＬ方向に延在していなくてもよい。図１４は、図３の領域１００を拡大した模式図のうち、図５Ａとは異なる他の一例である。図１５は図１４の線分ＸＶ－ＸＶでの断面図である。図１４及び図１５を参照して、本実施形態では、第１リブ部１１１、第１溝部１１２、第２リブ部１２１、及び、第２溝部１２２は、いずれもＷ方向に延在し、Ｌ方向に並んでいる。この場合、第１リブ部１１１の幅、第１溝部１１２の幅、第２リブ部１２１の幅、及び、第２溝部１２２の幅は、いずれも、金型１０のＬ方向の幅を意味する。 [Regarding the extending direction of the first rib portion 111 and the second rib portion 121]
In the present embodiment, the extending direction of the first rib portion 111 and the extending direction of the second rib portion 121 are not particularly limited. For example, the first rib portion 111 and the second rib portion 121 do not have to extend in the L direction shown in FIGS. 5A and 6 . FIG. 14 is another example different from FIG. 5A among schematic diagrams in which the region 100 in FIG. 3 is enlarged. 15 is a cross-sectional view taken along the line segment XV--XV of FIG. 14. FIG. 14 and 15, in the present embodiment, the first rib portion 111, the first groove portion 112, the second rib portion 121, and the second groove portion 122 all extend in the W direction, and the L lined up in the direction In this case, the width of the first rib portion 111, the width of the first groove portion 112, the width of the second rib portion 121, and the width of the second groove portion 122 all mean the width of the mold 10 in the L direction. .
　熱間プレス成形では、上型１１がスライド３とともに、Ｖ方向に移動する。その結果、素材Ｂは、上型１１の第１成形面１１０と、下型１２の第２成形面１２０とによって、熱間プレス成形される。第１成形面１１０及び第２成形面１２０が図２に示す形状を有する場合、熱間プレス成形により、素材Ｂのメタルフローは、Ｗ方向に進む。つまり、領域１００において、素材Ｂは第１成形面１１０、第２成形面１２０に対して、Ｗ方向に摺動する。 In hot press molding, the upper mold 11 moves in the V direction together with the slide 3. As a result, the material B is hot press-molded by the first molding surface 110 of the upper mold 11 and the second molding surface 120 of the lower mold 12 . When the first molding surface 110 and the second molding surface 120 have the shapes shown in FIG. 2, the metal flow of the material B proceeds in the W direction by hot press molding. That is, in the region 100, the material B slides in the W direction with respect to the first molding surface 110 and the second molding surface 120. As shown in FIG.
　図１４及び図１５に示すように、第１リブ部１１１、第１溝部１１２、第２リブ部１２１、及び、第２溝部１２２がいずれもＷ方向に延在する場合、素材Ｂが第１リブ部１１１及び／又は第２リブ部１２１からの摩擦抵抗を受けにくく、素材Ｂは第１リブ部１１１及び／又は第２リブ部１２１に対して摺動しやすい。そのため、素材Ｂの表面に疵が形成されるのを抑制することができる。 As shown in FIGS. 14 and 15, when the first rib portion 111, the first groove portion 112, the second rib portion 121, and the second groove portion 122 all extend in the W direction, the material B is the first rib. The material B is less likely to receive frictional resistance from the portion 111 and/or the second rib portion 121 and easily slides on the first rib portion 111 and/or the second rib portion 121 . Therefore, formation of flaws on the surface of the material B can be suppressed.
　このように、第１リブ部１１１、第１溝部１１２、第２リブ部１２１、及び、第２溝部１２２が、熱間プレス成形途中の過程での素材Ｂの摺動方向に延在している場合、熱間プレス成形途中の過程において、素材Ｂの表面に疵が形成されるのを抑制することができる。 Thus, the first rib portion 111, the first groove portion 112, the second rib portion 121, and the second groove portion 122 extend in the sliding direction of the material B during the hot press forming process. In this case, it is possible to suppress the formation of flaws on the surface of the material B during the hot press forming process.
　［第１リブ部１１１及び第２リブ部１２１の配置の関係について］
　本実施形態において、第１リブ部１１１と第２リブ部１２１との配置は、図５Ａ及び図６に示されるように、金型１０が閉じた状態において、完全に重複していなくてもよい。図１６は、図３の領域１００を拡大した模式図のうち、図５Ａ及び図１４とは異なる他の一例である。図１７は、図１６の領域１００を第１緩冷却領域１１３の法線方向から見て、リブ部のみを図示した模式図である。例えば、図１６及び図１７を参照して、金型１０が閉じた状態において、第１リブ部１１１と第２リブ部１２１とが、平行に配置され、互いにずれた状態で重複していてもよい。このように、第１リブ部１１１と第２リブ部１２１とは、少なくとも一部が重複すればよい。 [Regarding the arrangement relationship between the first rib portion 111 and the second rib portion 121]
In this embodiment, the arrangement of the first rib portion 111 and the second rib portion 121 may not completely overlap when the mold 10 is closed, as shown in FIGS. 5A and 6. . FIG. 16 is another example different from FIGS. 5A and 14 in a schematic diagram in which the region 100 in FIG. 3 is enlarged. FIG. 17 is a schematic diagram showing only the rib portion when the region 100 of FIG. 16 is viewed from the normal direction of the first slow cooling region 113 . For example, referring to FIGS. 16 and 17, when the mold 10 is closed, even if the first rib portion 111 and the second rib portion 121 are arranged in parallel and overlap with each other in a displaced state, good. Thus, the first rib portion 111 and the second rib portion 121 may at least partially overlap each other.
　本実施形態において、第１リブ部１１１と第２リブ部１２１との配置は、図５Ａ及び図１６に示されるように、同じ向きに延在していなくてもよい。図１８は、図３の領域１００を拡大した模式図のうち、図５Ａ、図１４及び図１６とは異なる他の一例である。図１９は、図１８の領域１００を第１緩冷却領域の法線方向から見て、リブ部のみを図示した模式図である。例えば、図１８及び図１９に示されるように、複数の第１溝部１１２と複数の第１リブ部１１１とがいずれもＬ方向に延在し、複数の第２溝部１２２と複数の第２リブ部１２１とがいずれもＷ方向に延在してもよい。この場合であっても、図１９を参照して、金型１０が閉じた状態において、第１リブ部１１１と、第２リブ部１２１とは、少なくとも一部が重複する。 In this embodiment, the arrangement of the first rib portion 111 and the second rib portion 121 does not have to extend in the same direction, as shown in FIGS. 5A and 16 . FIG. 18 is another example different from FIGS. 5A, 14, and 16 in the enlarged schematic diagram of the region 100 in FIG. FIG. 19 is a schematic diagram showing only the rib portion when viewing the region 100 of FIG. 18 from the normal direction of the first slow cooling region. For example, as shown in FIGS. 18 and 19, the plurality of first grooves 112 and the plurality of first ribs 111 both extend in the L direction, and the plurality of second grooves 122 and the plurality of second ribs 121 may extend in the W direction. Even in this case, referring to FIG. 19, first rib portion 111 and second rib portion 121 at least partially overlap when mold 10 is closed.
　［第１緩冷却領域１１３及び第２緩冷却領域１２３について］
　本実施形態の第１緩冷却領域１１３及び第２緩冷却領域１２３は、冷却媒体を第１緩冷却領域１１３及び第２緩冷却領域１２３の表面に供給するための供給口を有さない方が好ましい。仮に、第１緩冷却領域１１３及び第２緩冷却領域１２３が供給口を有する場合、供給口に通じる金型１０（上型１１、下型１２）内部の配管内に滞留している空気により、第１緩冷却領域１１３及び第２緩冷却領域１２３のうち供給口を有する部分で、素材Ｂが過剰に抜熱されやすくなる。そのため、素材Ｂの温度ばらつきが助長される可能性がある。 [Regarding the first slow cooling region 113 and the second slow cooling region 123]
The first slow cooling region 113 and the second slow cooling region 123 of the present embodiment preferably do not have supply ports for supplying the cooling medium to the surfaces of the first slow cooling region 113 and the second slow cooling region 123. preferable. If the first slow cooling region 113 and the second slow cooling region 123 have supply ports, the air remaining in the pipes inside the mold 10 (upper mold 11, lower mold 12) leading to the supply ports Excessive heat removal from the material B is facilitated in the portions of the first slow-cooling region 113 and the second slow-cooling region 123 that have the supply port. Therefore, the temperature variation of the material B may be promoted.
　一方、上型１１及び下型１２は、内部に冷却媒体を通す冷却路を有してもよい。この場合、熱間プレス成形中の上型１１及び下型１２の温度を、十分に低く保つことができる。 On the other hand, the upper mold 11 and the lower mold 12 may have cooling passages through which a cooling medium passes. In this case, the temperatures of the upper mold 11 and the lower mold 12 during hot press molding can be kept sufficiently low.
　［金型１０を用いた熱間プレス成形品の製造方法］
　金型１０を用いた熱間プレス成形による熱間プレス成形品の製造方法について説明する。本実施形態による熱間プレス成形品の製造方法は、次の工程を備える。
　・準備工程
　・加熱工程
　・熱間プレス成形工程
　・離型工程
　以下、各工程について説明する。 [Manufacturing method of hot press-formed product using mold 10]
A method for manufacturing a hot press-formed product by hot press-forming using the mold 10 will be described. A method for manufacturing a hot press-formed product according to the present embodiment includes the following steps.
・Preparation process ・Heating process ・Hot press molding process ・Mold releasing process Each process will be described below.
　［準備工程］
　準備工程では、所望の化学組成を有する素材Ｂを準備する。本実施形態において、素材Ｂは特に限定されない。素材Ｂは例えば、鋼板である。素材Ｂが鋼板である場合、鋼板の種類は特に限定されない。素材Ｂは例えば、めっき処理等の表面処理がされた鋼板であってもよく、めっき処理等の表面処理がされていない鋼板（いわゆる裸材）であってもよい。めっき処理を実施する場合、めっき処理とは、溶融亜鉛めっき処理であってもよく、合金化溶融亜鉛めっき処理であってもよく、アルミニウムめっき処理であってもよい。 [Preparation process]
In the preparation step, a material B having a desired chemical composition is prepared. In this embodiment, the material B is not particularly limited. Material B is, for example, a steel plate. When the material B is a steel plate, the type of steel plate is not particularly limited. The material B may be, for example, a steel plate subjected to surface treatment such as plating, or may be a steel plate not subjected to surface treatment such as plating (so-called bare material). When the plating treatment is performed, the plating treatment may be a hot dip galvanizing treatment, an alloyed hot dip galvanizing treatment, or an aluminum plating treatment.
　素材Ｂの母材鋼板の化学組成は、上述のとおり、特に限定されない。素材Ｂの母材鋼板は例えば、質量％で、Ｃ：０．１０～０．６０％、Ｓｉ：０～５．０％、Ｍｎ：０～５．０％、Ｐ：０．１００％以下、Ｓ：０．１００％以下、Ｎ：０．１００％以下、Ｏ：０．１００％以下、Ａｌ：０～１．０％、Ｃｒ：０～３．０％、Ｍｏ：０～５．０％、Ｖ：０～２．０％、Ｎｂ：０～１．０％、Ｔｉ：０～１．０％、Ｂ：０～１．０％、Ｃａ：０～１．０％、Ｍｇ：０～１．０％、Ｚｒ：０～１．０％、希土類元素：０～１．０％、Ｃｏ：０～５．０％、Ｗ：０～５．０％、Ｎｉ：０～３．０％、Ｃｕ：０～３．０％、及び、残部がＦｅ及び不純物からなる化学組成を有していてもよい。ここで、不純物とは、鋼材を工業的に製造する際に、原料としての鉱石、スクラップ、又は製造環境などから混入される元素であって、本実施形態による熱間プレス成形品に悪影響を与えない範囲で許容される元素を意味する。 The chemical composition of the base material steel plate of material B is not particularly limited as described above. The base material steel plate of material B, for example, in mass%, C: 0.10 to 0.60%, Si: 0 to 5.0%, Mn: 0 to 5.0%, P: 0.100% or less, S: 0.100% or less, N: 0.100% or less, O: 0.100% or less, Al: 0 to 1.0%, Cr: 0 to 3.0%, Mo: 0 to 5.0% , V: 0-2.0%, Nb: 0-1.0%, Ti: 0-1.0%, B: 0-1.0%, Ca: 0-1.0%, Mg: 0- 1.0%, Zr: 0-1.0%, Rare earth elements: 0-1.0%, Co: 0-5.0%, W: 0-5.0%, Ni: 0-3.0% , Cu: 0-3.0%, and the balance being Fe and impurities. Here, the impurities are elements that are mixed from ore, scrap, or the manufacturing environment as raw materials when industrially manufacturing steel materials, and have an adverse effect on the hot press-formed product according to the present embodiment. means an element that is permissible within the range of
　素材Ｂの厚さは、特に限定されないが、得ようとする熱間プレス成形品の特性に応じて選択される。素材Ｂの厚さは例えば、０．６～３．２ｍｍである。素材Ｂの機械的特性も特に限定されない。得ようとする熱間プレス成形品の特性に応じて、素材Ｂの機械的特性は適宜選択される。素材Ｂの引張強度は例えば、４００ＭＰａ以上であってもよい。 The thickness of material B is not particularly limited, but is selected according to the characteristics of the hot press-formed product to be obtained. The thickness of the material B is, for example, 0.6-3.2 mm. The mechanical properties of material B are also not particularly limited. The mechanical properties of the material B are appropriately selected according to the properties of the hot press-formed product to be obtained. The tensile strength of material B may be, for example, 400 MPa or more.
　素材Ｂを準備する方法は、特に限定されない。例えば、上述の化学組成を有する溶鋼から、公知の製造方法により素材Ｂを製造してもよい。第三者により製造された素材Ｂを購入することによって準備してもよい。 The method of preparing material B is not particularly limited. For example, the raw material B may be manufactured from molten steel having the chemical composition described above by a known manufacturing method. It may be prepared by purchasing material B manufactured by a third party.
　［加熱工程］
　加熱工程では、準備された素材ＢをＡｃ３点以上の温度に加熱する。加熱温度がＡｃ３点未満であれば、素材Ｂがオーステナイト単相にならない。この場合、熱間プレス成形工程で素材Ｂを冷却したとき、素材Ｂのうち、第１急冷領域１１４及び第２急冷領域１２４に挟まれた領域において、硬質相（マルテンサイト及び／又はベイナイト）の形成が不十分となる。そのため、十分な強度が得られない場合がある。加熱温度がＡｃ３点以上であれば、熱間プレス成形工程前の素材Ｂはオーステナイト単相となる。そのため、熱間プレス成形工程で素材Ｂを冷却したとき、素材Ｂのうち、第１急冷領域１１４及び第２急冷領域１２４に挟まれた領域において、硬質相が十分に形成される。その結果当該領域の強度を高めることができる。 [Heating process]
In the heating step, the prepared material B is heated to a temperature of Ac3 or higher. If the heating temperature is less than the Ac3 point, the material B will not become an austenite single phase. In this case, when the material B is cooled in the hot press forming process, the hard phase (martensite and/or bainite) is formed in the area sandwiched between the first quenched region 114 and the second quenched region 124 in the material B. Insufficient formation. Therefore, sufficient strength may not be obtained. If the heating temperature is A c3 point or more, the material B before the hot press forming process becomes austenite single phase. Therefore, when the material B is cooled in the hot press forming process, a hard phase is sufficiently formed in the area of the material B sandwiched between the first quenching region 114 and the second quenching region 124 . As a result, the strength of the region can be increased.
　好ましくは、加熱温度は９５０℃未満とする。この場合、素材Ｂの加熱時間を短くすることができ、生産性を高めることができる。さらに、加熱に必要な燃料及び電力を削減できるため、製造コストを抑えることができる。 The heating temperature is preferably less than 950°C. In this case, the heating time of the material B can be shortened, and the productivity can be improved. Furthermore, since the fuel and power required for heating can be reduced, manufacturing costs can be suppressed.
　加熱工程において、素材Ｂを加熱する方法は特に限定されない。例えば、電気炉、ガス炉、遠赤外炉、近赤外炉等、加熱炉を用いて素材Ｂを加熱してもよい。また、通電加熱装置や、高周波誘導加熱装置等を用いて素材Ｂを加熱してもよい。加熱工程において、素材Ｂを加熱する方法は限定されず、公知の加熱方法を適宜選択することができる。 In the heating process, the method of heating material B is not particularly limited. For example, the material B may be heated using a heating furnace such as an electric furnace, gas furnace, far-infrared furnace, or near-infrared furnace. Alternatively, the material B may be heated using an electric heating device, a high-frequency induction heating device, or the like. In the heating step, the method for heating the material B is not limited, and a known heating method can be appropriately selected.
　［熱間プレス成形工程］
　熱間プレス成形工程では、Ａｃ３点以上に加熱された素材Ｂを、上述の金型１０を用いて熱間プレス成形する。熱間プレス成形工程では、加熱工程で加熱された素材Ｂが下型１２の第２成形面１２０の上に載置される。その後、図３に示すように、上型１１を下型１２に相対的に接近させて、金型１０を閉じる。このとき、素材Ｂは上型１１の第１成形面１１０及び下型１２の第２成形面１２０と接触する。換言すれば、素材Ｂは、上型１１の第１成形面１１０及び下型１２の第２成形面１２０に挟まれる。上型１１及び下型１２により、素材Ｂに対して熱間プレス成形を実施する。 [Hot press molding process]
In the hot press-molding step, the material B heated to the Ac 3 point or higher is hot press-molded using the above-described mold 10 . In the hot press molding process, the material B heated in the heating process is placed on the second molding surface 120 of the lower mold 12 . After that, as shown in FIG. 3, the upper mold 11 is brought relatively closer to the lower mold 12, and the mold 10 is closed. At this time, the material B contacts the first molding surface 110 of the upper mold 11 and the second molding surface 120 of the lower mold 12 . In other words, the material B is sandwiched between the first molding surface 110 of the upper mold 11 and the second molding surface 120 of the lower mold 12 . Hot press molding is performed on the material B by the upper mold 11 and the lower mold 12 .
　なお、本実施形態による熱間プレス成形工程では、熱間プレス成形時に素材Ｂを、冷却媒体を用いて冷却しない。代わりに、熱間プレス成形時に素材Ｂと接触する金型１０により素材Ｂを抜熱する。金型１０が閉じているとき、第１緩冷却領域１１３では、上型１１の第１成形面１１０の第１リブ部１１１と素材Ｂとが接触する。さらに、第２緩冷却領域１２３では、下型１２の第２成形面１２０の第２リブ部１２１と素材Ｂとが接触する。このとき、上型１１及び下型１２は、素材Ｂよりも十分に温度が低い。そのため、素材Ｂは第１リブ部１１１及び第２リブ部１２１によって抜熱される。上型１１及び下型１２の温度は例えば、常温（２０±１５℃）～２００℃である。 Note that in the hot press-forming process according to the present embodiment, the material B is not cooled using a cooling medium during hot press-forming. Instead, heat is removed from the material B by the mold 10 that contacts the material B during hot press molding. When the mold 10 is closed, the first rib portion 111 of the first molding surface 110 of the upper mold 11 and the material B are in contact with each other in the first slow cooling region 113 . Furthermore, the second rib portion 121 of the second molding surface 120 of the lower mold 12 and the material B are in contact with each other in the second slow cooling region 123 . At this time, the temperature of the upper mold 11 and the lower mold 12 is sufficiently lower than that of the material B. Therefore, the heat of the material B is removed by the first rib portion 111 and the second rib portion 121 . The temperature of the upper mold 11 and the lower mold 12 is, for example, room temperature (20±15°C) to 200°C.
　［離型工程］
　離型工程では、熱間プレス成形された素材Ｂを、金型１０から離型して、熱間プレス成形品を製造する。ここで、離型工程において、金型１０から離型されたときの素材Ｂ（熱間プレス成形品）の温度を、冷却停止温度と定義する。例えば、冷却停止温度が熱間プレス成形品のＭｆ点～Ｍｓ点の間、又は、Ｍｓ点超～５００℃の間であれば、熱間プレス成形品のミクロ組織として、硬質相からなる組織、又は、硬質相及び残留オーステナイトからなる組織が得られる。この場合、得られた熱間プレス成形品は優れた衝撃吸収能を有する。したがって、好ましくは、本実施形態による離型工程では、素材Ｂのうち、第１緩冷却領域１１３及び第２緩冷却領域１２３に挟まれた領域の温度が、素材Ｂの化学組成から求められるＭｆ点～Ｍｓ点の間、又は、Ｍｓ点超～５００℃の間であるときに、素材Ｂを金型１０から離型する。 [Mold release process]
In the mold release step, the hot press-formed material B is released from the mold 10 to produce a hot press-formed product. Here, in the mold release step, the temperature of the material B (hot press-formed product) when released from the mold 10 is defined as the cooling stop temperature. For example, if the cooling stop temperature is between the Mf point and Ms point of the hot press-formed product, or between the Ms point and above and 500 ° C., the microstructure of the hot press-formed product is a structure consisting of a hard phase, Alternatively, a structure consisting of a hard phase and retained austenite is obtained. In this case, the resulting hot press-formed product has excellent impact absorption ability. Therefore, preferably, in the mold release step according to the present embodiment, the temperature of the region sandwiched between the first slow cooling region 113 and the second slow cooling region 123 of the material B is Mf The material B is released from the mold 10 when the temperature is between the point and the Ms point, or when the temperature is above the Ms point and between 500°C.
　なお、素材ＢのＭｓ点及びＭｆ点は、素材Ｂの化学組成によって異なる。そのため、素材Ｂにおいて、硬質相からなる組織、又は、硬質相及び残留オーステナイトからなる組織を得ようとする場合、素材Ｂの化学組成によって、好ましい冷却停止温度は異なる。しかしながら、金型１０を用いた熱間プレス成形品の製造方法によれば、第１緩冷却領域１１３と第２緩冷却領域１２３とに形成された第１リブ部１１１、第１溝部１１２、第２リブ部１２１、及び、第２溝部１２２の幅及び高さ、及び、素材Ｂの化学組成に基づいて、熱伝達シミュレーションにより、素材Ｂのうち、第１緩冷却領域１１３及び第２緩冷却領域１２３に挟まれた領域での冷却速度、温度の経時変化、及び、熱間プレス成形後所定時間経過後の温度分布を求めることができる。したがって、これらの熱伝達シミュレーションにより、好ましい冷却停止温度、又は、熱間プレス成形を開始してから離型するまでの時間、を求めることができる。そのため、本実施形態による金型１０によれば、素材Ｂの化学組成に応じて、硬質相からなる組織、又は、硬質相及び残留オーステナイトからなる組織を有する熱間プレス成形品を、熱間プレス成形によって製造することができる。 The Ms point and Mf point of material B differ depending on the chemical composition of material B. Therefore, when attempting to obtain a structure consisting of a hard phase or a structure consisting of a hard phase and retained austenite in the material B, the preferred cooling stop temperature differs depending on the chemical composition of the material B. However, according to the method for manufacturing a hot press-formed product using the mold 10, the first rib portion 111, the first groove portion 112, the second Based on the width and height of the two rib portions 121 and the second groove portions 122 and the chemical composition of the material B, a heat transfer simulation was performed to determine the first slow cooling region 113 and the second slow cooling region of the material B. It is possible to obtain the cooling rate in the region sandwiched by 123, the change in temperature over time, and the temperature distribution after a predetermined time has elapsed after hot press forming. Therefore, from these heat transfer simulations, it is possible to obtain a preferable cooling stop temperature or the time from the start of hot press forming to the release of the mold. Therefore, according to the mold 10 according to the present embodiment, a hot press-formed product having a structure consisting of a hard phase or a structure consisting of a hard phase and retained austenite can be hot-pressed according to the chemical composition of the material B. It can be manufactured by molding.
　［その他の工程］
　本実施形態による熱間プレス成形品の製造方法はさらに、上記以外の他の製造工程を含んでもよい。例えば、本実施形態による熱間プレス成形品の製造方法は、離型工程後に、５００℃以下の温度域での加熱保持工程を実施してもよい。 [Other processes]
The method for manufacturing a hot press-formed product according to the present embodiment may further include manufacturing steps other than those described above. For example, in the method for manufacturing a hot press-formed product according to the present embodiment, a heating and holding step in a temperature range of 500° C. or less may be performed after the mold release step.
　加熱保持工程では、離型工程後の熱間プレス成形品に対して、５００℃以下の温度域での加熱保持を実施する。具体的には、金型１０から離型して製造された熱間プレス成形品を、１００～５００℃の加熱温度で保持する。この場合、加熱保持により、熱間プレス成形品のミクロ組織中の硬質相から残留オーステナイトに炭素を分配することができる。残留オーステナイトでの炭素が濃化するため、残留オーステナイトの生成が促進される。その結果、熱間プレス成形品内で、残留オーステナイトの割合が増える。この場合、衝突変形時に残留オーステナイトがマルテンサイトに変態して、熱間プレス成形品の延性が向上する（いわゆるＴＲＩＰ（ＴＲａｎｓｆｏｒｍａｔｉｏｎ　Ｉｎｄｕｃｅｄ　Ｐｌａｓｔｉｃｉｔｙ）効果）。その結果、熱間プレス成形品の衝撃吸収能がさらに高まる。 In the heating and holding process, the hot press-formed product after the mold release process is heated and held in a temperature range of 500°C or less. Specifically, the hot press-formed product produced by releasing from the mold 10 is held at a heating temperature of 100 to 500.degree. In this case, the heat hold can distribute carbon from the hard phases to the retained austenite in the microstructure of the hot pressed part. The formation of retained austenite is accelerated due to the enrichment of carbon in the retained austenite. As a result, the proportion of retained austenite increases in the hot press-formed product. In this case, the retained austenite transforms into martensite during impact deformation, improving the ductility of the hot press-formed product (so-called TRIP (transformation induced plasticity) effect). As a result, the impact absorption capacity of the hot press-formed product is further enhanced.
　加熱保持温度の好ましい上限は４００℃である。なお、加熱保持温度は、Ｍｓ点－２０９℃以上とするのが好ましい。この場合、熱間プレス成形品の衝撃吸収能が安定してさらに高まる。したがって、Ｍｓ点－２０９℃が１００℃を超える場合、加熱保持温度の好ましい下限はＭｓ点－２０９℃である。加熱保持時間は特に限定されない。加熱保持温度での保持時間は例えば、５秒～３０分（１８００秒）とするのが好ましい。 The preferred upper limit of the heating and holding temperature is 400°C. The heating and holding temperature is preferably -209° C. or higher at the Ms point. In this case, the impact absorption capacity of the hot press-formed product is stabilized and further enhanced. Therefore, when the Ms point -209°C exceeds 100°C, the preferable lower limit of the heating and holding temperature is the Ms point -209°C. The heating holding time is not particularly limited. The holding time at the heating and holding temperature is preferably 5 seconds to 30 minutes (1800 seconds), for example.
　以上、本開示の実施の形態を説明した。しかしながら、上述した実施の形態は本開示を実施するための例示に過ぎない。したがって、本開示は上述した実施の形態に限定されることなく、その趣旨を逸脱しない範囲内で上述した実施の形態を適宜変更して実施することができる。 The embodiment of the present disclosure has been described above. However, the above-described embodiments are merely examples for implementing the present disclosure. Therefore, the present disclosure is not limited to the above-described embodiments, and the above-described embodiments can be modified as appropriate without departing from the scope of the present disclosure.
　　１　熱間プレス装置
　　１０　金型
　　１１　上型
　　１１０　第１成形面
　　１１１　第１リブ部
　　１１２　第１溝部
　　１１３　第１緩冷却領域
　　１２　下型
　　１２０　第２成形面
　　１２１　第２リブ部
　　１２２　第２溝部
　　１２３　第２緩冷却領域 1 hot press device 10 mold 11 upper mold 110 first molding surface 111 first rib 112 first groove 113 first slow cooling region 12 lower mold 120 second molding surface 121 second rib 122 second groove 123 second 2 slow cooling region

Claims (9)

  1. 　素材に対して熱間プレス成形を実施するための金型であって、
    　第１成形面を有する上型と、
    　熱間プレス成形時において、前記第１成形面と対向して配置され、前記第１成形面とともに前記素材を熱間プレス成形する第２成形面を有する下型とを備え、
    　前記第１成形面は、
    　複数の第１リブ部と複数の第１溝部とを有する第１緩冷却領域を含み、
    　複数の前記第１リブ部は、前記第１リブ部の幅方向に配列され、
    　複数の前記第１溝部は、前記第１溝部の幅方向に配列され、
    　前記第１リブ部は、隣り合う前記第１溝部の間に形成されており、
    　前記第１リブ部の幅は、前記第１溝部の幅よりも狭く、
    　前記第２成形面は、
    　複数の第２リブ部と複数の第２溝部とを有する第２緩冷却領域を含み、
    　複数の前記第２リブ部は、前記第２リブ部の幅方向に配列され、
    　複数の前記第２溝部は、前記第２溝部の幅方向に配列され、
    　前記第２リブ部は、隣り合う前記第２溝部の間に形成されており、
    　前記第２リブ部の幅は、前記第２溝部の幅よりも狭く、
    　熱間プレス成形時において、前記第１緩冷却領域及び前記第２緩冷却領域を、前記第１緩冷却領域の法線方向から見たとき、
    　前記第１リブ部と前記第２リブ部とは、少なくとも一部が重複している、
    　金型。     A mold for performing hot press molding on a material,
    an upper mold having a first molding surface;
    a lower mold having a second molding surface that is arranged to face the first molding surface and hot press molds the material together with the first molding surface during hot press molding;
    The first molding surface is
    including a first slow cooling region having a plurality of first ribs and a plurality of first grooves;
    The plurality of first rib portions are arranged in the width direction of the first rib portion,
    The plurality of first grooves are arranged in the width direction of the first grooves,
    The first rib portion is formed between the adjacent first groove portions,
    The width of the first rib portion is narrower than the width of the first groove portion,
    The second molding surface is
    including a second slow cooling region having a plurality of second ribs and a plurality of second grooves;
    The plurality of second rib portions are arranged in the width direction of the second rib portion,
    The plurality of second grooves are arranged in the width direction of the second grooves,
    The second rib portion is formed between the adjacent second groove portions,
    The width of the second rib portion is narrower than the width of the second groove portion,
    During hot press forming, when the first slow cooling region and the second slow cooling region are viewed from the normal direction of the first slow cooling region,
    At least a portion of the first rib portion and the second rib portion overlap,
    Mold.
  2. 　請求項１に記載の金型であって、
    　熱間プレス成形時において、前記第１緩冷却領域及び前記第２緩冷却領域を、前記第１緩冷却領域の法線方向から見たとき、
    　前記第１リブ部と前記第２リブ部とは、同じ方向に延びており、
    　前記第１溝部と前記第２溝部とは、同じ方向に延びている、
    　金型。     A mold according to claim 1,
    During hot press forming, when the first slow cooling region and the second slow cooling region are viewed from the normal direction of the first slow cooling region,
    The first rib portion and the second rib portion extend in the same direction,
    The first groove and the second groove extend in the same direction,
    Mold.
  3. 　請求項１又は請求項２に記載の金型であって、
    　前記第１リブ部の幅は、前記第１溝部の幅の１０～５０％であり、
    　前記第２リブ部の幅は、前記第２溝部の幅の１０～５０％である、
    　金型。     The mold according to claim 1 or claim 2,
    The width of the first rib portion is 10 to 50% of the width of the first groove portion,
    The width of the second rib portion is 10 to 50% of the width of the second groove portion,
    Mold.
  4. 　請求項１～３のいずれか１項に記載の金型であって、
    　前記第１緩冷却領域の少なくとも一部において、
    　前記第１リブ部の幅は、１．０～８．０ｍｍであり、
    　前記第１リブ部の高さは、０．２～５．０ｍｍであり、
    　前記第２緩冷却領域の少なくとも一部において、
    　前記第２リブ部の幅は、１．０～８．０ｍｍであり、
    　前記第２リブ部の高さは、０．２～５．０ｍｍである、
    　金型。     The mold according to any one of claims 1 to 3,
    In at least part of the first slow cooling region,
    The width of the first rib portion is 1.0 to 8.0 mm,
    The height of the first rib portion is 0.2 to 5.0 mm,
    In at least part of the second slow cooling region,
    The width of the second rib portion is 1.0 to 8.0 mm,
    The height of the second rib portion is 0.2 to 5.0 mm,
    Mold.
  5. 　請求項２に記載の金型であって、
    　前記第１リブ部の幅は、前記第１溝部の幅の１０～５０％であり、
    　前記第２リブ部の幅は、前記第２溝部の幅の１０～５０％であり、
    　前記第１リブ部及び前記第２リブ部の各々の幅は１．０～８．０ｍｍであり、
    　前記第１リブ部及び前記第２リブ部の各々の高さは０．２～５．０ｍｍであり、
    　式（１）で定義されるＦｎ１が１４以下である、
    　金型。
    　Ｆｎ１＝Ｗｒ０．９／Ｐ００．８＋０．０５Ｈｒ　（１）
    　ここで、式（１）中のＷｒは前記第１リブ部及び前記第２リブ部の幅（ｍｍ）であり、Ｐ０＝Ｗｒ／Ｗｓであり、Ｗｓは前記第１溝部及び前記第２溝部の幅（ｍｍ）であり、Ｈｒは前記第１リブ部及び前記第２リブ部の高さ（ｍｍ）である。     A mold according to claim 2,
    The width of the first rib portion is 10 to 50% of the width of the first groove portion,
    The width of the second rib portion is 10 to 50% of the width of the second groove portion,
    The width of each of the first rib portion and the second rib portion is 1.0 to 8.0 mm,
    Each height of the first rib portion and the second rib portion is 0.2 to 5.0 mm,
    Fn1 defined by formula (1) is 14 or less,
    Mold.
    Fn1= Wr0.9 / P00.8 +0.05Hr (1)
    Here, Wr in the formula (1) is the width (mm) of the first rib portion and the second rib portion, P0 = Wr/Ws, and Ws is the width of the first groove portion and the second groove portion. is the width (mm), and Hr is the height (mm) of the first rib portion and the second rib portion.
  6. 　請求項２又は請求項５に記載の金型であって、
    　前記第１リブ部の幅は、前記第１溝部の幅の１０～５０％であり、
    　前記第２リブ部の幅は、前記第２溝部の幅の１０～５０％であり、
    　前記第１リブ部及び前記第２リブ部の各々の幅は１．０～８．０ｍｍであり、
    　前記第１リブ部及び前記第２リブ部の各々の高さは０．２～５．０ｍｍであり、
    　式（２）で定義されるＦｎ２が３０以上である、
    　金型。
    　Ｆｎ２＝Ｗｓ２×Ｈｒ０．４／Ｗｒ　（２）
    　ここで、式（２）中のＷｓは前記第１溝部及び前記第２溝部の幅（ｍｍ）であり、Ｗｒは前記第１リブ部及び前記第２リブ部の幅（ｍｍ）であり、Ｈｒは前記第１リブ部及び前記第２リブ部の高さ（ｍｍ）である。     The mold according to claim 2 or claim 5,
    The width of the first rib portion is 10 to 50% of the width of the first groove portion,
    The width of the second rib portion is 10 to 50% of the width of the second groove portion,
    The width of each of the first rib portion and the second rib portion is 1.0 to 8.0 mm,
    Each height of the first rib portion and the second rib portion is 0.2 to 5.0 mm,
    Fn2 defined by formula (2) is 30 or more,
    Mold.
    Fn2=Ws2* Hr0.4 /Wr ( 2 )
    Here, Ws in the formula (2) is the width (mm) of the first groove portion and the second groove portion, Wr is the width (mm) of the first rib portion and the second rib portion, and Hr is the height (mm) of the first rib portion and the second rib portion.
  7. 　請求項４～請求項６のいずれか１項に記載の金型であって、
    　前記第１緩冷却領域の少なくとも一部において、
    　前記第１リブ部の幅は、１．０～４．０ｍｍであり、かつ、前記第１溝部の幅の１０～３０％であり、
    　前記第２緩冷却領域の少なくとも一部において、
    　前記第２リブ部の幅は、１．０～４．０ｍｍであり、かつ、前記第２溝部の幅の１０～３０％である、
    　金型。     The mold according to any one of claims 4 to 6,
    In at least part of the first slow cooling region,
    The width of the first rib portion is 1.0 to 4.0 mm and 10 to 30% of the width of the first groove portion,
    In at least part of the second slow cooling region,
    The width of the second rib portion is 1.0 to 4.0 mm, and 10 to 30% of the width of the second groove portion.
    Mold.
  8. 　熱間プレス成形品の製造方法であって、
    　素材を準備する工程と、
    　前記準備された素材をＡｃ３点以上の温度に加熱する工程と、
    　加熱された前記素材に対して、請求項１～請求項７のいずれか１項に記載の金型により熱間プレス成形を実施する工程と、
    　熱間プレス成形された前記素材を、前記金型から離型して、熱間プレス成形品を製造する工程とを備える、
    　熱間プレス成形品の製造方法。     A method for manufacturing a hot press-formed product,
    a process of preparing materials;
    heating the prepared material to a temperature of A c 3 or higher;
    A step of performing hot press molding on the heated material using the mold according to any one of claims 1 to 7;
    A step of releasing the hot press-formed material from the mold to produce a hot press-formed product;
    A method for producing a hot press-formed product.
  9. 　請求項８に記載の熱間プレス成形品の製造方法であってさらに、
    　前記金型から離型して製造された前記熱間プレス成形品を、１００～５００℃で保持する工程とを備える、
    　熱間プレス成形品の製造方法。     A method for manufacturing a hot press-formed product according to claim 8, further comprising:
    A step of holding the hot press-formed product produced by releasing from the mold at 100 to 500 ° C.
    A method for producing a hot press-formed product.
PCT/JP2022/015965 2021-03-30 2022-03-30 Mold and method for manufacturing hot-press molded article WO2022210874A1 (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013248632A (en) * 2012-05-31 2013-12-12 Jfe Steel Corp Warm press forming method and forming die having groove shape on surface of die, which is used for the same
JP2014079790A (en) * 2012-10-17 2014-05-08 Honda Motor Co Ltd Hot press molding method and die
JP2014117735A (en) * 2012-12-18 2014-06-30 Kawasaki Heavy Ind Ltd Spinning molding device
JP2015000431A (en) * 2013-06-18 2015-01-05 Ｊｆｅスチール株式会社 Warm press forming method, forming die used in the warm press forming method, and vehicular skeleton component
JP2020116610A (en) * 2019-01-24 2020-08-06 マツダ株式会社 Hot press-working device

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013248632A (en) * 2012-05-31 2013-12-12 Jfe Steel Corp Warm press forming method and forming die having groove shape on surface of die, which is used for the same
JP2014079790A (en) * 2012-10-17 2014-05-08 Honda Motor Co Ltd Hot press molding method and die
JP2014117735A (en) * 2012-12-18 2014-06-30 Kawasaki Heavy Ind Ltd Spinning molding device
JP2015000431A (en) * 2013-06-18 2015-01-05 Ｊｆｅスチール株式会社 Warm press forming method, forming die used in the warm press forming method, and vehicular skeleton component
JP2020116610A (en) * 2019-01-24 2020-08-06 マツダ株式会社 Hot press-working device

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