US20180216219A1 - Method for Manufacturing Hot-Pressed Member - Google Patents
Method for Manufacturing Hot-Pressed Member Download PDFInfo
- Publication number
- US20180216219A1 US20180216219A1 US15/747,880 US201615747880A US2018216219A1 US 20180216219 A1 US20180216219 A1 US 20180216219A1 US 201615747880 A US201615747880 A US 201615747880A US 2018216219 A1 US2018216219 A1 US 2018216219A1
- Authority
- US
- United States
- Prior art keywords
- steel sheet
- zinc
- hot
- coated steel
- coating layer
- Prior art date
- Legal status (The legal status 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 status listed.)
- Abandoned
Links
- 238000000034 method Methods 0.000 title claims abstract description 63
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 27
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 119
- 239000010959 steel Substances 0.000 claims abstract description 119
- 239000011701 zinc Substances 0.000 claims abstract description 71
- 229910052725 zinc Inorganic materials 0.000 claims abstract description 59
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims abstract description 57
- 238000010438 heat treatment Methods 0.000 claims abstract description 39
- 238000004140 cleaning Methods 0.000 claims abstract description 33
- 238000007731 hot pressing Methods 0.000 claims abstract description 33
- 238000001816 cooling Methods 0.000 claims abstract description 19
- 230000009466 transformation Effects 0.000 claims abstract description 14
- 239000011247 coating layer Substances 0.000 claims description 44
- 239000011248 coating agent Substances 0.000 claims description 15
- 238000000576 coating method Methods 0.000 claims description 15
- 229910000990 Ni alloy Inorganic materials 0.000 claims description 13
- 239000000203 mixture Substances 0.000 claims description 10
- 239000000126 substance Substances 0.000 claims description 10
- 238000003825 pressing Methods 0.000 claims description 8
- 239000012535 impurity Substances 0.000 claims description 7
- 238000005238 degreasing Methods 0.000 description 46
- 230000007547 defect Effects 0.000 description 34
- 230000001680 brushing effect Effects 0.000 description 27
- 230000000052 comparative effect Effects 0.000 description 22
- 239000010410 layer Substances 0.000 description 21
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- 239000002699 waste material Substances 0.000 description 15
- 239000004744 fabric Substances 0.000 description 14
- 239000002904 solvent Substances 0.000 description 14
- 230000006866 deterioration Effects 0.000 description 11
- 238000005260 corrosion Methods 0.000 description 10
- 230000007797 corrosion Effects 0.000 description 9
- 239000007788 liquid Substances 0.000 description 9
- 229910052729 chemical element Inorganic materials 0.000 description 8
- 230000007423 decrease Effects 0.000 description 8
- 238000002844 melting Methods 0.000 description 8
- 230000008018 melting Effects 0.000 description 8
- 239000000463 material Substances 0.000 description 7
- 238000009713 electroplating Methods 0.000 description 6
- 238000005098 hot rolling Methods 0.000 description 5
- 230000002401 inhibitory effect Effects 0.000 description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 5
- 239000003973 paint Substances 0.000 description 5
- 238000009834 vaporization Methods 0.000 description 5
- 230000008016 vaporization Effects 0.000 description 5
- 239000007864 aqueous solution Substances 0.000 description 4
- 239000002585 base Substances 0.000 description 4
- 239000010960 cold rolled steel Substances 0.000 description 4
- 238000001035 drying Methods 0.000 description 4
- 238000011156 evaluation Methods 0.000 description 4
- 238000005096 rolling process Methods 0.000 description 4
- 239000002344 surface layer Substances 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 229910000838 Al alloy Inorganic materials 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
- 229910052782 aluminium Inorganic materials 0.000 description 3
- 239000000428 dust Substances 0.000 description 3
- 238000005246 galvanizing Methods 0.000 description 3
- 238000005244 galvannealing Methods 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 2
- 229910000611 Zinc aluminium Inorganic materials 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- HXFVOUUOTHJFPX-UHFFFAOYSA-N alumane;zinc Chemical compound [AlH3].[Zn] HXFVOUUOTHJFPX-UHFFFAOYSA-N 0.000 description 2
- 229910052787 antimony Inorganic materials 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
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- 239000013078 crystal Substances 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- VKYKSIONXSXAKP-UHFFFAOYSA-N hexamethylenetetramine Chemical compound C1N(C2)CN3CN1CN2C3 VKYKSIONXSXAKP-UHFFFAOYSA-N 0.000 description 2
- 238000011835 investigation Methods 0.000 description 2
- 150000004767 nitrides Chemical class 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 229920001778 nylon Polymers 0.000 description 2
- 238000010422 painting Methods 0.000 description 2
- 229910052698 phosphorus Inorganic materials 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 229910052717 sulfur Inorganic materials 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- 241000219307 Atriplex rosea Species 0.000 description 1
- 229920000742 Cotton Polymers 0.000 description 1
- 241000196324 Embryophyta Species 0.000 description 1
- 229910001335 Galvanized steel Inorganic materials 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 229910000861 Mg alloy Inorganic materials 0.000 description 1
- 239000004677 Nylon Substances 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 229910007567 Zn-Ni Inorganic materials 0.000 description 1
- 229910007614 Zn—Ni Inorganic materials 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 229910001563 bainite Inorganic materials 0.000 description 1
- 238000005422 blasting Methods 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000005868 electrolysis reaction Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000008397 galvanized steel Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 235000010299 hexamethylene tetramine Nutrition 0.000 description 1
- 239000004312 hexamethylene tetramine Substances 0.000 description 1
- 238000011086 high cleaning Methods 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-N hydrochloric acid Substances Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 239000003112 inhibitor Substances 0.000 description 1
- 229910000765 intermetallic Inorganic materials 0.000 description 1
- 229910000734 martensite Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 238000000053 physical method Methods 0.000 description 1
- 238000005554 pickling Methods 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 238000004506 ultrasonic cleaning Methods 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
- 239000013585 weight reducing agent Substances 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
Images
Classifications
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/26—After-treatment
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0278—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips involving a particular surface 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
- 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
- B21D22/20—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
- B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
- B21D22/20—Deep-drawing
- B21D22/26—Deep-drawing for making peculiarly, e.g. irregularly, shaped articles
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C18/00—Alloys based on zinc
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/04—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the coating material
- C23C2/06—Zinc or cadmium or alloys based thereon
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/34—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the shape of the material to be treated
- C23C2/36—Elongated material
- C23C2/40—Plates; Strips
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F17/00—Multi-step processes for surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by subclass C21D or C22F or class C25
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
- C25D5/48—After-treatment of electroplated surfaces
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
- C25D5/48—After-treatment of electroplated surfaces
- C25D5/50—After-treatment of electroplated surfaces by 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
- B21D53/00—Making other particular articles
- B21D53/88—Making other particular articles other parts for vehicles, e.g. cowlings, mudguards
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/001—Ferrous alloys, e.g. steel alloys containing N
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/28—Ferrous alloys, e.g. steel alloys containing chromium with titanium or zirconium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/60—Ferrous alloys, e.g. steel alloys containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D3/00—Electroplating: Baths therefor
- C25D3/02—Electroplating: Baths therefor from solutions
- C25D3/22—Electroplating: Baths therefor from solutions of zinc
Definitions
- the present disclosure relates to a method for manufacturing a hot-pressed member which can preferably be used for, for example, chassis and body structure members of an automobile.
- chassis and body structure members of an automobile have usually been manufactured by performing press working on steel sheets having a specified strength.
- efforts are being made to reduce the thickness of a steel sheet which is used for an automobile body by increasing the strength of the steel sheet.
- an increase in the strength of steel sheets causes a deterioration in press workability, and therefore there is an increase in the number of cases where it is difficult to form a steel sheet into desired shapes of the members.
- Patent Literature 1 proposes a working technique called hot pressing which makes it possible to realize an improvement in workability and an increase in strength at the same time by performing working and rapid cooling at the same time on a heated steel sheet by using a mold which is composed of a die and a punch.
- this hot pressing since a steel sheet is heated to a high temperature of about 950° C. before hot pressing is performed, scale (iron oxide) is generated on the surface of the steel sheet, and the flaking of the scale occurs when hot pressing is performed, which results in a problem in that a mold is damaged or the surface of a member is damaged after the hot pressing. Also, scale which remained on the surface of a member causes a deterioration in surface appearance and paint adhesiveness. Therefore, scale which is present on the surface of a member is usually removed by performing a treatment such as pickling or shot blasting. However, such a treatment makes a manufacturing process complex, and thus there is a decrease in productivity.
- chassis and body structure members of an automobile are also required to have excellent corrosion resistance.
- a hot-pressed member which is manufactured by using the process described above, is not provided with an anti-corrosion film such as a coating layer, the member is very poor in terms of corrosion resistance.
- a hot-pressing technique is desired with which the generation of scale can be inhibited when heating is performed before hot pressing and with which the corrosion resistance of a hot-pressed member can be improved, and thus a steel sheet to be hot-pressed whose surface is coated with a film such as a coating layer and a method for hot pressing which utilizes the steel sheet have been proposed.
- Patent Literature 2 discloses a method for manufacturing a hot-pressed member excellent in terms of corrosion resistance whose surface is coated with a Zn—Fe-based compound or a Zn—Fe—Al-based compound by performing hot pressing on a steel sheet, which is coated with Zn or a Zn-based alloy.
- Patent Literature 3 discloses a hot-pressed member excellent in terms of scale resistance, paint adhesiveness, after-painting corrosion resistance, and hydrogen entry resistance which is manufactured by forming a Ni diffusion region, a layer of an intermetallic compound, which is equivalent to the ⁇ phase of a Zn—Ni alloy, and a ZnO layer in the surface layer of a steel sheet.
- Patent Literature 4 discloses a steel sheet to be hot-pressed which is manufactured by forming a ZnO layer, which inhibits the vaporization of Zn, in the surface layer of a Zn-based coating layer in advance, and indicates that it is possible to obtain a hot-pressed product having good surface appearance, excellent paint adhesiveness, and excellent after-painting corrosion resistance by using the steel sheet.
- a hot-pressed member which is manufactured by using the method described in Patent Literature 2
- a zinc-coated steel sheet or a zinc-aluminum-coated steel sheet, whose coating layer has a low melting point is used, the melting of the coating layer or the vaporization of zinc which occurs in a heating process before hot pressing is significant.
- a hot-pressed member, which is finally obtained has, for example, a spotty inhomogeneous surface appearance or many white or black point-like defects. Therefore, it is difficult to obtain a hot-pressed member having a homogeneous and good surface appearance.
- Patent Literature 3 which is manufactured by using a steel sheet coated with a Zn—Ni-alloy coating layer, which has a melting point higher than that of Zn
- a hot-pressed member described in Patent Literature 3 which is manufactured by using a steel sheet coated with a Zn—Ni-alloy coating layer, which has a melting point higher than that of Zn
- Patent Literature 4 In the case where a steel sheet to be hot-pressed described in Patent Literature 4 is used, there is an improvement in the surface appearance of a hot-pressed member to some extent through the effect of a ZnO layer which is formed in the surface layer of the steel sheet. However, there is still a problem in that local point-like defects are generated in a portion in which the result of a treatment for forming a ZnO layer is inhomogeneous.
- the present disclosure has been completed in order to solve the problems of the conventional techniques described above, and an object of the present disclosure is to provide a method for manufacturing a hot-pressed member excellent in terms of surface appearance with which it is possible to stably manufacture a hot-pressed member having a homogeneous and good surface appearance without causing a significant increase in cost.
- the present inventors in order to solve the problems described above, diligently conducted investigations regarding a method for manufacturing a hot-pressed member excellent in terms of surface appearance. First, investigations regarding a state in which point-like defects are generated on the surface of a hot-pressed member were conducted. As a result, it was found that the position or number of point-like defects is not necessarily the same even if the same kind of zinc-based coated steel sheet is heated under the same condition.
- a method for manufacturing a hot-pressed member having an excellent surface appearance including heating a zinc-based coated steel sheet to a temperature range from the Ac3 transformation temperature to 1000° C., performing hot pressing work, and performing cooling, in which a surface-cleaning treatment is performed on the zinc-based coated steel sheet before the heating is performed.
- a method for manufacturing a hot-pressed member having an excellent surface appearance including performing cold pressing work on a zinc-based coated steel sheet, heating the zinc-based coated steel sheet to a temperature range from the Ac3 transformation temperature to 1000° C., and cooling the heated steel sheet, in which a surface-cleaning treatment is performed on the zinc-based coated steel sheet before the heating is performed.
- % used when describing the chemical composition of steel or a coating layer always means mass %.
- the hot-pressed member which is manufactured by using the present disclosure can preferably be used for the chassis and body structure members of an automobile.
- FIG. 1 is a diagram illustrating typical examples of the surface appearance of a hot-pressed member, where (a) is a photograph indicating a product having a good surface appearance and (b) is a photograph indicating a product having point-like defects.
- FIG. 2 is a diagram illustrating typical examples of the surface appearance of point-like defects, where (a) is an enlarged photograph of a white defect and (b) is an enlarged photograph of a black defect.
- a zinc-based coated steel sheet having a zinc-based coating layer on one or both sides thereof is used.
- a zinc-based coating layer include, but are not limited to, a galvanizing layer, a galvannealing layer, a hot-dip zinc-aluminum-alloy coating layer, a hot-dip zinc-aluminum-magnesium-alloy coating layer, a zinc electroplating layer, and a zinc-nickel-alloy electroplating layer, and all of the known zinc-based coating layers containing zinc may be used.
- the coating weight on the surface of such a zinc-based coated steel sheet be 10 g/m 2 to 90 g/m 2 per side.
- the coating weight per side (hereinafter, also simply referred to as “coating weight”) is 10 g/m 2 or more, the corrosion resistance does not become insufficient.
- the coating weight is 90 g/m 2 or less, there is no increase in cost.
- the coating weight be 20 g/m 2 to 80 g/m 2 .
- the coating weight of the coating layer should be derived from the amount of decrease in mass at this time.
- the zinc-based coated steel sheet described above be a Zn—Ni-alloy-coated steel sheet having a coating layer on one or both sides thereof, in which the coating layer having a chemical composition containing 10 mass % to 25 mass % of Ni and the balance being Zn and inevitable impurities.
- the Ni content in the coating layer is 10 mass % to 25 mass %
- the structure of the coating layer becomes a ⁇ phase structure, and since this ⁇ phase has a high melting point of 881° C., there is an increase in the effect of inhibiting the generation of point-like defects to a higher level.
- a ⁇ phase has one of the crystal structures of Ni 2 Zn 11 , NiZn 3 , and Ni 5 Zn 21 , and it is possible to identify the structure by using an X-ray diffraction method.
- an underlying coating layer such as a coating layer mainly containing, for example, Ni may be formed under the above-described coating layer.
- a hot-rolled steel sheet or a cold-rolled steel sheet having a chemical composition containing, by mass %, C: 0.15% to 0.50%, Si: 0.05% to 2.00%, Mn: 0.5% to 3.0%, P: 0.10% or less, S: 0.05% or less, Al: 0.10% or less, N: 0.010% or less, and the balance being Fe and inevitable impurities may be used as a base steel sheet for a zinc-based coating layer.
- a hot-rolled steel sheet or a cold-rolled steel sheet having such a chemical composition is used as a base steel sheet, it is possible to obtain a hot-pressed member having a desired high strength of, for example, 980 MPa or more.
- C is a chemical element which increases the strength of steel, and it is necessary that the C content be 0.15% or more in order to control the tensile strength (hereinafter, also referred to as “TS”) of a hot-pressed member to be 980 MPa or more.
- TS tensile strength
- the C content be 0.15% to 0.50%.
- Si is, like C, a chemical element which increases the strength of steel, and it is necessary that the Si content be 0.05% or more in order to control the TS of a hot-pressed member to be 980 MPa or more.
- the Si content is more than 2.00%, there is a significant increase in the amount of a surface defect, which is called red scale, generated when hot rolling is performed, there is an increase in rolling load, and there is a deterioration in the ductility of a hot-rolled steel sheet.
- the Si content is more than 2.00%, there may be a negative effect on coatability when a coating treatment is performed in order to form a coating film containing mainly Zn and Al on the surface of a steel sheet. Therefore, it is preferable that the Si content be 0.05% to 2.00%.
- Mn is a chemical element which is effective for improving hardenability by inhibiting ferrite transformation and which is effective for decreasing a heating temperature before hot pressing is performed, because Mn decreases the Ac 3 transformation temperature. It is necessary that the Mn content be 0.5% or more in order to realize such effects. On the other hand, in the case where the Mn content is more than 3.0%, since Mn is segregated, there is a deterioration in the homogeneity of the properties of a steel sheet as a material and a hot-pressed member. Therefore, it is preferable that the Mn content be 0.5% to 3.0%.
- the P content is more than 0.10%, since P is segregated, there is a deterioration in the homogeneity of the properties of a steel sheet as a material and a hot-pressed member, and there is a significant decrease in toughness. Therefore, it is preferable that the P content be 0.10% or less.
- the S content is more than 0.05%, there is a decrease in the toughness of a hot-pressed member. Therefore, it is preferable that the S content be 0.05% or less.
- the Al content is more than 0.10%, there is a deterioration in the blanking performance and hardenability of a steel sheet as a material. Therefore, it is preferable that the Al content be 0.10% or less.
- the N content is more than 0.010%, since nitrides of AlN are formed when hot rolling is performed or when heating is performed before hot pressing work is performed, there is a deterioration in the blanking performance and hardenability of a steel sheet as a material Therefore, it is preferable that the N content be 0.010% or less.
- At least one selected from Cr: 0.01% to 1.0%, Ti: 0.01% to 0.20%, and B: 0.0005% to 0.0800% and Sb: 0.003% to 0.030% be added separately or at the same time in addition to the chemical composition described above for the reasons described below.
- Cr is a chemical element which is effective for increasing the strength of steel and improving hardenability of steel. It is preferable that the Cr content be 0.01% or more in order to realize such effects. On the other hand, in the case where the Cr content is more than 1.0%, there is a significant increase in cost. Therefore, it is preferable that the upper limit of the Cr content be 1.0%.
- Ti is a chemical element which is effective for increasing the strength of steel and which is effective for increasing toughness by decreasing a crystal grain size.
- Ti is a chemical element which is effective for realizing the effect of improving hardenability through the use of solid solution B by forming nitrides more readily than B, which will be described below. Therefore, it is preferable that the Ti content be 0.01% or more. However, in the case where the Ti content is more than 0.20%, there is a significant increase in rolling load when hot rolling is performed, and there is a decrease in the toughness of a hot-pressed member. Therefore, it is preferable that the upper limit of the Ti content be 0.20%.
- B is a chemical element which is effective for improving hardenability when hot pressing is performed and for increasing toughness after the hot pressing. It is preferable that the B content be 0.0005% or more in order to realize such effects. On the other hand, in the case where the B content is more than 0.0800%, there is a significant increase in rolling load when hot rolling is performed, and, for example, cracking occurs in a steel sheet due to the formation of a martensite phase and a bainite phase after the hot rolling. Therefore, it is preferable that the upper limit of the B content be 0.0800%.
- Sb is effective for inhibiting the formation of a decarburized layer in the surface layer of a steel sheet in a process in which a zinc-based coated steel sheet is subjected to heating followed by hot pressing work and cooling. It is necessary that the Sb content be 0.003% or more in order to realize such an effect. On the other hand, in the case where the Sb content is more than 0.030%, since there is an increase in rolling load, there is a decrease in productivity. Therefore, it is preferable that the Sb content be 0.003% to 0.030%.
- a hot-pressed member is manufactured by using one of the processes in the two embodiments described below as a hot pressing process.
- the two embodiments discussed herein are exemplary embodiments.
- the first embodiment is a method for manufacturing a hot-pressed member and is a hot pressing process called direct process in which a zinc-based coated steel sheet is subjected to heating to a temperature range from the Ac3 transformation temperature to 1000° C. followed by hot pressing work and cooling.
- the heating temperature is lower than the Ac3 transformation temperature, since there is an insufficient degree of quenching of a steel sheet, there may be a case where it is not possible to achieve the desired strength.
- the heating temperature is higher than 1000° C., there is an economic disadvantage from the viewpoint of energy, and it is difficult to manufacture a hot-pressed member having a homogeneous and good surface appearance due to the significant generation of point-like defects.
- cooling after hot pressing work may be performed by using a mold at the same time as hot pressing work, or the cooling may be performed by using a coolant such as water at the same time as hot pressing work or immediately after the hot pressing work.
- the second embodiment is a method for manufacturing a hot-pressed member and is a hot pressing process called indirect process in which a zinc-based coated steel sheet is subjected to cold pressing work followed by heating to a temperature range from the Ac3 transformation temperature to 1000° C. and cooling.
- cold pressing work is first performed before a zinc-based coated steel sheet is heated.
- the cold-pressed member is subjected to heating followed by cooling.
- the heating temperature is set to be in a temperature range from the Ac3 transformation temperature to 1000° C. for the reasons described above.
- Cooling may be performed by using a mold which is used for cooling a member or by using a coolant such as water.
- work may be added by performing hot pressing.
- heating temperature means the maximum end-point temperature of a steel sheet.
- examples of a method for performing the heating described above include heating which utilizes, for example, an electric furnace or a gas furnace, direct-fired heating, electrical heating, high-frequency heating, and induction heating.
- a surface-cleaning treatment is performed on a zinc-based coated steel sheet before the zinc-based coated steel sheet is heated in order to remove stains due to, for example, dirt, dust, and fingerprint which are adhered to the surface of a coating layer.
- This surface-cleaning treatment is an important requirement in the present disclosure.
- point-like defects are generated as illustrated in FIG. 1( b ) .
- a surface-cleaning treatment it is possible to manufacture a product having a good surface appearance as illustrated in FIG. 1( a ) .
- examples of point-like defects include a white defect illustrated in FIG.
- a surface-cleaning treatment is a treatment which removes the origins of point-like defects.
- a surface-cleaning treatment may be performed on a steel sheet in the form of a coiled steel sheet or in the form of a cut steel sheet or a steel sheet blank, which has been cut out of the coiled steel sheet, or on a cold-pressed member after cold pressing work.
- a surface-cleaning treatment be performed on a steel sheet in the form of a steel sheet blank, because this facilitates the treatment with a high level of surface-cleaning effect.
- a method for performing a surface-cleaning treatment includes one in which the surface of a steel sheet is wiped with waste cloth, one in which the surface of a steel sheet is brushed by using, for example, a nylon brush, one in which the surface of a steel sheet is brushed after a liquid such as a wash oil, which has no negative effect on a steel sheet, has been applied to the surface, and one in which alkaline degreasing or solvent degreasing is performed.
- a method in which a liquid is in contact with the surface of a steel sheet such as a combined method of wash-oil application and brushing, an alkaline degreasing method, or a solvent degreasing method has a higher cleaning effect than a physical method such as one in which wiping with waste cloth or brushing is performed, it is preferable that a method in which a liquid be in contact with the surface of a steel sheet be performed to clean the surface of a steel sheet completely.
- alkaline degreasing is performed as a surface-cleaning treatment by using an alkaline degreasing liquid having a pH of 12.5 or more
- the pH of the alkaline degreasing liquid is set to be less than 12.5.
- the process of a surface-cleaning treatment have a low cost.
- apparatuses for cold pressing work has an apparatus for performing the combination of wash-oil application and brushing, such equipment can preferably be used for hot pressing work, because it is possible to perform a treatment at low cost with a high cleaning effect by using such equipment.
- This cold-rolled steel sheet was coated with one of a galvanizing layer, a hot-dip Zn—Al-alloy coating layer (Al content: 55 mass %), a galvannealing layer (Fe content: 10 mass %), a Zn electroplating layer, and a Zn—Ni-alloy electroplating layer (Ni content: 12 mass %) and cut into a sample having a size of 200 mm ⁇ 300 mm.
- a surface-cleaning treatment was performed by using one of A: a wiping method with waste cloth, B: a brushing method, C: a combined method of wash-oil application and brushing, D: an alkaline degreasing method (pH: 12.0), and E: a solvent degreasing method.
- a surface-cleaning treatment was performed by using one of A: a wiping method with waste cloth, B: a brushing method, C: a combined method of wash-oil application and brushing, D: an alkaline degreasing method (pH: 12.0), and E: a solvent degreasing method.
- F strong alkaline degreasing (pH: 13.0) and samples which had not been subjected to a surface-cleaning treatment were also prepared.
- Wiping with waste cloth was performed by using waste cloth (Cleaning White Stockinet Waste (Cotton) produced by Nihon Waste Co., Ltd.) and by wiping the surface of a sample twice with a reciprocating movement of a hand.
- Brushing was performed by using a nylon-fiber plant brush (SK-type Straight Brush produced by Showa Kogyo Co., Ltd.) and by brushing the surface of a sample twice with a reciprocating movement of a hand.
- SK-type Straight Brush produced by Showa Kogyo Co., Ltd.
- wash-oil application and brushing were performed by performing brushing as described above after having applied a wash rust-prevention oil (PRETON R352L produced by Sugimura Chemical Industrial Co., Ltd.) to the surface of a sample so that the amount of oil applied was 2.0 g/m 2 .
- a wash rust-prevention oil PRETON R352L produced by Sugimura Chemical Industrial Co., Ltd.
- Alkaline degreasing was performed by spraying a sample with an alkaline degreasing liquid (CL-N364S, 20 g/L, 60° C., produced by Nihon Parkerizing Co., LTD.) for 10 seconds, and thereafter performing water washing followed by drying.
- an alkaline degreasing liquid (CL-N364S, 20 g/L, 60° C., produced by Nihon Parkerizing Co., LTD.) for 10 seconds, and thereafter performing water washing followed by drying.
- the pH of the alkaline degreasing liquid was 12.0.
- Solvent degreasing was performed by immersing a sample in a combined solvent of toluene and ethanol having a mixture ratio of 1:1, and thereafter performing ultrasonic cleaning for one minute and drying.
- Strong alkaline degreasing which was performed as a comparative example, was performed by immersing a sample in a strong alkaline degreasing liquid (NaOH aqueous solution, pH: controlled to be 13.0, 50° C.) for seconds, and thereafter performing water washing followed by drying.
- a strong alkaline degreasing liquid NaOH aqueous solution, pH: controlled to be 13.0, 50° C.
- the sample was heated in an electric furnace at a temperature of 950° C. so that duration of the sample in the electric furnace was 8 minutes, the sample was taken out of the furnace immediately after completion of heating, and then held in a flat, mold made of Al in order to perform a rapid cooling treatment (cooling rate: 50° C./s).
- Ten samples were each prepared under the same condition in order to increase the judgment accuracy of surface appearance. After having performed a visual test regarding the state of point-like defects of the samples, surface appearance was judged on the basis of the judgment criteria below, and the case of ⁇ or ⁇ was judged as satisfactory.
- the effect of the present disclosure was evaluated on the basis of the evaluation of the surface appearance after having heated and cooled a flat sheet as described above without performing practical press forming which utilized a direct process or an indirect process
- the results of the present evaluation are the same as those of the evaluation of the surface appearance after having performed practical press forming which utilizes the above-mentioned two processes, because the surface appearance after having performed heating and cooling depends on whether or not stain components exist on the surface of the sample and on the effect of removing the stain components.
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Abstract
Description
- The present disclosure relates to a method for manufacturing a hot-pressed member which can preferably be used for, for example, chassis and body structure members of an automobile.
- To date, for example, chassis and body structure members of an automobile have usually been manufactured by performing press working on steel sheets having a specified strength. Nowadays, since there is a strong demand for the weight reduction of an automobile body from the viewpoint of global environment conservation, efforts are being made to reduce the thickness of a steel sheet which is used for an automobile body by increasing the strength of the steel sheet. However, an increase in the strength of steel sheets causes a deterioration in press workability, and therefore there is an increase in the number of cases where it is difficult to form a steel sheet into desired shapes of the members.
- In view of the situation described above, Patent Literature 1 proposes a working technique called hot pressing which makes it possible to realize an improvement in workability and an increase in strength at the same time by performing working and rapid cooling at the same time on a heated steel sheet by using a mold which is composed of a die and a punch. However, the case of this hot pressing, since a steel sheet is heated to a high temperature of about 950° C. before hot pressing is performed, scale (iron oxide) is generated on the surface of the steel sheet, and the flaking of the scale occurs when hot pressing is performed, which results in a problem in that a mold is damaged or the surface of a member is damaged after the hot pressing. Also, scale which remained on the surface of a member causes a deterioration in surface appearance and paint adhesiveness. Therefore, scale which is present on the surface of a member is usually removed by performing a treatment such as pickling or shot blasting. However, such a treatment makes a manufacturing process complex, and thus there is a decrease in productivity.
- Moreover, for example, chassis and body structure members of an automobile are also required to have excellent corrosion resistance. However, since a hot-pressed member, which is manufactured by using the process described above, is not provided with an anti-corrosion film such as a coating layer, the member is very poor in terms of corrosion resistance.
- Therefore, a hot-pressing technique is desired with which the generation of scale can be inhibited when heating is performed before hot pressing and with which the corrosion resistance of a hot-pressed member can be improved, and thus a steel sheet to be hot-pressed whose surface is coated with a film such as a coating layer and a method for hot pressing which utilizes the steel sheet have been proposed.
- For example, Patent Literature 2 discloses a method for manufacturing a hot-pressed member excellent in terms of corrosion resistance whose surface is coated with a Zn—Fe-based compound or a Zn—Fe—Al-based compound by performing hot pressing on a steel sheet, which is coated with Zn or a Zn-based alloy.
- In addition, Patent Literature 3 discloses a hot-pressed member excellent in terms of scale resistance, paint adhesiveness, after-painting corrosion resistance, and hydrogen entry resistance which is manufactured by forming a Ni diffusion region, a layer of an intermetallic compound, which is equivalent to the γ phase of a Zn—Ni alloy, and a ZnO layer in the surface layer of a steel sheet.
- Moreover, Patent Literature 4 discloses a steel sheet to be hot-pressed which is manufactured by forming a ZnO layer, which inhibits the vaporization of Zn, in the surface layer of a Zn-based coating layer in advance, and indicates that it is possible to obtain a hot-pressed product having good surface appearance, excellent paint adhesiveness, and excellent after-painting corrosion resistance by using the steel sheet.
- PTL 1: UK Patent No. GB1490535
- PTL 2: Japanese Patent No. 3663145
- PTL 3: Japanese Patent No. 4849186
- PTL 4: Japanese Patent No. 3582511
- As disclosed in the conventional techniques described above, using a zinc-based coated steel sheet as a steel sheet to be hot-pressed is effective for improving corrosion resistance. However, since the melting point of zinc is 419° C. and the boiling point of zinc is 907° C., that is, since both are low, the melting of zinc in the coating layer and the vaporization of zinc from the coating layer occur in a heating process before hot pressing, which makes it difficult to stably manufacture a hot-pressed member having a homogeneous and good surface appearance.
- For example, in the case of a hot-pressed member which is manufactured by using the method described in Patent Literature 2, since a zinc-coated steel sheet or a zinc-aluminum-coated steel sheet, whose coating layer has a low melting point, is used, the melting of the coating layer or the vaporization of zinc which occurs in a heating process before hot pressing is significant. As a result, a hot-pressed member, which is finally obtained, has, for example, a spotty inhomogeneous surface appearance or many white or black point-like defects. Therefore, it is difficult to obtain a hot-pressed member having a homogeneous and good surface appearance. Here, since not only a deterioration in surface appearance but also a deterioration in paint adhesiveness occur in a portion in which point-like defects exist, there is a strong demand for a technique for preventing point-like defects. However, an effective technique has not been proposed.
- In the case of a hot-pressed member described in Patent Literature 3 which is manufactured by using a steel sheet coated with a Zn—Ni-alloy coating layer, which has a melting point higher than that of Zn, there is an improvement in the surface appearance of a hot-pressed member compared with the case where a zinc-coated steel sheet or a zinc-aluminum-coated steel sheet is used. However, it is not possible to completely prevent the generation of local point-like defects.
- In the case where a steel sheet to be hot-pressed described in Patent Literature 4 is used, there is an improvement in the surface appearance of a hot-pressed member to some extent through the effect of a ZnO layer which is formed in the surface layer of the steel sheet. However, there is still a problem in that local point-like defects are generated in a portion in which the result of a treatment for forming a ZnO layer is inhomogeneous. In addition, there is a problem of a significant increase in cost when a treatment for forming a ZnO layer is performed, because it is necessary to use a method which involves, for example, an oxidizing treatment through the use of heat, a contact treatment with a solution, an electrolysis treatment in an aqueous solution, and a treatment of coating and drying a solution.
- The present disclosure has been completed in order to solve the problems of the conventional techniques described above, and an object of the present disclosure is to provide a method for manufacturing a hot-pressed member excellent in terms of surface appearance with which it is possible to stably manufacture a hot-pressed member having a homogeneous and good surface appearance without causing a significant increase in cost.
- The present inventors, in order to solve the problems described above, diligently conducted investigations regarding a method for manufacturing a hot-pressed member excellent in terms of surface appearance. First, investigations regarding a state in which point-like defects are generated on the surface of a hot-pressed member were conducted. As a result, it was found that the position or number of point-like defects is not necessarily the same even if the same kind of zinc-based coated steel sheet is heated under the same condition. Also, it was found that it is not possible to completely prevent point-like defects even with a Zn—Ni-alloy-coated steel sheet, although a steel sheet coated with a Zn—Ni-alloy coating layer, which has a higher melting point than that of zinc-based coated steel sheet, can be used as a steel sheet to be hot-pressed more advantageously than a zinc-based coated steel sheet such as a galvanized steel sheet or a galvannealed steel sheet, which has a coating layer having a comparatively low melting point, from the viewpoint of inhibiting point-like defects from occurring.
- From such facts, on the basis of the hypothesis that the generation of point-like defects depends not only on the kind of a coating layer and heating conditions but also on other factors such as a stain on the surface, verification experiments were conducted in which a zinc-based coated steel sheet was heated after the surface of the steel sheet had been stained or cleaned. As a result, it was found that point-like defects, which are generated on the surface of a hot-pressed member, are caused by stains due to, for example, dirt, dust, and fingerprint which are adhered to the surface of a coating layer. That is, it was found that there is a local increase in temperature due to extraneous matter derived from such stain materials being burned in a heating process before hot pressing work, which results in the vaporization of zinc being promoted due to the breakage of a ZnO layer with which the surface of the zinc-based coating layer has been covered, and which results in scale being generated in such a portion. In addition, it was further found that it is possible to significantly inhibit the generation of point-like defects by performing a surface-cleaning treatment in order to remove such stain materials before a heating process. Moreover, it was found that the effect of inhibiting point-like defects through the use of a surface-cleaning treatment before heating is realized not only in a process in which a zinc-based coated steel sheet is subjected to hot pressing work and cooling after having been heated but also in a process in which a zinc-based coated steel sheet is heated and cooled after having been subjected to cold pressing work.
- The method for manufacturing a hot-pressed member according to the present disclosure has been completed on the basis of such findings.
- [1] A method for manufacturing a hot-pressed member having an excellent surface appearance, the method including heating a zinc-based coated steel sheet to a temperature range from the Ac3 transformation temperature to 1000° C., performing hot pressing work, and performing cooling, in which a surface-cleaning treatment is performed on the zinc-based coated steel sheet before the heating is performed.
- [2] A method for manufacturing a hot-pressed member having an excellent surface appearance, the method including performing cold pressing work on a zinc-based coated steel sheet, heating the zinc-based coated steel sheet to a temperature range from the Ac3 transformation temperature to 1000° C., and cooling the heated steel sheet, in which a surface-cleaning treatment is performed on the zinc-based coated steel sheet before the heating is performed.
- [3] The method for manufacturing a hot-pressed member according to item [1] or [2], in which the zinc-based coated steel sheet is a Zn—Ni-alloy-coated steel sheet having a coating layer on one or both sides of the Zn—Ni-alloy-coated steel sheet, and the coating layer has a chemical composition containing 10 mass % to 25 mass % of Ni and the balance being Zn and inevitable impurities and a coating weight per side of 10 g/m2 to 90 g/m2.
- Here, in the present description, % used when describing the chemical composition of steel or a coating layer always means mass %.
- According to the present disclosure, it is possible to stably manufacture a hot-pressed member having a homogeneous and good surface appearance without causing a significant increase in cost. The hot-pressed member which is manufactured by using the present disclosure can preferably be used for the chassis and body structure members of an automobile.
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FIG. 1 is a diagram illustrating typical examples of the surface appearance of a hot-pressed member, where (a) is a photograph indicating a product having a good surface appearance and (b) is a photograph indicating a product having point-like defects. -
FIG. 2 is a diagram illustrating typical examples of the surface appearance of point-like defects, where (a) is an enlarged photograph of a white defect and (b) is an enlarged photograph of a black defect. - 1) Zinc-Based Coated Steel Sheet
- In the method for manufacturing a hot-pressed member according to the present disclosure, a zinc-based coated steel sheet having a zinc-based coating layer on one or both sides thereof is used. Examples of a zinc-based coating layer include, but are not limited to, a galvanizing layer, a galvannealing layer, a hot-dip zinc-aluminum-alloy coating layer, a hot-dip zinc-aluminum-magnesium-alloy coating layer, a zinc electroplating layer, and a zinc-nickel-alloy electroplating layer, and all of the known zinc-based coating layers containing zinc may be used.
- It is preferable that the coating weight on the surface of such a zinc-based coated steel sheet be 10 g/m2 to 90 g/m2 per side. In the case where the coating weight per side (hereinafter, also simply referred to as “coating weight”) is 10 g/m2 or more, the corrosion resistance does not become insufficient. On the other hand, in the case where the coating weight is 90 g/m2 or less, there is no increase in cost. It is more preferable that the coating weight be 20 g/m2 to 80 g/m2. Here, it is possible to determine coating weight by using a wet analysis method. Specifically, for example, by dissolving the whole coating layer of a test piece whose coated area is known in an aqueous solution in which 1 g/L of hexamethylenetetramine is added as an inhibitor to a 6-mass %-hydrochloric acid aqueous solution, the coating weight of the coating layer should be derived from the amount of decrease in mass at this time.
- It is preferable that the zinc-based coated steel sheet described above be a Zn—Ni-alloy-coated steel sheet having a coating layer on one or both sides thereof, in which the coating layer having a chemical composition containing 10 mass % to 25 mass % of Ni and the balance being Zn and inevitable impurities. In. the case where the Ni content in the coating layer is 10 mass % to 25 mass %, since the structure of the coating layer becomes a γ phase structure, and since this γ phase has a high melting point of 881° C., there is an increase in the effect of inhibiting the generation of point-like defects to a higher level. Here a γ phase has one of the crystal structures of Ni2Zn11, NiZn3, and Ni5Zn21, and it is possible to identify the structure by using an X-ray diffraction method. Here, an underlying coating layer such as a coating layer mainly containing, for example, Ni may be formed under the above-described coating layer.
- 2) Base Steel Sheet
- In order to obtain the hot-pressed member according to the present disclosure, a hot-rolled steel sheet or a cold-rolled steel sheet having a chemical composition containing, by mass %, C: 0.15% to 0.50%, Si: 0.05% to 2.00%, Mn: 0.5% to 3.0%, P: 0.10% or less, S: 0.05% or less, Al: 0.10% or less, N: 0.010% or less, and the balance being Fe and inevitable impurities may be used as a base steel sheet for a zinc-based coating layer. In the case where a hot-rolled steel sheet or a cold-rolled steel sheet having such a chemical composition is used as a base steel sheet, it is possible to obtain a hot-pressed member having a desired high strength of, for example, 980 MPa or more.
- The reasons for the limitations on the constituent chemical elements will be described hereafter.
- C: 0.15% to 0.50%
- C is a chemical element which increases the strength of steel, and it is necessary that the C content be 0.15% or more in order to control the tensile strength (hereinafter, also referred to as “TS”) of a hot-pressed member to be 980 MPa or more. On the other hand, in the case where the C content is more than 0.50%, there is a significant deterioration in the blanking performance of a steel sheet as a material. Therefore, it is preferable that the C content be 0.15% to 0.50%.
- Si: 0.05% to 2.00%
- Si is, like C, a chemical element which increases the strength of steel, and it is necessary that the Si content be 0.05% or more in order to control the TS of a hot-pressed member to be 980 MPa or more. On the other hand, in the case where the Si content is more than 2.00%, there is a significant increase in the amount of a surface defect, which is called red scale, generated when hot rolling is performed, there is an increase in rolling load, and there is a deterioration in the ductility of a hot-rolled steel sheet. Moreover, in the case where the Si content is more than 2.00%, there may be a negative effect on coatability when a coating treatment is performed in order to form a coating film containing mainly Zn and Al on the surface of a steel sheet. Therefore, it is preferable that the Si content be 0.05% to 2.00%.
- Mn: 0.5% to 3.0%
- Mn is a chemical element which is effective for improving hardenability by inhibiting ferrite transformation and which is effective for decreasing a heating temperature before hot pressing is performed, because Mn decreases the Ac3 transformation temperature. It is necessary that the Mn content be 0.5% or more in order to realize such effects. On the other hand, in the case where the Mn content is more than 3.0%, since Mn is segregated, there is a deterioration in the homogeneity of the properties of a steel sheet as a material and a hot-pressed member. Therefore, it is preferable that the Mn content be 0.5% to 3.0%.
- P: 0.10% or Less
- In the case where the P content is more than 0.10%, since P is segregated, there is a deterioration in the homogeneity of the properties of a steel sheet as a material and a hot-pressed member, and there is a significant decrease in toughness. Therefore, it is preferable that the P content be 0.10% or less.
- S: 0.05% or Less
- In the case where the S content is more than 0.05%, there is a decrease in the toughness of a hot-pressed member. Therefore, it is preferable that the S content be 0.05% or less.
- Al: 0.10% or Less
- In the case where the Al content is more than 0.10%, there is a deterioration in the blanking performance and hardenability of a steel sheet as a material. Therefore, it is preferable that the Al content be 0.10% or less.
- N: 0.010% or Less
- In the case where the N content is more than 0.010%, since nitrides of AlN are formed when hot rolling is performed or when heating is performed before hot pressing work is performed, there is a deterioration in the blanking performance and hardenability of a steel sheet as a material Therefore, it is preferable that the N content be 0.010% or less.
- The remainder is and inevitable impurities. Moreover, it is preferable that at least one selected from Cr: 0.01% to 1.0%, Ti: 0.01% to 0.20%, and B: 0.0005% to 0.0800% and Sb: 0.003% to 0.030% be added separately or at the same time in addition to the chemical composition described above for the reasons described below.
- Cr: 0.01% to 1.0%
- Cr is a chemical element which is effective for increasing the strength of steel and improving hardenability of steel. It is preferable that the Cr content be 0.01% or more in order to realize such effects. On the other hand, in the case where the Cr content is more than 1.0%, there is a significant increase in cost. Therefore, it is preferable that the upper limit of the Cr content be 1.0%.
- Ti: 0.01% to 0.20%
- Ti is a chemical element which is effective for increasing the strength of steel and which is effective for increasing toughness by decreasing a crystal grain size. In addition, Ti is a chemical element which is effective for realizing the effect of improving hardenability through the use of solid solution B by forming nitrides more readily than B, which will be described below. Therefore, it is preferable that the Ti content be 0.01% or more. However, in the case where the Ti content is more than 0.20%, there is a significant increase in rolling load when hot rolling is performed, and there is a decrease in the toughness of a hot-pressed member. Therefore, it is preferable that the upper limit of the Ti content be 0.20%.
- B: 0.0005% to 0.0800%
- B is a chemical element which is effective for improving hardenability when hot pressing is performed and for increasing toughness after the hot pressing. It is preferable that the B content be 0.0005% or more in order to realize such effects. On the other hand, in the case where the B content is more than 0.0800%, there is a significant increase in rolling load when hot rolling is performed, and, for example, cracking occurs in a steel sheet due to the formation of a martensite phase and a bainite phase after the hot rolling. Therefore, it is preferable that the upper limit of the B content be 0.0800%.
- Sb: 0.003% to 0.030%
- Sb is effective for inhibiting the formation of a decarburized layer in the surface layer of a steel sheet in a process in which a zinc-based coated steel sheet is subjected to heating followed by hot pressing work and cooling. It is necessary that the Sb content be 0.003% or more in order to realize such an effect. On the other hand, in the case where the Sb content is more than 0.030%, since there is an increase in rolling load, there is a decrease in productivity. Therefore, it is preferable that the Sb content be 0.003% to 0.030%.
- 3) Hot Pressing Process
- In the method for manufacturing a hot-pressed member according to the present disclosure, a hot-pressed member is manufactured by using one of the processes in the two embodiments described below as a hot pressing process. The two embodiments discussed herein are exemplary embodiments.
- The first embodiment is a method for manufacturing a hot-pressed member and is a hot pressing process called direct process in which a zinc-based coated steel sheet is subjected to heating to a temperature range from the Ac3 transformation temperature to 1000° C. followed by hot pressing work and cooling. In the case where the heating temperature is lower than the Ac3 transformation temperature, since there is an insufficient degree of quenching of a steel sheet, there may be a case where it is not possible to achieve the desired strength. In addition, in the case where the heating temperature is higher than 1000° C., there is an economic disadvantage from the viewpoint of energy, and it is difficult to manufacture a hot-pressed member having a homogeneous and good surface appearance due to the significant generation of point-like defects. In addition, cooling after hot pressing work may be performed by using a mold at the same time as hot pressing work, or the cooling may be performed by using a coolant such as water at the same time as hot pressing work or immediately after the hot pressing work.
- The second embodiment is a method for manufacturing a hot-pressed member and is a hot pressing process called indirect process in which a zinc-based coated steel sheet is subjected to cold pressing work followed by heating to a temperature range from the Ac3 transformation temperature to 1000° C. and cooling. In this process, cold pressing work is first performed before a zinc-based coated steel sheet is heated. Subsequently, the cold-pressed member is subjected to heating followed by cooling. The heating temperature is set to be in a temperature range from the Ac3 transformation temperature to 1000° C. for the reasons described above. Cooling may be performed by using a mold which is used for cooling a member or by using a coolant such as water. In addition, when cooling is performed by using a mold, work may be added by performing hot pressing.
- Here, the term “heating temperature” means the maximum end-point temperature of a steel sheet. In addition, examples of a method for performing the heating described above include heating which utilizes, for example, an electric furnace or a gas furnace, direct-fired heating, electrical heating, high-frequency heating, and induction heating.
- 4) Surface-Cleaning Treatment
- In the method for manufacturing a hot-pressed member according to the present disclosure, a surface-cleaning treatment is performed on a zinc-based coated steel sheet before the zinc-based coated steel sheet is heated in order to remove stains due to, for example, dirt, dust, and fingerprint which are adhered to the surface of a coating layer. This surface-cleaning treatment is an important requirement in the present disclosure. In the case where this surface-cleaning treatment is not performed, point-like defects are generated as illustrated in
FIG. 1(b) . On the other hand, in the case where a surface-cleaning treatment is performed, it is possible to manufacture a product having a good surface appearance as illustrated inFIG. 1(a) . Here, examples of point-like defects include a white defect illustrated inFIG. 2(a) , which is a mark of intense vaporization of zinc left at the position of the breakage of a ZnO layer, with which the surface of a zinc-based coating layer has been covered, and a black defect illustrated inFIG. 2(b) , which is generated as a result of scale being generated through the progress of the oxidation of a base steel sheet at the position of a white defect. Since, both of the point-like defects deteriorate surface appearance and paint adhesiveness, it is necessary to inhibit point-like defects as much as possible by performing a surface-cleaning treatment. As described above, a surface-cleaning treatment according to the present disclosure is a treatment which removes the origins of point-like defects. - It is necessary to perform a surface-cleaning treatment before a heating process. Therefore, in the case of the first embodiment described above (in which a zinc-based coated steel sheet is subjected to heating to a temperature range from the Ac3 transformation temperature to 1000° C. followed by hot pressing work), it is necessary to perform a surface-cleaning treatment on a steel sheet in the form of a coiled steel sheet or in the form of a cut steel sheet or a steel sheet blank, which has been cut out of the coiled steel sheet. In addition, in the case of the second embodiment described above (in which a zinc-based coated steel sheet is subjected to cold pressing work followed by heating to a temperature range from the Ac3 transformation temperature to 1000° C.), a surface-cleaning treatment may be performed on a steel sheet in the form of a coiled steel sheet or in the form of a cut steel sheet or a steel sheet blank, which has been cut out of the coiled steel sheet, or on a cold-pressed member after cold pressing work. Here, in any one of the first embodiment and the second embodiment, it is preferable at the period of time from the end of a surface cleaning treatment to the beginning of heating be as short as possible. In addition, it is preferable that a surface-cleaning treatment be performed on a steel sheet in the form of a steel sheet blank, because this facilitates the treatment with a high level of surface-cleaning effect.
- There is no particular limitation on the method used for performing a surface-cleaning treatment as long as it is possible to remove stains due to, for example, dirt, dust, and fingerprint which are adhered to the surface of a coating layer. Examples of a method for performing a surface-cleaning treatment include one in which the surface of a steel sheet is wiped with waste cloth, one in which the surface of a steel sheet is brushed by using, for example, a nylon brush, one in which the surface of a steel sheet is brushed after a liquid such as a wash oil, which has no negative effect on a steel sheet, has been applied to the surface, and one in which alkaline degreasing or solvent degreasing is performed. Since a method in which a liquid is in contact with the surface of a steel sheet such as a combined method of wash-oil application and brushing, an alkaline degreasing method, or a solvent degreasing method has a higher cleaning effect than a physical method such as one in which wiping with waste cloth or brushing is performed, it is preferable that a method in which a liquid be in contact with the surface of a steel sheet be performed to clean the surface of a steel sheet completely. However, in the case where alkaline degreasing is performed as a surface-cleaning treatment by using an alkaline degreasing liquid having a pH of 12.5 or more, since there is an excessive effect of dissolving a zinc-based coating layer, the generation of point-like defects is conversely promoted due to inhomogeneous dissolution, and there is a deterioration in corrosion resistance due to a decrease in coating weight. Therefore, in the case where alkaline degreasing is performed as a surface-cleaning treatment by using an alkaline degreasing liquid, the pH of the alkaline degreasing liquid is set to be less than 12.5. Moreover, it is preferable that the process of a surface-cleaning treatment have a low cost. In the case where apparatuses for cold pressing work has an apparatus for performing the combination of wash-oil application and brushing, such equipment can preferably be used for hot pressing work, because it is possible to perform a treatment at low cost with a high cleaning effect by using such equipment.
- A cold-rolled steel sheet having a chemical composition containing, by mass %, C: 0.23%, Si: 0.25%, Mn: 1.2%, P: 0.01%, S: 0.01%, Al: 0.03%, N: 0.005%, Cr: 0.2%, Ti: 0.02%, B: 0.0022%, Sb: 0.008%, and the balance being Fe and inevitable impurities, an Ac3 transformation temperature of 820° C., and a thickness of 1.6 mm was used as a base steel sheet. The surface of this cold-rolled steel sheet was coated with one of a galvanizing layer, a hot-dip Zn—Al-alloy coating layer (Al content: 55 mass %), a galvannealing layer (Fe content: 10 mass %), a Zn electroplating layer, and a Zn—Ni-alloy electroplating layer (Ni content: 12 mass %) and cut into a sample having a size of 200 mm×300 mm.
- The sample obtained as described above was subjected to a surface-cleaning treatment. A surface-cleaning treatment was performed by using one of A: a wiping method with waste cloth, B: a brushing method, C: a combined method of wash-oil application and brushing, D: an alkaline degreasing method (pH: 12.0), and E: a solvent degreasing method. As comparative examples, samples which had been subjected to F: strong alkaline degreasing (pH: 13.0) and samples which had not been subjected to a surface-cleaning treatment were also prepared.
- Wiping with waste cloth was performed by using waste cloth (Cleaning White Stockinet Waste (Cotton) produced by Nihon Waste Co., Ltd.) and by wiping the surface of a sample twice with a reciprocating movement of a hand.
- Brushing was performed by using a nylon-fiber plant brush (SK-type Straight Brush produced by Showa Kogyo Co., Ltd.) and by brushing the surface of a sample twice with a reciprocating movement of a hand.
- The combination of wash-oil application and brushing was performed by performing brushing as described above after having applied a wash rust-prevention oil (PRETON R352L produced by Sugimura Chemical Industrial Co., Ltd.) to the surface of a sample so that the amount of oil applied was 2.0 g/m2.
- Alkaline degreasing was performed by spraying a sample with an alkaline degreasing liquid (CL-N364S, 20 g/L, 60° C., produced by Nihon Parkerizing Co., LTD.) for 10 seconds, and thereafter performing water washing followed by drying. Here, at this time, the pH of the alkaline degreasing liquid was 12.0.
- Solvent degreasing was performed by immersing a sample in a combined solvent of toluene and ethanol having a mixture ratio of 1:1, and thereafter performing ultrasonic cleaning for one minute and drying.
- Strong alkaline degreasing, which was performed as a comparative example, was performed by immersing a sample in a strong alkaline degreasing liquid (NaOH aqueous solution, pH: controlled to be 13.0, 50° C.) for seconds, and thereafter performing water washing followed by drying.
- Subsequently, the sample was heated in an electric furnace at a temperature of 950° C. so that duration of the sample in the electric furnace was 8 minutes, the sample was taken out of the furnace immediately after completion of heating, and then held in a flat, mold made of Al in order to perform a rapid cooling treatment (cooling rate: 50° C./s).
- The surface appearance of the samples (zinc-based coated steel sheets) obtained as described above was evaluated by using the following method.
- Ten samples were each prepared under the same condition in order to increase the judgment accuracy of surface appearance. After having performed a visual test regarding the state of point-like defects of the samples, surface appearance was judged on the basis of the judgment criteria below, and the case of ⊙ or ◯ was judged as satisfactory. Here, in the examples of the present disclosure, although the effect of the present disclosure was evaluated on the basis of the evaluation of the surface appearance after having heated and cooled a flat sheet as described above without performing practical press forming which utilized a direct process or an indirect process, the results of the present evaluation are the same as those of the evaluation of the surface appearance after having performed practical press forming which utilizes the above-mentioned two processes, because the surface appearance after having performed heating and cooling depends on whether or not stain components exist on the surface of the sample and on the effect of removing the stain components.
-
- ◯: 8 to 9 out of the 10 samples had no point-like defect
- Δ: 5 to 7 out of the 10 samples had no point-like defect
- ×: 0 to 4 out of the 10 samples had no point-like defect
- The results of the evaluation of surface appearance are given in Table 1 in combination with the manufacturing conditions.
-
TABLE 1 Coating Layer Coating Steel Weight per Sheet Side Surface-cleaning Treatment Surface No. Type * (g/m2) Code Treatment Method Appearance Note 1 GI 60 A Wiping with Waste Cloth ∘ Example 2 GL 80 A Wiping with Waste Cloth ∘ Example 3 GA 20 A Wiping with Waste Cloth ∘ Example 4 GA 45 A Wiping with Waste Cloth ∘ Example 5 GA 90 A Wiping with Waste Cloth ∘ Example 6 EG 40 A Wiping with Waste Cloth ∘ Example 7 ZN 10 A Wiping with Waste Cloth Example 8 ZN 60 A Wiping with Waste Cloth Example 9 ZN 90 A Wiping with Waste Cloth Example 10 GI 60 B Brushing ∘ Example 11 GL 80 B Brushing ∘ Example 12 GA 20 B Brushing ∘ Example 13 GA 45 B Brushing ∘ Example 14 GA 90 B Brushing ∘ Example 15 EG 40 B Brushing ∘ Example 16 ZN 10 B Brushing Example 17 ZN 60 B Brushing Example 18 ZN 90 B Brushing Example 19 GI 60 C Wash-oil Application + Brushing Example 20 GL 80 C Wash-oil Application + Brushing Example 21 GA 20 C Wash-oil Application + Brushing Example 22 GA 45 C Wash-oil Application + Brushing Example 23 GA 90 C Wash-oil Application + Brushing Example 24 EG 40 C Wash-oil Application + Brushing Example 25 ZN 10 C Wash-oil Application + Brushing Example 26 ZN 60 C Wash-oil Application + Brushing Example 27 ZN 90 C Wash-oil Application + Brushing Example 28 GI 60 D Alkaline Degreasing Example 29 GL 80 D Alkaline Degreasing Example 30 GA 20 D Alkaline Degreasing Example 31 GA 45 D Alkaline Degreasing Example 32 GA 90 D Alkaline Degreasing Example 33 EG 40 D Alkaline Degreasing Example 34 ZN 10 D Alkaline Degreasing Example 35 ZN 60 D Alkaline Degreasing Example 36 ZN 90 D Alkaline Degreasing Example 37 GI 60 E Solvent Degreasing Example 38 GL 80 E Solvent Degreasing Example 39 GA 20 E Solvent Degreasing Example 40 GA 45 E Solvent Degreasing Example 41 GA 90 E Solvent Degreasing Example 42 EG 40 E Solvent Degreasing Example 43 ZN 10 E Solvent Degreasing Example 44 ZN 60 E Solvent Degreasing Example 45 ZN 90 E Solvent Degreasing Example 46 GI 60 F Strong Alkaline Degreasing x Comparative Example 47 GL 80 F Strong Alkaline Degreasing x Comparative Example 48 GA 20 F Strong Alkaline Degreasing x Comparative Example 49 GA 45 F Strong Alkaline Degreasing x Comparative Example 50 GA 90 F Strong Alkaline Degreasing x Comparative Example 51 EG 40 F Strong Alkaline Degreasing x Comparative Example 52 ZN 10 F Strong Alkaline Degreasing Δ Comparative Example 53 ZN 60 F Strong Alkaline Degreasing Δ Comparative Example 54 ZN 90 F Strong Alkaline Degreasing Δ Comparative Example 55 GI 60 — No Treatment x Comparative Example 56 GL 80 — No Treatment x Comparative Example 57 GA 20 — No Treatment x Comparative Example 58 GA 45 — No Treatment x Comparative Example 59 GA 90 — No Treatment x Comparative Example 60 EG 40 — No Treatment x Comparative Example 61 ZN 10 — No Treatment Δ Comparative Example 62 ZN 60 — No Treatment Δ Comparative Example 63 ZN 90 — No Treatment Δ Comparative Example * GI: galvanizing layer GL: hot-dip Zn-Al-alloy coating layer (Al content: 55 mass %) GA: galvannealing layer (Fe content: 10 mass %) EG: Zn electroplating layer ZN: Zn-Ni-alloy electroplating layer (Ni content: 12 mass %) - It is clarified that all the zinc-based coated steel sheets (examples of the present disclosure), which were manufactured by performing a surface-cleaning treatment in the manufacturing method according to the present disclosure, were excellent in terms of surface appearance. In particular, it is clarified that the surface appearance was absolutely excellent in the case where a Zn—Ni-alloy-electroplated steel sheet was used. On the other hand, the zinc-based coated steel sheet (comparative example), which was subjected to degreasing with a strong alkali having a pH of 12.5 or more, and the zinc-based coated steel sheet (comparative example), which was not subjected to a surface-cleaning treatment, were poor in terms of surface appearance.
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CN114029699B (en) * | 2021-10-22 | 2022-08-30 | 广东中辉绿建移动房屋科技有限公司 | Preparation method of galvanized roof and integrated house roof |
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Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2159292A1 (en) * | 2007-06-15 | 2010-03-03 | Sumitomo Metal Industries, Ltd. | Process for manufacturing shaped article |
US20120164472A1 (en) * | 2009-08-25 | 2012-06-28 | Thyssenkrupp Steel Europe Ag | Method of Producing a Steel Component Provided with a Metallic Coating Giving Protection Against Corrosion, and a Steel Component |
US20130252017A1 (en) * | 2010-11-25 | 2013-09-26 | Jfe Steel Corporation | Steel sheet for hot pressing and method for manufacturing hot-pressed member using the same |
JP2015104753A (en) * | 2013-12-02 | 2015-06-08 | 新日鐵住金株式会社 | Manufacturing method of hot stamp steel material and hot stamp steel material |
Family Cites Families (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS4849186A (en) | 1971-10-23 | 1973-07-11 | ||
JPS582511A (en) | 1981-06-26 | 1983-01-08 | Sanyo Electric Co Ltd | Petroleum combustor with up and down type wick |
JPH01152296A (en) * | 1987-12-10 | 1989-06-14 | Kawasaki Steel Corp | Method for electroplating steel sheet with zn-ni alloy |
FR2807447B1 (en) | 2000-04-07 | 2002-10-11 | Usinor | METHOD FOR MAKING A PART WITH VERY HIGH MECHANICAL CHARACTERISTICS, SHAPED BY STAMPING, FROM A STRIP OF LAMINATED AND IN PARTICULAR HOT ROLLED AND COATED STEEL SHEET |
US7650547B2 (en) | 2007-02-28 | 2010-01-19 | Verigy (Singapore) Pte. Ltd. | Apparatus for locating a defect in a scan chain while testing digital logic |
CN101508854B (en) * | 2009-03-24 | 2011-03-23 | 机械科学研究总院先进制造技术研究中心 | Ultrahigh-strength steel plate heat-punch member high-temperature oxidation resistant lubricate paint |
EP2703511B1 (en) * | 2011-04-27 | 2018-05-30 | Nippon Steel & Sumitomo Metal Corporation | Steel sheet for hot stamping members and method for producing same |
CN105908226B (en) * | 2011-06-07 | 2018-07-17 | 杰富意钢铁株式会社 | Hot pressing steel plate |
JP5880321B2 (en) * | 2012-07-09 | 2016-03-09 | 新日鐵住金株式会社 | Manufacturing method of high strength steel molded parts |
JP6264818B2 (en) * | 2013-10-03 | 2018-01-24 | 新日鐵住金株式会社 | Hot stamping steel manufacturing method, hot stamping steel plate manufacturing method and hot stamping steel plate |
JP6171872B2 (en) * | 2013-11-12 | 2017-08-02 | 新日鐵住金株式会社 | Hot stamping steel manufacturing method, hot stamping steel plate manufacturing method and hot stamping steel plate |
-
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Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2159292A1 (en) * | 2007-06-15 | 2010-03-03 | Sumitomo Metal Industries, Ltd. | Process for manufacturing shaped article |
US20120164472A1 (en) * | 2009-08-25 | 2012-06-28 | Thyssenkrupp Steel Europe Ag | Method of Producing a Steel Component Provided with a Metallic Coating Giving Protection Against Corrosion, and a Steel Component |
US20130252017A1 (en) * | 2010-11-25 | 2013-09-26 | Jfe Steel Corporation | Steel sheet for hot pressing and method for manufacturing hot-pressed member using the same |
JP2015104753A (en) * | 2013-12-02 | 2015-06-08 | 新日鐵住金株式会社 | Manufacturing method of hot stamp steel material and hot stamp steel material |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US11530474B2 (en) | 2018-02-15 | 2022-12-20 | Nippon Steel Corporation | Fe—Al-based plated hot-stamped member and manufacturing method of Fe—Al-based plated hot-stamped member |
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