JP2598532B2 - Metal sheet for press working with excellent formability - Google Patents

Description

【発明の詳細な説明】 ＜産業上の利用分野＞ 本発明は、幅広い成形余裕範囲を有するプレス加工用
金属薄板に関するものである。DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a metal sheet for press working having a wide range of forming allowance.

＜従来の技術＞ 一般に、プレス加工用鋼板は、しわや割れ等の欠陥を
生じることなく、安定して成形できることが強く要求さ
れる。前記欠陥は金型内における材料の流れ込み易さに
大きく影響される。されはプレス成形条件、鋼板の機械
的性質と密接な関係にあることはいうまでもないが、金
型と鋼板間に作用する摺動抵抗（摩擦抵抗）に関与する
鋼板の表面粗さも一つの要因と考えられてきた。<Related Art> Generally, a steel sheet for press working is strongly required to be able to be formed stably without generating defects such as wrinkles and cracks. The defects are greatly affected by the ease with which the material flows into the mold. However, it is needless to say that the press forming conditions and the mechanical properties of the steel sheet are closely related, but the surface roughness of the steel sheet related to the sliding resistance (friction resistance) acting between the die and the steel sheet is also one. It has been considered a factor.

鋼板はプレス加工性を高めるために、表面上に微細な
凹凸を有するダルロールによって調質圧延することによ
り、一定の粗さを付与される。従来、ロール表面のダル
加工法としてはショットブラスト法、放電ダル加工法が
用いられてきたが、両方法ともまず均一な粗度表面を得
ることが目的で、微妙な制御性という点では原理的に限
界がある。The steel sheet is given a certain roughness by temper rolling with a dull roll having fine irregularities on the surface in order to enhance press workability. Conventionally, shot blasting and discharge dulling have been used as dulling methods for roll surfaces, but both methods aim to obtain a uniform roughness surface first, and are fundamentally delicate in terms of controllability. Has limitations.

このため、近年上記の方法に代わり、例えば特開昭56
−119687号公報や特公昭58−25557号公報のように、レ
ーザ・ビームをパルス状に照射して、ロール表面に無数
の凹凸を規則的に形成するレーザダル加工法が採られて
いる。しかしながら、そのダル形状、寸法の自由度は限
られており、プレス加工に適した凹凸形状を意図的に付
与するまでには至っていないのが現状である。For this reason, in recent years, instead of the above method,
As disclosed in JP-A-119687 and JP-B-58-25557, a laser dulling method is employed in which a laser beam is radiated in a pulse shape to form a myriad of irregularities on the roll surface regularly. However, the degree of freedom of the dull shape and dimensions is limited, and at present, it has not reached the point where a concavo-convex shape suitable for press working is intentionally given.

そして、プレス加工用鋼板はその機械的性質、表面粗
度等を踏まえた最適なしわ押え力のもとで、連続的に大
量に加工されるが、同一材質の鋼板でも突如として成形
不良が発生する場合がある。その要因は、鋼板の成形余
裕範囲（しわを発生させないしわ押え力の下限値から、
割れを起こさないそれの上限値までの範囲）が狭いた
め、成形時の微妙な条件変化に対応できない、あるい
は、成形条件の厳しい部位における局所的な面圧上昇に
よる型かじりによって、鋼板の型内への流れ込みが不均
一になることなどが考えられる。The steel sheet for press working is continuously processed in large quantities under the optimum wrinkle holding force based on its mechanical properties, surface roughness, etc., but suddenly molding defects occur even with steel sheets of the same material. May be. The reason is that the forming allowance range of the steel sheet (from the lower limit of wrinkle holding force
(The range up to the upper limit value that does not cause cracking) is too narrow to cope with subtle changes in conditions during molding, or due to galling due to local surface pressure increase in parts with severe molding conditions, It is conceivable that the flow into the nozzle becomes uneven.

＜発明が解決しようとする課題＞ 本発明は、上記の成形不良を極力抑えるために、金属
薄板の成形余裕範囲を改善すると同時に、高面圧下にお
ける耐型かじり性をも向上させられるような、表面凹凸
構造を備えたプレス加工用金属薄板を提供することを目
的とする。<Problems to be Solved by the Invention> The present invention is to improve the molding margin range of a thin metal sheet, and to improve the mold galling resistance under a high surface pressure, in order to suppress the above-described molding defects as much as possible. An object of the present invention is to provide a metal sheet for press working having a surface uneven structure.

＜課題を解決するための手段＞ 本発明は、金属板表面に大小２種類の池状凹部が形成
され、小さな池状凹部は大きな池状凹部を除く平坦部上
に設けられ、かつ該各凹部はそれぞれが連結しないよう
に形成されたことを特徴とする成形性に優れたプレス加
工用金属薄板である。<Means for Solving the Problems> According to the present invention, two types of large and small pond-shaped recesses are formed on the surface of a metal plate, and the small pond-shaped concave portions are provided on a flat portion excluding the large pond-shaped concave portions. Is a metal sheet for press working excellent in formability characterized by being formed so as not to be connected to each other.

また、本発明では、前記池状凹部の面積率が20％以
上、前記池状凹部の深さが10μｍ以下で、かつ前記小さ
な池状凹部の寸法がその平面形状における面積等価円の
直径で10〜90μｍ、前記大きな池状凹部の寸法がその平
面形状における面積等価円の直径で100〜280μｍである
ことが好ましい。Further, in the present invention, the area ratio of the pond-shaped concave portion is 20% or more, the depth of the pond-shaped concave portion is 10 μm or less, and the size of the small pond-shaped concave portion is 10% as the diameter of the area equivalent circle in the planar shape. It is preferable that the size of the large pond is 100 to 280 μm in terms of the diameter of the area equivalent circle in the planar shape.

＜作 用＞ 一般に、薄鋼板はその多くが、絞り加工や張出し加工
等の機械的加工によって目的とする形状に成形される。<Operation> In general, most of thin steel sheets are formed into a target shape by mechanical processing such as drawing or stretching.

その際、しわ押え部、ダイ肩部等では鋼板表面と金型
表面が潤滑油を介して接触状態において、鋼板の移動に
よる摺動が起こる。この潤滑油の効果を十分発揮させる
ことが、高しわ押え力の条件でも、鋼板の流れ込みを助
長し、スムーズな成形を行うために必要である。At this time, in the wrinkle holding portion, the die shoulder portion, and the like, the steel plate moves and slides due to the movement of the steel plate when the surface of the steel plate and the die surface are in contact with each other via the lubricating oil. It is necessary to sufficiently exert the effect of the lubricating oil in order to promote the flow of the steel sheet and perform the smooth forming even under the condition of the high wrinkle holding force.

鋼板表面に溝状の凹部を形成した場合には、鋼板と金
型との境界面に存在する潤滑油は、金型との面圧によっ
てその溝に沿って流出し、その効果が発揮されない。When a groove-shaped concave portion is formed on the surface of the steel sheet, the lubricating oil present at the interface between the steel sheet and the mold flows out along the groove due to the surface pressure with the mold, and the effect is not exhibited.

これに対し、鋼板表面に池状の凹部を形成すると、潤
滑油は凹部にとどまり、金型との面圧、鋼板表面の変形
によって、凹部から鋼板と金型との接触面に供給され、
その役割を十分に果たすことが可能である。On the other hand, when a pond-shaped recess is formed on the surface of the steel sheet, the lubricating oil stays in the recess and is supplied from the recess to the contact surface between the steel sheet and the mold due to surface pressure with the mold and deformation of the steel sheet surface,
It is possible to fulfill that role.

但し、一つの部品をプレス成形する場合でも、各部位
で変形様式、面圧等の条件は異なる。また、池状の凹部
もその面積、深さ等の平面形状、断面形状により、耐え
られる面圧に限界があると考えられる。従って、単に池
状の凹部を鋼板表面に形成するだけでは、期待する効果
を得ることはできない。However, even when one part is press-formed, conditions such as a deformation mode and a surface pressure are different in each part. Also, it is considered that the pond-shaped recess has a limit to the surface pressure that can be withstood by its planar shape and cross-sectional shape such as its area and depth. Therefore, the expected effect cannot be obtained simply by forming a pond-shaped recess on the steel sheet surface.

そこで、低面圧で潤滑状態の優れた表面構造と高面圧
でのそれとをうまく組み合わせることによって、本発明
の目的を達成することが可能である。高面圧下に適する
表面構造を取り入れることで、局所的に発生する型かじ
りを防止できる確率が高いことはいうまでもない。Therefore, it is possible to achieve the object of the present invention by properly combining the surface structure excellent in a lubrication state at a low surface pressure with that at a high surface pressure. It is needless to say that by adopting a surface structure suitable for high surface pressure, there is a high probability of preventing mold galling occurring locally.

上記を考慮した鋼板表面の凹凸構造を模式的に示した
ものが第１図である。第１図（ａ）、（ｂ）は本発明の
鋼板表面の例を示す平面図、第１図（ｃ）、（ｄ）はそ
れぞれ第１図（ａ）、（ｂ）のＩ−Ｉ線、II−II線にお
ける断面形状を示す。すなわち、本発明では、鋼板表面
に大きな池状凹部と小さな池状凹部の大小２種類の池状
凹部が形成され、これら各凹部は独立してそれぞれが連
結しないように形成される。また、小さな凹部は大きな
凹部以外の、大きな凹部の周囲を構成する断面形状で凸
部にみえる領域（平坦部という）に形成される。凹部の
平面形状は正方形、円形を例としているが、どのような
形状でもかまわず、大きな凹部とその周囲を構成する図
１（ｃ）、（ｄ）に示す断面形状で凸部にみえる平坦部
上に形成された小さな凹部との形状が一致しなくても問
題はない。また、第１図の断面図では、凹部が矩形を呈
しているが、凹部から鋼板と金型との接触面への潤滑油
の供給のし易さを考えると、椀状あるいは皿状の方が望
ましい。平面図における凹部の配列も規則的であるが、
目的を逸脱しなければ、その配置も特に制約はしない。FIG. 1 schematically shows the uneven structure of the steel sheet surface in consideration of the above. FIGS. 1 (a) and 1 (b) are plan views showing examples of the steel sheet surface of the present invention, and FIGS. 1 (c) and 1 (d) are II lines in FIGS. 1 (a) and 1 (b), respectively. , II-II. That is, in the present invention, two large and small pond-shaped concave portions, a large pond-shaped concave portion and a small pond-shaped concave portion, are formed on the surface of the steel sheet, and these concave portions are formed independently so as not to be connected to each other. In addition, the small concave portion is formed in a region (referred to as a flat portion) which looks like a convex portion in a cross-sectional shape constituting the periphery of the large concave portion other than the large concave portion. The planar shape of the concave portion is, for example, a square or a circle, but may be any shape. A flat portion which has a large concave portion and a cross-sectional shape shown in FIGS. There is no problem even if the shape of the small recess formed on the top does not match. In addition, in the cross-sectional view of FIG. 1, the concave portion has a rectangular shape. However, considering the ease of supplying the lubricating oil from the concave portion to the contact surface between the steel plate and the mold, a bowl-shaped or a dish-shaped is preferable. Is desirable. The arrangement of the recesses in the plan view is also regular,
The arrangement is not particularly limited as long as the purpose is not deviated.

第１図に示す表面構造のプレス成形における効果とし
ては、低面圧（低しわ押え力）域では断面形状で凸部に
みえる平坦部上に構成された小さな凹部が活発な潤滑作
用を呈し、高面圧域に移行するに連れて、該凹部の効用
は失せ、それに代わり大きな凹部が鋼板の流れ込み易さ
を補う潤滑状態に寄与する。The effect of the surface structure shown in FIG. 1 in the press forming is as follows. In the low surface pressure (low wrinkle holding force) region, a small concave portion formed on a flat portion which looks like a convex portion in a cross-sectional shape exhibits an active lubricating action, As the region shifts to the high surface pressure region, the utility of the recesses is lost, and instead, the large recesses contribute to a lubricating state that compensates for the ease of flowing of the steel sheet.

従って、上記表面構造を有する鋼板では、しわが発生
しやすい低面圧域から、割れが発生しやすい高面圧域ま
での広範囲にわたる成形領域をカバーすることができる
ので、成形不良を起こす確率が極めて低くなり、製品歩
留り向上の点からも有利である。Therefore, the steel sheet having the above surface structure can cover a wide range of forming region from a low surface pressure region where wrinkles are likely to occur to a high surface pressure region where cracks are easily generated. This is extremely low, which is advantageous from the viewpoint of improving product yield.

また、鋼板と金型との接触面に侵入した異物を起点と
する型かじりなども、大きな凹部が異物の受け皿とな
り、未然にそれを防止する機能をも果たし得る。Also, in the case of a galling caused by a foreign substance that has entered the contact surface between the steel plate and the mold, the large concave portion serves as a receptacle for the foreign substance, and can also function to prevent the foreign matter from occurring.

次に、本発明の数値限定の理由について説明する。 Next, the reason for the numerical limitation of the present invention will be described.

池状凹部の幾何学的特性がプレス加工性に及ぼす影響
を調べるために、第７図に示すような表面を備えた２種
類の鋼板を調質圧延して製作した。この際、凹部中心間
を45゜の線で結んだ時、中心間距離が150μｍとなるよ
うに配列し、凹部の平面形状である正方形の一辺の長さ
を60μｍまたは120μｍとし、凹部の深さはほぼ５μｍ
に統一した。調質圧延に使用したロールは、印刷技術で
利用されるフォトエッチング法によって表面加工した。
ロール表面は、第７図の鋼板表面と全く反対の凹凸形状
を備えており、鋼板表面の凹部はロール表面では凸部に
相当する。In order to investigate the influence of the pond-shaped concave portion on the press workability, two types of steel sheets having a surface as shown in FIG. 7 were temper-rolled and manufactured. At this time, when the centers of the recesses are connected by a 45 ° line, the centers are arranged so that the distance between the centers is 150 μm, the length of one side of the square which is the planar shape of the recesses is 60 μm or 120 μm, and the depth of the recesses is Is approximately 5 μm
Unified. The roll used for the temper rolling was subjected to surface processing by a photo-etching method used in printing technology.
The roll surface has a concavo-convex shape completely opposite to the steel plate surface in FIG. 7, and the concave portion on the steel plate surface corresponds to the convex portion on the roll surface.

これらの鋼板の表面に潤滑油を塗布し、プレス加工性
を評価した。評価方法は、第８図に示すように、試験片
６の両面から先端20mmRの球面をもつ工具７に押付力８
を加えておき、この押付力８と直角方向９に試験片を引
き抜く摺動試験方法により、摺動抵抗を測定した。Lubricating oil was applied to the surfaces of these steel sheets, and press workability was evaluated. As shown in FIG. 8, the evaluation method is such that a pressing force 8 is applied to a tool 7 having a spherical surface with a tip of 20 mmR from both sides of the test piece 6.
The sliding resistance was measured by a sliding test method in which the test piece was pulled out in a direction 9 perpendicular to the pressing force 8.

第９図に押付力を50kgf、100kgf、200kgfと変化させ
たときの実験結果を示す。押付力50kgfでは、小さい凹
部を備えた鋼板の方が、大きい凹部を備えた鋼板より摺
動抵抗が低く、押付力が200kgfになると逆に、大きい凹
部の方が摺動抵抗は低くなる。押付力がプレス加工にお
ける、しわ押え力に相当するものと考えると、低面圧で
は鋼板表面に小さな凹部が存在する方が摺動抵抗を低く
保つことができ、面圧が高くなると大きな凹部の方がそ
の傾向が顕著になる。FIG. 9 shows the experimental results when the pressing force was changed to 50 kgf, 100 kgf, and 200 kgf. At a pressing force of 50 kgf, the sliding resistance of the steel plate having the small concave portion is lower than that of the steel plate having the large concave portion, and conversely, the sliding resistance of the large concave portion is lower when the pressing force is 200 kgf. Considering that the pressing force is equivalent to the wrinkle holding force in press working, it is possible to keep the sliding resistance low when there is a small recess on the steel sheet surface at low surface pressure, and to reduce the large recess when the surface pressure is high. This tendency becomes more pronounced.

次に、これらの大小凹部の適切な寸法を定めるための
実験を行った。まず、第７図に示すような表面を備えた
鋼板を、正方形凹部の一辺の長さ（一辺長）、あるいは
凹部中心間の長さを変えて、幾種類も作製し、第８図の
評価方法で摺動抵抗を調べた。Next, an experiment for determining appropriate dimensions of these large and small concave portions was performed. First, several types of steel plates having a surface as shown in FIG. 7 were prepared by changing the length of one side (one side length) of the square recess or the length between the centers of the recesses. The sliding resistance was examined by the method.

第10図は、押付力30kgfで試験片を引き抜いた時の摺
動抵抗を、凹部が占める面積率に対して、凹部の一辺長
をパラメータにグラフ化したものである。凹部の一辺長
が100μｍ以上では摺動抵抗にあまり変化は見られない
が、80μｍ以下では摺動抵抗が低下していき、特に凹部
面積率で25％以上を占めると更に顕著である。また、ロ
ール表面に意図的に付与できる凹凸の平面形状の最小径
は、フォトエッチング法などで使用されるレーザ・ビー
ムの径でも10μｍ程度である。これらのことから、小さ
な凹部の寸法は円、多角形等のあらゆる形状とその所有
面積を考慮して、凹部平面形状の外径、すなわち平面形
状における面積等価円の直径で10〜90μｍが適してい
る。FIG. 10 is a graph in which the sliding resistance when the test piece is pulled out with a pressing force of 30 kgf is plotted against the area ratio occupied by the concave portion and the length of one side of the concave portion as a parameter. When the length of one side of the concave portion is 100 μm or more, there is little change in the sliding resistance. However, when the side length is 80 μm or less, the sliding resistance decreases, and it is more remarkable especially when the concave portion occupies 25% or more. Further, the minimum diameter of the planar shape of the concavities and convexities that can be intentionally applied to the roll surface is about 10 μm even for the diameter of a laser beam used in a photoetching method or the like. From these facts, the size of the small recess is preferably the outer diameter of the recess planar shape, that is, the diameter of the area equivalent circle in the planar shape of 10 to 90 μm, in consideration of all shapes such as a circle and a polygon and the possessed area thereof. I have.

第11図は、押付力200kgfにおける摺動抵抗を、第10図
と同様に表したものである。凹部の一辺長が100μｍ以
上で、凹部面積率が20％以上の場合に、摺動抵抗を低下
させるのに効果がある。但し、凹部の一辺長が250μｍ
を超えると、高い面圧でも凹部に存在する潤滑油を有効
に作用させることが困難になる。これらのことから、大
きな凹部の寸法は円、多角形等のあらゆる形状とその所
有面積を考慮して、凹部平面形状の外径、すなわち平面
形状における面積等価円の直径で100〜280μｍが適当で
ある。FIG. 11 shows the sliding resistance at a pressing force of 200 kgf in the same manner as in FIG. When the length of one side of the recess is 100 μm or more and the area ratio of the recess is 20% or more, it is effective to reduce the sliding resistance. However, the side length of the concave is 250 μm
If the pressure exceeds the range, it becomes difficult to effectively use the lubricating oil existing in the concave portion even at a high surface pressure. From these facts, the size of the large concave portion is suitably the outer diameter of the concave portion planar shape, that is, the diameter of the area equivalent circle in the planar shape of 100 to 280 μm in consideration of all shapes such as circles and polygons and the possessed area thereof. is there.

また、凹部の深さの影響は図示しないが、10μｍを超
えると摺動抵抗は大きくなる傾向にあるので、10μｍ以
下が望ましい。Although the influence of the depth of the concave portion is not shown, if it exceeds 10 μm, the sliding resistance tends to increase, so that it is preferably 10 μm or less.

＜実施例＞ 以下、本発明の実施例について説明する。<Example> Hereinafter, an example of the present invention will be described.

ロール表面のダル加工法に公知の技術フォトエッチン
グ法を用い、規則的な正方形の台地状の突起を有する調
質圧延用ロールを３種類作製した。これらのロールの表
面構造の代表的寸法を、第２図の記号に従い、表１に示
す。Three types of rolls for temper rolling having regular square plateau-like projections were produced by using a known technique of photo-etching as a method of dulling the roll surface. Representative dimensions of the surface structure of these rolls are shown in Table 1 according to the symbols in FIG.

調質圧延の手順は、まず表１のロールNo.2又はNo.3を
使用し、第３図（ａ）に示すように大きな凹部を鋼板表
面に形成させた後、ロールNo.1により第３図（ｂ）のよ
うな小さな池状凹部を付与する。ロールNo.1とNo.2の組
み合わせで、第１図（ａ）、（ｂ）に示す鋼板が作製で
き、ロールNo.1とNo.3の組み合わせで、断面形状で凸部
にみえる平坦部上に１個の小さな池状凹部が存在する鋼
板表面となる。前者を発明鋼板１、後者を発明鋼板２と
する。 The procedure of the temper rolling is as follows. First, roll No. 2 or No. 3 in Table 1 is used to form a large recess on the steel sheet surface as shown in FIG. 3 A small pond-shaped recess as shown in FIG. The steel sheet shown in Fig.1 (a) and (b) can be manufactured by the combination of roll No.1 and No.2, and the flat part which looks like the convex part in the cross-sectional shape by the combination of roll No.1 and No.3 The steel plate surface has one small pond-shaped recess on top. The former is referred to as invention steel sheet 1 and the latter is referred to as invention steel sheet 2.

そして、大きな池状凹部を転写する際の圧下率を2.0
％としたところ、発明鋼板の大きな池状凹部深さは４μ
ｍ、発明鋼板２は５μｍとなり、さらに機械的性質を劣
化させない程度の軽圧下で、深さ２μｍの小さな池状凹
部が両者とも付与された。また、発明鋼板１の凹部の面
接率は58％、発明鋼板２の凹部の面積率は56％であっ
た。Then, the reduction rate when transferring large pond-shaped concave portions is 2.0
%, The depth of the large pond-shaped concave portion of the invention steel plate is 4 μm.
m, the thickness of the invention steel plate 2 was 5 μm, and both were provided with a small pond-like recess having a depth of 2 μm under light pressure that did not deteriorate the mechanical properties. In addition, the interview ratio of the concave portion of the inventive steel plate 1 was 58%, and the area ratio of the concave portion of the inventive steel plate 2 was 56%.

発明鋼板の性能を確認するために、第４図に示す円錐
台成形をブランク径210φ、成形高さ50mmの条件で実施
した。評価としては、しわ押え力を次第に増加させ、割
れが発生するときのしわ押え力を成形範囲の上限値と
し、下限値は第５図のような円錐台側面に発生したしわ
高さを測定し、その高さが3mm以下を示すときの最小し
わ押え力とし、その範囲の広いものほど、成形性に優れ
ていると判断することにした。In order to confirm the performance of the steel sheet of the invention, truncated conical forming shown in FIG. 4 was performed under the conditions of a blank diameter of 210 φ and a forming height of 50 mm. As the evaluation, the wrinkle holding force was gradually increased, and the wrinkle holding force when cracks occurred was taken as the upper limit of the forming range, and the lower limit was measured as the wrinkle height generated on the side of the truncated cone as shown in FIG. The minimum wrinkle holding force when the height was 3 mm or less was determined, and the wider the range, the better the moldability.

実験に先立ち比較鋼板も数種類用意し、評価した。比
較鋼板１はショット・ダル鋼板で、中心面平均粗さSRa
0.8μｍ、比較鋼板２はレーザ・ダル鋼板で、中心面平
均粗さSRa 1.0μｍである。比較鋼板３、４はそれぞれ
発明鋼板１の大きな凹部だけ、小さな凹部だけを所有す
る鋼板である。発明鋼板、比較鋼板とも同一原板からダ
ル圧延し、板厚は0.8mmである。Prior to the experiment, several types of comparative steel sheets were prepared and evaluated. Comparative steel plate 1 is a shot dull steel plate with a center plane average roughness SRa.
0.8 μm, Comparative steel plate 2 is a laser dull steel plate having a center plane average roughness SRa of 1.0 μm. The comparative steel plates 3 and 4 are steel plates having only the large concave portions and only the small concave portions of the inventive steel plate 1, respectively. Both the inventive steel sheet and the comparative steel sheet are dull rolled from the same original sheet, and the sheet thickness is 0.8 mm.

潤滑油として洗浄油を使用し、実験した結果を第６図
に示す。FIG. 6 shows the results of an experiment using a cleaning oil as a lubricating oil.

１種類の池状凹部だけを有する比較鋼板３、４でも、
比較鋼板１のショット・ダル鋼板、比較鋼板２のレーザ
・ダル鋼板よりも、成形余裕範囲の割れ限界がかなり改
善された。更に比較鋼板３、４を組み合わせた発明鋼板
１、また、発明鋼板１の大きな池状凹部と小さな池状凹
部の比率を少し変えた発明鋼板２では、大きさの異なる
凹部による相乗効果で、成形余裕範囲の飛翔的に拡張さ
れた。Even the comparative steel plates 3 and 4 having only one kind of pond-shaped recess,
The crack limit of the forming allowance range was considerably improved as compared with the shot dull steel sheet of Comparative Steel Sheet 1 and the laser dull steel sheet of Comparative Steel Sheet 2. Furthermore, in the invention steel plate 1 in which the comparative steel plates 3 and 4 are combined, and in the invention steel plate 2 in which the ratio of the large pond-like concave portion to the small pond-like concave portion of the inventive steel plate 1 is slightly changed, forming is performed by a synergistic effect of the concave portions having different sizes. The flight range has been expanded.

以上の実験結果により、鋼板表面に付与した池状の凹
部は、プレス成形性を向上させるのに有効であり、それ
を二重構造にすることで、格段の成果を得ることができ
たことが分かる。According to the above experimental results, the pond-shaped recess provided on the steel sheet surface is effective for improving the press formability, and by making it a double structure, it was possible to obtain remarkable results. I understand.

＜発明の効果＞ 以上説明したように、本発明によれば、金属板表面に
プレス成形に適した凹凸構造を施すことにより、成形余
裕範囲の広いプレス加工用金属薄板を提供することがで
き、歩留り向上の点からも有効である。<Effects of the Invention> As described above, according to the present invention, it is possible to provide a metal sheet for press working with a wide range of forming margins by applying a concavo-convex structure suitable for press forming on a metal sheet surface, It is also effective from the viewpoint of improving the yield.

【図面の簡単な説明】[Brief description of the drawings]

第１図（ａ）、（ｂ）は本発明の鋼板表面を例示した平
面図であり、第１図（ｃ）、（ｄ）はそれぞれ第１図
（ａ）、（ｂ）のＩ−Ｉ線、II−II線での断面図であ
る。第２図（ａ）は本発明鋼板を作製する際に使用した
調質圧延ロールの平面図で、第２図（ｂ）は第２図
（ａ）のIII−III線での断面図である。第３図は鋼板表
面に２種類の池状凹部を付与する調質圧延工程の説明図
である。第４図は成形余裕範囲を調査するために用いた
円錐台成形の概略図である。第５図は成形した円錐台側
面に発生したしわ形状としわ高さの測定箇所を示す斜視
図である。第６図は発明鋼板と比較鋼板について円錐台
成形を行った結果、得られた成形余裕範囲を示す図であ
る。第７図は本発明の実験に供した池状凹部の大きさが
異なる鋼板の表面状態を模式的に示した拡大図である。
第８図は第７図の鋼板のプレス加工性を評価する試験方
法の説明図である。第９図は摺動試験結果を示すグラフ
である。第10図及び第11図は凹部の寸法を規定するのに
用いたそれぞれ押付力30kgf、200kgfにおける摺動試験
結果を示したグラフである。 １……調質圧延ロール、２……鋼板、 ３……パンチ、４……ダイ、 ５……しわ押え、６……試験片、 ７……球面工具、８……押付力、 ９……引抜方向。1 (a) and 1 (b) are plan views illustrating the steel sheet surface of the present invention, and FIGS. 1 (c) and 1 (d) are II in FIGS. 1 (a) and 1 (b), respectively. FIG. 2 is a sectional view taken along line II-II. FIG. 2 (a) is a plan view of a temper roll used in producing the steel sheet of the present invention, and FIG. 2 (b) is a cross-sectional view taken along the line III-III of FIG. 2 (a). . FIG. 3 is an explanatory view of a temper rolling step of providing two types of pond-shaped recesses on the surface of a steel sheet. FIG. 4 is a schematic diagram of frustoconical molding used for investigating a molding margin range. FIG. 5 is a perspective view showing a wrinkle shape generated on the side surface of the formed truncated cone and a measurement point of a wrinkle height. FIG. 6 is a diagram showing a forming allowance range obtained as a result of performing truncated cone forming on the inventive steel sheet and the comparative steel sheet. FIG. 7 is an enlarged view schematically showing the surface states of steel plates having different sizes of the pond-shaped recesses used in the experiment of the present invention.
FIG. 8 is an explanatory diagram of a test method for evaluating the press workability of the steel sheet of FIG. FIG. 9 is a graph showing a sliding test result. FIG. 10 and FIG. 11 are graphs showing sliding test results at a pressing force of 30 kgf and 200 kgf, respectively, used for defining the dimensions of the recess. 1 ... Temper rolling roll, 2 ... steel plate, 3 ... punch, 4 ... die, 5 ... wrinkle holder, 6 ... test piece, 7 ... spherical tool, 8 ... pressing force, 9 ... Pull direction.

───────────────────────────────────────────────────── フロントページの続き (72)発明者 鑓田 征雄 千葉県千葉市川崎町１番地 川崎製鉄株 式会社技術研究本部内 (56)参考文献 特開 平２−37901（ＪＰ，Ａ) ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuo Yarida 1 Kawasaki-cho, Chiba City, Chiba Pref.

Claims (2)

(57)【特許請求の範囲】(57) [Claims] 【請求項１】金属板表面に大小２種類の池状凹部が形成
され、小さな池状凹部は大きな池状凹部を除く平坦部上
に設けられ、かつ該各凹部はそれぞれが連結しないよう
に形成されたことを特徴とする成形性に優れたプレス加
工用金属薄板。1. A large and small pond-shaped recess is formed on a surface of a metal plate, and the small pond is provided on a flat portion excluding the large pond, and each of the recesses is formed so as not to be connected to each other. Metal sheet for press working excellent in formability, characterized by being made. 【請求項２】前記池状凹部の面積率が20％以上、前記池
状凹部の深さが10μｍ以下で、かつ前記小さな池状凹部
の寸法がその平面形状における面積等価円の直径で10〜
90μｍ、前記大きな池状凹部の寸法がその平面形状にお
ける面積等価円の直径で100〜280μｍであることを特徴
とする成形性に優れたプレス加工用金属薄板。2. The area ratio of the pond-shaped recess is 20% or more, the depth of the pond-shaped recess is 10 μm or less, and the size of the small pond-shaped recess is 10 to 10 in terms of the diameter of the area equivalent circle in the planar shape.
A metal sheet for press working excellent in formability, characterized in that the size of the large concave portion is 100 to 280 μm in terms of the area equivalent circle diameter in the planar shape.