JP2623373B2 - High BH processing metal plate with St-St resistance - Google Patents
High BH processing metal plate with St-St resistanceInfo
- Publication number
- JP2623373B2 JP2623373B2 JP1257891A JP1257891A JP2623373B2 JP 2623373 B2 JP2623373 B2 JP 2623373B2 JP 1257891 A JP1257891 A JP 1257891A JP 1257891 A JP1257891 A JP 1257891A JP 2623373 B2 JP2623373 B2 JP 2623373B2
- Authority
- JP
- Japan
- Prior art keywords
- layer material
- outer layer
- inner layer
- strength
- property
- 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.)
- Expired - Fee Related
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Description
【０００１】[0001]
【産業上の利用分野】本発明は高いＢＨ性を有するにも
かかわらず、ストレッチャ−ストレインが生じない加工
性に優れた金属板に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal plate having excellent workability, which does not cause stretcher strain despite having a high BH property.
【０００２】[0002]
【従来技術】地球環境問題を含め、省エネルギ−対策は
現在の技術開発の一つの大きな課題である。そのため
に、自動車用鋼板ではこの対策の一環として軽量化がク
ロ−ズアップされており、優れた加工性が要求される外
板もハイテン化が進められている。しかし、耐面歪み性
などを考慮するとプレス加工時に強度が高すぎるのは問
題があり、プレス加工時は軟質で、加工後強度が付加で
きる形が理想的である。この要請を叶える形で開発され
たのがＢＨ性鋼板で、成分およびプロセス条件の調整に
より加工性の良い鋼板に数ｐｐｍの固溶Ｃを残存させ、
塗装時の熱処理により固溶Ｃと転位の相互作用を利用し
て強度上昇を図ったものである。しかし、この固溶Ｃと
転位の相互作用による強度アップには成形性の面から限
界がもうけられている。すなわち、残存する固溶Ｃが多
くなり過ぎると降伏点伸びが顕著に表われ、ストレッチ
ャ−ストレインによる表面性状の劣化が生じ、外板とし
ての使用が不可能になる。従って、現状ではストレッチ
ャ−ストレインが生成しない状態で、しかも、得られる
ＢＨ性の上限は１７０℃で２０分のＢＨ処理で約５ｋｇ
ｆ／ｍｍ2程度である。2. Description of the Related Art Energy saving measures, including global environmental issues, are one of the major issues in current technological development. For this reason, reduction in weight of automotive steel sheets has been promoted as a part of this measure, and the use of high-tensile steel is also being promoted for outer panels that require excellent workability. However, considering the surface distortion resistance and the like, there is a problem that the strength is too high at the time of press working, and it is ideal that the form is soft at the time of press working and can add strength after working. The BH steel sheet was developed to meet this demand, and by adjusting the components and process conditions, several ppm of solid solution C remained in the steel sheet with good workability.
The strength is increased by utilizing the interaction between solid solution C and dislocations by heat treatment during coating. However, there is a limit to the increase in strength due to the interaction between the solid solution C and the dislocation from the viewpoint of moldability. That is, if the amount of the remaining solid solution C becomes too large, the elongation at the yield point becomes remarkable, the surface properties are deteriorated by the stretcher strain, and the use as an outer plate becomes impossible. Therefore, at present, the stretcher strain is not generated, and the upper limit of the obtained BH property is about 5 kg by BH treatment at 170 ° C. for 20 minutes.
f / mm 2 .
【０００３】また、ＢＨ性鋼板に関しては特開昭５９−
３８３３７号、特開昭５９−３１８２７号、特開昭６１
−２６７５７号、特開昭６２−７８２２号、特開昭６２
−１０９９２７号、特開平１−１１９２４号公報などの
ほかにも多くの発明が開示されており、固溶Ｃばかれで
なく固溶Ｎを利用したＢＨ性鋼板（特開昭６３−９６２
４８号公報など）も紹介されているが、 ストレッチャ
−ストレインの生成を抑え、かつ高いＢＨ性を保証する
技術は未だ発明されていない。[0003] Further, regarding BH steel sheets,
38337, JP-A-59-31827, JP-A-61
No. 26957, JP-A-62-28222, JP-A-62-7822
A number of inventions have been disclosed in addition to JP-A-10-99927 and JP-A-1-119924, and a BH steel sheet utilizing solid-solution N instead of solid-solution C (see JP-A-63-962).
No. 48, etc.), but a technique for suppressing the generation of stretcher strain and guaranteeing a high BH property has not yet been invented.
【０００４】[0004]
【発明が解決しようとする課題】本発明はストレッチャ
−ストレインの生成を抑え、５ｋｇｆ／ｍｍ2以上のＢ
Ｈ性を持つ加工用金属板を提供することを目的としてな
された。SUMMARY OF THE INVENTION The present invention suppresses the formation of a stretcher strain, and suppresses the generation of B of 5 kgf / mm 2 or more.
It was made for the purpose of providing a metal plate for processing having H property.
【０００５】[0005]
【課題を解決するための手段】本発明の要旨とするとこ
ろは、２種の材料からなる３層構造を有する金属板にお
いて、外層材の降伏点伸びが０．０５％以下、内層材の
ＢＨ性が少なくとも、５ｋｇｆ／ｍｍ2以上、および外
層材の強度と内層材の強度の比Ｘが１．２以上で、かつ
外層材の板厚の総和ｔ1と内層材の板厚ｔ2の比とＸの関
係が、下記の（１）、（２）の条件式を満足することを
特徴とする耐Ｓｔ−Ｓｔ性を持つ高ＢＨ性加工用金属
板。 Ｘ： １．２＜Ｘ＜２．５の場合、 −０．０５Ｘ＋０．１７５＜ｔ1／ｔ2＜−０．０５Ｘ＋０．３７５ …（１） Ｘ≧２．５の場合、 ０．０５＜ｔ1／ｔ2＜０．２５ …（２） にある。SUMMARY OF THE INVENTION The gist of the present invention is to provide a metal plate having a three-layer structure made of two materials, in which the outer layer material has a yield point elongation of 0.05% or less and the inner layer material has a BH of less than 0.05%. At least 5 kgf / mm 2 , the ratio X of the strength of the outer layer material to the strength of the inner layer material is 1.2 or more, and the ratio of the total thickness t 1 of the outer layer material to the thickness t 2 of the inner layer material. And X satisfying the following conditional expressions (1) and (2): a metal sheet for high BH processing having high St-St resistance. X: When 1.2 <X <2.5, −0.05X + 0.175 <t 1 / t 2 <−0.05X + 0.375 (1) When X ≧ 2.5, 0.05 <t 1 / t 2 <0.25 (2)
【０００６】[0006]
【作用】以下、本発明について詳細に説明する。上記の
課題の基づいて、発明者らは研究を重ねた結果、耐スト
レッチャ−ストレインとＢＨ性の両方の特性を付加する
ためには、異なった特性を持つ板の複層構造によって達
成できることを見出した。そこで、この知見に基づき、
本発明の構成並びにその限定理由をのべる。先ず、本発
明における外層材の材質特性の限界条件であるが、外層
材の降伏点伸びが０．０５％を超すと後述する外層材と
内層材の強度比と板厚比をどのように変えても、ストレ
ッチャ−ストレインの生成を抑えることができない。ま
た、内層材の材質特性についてであるが、内層材のＢＨ
性が５ｋｇｆ／ｍｍ2以下であるなら、本発明材のよう
な複層構造にしなくても、従来のＢＨ性鋼板によって
も、耐ストレッチャ−ストレインとＢＨ性の両方の特性
を得ることができる。従って、本発明材の狙いはＢＨ性
が５ｋｇｆ／ｍｍ2以上、好ましくは１０ｋｇｆ／ｍｍ2
以上を有し、かつストレッチャ−ストレインが生成しな
いことにあるので、内層材のＢＨ性は少なくとも５ｋｇ
ｆ／ｍｍ2以上であることが必要である。なお、上記各
層の材質については、研削などにより一方の層の材料を
取り除き引張試験を行なって調べることができる。Hereinafter, the present invention will be described in detail. Based on the above-mentioned problems, the present inventors have made repeated studies and found that in order to add both the stretcher strain resistance and the BH property, it can be achieved by a multilayer structure of plates having different properties. Was. Therefore, based on this knowledge,
The configuration of the present invention and the reasons for the limitation will be described. First, the critical condition of the material properties of the outer layer material in the present invention is as follows. When the yield point elongation of the outer layer material exceeds 0.05%, how the strength ratio and the thickness ratio of the outer layer material and the inner layer material described later are changed. However, generation of stretcher strain cannot be suppressed. Regarding the material properties of the inner layer material, the BH
If the hardness is 5 kgf / mm 2 or less, both the stretcher strain resistance and the BH property can be obtained by the conventional BH steel sheet without using the multilayer structure as in the material of the present invention. Therefore, the aim of the material of the present invention is to achieve a BH property of 5 kgf / mm 2 or more, preferably 10 kgf / mm 2.
The BH property of the inner layer material is at least 5 kg.
f / mm 2 or more. The material of each layer can be checked by removing the material of one layer by grinding or the like and conducting a tensile test.
【０００７】次に、複層構造に関する限定条件について
述べる。３層構造を有する板において、外層材の強度が
内層材より少なくとも１．２倍以上有り、かつ外層材と
内層材の板厚比ｔ1／ｔ2については、外層材と内層材の
強度比Ｘが１．２＜Ｘ＜２．５の範囲で、−０．０５Ｘ
＋０．１７５＜ｔ1／ｔ2＜−０．０５Ｘ＋０．３７５の
条件式を、そしてＸが２．５以上では０．０５＜ｔ1／
ｔ2＜０．２５の条件式を満足しなければならない。そ
の理由は、外層材の強度が内層材より少なくとも１．２
倍以上でないと、たとえ条件式（１）、（２）を満足し
てもストレッチャ−ストレインの生成を抑えることがで
きないためである。このことは、外層材の強度が内層材
よりある程度大きくないと内層材に生じようとする降伏
点伸びを効果的に抑えることができないことを示唆して
いる。また、条件式（１）、（２）の下限は、たとえ強
度比が１．２以上でも外層の板厚が少なくとも、この下
限の条件より大きくないとストレッチャ−ストレインの
生成を抑えることができないことにより限定される。一
方、上限は加工性とＢＨ性の観点から限定するもので、
板厚比が上限値より大きくなると加工性が損なわれるば
かりでなく、十分なＢＨ性が得られなくなる。Next, the limiting conditions for the multilayer structure will be described. In a plate having a three-layer structure, the strength of the outer layer material is at least 1.2 times or more that of the inner layer material, and the thickness ratio t 1 / t 2 between the outer layer material and the inner layer material is the strength ratio of the outer layer material to the inner layer material. X is -0.05X when 1.2 <X <2.5.
+0.175 <t 1 / t 2 <−0.05X + 0.375, and when X is 2.5 or more, 0.05 <t 1 /
The conditional expression t 2 <0.25 must be satisfied. The reason is that the strength of the outer layer material is at least 1.2
If it is not more than twice, even if conditional expressions (1) and (2) are satisfied, it is not possible to suppress the generation of the stretcher strain. This suggests that if the strength of the outer layer material is not higher than the inner layer material to some extent, the yield point elongation to be generated in the inner layer material cannot be effectively suppressed. Further, the lower limit of the conditional expressions (1) and (2) is that even if the strength ratio is 1.2 or more, the thickness of the outer layer cannot be suppressed unless the thickness of the outer layer is at least larger than the lower limit. Is limited by On the other hand, the upper limit is limited from the viewpoint of workability and BH property,
When the thickness ratio is larger than the upper limit, not only the workability is impaired, but also a sufficient BH property cannot be obtained.
【０００８】本発明材の外層材と内層材の具体例は実施
例にも示すが、外層材に降伏点伸びを示さない複合組織
高張力鋼（Ｄｕａｌ Ｐｈａｓｅ鋼）や高バ−リング鋼
などを用い、内層材に固溶Ｃ、Ｎを残存させた軟質鋼を
用いる組み合せや、外層材に固溶Ｃ、ＮをＴｉ，Ｎｂな
どの炭窒化物生成元素で固着したＩＦ鋼を用い、内層材
にＭｇを添加した高いＢＨ性を示すＡｌ合金を用いる組
み合せ、あるいは耐食性をも付加した外層にステンレ
ス、内層に固溶Ｃ、Ｎを残存させた軟質鋼を用いる組み
合せなどが自動車用薄板として適用できる。また、この
複層構造の製造方法としては、 圧延圧着法、鋳込みに
よる複層製造法、爆着法などいろいろな方法があるが、
本発明材においては複層の製造法に限定されるものでは
ない。[0008] Specific examples of the outer layer material and the inner layer material of the material of the present invention are also shown in Examples, but a high-strength composite structure steel (Dual Phase steel) or a high-burring steel, which does not exhibit a yield point elongation in the outer layer material. A combination of soft steel in which solid solution C and N are left in the inner layer material, and an IF steel in which solid solution C and N are fixed to the outer layer material by carbonitride forming elements such as Ti and Nb. A combination using an Al alloy exhibiting high BH with Mg added thereto, or a combination using a stainless steel in the outer layer also having corrosion resistance and a soft steel in which solid solution C and N are left in the inner layer, etc. can be applied as a thin plate for an automobile. . There are various methods for producing this multilayer structure, such as a rolling compression bonding method, a multilayer production method by casting, and an explosion method.
The material of the present invention is not limited to the method for producing a multilayer.
【０００９】[0009]
【実施例】表１に示す成分の材料を組み合わせて、３層
から成る複層構造の板を製造した後、その板の機械性質
および、片方の層を研削した後の外層材の降伏点伸びと
内層材のＢＨ性を表２に示す。また、同表に外内層の強
度比と板厚分率比も示す。全板厚は０．８ｍｍである。
ストレッチャ−ストレイン（Ｓｔ−Ｓｔ）の生成の有無
は引張試験時に目視で判断した。ＢＨ性は１７０℃で２
０分の熱処理前後の降伏点の差によって表した。実験番
号１、２、４、５、８、９、１１、１３は本発明の範囲
内でストレッチャ−ストレインの生成なしの高いＢＨ性
を示す。実験番号３、１２は条件式（１）あるいは
（２）を満足出来ないために、ストレッチャ−ストレイ
ンが生成した。実験番号６、７は外層材と内層材の強度
比Ｘが本発明の必要条件である１．２以下であるために
ストレッチャ−ストレインが表われた。実験番号１０は
内層材のＢＨ性が０のため、複層材もＢＨ性を示さず、
本発明を意図するものでない。実験番号１４は最終焼鈍
の２相域加熱後の冷却速度が小さかったため外層材の組
織がフェライト−パ−ライト組織になり、降伏点伸びが
生成し、ストレッチャ−ストレインが表われた。また、
発明材のうち、実験番号１、２、４、１１、１３は２相
域に加熱後、急冷して、外層材を複合組織にして降伏点
伸びを抑制した。実験番号５、９の外層はＩＦ鋼を用い
て降伏点伸びを抑制した。一方、複層構造の製造方法は
実験番号、１、２、３、１０、１１、１２、１３が電子
ビ−ム溶接、実験番号４、５、６、７、８、１４が鋳込
み複層、そして実験番号９が圧延圧着によったが、これ
らいずれの複層構造の製造方法にも限定されるものでな
く、本発明の範囲を満たすことにより優れた特性が得ら
れる。また、実験番号１３に見られるように材料に組み
合わせによってｒ値が２以上の材料も製造できる。EXAMPLE A plate having a multilayer structure composed of three layers was manufactured by combining the materials of the components shown in Table 1, and the mechanical properties of the plate and the yield point elongation of the outer layer material after grinding one of the layers. Table 2 shows the BH properties of the inner layer material. The table also shows the strength ratio of the outer and inner layers and the plate thickness fraction ratio. The total thickness is 0.8 mm.
The presence or absence of the generation of the stretcher strain (St-St) was visually determined during the tensile test. BH property is 2 at 170 ° C
It was represented by the difference in yield point before and after the 0 minute heat treatment. Experiment Nos. 1, 2, 4, 5, 8, 9, 11, 13 show high BH properties without the formation of stretcher strains within the scope of the present invention. In Experiment Nos. 3 and 12, a stretcher strain was generated because conditional expression (1) or (2) could not be satisfied. In Experiment Nos. 6 and 7, a stretcher strain was shown because the strength ratio X between the outer layer material and the inner layer material was 1.2 or less which is a necessary condition of the present invention. In Experiment No. 10, since the BH property of the inner layer material was 0, the multilayer material also did not show the BH property,
It is not intended for the present invention. In Experiment No. 14, since the cooling rate after heating in the two-phase region in the final annealing was low, the structure of the outer layer material was a ferrite-pearlite structure, yield point elongation was generated, and a stretcher strain was exhibited. Also,
Among the inventive materials, in Experiment Nos. 1, 2, 4, 11, and 13, after heating to the two-phase region, the material was rapidly cooled to make the outer layer material a composite structure, and the yield point elongation was suppressed. The outer layers of Experiment Nos. 5 and 9 suppressed yield point elongation using IF steel. On the other hand, the manufacturing method of the multilayer structure is as follows: Experiment Nos. 1, 2, 3, 10, 11, 12, 13 are electron beam welding, and Experiment Nos. 4, 5, 6, 7, 8, 14 are casting multilayers. Although Experiment No. 9 was based on rolling and pressure bonding, the present invention is not limited to any of these methods for producing a multilayer structure, and excellent characteristics can be obtained by satisfying the scope of the present invention. Further, as shown in Experiment No. 13, a material having an r value of 2 or more can be produced by combining the materials.
【００１０】[0010]
【表１】 [Table 1]
【００１１】[0011]
【表２】 [Table 2]
【００１２】[0012]
【表２−１】〔表２のつづき〕 [Table 2-1] [Continuation of Table 2]
【００１３】[0013]
【発明の効果】以上述べたように、本発明はいままで不
可能とされていたストレッチャ−ストレインの生成なし
で、しかも５ｋｇｆ／ｍｍ2以上のＢＨ性を付与できる
技術を提供するもので、耐デント性の顕著な向上が得ら
れ、板厚減少による軽量化が図られ、自動車用の外板な
どに広く使用でき、産業上極めて大きな効果が期待され
る。As described above, the present invention provides a technique capable of imparting a BH property of 5 kgf / mm 2 or more without producing a stretcher strain, which has been impossible so far. A remarkable improvement in the dent property is obtained, the weight is reduced by reducing the thickness, and it can be widely used for an outer panel of an automobile, etc., and an extremely large effect is expected in industry.
Claims (1)
属板において、外層材の降伏点伸びが０．０５％以下、
内層材のＢＨ性が少なくとも５ｋｇｆ／ｍｍ2以上、お
よび外層材の強度と内層材の強度の比Ｘが１．２以上
で、かつ外層材の板厚の総和ｔ1と内層材の板厚ｔ2の比
とＸの関係が、 下記の（１）、（２）の条件式を満足
することを特徴とする耐Ｓｔ−Ｓｔ性を持つ高ＢＨ性加
工用金属板。 Ｘ： １．２＜Ｘ＜２．５の場合、 −０．０５Ｘ＋０．１７５＜ｔ1／ｔ2＜−０．０５Ｘ＋０．３７５ …（１） Ｘ≧２．５の場合、 ０．０５＜ｔ1／ｔ2＜０．２５ …（２）1. A metal plate having a three-layer structure made of two kinds of materials, wherein the outer layer material has a yield point elongation of 0.05% or less;
The BH property of the inner layer material is at least 5 kgf / mm 2 or more, the ratio X of the strength of the outer layer material to the strength of the inner layer material is 1.2 or more, and the total thickness t 1 of the outer layer material and the thickness t of the inner layer material A metal sheet for high BH processing having high St-St resistance, wherein the relation between the ratio of 2 and X satisfies the following conditional expressions (1) and (2). X: When 1.2 <X <2.5, −0.05X + 0.175 <t 1 / t 2 <−0.05X + 0.375 (1) When X ≧ 2.5, 0.05 <t 1 / t 2 <0.25 (2)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1257891A JP2623373B2 (en) | 1991-01-11 | 1991-01-11 | High BH processing metal plate with St-St resistance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1257891A JP2623373B2 (en) | 1991-01-11 | 1991-01-11 | High BH processing metal plate with St-St resistance |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04241939A JPH04241939A (en) | 1992-08-28 |
| JP2623373B2 true JP2623373B2 (en) | 1997-06-25 |
Family
ID=11809242
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1257891A Expired - Fee Related JP2623373B2 (en) | 1991-01-11 | 1991-01-11 | High BH processing metal plate with St-St resistance |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2623373B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104647823A (en) * | 2013-11-25 | 2015-05-27 | 中国兵器工业第五二研究所 | Shock-resistant energy-absorbing material and preparation method thereof |
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1991
- 1991-01-11 JP JP1257891A patent/JP2623373B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104647823A (en) * | 2013-11-25 | 2015-05-27 | 中国兵器工业第五二研究所 | Shock-resistant energy-absorbing material and preparation method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04241939A (en) | 1992-08-28 |
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