JP2022087659A - Steel component manufacturing method - Google Patents

Steel component manufacturing method Download PDF

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JP2022087659A
JP2022087659A JP2020199719A JP2020199719A JP2022087659A JP 2022087659 A JP2022087659 A JP 2022087659A JP 2020199719 A JP2020199719 A JP 2020199719A JP 2020199719 A JP2020199719 A JP 2020199719A JP 2022087659 A JP2022087659 A JP 2022087659A
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shape
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steel part
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JP7448464B2 (en
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寛之 田中
Hiroyuki Tanaka
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Kobe Steel Ltd
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Kobe Steel Ltd
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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
    • 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

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  • Mechanical Engineering (AREA)
  • Shaping Metal By Deep-Drawing, Or The Like (AREA)

Abstract

To provide a manufacturing method which can easily mold a steel component with high dimensional accuracy even if the same has a complex shape and high strength.SOLUTION: A method for manufacturing a steel component, which has a shape curved in a longer direction, of which a section perpendicular to the longer direction is U-shaped or hat-shaped, and which has a step part with a divergent shape toward an opening on a vertical wall part on a curved recess side, includes: a first process in which an intermediate component, of which a length of the step part in the section perpendicular to the longer direction is same as the steel component in a top view when compared with the steel component, and which has a shape longer than that of the steel component in a cross-sectional view, is manufactured by use of a molding material; and a second process in which the intermediate component is molded by a metal mold of which a vertical wall part on a curved recess side has a shape same as that of the steel component to deform the shape of the vertical wall part on the curved recess side of the intermediate component to the shape of the vertical wall part on the curved recess side of the steel component.SELECTED DRAWING: Figure 6

Description

本発明は、鋼部品の製造方法に関する。 The present invention relates to a method for manufacturing a steel part.

近年、自動車車体の衝突安全性向上と軽量化を両立させるために、車体構造部品に高強度鋼材が適用されつつある。しかし、高強度鋼材をプレス成形して車体構造部品を製造すると、スプリングバックなどの成形不良が生じやすい。特に、車体構造部品として例えばＡピラーのようなコの字型又はハット型の断面を有し、長手方向に湾曲した部品の場合、スプリングバックなどの成形不良が生じて形状・寸法の精度不良が生じやすい。 In recent years, high-strength steel materials have been applied to vehicle body structural parts in order to achieve both improvement in collision safety and weight reduction of automobile bodies. However, when high-strength steel materials are press-molded to manufacture vehicle body structural parts, molding defects such as springback are likely to occur. In particular, in the case of a vehicle body structural part having a U-shaped or hat-shaped cross section such as an A-pillar and curved in the longitudinal direction, molding defects such as springback occur and the shape and dimensions are inaccurate. It is easy to occur.

上記精度不良を解消することを目的として、特許文献１には、ダイとパンチの相対的な直進移動によって金属板を成形するプレス成形方法において、プレス末期工程のプレス下死点前で縮みフランジ成形部位となる部分に複数の余肉ビードを形成し、縮みフランジ成形部位に引張応力を与えて、縮みフランジ成形部位の残留応力を平準化することで、プレス成形品の残留応力を平準化することが示されている。 For the purpose of eliminating the above-mentioned inaccuracy, Patent Document 1 describes in a press forming method of forming a metal plate by a relative linear movement of a die and a punch, which shrinks and flanges before the bottom dead point of the press in the final press process. By forming multiple surplus bead in the part to be the part and applying tensile stress to the shrinking flange molding part to level the residual stress of the shrinking flange molding part, the residual stress of the press-molded product is leveled. It is shown.

特許文献２には、コの字型又はハット型の断面で、長手方向に湾曲した形状を有する金属製部材を成形する方法であって、金属製部材の長手方向における領域のうち、湾曲部を含む一部については、第一成形工程で、製品形状と同一曲率半径で、かつ前記製品形状より幅を大きくして中間品を成形し、第二成形工程で、前記第一成形工程における幅より小さく、曲率半径を変えずに成形し、前記湾曲部を含む一部以外の残部の箇所については、前記第一成形工程と前記第二成形工程で金型の幅及び曲率半径を変えずに成形して、成形品全体を製品形状又は略製品形状とすることが示されている。 Patent Document 2 describes a method of forming a metal member having a U-shaped or hat-shaped cross section and having a shape curved in the longitudinal direction, wherein the curved portion of the region of the metal member in the longitudinal direction is formed. For a part including, in the first molding step, the intermediate product is molded with the same radius of curvature as the product shape and wider than the product shape, and in the second molding step, the width is larger than the width in the first molding step. It is small and molded without changing the radius of curvature, and the remaining part other than a part including the curved portion is molded without changing the width and radius of curvature of the mold in the first molding step and the second molding step. Therefore, it is shown that the entire molded product has a product shape or a substantially product shape.

更に特許文献３には、コの字型又はハット型の断面で、長手方向に湾曲した形状を有する金属製部材を成形する方法であって、前記金属製部材に形成される複数の湾曲部のうち、少なくとも１つの湾曲部については、第一成形工程で、製品形状より大きい曲率半径として中間品を成形し、第二成形工程で、前記第一成形工程における曲率半径より小さく成形し、前記少なくとも１つの湾曲部以外の残部の箇所については、前記第一成形工程と前記第二成形工程で金型の曲率半径を変えずに成形して、成形品全体を製品形状又は略製品形状とすることが示されている。 Further, Patent Document 3 describes a method of forming a metal member having a U-shaped or hat-shaped cross section and having a shape curved in the longitudinal direction, wherein a plurality of curved portions formed on the metal member are formed. Of these, at least one curved portion is formed by molding an intermediate product with a radius of curvature larger than the product shape in the first molding step, and molding smaller than the radius of curvature in the first molding step in the second molding step. The remaining portion other than one curved portion shall be molded without changing the radius of curvature of the mold in the first molding step and the second molding step, and the entire molded product shall have a product shape or a substantially product shape. It is shown.

特開２００９－２５５１１７号公報Japanese Unexamined Patent Publication No. 2009-255117 特開２０１０－６４１３７号公報Japanese Unexamined Patent Publication No. 2010-64137 特開２０１０－６４１３８号公報Japanese Unexamined Patent Publication No. 2010-64138

特許文献１では、フランジ成形部位の残留応力の平準化を目的に、伸びフランジ部にビードを成形する中間成形と、ビードを潰す成形工程を実施している。しかしこの方法は、フランジ部の形状を制御する方法であって、コの字型又はハット型の部品の縦壁部に生じた残留応力を低減するものではない。 In Patent Document 1, for the purpose of leveling the residual stress of the flange forming portion, an intermediate forming of forming a bead on the stretched flange portion and a forming step of crushing the bead are carried out. However, this method is a method of controlling the shape of the flange portion, and does not reduce the residual stress generated in the vertical wall portion of the U-shaped or hat-shaped component.

特許文献２および３では、第一成形工程において、上面図でみたときに、長手方向の線長を長めに変化させた中間品を形成し、次いで第二成形工程で最終製品の形状へと成形することで、長手方向の残留応力を減少させている。しかし、長手方向の線長を長めとした場合、最終形状とするための成形工程において、金型の据わりが悪いことがある。また、特許文献２および３は、縦壁面が複雑形状の部品を製造するものではなく、該複雑形状に応じた、部分的な残留応力の低減手段が求められている。 In Patent Documents 2 and 3, in the first molding step, an intermediate product having a longer line length in the longitudinal direction is formed when viewed from the top view, and then in the second molding step, it is molded into the shape of the final product. By doing so, the residual stress in the longitudinal direction is reduced. However, when the line length in the longitudinal direction is long, the mold may not be set properly in the molding process for obtaining the final shape. Further, Patent Documents 2 and 3 do not manufacture parts having a complicated vertical wall surface, and there is a demand for a means for reducing partial residual stress according to the complicated shape.

本発明は、上記事情に鑑みてなされたものであって、その目的は、形状が複雑かつ高強度の鋼部品を、形状・寸法精度良く、容易に成形することのできる製造方法を提供することにある。 The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a manufacturing method capable of easily forming a steel part having a complicated shape and high strength with good shape and dimensional accuracy. It is in.

本発明の態様１は、
長手方向に湾曲した形状を有し、該長手方向に垂直な断面の形状が、コの字型またはハット型であり、湾曲凹部側の縦壁部に、開口部に向かって末広がり形状の段差部を有する、鋼部品を製造する方法であって、
成形用材料を用い、長手方向に垂直な断面における段差部の線長が、前記鋼部品と比較したときに、上面視で前記鋼部品と同じであって、断面視で前記鋼部品よりも長い形状を有する、中間部品を製造する第１工程と、
前記中間部品を用い、湾曲凹部側の縦壁部が鋼部品と同じ形状の金型で成形して、前記中間部品の湾曲凹部側の縦壁部の形状を、鋼部品の湾曲凹部側の縦壁部の形状に変形させる第２工程と
を含む、鋼部品の製造方法である。 Aspect 1 of the present invention is
It has a shape curved in the longitudinal direction, and the shape of the cross section perpendicular to the longitudinal direction is U-shaped or hat-shaped. Is a method of manufacturing steel parts, which has
Using a forming material, the line length of the stepped portion in the cross section perpendicular to the longitudinal direction is the same as the steel part in the top view and longer than the steel part in the cross section when compared with the steel part. The first step of manufacturing intermediate parts with a shape,
Using the intermediate part, the vertical wall portion on the curved concave portion side is molded with a mold having the same shape as the steel part, and the shape of the vertical wall portion on the curved concave portion side of the intermediate part is changed to the vertical wall portion on the curved concave portion side of the steel part. It is a method for manufacturing a steel part, which includes a second step of transforming the shape of a wall portion.

本発明の態様２は、
前記中間部品の長手方向に垂直な断面における段差部の線長が、断面視で、前記鋼部品の長手方向に垂直な断面における段差部の線長の１．００倍超、１．１０倍以下の長さである、態様１に記載の鋼部品の製造方法である。 Aspect 2 of the present invention is
The line length of the stepped portion in the cross section perpendicular to the longitudinal direction of the intermediate part is more than 1.00 times and 1.10 times or less of the line length of the stepped portion in the cross section perpendicular to the longitudinal direction of the steel part. The method for manufacturing a steel part according to the first aspect, which is the length of the above.

本発明の態様３は、
前記鋼部品を構成する鋼板の引張強さが、９８０ＭＰａ以上である、態様１または２に記載の鋼部品の製造方法である。 Aspect 3 of the present invention is
The method for manufacturing a steel part according to aspect 1 or 2, wherein the steel plate constituting the steel part has a tensile strength of 980 MPa or more.

本発明によれば、形状が複雑かつ高強度の鋼部品を、形状・寸法精度良く、容易に成形することのできる、鋼部品の製造方法を提供できる。 INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a method for manufacturing a steel part, which can easily form a steel part having a complicated shape and high strength with good shape and dimensional accuracy.

本発明の一実施形態に係る鋼部品の模式斜視図である。It is a schematic perspective view of the steel part which concerns on one Embodiment of this invention. 本発明の一実施形態に係る鋼部品の模式上面図である。It is a schematic top view of the steel part which concerns on one Embodiment of this invention. 本発明の一実施形態において、長手方向に垂直な断面における段差部の線長を断面視したときの、該線長の両端を説明する模式図である。In one embodiment of the present invention, it is a schematic diagram explaining both ends of the line length when the line length of the step portion in the cross section perpendicular to the longitudinal direction is viewed in cross section. 本発明の一実施形態に係る中間部品の模式斜視図である。It is a schematic perspective view of the intermediate part which concerns on one Embodiment of this invention. 本発明の一実施形態に係る中間部品の、（ａ）長手方向に垂直な方向の模式断面図と、（ｂ）模式上面図である。It is (a) the schematic sectional view in the direction perpendicular to the longitudinal direction, and (b) the schematic top view of the intermediate part which concerns on one Embodiment of this invention. 図５の模式断面図の拡大図である。FIG. 5 is an enlarged view of a schematic cross-sectional view of FIG. 図６の模式断面図における段差部の拡大図である。It is an enlarged view of the step portion in the schematic cross-sectional view of FIG. 本発明の他の実施形態に係る中間部品の段差部を適用する位置を例示する図である。It is a figure which illustrates the position to which the step portion of the intermediate component which concerns on other embodiment of this invention is applied. 実施例で対象とした鋼部品の模式上面図である。It is a schematic top view of the steel part targeted in an Example. 図９のＡ－Ａ線における断面図である。9 is a cross-sectional view taken along the line AA of FIG. 実施例における工程図である。It is a process diagram in an Example. 実施例における第１工程（ドロー成形）の成形手順を示す模式断面図であり、（ａ）が成形前、（ｂ）が成形中、（ｃ）が成形後である。It is a schematic cross-sectional view which shows the molding procedure of the 1st step (draw molding) in an Example, (a) is before molding, (b) is molding, (c) is after molding. 実施例における第２工程（フォーム成形）の成形手順を示す模式断面図であり、（ａ）が成形前、（ｂ）が成形中、（ｃ）が成形後である。It is a schematic cross-sectional view which shows the molding procedure of the 2nd step (form molding) in an Example, (a) is before molding, (b) is molding, (c) is after molding. 実施例で用いた鋼板の特性を示す図である。It is a figure which shows the characteristic of the steel plate used in an Example. 実施例で求めた応力分布図であり、（ａ）が比較例の結果、（ｂ）が実施例の結果である。It is a stress distribution map obtained in the example, (a) is the result of the comparative example, and (b) is the result of the example. 実施例で成形した中間部品の段差部の線長を示す図である。It is a figure which shows the line length of the step portion of the intermediate part molded in an Example.

以下、本発明の１つの実施形態を、図面を示して説明するが、該実施形態は、本発明の技術的思想を具体化するために例示するものであって、本発明の技術的思想はかかる実施形態に示された形状に限定されるものではない。 Hereinafter, one embodiment of the present invention will be described with reference to the drawings, and the embodiments are exemplified in order to embody the technical idea of the present invention. The shape is not limited to the shape shown in such an embodiment.

図１は、本実施形態で対象とする鋼部品１を模式的に示した斜視図である。また図２は、上記鋼部品１を模式的に示した上面図である。この図１および図２に示す通り、本実施形態で対象とする鋼部品１は、長手方向Ｌ１に湾曲した形状を有し、該長手方向に垂直な断面が、コの字型またはハット型であり、開口部２に向かって末広がり形状の段差部３を有している。また図１および図２で示された鋼部品１は、天板部４と縦壁部５Ａ、５Ｂを有し、２つの縦壁部のうち、湾曲凹部側の縦壁部５Ａは、段差部３とフランジ部６を有している。図１においてＷは、鋼部品１の幅方向を示している。 FIG. 1 is a perspective view schematically showing a steel part 1 targeted in the present embodiment. Further, FIG. 2 is a top view schematically showing the steel part 1. As shown in FIGS. 1 and 2, the steel part 1 targeted in the present embodiment has a shape curved in the longitudinal direction L1, and the cross section perpendicular to the longitudinal direction is U-shaped or hat-shaped. There is a stepped portion 3 having a divergent shape toward the opening 2. Further, the steel component 1 shown in FIGS. 1 and 2 has a top plate portion 4 and vertical wall portions 5A and 5B, and of the two vertical wall portions, the vertical wall portion 5A on the curved recess side is a stepped portion. It has 3 and a flange portion 6. In FIG. 1, W indicates the width direction of the steel component 1.

上記鋼部品１を得るべく、金型で成形したときに、得られた鋼部品１の端部の位置が、図２にて下向きの矢印で示す通り低下し、鋼部品１が湾曲凹部側に変形する、といった形状精度不良、具体的には「首振り」が生じる。この形状精度不良は、鋼部品に用いる鋼板の強度が高いほど生じやすい。本発明者は、上記首振りが発生する原因について調べた。特に、成形後の部品の応力分布を、成形条件を設定したシミュレーション解析で求めた。その結果、後述する実施例において図１５（ａ）として示す通り、長手方向の湾曲凹部側の縦壁部に形成された段差部近辺で、高い引張応力が生じていることがわかった。そこで、この段差部の引張応力に着目し、上記首振りを抑制すべく鋭意研究を行ったところ、段差部の形状を利用して成形工程を設計すれば、引張応力が生じる部分に圧縮応力を生じさせ、結果として成形後の残留応力を低減でき、かつ金型を使用して成形するにあたり、金型の据わり良く成形できることを見出した。 When the steel part 1 was molded with a mold to obtain the steel part 1, the position of the end portion of the obtained steel part 1 was lowered as shown by the downward arrow in FIG. 2, and the steel part 1 was moved to the curved concave portion side. Poor shape accuracy such as deformation, specifically, "swinging" occurs. This poor shape accuracy is more likely to occur as the strength of the steel sheet used for the steel part increases. The present inventor investigated the cause of the above-mentioned swing. In particular, the stress distribution of the part after molding was obtained by simulation analysis with the molding conditions set. As a result, as shown in FIG. 15A in the examples described later, it was found that high tensile stress was generated in the vicinity of the step portion formed on the vertical wall portion on the curved recess side in the longitudinal direction. Therefore, focusing on the tensile stress of this stepped portion, we conducted diligent research to suppress the above-mentioned swing. If the molding process is designed using the shape of the stepped portion, compressive stress will be applied to the portion where the tensile stress is generated. It was found that the residual stress after molding can be reduced as a result, and that the mold can be easily set when molding using the mold.

具体的には、鋼部品の製造方法として、成形用材料を用い、まず、長手方向に垂直な断面における段差部の線長が、前記鋼部品と比較したときに、上面視で前記鋼部品と同じであって、断面視で前記鋼部品よりも長い形状を有する、中間部品を一旦製造する第１工程と、前記中間部品を用い、湾曲凹部側の縦壁部が鋼部品と同じ形状の金型で成形して、前記中間部品の湾曲凹部側の縦壁部の形状を、鋼部品の湾曲凹部側の縦壁部の形状に変形させる第２工程とを有するようにすればよいことを見出した。この様に本発明では、鋼部品の縦壁部に段差部を有し、長手方向に垂直な断面における段差部の線長が、中間部品と鋼部品で比較したときに、上面視では同じであって、断面視では中間部品の方が鋼部品よりも長い。上記同じ線長とは、長さ・位置ともに同一の線であることをいう。これらの点で、本実施形態に係る鋼部品特許文献２および特許文献３とは異なる。 Specifically, as a method for manufacturing a steel part, a molding material is used, and first, when the line length of the step portion in the cross section perpendicular to the longitudinal direction is compared with the steel part, the steel part and the steel part are viewed from above. The first step of temporarily manufacturing an intermediate part, which is the same and has a shape longer than the steel part in terms of cross section, and the gold having the same shape as the steel part in the vertical wall portion on the curved recess side using the intermediate part. It has been found that the intermediate part may be molded with a mold to have a second step of transforming the shape of the vertical wall portion on the curved concave portion side of the intermediate part into the shape of the vertical wall portion on the curved concave portion side of the steel part. rice field. As described above, in the present invention, the vertical wall portion of the steel part has a stepped portion, and the line length of the stepped portion in the cross section perpendicular to the longitudinal direction is the same in the top view when the intermediate part and the steel part are compared. Therefore, in the cross-sectional view, the intermediate parts are longer than the steel parts. The same line length means that the line has the same length and position. In these respects, it is different from Patent Document 2 and Patent Document 3 for steel parts according to the present embodiment.

本実施形態では、長手方向に垂直な断面における段差部の形状において、断面視したときに、段差部の線長の両端が鋼部品と中間部品で同一であって、段差部の線長が鋼部品よりも中間部品の方が長い。前記段差部の線長とは、段差部を構成する線長の一方の端から他方の端までをいい、例えば、後述する図６に模式的に示すような段差部の場合、一つの凹状角部Ｐ１から他の凹状角部Ｐ２までをいう。または、例えば図３に例示する通り凹状角部が曲率Ｒを有する場合、縦壁を形成する直線Ａと断面線Ｒ１の接点を一方の端Ｐ１１とし、縦壁（フランジ部）を形成する直線Ｂと断面線Ｒ２の接点を他方の端Ｐ２１とし、これら一方の端Ｐ１１から他方の端Ｐ２１までをいう。本実施形態では、これら２つの端の間で線長の長さを変更すればよい。 In the present embodiment, in the shape of the step portion in the cross section perpendicular to the longitudinal direction, both ends of the line length of the step portion are the same for the steel part and the intermediate part when viewed in cross section, and the line length of the step portion is steel. Intermediate parts are longer than parts. The line length of the step portion means from one end to the other end of the line length constituting the step portion. For example, in the case of the step portion as schematically shown in FIG. 6 described later, one concave angle. Refers to the portion P1 to the other concave corner portion P2. Alternatively, for example, when the concave corner portion has a curvature R as illustrated in FIG. 3, the contact point between the straight line A forming the vertical wall and the cross-sectional line R1 is set as one end P11, and the straight line B forming the vertical wall (flange portion). And the contact point of the cross-sectional line R2 is the other end P21, and means from one end P11 to the other end P21. In this embodiment, the length of the line length may be changed between these two ends.

以下、本実施形態に係る鋼部品の製造方法について詳述する。 Hereinafter, the method for manufacturing steel parts according to the present embodiment will be described in detail.

（第１工程）
第１工程では、成形用材料を用い、長手方向に垂直な断面における段差部の線長が、前記鋼部品と比較したときに、上面視で前記鋼部品と同じであって、断面視で前記鋼部品よりも長い形状を有する、中間部品を製造する。 (First step)
In the first step, a molding material is used, and the line length of the step portion in the cross section perpendicular to the longitudinal direction is the same as that of the steel part in the top view when compared with the steel part, and the cross section is the same. Manufacture intermediate parts that have a longer shape than steel parts.

本工程で製造する中間部品の模式的な斜視図を図４、中間部品の長手方向に垂直な断面模式図を図５（ａ）、中間部品の長手方向の上面模式図を図５（ｂ）に示す。図４および図５に示す点線は、第２工程で成形する鋼部品の形状を示す。図５（ｂ）に両矢印で示す通り、長手方向に垂直な断面における段差部の線長は、上面視したときに、中間部品と鋼部品で同じである。図６は、図５（ａ）の断面図を拡大した模式図である。図６は、長手方向に垂直な断面における段差部の線長を断面視した図でもある。この図６に示す通り、中間部品の段差部の線長Ｌ２２を、鋼部品の段差部の線長Ｌ２１よりも長くする。更に図６に示す通り、段差部を構成する線長の両端部Ｐ１およびＰ２の位置は、鋼部品の段差部の線長の両端部Ｐ１およびＰ２と同位置である。 FIG. 4 is a schematic perspective view of the intermediate parts manufactured in this step, FIG. 5A is a schematic cross-sectional view perpendicular to the longitudinal direction of the intermediate parts, and FIG. 5B is a schematic top view of the intermediate parts in the longitudinal direction. Shown in. The dotted line shown in FIGS. 4 and 5 indicates the shape of the steel part to be formed in the second step. As shown by double-headed arrows in FIG. 5B, the line length of the stepped portion in the cross section perpendicular to the longitudinal direction is the same for the intermediate part and the steel part when viewed from above. FIG. 6 is an enlarged schematic view of the cross-sectional view of FIG. 5 (a). FIG. 6 is also a cross-sectional view of the line length of the stepped portion in the cross section perpendicular to the longitudinal direction. As shown in FIG. 6, the line length L22 of the stepped portion of the intermediate part is made longer than the line length L21 of the stepped portion of the steel part. Further, as shown in FIG. 6, the positions of both ends P1 and P2 of the line length constituting the step portion are the same as the positions of both ends P1 and P2 of the line length of the step portion of the steel component.

中間部品の段差部の線長Ｌ２２を上記形態とすることによって、第２工程で、鋼部品形状の金型で成形時に、上記断面における（中間部品の段差部の線長Ｌ２２－鋼部品の段差部の線長Ｌ２１）で表される余剰線長部分が、潰されて材料が長手方向に広がろうとするが、周囲の材料に阻まれて圧縮を受け、圧縮応力が発生する。その結果、第１工程の中間部品で生じる引張応力が、次工程の第２工程の成形で生じる圧縮応力で打ち消され、残留応力が低減されて、高い引張応力が原因で生じていた首振りが抑制されると考えられる。 By making the line length L22 of the stepped portion of the intermediate part into the above-mentioned form, in the second step, when molding with a mold having the shape of a steel part, (the line length L22 of the stepped portion of the intermediate part-the step of the steel part) in the above cross section. The excess line length portion represented by the line length L21) of the portion is crushed and the material tries to spread in the longitudinal direction, but is blocked by the surrounding material and is compressed, and compressive stress is generated. As a result, the tensile stress generated in the intermediate part of the first step is canceled by the compressive stress generated in the molding of the second step of the next step, the residual stress is reduced, and the swing caused by the high tensile stress is generated. It is thought to be suppressed.

また、中間部品の段差部を構成する線長の両端部Ｐ１、Ｐ２を、鋼部品の段差部の線長の両端部Ｐ１、Ｐ２と一致させることによって、第２工程で中間部品に成形加工を施すときに、中間部品の段差部に、鋼部品の段差部の形状の金型を嵌め込み易く、結果として、確実に成形されて圧縮応力を付与することができる。 Further, by matching both ends P1 and P2 of the line length constituting the step portion of the intermediate part with both ends P1 and P2 of the line length of the step portion of the steel part, the intermediate part can be formed into the intermediate part in the second step. At the time of application, it is easy to fit the mold in the shape of the stepped portion of the steel part into the stepped portion of the intermediate part, and as a result, it can be reliably formed and compressive stress can be applied.

前記中間部品の段差部を構成する線長は、鋼部品の段差部の線長に対して、比率が１．００超の長さであればよい。一方、鋼部品の金型を中間部品により容易に篏合させて、中間部品に確実に圧縮応力を付与する観点からは、上記比率を１．１０以下とすることが好ましく、より好ましくは１．０６以下である。 The wire length constituting the stepped portion of the intermediate component may be a length having a ratio of more than 1.00 with respect to the wire length of the stepped portion of the steel component. On the other hand, from the viewpoint of easily mating the molds of the steel parts with the intermediate parts and surely applying the compressive stress to the intermediate parts, the above ratio is preferably 1.10 or less, and more preferably 1. It is 06 or less.

中間部品の断面における段差部の形状は、好ましくは上記線長の比率を満たして、第２工程で、鋼部品の金型を容易に篏合できれば特に限定されない。図７は、前記図６の一部を拡大したものである。鋼部品の断面における段差部の形状が、例えば図７の破線の通りである場合、中間部品の段差部の線長として余剰線長は、例えば次のようにして決定することができる。すなわち、端部Ｐ１を軸として、鋼部品の段差部の天井面Ａ１と中間部品の段差部の天井面Ｂ１がなす角度をθ１としたとき、角度θ１を、例えば１度以上、１０度以下の範囲で変更することが挙げられる。また、端部Ｐ２を軸として、鋼部品の段差部の縦壁面Ａ２と中間部品の段差部の縦壁面Ｂ２がなす角度をθ２としたとき、角度θ２を、例えば１度以上、１０度以下の範囲で変更することが挙げられる。角度θ２は、鋼部品の金型を容易に篏合させて良好に成形する観点から、底面と縦壁面Ｂ２がなす角度θ３が９０度を超えない範囲とする。 The shape of the stepped portion in the cross section of the intermediate part is not particularly limited as long as it satisfies the ratio of the above line lengths and can easily fit the mold of the steel part in the second step. FIG. 7 is an enlargement of a part of FIG. When the shape of the stepped portion in the cross section of the steel part is as shown by the broken line in FIG. 7, for example, the surplus line length as the line length of the stepped portion of the intermediate part can be determined as follows. That is, when the angle formed by the ceiling surface A1 of the stepped portion of the steel part and the ceiling surface B1 of the stepped portion of the intermediate part is θ1 with the end portion P1 as the axis, the angle θ1 is, for example, 1 degree or more and 10 degrees or less. It can be changed within the range. Further, when the angle formed by the vertical wall surface A2 of the stepped portion of the steel part and the vertical wall surface B2 of the stepped portion of the intermediate part is θ2 with the end portion P2 as the axis, the angle θ2 is, for example, 1 degree or more and 10 degrees or less. It can be changed within the range. The angle θ2 is set within a range in which the angle θ3 formed by the bottom surface and the vertical wall surface B2 does not exceed 90 degrees from the viewpoint of easily fitting the molds of the steel parts and forming them well.

本実施形態の製造方法の説明に用いる図４および図５では、長手方向の全域にわたって、断面を上記形態とした例を挙げているが、これに限定されず、長手方向における一箇所または断続的な複数箇所において、断面を上記形態とすることができる。本発明によれば、長手方向において上記圧縮応力を付与したい箇所の断面を、上記形態とすることによって、該箇所に圧縮応力を部分的に付与できる。そのため、圧縮応力を付与したい任意の複数箇所で、上記断面の形態を変化させることができる。その点で、特許文献２および特許文献３よりも、圧縮応力の付与の自由度が高く、必要に応じた圧縮応力の付与を行うことができる。例えば、図８に斜線部分として示す通り、所望の複数領域で断面形状を変化させて、圧縮応力を付与することができる。 In FIGS. 4 and 5 used for explaining the manufacturing method of the present embodiment, an example in which the cross section is the above-described embodiment is given over the entire area in the longitudinal direction, but the present invention is not limited to this, and the cross section is not limited to this, and is one place or intermittent in the longitudinal direction. The cross section can be in the above-mentioned form at a plurality of locations. According to the present invention, by forming the cross section of the portion to which the compressive stress is desired to be applied in the longitudinal direction into the above-described form, the compressive stress can be partially applied to the portion. Therefore, the shape of the cross section can be changed at any plurality of places where compressive stress is desired to be applied. In that respect, the degree of freedom in applying compressive stress is higher than that in Patent Document 2 and Patent Document 3, and compressive stress can be applied as needed. For example, as shown by the shaded area in FIG. 8, the cross-sectional shape can be changed in a desired plurality of regions to apply compressive stress.

第１工程に供する成形用材料は、未加工の鋼板の他、対象部分以外の成形が施された中間製品であってもよい。 The molding material used in the first step may be an unprocessed steel sheet or an intermediate product formed by molding other than the target portion.

第１工程では、上記中間部品を成形できればよく、成形方法については問わない。例えばプレス成形として、ドロー（絞り）成形、またはフォーム（曲げ）成形を行うことができる。上記中間部品は、長手方向に垂直な断面における段差部の形状が、前記鋼部品と比較したときに、上面視で前記鋼部品と同じ線長であって、断面視で前記鋼部品よりも長い線長を有する、金型を用いて成形することができる。 In the first step, it is sufficient that the intermediate parts can be molded, and the molding method does not matter. For example, as press molding, draw (drawing) molding or foam (bending) molding can be performed. The intermediate part has the same line length as the steel part in the top view and is longer than the steel part in the cross section when the shape of the step portion in the cross section perpendicular to the longitudinal direction is compared with the steel part. It can be molded using a mold having a wire length.

第１工程として、例えばＡピラーを得るにあたり、例えばドロー（絞り）成形を行う場合、冷間加工（常温）であって、プレス速度：実機で４０～６０ＳＰＭ程度（解析の場合は、成形速度の影響がないため１０００ＳＰＭ）、ホルダー加圧：６０～１００ｔｏｎの条件とすることができる。またドロー成形では、例えば後述する実施例に示す通り、ダイ、ポンチ、ホルダー（しわ押さえ）を備えた成形装置において、ダイとホルダーで鋼板縁部を挟み、縦壁部に張力を付与しながら成形を行うことが挙げられる。 As the first step, for example, in order to obtain an A-pillar, for example, when drawing (drawing) molding is performed, it is cold working (normal temperature), and the pressing speed: about 40 to 60 SPM in the actual machine (in the case of analysis, the molding speed). Since there is no effect, the conditions can be 1000 SPM), holder pressurization: 60 to 100 ton. In draw molding, for example, as shown in Examples described later, in a molding apparatus provided with a die, a punch, and a holder (wrinkle retainer), the steel plate edge is sandwiched between the die and the holder, and the vertical wall is tensioned. Is mentioned.

上記首振り等の寸法精度の低下は、鋼部品を構成する鋼板の引張強さが高いほど生じやすい。よって本発明の製造方法は、９８０ＭＰａ以上の引張強さを有する鋼板を原板として用いて成形する場合に、より効果を発揮させることができる。上記引張強さは、１１８０ＭＰａ以上であってもよい。引張強さが上昇しても、本実施形態に係る構成と作用効果に変更はないため、本実施形態の鋼部品の製造に用いる鋼板の引張強さの上限は特に限定されない。例えば、製造時に使用する金型の寿命等の観点から、引張強さの上限をおおよそ１８００ＭＰａとすることができる。上記鋼板として、例えば厚さが０．８ｍｍ以上、２．０ｍｍ以下のものを対象とすることができる。 The decrease in dimensional accuracy such as swinging is more likely to occur as the tensile strength of the steel plate constituting the steel part is higher. Therefore, the manufacturing method of the present invention can be more effective when the steel sheet having a tensile strength of 980 MPa or more is used as the original plate for molding. The tensile strength may be 1180 MPa or more. Even if the tensile strength increases, the configuration and working effect according to the present embodiment do not change, so that the upper limit of the tensile strength of the steel sheet used for manufacturing the steel parts of the present embodiment is not particularly limited. For example, from the viewpoint of the life of the mold used at the time of manufacturing, the upper limit of the tensile strength can be set to about 1800 MPa. As the steel sheet, for example, a steel sheet having a thickness of 0.8 mm or more and 2.0 mm or less can be targeted.

前記第１工程後であって、第２工程の前に、ピアス加工（打ち抜き穴加工）、外周トリム加工（せん断加工）等の加工を施す工程を設けてもよい。これらの加工とともに、またはこれらの加工の代わりに、本実施形態にて成形の対象となる段差部以外の部位、例えば前記図１における縦壁部５Ｂを最終製品の形状とする加工を行ってから、第２加工を行ってもよい。 After the first step and before the second step, a step of performing piercing (punching hole machining), outer peripheral trimming (shearing), or the like may be provided. After performing these processes, or instead of these processes, a portion other than the step portion to be molded in the present embodiment, for example, the vertical wall portion 5B in FIG. 1 is processed into the shape of the final product. , The second processing may be performed.

（第２工程）
前記第１工程の後、中間部品を、段差部が最終製品と同じ形状の金型で成形して、前記段差部が最終製品と同じ形状の鋼部品を製造する。 (Second step)
After the first step, the intermediate parts are molded with a mold having the same stepped portion as the final product, and a steel part having the same stepped portion as the final product is manufactured.

第２工程で、前記中間部品に対し、前記段差部が最終製品と同じ形状の金型で成形することによって、前述したように、成形後の部品の段差部に圧縮応力を生じさせることができ、結果として残留応力が減少して、首振りを抑制することができる。 In the second step, by molding the stepped portion of the intermediate part with a mold having the same shape as the final product, compressive stress can be generated in the stepped portion of the molded part as described above. As a result, the residual stress is reduced and the swing can be suppressed.

本実施形態に係る鋼部品は、最終成形品であってもよいし、前記段差部以外の箇所の成形を更に行うための中間成形品であってもよい。または後述の通り、最終成形品または中間成形品に、更に成形以外の加工を施したものであってもよい。前記鋼部品が、最終成形品である場合、金型として、前記段差部以外の箇所も最終成形品と同じ形状の金型を用いればよい。前記鋼部品が、前記中間成形品である場合、少なくとも段差部が最終成形品と同じ形状の金型を用いればよい。 The steel part according to the present embodiment may be a final molded product or an intermediate molded product for further molding a portion other than the step portion. Alternatively, as described later, the final molded product or the intermediate molded product may be further subjected to processing other than molding. When the steel part is a final molded product, a mold having the same shape as the final molded product may be used for a portion other than the step portion as the mold. When the steel part is the intermediate molded product, a mold having at least a step portion having the same shape as the final molded product may be used.

第２工程では、上記鋼部品を成形できればよく、成形方法については問わない。例えばプレス成形として、ドロー（絞り）成形、フォーム（曲げ）成形を行うことができる。 In the second step, it is sufficient that the steel parts can be formed, and the forming method does not matter. For example, as press molding, draw (drawing) molding and foam (bending) molding can be performed.

第２工程として、例えばＡピラーを得るにあたり、例えばフォーム（曲げ）成形を行う場合、冷間加工（常温）であって、プレス速度：実機で４０～６０ＳＰＭ程度（解析の場合は、成形速度の影響がないため１０００ＳＰＭ）の条件とすることができる。 As a second step, for example, in obtaining an A-pillar, for example, in the case of foam (bending) molding, cold working (normal temperature), press speed: about 40 to 60 SPM in an actual machine (in the case of analysis, the molding speed). Since there is no effect, the condition can be 1000 SPM).

本実施形態における製造方法は、前記第２工程の後、前記中間成形品に対し、更に、前記段差部以外の箇所の成形を行う工程を設けてもよい。また、必要に応じて、前記最終成形品または前記中間成形品に対し、ピアス加工（打ち抜き穴加工）、外周トリム加工（せん断加工）等の成形以外の加工を施す工程を設けてもよい。 In the manufacturing method in the present embodiment, after the second step, the intermediate molded product may be further provided with a step of molding a portion other than the step portion. Further, if necessary, the final molded product or the intermediate molded product may be provided with a step other than molding, such as piercing (punching hole processing) and outer peripheral trimming (shearing).

上記例示した図面では、縦壁部５Ａに段差部を１つ有する部品について説明したが、上記段差部は、１段であっても、２段以上の多段であってもよい。また、縦壁部５Ａと縦壁部５Ｂの両方に段差部を有する部品であって、縦壁部５Ａに設けられた段差部を本実施形態の通り成形してもよい。 In the above-exemplified drawings, the component having one step portion on the vertical wall portion 5A has been described, but the step portion may be one step or a multi-step portion having two or more steps. Further, it is a component having a stepped portion in both the vertical wall portion 5A and the vertical wall portion 5B, and the stepped portion provided in the vertical wall portion 5A may be formed according to the present embodiment.

（適用部品）
本実施形態に係る鋼部品として、例えば、天板部と縦壁を有し、長手方向に湾曲し、少なくとも湾曲凹部側の縦壁部に段差部を有している形状部品、具体的に、車体構造部品に用いられるプレス成形品、例えばＡピラー、フロントピラー等が挙げられる。 (Applicable parts)
As the steel parts according to the present embodiment, for example, a shaped part having a top plate portion and a vertical wall, curved in the longitudinal direction, and having a stepped portion at least on the vertical wall portion on the curved concave portion side, specifically, Press-molded products used for vehicle body structural parts, such as A-pillars and front pillars, can be mentioned.

以下、実施例を挙げて本発明をより具体的に説明する。本発明は以下の実施例によって制限を受けるものではなく、前述および後述する趣旨に合致し得る範囲で、適宜変更を加えて実施することも可能であり、それらはいずれも本発明の技術的範囲に包含される。 Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not limited by the following examples, and can be carried out with appropriate modifications to the extent that it can meet the above-mentioned and later-described intent, and both of them are the technical scope of the present invention. Included in.

［実施例１］
実施例１では、鋼部品として、図９に模式的に示すＡピラーの製造を対象として、ＣＡＥによるシミュレーション解析を行った。上記図９におけるＡ－Ａ線の断面図が図１０である。図１０は、長手方向に垂直な断面における段差部の線長を、断面視した図でもある。図９および図１０に示す通り、対象とする鋼部品は、長手方向に沿って幅方向に湾曲し、天板部４及びフランジ部６を有し、湾曲凹部側の縦壁部５Ａに段差部３を有している。 [Example 1]
In Example 1, a simulation analysis by CAE was performed for the production of the A pillar schematically shown in FIG. 9 as a steel part. FIG. 10 is a cross-sectional view taken along the line AA in FIG. FIG. 10 is also a cross-sectional view of the line length of the stepped portion in the cross section perpendicular to the longitudinal direction. As shown in FIGS. 9 and 10, the target steel part is curved in the width direction along the longitudinal direction, has a top plate portion 4 and a flange portion 6, and has a stepped portion on the vertical wall portion 5A on the curved concave portion side. Has 3.

本実施例におけるシミュレーション解析では、図１１に示す工程の通りとした。本実施例では、第１工程としてドロー成形、第２工程としてフォーム成形を行うようにした。図１１において「ｔｒｉｍ１」では外周トリム加工（せん断加工）を行うことを意味している。また「ＳＢ１」と「ＳＢ２」は、本シミュレーション解析における、成形後のスプリングバックの計算工程を意味している。 In the simulation analysis in this example, the process shown in FIG. 11 was followed. In this embodiment, draw molding is performed as the first step, and foam molding is performed as the second step. In FIG. 11, “trim1” means that the outer peripheral trimming (shearing) is performed. Further, "SB1" and "SB2" mean the calculation process of the springback after molding in this simulation analysis.

本実施例１として、第１工程で、図１２に示す模式断面図の通り、未加工の鋼板を、（ａ）→（ｂ）→（ｃ）の通りドロー成形を行って中間部品を得た。詳細には、（ａ）成形前において、ダイ１１とホルダー１２の間に鋼板１３をセットし、（ｂ）成形中および（ｃ）成型後に示す通り、ダイ１１とホルダー１２で鋼板１３の端部を挟んだ状態で、下部からのパンチ１４で成形して、中間部品１５を得た。上記ダイ１１における段差部の形状とパンチ１４の段差部の形状、すなわち図１２（ａ）の楕円点線部分の形状は、本発明で規定する通り、中間部品の段差部の線長を鋼部品の線長よりも長い、すなわち余剰線長を設けた形状とした。この本実施例１では、鋼部品の段差部の線長に対する比率を１．０５とした。また比較例として、上記ダイ１１における段差部の形状とパンチ１４の段差部の形状が最終製品と同じ金型で成形したものも用意した。 As the first embodiment, in the first step, as shown in the schematic cross-sectional view shown in FIG. 12, the unprocessed steel sheet was drawn-formed as shown in (a) → (b) → (c) to obtain an intermediate part. .. Specifically, (a) before molding, the steel plate 13 is set between the die 11 and the holder 12, and as shown in (b) during molding and (c) after molding, the end portion of the steel plate 13 is formed by the die 11 and the holder 12. The intermediate part 15 was obtained by molding with a punch 14 from the lower part in a state of sandwiching the steel plate. The shape of the stepped portion in the die 11 and the shape of the stepped portion of the punch 14, that is, the shape of the elliptical dotted line portion in FIG. The shape is longer than the line length, that is, the shape is provided with an extra line length. In the first embodiment, the ratio of the stepped portion of the steel component to the line length is set to 1.05. Further, as a comparative example, a die 11 having a stepped portion and a punch 14 having a stepped portion formed with the same mold as the final product was also prepared.

上記第１工程後に、第２工程で、図１３に示す模式断面図の通り、上記図１２の成形で得られた中間部品を用い、（ａ）→（ｂ）→（ｃ）の通りフォーム成形を行って鋼部品を得た。なお図１３において、成形時に中間部品を上方から押さえるダイのうちの一方は、図１３（ａ）のダイ１６であり、他方のダイは中間部品の段差部から離れた位置にあり、図示していない。成形は、詳細には（ａ）成形前において、中間部品１５の上方からパッド１７で押さえ、（ｂ）成形中および（ｃ）成形後に示す通り、中間部品１５の上方のダイ１６と中間部品の下方のパンチ１８で成形し、鋼部品１９を得た。 After the first step, in the second step, as shown in the schematic cross-sectional view shown in FIG. 13, the intermediate parts obtained by the molding of FIG. 12 are used to form the foam as shown in (a) → (b) → (c). Was performed to obtain steel parts. In FIG. 13, one of the dies that press the intermediate parts from above during molding is the die 16 of FIG. 13 (a), and the other die is located at a position away from the stepped portion of the intermediate parts and is shown in the figure. do not have. In detail, the molding is performed by (a) pressing the pad 17 from above the intermediate part 15 before molding, and (b) during molding and (c) after molding, as shown above, the die 16 above the intermediate part 15 and the intermediate part. Molding was performed with the lower punch 18 to obtain a steel part 19.

シミュレーション解析では、使用材料として、図１４に示す真ひずみと真応力の関係を示す、引張強さが１５５２ＭＰａの鋼板を用いることとし、下記の解析条件および成形条件で、前述の図１１に示す工程順に加工を行うシミュレーション解析を実施した。シミュレーション解析における解析条件、上記以外の成形条件は、以下の通りとした。 In the simulation analysis, a steel sheet having a tensile strength of 1552 MPa, which shows the relationship between the true strain and the true stress shown in FIG. 14, is used as the material to be used, and the steps shown in FIG. 11 described above are used under the following analysis conditions and molding conditions. A simulation analysis was performed in which machining was performed in order. The analysis conditions in the simulation analysis and the molding conditions other than the above are as follows.

（１）解析条件
要素タイプ：完全積分（ｅｌｆｏｒｍ＝１６） ねじれ剛性付加（ＩＨＱ＝８）
積分点数：５点
摩擦係数：０．１２
要素サイズ：２ｍｍ×２ｍｍ
板厚：１．４ｍｍ
使用材料：ＣＲ１４７０ＭＳ（降伏点ＹＰ：１３１１ＭＰａ、引張強さＴＳ：１５５２ＭＰａ、伸びＥＬ：８．４％）
使用ソフト：株式会社ＪＳＯＬ社製 ＪＳＴＡＭＰ（登録商標）／ＮＶ ２．１５
ソルバー：株式会社ＪＳＯＬ社製 ＬＳ－ＤＹＮＡ（登録商標）Ｒ９．２．０倍精度 ｍｐｐ (1) Analysis condition element type: complete integral (elfform = 16) torsional rigidity addition (IHQ = 8)
Number of integration points: 5 points Friction coefficient: 0.12
Element size: 2mm x 2mm
Plate thickness: 1.4 mm
Material used: CR1470MS (yield point YP: 1311MPa, tensile strength TS: 1552MPa, elongation EL: 8.4%)
Software used: JSTAMP (registered trademark) / NV 2.15 manufactured by JSOL Co., Ltd.
Solver: LS-DYNA (registered trademark) R9.2.0 double precision mpp manufactured by JSOL Co., Ltd.

（２）成形条件
１工程目（ＤＲＡＷ）
最大速度：１０００ｍｍ／ｓｅｃ
成形圧：１０００ｔｏｎ
ＢＨＦ：７０ｔｏｎ（決め押し有）
２工程目（ＰＡＤ付きＦＯＲＭ）
最大速度：１０００ｍｍ／ｓｅｃ
成形圧：６００ｔｏｎ
ＢＨＦ：３０ｔｏｎ（決め押し有）
鋼板温度：常温 (2) Molding conditions 1st step (DRAW)
Maximum speed: 1000mm / sec
Molding pressure: 1000 ton
BHF: 70 ton (with a fixed push)
2nd process (FORM with PAD)
Maximum speed: 1000mm / sec
Molding pressure: 600 ton
BHF: 30 ton (with a fixed push)
Steel plate temperature: normal temperature

上記条件でシミュレーション解析を行った結果として、前記図９の点線楕円部分の応力を測定した結果を、図１５に示す。図１５（ａ）は比較例の結果であり、図１５（ｂ）は本発明例１の結果である。この図１５の結果から、本発明によれば、段差部の引張応力を示す色調が薄くなっており、第１工程の成形で生じた引張応力が、第２工程の成形により生じた圧縮応力で打ち消されて、引張応力が低減されたことがわかる。また、本発明例１と比較例の鋼部品の首振りの程度として、前記図９の矢印で示す部分の、第２工程で使用した金型の位置、すなわち鋼部品の金型の端部からの変位を求めた。前記図９の矢印位置から上方向がプラス、下方向がマイナスで示される。その結果を表１に示す。 As a result of performing simulation analysis under the above conditions, the result of measuring the stress of the dotted elliptical portion of FIG. 9 is shown in FIG. FIG. 15 (a) is the result of the comparative example, and FIG. 15 (b) is the result of the present invention Example 1. From the results of FIG. 15, according to the present invention, the color tone indicating the tensile stress of the stepped portion is lightened, and the tensile stress generated by the molding in the first step is the compressive stress generated by the molding in the second step. It can be seen that the tensile stress was reduced by canceling. Further, as the degree of swing of the steel parts of the first and comparative examples of the present invention, the position of the mold used in the second step, that is, from the end of the mold of the steel parts, in the portion indicated by the arrow in FIG. The displacement of was calculated. From the position of the arrow in FIG. 9, the upward direction is indicated by a plus and the downward direction is indicated by a minus. The results are shown in Table 1.

Figure 2022087659000002
Figure 2022087659000002

本発明に係る工程を経て鋼部品を製造することで、高強度であっても、首振りが低減されて形状精度の向上した鋼部品が得られることがわかる。 It can be seen that by manufacturing the steel parts through the process according to the present invention, it is possible to obtain steel parts with reduced swing and improved shape accuracy even with high strength.

［実施例２］
中間部品の段差部の線長を変更して、首振りの程度を確認した。中間部品の段差部の線長を、図１６および下記表２に示す通りとした以外は、上記本発明例１と同様にしてシミュレーション解析を行った。図１６において、Ｌ３１は本発明例１の線長、Ｌ３２は本発明例２の線長、Ｌ３３は本発明例３の線長を示す。また図１６において、点線楕円部分の拡大図を図１６下方に示す。該拡大図に示す通り、本発明例１の線長Ｌ３１の角度を、前記図７に例示のθ１としたときに、本発明例２では、角度（θ１－３度）となるように直線を描いてから線長Ｌ３２を形成し、本発明例３では、角度（θ１＋３度）となるように直線を描いてから線長Ｌ３３を形成した。上記シミュレーション解析の結果を、下記表２に示す。 [Example 2]
The line length of the stepped part of the intermediate part was changed, and the degree of swing was confirmed. Simulation analysis was performed in the same manner as in Example 1 of the present invention, except that the line length of the stepped portion of the intermediate component was set as shown in FIG. 16 and Table 2 below. In FIG. 16, L31 indicates the line length of Example 1 of the present invention, L32 indicates the line length of Example 2 of the present invention, and L33 indicates the line length of Example 3 of the present invention. Further, in FIG. 16, an enlarged view of the dotted elliptical portion is shown in the lower part of FIG. As shown in the enlarged view, when the angle of the line length L31 of the first invention example is θ1 exemplified in FIG. 7, in the second invention example 2, a straight line is drawn so as to be an angle (θ1-3 degrees). After drawing, the line length L32 was formed, and in Example 3 of the present invention, the line length L33 was formed after drawing a straight line so as to have an angle (θ1 + 3 degrees). The results of the above simulation analysis are shown in Table 2 below.

Figure 2022087659000003
Figure 2022087659000003

表２から、本発明例２と本発明例３のいずれの本発明例においても、本発明例１と同様に、比較例よりも十分に首振りが抑えられることがわかった。 From Table 2, it was found that in any of the present invention examples of the present invention example 2 and the present invention example 3, the swinging was sufficiently suppressed as compared with the comparative example, as in the case of the present invention example 1.

１ 鋼部品
２ 開口部
３ 段差部
４ 天板部
５Ａ 湾曲凸部側の縦壁部
５Ｂ 湾曲凹部側の縦壁部
６ フランジ部
Ｌ２１ 鋼部品の段差部の線長
Ｌ２２、Ｌ３１、Ｌ３２、Ｌ３３ 中間部品の段差部の線長
Ｐ１、Ｐ２、Ｐ１１、Ｐ２１ 段差部を構成する線長の端部
Ｒ１、Ｒ２ 断面線
１１ ドロー成形用ダイ
１２ ドロー成形用ホルダー
１３ 鋼板
１４ ドロー成形用パンチ
１５ 中間部品
１６ フォーム成形用ダイ
１７ フォーム成形用パッド
１８ フォーム成形用パンチ 1 Steel parts 2 Opening 3 Steps 4 Top plate 5A Vertical wall on the curved convex side 5B Vertical wall on the curved concave side 6 Flange L21 Line length of the step on the steel parts L22, L31, L32, L33 Intermediate Line length of stepped part P1, P2, P11, P21 End of line length constituting stepped part R1, R2 Cross section line 11 Draw forming die 12 Draw forming holder 13 Steel plate 14 Draw forming punch 15 Intermediate part 16 Foam forming die 17 Foam forming pad 18 Foam forming punch

Claims (3)

長手方向に湾曲した形状を有し、該長手方向に垂直な断面の形状が、コの字型またはハット型であり、湾曲凹部側の縦壁部に、開口部に向かって末広がり形状の段差部を有する、鋼部品を製造する方法であって、
成形用材料を用い、長手方向に垂直な断面における段差部の線長が、前記鋼部品と比較したときに、上面視で前記鋼部品と同じであって、断面視で前記鋼部品よりも長い形状を有する、中間部品を製造する第１工程と、
前記中間部品を用い、湾曲凹部側の縦壁部が鋼部品と同じ形状の金型で成形して、前記中間部品の湾曲凹部側の縦壁部の形状を、鋼部品の湾曲凹部側の縦壁部の形状に変形させる第２工程と
を含む、鋼部品の製造方法。 It has a shape curved in the longitudinal direction, and the shape of the cross section perpendicular to the longitudinal direction is U-shaped or hat-shaped. Is a method of manufacturing steel parts, which has
Using a forming material, the line length of the stepped portion in the cross section perpendicular to the longitudinal direction is the same as the steel part in the top view and longer than the steel part in the cross section when compared with the steel part. The first step of manufacturing intermediate parts with a shape,
Using the intermediate part, the vertical wall portion on the curved concave portion side is molded with a mold having the same shape as the steel part, and the shape of the vertical wall portion on the curved concave portion side of the intermediate part is changed to the vertical wall portion on the curved concave portion side of the steel part. A method for manufacturing a steel part, which comprises a second step of transforming the shape of a wall portion. 前記中間部品の長手方向に垂直な断面における段差部の線長は、断面視で、前記鋼部品の長手方向に垂直な断面における段差部の線長の１．００倍超、１．１０倍以下の長さである、請求項１に記載の鋼部品の製造方法。 The line length of the stepped portion in the cross section perpendicular to the longitudinal direction of the intermediate part is more than 1.00 times and 1.10 times or less of the line length of the stepped portion in the cross section perpendicular to the longitudinal direction of the steel part. The method for manufacturing a steel part according to claim 1, which is the length of the above. 前記鋼部品を構成する鋼板の引張強さは、９８０ＭＰａ以上である、請求項１または２に記載の鋼部品の製造方法。 The method for manufacturing a steel part according to claim 1 or 2, wherein the tensile strength of the steel plate constituting the steel part is 980 MPa or more.
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WO2024070061A1 (en) * 2022-09-28 2024-04-04 Ｊｆｅスチール株式会社 Method for manufacturing press-formed product
JP7476935B2 (en) 2022-09-28 2024-05-01 Ｊｆｅスチール株式会社 Manufacturing method of press-molded products

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