JP2002060888A - Steel sheet for blanking - Google Patents
Steel sheet for blankingInfo
- Publication number
- JP2002060888A JP2002060888A JP2000247244A JP2000247244A JP2002060888A JP 2002060888 A JP2002060888 A JP 2002060888A JP 2000247244 A JP2000247244 A JP 2000247244A JP 2000247244 A JP2000247244 A JP 2000247244A JP 2002060888 A JP2002060888 A JP 2002060888A
- Authority
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- Japan
- Prior art keywords
- mass
- steel sheet
- less
- punching
- punched
- 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.)
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- Heat Treatment Of Sheet Steel (AREA)
Abstract
Description
【0001】[0001]
【産業上の利用分野】本発明は、熱処理により高強度に
調質可能で疲労特性にも優れた打抜き加工用鋼板に関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a punching steel sheet which can be tempered to a high strength by heat treatment and has excellent fatigue characteristics.
【0002】[0002]
【従来の技術】打抜き加工で素材を部品形状に成形した
後、熱処理によって調質した材料を各種機械部品等の部
材に使用することがある。この種の部品には、高硬度,
高強度,高靭性,高疲労強度,耐摩耗性等の機械的特性
が要求される。疲労特性や耐摩耗性は一般的に硬さや強
度を高めることにより改善されるが、硬さや強度の上昇
に伴って靭性が低下するため、特に切欠き感受性の上昇
に起因した問題が顕在化する。また、打抜き後の部品端
面に破断面が通常露出しているが、破断面に存在する微
小クラック等の表面欠陥を完全に除去することなく製品
として使用されている。打抜き後の素材端面に存在する
表面欠陥は、切欠き,初期亀裂等として作用し、部品の
切欠き感受性を上昇させる原因になる。特に、高強度化
を図るため、調質硬さを45HRC以上又は引張強さを
1500MPa以上に高めると,切欠き感受性が一層高
くなり、疲労強度及び靭性が低下する。しかし、工業的
な大量生産ラインで打抜き面性状を保証することは非常
に困難である。2. Description of the Related Art In some cases, after a material is formed into a part shape by punching, a material heat-treated by heat treatment is used for members such as various mechanical parts. Parts of this type have high hardness,
Mechanical properties such as high strength, high toughness, high fatigue strength, and wear resistance are required. Fatigue properties and abrasion resistance are generally improved by increasing hardness and strength, but since toughness decreases with increasing hardness and strength, problems due to increased notch sensitivity become apparent. . Further, although a fracture surface is normally exposed on the end face of the part after punching, it is used as a product without completely removing surface defects such as minute cracks existing in the fracture surface. The surface defect existing on the end face of the blank after punching acts as a notch, an initial crack, or the like, and increases the notch sensitivity of the component. In particular, when the temper hardness is increased to 45 HRC or more or the tensile strength is increased to 1500 MPa or more to increase the strength, the notch sensitivity is further increased, and the fatigue strength and toughness are reduced. However, it is very difficult to guarantee the punched surface properties in an industrial mass production line.
【0003】打抜き面性状の影響を小さくするため、打
抜き面にコイニング加工を施し、加工硬化や圧縮残留応
力によって疲労特性を改善する方法が知られている(特
開平2−147129号公報,特開平6−57325号
公報)。しかし、コイニング加工された部品を熱処理す
ると、特性改善効果が著しく低減する。また、機械加工
で部品を作製する方法や打抜き部品の端面を機械加工に
よって切削する方法等も知られているが、何れも生産性
が低く、また複雑形状の部品に適用できない。打抜き端
面の欠陥を研磨によって除去することも可能であるが、
時間及びコストを要し、欠陥の完全な除去は工業的観点
から困難である。[0003] In order to reduce the influence of the punched surface properties, a method is known in which the stamped surface is subjected to coining to improve the fatigue characteristics by work hardening and compressive residual stress (Japanese Patent Laid-Open Nos. 2-147129 and 2-147129). 6-57325). However, when the coined part is heat-treated, the effect of improving characteristics is significantly reduced. In addition, a method of manufacturing a part by machining, a method of cutting an end face of a punched part by machining, and the like are known, but none of them has low productivity and cannot be applied to a part having a complicated shape. Although it is possible to remove defects on the punched end face by polishing,
Time and cost are required, and complete removal of defects is difficult from an industrial point of view.
【0004】[0004]
【発明が解決しようとする課題】打抜き面を構成する破
断面及び剪断面のうち、破断面は疲労破壊の起点にな
る。そこで、剪断面率を高めることによって打抜き面性
状を改善する方法が一部で採用されている(特開平8−
337843号公報)。剪断面率は精密打抜きにより1
00%にまで高められるが、精密打抜き性の改善には軟
質化した材料の使用が必要になる(特公平5−1476
4号公報)。しかし、精密打抜きは、通常の打抜きに比
較して生産性及び歩留が低いため、採算上から安価な部
品の製造に適用できない場合が多い。軟質化が剪断面率
の上昇に及ぼす影響は通常の打抜きでも同様に生じる
が、軟質化した材料ではかえりが大きく、打抜かれた部
品の平坦度が低くなる。この点、軟質化による打抜き性
の改善には限界がある。Among the fractured surfaces and sheared surfaces constituting the punched surface, the fractured surface is a starting point of fatigue failure. Therefore, a method of improving the punched surface properties by increasing the shearing surface ratio has been partially adopted (Japanese Patent Laid-Open No. Hei 8-
No. 337843). Shear ratio is 1 by precision punching
However, in order to improve the precision punching property, it is necessary to use a softened material (Japanese Patent Publication No. 5-1476).
No. 4). However, precision punching has low productivity and yield as compared with normal punching, and therefore cannot be applied to the production of inexpensive parts from the viewpoint of profitability. The effect of the softening on the increase in the shear area also occurs in the case of ordinary punching, but the softened material has a large burr and the flatness of the punched part is low. In this respect, there is a limit to the improvement of the punching property due to softening.
【0005】切欠き感受性の改善には、部品の強度低下
も有効である。しかし、強度低下に伴って疲労強度も低
下するので、各種機械部品に要求される特性が得られな
い。このように、打抜き部品の強度を確保しながら疲労
特性を向上させることは難しく、なかでも45HRC以
上の硬さ水準で打抜き部品の疲労特性を改善することは
極めて困難である。更に、打抜き部品用の鋼板として
は、打抜き後に熱処理を施される部品もあることから、
焼入れ性や熱処理後の靭性等に優れていることも必要で
ある。[0005] To improve the notch sensitivity, it is also effective to reduce the strength of parts. However, since the fatigue strength decreases with the decrease in strength, the characteristics required for various mechanical parts cannot be obtained. As described above, it is difficult to improve the fatigue properties while securing the strength of the stamped parts, and particularly, it is extremely difficult to improve the fatigue properties of the stamped parts at a hardness level of 45 HRC or more. Furthermore, as steel sheets for stamped parts, some parts are subjected to heat treatment after stamping,
It is also necessary to have excellent hardenability and toughness after heat treatment.
【0006】[0006]
【課題を解決するための手段】本発明は、このような問
題を解消すべく案出されたものであり、鋼板の打抜き加
工で生じた破断面性状を管理することにより、優れた疲
労特性を呈する打抜き加工用鋼板を提供することを目的
とする。DISCLOSURE OF THE INVENTION The present invention has been devised in order to solve such a problem, and has excellent fatigue characteristics by controlling the fracture surface characteristics generated by punching a steel sheet. An object of the present invention is to provide a steel sheet for punching.
【0007】本発明の打抜き加工用鋼板は、その目的を
達成するため、C:0.3〜0.8質量%,Si:3.
0質量%以下,Mn:1.5質量%以下,Cr:2.0
質量%以下,Cu:0.5質量%以下,N:0.000
5〜0.02質量%,O:0.0005〜0.01質量
%,P:0.02質量%以下,S:0.01質量%以
下,酸可溶Al:0.01〜0.10質量%を含み、残
部が実質的にFeの組成をもち、打抜き加工後に最大応
力が作用する位置の打抜き面における破断面粗さがRy
100μm以下、破断面の二次剪断比率が0となること
を特徴とする。In order to achieve the object, the steel sheet for stamping of the present invention has a C content of 0.3 to 0.8% by mass and a Si content of 3.%.
0 mass% or less, Mn: 1.5 mass% or less, Cr: 2.0
% By mass, Cu: 0.5% by mass or less, N: 0.000
5 to 0.02 mass%, O: 0.0005 to 0.01 mass%, P: 0.02 mass% or less, S: 0.01 mass% or less, acid-soluble Al: 0.01 to 0.10 Mass%, and the balance substantially has the composition of Fe, and the fracture surface roughness of the punched surface at the position where the maximum stress acts after the punching is Ry.
The secondary shear ratio of the fractured surface is 0 μm or less, and is characterized by being 0.
【0008】使用する鋼板は、更にMo:0.1〜2.
0質量%,Ni:0.1〜3.0質量%,V:0.01
〜0.5質量%,Ti:0.01〜0.1質量%,N
b:0.01〜0.2質量%,B:0.0005〜0.
01質量%の1種又は2種以上を含むことができ、ビッ
カース硬さを200〜400HVの範囲に調整すること
が好ましい。また、炭化物の球状化率90%以上で平均
粒径0.6μm以下の球状化炭化物が分散したフェライ
ト+炭化物の組織をもつ鋼板を使用することにより、良
好な打抜き面をもつ打抜き加工用鋼板が得られる。[0008] The steel sheet used is Mo: 0.1 to 2.
0% by mass, Ni: 0.1 to 3.0% by mass, V: 0.01
To 0.5% by mass, Ti: 0.01 to 0.1% by mass, N
b: 0.01 to 0.2% by mass, B: 0.0005 to 0.
One or two or more of the components may be contained in an amount of 01% by mass, and the Vickers hardness is preferably adjusted to a range of 200 to 400 HV. Further, by using a steel sheet having a ferrite + carbide structure in which a spheroidized carbide having a spheroidization ratio of carbide of 90% or more and an average particle diameter of 0.6 μm or less is dispersed, a steel sheet for punching having a good punched surface can be obtained. can get.
【0009】[0009]
【作用】本発明者等は、打抜き部品が使用過程で疲労破
壊する場合、破壊の起点となる位置を詳細に調査した。
その結果,疲労破壊の起点は主に打抜き面の破断面にあ
ることが判った。一般に打抜き面の破断面は、板表面や
剪断面の部分に比べて凹凸が大きいため応力集中の程度
が大きくなり、亀裂の起点になりやすいと考えられる。
したがって、破断面の粗さを抑えることにより亀裂の発
生が抑えられることが予想される。このような前提に立
って,破断面粗さと疲労特性との関係を調査したとこ
ろ,破断面の粗さの指標として、JIS B0601に
規定されている表面粗さRyと疲労特性との間に良好な
相関関係があることを見出した。具体的には、図1に示
すようにRyが100μmを超えると、時間強度(破断
サイクル105回を得られる強度)が大きく劣化する。
Ryは、粗さ曲線における最大高低差であり、Ryが大
きい部分は最も応力が集中しやすく亀裂の起点になりや
すいと考えられる。The present inventors have investigated in detail the starting point of the fracture when the punched part undergoes fatigue failure during use.
As a result, it was found that the starting point of fatigue fracture was mainly at the fracture surface of the punched surface. Generally, the fracture surface of the punched surface is considered to be more likely to be a starting point of a crack because the unevenness is larger than that of the plate surface or the shear surface, so that the stress concentration is increased.
Therefore, it is expected that the generation of cracks will be suppressed by suppressing the roughness of the fractured surface. Based on this premise, the relationship between the fracture surface roughness and the fatigue characteristics was investigated. As an index of the fracture surface roughness, the relationship between the surface roughness Ry defined in JIS B0601 and the fatigue characteristics was good. We found that there was a great correlation. Specifically, when the Ry as shown in FIG. 1 exceeds 100 [mu] m, (intensity obtained at break cycles 10 5 times) times the strength greatly deteriorates.
Ry is the maximum height difference in the roughness curve, and it is considered that the portion where Ry is large is most likely to concentrate stress and becomes the starting point of a crack.
【0010】通常の打抜き加工では、破断面の他に二次
剪断面が打抜き面に生じやすい。二次剪断面が生じる
と、破断面と二次剪断面との間に段差がつき、境界部が
切欠き形状になる。打抜き面に亀裂が発生する場合、切
欠きの底に相当する二次剪断面/破断面の境界が起点に
なる。したがって、二次剪断面が生じない条件下で打抜
き加工することにより、亀裂の発生が抑えられ、疲労特
性の向上が予測される。打抜き面に生じる破断面の粗さ
や二次剪断面の発生は、打抜きクリアランスや打抜き素
材の硬さや組織の影響を受ける。したがって、打抜きク
リアランス,素材硬さ及び組織を適正に調整することに
より、破断面の粗さを最大高低差Ryで100μm以下
にすると共に、二次剪断面のない打抜き面が得られる。[0010] In ordinary punching, a secondary shear surface is likely to be formed on the punched surface in addition to the fractured surface. When the secondary shear surface occurs, a step is formed between the fracture surface and the secondary shear surface, and the boundary portion has a notched shape. When a crack is generated in the punched surface, the boundary between the secondary shear surface and the fracture surface corresponding to the bottom of the notch becomes the starting point. Therefore, by performing the punching process under the condition that the secondary shear surface does not occur, the occurrence of cracks is suppressed, and the improvement of the fatigue properties is expected. The generation of the fracture surface roughness and secondary shear surface generated on the punched surface is affected by the punch clearance, the hardness of the punched material, and the structure. Therefore, by appropriately adjusting the punching clearance, the hardness of the material, and the structure, the roughness of the fractured surface can be reduced to a maximum height difference Ry of 100 μm or less and a punched surface having no secondary shear surface can be obtained.
【0011】打抜き加工で生じた打抜き面のどの部分で
も、破断面の最大高低差Ryを100μm以下にして二
次剪断面が生じないようにすることが好ましい。しか
し、打抜き素材の種類,部品形状,金型の状態等によっ
ては、二次剪断面がなく打抜き面の全ての位置で最大高
低差Ryを100μm以下にすることが困難な場合もあ
る。このような場合、打抜き加工後の特定位置における
打抜き面を所定の面性状にすることにより、所期の効果
が得られる。具体的には、打抜き加工部品に疲労荷重が
作用するとき、最大応力が作用する位置の打抜き面にお
いて、二次剪断面がなく且つ破断面の最大高低差Ryを
100μm以下に規制することにより、亀裂の発生が抑
制され、疲労特性が向上する。最大応力が作用する位置
は、打抜き加工部品の形状及び荷重の印加方向から材料
力学的に特定できる。たとえば、部品に引張り疲労が付
与される場合、切欠き部の底,曲率が小さいRの底等が
引張り方向においての最大応力集中部となる。It is preferable that the maximum height difference Ry of the fractured surface be 100 μm or less at any part of the punched surface generated by the punching process so that a secondary shear surface does not occur. However, depending on the type of the blank material, the shape of the part, the state of the mold, and the like, it may be difficult to reduce the maximum height difference Ry to 100 μm or less at all positions on the blanked surface without a secondary shear plane. In such a case, the desired effect can be obtained by making the punched surface at a specific position after the punching process have a predetermined surface property. Specifically, when a fatigue load is applied to a stamped part, by restricting the maximum height difference Ry of the fractured surface to 100 μm or less without a secondary shear surface on the punched surface at the position where the maximum stress is applied, Crack generation is suppressed, and fatigue characteristics are improved. The position where the maximum stress acts can be specified mechanically from the shape of the stamped part and the direction in which the load is applied. For example, when tensile fatigue is imparted to a component, the bottom of the notch, the bottom of R having a small curvature, and the like become the maximum stress concentration portion in the tensile direction.
【0012】軟質の素材では、打抜き加工時に破断面近
傍で局部的な変形量が増大するため、打抜き面が粗くな
ると共に二次剪断面が生じやすくなる。その結果、打抜
き加工部品の疲労特性が劣化する。この傾向は、200
HV未満の硬さで顕著に現れる。低い硬さは、打抜き加
工時のかえりを大きくし、打抜き加工部品の形状不良を
引き起こす原因にもなる。しかし、400HVを超える
硬質の素材では、打抜き金型への負荷が大きくなり、金
型寿命が損なわれる。素材の硬さは、炭化物形態により
影響され、焼きなまし条件や冷間圧延条件によって調整
できる。In the case of a soft material, the amount of local deformation increases near the fractured surface during the punching process, so that the punched surface becomes rough and a secondary shear surface is likely to occur. As a result, the fatigue characteristics of the stamped part are degraded. This trend is 200
Appears remarkably at hardness less than HV. The low hardness increases burrs at the time of punching, and also causes a shape defect of the punched part. However, with a hard material exceeding 400 HV, the load on the punching die increases, and the life of the die is impaired. The hardness of the material is affected by the form of the carbide and can be adjusted by annealing conditions or cold rolling conditions.
【0013】炭化物形態は、打抜き面性状、ひいては疲
労特性にも影響を及ぼす。すなわち、打抜き加工時に素
材が局部的に塑性変形するが、このときの塑性変形に引
きずられた炭化物の痕跡が破断面近傍に残る。痕跡の程
度は炭化物の大きさによって異なり、粗大な炭化物があ
る組織では粗大なボイドやボイドが集合・成長した微小
クラックが発生する。この点、鋼材に分散している炭化
物を球状化すると共に、球状化炭化物のサイズを規制す
ることにより、疲労破壊の起点になる微小クラック及び
切欠きが最小限に抑えられる。このようなことから、本
発明では、球状化率が90%以上で球状化炭化物の平均
粒径が0.6μm以下に規制されたフェライト+炭化物
組織の鋼板を使用している。[0013] The carbide form also affects the punched surface properties and, consequently, the fatigue properties. That is, the material is locally plastically deformed during the punching process, but traces of carbides dragged by the plastic deformation at this time remain near the fracture surface. The extent of the trace differs depending on the size of the carbide, and in a structure having coarse carbides, coarse voids and minute cracks in which the voids are aggregated and grown are generated. In this regard, by spheroidizing the carbide dispersed in the steel material and controlling the size of the spheroidized carbide, micro cracks and notches, which are the starting points of fatigue fracture, can be minimized. For this reason, in the present invention, a steel sheet having a ferrite + carbide structure in which the spheroidization rate is 90% or more and the average particle size of the spheroidized carbide is regulated to 0.6 μm or less is used.
【0014】炭化物の球状化率及び球状化炭化物の平均
粒径が打抜き加工性に及ぼす影響は、本発明者等がすで
に特願平11−233598号で紹介したところである
が、更に打抜き面性状を規制することにより前述したよ
うに疲労特性が改善される。本発明で使用する鋼板は、
炭化物がフェライトマトリックスに分散した組織をもっ
ているが、パーライト,ベイナイト等を含んでいてもよ
い。フェライトマトリックスに分散している炭化物の形
態は、打抜き面の破断面性状に大きな影響を及ぼす。炭
化物の球状化率を小さくすると球状化炭化物が微細にな
る傾向にあるが、球状化率の低下に伴って炭化物分布が
不均一化し、部品間での打抜き面性状にバラツキが大き
くなると共に、金型寿命も短くなる。逆に大きな球状化
率では粗大な炭化物が分散するようになり、打抜き面に
微小クラックやボイドが発生しやすくなることを示し
た。The effects of the spheroidization rate of the carbide and the average particle size of the spheroidized carbide on the punching workability have already been introduced by the present inventors in Japanese Patent Application No. 11-233598. The regulation improves the fatigue characteristics as described above. The steel sheet used in the present invention is
It has a structure in which carbides are dispersed in a ferrite matrix, but may contain pearlite, bainite, and the like. The form of the carbide dispersed in the ferrite matrix has a great effect on the fracture surface properties of the punched surface. When the spheroidization rate of the carbide is reduced, the spheroidized carbide tends to become finer.However, as the spheroidization rate decreases, the distribution of carbides becomes uneven, and the variation in the punched surface properties between parts increases, and Mold life is also shortened. Conversely, when the spheroidization ratio is large, coarse carbides are dispersed, which indicates that minute cracks and voids are easily generated on the punched surface.
【0015】今回、本発明者等の調査・研究の結果か
ら、炭化物の球状化率を90%以上,球状化炭化物の平
均粒径を0.6μm以下に規制するとき、破断面の粗面
化が抑えられ、疲労特性に優れた打抜き加工部材が得ら
れることが判った。なお、本件明細書では、鋼板断面の
観察視野内である炭化物の最大長さpとそれに直交する
方向の最大ながさqの比(p/q)が3未満である場
合、当該炭化物を球状化した炭化物とし、全炭化物に対
する球状化炭化物の個数割合を球状化率と定義した。球
状化率が90%を下回ると、打抜き面に二次剪断面が生
じやすくなり、疲労特性が劣化する。更に、個々の球状
化炭化物の面積から円相当径を算出し、測定した全球状
炭化物の個数で円相当径の合計を除した値を球状化炭化
物の平均粒径と定義した。球状化炭化物の平均粒径が
0.6μmを越えると、破断面近傍の打抜き面に生じる
微小クラックやボイドの寸法が大きくなり、破断面が粗
面化し、疲労特性が劣化する。粗大な球状化炭化物は、
熱処理時に固溶することなく残存し、熱処理後の靭性を
低下させる原因にもなる。According to the results of the investigation and research conducted by the present inventors, when the spheroidization rate of the carbide is regulated to 90% or more and the average particle diameter of the spheroidized carbide is regulated to 0.6 μm or less, the fracture surface is roughened. And the punched member excellent in fatigue characteristics was obtained. In the present specification, when the ratio (p / q) of the maximum length p of the carbide in the observation field of view of the steel plate cross section and the maximum length q in the direction orthogonal thereto is less than 3, the carbide is spheroidized. The number ratio of the spheroidized carbide to the total carbide was defined as the spheroidization ratio. If the spheroidization ratio is less than 90%, a secondary shear surface is likely to be generated on the punched surface, and the fatigue characteristics are deteriorated. Furthermore, the equivalent circle diameter was calculated from the area of each spheroidized carbide, and the value obtained by dividing the total number of equivalent circle diameters by the total number of measured spherical carbides was defined as the average particle diameter of the spheroidized carbide. If the average particle size of the spheroidized carbide exceeds 0.6 μm, the size of minute cracks and voids generated on the punched surface near the fractured surface becomes large, the fractured surface becomes rough, and the fatigue characteristics deteriorate. Coarse spheroidized carbide is
It remains without solid solution at the time of heat treatment, and also causes a decrease in toughness after heat treatment.
【0016】以下、本発明で使用する鋼板に含まれる合
金成分及び含有量を説明する。C:0.3〜0.8質量% 鋼材の強度及び靭性の向上に有効な合金成分であり、4
5HRC以上の硬さを得るためには0.3質量%以上の
C含有量が必要である。しかし、C含有量の増加に従っ
て炭化物量が多くなる。0.8質量%を超えるC含有量
では、粒界にセメンタイトが析出することが避けられ
ず、硬さが大きく上昇し、打抜き金型の寿命を低下させ
る原因になる。また、C含有量の増加によってMs点が
下がり残留オーステナイトが生成しやすくなるため、靭
性及び疲労特性が低下する。Hereinafter, alloy components and contents contained in the steel sheet used in the present invention will be described. C: An alloy component effective for improving the strength and toughness of the steel material of 0.3 to 0.8 mass% ,
To obtain a hardness of 5 HRC or more, a C content of 0.3 mass% or more is required. However, the amount of carbide increases as the C content increases. When the C content exceeds 0.8% by mass, precipitation of cementite at the grain boundary is inevitable, and the hardness is greatly increased, which causes a reduction in the life of the punching die. In addition, the increase in the C content lowers the Ms point, making it easier to generate retained austenite, and thus lowers toughness and fatigue properties.
【0017】Si:3.0質量%以下 製鋼段階で脱酸剤として添加される合金成分であるが、
焼入れ性を高め、フェライトを固溶強化する作用も呈す
る。また、熱処理時に炭化物の析出を遅延させる効果も
あるが、熱延,焼鈍,熱処理等の際に表面直下に内部酸
化を生じさせる原因になる。また、過剰量のSi含有は
鋼板を硬質化し、打抜き金型の負荷が大きくなる。これ
らの悪影響を避けるため、Si含有量の上限を3.0質
量%に設定した。なお、本発明で使用される鋼材は、M
n,Al等によっても脱酸されることから、基本的にS
i無添加とすることもできる。 Si: 3.0 mass% or less Si is an alloy component added as a deoxidizing agent in a steelmaking stage.
It also has the effect of enhancing hardenability and strengthening solid solution of ferrite. It also has the effect of delaying the precipitation of carbides during heat treatment, but causes internal oxidation immediately below the surface during hot rolling, annealing, heat treatment, and the like. Further, an excessive amount of Si hardens the steel sheet and increases the load on the punching die. To avoid these adverse effects, the upper limit of the Si content was set to 3.0% by mass. The steel material used in the present invention is M
deoxidation by n, Al, etc.
i may not be added.
【0018】Mn:1.5質量%以下 製鋼段階で脱酸剤として添加される合金成分であり、焼
入れ性を高める作用を呈する。しかし、打抜き加工時に
微小クラックの起点となるMn系の非金属介在物の形成
により破断面を粗くし、縞状組織の発達によって靭性を
低下させる悪影響を及ぼす。そのため、本発明ではMn
含有量の上限を1.5質量%に設定した。なお、本発明
で使用される鋼材は、Si,Al等によっても脱酸され
ることから、基本的にMn無添加とすることもできる。Cr:2.0質量%以下 焼入れ性,熱処理後の強度及び靭性向上に有効な合金成
分であり、焼鈍中に黒鉛化を防止する作用も呈する。し
かし、2.0質量%を超える過剰量のCrが含まれる
と、却って靭性が低下し、球状化焼きなましが困難にな
ると共に、中間製品の製造性が著しく劣化する。また、
Cr含有量の増加に伴って鋼板が著しく硬質化し、打抜
き金型への負荷が大きくなる。焼入れ性,熱処理後の強
度及び靭性の確保は、他の合金成分でも補われるので、
基本的にCr無添加とすることもできる。 Mn: 1.5 mass% or less Mn is an alloy component added as a deoxidizing agent in a steelmaking stage, and has an effect of enhancing hardenability. However, during punching, the formation of Mn-based nonmetallic inclusions serving as starting points of microcracks causes the fracture surface to be roughened, and the development of stripe structures adversely affects toughness. Therefore, in the present invention, Mn
The upper limit of the content was set to 1.5% by mass. Since the steel used in the present invention is also deoxidized by Si, Al and the like, Mn can be basically added without addition. Cr: 2.0% by mass or less Cr is an alloy component effective for improving hardenability, strength and toughness after heat treatment, and also has an effect of preventing graphitization during annealing. However, when an excessive amount of Cr exceeding 2.0% by mass is contained, the toughness is rather lowered, the spheroidizing annealing becomes difficult, and the productivity of the intermediate product is significantly deteriorated. Also,
As the Cr content increases, the steel sheet becomes extremely hard, and the load on the punching die increases. As the hardenability, strength after heat treatment and toughness are compensated by other alloy components,
Basically, Cr may not be added.
【0019】Cu:0.5質量%以下 焼入れ性及び熱処理後の靭性向上に有効であり、補助的
に添加される合金成分である。しかし、0.5質量%を
超える過剰量のCu添加は、熱間脆性を引き起こす原因
となる。N:0.0005〜0.02質量% V,Al,Ti,Nb等と窒化物や炭窒化物を形成し、
オーステナイト粒を微細化する。このような効果は、
V,Al,Ti,Nb等と複合添加されるとき、0.0
005質量%以上のN含有量で顕著になる。しかし、
0.02質量%を超えるN含有量では、微細化効果が飽
和し、却って靭性,疲労特性を低下させる悪影響が現れ
る。 Cu: 0.5% by mass or less Cu is an alloy component that is effective for improving hardenability and toughness after heat treatment and is added supplementarily. However, excessive addition of Cu exceeding 0.5% by mass causes hot embrittlement. N: 0.0005 to 0.02% by mass V, Al, Ti, Nb and the like form nitrides and carbonitrides,
Austenite grains are refined. These effects are
When combined with V, Al, Ti, Nb, etc., 0.0
It becomes remarkable at an N content of 005 mass% or more. But,
If the N content exceeds 0.02% by mass, the refining effect is saturated, and the adverse effect of reducing the toughness and fatigue properties appears.
【0020】O:0.0005〜0.01質量% 打抜き加工時に微小クラックの起点となるAl2O3等の
非金属介在物を形成し、破断面を粗くする有害成分であ
る。非金属介在物は、疲労亀裂の起点になることもあ
る。Oは、焼入れ焼戻し後の靭性及び疲労特性を劣化さ
せる成分でもある。このようなことからO含有量は低い
ほど好ましいが、過度にO含有量を低減することは製造
コストの上昇を招くので下限を0.0005質量%と
し、Oによる悪影響が現れない上限を0.01質量%に
規定した。P:0.02質量%以下 結晶粒界に偏析し、焼入れ焼戻し後の靭性を低下させる
有害成分であることから、可能な限り低く抑えることが
好ましい。しかし、過度にP含有量を下げることは製造
コストを上昇させることになるので、靭性低下に悪影響
を及ぼさない範囲としてP含有量の上限を0.02質量
%に規定した。 O: 0.0005 to 0.01 mass% is a harmful component that forms non-metallic inclusions such as Al 2 O 3 that serve as starting points of microcracks at the time of punching, and roughens the fracture surface. Non-metallic inclusions can also be the origin of fatigue cracks. O is also a component that deteriorates toughness and fatigue properties after quenching and tempering. For this reason, the O content is preferably as low as possible. However, excessive reduction of the O content causes an increase in production cost. Therefore, the lower limit is set to 0.0005% by mass, and the upper limit at which the adverse effect of O does not appear is 0.1%. It was defined as 01% by mass. P: 0.02% by mass or less It is a harmful component that segregates at the crystal grain boundary and reduces the toughness after quenching and tempering. However, excessively lowering the P content increases the production cost. Therefore, the upper limit of the P content is set to 0.02% by mass as a range that does not adversely affect the toughness.
【0021】S:0.01質量%以下 MnS等の非金属介在物を形成し、鋼材の加工性,強
度,靭性に悪影響を及ぼす。圧延材ではMnSが圧延方
向に展伸されるため、鋼板の加工性,強度,靭性に面内
異方性が大きく現れる。打抜き加工時にあっては微小ク
ラックの起点になって破断面を粗くすると共に、非金属
介在物自体が疲労亀裂の起点になる。このような悪影響
を抑えるため、S含有量の上限を0.01質量%に規定
した。酸可溶Al:0.01〜0.10質量% 製鋼段階に脱酸剤として添加される合金成分であり、鋼
中のNと結合してAlNを形成し、熱処理時にオーステ
ナイト結晶粒の異常成長を抑制する作用を呈する。これ
らの作用は、酸可溶Alとして0.01質量%以上で顕
著になる。しかし、酸可溶Alの効果は0.10質量%
で飽和し、過剰量のAl添加は却って製造コストを上昇
させ、表面疵の増加等の欠陥も発生しやすくなる。 S: 0.01% by mass or less Nonmetallic inclusions such as MnS are formed, which adversely affects the workability, strength, and toughness of the steel material. In rolled material, MnS is stretched in the rolling direction, so that in-plane anisotropy appears significantly in the workability, strength, and toughness of the steel sheet. At the time of punching, it becomes a starting point of a minute crack to roughen the fracture surface, and the nonmetallic inclusion itself becomes a starting point of a fatigue crack. In order to suppress such adverse effects, the upper limit of the S content is set to 0.01% by mass. Acid-soluble Al: 0.01 to 0.10% by mass An alloy component added as a deoxidizing agent in the steelmaking stage, combines with N in steel to form AlN, and abnormal growth of austenite crystal grains during heat treatment The effect of suppressing is shown. These effects become remarkable at an acid-soluble Al content of 0.01% by mass or more. However, the effect of acid-soluble Al is 0.10% by mass.
And the addition of an excessive amount of Al rather increases the production cost, and defects such as increased surface flaws are more likely to occur.
【0022】Mo:0.1〜2.0質量% 必要に応じて添加される合金成分であり、Crと同様に
鋼材の焼入れ性,熱処理後の強度,靭性の向上に有効な
合金成分である。これらの効果は、0.1質量%以上の
Moで顕著になる。しかし、2.0質量%を超える過剰
量のMoが含まれると、却って靭性が低下し,球状化焼
きなましが困難になり,中間製品の製造性も著しく劣化
する。また、多量のMo含有は、鋼材を硬質化し、打抜
き金型の負荷を大きくする原因となる。Ni:0.1〜3.0質量% 必要に応じて添加される合金成分であり、焼入れ性,熱
処理後の靭性を向上する作用を呈する。Ni添加によっ
て強度,靭性を向上させることにより疲労特性も改善さ
れる。このような効果は,0.1質量%以上のNiで顕
著になる。しかし、3.0質量%を超える過剰量のNi
が含まれると、鋼材の硬質化が著しく、打抜き金型の負
荷が大きくなる。また、熱処理後の強度,靭性,亀裂伝
播抵抗を向上させる効果も飽和する。 Mo: 0.1 to 2.0 mass% Mo is an alloy component added as necessary, and is an alloy component effective for improving the quenchability, strength after heat treatment, and toughness of a steel material like Cr. . These effects become remarkable with 0.1% by mass or more of Mo. However, when an excessive amount of Mo exceeding 2.0% by mass is contained, the toughness is rather lowered, the spheroidizing annealing becomes difficult, and the productivity of the intermediate product is significantly deteriorated. Also, a large Mo content hardens the steel material and causes an increase in the load on the punching die. Ni: 0.1 to 3.0% by mass An alloy component added as necessary, and has an effect of improving hardenability and toughness after heat treatment. Improving strength and toughness by adding Ni also improves fatigue characteristics. Such an effect becomes remarkable with Ni of 0.1% by mass or more. However, an excessive amount of Ni exceeding 3.0% by mass
Is included, the steel material is remarkably hardened, and the load on the punching die increases. Further, the effect of improving the strength, toughness, and crack propagation resistance after the heat treatment is saturated.
【0023】V:0.01〜0.5質量% 必要に応じて添加される合金成分であり、鋼中で炭化物
を形成し、強度及び靭性を向上させると共に、旧オース
テナイト結晶粒を微細化する作用によって亀裂伝播抵抗
を向上させる作用も呈する。このような作用は、0.0
1質量%以上のVで顕著になるが、0.5質量%を超え
る過剰量のVが含まれると強度,靭性,亀裂伝播抵抗を
向上させる効果が飽和し、却って中間製品の製造性が劣
化する。Ti:0.01〜0.1質量% 必要に応じて添加される合金成分であり、熱処理時に固
溶しにくい炭窒化物を形成し、焼入れ加熱時にオーステ
ナイト結晶粒の粗大化を抑制し、亀裂伝播抵抗を高める
作用を呈する。また、Ti添加によってNが固定される
ため、結晶粒界の強化に作用する有効B量が確保され
る。このような作用は、0.01質量%以上のTiで顕
著になる。しかし、0.1質量%を超える過剰量のTi
が含まれると、粗大な窒化物が形成されやすく、靭性の
低下を招く。 V: 0.01 to 0.5% by mass An alloy component added as necessary, forms carbide in steel, improves strength and toughness, and refines austenite crystal grains. The effect also improves the crack propagation resistance. Such an effect is 0.0
Although it becomes remarkable at V of 1% by mass or more, when an excessive amount of V exceeding 0.5% by mass is contained, the effect of improving the strength, toughness, and crack propagation resistance is saturated, and on the contrary, the productivity of the intermediate product is deteriorated. I do. Ti: 0.01 to 0.1% by mass An alloy component added as required, forms a carbonitride that is hardly dissolved during heat treatment, suppresses austenite crystal grains from being coarsened during quenching heating, and cracks. It has the effect of increasing propagation resistance. Further, since N is fixed by the addition of Ti, an effective B amount that acts to strengthen the crystal grain boundary is secured. Such an effect becomes remarkable with 0.01% by mass or more of Ti. However, an excessive amount of Ti exceeding 0.1% by mass
, Coarse nitrides are likely to be formed, leading to a decrease in toughness.
【0024】Nb:0.01〜0.2質量% 必要に応じて添加される合金成分であり、安定な炭窒化
物を形成し、V,Tiと同様に焼入れ時に結晶粒の粗大
化を抑制し、靭性の劣化を防止する作用を呈する。この
ような作用は,0.01質量%以上のNbで顕著にな
る。しかし、0.2質量%を超える過剰量のNbが含ま
れると、マトリックスに対する炭化物の固溶が減少し、
強度低下を招く。B:0.0005〜0.01質量% 必要に応じて添加される合金成分であり、焼入れ性を向
上させると共に、結晶粒界へのPの偏析を抑制して粒界
破壊に起因する靭性の低下を防止する。このような作用
は、0.0005質量%以上のBで顕著になり、0.0
1質量%で飽和する。なお、添加したBがNと結合して
窒化物BNになると、有効B量が減少するため、Tiと
の複合添加によりNをTiNとして固定することが好ま
しい。 Nb: 0.01 to 0.2 mass% Nb is an alloy component added as necessary, forms a stable carbonitride, and suppresses coarsening of crystal grains at the time of quenching like V and Ti. And has an effect of preventing deterioration of toughness. Such an effect becomes remarkable with Nb of 0.01% by mass or more. However, when an excessive amount of Nb exceeding 0.2% by mass is contained, the solid solution of the carbide in the matrix decreases,
This leads to a decrease in strength. B: 0.0005 to 0.01% by mass An alloy component added as necessary, improves the hardenability, suppresses the segregation of P at the crystal grain boundaries, and reduces the toughness caused by grain boundary fracture. Prevent drop. Such an effect becomes remarkable at 0.0005% by mass or more of B,
Saturates at 1% by weight. When the added B combines with N to form a nitride BN, the effective B amount is reduced. Therefore, it is preferable to fix N as TiN by adding it in combination with Ti.
【0025】本発明鋼板は,所定形状に打ち抜かれた
後、所定の強度を付与するため、必要に応じて45HR
C以上に調質される。調質のための熱処理は、焼入れ又
は焼き入れ・焼戻しが一般的であるが、材料によっては
オーステンパー,マルテンパー等の恒温処理を施しても
よい。また、熱処理後の打抜き加工部品をショットピー
ニングすると、疲労特性が更に向上する。一般に疲労強
度は材料強度の上昇に伴って高くなる傾向があるが、強
度レベルが45HRC以上になると材料表面の欠陥に対
する感受性が高くなり、必ずしも強度上昇が疲労強度の
上昇につながらなくなる。すなわち、疲労特性が要求さ
れる用途に打抜き加工部品を使用する場合、強度レベル
が45HRC以上になると打抜き面性状の影響が大きく
なる。この点、本発明鋼板から得られた打抜き加工部品
では、二次剪断面がなく破断面の最大高低差Ryを10
0μm以下に規制した打抜き面を備えているので、45
HRC以上の強度に調質しても打抜き面性状に起因する
疲労特性の劣化が抑えられる。The steel sheet of the present invention is punched into a predetermined shape and then given a 45 HR if necessary to impart a predetermined strength.
Tempered above C. The heat treatment for refining is generally quenching or quenching / tempering, but depending on the material, a constant temperature treatment such as austempering or martempering may be performed. In addition, when the punched part after the heat treatment is shot peened, the fatigue characteristics are further improved. Generally, the fatigue strength tends to increase as the material strength increases. However, when the strength level is 45 HRC or more, the susceptibility to defects on the material surface increases, and the increase in strength does not always lead to the increase in fatigue strength. That is, when a punched part is used for an application requiring fatigue characteristics, the effect of the punched surface properties increases when the strength level is 45 HRC or more. In this regard, in the stamped part obtained from the steel sheet of the present invention, there is no secondary shear surface, and the maximum height difference Ry of the fracture surface is 10%.
Since it has a punching surface regulated to 0 μm or less, 45
Even if tempering is performed to a strength equal to or higher than HRC, deterioration of fatigue characteristics due to punched surface properties can be suppressed.
【0026】[0026]
【実施例】表1に示した組成の鋼を転炉で溶製し、スラ
ブに連続鋳造した。このスラブを板厚2.6mmに熱間
圧延した。得られた熱延板に酸洗及び焼きなましを施し
た後、冷間圧延によって板厚1.2mmとし硬さを調整
した。焼きなまし及び冷間圧延条件を表2に示す。EXAMPLES Steel having the composition shown in Table 1 was melted in a converter and continuously cast into slabs. This slab was hot-rolled to a thickness of 2.6 mm. After pickling and annealing the obtained hot-rolled sheet, the sheet thickness was adjusted to 1.2 mm by cold rolling to adjust the hardness. Table 2 shows the annealing and cold rolling conditions.
【0027】 [0027]
【0028】 [0028]
【0029】得られた各素材から圧延方向に沿った長さ
が200mmで幅30mmの短冊状試験片を切り出し、
クリアランスを変化させながら試験片の中央部に直径1
0mmの打抜き孔を穿設した。打抜き加工された試験片
を870℃×15分加熱した後、焼入れし、次いで30
0℃に100分間焼き戻すことにより調質した。調質前
後で試験片の硬さ,炭化物の球状化率,球状化炭化物の
平均粒径,破断面の最大高低差Ryを測定すると共に,
打抜き加工で生じた打抜き面を目視観察して二次剪断面
の有無を調査した。最大高低差Ryは、レーザ顕微鏡を
用いて打抜き加工で生じた打抜き面を観察することによ
り検出した。また、油圧式疲労試験機で引張荷重を20
Hzで繰り返し加え、破断サイクルが105回の時間強
度で疲労特性を評価した。From each obtained material, a strip-shaped test piece having a length of 200 mm and a width of 30 mm along the rolling direction was cut out,
While changing the clearance, a diameter of 1
A punched hole of 0 mm was formed. The punched test piece was heated at 870 ° C. for 15 minutes, then quenched,
It was tempered by tempering to 0 ° C for 100 minutes. Before and after tempering, the hardness of the specimen, the spheroidization rate of the carbide, the average particle size of the spheroidized carbide, and the maximum height difference Ry of the fracture surface were measured.
The punched surface generated by the punching process was visually observed to check for the presence of a secondary shear plane. The maximum height difference Ry was detected by observing a punched surface generated by punching using a laser microscope. In addition, a tensile load of 20
Fatigue properties were evaluated at a time strength of 10 5 break cycles.
【0030】表3の調査結果にみられるように、比較例
1〜3では破断面粗さが本発明で規定した範囲にあり、
二次剪断面のない打抜き面が得られている。しかし、C
含有量が低い試験番号1(比較例)では強度が不足し、
疲労寿命も短かった。試験番号2(比較例)では、Ms
点を下げるC及びMnを過剰に含んでおり、残留オース
テナイトを含む不安定な組織になっていたことから、調
質後に50HRC以上の硬さが確保されるものの疲労寿
命が短かった。試験番号3(比較例)も、S,O等の不
純物元素を多量に含むため、50HRC以上の硬さを確
保できるが、疲労寿命が短かった。また、表面粗さRy
と破断サイクル105回の時間強度との関係を調査した
図1から明らかなように、表面粗さRy100μm以下
で時間強度が大幅に向上していることが判る。As can be seen from the survey results in Table 3, in Comparative Examples 1 to 3, the fracture surface roughness was within the range specified by the present invention.
A punched surface without a secondary shear plane is obtained. But C
In Test No. 1 (Comparative Example) having a low content, the strength was insufficient,
The fatigue life was also short. In test number 2 (comparative example), Ms
Since C and Mn lowering the point were excessively contained and the structure had an unstable structure including retained austenite, the fatigue life was short although hardness of 50 HRC or more was secured after tempering. Test No. 3 (Comparative Example) also contained a large amount of impurity elements such as S and O, so that a hardness of 50 HRC or more could be secured, but the fatigue life was short. Also, the surface roughness Ry
And breaking the cycle 10 5 times As is apparent from FIG. 1 of investigating the relationship between time strength, it is understood that the time-intensity below the surface roughness Ry100μm is greatly improved.
【0031】成分的には本発明で規定した条件を満足す
るE鋼であっても、素材硬さや球状化炭化物の平均粒径
が本発明で規定した範囲を外れる試験番号9,11(比
較例)では、破断面が粗くなっており、疲労寿命が短か
った。試験番号10,12(比較例)では、二次剪断面
のある打抜き面が生じたことから、短い疲労寿命を示し
た。これに対し、試験番号4〜8(本発明例)では、何
れも破断面の最大高低差Ryが100μm以下で且つ二
次剪断面のない打抜き面が生じており、成分的にも本発
明で既定した条件を満足することと相俟って、優れた疲
労特性を示していた。この対比から明らかなように、特
定された成分設計及び打抜き面性状の制御により、調質
した後でも優れた疲労特性を呈する打抜き加工用鋼板が
得られることが確認された。Even though the steel E satisfies the conditions specified in the present invention in terms of components, Test Nos. 9 and 11 in which the hardness of the material and the average particle size of the spheroidized carbide are out of the ranges specified in the present invention (Comparative Examples) In (), the fracture surface was rough and the fatigue life was short. In Test Nos. 10 and 12 (Comparative Examples), a short fatigue life was exhibited because a punched surface having a secondary shear surface was formed. On the other hand, in Test Nos. 4 to 8 (Examples of the present invention), a punched surface having a maximum height difference Ry of the fractured surface of 100 μm or less and having no secondary shearing surface was produced, and the present invention was also used as a component. Excellent fatigue characteristics were shown in combination with satisfying the prescribed conditions. As is clear from this comparison, it was confirmed that the specified component design and control of the punched surface properties can provide a punched steel sheet exhibiting excellent fatigue properties even after tempering.
【0032】 [0032]
【0033】[0033]
【発明の効果】以上に説明したように、本発明の打抜き
加工用鋼板は、成分が特定された鋼板を使用すると共
に、打抜き面の性状を管理することにより、形状精度の
良好な製品が得られると共に、調質後においても優れた
疲労特性を呈する。As described above, the steel sheet for stamping according to the present invention uses a steel sheet having specified components, and by controlling the properties of the punched surface, a product having good shape accuracy can be obtained. And exhibit excellent fatigue properties even after tempering.
【図1】 表面粗さRyと破断サイクル105回が得ら
れる時間強度との関係を表したグラフFigure 1 is a graph surface roughness Ry and break cycles 10 5 times showing a relationship between time obtained intensity
───────────────────────────────────────────────────── フロントページの続き (72)発明者 飯原 勝之 広島県呉市昭和町11番1号 日新製鋼株式 会社技術研究所内 (72)発明者 壽福 博之 広島県呉市昭和町11番1号 日新製鋼株式 会社技術研究所内 (72)発明者 甲谷 昇一 広島県呉市昭和町11番1号 日新製鋼株式 会社技術研究所内 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Katsuyuki Iihara, 111-1 Showa-cho, Kure-shi, Hiroshima Nisshin Steel Co., Ltd. Technical Research Institute (72) Inventor Hiroyuki Sufuku 11-1, Showa-cho, Kure-shi, Hiroshima Nisshin Steel Co., Ltd. (72) Inventor Shoichi Koya 11-1 Showa-cho, Kure City, Hiroshima Prefecture Nisshin Steel Co., Ltd.
Claims (4)
0質量%以下,Mn:1.5質量%以下,Cr:2.0
質量%以下,Cu:0.5質量%以下,N:0.000
5〜0.02質量%,O:0.0005〜0.01質量
%,P:0.02質量%以下,S:0.01質量%以
下,酸可溶Al:0.01〜0.10質量%を含み、残
部が実質的にFeの組成をもち、打抜き加工後に最大応
力が作用する位置の打抜き面における破断面粗さがRy
100μm以下、破断面の二次剪断比率が0となること
を特徴とする打抜き加工用鋼板。1. C: 0.3 to 0.8% by mass, Si: 3.
0 mass% or less, Mn: 1.5 mass% or less, Cr: 2.0
% By mass, Cu: 0.5% by mass or less, N: 0.000
5 to 0.02 mass%, O: 0.0005 to 0.01 mass%, P: 0.02 mass% or less, S: 0.01 mass% or less, acid-soluble Al: 0.01 to 0.10 Mass%, and the balance substantially has the composition of Fe, and the fracture surface roughness of the punched surface at the position where the maximum stress acts after the punching is Ry.
A steel sheet for punching, characterized in that the secondary shear ratio of the fractured surface is 100 μm or less and the secondary shear ratio is 0.
i:0.1〜3.0質量%,V:0.01〜0.5質量
%,Ti:0.01〜0.1質量%,Nb:0.01〜
0.2質量%,B:0.0005〜0.01質量%の1
種又は2種以上を含む請求項1記載の打抜き加工用鋼
板。2. Mo: 0.1 to 2.0% by mass, N
i: 0.1 to 3.0% by mass, V: 0.01 to 0.5% by mass, Ti: 0.01 to 0.1% by mass, Nb: 0.01 to
0.2% by mass, B: 0.0005 to 0.01% by mass
The steel sheet for stamping according to claim 1, wherein the steel sheet comprises at least one kind.
範囲にある請求項1又は2記載の打抜き加工用鋼板。3. The steel sheet for stamping according to claim 1, wherein the Vickers hardness is in the range of 200 to 400 HV.
0.6μm以下の球状化炭化物が分散したフェライト+
炭化物の組織をもつ鋼板を使用する請求項1〜3何れか
に記載の打抜き加工用鋼板。4. Ferrite in which spheroidized carbide having a spheroidization ratio of carbide of 90% or more and an average particle size of 0.6 μm or less is dispersed.
The steel sheet for punching according to any one of claims 1 to 3, wherein the steel sheet has a carbide structure.
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JP2000247244A JP2002060888A (en) | 2000-08-17 | 2000-08-17 | Steel sheet for blanking |
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Cited By (8)
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JP2009215612A (en) * | 2008-03-11 | 2009-09-24 | Nisshin Steel Co Ltd | Medium-high carbon steel sheet excellent in workability and production method therefor |
JP2010229430A (en) * | 2009-03-25 | 2010-10-14 | Nisshin Steel Co Ltd | Steel sheet blank for machine part and method of producing the same |
JP2011168842A (en) * | 2010-02-18 | 2011-09-01 | Nippon Steel Corp | High carbon steel sheet having reduced anisotropy and excellent hardenability, and method for producing the same |
WO2012176834A1 (en) * | 2011-06-22 | 2012-12-27 | 株式会社リケン | Pressure ring and fabrication method therefor |
WO2013133295A1 (en) * | 2012-03-08 | 2013-09-12 | 日立金属株式会社 | Carbon tool steel strip |
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Cited By (14)
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JP2009215612A (en) * | 2008-03-11 | 2009-09-24 | Nisshin Steel Co Ltd | Medium-high carbon steel sheet excellent in workability and production method therefor |
JP2010229430A (en) * | 2009-03-25 | 2010-10-14 | Nisshin Steel Co Ltd | Steel sheet blank for machine part and method of producing the same |
JP2011168842A (en) * | 2010-02-18 | 2011-09-01 | Nippon Steel Corp | High carbon steel sheet having reduced anisotropy and excellent hardenability, and method for producing the same |
CN103620275A (en) * | 2011-06-22 | 2014-03-05 | 株式会社理研 | Pressure ring and fabrication method therefor |
JP2013007404A (en) * | 2011-06-22 | 2013-01-10 | Riken Corp | Pressure ring and fabrication method therefor |
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JP2015057516A (en) * | 2013-08-12 | 2015-03-26 | 株式会社リケン | Pressure ring |
JP2015161346A (en) * | 2014-02-26 | 2015-09-07 | 株式会社ハーモニック・ドライブ・システムズ | Flexible external tooth gear of wave gear device and manufacturing method thereof |
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