Method for manufacturing metal processed product, and metal processed product

Abstract

Provided is a method for manufacturing a metal processed product in which a level difference at a cut end can be suppressed while further increasing the plating-component remaining length at the cut end after finish cutting. A method for manufacturing a metal processed product according to the present invention comprises: a half-cutting step for half-cutting a first element body formed from a material in a plate thickness direction using a first die and a first punch to form a half-cut section; and a finish cutting step for finish-cutting the half-cut section in the same direction as in the half-cutting by using a second die and a second punch to obtain a metal processed product having a cut end. In the finish cutting step, the clearance between the first die and the first punch is modified to the clearance between the second die and the second punch by modifying the side surface position from that of the first die to that of the second die. The modification distance Md (mm) from the side surface position of the first die to the side surface position of the second die satisfies formula (b1): Md ≤ 0.25. The proportion of the clearance C32-42 between the second die and the second punch in the remaining plate thickness t2 of the half-cut section satisfies formula (b3-3):　(C32-42 / t2) × 100 ≤ 25.0 × t2-1 (b3-3)

Description

Manufacturing method of metal processed product and metal processed product

[0001] The present invention relates to a method for manufacturing a metal processed product using a plated metal sheet having a plating layer on its surface as a raw material and having a cut edge along the thickness direction of the raw material, and to the metal processed product.

[0002] In recent years, metal processed products made from plated metal sheets having a plating layer on the surface have increasingly been used as parts for devices such as automobiles and home appliances. By using plated metal sheets as the material, it is possible to omit the plating process after forming the metal processed product, thereby reducing manufacturing costs. Furthermore, by omitting the plating process after forming, it is possible to avoid deterioration of the dimensional accuracy of the part due to the plating process after forming. Omitting the plating process after forming is particularly considered for parts that require high dimensional accuracy, such as motor cases.

[0003] If plating after forming is omitted, areas of the metal sheet base material will be exposed at the cut edges of the metal processed product. Depending on the environment in which the processed product is placed, red rust may form in the exposed areas of the metal sheet base material. This red rust will deteriorate the appearance of the processed product.

[0004] Patent Document 1 listed below proposes a rust prevention removal method for cut ends, in which in a first step, a punch and die with an R-shaped cutting edge are used to perform half-cutting (half-blanking) with a negative clearance, and in a second step, an R is given only to the die (or punch) and a finish cut is performed with a positive clearance, thereby causing the surface plating layer to wrap around the end face of the cut end.

[0005] International Publication No. 2022 / 039168

[0006] Furthermore, the present inventors have been studying methods for increasing the length of the plating component remaining at the cut end after finish cutting in order to enhance the rust prevention effect. One such method was discovered by changing the side position of the die to change the clearance between the die and punch during semi-cutting to that during finish cutting. In the above-mentioned Patent Document 1, the clearance between the die and punch during semi-cutting is changed to that during finish cutting by changing the side position of the punch. This is done to reduce the step between the semi-cut portion and the finish-cut portion by maintaining the side position of the die. In other words, when changing the side position of the die as described above, it is necessary to reduce the step at the cut end while increasing the length of the plating component remaining.

[0007] The present invention has been made to solve the above-mentioned problems, and one of its objects is to provide a method for manufacturing a metal processed product and a metal processed product that can reduce the step at the cut end while increasing the remaining length of plating components at the cut end after finish cutting.

[0008] In one embodiment, a method for manufacturing a metal processed product according to the present invention is a method for manufacturing a metal processed product using a plated metal sheet having a plating layer on its surface as a raw material, and having a cut end portion along the thickness direction of the raw material, the method comprising: a half-cutting step of using a first die and a first punch to half-cut a first element formed from the raw material in the thickness direction to form a half-cut portion; and a finish-cutting step of using a second die and a second punch to finish-cut the half-cut portion in the same direction as the half-cutting to obtain a metal processed product having a cut end portion, wherein with respect to the half-cutting step: 31-41 (mm) is set to a negative clearance, and for the finish cutting process, the clearance C between the second die and the second punch 32-42 (mm) is set to the positive clearance, and the clearance C between the first die and the first punch 31-41 (mm) to the clearance C between the second die and the second punch 32-42The change in thickness (mm) from the first die to the second die is made by changing the side position from the first die to the second die, and the change distance Md (mm) from the side position of the first die to the side position of the second die satisfies the following formula (b1): Md≦0.25 ... (b1) The clearance C between the second die and the second punch relative to the remaining plate thickness t2 of the half-cut portion corresponds to the distance along the pushing direction of the first die between the connecting position of the cutting edge and the side of the first die and the upper surface of the first punch that contacts the lower surface of the first blank when the first die is pushed in to the bottom dead center 32-42 The ratio (C 32-42 / t2) × 100(%) satisfies the following formula (b3-3): (C 32-42 / t2) × 100 ≦ 25.0 × t2 -1 ... (b3-3)

[0009] In one embodiment, a metal processed product according to the present invention is a metal processed product made from a plated metal sheet having a plating layer on its surface, and having a cut edge extending along the thickness direction of the material, wherein the cut edge has a sag, a shear surface, and a fracture surface, in that order, or a sag and a shear surface, in that order, in the thickness direction, and the shear surface has, in the thickness direction, a first shear surface that is continuous with the sag and a second shear surface that is continuous with the first shear surface, the second shear surface being formed to protrude beyond the first shear surface in a direction perpendicular to the thickness direction, and the amount of protrusion of the second shear surface in the direction perpendicular to the first shear surface is greater than 0 mm and not greater than 0.25 mm, and the ratio L / t1 of the remaining length L of the plating component where the shear surface is covered with the surface plating layer to the sheet thickness t1 of the cut edge is 0.80 or greater, and the ratio Z / t1 of the length Z of the sag in the thickness direction to the sheet thickness t1 of the cut edge is greater than 0 and less than 0.10.

[0010] According to one embodiment of the method for manufacturing a metal processed product and the metal processed product of the present invention, it is possible to reduce the step at the cut end while increasing the remaining length of plating components at the cut end after finish cutting.

[0011] 8 is a perspective view showing an example of a metal processed product 1 manufactured by a method for manufacturing a metal processed product according to an embodiment of the present invention; FIG. 1 is an explanatory view showing a first aspect of a cut end portion in region A of FIG. 1; FIG. 2 is an explanatory view showing a second aspect of a cut end portion in region A of FIG. 1; FIG. 3 is a detailed view of a cross section of the cut end portion of FIG. 2; FIG. 4 is a graph showing an example of a relationship between sag Z and sag X; FIG. 5 is an explanatory view showing a method for manufacturing a metal processed product according to an embodiment of the present invention; FIG. 6 is an explanatory view showing a first die and a first punch used in the half-cutting step of FIG. 6; FIG. 7 is an explanatory view showing a second die and a second punch used in the finish-cutting step of FIG. 6; FIG. 8 is an explanatory view showing an enlarged view of region B of FIG. 8; FIG. 9 is an explanatory view showing a second aspect of the first die and a first punch used in the half-cutting step of FIG. 6; FIG. 10 is an explanatory view showing a second aspect of the second die and a second punch used in the finish-cutting step of FIG. 6; FIG. 11 is an explanatory view showing ductile burrs that may occur during finish cutting; and FIG. 12 is an explanatory view showing uncut defects that may occur during finish cutting. Fig. 18 is a schematic diagram showing an example of a cutting die for manufacturing the processed product of Fig. 14. Fig. 19 is a schematic diagram showing a state in which a material has been punched using the cutting die of Fig. 18. Fig. 20 is a perspective view showing another example of a processed product. D2 The clearance C between the second die and the second punch for the remaining plate thickness of the half-cut portion when the 32-42 The ratio (C 32-42 1 is a graph showing the relationship between the radius of curvature R D2 The clearance C between the second die and the second punch for the remaining plate thickness t2 of the half-cut portion when is less than 1.00 mm 32-42 The ratio (C 32-42 / t2) × 100 and the remaining plate thickness t2.

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to each embodiment, and the components can be modified and embodied without departing from the spirit of the present invention. Furthermore, various inventions can be formed by appropriately combining multiple components disclosed in each embodiment. For example, some components may be omitted from all the components shown in the embodiments. Furthermore, components of different embodiments may be appropriately combined.

[0013] <Regarding the Metal Worked Product> Fig. 1 is a perspective view showing an example of a metal worked product 1 manufactured by a method for manufacturing a metal worked product 1 according to an embodiment of the present invention. The metal worked product 1 shown in Fig. 1 is a motor case made of a plated metal sheet having a plated layer on its surface.

[0014] As shown in FIG. 1 , the metal processed product 1 according to this embodiment has a body portion 10 , a protrusion portion 11 and a flange portion 12 .

[0015] The body 10 has a hollow cylindrical side wall 101 and a top wall 103 formed to cover one end of the side wall 101. The top wall 103 may be called a bottom wall or other name depending on the orientation of the metal processed product 1. The cross-sectional shape of the body 10 of the metal processed product 1 shown in FIG. 1 in the XY plane (the transverse cross-sectional shape of the body 10) is a perfect circle, but the present invention is not limited to this example. The cross-sectional shape of the body 10 in the XY plane may also be other shapes, such as an ellipse or a polygon.

[0016] The protrusion 11 is a protruding body that protrudes outward from the top wall 103 in the central axis direction (Z direction) of the body 10. Note that the protrusion 11 does not necessarily have to be formed, and the top wall 103 may be flat.

[0017] The flange portion 12 is a plate portion that extends from an end portion of the body portion 10 (i.e., the other end of the side wall 101) toward the outside in the radial direction (X and Y directions) of the body portion 10. The shape of the flange portion 12 is arbitrary. The flange portion 12 in this embodiment extends in the radial direction of the body portion 10 over the entire circumferential area of ​​the body portion 10. The flange portion 12 has a plurality of screw holes 121 that are spaced apart from one another in the circumferential direction of the body portion 10. Screws 123 are inserted into the screw holes 121. The metal processed product 1 can be fixed to an attachment object, such as a vehicle body, by fastening it to the attachment object using the screws 123.

[0018] The flange portion 12 according to this embodiment is formed by cutting a flange portion blank (flange portion blank 20 in FIG. 6 ) having an outer diameter larger than the outer diameter of the flange portion 12 that will ultimately be formed on the metal processed product 1. That is, the metal processed product 1 according to this embodiment has a cut end 13 on the outer periphery of the flange portion 12. The cut end 13 extends along the thickness direction of the plated metal sheet that is the raw material.

[0019] Cutting processes include cutting, punching, and drilling. Cutting is a process of cutting an object along a predetermined straight line or curve. Punching is a process of punching a product out of an object. Drilling is a process of punching out a non-product part from an object to obtain a product with an opening. The flange portion 12 shown in FIG. 1 can be obtained by punching out a flange portion base body.

[0020] The base material of the plated metal sheet may be any metal, such as steel, copper, a copper alloy, aluminum, or an aluminum alloy. Typically, the plated metal sheet is a plated steel sheet. The manufacturing method of the metal processed product 1 according to the embodiment of the present invention, which will be described later, is particularly suitable for the case where the base material is steel. This is because steel is prone to rust, and imparting corrosion resistance is a significant advantage.

[0021] The plated steel sheet is, for example, a Zn-based plated steel sheet, an Al-based plated steel sheet, or the like. The plated steel sheet is more preferably a Zn-based plated steel sheet. The Zn-based plating has a sacrificial corrosion protection effect on the base steel sheet. Therefore, corrosion from the exposed portion of the base material on the end surface of the cut end portion 13 can be suppressed, and the corrosion resistance of the manufactured metal member can be further improved. Examples of the Zn-based plating include hot-dip Zn galvannealing, alloyed hot-dip galvannealing, Zn-Ni-based plating, Zn-Al-based plating, Zn-Mg-based plating, and Zn-Al-Mg-based plating.

[0022] The thickness of the plated metal sheet (the thickness of the base metal sheet plus the thickness of the plating layer) is not particularly limited and may be, for example, 0.8 mm or more and 6.0 mm or less, more preferably 2.0 mm or more and 4.5 mm or less.

[0023] When the plating weight of the plated metal sheet is above a certain level, the plating metal is likely to wrap around to the end surface of the cut end 13. By allowing the plating metal to wrap around, the corrosion resistance of the end surface of the cut end 13 can be improved. The preferable lower limit of the plating weight is 30 g / m 2 A more preferable lower limit of the plating coating weight is 45 g / m 2 The preferred upper limit of the plating coating weight is 450 g / m 2 A more preferable upper limit of the plating coating weight is 190 g / m 2 is.

[0024] <Regarding the Cut End of the Workpiece> Next, the cut end 13 of the metal workpiece 1 will be described using Figures 2 to 5. Figures 2 and 3 are explanatory diagrams showing first and second aspects of the cut end 13 in region A of Figure 1. The left side of Figures 2 and 3 is a cross-sectional view of the cut end 13 in the ZX plane of Figure 1, and the right side of Figures 2 and 3 is a front view of the cut end 13 as viewed along the X direction of Figure 1. Figure 4 is a detailed cross-sectional view of the cut end 13 in Figure 2. Figure 5 is a graph showing an example of the relationship between sag Z and sag X. Note that in Figures 2 to 4, the plate thickness direction T of the cut end 13 is assumed to be the same direction as the central axis direction (Z direction) of the metal workpiece 1 shown in Figure 1. Also, Figures 2 and 3 omit the plating layer 13g shown in Figure 4.

[0025] 2, the cut end 13 has a sag 13c, a shear surface 13d, and a burr 13f in the thickness direction T of the cut end 13 from the upper surface 13a to the lower surface 13b. The cut end 13 may further have a fracture surface 13e between the shear surface 13d and the burr 13f. It is preferable that the metal processed product 1 does not have a burr 13f, and the metal processed product 1 according to this embodiment may be a metal processed product 1 that does not have a burr 13f.

[0026] The upper surface 13a is the surface (pressed surface) onto which the cutting edges of the cutting dies (the first die 31 and the second die 32 in FIGS. 7 and 8, etc.) are pressed when cutting the flange portion blank, and the lower surface 13b is the surface from which the cutting edges of the cutting dies emerge when cutting the flange portion blank.

[0027] The sag 13c is a portion of the flange portion element surface that is deformed due to a tensile force acting on the surface of the flange portion element (the plated metal sheet as the raw material) when the cutting edge of the cutting die is pressed into the flange portion element. The sag 13c typically appears as a smooth surface with a curvature at the cut end 13. In this specification, the dimension of the sag 13c in the thickness direction T of the cut end 13 is referred to as "sag Z," and the dimension of the sag 13c in a planar direction perpendicular to the thickness direction T is referred to as "sag X."

[0028] The sheared surface 13d is a surface where the flange portion element is sheared by the cutting edge of the cutting die. The sheared surface 13d is adjacent to the sag 13c in the thickness direction T of the cut end 13. The sheared surface 13d typically appears as a smooth surface at the cut end 13. The sheared surface 13d may have a metallic luster because it is created by rubbing against the side surface of the cutting die when a compressive (pressure) force is applied after the cutting die comes into contact with the workpiece and bites into the workpiece. Fine streak-like sliding scratches may be seen on the sheared surface 13d in the thickness direction T.

[0029] The fracture surface 13e is a surface formed by the intersection of cracks generated in the flange portion blank from the cutting edge of the cutting die. The fracture surface 13e may be adjacent to the shear surface 13d in the plate thickness direction T of the flange portion 12. The fracture surface 13e typically appears as a dull, rough surface at the cut end 13. The fracture surface 13e may have an inclination corresponding to the gap (clearance) of the cutting die.

[0030] The burrs 13f are portions of the flange element that are stretched or torn off when the fractured surfaces 13e are formed. The burrs 13f are adjacent to the fractured surfaces 13e in the thickness direction T of the flange 12.

[0031] Methods for identifying the sagging 13c, shear surface 13d, fracture surface 13e, and burrs 13f in the cut end portion 13 (methods for measuring the length of each) include, for example, observing and measuring the shape profile of the cut end portion 13 from the appearance using a microscope or a contrast tracer based on the above characteristics.

[0032] In this embodiment, the shear surface 13d has a first shear surface 13d1 that is continuous with the sag 13c in the thickness direction T, and a second shear surface 13d2 that is continuous with the first shear surface 13d1. The lower end of the second shear surface 13d2 may be continuous with the fracture surface 13e. The second shear surface 13d2 is formed to protrude from the first shear surface 13d1 in a direction perpendicular to the thickness direction T (the X-axis direction in the figure), and the protrusion amount PA of the second shear surface 13d2 in the direction perpendicular to the first shear surface 13d1 is greater than 0 mm and less than or equal to 0.25 mm. In other words, a step 13d3 having a height greater than 0 mm and less than or equal to 0.25 mm may be formed between the first shear surface 13d1 and the second shear surface 13d2. By limiting the protrusion amount PA of the second shear surface 13d2 to 0.25 mm or less, interference with other components can be easily avoided. The protrusion amount PA may be 0.20 mm or less, or 0.15 mm or less. When the cut end portion 13 is viewed from the front as shown on the right side of Figure 2, a boundary line may be visible between the first shear surface 13d1 and the second shear surface 13d2.

[0033] 2 shows a state in which the first shear plane 13d1 extends substantially in the plate thickness direction T. This occurs when the constraint by the first plate holder 51 (see FIG. 7, etc.) is sufficiently strong during the half-cutting step described later, or when the clearance C during the half-cutting step is large enough. 31-41 is large (even in the negative clearance | C 31-41 On the other hand, FIG. 3 shows a state in which the first shear plane 13d1 extends at an angle to the plate thickness direction T. This is because the constraint by the first plate holder 51 is weak during the half-cutting process, or the clearance C during the half-cutting process is small. 31-41 is small (even in the negative clearance | C 31-41 This shows a state that tends to occur when the constraint by the first plate holder 51 during the semi-cutting step is weak or the clearance C 31-41 When the shear plane 13d1 is small, the left side of the flange portion 12 in FIG. 7 bounces up due to the compressive stress during the half-cutting process, and in the finish-cutting process that follows the half-cutting process, the flange portion 12 is pressed with the second plate holder 52 to make it flat before the finish-cutting is performed, so the first shear plane 13d1 tends to be inclined with respect to the plate thickness direction T.

[0034] The protrusion amount PA may be the largest distance between the end face of the first shearing surface 13d1 and the end face of the second shearing surface 13d2 in a direction perpendicular to the thickness direction T. In an embodiment in which the first shearing surface 13d1 extends in the thickness direction T as shown in Fig. 2, the protrusion amount PA may be the distance between the end face of the first shearing surface 13d1 and the end face of the second shearing surface 13d2 in a direction perpendicular to the thickness direction T. In an embodiment in which the first shearing surface 13d1 extends at an angle with respect to the thickness direction T as shown in Fig. 3, the protrusion amount PA may be the distance between the upper end position of the first shearing surface 13d1 (the connection position between the sag 13c and the first shearing surface 13d1) and the end face of the second shearing surface 13d2 in a direction perpendicular to the thickness direction T.

[0035] In the metal processed product 1 of this embodiment, as particularly shown in Figure 4, a plating layer 13g extends from the upper surface 13a of the cut end portion 13 to the sheared surface 13d. When the cutting die's cutting edge bites into the flange body, the plating layer 13g is stretched by the cutting die and extends to the sheared surface 13d. This extension of the plating layer 13g coats at least a portion of the sheared surface 13d with the plating layer 13g, thereby suppressing the occurrence of red rust in the portion coated with the plating layer 13g. Furthermore, when the plating layer 13g is a Zn-based plating layer, the sacrificial anticorrosion effect of the Zn-based plating layer also suppresses the occurrence of red rust in the vicinity of the portion coated with the plating layer 13g.

[0036] The first shear surface 13d1 is generated in the half-cutting step, and the second shear surface 13d2 is generated in the finish cutting step after the half-cutting step. Because the finish cutting is performed with a positive clearance, as described below, the compressive stress acting on the cutting edge of the second die 32 used in the finish cutting is small. Therefore, less of the plating layer 13g wraps around the second shear surface 13d2 than around the first shear surface 13d1. Therefore, from the perspective of wraparound of the plating layer 13g, the larger the ratio of the first shear surface 13d1 to the second shear surface 13d2 (the length of the first shear surface 13d1 in the sheet thickness direction T / the length of the second shear surface 13d2 in the sheet thickness direction T), the more preferable it is.

[0037] In the metal processed product 1 of this embodiment, the length L1 of the plating layer 13g, which extends from the upper surface 13a of the cut end 13 to the sag 13c and covers at least a portion of the sheared surface 13d, is 0.80 times or more the thickness t1 of the cut end 13 of the metal processed product 1. That is, the ratio L1 / t1 of the remaining plating component length L, where the sheared surface 13d is covered by the plating layer 13g on the surface of the plated metal sheet, to the thickness t1 of the cut end 13 is 0.80 or more. L1 / t1 may also be 0.85 or more. The length L1 of the plating layer 13g or the remaining plating component length L1 can also be considered as the distance between the upper surface 13a of the cut end 13 and the lower end of the plating layer 13g in the thickness direction T of the cut end 13. The thickness t1 of the cut end 13 can also be considered as the distance between the upper surface 13a and the lower surface 13b of the cut end 13 in the thickness direction T of the cut end 13. More specifically, the thickness t1 of the cut end 13 may be the distance between the upper surface 13a and the lower surface 13b at a position not affected by the sagging 13c (a position sufficiently distant from the outer edge of the cut end 13). The thickness t1 of the cut end 13 is equal to the thickness of the flange portion 12 shown in FIG.

[0038] In the metal processed product 1 of this embodiment, the ratio Z / t1 of the length Z of the sag 13c in the thickness direction T to the thickness t1 of the cut end portion 13 is greater than 0 and less than 0.10. In order to ensure a flat portion around the screw 123, it is desirable to make the sag X as small as possible. The sag Z and the sag X are correlated with each other. Therefore, in terms of the sag Z, which is easy to measure, it is preferable that the ratio Z / t1 is less than 0.10. The thickness t1 of the cut end portion 13 is also equal to the thickness of the flange portion element 20. A smaller sag Z is preferable, and the ratio Z / t1 may be less than 0.08, less than 0.06, or less than 0.04.

[0039] Figure 5 shows an example of the relationship between sag Z and sag X of the cut end 13 when punching is performed in a single process. Figure 5 shows the relationship between sag Z and sag X of the cut end 13 of the product when punching is performed by imparting a radius of curvature of 0.01 to 0.30 in relation to the plate thickness of the flange portion blank to the cutting edge of the cutting die that is pressed into the flange portion blank and setting the clearance of the cutting die to 0.01 to 0.20 times the plate thickness. As shown in Figure 5, when punching is performed in a single process, the sag X that appears in the planar direction is about 3 to 4 times the size of the sag Z in the plate thickness direction.

[0040] Furthermore, the length of the burrs 13f generated on the lower side of the cut end portion 13 of the metal workpiece 1 may be less than 0.2 mm. The burrs 13f can cause dents, electrical short circuits, etc. By making the length of the burrs 13f less than 0.2 mm and minimizing the amount of burrs 13f remaining on the metal workpiece 1, the occurrence of dents, electrical short circuits, etc. can be suppressed. It is more preferable that the length of the burrs 13f be less than 0.1 mm. It is most preferable that the length of the burrs 13f be 0 mm, i.e., that there are no burrs 13f on the metal workpiece 1.

[0041] Therefore, in the method for manufacturing a processed product according to this embodiment, the plated steel sheet is cut not in a single step but in two steps, a semi-cutting step and a finish-cutting step. This allows a larger amount of the plating layer 13g to bend around the shear surface 13d while suppressing the sagging 13c of the cut end 13. The method for manufacturing a processed product according to this embodiment will be described below.

[0042] <Regarding the manufacturing method of the metal processed product 1> Next, Fig. 6 is an explanatory diagram showing a manufacturing method of the metal processed product 1 according to an embodiment of the present invention. As shown in Fig. 6, the manufacturing method of the metal processed product 1 according to this embodiment includes a preparation step, a semi-cutting step, and a finish cutting step.

[0043] The preparation step is a step of preparing a first element body 2. The first element body 2 can be obtained by performing a forming process, such as drawing, on a flat plated metal sheet. That is, the first element body 2 is made of a plated metal sheet, just like the metal processed product 1. The first element body 2 includes a flange portion element body 20 having an outer diameter larger than that of the flange portion 12 shown in FIG. 1. The flange portion element body 20 may have a circular or non-circular outer shape in a plan view. The first element body 2 may have a shape similar to that of the metal processed product 1, except for the flange portion element body 20. The preparation step does not necessarily involve forming a plated metal strip. An element body processed by a third party by some method may be obtained. The flange portion element body 20 of this embodiment constitutes the flat portion to be cut, including the portion that will become the cut end portion 13.

[0044] The half-cutting process is a process in which the first element 2 is half-cut in the plate thickness direction to form a half-cut portion. In the half-cutting process, the flange portion element 20 (portion to be cut) is half-cut. Half-cutting is a process in which the flange portion element 20 is cut partway through in the plate thickness direction of the flange portion element 20. Here, the smooth surface smoothed by the side surface of the die used for half-cutting (side surface 31a of the first die 31 in Figure 7, etc.) becomes the first shear surface 13d1. When the flange portion element 20 of the first element 2 is half-cut, the removed portion 20a, which will ultimately be outside the product, is cut partway from the flange portion element 20.

[0045] The finish-cutting process is a process in which the half-cut portion is finish-cut in the same direction as the half-cutting process to obtain a metal processed product 1 having a cut end portion 13. In the finish-cutting process, the removed portion 20a of the flange portion blank 20 is cut and separated from the flange portion blank 20. The flange portion 12 is formed by cutting the removed portion 20a. The smoothed surface smoothed by the side surface of the die used for the finish-cutting (side surface 32a of the second die 32 in FIG. 8 , etc.) becomes the second shear surface 13d2. That is, in the manufacturing method of the metal processed product 1 according to this embodiment, the metal processed product 1 is obtained from the first blank 2 prepared in the preparation process through the half-cutting process and the finish-cutting process. The screw holes 121 of the metal processed product 1 shown in FIG. 1 may be formed in the flange portion blank 20 at the stage of the first blank 2, or may be formed in the flange portion 12 after the finish-cutting process.

[0046] In the semi-cutting step and the finish-cutting step of the method for manufacturing the metal processed product 1 according to this embodiment, the flange portion blank 20 is machined using a die and a punch. The semi-cutting step and the finish-cutting step will be described in detail below. The cutting edges of the die and the punch are sometimes referred to as "shoulders."

[0047] In the following description, for convenience, the molds used to obtain the metal processed product 1 will be referred to as the pressing die and the pressed-in mold as the punch. The pressing die may be positioned above or below the first element body 2. Even when they move horizontally, the pressing die is referred to as the die and the pressed-in mold as the punch. For example, the metal processed product 1 shown in FIG. 2 was cut using the upper pressing die. If the lower die were used as the pressing die, i.e., the lower die were used as the die, the cut end 13 of the metal processed product 1 would be the opposite of that shown in FIG. 2 , with the sag 13c located at the bottom of the cut end 13 and a shear surface 13d formed above it. If it is unclear which of the upper (or left) or lower (or right) dies will serve as the die and the punch, the cut end 13 can be observed after actual cutting, and the die that presses the surface on the side where the sag 13c is located can be referred to as the die, and the die that presses the opposite surface can be referred to as the punch. In any case, as described above, the upper surface 13a of the cut end portion 13 is defined as the surface on the side where the cutting edge of the die is pressed in during cutting of the flange portion body 20, i.e., the surface on the side where the sag 13c is located. Also, the lower surface 13b of the cut end portion 13 is defined as the surface on the side where the cutting edge of the die comes out during cutting of the flange portion body 20.

[0048] <a. Half-cutting step> Next, Fig. 7 is an explanatory diagram showing the first die 31 and the first punch 41 used in the half-cutting step of Fig. 6. The upper side of Fig. 7 shows the state immediately before the half-cutting process, and the lower side of Fig. 7 shows the state immediately after the half-cutting process.

[0049] As shown in Figure 7, in the half-cutting step of the method for manufacturing a metal processed product 1 according to this embodiment, the first blank 2 is half-cut in the plate thickness direction using a first die 31 and a first punch 41 to form the half-cut portion 21. Figure 7 shows one mode of half-cutting processing, in which the flange portion blank 20 of the first blank 2 held between the first punch 41 and the first plate holder 51 is half-cut (half-punched). The first die 31 constitutes a cutting mold that is pressed into the flange portion blank 20 during half-cutting. In this embodiment, the mold that presses the portion of the flange portion blank 20 that will become the flange portion 12 is the first punch 41, and the mold that presses the removed portion 20a is the first die 31.

[0050] Clearance C between the first die 31 and the first punch 41 31-41 (mm) is the negative clearance. Here, the clearance C 31-41 represents the gap between the first die 31 and the first punch 41, and specifically, as shown in FIG. 7, is represented by the distance between the side surface 31a of the first die 31 and the side surface 41a of the first punch 41. In the state where there is no clearance (i.e., C 31-41 When viewed from the pushing direction of the first die 31 (i.e., the plate thickness direction of the flange portion 12, the Z direction), the clearance when the first die 31 and the first punch 41 are separated from each other is referred to as a positive clearance, and the clearance when the first die 31 and the first punch 41 are partially overlapping is referred to as a negative clearance. In this specification, regarding the clearance between the die and the punch, a positive clearance is represented by a positive value, and a negative clearance is represented by a negative value.

[0051] As shown in Figure 7, the first die 31 and the first punch 41 that cut the first element body 2 in half are arranged so that the first die 31 and the first punch 41 partially overlap when viewed from the pushing direction of the first die 31. 31-41 If the clearance C is set to a positive value, cracks generated from the cutting edges of the first die 31 and the first punch 41 may meet, as in a single punching operation, and the removed portion 20a may be completely cut off from the flange portion body 20. In addition, the sagging 13c of the cut end 13 will increase. 31-41By making the clearance a negative clearance, it is possible to prevent the removed portion 20a from being completely cut off from the flange portion body 20 in the half-cutting step, and to reduce the sagging 13c.

[0052] Also, clearance C 31-41 By making the clearance between the first die 31 and the first punch 41 negative, large hydrostatic stress is generated in the region sandwiched between the first die 31 and the first punch 41. Therefore, the proportion of tensile stress generated between the material that will become scrap (i.e., the removed portion 20a) after cutting and the flange material that will become the flange portion 12 is reduced in the stress generated when the first die 31 is pressed into the flange portion element 20. As a result, the material that will become scrap after cutting and that contacts the tip of the cutting edge of the first die 31 is more likely to flow from the tip of the cutting edge of the first die 31 toward the side surface 31a of the first die 31, thereby increasing the spread of the plating layer 13g around the sheared surface 13d. Furthermore, the reduction in the proportion of tensile stress increases compressive stress, and the material that would normally flow toward the scrap side is pushed back toward the flange portion 12. As a result, the material is also filled in the portion that will become sagging 13c after cutting, thereby reducing the sagging 13c.

[0053] In the direction in which the first die 31 and the first punch 41 are adjacent to each other (the X direction in FIG. 7 ), the shorter the length of the material that will become scrap after cutting is, the more likely the material is to flow from the tip of the cutting edge of the first die 31 toward the side surface 31 a of the first die 31. For this reason, it is preferable to perform half-cutting by positioning the first die 31 so that the side surface 31 a of the first die 31 is located within a range from the end of the flange portion element 20 that is not more than twice the plate thickness t1 of the flange portion element 20 (i.e., the flange portion 12).

[0054] Clearance C between the first die 31 and the first punch 41 31-41 It is preferable that the thickness (mm) satisfies the following formula (a1): −0.35×t1≦C 31-41 ≦−0.0125×t1 (a1) Here, t1 is the plate thickness (mm) of the portion to be partially cut of the first element body 2. In this embodiment, the portion to be partially cut of the first element body 2 is the flange element body 20.

[0055] Clearance C31-41 is less than or equal to -0.0125 times the plate thickness t1 of the flange portion element 20, large hydrostatic stress occurs in the region sandwiched between the first die 31 and the first punch 41, and the proportion of tensile stress decreases. As a result, cracks do not occur during half-cutting, causing complete cutting, and large fracture surfaces do not occur, so it is possible to prevent the removed portion 20a from being completely cut off from the flange portion element 20 in the half-cutting step. On the other hand, if the clearance C 31-41 is equal to or greater than -0.35 times the plate thickness t1 of the flange portion element 20, the forming load required for half-cutting will not increase and will not exceed the press capacity. Therefore, the burden on the die is small, and it is possible to suppress a decrease in the die life. 31-41 is more preferably set to be equal to or less than -0.10 times or equal to or less than -0.15 times the plate thickness t1 of the flange portion element 20. 31-41 may be set to be −0.30 times or more or −0.25 times or more the plate thickness t1 of the flange portion element 20.

[0056] The cutting edge of the first die 31 has a radius of curvature R D1 (mm), and the cutting edge of the first die 31 has a radius of curvature R D1 It is preferable that the thickness (mm) satisfies the following formula (a2): 0.10×t1≦R D1 ≦1.50...(a2)

[0057] As shown in FIG. 7, the cutting edge of the first punch 41 has a radius of curvature R P1 (mm), and the radius of curvature of the cutting edge of the first punch 41 is R P1 It is preferable that the thickness (mm) satisfies the following formula (a3): 0.10×t1≦R P1 ≦3.00...(a3)

[0058] radius of curvature R D1 , R P1 is 0.10 times or more the plate thickness t1, a large hydrostatic stress is generated under a negative clearance without scraping off the plating layer 13g, and the material to become scrap (i.e., the removed portion 20a) directly below the first die 31 can flow from the cutting edge of the first die 31 to the side surface 31a of the first die 31. D1is 0.10 times the plate thickness t1 or more, the first die 31 can be pressed deeper into the flange portion element 20, and the material that will become scrap (i.e., the removed portion 20a) directly below the first die can flow from the cutting edge of the first die 31 toward the side surface 31a of the first die 31. This flow reduces the proportion of tensile stress that occurs between the material that will become scrap after cutting and the flange material that will become the flange portion 12, among the stresses that occur when the first die 31 is pressed into the flange portion element 20. As a result, the plating layer 13g can be caused to flow around the sheared surface 13d.

[0059] On the other hand, the radius of curvature R D1 , R P1 If these distances are set to 1.50 mm or less and 3.00 mm or less, respectively, less material is present at the cutting edge of the first die 31 during semi-cutting, and the generation of fracture surfaces 13e can be reduced during the subsequent finish cutting.

[0060] Furthermore, by making the cutting edges of the first die 31 and the first punch 41 rounded, it is possible to increase the amount of cutting of the flange portion blank 20 in the half-cutting step, compared to when only one of the cutting edges of the first die 31 or the first punch 41 is rounded. In other words, by making the cutting edges of the first die 31 and the first punch 41 rounded, it is possible to reduce the remaining plate thickness t2 (mm) of the half-cut portion 21 of the first blank 2, compared to when only one of the cutting edges of the first die 31 or the first punch 41 is rounded. The remaining thickness t2 of the half-cut portion 21 of the first base body 2 (flange portion base body 20) corresponds to the distance along the pushing direction of the first die 31 between the connection position between the cutting edge of the first die 31 and the side surface 31a and the upper surface 41b of the first punch 41 that contacts the lower surface 2b of the first base body 2 when the first die 31 is pushed down to the bottom dead center as shown in the lower side of Figure 7, and can also be said to be the remaining thickness of the removed portion 20a in the half-cut portion 21.

[0061] If only the cutting edge of the first die 31 is rounded, the cutting edge of the first die 31 will come into contact with the cutting edge of the first punch 41 if the push-in amount D of the first die 31 is set to be equal to or greater than the thickness t1 of the flange portion 12. In this case, the push-in amount D of the first die 31 cannot be set to be equal to or greater than the thickness t1 of the flange portion 12. Note that, as shown in FIG. 7 , the push-in amount D is the amount of movement of the first die 31 from the position where the first die 31 comes into contact with the top surface of the flange portion blank 20 of the first blank 2 to the position where the push-in of the first die 31 stops (hereinafter, this position will also be referred to as the "bottom dead center").

[0062] On the other hand, if the cutting edges of the first die 31 and the first punch 41 are rounded, as shown in FIG. 7 , the amount by which the first die 31 can be pressed down until its cutting edge contacts the cutting edge of the first punch 41 increases. Therefore, by rounding both the cutting edges of the first die 31 and the first punch 41, the pressing amount D of the first die 31 can be set to be equal to or greater than the plate thickness t1 of the flange portion 12, thereby increasing the amount of cutting of the flange portion element 20 in the half-cutting process and increasing the proportion of the sheared surface 13d in the cut end portion 13. This allows the plating layer 13g to extend more around the sheared surface 13d, thereby increasing the proportion of the cut end portion 13 covered by the plating layer 13g. Furthermore, the reduction in the remaining plate thickness t2 reduces the amount of cutting in the finish-cutting process, thereby avoiding a situation in which no plating layer remains in part of the finish-cut portion.

[0063] It is preferable that the remaining thickness t2 (mm) of the half-cut portion 21 satisfies the following formula (a4): 0.20≦t2≦1.80 (a4)

[0064] By setting the remaining sheet thickness t2 to 1.80 mm or less, the plating layer 13g can be sufficiently wrapped around the sheared surface 13d in the subsequent finish cutting process, thereby improving the corrosion resistance of the cut surface. The upper limit of the remaining sheet thickness t2 is preferably 1.40 mm, more preferably 1.30 mm.

[0065] On the other hand, if the remaining plate thickness t2 is 0.20 mm or more, it is possible to prevent a portion from being cut off during the semi-cutting process or a large burr from being generated due to a portion not being cut off after the finish cutting process. P1-D1 This can ensure that the gap C is large enough to prevent cracks from occurring during partial cutting, resulting in partial complete cutting. P1-D1 is the minimum value of the gap between the first die 31 and the first punch 41 at the bottom dead center. The lower limit of the remaining sheet thickness t2 is preferably 0.40 mm, and more preferably 0.50 mm.

[0066] <b. Finish Cutting Step> Next, Fig. 8 is an explanatory diagram showing the second die 32 and the second punch 42 used in the finish cutting step of Fig. 6, and Fig. 9 is an explanatory diagram showing an enlarged view of region B of Fig. 8. The upper side of Fig. 8 shows the state immediately before the finish cutting process, and the lower side of Fig. 8 shows the state immediately after the finish cutting process.

[0067] In the finish cutting step, as shown in Fig. 8, the flange portion element 20 having the half-cut portion 21 is finish-cut using a second die 32 and a second punch 42. Fig. 8 shows, as one mode of finish cutting, a mode in which the flange portion 12 is punched out from the flange portion element 20 held between the second punch 42 and the second plate holder 52. The second die 32 constitutes a cutting mold that is pressed into the flange portion element 20 during finish cutting. In this embodiment, the mold that presses the portion of the flange portion element 20 that will become the flange portion 12 is the second punch 42, and the mold that presses the removed portion 20a is the second die 32.

[0068] The finish cutting in this embodiment is performed in the same direction as the half cutting. That is, when the first die 31 is pressed into the flange portion element 20 from the upper surface side of the flange portion element 20 in the half cutting as shown in Fig. 7, the second die 32 is also pressed into the flange portion element 20 from the upper surface side of the flange portion element 20 in the finish cutting as shown in Fig. 8. This separates the removed portion 20a from the flange portion element 20, yielding the metal processed product 1 having the flange portion 12 and the cut end portion 13.

[0069] Clearance C between the second die 32 and the second punch 4232-42 (mm) is the positive clearance. Clearance C 32-42 is expressed as the distance between the side surface 32 a of the second die 32 and the side surface 42 a of the second punch 42. Here, as in the half-cutting process, the clearance when the second die 32 and the second punch 42 are separated from each other is called a positive clearance, and the clearance when the second die 32 and the second punch 42 are partially overlapping each other is called a negative clearance.

[0070] In the finish cutting according to the present embodiment, the clearance C between the first die 31 and the first punch 41 in the semi-cutting step is 31-41 (mm) to the clearance C between the second die 32 and the second punch 42 32-42 The change to the side distance (mm) is performed by changing the side position from the first die 31 to the second die 32, and the change distance Md (mm) from the side position of the first die 31 to the side position of the second die 32 satisfies the following formula (b1): Md≦0.25 (b1)

[0071] The change in the side position from the first die 31 to the second die 32 can be synonymous with the change in diameter from the first die 31 to the second die 32. From the above formula (b1), the diameter D of the first die 31 31 and the diameter D of the second die 32 32 The relationship between the distance D and the thickness D may satisfy the following formula (b1)': 0.5 mm ≧ |D 32 -D 31 | ... (b1)'

[0072] When the cut end 13 is formed on the outer periphery of the metal workpiece 1, the inner diameter of the second die 32 is set to be equal to or larger than the inner diameter of the first die 31, and when the cut end 13 is formed on the inner periphery of the metal workpiece 1, the outer diameter of the second die 32 is set to be equal to or smaller than the outer diameter of the first die 31. 31 , D 32 refers to the inner diameter of the first die 31 and the second die 32 when the cut end 13 is formed on the outer periphery of the metal workpiece 1, and refers to the outer diameter of the first die 31 and the second die 32 when the cut end 13 is formed on the inner periphery of the metal workpiece 1.

[0073] The change of the clearance by changing the side surface position from the first die 31 to the second die 32 means that the position of the side surface 42a of the second punch 42 is set to the position of the side surface 31a of the first die 31 at the time of half-cutting (the position of the first shear surface 13d1), and the side surface 32a of the second die 32 is set to the position of the side surface 31a of the first die 31 at the time of half-cutting (the position of the first shear surface 13d1). 32-42 It can be said that the finish cutting is performed in a state where the cutting edge is spaced apart from the first shear surface 13d1 by 1 mm.

[0074] 9A, the clearance is changed by changing the side position from the first die 31 to the second die 32, and the side surface 32a of the second die 32 has a clearance C. 32-42 9(b) shows a state in which the side surface 32a of the second die 32 is in contact with the first shearing surface 13d1 by a distance D (mm) from the first shearing surface 13d1. On the other hand, FIG. 9(b) shows a state in which the clearance is changed by changing the side surface position from the first punch 41 to the second punch 42, and the side surface 32a of the second die 32 is in contact with the first shearing surface 13d1. 32 is the diameter D of the first die 31 31 , and the positional relationship between the second die 32 and the first element body 2 is the same as the positional relationship between the first die 31 and the first element body 2.

[0075] As described above, in the half-cutting step, the clearance C between the first die 31 and the first punch 41 31-41 Since the clearance C (mm) is set as a negative clearance, when the first die 31 is pressed down to the bottom dead center, the point where the first die 31 and the first die 32 are closest to each other, i.e., the point where the thickness of the half-cut portion 21 is the thinnest, is located between the extension of the side surface 31a of the first die 31 and the extension of the side surface 41a of the first punch 41. As shown in FIG. 9A, the side surface 32a of the second die 32 is spaced apart from the clearance C 32-42 9(b), the thickness t3 of the half-cut portion 21 on the extension of the side surface 32a of the second die 32 is thinner than when the side surface 32a of the second die 32 is in contact with the first shearing surface 13d1. The thickness t3 corresponds to the length for performing the finish cut, and the thinner the thickness t3, the longer the first shearing surface 13d1 can be left, and the longer the remaining length L of the plating component can be.

[0076] Change distance Md or diameter D of first die 31 31 and the diameter D of the second die 32 32 If the absolute value of the difference between the first die 31 and the second die 32 is too large, cutting may not be completed in part in the finish cutting process, resulting in an uncut portion. Even if cutting is possible, an excessive step 13d3 is likely to occur on the end face of the cut end portion 13 after finish cutting. By setting the change distance Md from the side position of the first die 31 to the side position of the second die 32 to 0.25 mm or less (in other words, the diameter D of the first die 31 31 and the diameter D of the second die 32 32 By setting the absolute value of the difference between the first sheared surface 13d1 and the second sheared surface 13d2 to 0.50 mm or less, the occurrence of uncut portions can be suppressed and the step 13d3 between the first sheared surface 13d1 and the second sheared surface 13d2 can be set to 0.25 mm or less. The change distance Md is preferably 0.088 mm or less, and more preferably 0.063 mm or less. The absolute value of the difference is preferably 0.175 mm or less, and more preferably 0.125 mm or less.

[0077] The cutting edge of the second die 32 has a predetermined radius of curvature R D2 As shown in FIG. 15, the second die 32 is pressed into the part of the flange portion body 20 where the finish cutting is to be performed, so the cutting edge of the second die 32 is formed into an R shape having a radius of curvature R D2 The radius of curvature R D2 It is preferable that R (mm) satisfies the following formula (b2): 0.20≦R D2 ≦1.20...(b2)

[0078] R D2 If R is too small, there is a risk that the plating layer 13g that has reached the sheared surface 13d may be scraped off. D2 is preferably 0.20 mm or more. D2 The lower limit of R is more preferably 0.25 mm, and even more preferably 0.30 mm. D2 If R is too large, the cutting edge of the second die 32 will not be able to bite into the workpiece sufficiently during finish cutting (finish punching), increasing the ductility of the material and making it more likely that ductile burrs 14 (see FIG. 12) will be produced. D2is preferably 1.20 mm or less. D2 The upper limit is more preferably 1.00 mm, and even more preferably 0.80 mm.

[0079] The cutting edge of the second punch 42 is rectangular and not rounded, as shown in Fig. 8. In this case, the cutting edge of the second punch 42 may have a radius of curvature of less than 0.25 mm, less than 0.15 mm, less than 0.10 mm, or less than 0.05 mm. Alternatively, the radius of curvature of the cutting edge of the second punch 42 may be less than 0.10 times the plate thickness t1 of the flange portion element 20 of the first element 2, and may be less than 0.06 times, less than 0.04 times, or less than 0.02 times, as necessary.

[0080] <c. Second embodiment of half-cutting step and finish-cutting step> Next, FIG. 10 is an explanatory diagram showing a second embodiment of the first die 31 and the first punch 41 used in the half-cutting step of FIG. 6, and FIG. 11 is an explanatory diagram showing a second embodiment of the second die 32 and the second punch 42 used in the finish-cutting step of FIG. 6.

[0081] 10 shows a half-cutting mode in which the indentation amount D is smaller than that in FIG. 7. The smaller indentation amount D increases the remaining thickness t2 of the plate to be cut in the finish cut. The increase in the remaining thickness t2 tends to increase the length of the second shear surface 13d2.

[0082] Here, the inventors conducted experiments in which the plate thickness t1 of the flange portion 12 on which the cut end portion 13 was formed, the cutting conditions, the surface treatment conditions, etc. were changed over various ranges, and the occurrence of ductile burrs 14 (see FIG. 12) and uncut defects 15 (see FIG. 13) during finish cutting was investigated, as well as the remaining length L of the plating component and the step 13d3 of the cut end portion 13.

[0083] The ductile burr 14 is formed by thinly stretching the material without cutting it during the finish cutting. The ductile burr 14 is formed by the clearance C between the second die 32 and the second punch 42 during the finish cutting with respect to the remaining thickness t2 of the half-cut portion 21 formed by the half-cutting. 32-42The uncut defect 15 is a partial uncut portion that generates a large burr, and the remaining thickness t2 of the half-cut portion 21 formed by half-cutting is too small. 32-42 The size of the step 13d3 of the cut end 13 corresponds to the amount of protrusion PA (see FIG. 2) of the second sheared surface 13d2 in the direction perpendicular to the first sheared surface 13d1.

[0084] As a result, the clearance C between the second die 32 and the second punch 42 with respect to the remaining plate thickness t2 of the half-cut portion 21 is 32-42 The ratio (C 32-42 / t2) × 100(%) satisfies the following formula (b3-3), it has been found that the step 13d3 of the cut end 13 can be suppressed while lengthening the remaining length L of the plating component. 32-42 / t2) × 100(%) satisfies the following formula (b3-3): (C 32-42 / t2) × 100 ≦ 25.0 × t2 -1 ... (b3-3)

[0085] In addition, the ratio (C 32-42 / t2) × 100 (%) is the radius of curvature R of the second die 32 D2 It has been found that the occurrence of ductile burrs 14 and uncut defects 15 during finish cutting can be suppressed by satisfying the following formulas (b3-1), (b3-2), and (b3-4) according to the above.

[0086] That is, in the finish cutting of this embodiment, the ratio (C 32-42 / t2) × 100 (%) is the radius of curvature R D2 When is 1.00 mm or more, it is preferable to satisfy the following formulas (b3-1) and (b3-2): 32-42 / t2) × 100 ≥ 7.0 × t2 3 -11.0 x t2 2 +4.9t2+1.7...(b3-1) (C 32-42 / t2) × 100 ≦ 7.8 × t2 2 -0.6×t2+18.0...(b3-2)

[0087] In addition, the ratio (C 32-42 / t2) × 100 (%) is the radius of curvature R D2 When is less than 1.00 mm, it is preferable to satisfy the following formulas (b3-4) and (b3-2): 32-42 / t2)×100≧2.3 ...(b3-4) (C 32-42 / t2) × 100 ≦ 7.8 × t2 2 -0.6×t2+18.0...(b3-2)

[0088] Ratio (C 32-42 When the value of (t2)×100(%) satisfies the formula (b3-1) or (b3-4), the occurrence of ductile burrs 14 can be suppressed, and when the value of (t2)×100(%) satisfies the formula (b3-2), the occurrence of uncut defects 15 can be suppressed.

[0089] As shown in the above formula (b2), the radius of curvature R of the second die 32 in this embodiment D2 The radius of curvature R is 0.20 mm or more and 1.20 mm or less. D2 When the radius of curvature R is 1.00 mm or more D2 is 1.00 mm or more and 1.20 mm or less, and the radius of curvature R D2 When the radius of curvature R is less than 1.00 mm D2 is 0.20 mm or more and less than 1.00 mm.

[0090] <Examples of Processed Product> In the above embodiment, the metal processed product 1 is described as a motor case as shown in Fig. 1, but the metal processed product 1 manufactured by the processed product manufacturing method according to this embodiment may be any article made from a plated metal sheet and having a cut end portion 13. Examples of the metal processed product 1 include plate materials, drawn products having flange portions 12, burred products having flange portions 12, bulged products having flange portions 12, bent products, and punched products such as various washers, plates, gears, and springs.

[0091] The metal workpiece 1 may be, for example, a circular flat washer 900 as shown in Fig. 14 . The metal workpiece 1 may also be, for example, a flat washer 910A, 910B, or 910C having teeth 911 as shown in Fig. 15 . Alternatively, the metal workpiece 1 may be, for example, a corrugated circular disc spring 920 as shown in Fig. 16 . The disc spring 920 in Fig. 16 may be manufactured by corrugating the flat washer 900 shown in Fig. 14 . Furthermore, the metal workpiece 1 may be, for example, a disc spring 930 having teeth 931 as shown in Fig. 17 .

[0092] When the metal processed product 1 is an annular plate member such as those shown in FIGS. 14 to 17, the outer and inner peripheries thereof become the cut end portions 13.

[0093] For example, in order to cover the sheared surfaces of the inner and outer peripheral surfaces of the flat washer 900 shown in Fig. 14 with a plating layer, cutting dies such as those shown in Fig. 18 and Fig. 19 may be used. Fig. 18 is a schematic diagram showing an example of a cutting die for processing the flat washer 900. Fig. 19 is a schematic diagram showing the state after blanking the element 9 using the cutting die of Fig. 18.

[0094] The cutting die shown in FIG. 18 is a die for manufacturing an annular metal workpiece 90 such as a flat washer 900, and includes a hollow cylindrical die (hereinafter referred to as the "outer die") 61, a columnar die (hereinafter referred to as the "inner die") 63, and a hollow cylindrical punch 65 that supports a disk-shaped blank 9 (see FIG. 19). The outer die 61, the inner die 63, and the punch 65 are arranged opposite each other, and the blank 9 is cut by pressing the outer die 61 and the inner die 63 into the blank 9 supported by the punch 65. The inner diameter of the outer die 61 corresponds to the outer diameter of the metal workpiece 90, and the outer diameter of the inner die 63 corresponds to the inner diameter of the metal workpiece 90. The cutting edges on the inner peripheral surface of the outer die 61 and the outer peripheral surface of the inner die 63 have an R-shape with a radius of curvature. On the other hand, the edges of the inner and outer peripheral surfaces of the punch 65 do not have an R-shape.

[0095] When the blank 9 is finish-cut using such a cutting die, as shown in Fig. 19, a portion 9a that is on the outer side of an outer peripheral surface 91 of the metal processed product 90 is cut by the outer die 61, and a portion 9b that is on the inner side of an inner peripheral surface 92 of the metal processed product 90 is cut by the inner die 63. In this way, the metal processed product 90 (flat washer 900) as shown in Fig. 14 is formed.

[0096] Furthermore, the metal processed product 1 may be, for example, a disk-shaped plate 940 as shown in FIG.

[0097] Although the preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, the present invention is not limited to these examples. It is clear that a person skilled in the art to which the present invention pertains can conceive of various modifications and alterations within the scope of the technical ideas set forth in the claims, and it is understood that these also naturally fall within the technical scope of the present invention.

[0098] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0099] The inventors produced a number of processed product samples by varying the conditions for the semi-cutting and finish-cutting processes over a variety of ranges, as shown in Tables 1 and 2 below. A flat Zn-6%Al-3%Mg (by mass) alloy-plated steel sheet with a thickness of 3.2 mm was used as the first element body 2 (plated metal sheet). The coating weight of the steel sheet was 90 g / m 2 (One-sided).

[0100]

[0101]

[0102]

[0103] (Half-cutting step) The half-cutting step was carried out on the first element body 2 by the method shown in Fig. 7 or Fig. 10. The half-cutting process was carried out by forcing the first die 31 into the first element body 2 held by the first punch 41 and the first plate holder 51. The first die 31 was an annular body with a circular hole having an inner diameter of 85.00 mm. The first punch 41 was cylindrical so that it could be inserted into the circular hole of the first die 31. The outer diameter of the first punch 41 was set to 1 / 4 the clearance C shown in Table 1. 31-41 The cutting edges of the first die 31 and the first punch 41 have a radius of curvature R shown in Table 1. D1 , R P1 The pushing amount D of the first die 31 and the distance C between the first die 31 and the first punch 41 at the bottom dead center were P-D was as shown in Table 1.

[0104] (Finish Cutting Process) The first blank 2 after the half-cutting process was subjected to the finish cutting process using the method shown in FIG. 8 or FIG. 11 to obtain a processed product sample. Finish cutting was performed by forcing the second die 32 into the first blank 2 held by the second punch 42 and the second plate holder 52. The second die 32 was annular with a circular hole having the inner diameter shown in Table 2. The second punch 42 was cylindrical so that it could be inserted into the circular hole of the second die 32. The second die 32 used had an inner diameter that was basically changed depending on the clearance. However, in Comparative Example 2, a die having an inner diameter of 85.00 mm, the same as the first die 31, was used. The outer diameter of the second punch 42 was basically 85.00 mm. However, in Comparative Example 2, the outer diameter of the second punch 42 was 84.66 mm. The cutting edge of the second die 32 had a radius of curvature R shown in Table 2. D2 The cutting edge of the second punch 42 was an unrounded square shape.

[0105] The formulas (b3-1) to (b3-4) in the table relating to the finishing cutting process are as follows: 32-42 / t2) × 100 ≥ 7.0 × t2 3 -11.0 x t2 2 +4.9t2+1.7...(b3-1) (C 32-42 / t2) × 100 ≦ 7.8 × t2 2-0.6×t2+18.0...(b3-2) (C 32-42 / t2) × 100 ≦ 25.0 × t2 -1 ...(b3-3) (C 32-42 / t2) × 100 ≧ 2.3 (b3-4) where C 32-42 is the clearance (mm) between the second die 32 and the second punch 42, and t2 is the plate thickness of the half-cut portion 21 of the first body 2. In the columns in the table that indicate whether or not various conditions are met, "Yes" indicates that the condition is met, and "N" indicates that the condition is not met.

[0106] (Investigation of Processed Product Samples) The shape of the cut end 13 of each sample was examined, and evaluations of edge sagging, ductility burrs, the presence or absence of uncut defects, and step heights were performed. The number of days until red rust occurred during the atmospheric exposure test was also examined. The presence or absence of red rust was visually confirmed. The cut end surfaces of the processed product samples obtained through the above-described processes were examined for the ratio Z / t1 of the length Z of the sagging 13c in the thickness direction T to the thickness t1 of the cut end 13, the ratio Z / t1 of the length X of the sagging 13c in a plane direction perpendicular to the thickness direction T to the thickness t1 of the cut end 13, the length (mm) of the fracture surface 13e in the thickness direction T, the ratio L / t1 of the remaining length L of the plating component to the thickness t1 of the cut end 13, and the protrusion PA (mm) of the second shear surface 13d2 relative to the first shear surface 13d1. Furthermore, each processed sample was evaluated for edge sagging, ductility burrs, the presence or absence of uncut defects, and step differences, and the number of days until red rust occurred in an atmospheric exposure test was investigated. The results are shown in Table 3.

[0107] Regarding the evaluation of end sag, a circle (◯) indicates that the sag Z length to sheet thickness ratio (Z / t1) is less than 0.10. Regarding the evaluation of ductile burrs, a circle (◯) indicates that the length of the ductile burr 14 is less than 0.2 mm, and a cross (X) indicates that the length of the ductile burr 14 is 0.2 mm or more. Regarding the presence or absence of uncut defects, a circle (◯) indicates a state in which there are no uncut defects 15, and a cross (X) indicates a state in which a large burr has occurred due to an uncut defect 15. Regarding the evaluation of step height, a circle (◯) indicates that the protrusion amount PA (mm) of the second shear surface 13d2 relative to the first shear surface 13d1 is 0.25 mm or less, and a cross (X) indicates that the protrusion amount PA (mm) of the second shear surface 13d2 is more than 0.25 mm.

[0108] As shown in Tables 1 and 2, Examples 1 to 22 of the present invention are working examples that satisfy the following processing conditions: Regarding the semi-cutting step, the clearance C between the first die 31 and the first punch 41 is 31-41 (mm) is set as a negative clearance, and for the finish cutting process, the clearance C between the second die 32 and the second punch 42 is 32-42 (mm) is set as a positive clearance, and the clearance C between the first die 31 and the first punch 41 31-41 (mm) to the clearance C between the second die 32 and the second punch 42 32-42 The change to the thickness (mm) of the second die 32 is made by changing the side position from the first die 31 to the second die 32, and the change distance Md (mm) from the side position of the first die 31 to the side position of the second die 32 satisfies the following formula (b1): Md≦0.25 (b1) The clearance C between the second die 32 and the second punch 42 with respect to the remaining plate thickness t2 of the half-cut portion 21 32-42 The ratio (C 32-42 / t2) × 100(%) satisfies the following formula (b3-3): (C 32-42 / t2) × 100 ≦ 25.0 × t2 -1 ... (b3-3)

[0109] In contrast, in Comparative Example 1, the change distance Md (mm) from the side position of the first die 31 to the side position of the second die 32 is set to a relatively large value of 0.28, which does not satisfy the above formula (b1). Also, in Comparative Example 1, the clearance C between the second die 32 and the second punch 42 with respect to the remaining plate thickness t2 of the half-cut portion 21 is 32-42 The ratio (C 32-42 / t2) × 100(%) does not satisfy the above formula (b3-3).

[0110] In Examples 1 to 22 of the present invention, the protrusion amount PA (mm) of the second shear surface 13d2 relative to the first shear surface 13d1 was able to be kept to 0.25 mm or less, while in Comparative Example 1, the protrusion amount PA (mm) of the second shear surface 13d2 relative to the first shear surface 13d1 was relatively large at 0.28 mm. These results show that by satisfying the above formula (b1) and formula (b3-3), the step 13d3 of the cut edge 13 can be kept to 0.25 mm or less.

[0111] In Comparative Example 2, the clearance C between the first die 31 and the first punch 41 31-41 (mm) to the clearance C between the second die 32 and the second punch 42 32-42 The change to (mm) is made by changing the side position from the first punch 41 to the second punch 42, not by changing the side position from the first die 31 to the second die 32.

[0112] In Examples 1 to 22 of the present invention, the ratio of the remaining length of the coating component to the sheet thickness (L / t1) was 0.70 or more, but it was less than 0.70 in Comparative Example 2. These results confirmed that by changing the clearance by changing the side position from the first punch 41 to the second punch 42, it was possible to increase the remaining length L of the coating component at the cut end 13 after finish cutting.

[0113] Next, in the invention examples 1 and 2, the clearance C between the first die 31 and the first punch 41 in the half-cutting process is 31-41 This is an example where the thickness (mm) satisfies the following formula (a1) and is close to the upper or lower limit: -0.35 × t1≦C 31-41≦−0.0125×t1 (a1) Here, t1 is the plate thickness (mm) of the part to be half-cut of the first element body.

[0114] In contrast, in Reference Example 1, the clearance C 31-41 (mm) was set to a relatively small value, and this example does not satisfy the above formula (a1). In invention examples 1 and 2, half-cutting was performed as expected without complete cutting, but in reference example 1, complete cutting occurred in some areas. From these results, it was confirmed that by satisfying formula (a1), cracks were generated during half-cutting, which would cause complete cutting and result in large fracture surfaces, and it was possible to prevent the removed portion 20a from being completely cut off from the flange portion element 20 in the half-cutting step. Although not shown as a comparative example, the clearance C 31-41 When (mm) is less than −0.35×t1, the forming load required for half-cutting increases, the burden on the mold increases, and it is expected that the life of the mold will be shortened.

[0115] Next, in Examples 3, 4, 6, and 7 of the present invention, the curvature radius R of the cutting edge of the first die 31 was D1 (mm) satisfies the following formula (a2), and 0.10 × t1 ≦ R D1 ≦1.50 (a2) The radius of curvature R of the cutting edge of the first punch 41 P1 This is an example in which the distance (mm) satisfies the following formula (a3): 0.10 × t1≦R P1 ≦3.00 (a3) ​​Inventive Examples 3 and 4 are examples close to the upper or lower limit of formula (a2), and Inventive Examples 6 and 7 are examples close to the upper or lower limit of formula (a3).

[0116] In contrast, in Examples 14 and 15 of the present invention, the radius of curvature R of the cutting edge of the first die 31 D1 In addition, in Examples 16 and 22 of the present invention, the radius of curvature R of the cutting edge of the first punch 41 is P1are examples that do not satisfy the above formula (a3). As shown in Table 3, in Inventive Examples 3 and 4, the ratio L / t1 of the remaining length L of the coating component to the thickness t1 of the cut end 13 could be made 0.80 or more. Also, as shown in Table 3, by making the ratio L / t1 0.80 or more, good corrosion resistance can be obtained for 90 days or more until red rust appears on the cut end 13. On the other hand, D1, R P1 In Examples 14 and 16 of the present invention, in which the radius of curvature R was set relatively small, the ratio L / t1 was less than 0.80. D1 , R P1 In Examples 15 and 22 of the present invention, where the radius of curvature R was set relatively large, the ratio L / t1 was less than 0.80. The number of days until red rust appeared on the cut end 13 of Examples 14 to 16 and 22 of the present invention was about 60 days. This is practically usable, but is inferior to the corrosion resistance of Examples 3, 4, 6 and 7 of the present invention. From these results, it can be seen that the radius of curvature R D1 , R P1 It has been found that it is preferable that the above expressions (a2) and (a3) ​​are satisfied.

[0117] Next, in Examples 4 and 8 of the present invention, the remaining thickness t2 (mm) of the half-cut portion 21 in the half-cutting step satisfies the following formula (a4) and is close to the upper or lower limit of formula (a4): 0.20≦t2≦1.80 (a4)

[0118] In contrast, Inventive Example 17 is an example in which the remaining sheet thickness t2 exceeded 1.80 mm. Reference Example 2 is an example in which the remaining sheet thickness t2 was less than 0.20 mm. In Inventive Examples 4 and 8, the ratio L / t1 of the remaining coating component length L to the sheet thickness t1 of the cut end portion 13 was 0.80 or more, but in Inventive Example 17, the ratio L / t1 was less than 0.80. In Reference Example 2, partial cutting occurred after half-cutting. These results demonstrate that it is preferable for the remaining sheet thickness t2 (mm) to satisfy the above formula (a4).

[0119] Next, in Examples 5 and 13 of the present invention, in the finish cutting process, the cutting edge of the second die 32 has a radius of curvature R D2 (mm), and the radius of curvature R D2This is an example in which R (mm) satisfies the following formula (b2) and is close to the upper or lower limit of formula (b2): 0.20≦R D2 ≦1.20...(b2)

[0120] In contrast, in Example 18 of the present invention, the radius of curvature R D2 In Examples 5 and 13 of the present invention, the ratio L / t1 of the remaining length L of the coating component to the thickness t1 of the cut end 13 was 0.80 or more, but in Example 18 of the present invention, the ratio L / t1 was less than 0.80. D2 It was found that it is preferable that the thickness is 0.20 mm or more.

[0121] In addition, in Example 20 of the present invention, the radius of curvature R D2 In Examples 5 and 13 of the present invention, the generation of ductile burrs 14 was suppressed, but in Example 20 of the present invention, ductile burrs 14 were generated. From these results, it can be seen that the radius of curvature R D2 It was found that it is preferable that the thickness is 1.20 mm or less.

[0122] Next, in the first and fifth invention examples, the radius of curvature R of the second die 32 is D2 When the thickness t2 of the half-cut portion 21 is 1.00 mm or more, the clearance C between the second die 32 and the second punch 42 32-42 The ratio (C 32-42 / t2) × 100(%) satisfies the following formula (b3-1) and is close to the lower limit of formula (b3-1). 32-42 / t2) × 100 ≥ 7.0 × t2 3 -11.0 x t2 2 +4.9t2+1.7...(b3-1)

[0123] In contrast, in Examples 16, 17, and 20 of the present invention, the radius of curvature R D2 is 1.00 mm or more, and the ratio (C 32-42 / t2) × 100(%) is below the lower limit of the above formula (b3-1). In invention examples 1 and 5, the generation of ductile burrs 14 was suppressed, but in invention examples 16, 17, and 20, ductile burrs 14 were generated. From these results, it can be seen that the radius of curvature R D2 When the ratio (C32-42 / t2)×100(%) preferably satisfies the above formula (b3-1).

[0124] Next, in Example 6 of the present invention, the radius of curvature R of the second die 32 is D2 When the remaining thickness t2 of the half-cut portion 21 is less than 1.00 mm, the clearance C between the second die 32 and the second punch 42 32-42 The ratio (C 32-42 / t2) × 100(%) satisfies the following formula (b3-4) and is close to the lower limit of formula (b3-4). 32-42 / t2)×100≧2.3...(b3-4)

[0125] In contrast, in Example 15 of the present invention, the radius of curvature R D2 is less than 1.00 mm, and the ratio (C 32-42 / t2) × 100(%) is below the lower limit of the above formula (b3-4). In Example 6 of the present invention, the generation of ductile burrs 14 was suppressed, but in Example 15 of the present invention, ductile burrs 14 were generated. From these results, it can be seen that the radius of curvature R D2 When the ratio (C 32-42 / t2)×100(%) preferably satisfies the above formula (b3-4).

[0126] Next, in Examples 7 and 10 of the present invention, in the finish cutting process, the clearance C between the second die 32 and the second punch 42 with respect to the remaining plate thickness t2 of the half-cut portion 21 is 32-42 The ratio (C 32-42 / t2) × 100(%) satisfies the following formula (b3-2) and is close to the upper limit of formula (b3-2). 32-42 / t2) × 100 ≦ 7.8 × t2 2 -0.6×t2+18.0...(b3-2)

[0127] In contrast, in Examples 19 and 21 of the present invention, the ratio (C 32-42 / t2) × 100 (%) exceeds the upper limit of the above formula (b3-2). In Examples 7 and 10 of the present invention, the occurrence of uncut defects 15 was suppressed, but in Examples 19 and 21 of the present invention, uncut defects 15 occurred. From these results, it can be seen that the ratio (C 32-42 / t2)×100(%) preferably satisfies the above formula (b3-2).

[0128] Here, FIG. 21 shows the radius of curvature R D2 The clearance C between the second die 32 and the second punch 42 with respect to the remaining plate thickness t2 of the half-cut portion 21 when the thickness t2 is 1.00 mm or more 32-42 The ratio (C 32-42 22 is a graph showing the relationship between the radius of curvature R D2 The clearance C between the second die 32 and the second punch 42 with respect to the remaining plate thickness t2 of the half-cut portion 21 when the thickness t2 is less than 1.00 mm 32-42 The ratio (C 32-42 / t2) × 100 and the remaining plate thickness t2.

[0129] The vertical axis (Y axis) of the graphs shown in FIGS. 21 and 22 is the clearance C between the second die 32 and the second punch 42 relative to the remaining plate thickness t2 of the half-cut portion 21. 32-42 The ratio (C 32-42 / t2)×100(%). The vertical axis (Y axis) represents the remaining plate thickness t2 of the half-cut portion 21.

[0130] In the graph, circular or triangular plots numbered "a1" or the like indicate each example. "a" indicates a plot of an example of the present invention, and "b" indicates a plot of a comparative example. The plot numbers correspond to the numbers of each example. The circular plots indicate examples in which the occurrence of ductile burrs 14 and uncut defects 15 during finish cutting was suppressed and the protrusion amount PA (mm) of the second shear surface 13d2 relative to the first shear surface 13d1 was suppressed to 0.25 mm or less. The triangular plots indicate examples in which ductile burrs 14 or uncut defects 15 occurred or the protrusion amount PA (mm) of the second shear surface 13d2 exceeded.

[0131] From the graphs of FIGS. 21 and 22, it can be seen that the occurrence of the ductile burrs 14 and the uncut defects 15 and the protrusion amount PA of the second shear surface 13d2 are proportional to the ratio (C 32-42 / t2)×100(%) and the remaining plate thickness t2 of the half-cut portion 21.

[0132] The curve shown by the solid line in the graph is an approximation curve obtained from a test example in which the step 13d3 of the cut end 13 was suppressed while lengthening the remaining length L of the plating component, and corresponds to the above-mentioned formula (b3-3). Formula (b3-3) is shown below. The regression curve or straight line in the figure is the ratio (C 32-42 / t2) × 100 is represented as Y, and the remaining plate thickness t2 is represented as X. (C 32-42 / t2) × 100 ≦ 25.0 × t2 -1 ... (b3-3)

[0133] Ratio (C 32-42 / t2)×100(%) and the remaining plate thickness t2 of the semi-cut portion 21 are included in the region below this approximate curve, it can be seen that the step 13d3 of the cut end portion 13 can be suppressed while the remaining length L of the plating component is lengthened.

[0134] The curve shown by the dashed line in the graph is an approximation curve obtained from a test example in which the occurrence of the uncut defect 15 was suppressed, and corresponds to the above-mentioned formula (b3-2). Formula (b3-2) is shown below again. (C 32-42 / t2) × 100 ≦ 7.8 × t2 2 -0.6×t2+18.0...(b3-2)

[0135] Ratio (C 32-42 / t2)×100(%) and the remaining plate thickness t2 of the partially cut portion 21 are included in the region below this approximate curve, it can be seen that the occurrence of uncut defects 15 can be suppressed.

[0136] The curve shown by the dashed line in the graph of FIG. 21 is the radius of curvature R D2 This is an approximate curve obtained from a test example in which the generation of ductile burrs 14 was suppressed when the thickness was 1.00 mm or more, and corresponds to the above-mentioned formula (b3-1). Formula (b3-1) is shown below. 32-42 / t2) × 100 ≥ 7.0 × t2 3 -11.0 x t2 2 +4.9t2+1.7...(b3-1)

[0137] radius of curvature R D2 When the ratio (C 32-42 / t2)×100(%) and the remaining thickness t2 of the half-cut portion 21 are included in the region above this approximate curve, it can be seen that the generation of ductile burrs 14 can be suppressed.

[0138] In the graph of FIG. 22, the straight line indicated by the two-dot chain line represents the radius of curvature R D2 This is an approximate straight line obtained from a test example in which the generation of ductile burrs 14 could be suppressed when the thickness was less than 1.00 mm, and corresponds to the above-mentioned formula (b3-4). Formula (b3-4) is shown below. 32-42 / t2)×100≧2.3...(b3-4)

[0139] radius of curvature R D2 When the ratio (C 32-42 / t2)×100(%) and the remaining thickness t2 of the half-cut portion 21 are included in the region above this approximate curve, it can be seen that the generation of ductile burrs 14 can be suppressed.

[0140] REFERENCE SIGNS 1: Metal processed product 2: First element body 13: Cut end 13c: Sagging 13d: Shear surface 13d1: First shear surface 13d2: Second shear surface 13e: Fracture surface 13f: Burr 13g: Plating layer 21: Partially cut portion 31: First die 32: Second die 41: First punch 42: Second punch

Claims

1. A method for manufacturing a metal processed product using a plated metal sheet having a plating layer on a surface thereof as a starting material, for manufacturing a metal processed product having a cut end along a thickness direction of the starting material, comprising: a half-cutting step of cutting a first body formed from the starting material in half in the thickness direction using a first die and a first punch to form a half-cut portion; and a finish-cutting step of cutting the half-cut portion in the same direction as the half-cutting using a second die and a second punch to obtain the metal processed product having the cut end, wherein with respect to the half-cutting step: - a clearance C between the first die and the first punch is 31-41 (mm) is set to a negative clearance, and in the finish cutting process, the clearance C between the second die and the second punch is 32-42 (mm) is set to a positive clearance, and the clearance C between the first die and the first punch 31-41 (mm) to the clearance C between the second die and the second punch 32-42 a change in the thickness of the first die to a thickness of the second die by changing a side position from the first die to the second die, and a change distance Md (mm) from the side position of the first die to the side position of the second die satisfies the following formula (b1): Md≦0.25 ... (b1) A clearance C between the second die and the second punch with respect to a remaining plate thickness t2 of the half-cut portion, which corresponds to a distance in a pressing direction of the first die between a connecting position of the cutting edge and the side of the first die and an upper surface of the first punch in contact with the lower surface of the first blank when the first die is pressed in to the bottom dead center 32-42 The ratio of (C 32-42 / t2) × 100(%) satisfies the following formula (b3-3): 32-42 / t2) × 100 ≦ 25.0 × t2 -1 ...(b3-3) A manufacturing method for a metal processed product.

2. Regarding the semi-cutting step, the clearance C between the first die and the first punch 31-41 (mm) satisfies the following formula (a1), -0.35 × t1 ≦ C 31-41 ≦−0.0125×t1 (a1) Here, t1 is the plate thickness (mm) of the portion to be cut in half of the first body, and the cutting edge of the first die has a radius of curvature R D1 (mm), and the radius of curvature R D1 satisfies the following formula (a2), D1 ≦1.50 (a2) The cutting edge of the first punch has a radius of curvature R P1 (mm), and the radius of curvature R P1 (mm) satisfies the following formula (a3): 0.10 × t1≦R P1 ≦3.00...(a3) The remaining thickness t2 (mm) of the half-cut portion, which corresponds to the distance along the pressing direction of the first die between the connection position of the cutting edge and side of the first die and the upper surface of the first punch in contact with the lower surface of the first blank when the first die is pressed down to the bottom dead center, satisfies the following formula (a4): 0.20≦t2≦1.80...(a4). A method for manufacturing a metal processed product as described in claim 1.

3. Regarding the finish cutting process, the cutting edge of the second die has a radius of curvature R D2 (mm), and the radius of curvature R D2 (mm) satisfies the following formula (b2), 0.20≦R D2 ≦1.20 ... (b2) - The above ratio (C 32-42 / t2) × 100 (%) is the radius of curvature R D2 When is 1.00 mm or more, the following formulas (b3-1) and (b3-2) are satisfied, and (C 32-42 / t2) x 100 ≧ 7.0 x t2 3 -11.0 x t2 2 +4.9t2+1.7...(b3-1) (C 32-42 / t2) x 100 ≤ 7.8 x t2 2 −0.6×t2+18.0 (b3-2) the radius of curvature R D2 is less than 1.00 mm, the following formulas (b3-4) and (b3-2) are satisfied. 32-42 / t2)×100≧2.3 ...(b3-4) (C 32-42 / t2) x 100 ≤ 7.8 x t2 2 -0.6 × t2 + 18.0 ... (b3-2) A method for manufacturing a metal processed product according to claim 1 or 2.

4. A metal processed product whose base material is a plated metal plate having a plating layer on its surface, and has a cut end portion along the plate thickness direction of the base material, wherein the cut end portion has a sag, a sheared surface, and a fracture surface, or a sag and a sheared surface, in the plate thickness direction, the sheared surface has a first sheared surface continuing from the sag and a second sheared surface continuing from the first sheared surface, in the plate thickness direction, the second sheared surface is formed so as to protrude from the first sheared surface in a direction perpendicular to the plate thickness direction, and the amount of protrusion of the second sheared surface in the direction perpendicular to the first sheared surface is more than 0 mm and not more than 0.25 mm, a ratio L / t1 of a remaining plating component length L where the sheared surface is covered by the plating layer on the surface to a plate thickness t1 of the cut end portion is 0.80 or more, and a ratio Z / t1 of a length Z of the sag in the plate thickness direction to a plate thickness t1 of the cut end portion is more than 0 and less than 0.10.

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