Method for producing processed metal product, and processed metal product

Abstract

The invention provides a method for manufacturing a metal processed product, which can reduce the height of a protruding part derived from a protruding corner part remaining after a coining process. This method for manufacturing a processed metal product comprises: a half-cutting step in which a gap C31-41 (mm) between a first die and a first punch is set to be a negative gap, a blade tip of the first die and a blade tip of the first punch are set to be R-shapes having prescribed radii of curvature RD1 and RP1 (mm), and a fine-cutting step in which the radius of curvature RD1 and RP1 (mm) is set to be a negative gap, and a fine-pressing step in which the radius of curvature RD1 and RP1 (mm) is set to be a negative gap; in the press-fitting step, a protruding corner portion having a height h (mm) corresponding to a separation distance along a press-fitting direction of a first die between a position on a blade edge of a first punch on an extension line of a side surface of the first die and an extension line of an upper surface of the first punch in contact with a lower surface of a first green body is formed on the half-cut portion. The pad has a vertical wall surface, a bottom wall surface, and a pressing surface, and when an area of a region surrounded by an extended surface of the vertical wall surface, an extended surface of the bottom wall surface, and the pressing surface is defined as a coining area Ar, the coining area Ar is set to satisfy the following formula: h < =-1.09 Ar + 1.04.

Description

TECHNICAL FIELD

[0001] The present application relates to a manufacturing method of a metal processed product having a plated metal sheet having a plated layer on a surface as a blank, a cut end portion along a sheet thickness direction of the blank, and a coining surface formed at a corner portion of the cut end portion, and the metal processed product. BACKGROUND

[0002] In recent years, as parts of devices such as automobiles and home electric appliances, metal processed products having a plated metal sheet having a plated layer on a surface as a blank are increasingly used. By using a plated metal sheet as a blank, plating treatment after forming of the metal processed product can be omitted, and manufacturing cost can be suppressed. In addition, by omitting the plating treatment after forming, deterioration of dimensional accuracy of the parts caused by the plating treatment after forming can be avoided. The approach of omitting the plating treatment after forming is particularly studied in parts such as motor housings that require high dimensional accuracy.

[0003] In a case where the plating treatment after forming is omitted, a region where the metal sheet blank is exposed appears at the cut end portion of the metal processed product. Depending on the environment in which the processed product is placed, red rust sometimes occurs in the region where the metal sheet blank is exposed. The red rust deteriorates the appearance of the processed product.

[0004] In Patent Literature 1 described below, a rust-preventing blanking method of a cut end portion is proposed in which, in a first step, a punch and a die having an R shape imparted to a tool tip are used to perform semi-cutting (semi-blanking) with a negative clearance, and in a second step, only the die (or the punch) is imparted with an R to perform fine cutting with a positive clearance, thereby causing the plated layer of the surface to wrap around the end surface of the cut end portion. In addition, in this Patent Literature 1, it is also disclosed that coining processing is performed after the fine cutting step. In the coining processing, a smoothing surface is formed at a corner portion (corner portion) of the cut end portion of the processed product on the fracture surface side after the fine cutting. The smoothing surface is less likely to generate red rust than the fresh fracture surface which is in a rough surface shape. In addition, by the coining processing, burrs generated at the time of fine cutting can be flattened. The coining processing is performed by clamping the cut end portion with a pad having a pressing surface and a coining block, and compressing the corner portion on the fracture surface side with the pressing surface.

[0005] PRIOR ART DOCUMENTS

[0006] PATENT LITERATURE

[0007] Patent Literature 1: International Publication No. 2022 / 039168 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] The present inventors have studied a method of winding more plating around the end surface of the cut end portion in order to increase the rust-preventing effect. In order to increase the winding amount of the plating, the radius of curvature of the tip of the punch and the die for the half-cut is further increased, and the press-in amount of the die is further increased, resulting in the following new problems: a protrusion called a horn portion is generated at the lower portion of the cut end portion in the finish-cutting process, and a large protrusion derived from the horn portion is formed on the lower surface of the cut end portion after the finish-pressing process. The protrusion is formed by flattening the horn portion by finish-pressing. These problems are not considered in the above-described Patent Document 1.

[0010] For example, in a drawn product such as a motor case, a flange for fixing the product to other equipment is sometimes provided. The end portion of the flange is formed by cutting. If a large protrusion is formed on the lower surface of the flange portion, a space is generated between the flange and the other equipment when the flange is fixed to the other equipment, which becomes a cause of shaking, and can lead to deterioration of the performance of the product.

[0011] The present application is made to solve the above-described problems, and one of the objects thereof is to provide a manufacturing method of a metal product capable of reducing the height of a protrusion derived from a horn portion remaining after a finish-pressing process. Another object of the present application is to provide a metal product capable of reducing shaking caused by a protrusion.

[0012] Solution to the problem

[0013] The manufacturing method of the metal product of the present application, in one embodiment, is a manufacturing method of a metal product that uses a plated metal sheet having a plating layer on a surface as a blank, has a cut end portion in a sheet thickness direction of the blank, and has a finish-pressing surface formed at a corner portion of the cut end portion, the manufacturing method including: a half-cutting process of forming a half-cut portion by half-cutting a first blank formed of the blank in the sheet thickness direction using a first die and a first punch; a finish-cutting process of obtaining a second blank having the cut end portion by finish-cutting the half-cut portion from the same direction as the half-cutting using a second die and a second punch; and a finish-pressing process of obtaining the metal product having the finish-pressing surface formed at the corner portion of the cut end portion by pressing the corner portion of the cut end portion of the second blank to a pad, and

[0014] In the half-cutting process,

[0015] The clearance C between the first die and the first punch 31-41 (mm) is set to a negative clearance,

[0016] The tips of the first die and the first punch are set to have an R shape having a prescribed radius of curvature R D1 , R P1 (mm),

[0017] A burr portion having a height h (mm) is formed at the half-cut portion, the height h (mm) corresponds to a separation distance along the press-in direction of the first punch of a position on the tip of the first punch on the extension line of the side surface of the first die and an extension line of the upper surface of the first punch in contact with the lower surface of the first blank, and is represented by the following equation:

[0018] [Equation 1]

[0019]

[0020] Regarding the coining process,

[0021] The pad has a longitudinal wall surface, a bottom wall surface, and a planar or curved pressing surface that connects the longitudinal wall surface and the bottom wall surface at an angle at which the longitudinal wall surface and the bottom wall surface abut and that presses the corner portion of the cut end portion,

[0022] When the pad is observed in a cross section along the pressing direction of the corner portion, the area of a region surrounded by the extension surface of the longitudinal wall surface, the extension surface of the bottom wall surface, and the pressing surface is set as a coining area Ar (mm 2 ), the coining area Ar (mm 2 ) is set to satisfy the following equation:

[0023] h ≤ -1.09 Ar + 1.04.

[0024] The metal processed product of the present application is, in one embodiment, a metal processed product having a cut end portion along the plate thickness direction of the material, using a plated metal sheet having a plated layer on the surface as a blank, the cut end portion has, in order from the upper surface side toward the lower surface side along the plate thickness direction of the cut end portion, a burr, a shear surface, and a coining surface, the shear surface has, in the plate thickness direction, a first shear surface continuous with the burr and a second shear surface continuous with the first shear surface, the inclination angle θd1 of the first shear surface with respect to the plate thickness direction and the inclination angle θd2 of the second shear surface with respect to the plate thickness direction satisfy θd1 > θd2, the ratio L1 / t1 of the plated component remaining length L1 (mm) of the shear surface covered with the plated layer to the plate thickness t1 (mm) of the cut end portion is 0.80 or more, the ratio Z / t1 of the length Z (mm) of the burr in the plate thickness direction toward the lower surface of the cut end portion with the upper surface of the cut end portion as a reference to the plate thickness t1 (mm) of the cut end portion is -0.10 or more and less than 0.10, a protrusion having a height h0 of more than 0 mm and 0.20 mm or less is provided at the lower portion of the coining surface, the plated layer of the surface is wrapped around from the lower surface of the cut end portion to the end surface of the cut end portion, and the height Lc (mm) in the plate thickness direction from the lower surface of the upper end of the plated layer wrapped around from the lower surface is 0.10 times or more of the curvature radius R0 (mm) or the taper height C0 (mm) of the coining surface.

[0025] Effects of the invention

[0026] According to one embodiment of the method for manufacturing metal articles of the present invention, the height of the protrusions originating from the corner portions remaining after the precision pressing process can be reduced. Furthermore, according to another embodiment of the metal article of the present invention, the wobbling caused by the protrusions can be reduced. Attached Figure Description

[0027] Figure 1 This is a perspective view showing an example of a metal article manufactured by the manufacturing method of the metal article according to an embodiment of the present invention.

[0028] Figure 2 It means Figure 1 An illustration of the first pattern of the cut end in region A.

[0029] Figure 3 It means Figure 1 An illustration of the second pattern of the cut-off end in region A.

[0030] Figure 4 It means Figure 1 An illustration of the third pattern of the cut-off end in region A.

[0031] Figure 5 It means Figure 1 An illustration of the fourth pattern of the cut-off end in region A.

[0032] Figure 6 yes Figure 2 Detailed view of the cross-section of the cut end.

[0033] Figure 7 It is a detailed representation Figure 6 The graph of region B.

[0034] Figure 8 This is a diagram illustrating an example of the relationship between collapsed edge Z and collapsed edge X.

[0035] Figure 9 This is an explanatory diagram illustrating a method for manufacturing a metal workpiece according to an embodiment of the present invention.

[0036] Figure 10 It means in Figure 9 An explanatory diagram of the first die and the first punch used in the semi-cutting process.

[0037] Figure 11 It is an enlarged representation Figure 10 Explanatory diagram of the half-cut section.

[0038] Figure 12 It indicates accompaniment Figure 10 A diagram illustrating the changes in the radius of curvature of the tip of the first punch and the changes in the clearance at the protruding corner.

[0039] Figure 13 is a drawing showing a second punch and a second die used in a finish cutting process of Figure 9

[0040] Figure 14 is a drawing showing a pad and a finish block used in a finish pressing process of Figure 9

[0041] Figure 15 is a photograph showing a cut end portion of a metal processed product after the finish pressing process.

[0042] Figure 16 is a perspective view showing an example of the processed product.

[0043] Figure 17 is a perspective view showing another example of the processed product.

[0044] Figure 18 is a perspective view showing another example of the processed product.

[0045] Figure 19 is a perspective view showing another example of the processed product.

[0046] Figure 20 is a schematic view showing an example of a cutting die for manufacturing the processed product of Figure 16

[0047] Figure 21 is a schematic view showing a state in which a blank is subjected to blanking processing by the cutting die of Figure 20

[0048] is a schematic view showing an example of a finish pressing die for manufacturing the processed product of Figure 22 Figure 16

[0049] Figure 23 is a perspective view showing another example of the processed product.

[0050] Figure 24 is a graph showing a relationship between a height of a burr portion after half cutting (before finish cutting) in the example and a finish pressing area of a pad used in the finish pressing process. DETAILED DESCRIPTION

[0051] ​​​​​The following describes modes for carrying out the present application with reference to the drawings. The present application is not limited to the embodiments, and the constituent elements can be modified and embodied within the scope of the gist thereof. In addition, various technical solutions can be formed by appropriate combinations of the plurality of constituent elements disclosed by the embodiments. For example, several constituent elements can be deleted from all the constituent elements shown in the embodiments. Furthermore, the constituent elements of different embodiments can be appropriately combined.

[0052] <About the Metal Processed Product>

[0053] Figure 1 is a perspective view showing an example of the metal processed product 1 manufactured by the manufacturing method of the metal processed product 1 of the embodiment of the present application. Figure 1 The metal processed product 1 shown is a motor case using a plated metal sheet having a plated layer on a surface as a blank. Figure 1 The motor case shown can be formed by performing a forming process such as drawing processing on a flat plate-shaped plated metal sheet.

[0054] As shown in Figure 1 The metal processed product 1 of the embodiment has a main body portion 10, a protrusion portion 11, and a flange portion 12.

[0055] The main body portion 10 has a hollow cylindrical side wall 101 and a top wall 103 formed so as to cover one end of the side wall 101. The top wall 103 is sometimes also called a bottom wall or the like depending on the orientation in which the metal processed product 1 is used. Figure 1 The cross-sectional shape based on the XY plane of the main body portion 10 of the metal processed product 1 shown (the cross-sectional shape of the main body portion 10) is a perfect circle, but the present application is not limited to this example. The cross-sectional shape based on the XY plane of the main body portion 10 can also be another shape such as an ellipse, a polygon, or the like, for example.

[0056] The protrusion portion 11 is a protruding body protruding from the top wall 103 to the outside of the central axis direction (Z direction) of the main body portion 10. In addition, the protrusion portion 11 is not necessarily formed, and the top wall 103 can also be flat.

[0057] The flange portion 12 is a plate portion extending from the end portion of the main body portion 10 (i.e., the other end of the side wall 101) to the outside of the radial direction (X, Y direction) of the main body portion 10. The shape of the flange portion 12 is arbitrary. The flange portion 12 of the embodiment extends in the radial direction of the main body portion 10 in the entire region in the circumferential direction of the main body portion 10. In the flange portion 12, a plurality of screw holes 121 are provided separately from each other in the circumferential direction of the main body portion 10. Screws 123 are inserted into the screw holes 121. The metal processed product 1 can be fixed to a mounting object such as a vehicle body or the like by being fastened to the mounting object using the screws 123.

[0058] The flange portion 12 of the present embodiment is formed by cutting the flange portion blank 20 (the first flange portion blank) having an outer diameter larger than the outer diameter of the flange portion 12 finally formed in the metal processed product 1. Figure 9 That is, the metal processed product 1 of the present embodiment has the cut end portion 13 on the outer periphery of the flange portion 12. The cut end portion 13 is along the plate thickness direction of the plated metal sheet as a blank.

[0059] The cutting includes cutting, blanking, and piercing, and the like. The cutting is a process of cutting a cutting target along a prescribed straight line or curve. The blanking is a process of blanking a product from a cutting target. The piercing is a process of blanking a portion that is not a product from a cutting target to obtain a product having an opening. Figure 1 The flange portion 12 shown can be obtained by blanking from a flange portion blank.

[0060] The base material of the plated metal sheet can be, for example, any metal such as steel, copper, copper alloy, aluminum, or aluminum alloy. Typically, the plated metal sheet is a plated steel sheet. The manufacturing method of the metal processed product 1 of the embodiment of the present application described later is particularly suitable for the case where the base material is steel. This is because steel is susceptible to rusting, and the advantage of imparting corrosion resistance is greater.

[0061] 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 layer has a sacrificial corrosion protection effect on the steel sheet as the base material. Therefore, it is possible to suppress corrosion of the base material exposed portion from the end surface of the cut end portion 13, and it is possible to further improve the corrosion resistance of the manufactured metal member. As the Zn-based plating, hot-dip galvanizing, alloyed hot-dip galvanizing, Zn-Ni-based plating, Zn-Al-based plating, Zn-Mg-based plating, Zn-Al-Mg-based plating, and the like can be given.

[0062] The plate thickness of the plated metal sheet (the plate thickness of the base material metal sheet + the thickness of the plating layer) is not particularly limited. The plate thickness of the plated metal sheet can 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, and the like.

[0063] When the plating adhesion amount of the plated metal sheet is a certain amount or more, the plated metal is likely to be wound into the end surface of the cut end portion 13. By winding the plated metal, it is possible to improve the corrosion resistance of the end surface of the cut end portion 13. The preferable lower limit of the plating adhesion amount is 30 g / m 2 . The more preferable lower limit of the plating adhesion amount is 45 g / m 2 . The preferable upper limit of the plating adhesion amount is 450 g / m 2 . The more preferable upper limit of the plating adhesion amount is 190 g / m 2 .

[0064] <About the cut end portion of the processed product>

[0065] Next, using Figures 2-8 The cut end portion 13 of the metal work 1 will be described. Figures 2-5 is a view showing Figure 1 the first to fourth states of the cut end portion 13 in the area A. Figures 2-5 The left side portion of Figure 1 is a sectional view of the cut end portion 13 on the ZX plane of Figures 2-5 The right side portion of Figure 1 is a front view of the cut end portion 13 when viewed in the X direction of Figure 6 is a detailed view of the cross section of the cut end portion 13 of Figure 2 is a view showing the area B in detail. Figure 7 is a graph showing an example of the relationship between the collapse Z and the collapse X. In Figure 6 , the plate thickness direction T of the cut end portion 13 is the same direction as the central axis direction (Z direction) of the metal work 1 shown in Figure 8 . In Figures 2-6 , the plating layers 13f, 13k shown in Figure 1 are omitted. Figures 2-5 Figure 6 As particularly shown in

[0066] The cut end portion 13 has, in the plate thickness direction T of the cut end portion 13, in order from the upper surface 13a side toward the lower surface 13b side, a collapse 13c, a sheared surface 13d, and a coining surface 13e. Figure 2

[0067] The upper surface 13a is a surface (a pressed-in surface) on the side into which the tip of the cutting die (the first punch 31 and the second punch 32 of Figure 10 and Figure 13 ) is pressed in at the time of cutting processing of the flange portion blank. The lower surface 13b is a surface on the side from which the tip of the cutting die is pulled out at the time of cutting processing of the flange portion blank.

[0068] The collapse 13c is a portion in which the surface of the flange portion blank (a plated metal sheet as a blank) is deformed by a stretching force acting on the surface of the flange portion blank when the tip of the cutting die is pressed into the flange portion blank. The collapse 13c typically appears as a smooth surface having a curvature in the cut end portion 13. In the present specification, the dimension of the collapse 13c in the plate thickness direction T of the cut end portion 13 is referred to as "collapse Z", and the dimension of the collapse 13c in a planar direction orthogonal to the plate thickness direction T is referred to as "collapse X".

[0069] ​​The shear surface 13d is the surface formed by the cutting edge of the flange blank being sheared by the tip of the cutting die. The shear surface 13d is adjacent to the burr edge 13c in the thickness direction T of the cut end 13. The shear surface 13d typically appears as a smooth surface at the cut end 13. It is formed by the application of compressive (pressure) force after the cutting die contacts the workpiece, causing it to bite into the workpiece. This friction with the side of the cutting die results in the shear surface 13d, which sometimes exhibits a metallic luster. Fine, striped sliding damage is sometimes observed on the shear surface 13d in the thickness direction T.

[0070] The corner portion 13m on the lower surface 13b side of the end 13 is cut off by the precision pressing process described later (see reference). Figure 9 The surface is formed by pressing or compressing. In this embodiment, the pressed surface 13e is a conical surface (a flat, chamfered surface). The angle θ of the extension direction of the pressed surface 13e relative to the extension direction of the lower surface 13b can be, for example, 45° or 60°. However, as... Figure 5 As shown, the precision-pressed surface 13e can also be other pressing or compressing surfaces such as an R-surface (a curved, chamfered surface). The precision-pressed surface 13e typically appears as a smooth surface at the cut end 13, where the unevenness of the fracture surface is flattened. The cut end 13 may also be burr-free. This is because even if burrs are generated during the cutting process, they will be flattened by the precision pressing process.

[0071] In the cut-off end 13, as a method for determining the collapsed edge 13c, the shear surface 13d, and the fine pressing surface 13e (a method for measuring their respective lengths), there are methods such as observing and measuring the shape profile of the cut-off end 13 from the appearance based on the above characteristics using a microscope or a profile measuring instrument.

[0072] In this embodiment, the shear surface 13d has a first shear surface 13d1 continuous with the collapsed edge 13c and a second shear surface 13d2 continuous with the first shear surface 13d1 in the thickness direction T. The lower end of the second shear surface 13d2 may be continuous with the fine pressing surface 13e. These first shear surfaces 13d1 and second shear surfaces 13d2 are surfaces with different inclination angles θd1 and θd2 relative to the thickness direction T. The inclination angles θd1 and θd2 of the first shear surface 13d1 and the second shear surface 13d2 relative to the thickness direction T satisfy θd1 > θd2. In other words, the first shear surface 13d1 is more inclined relative to the thickness direction T than the second shear surface 13d2. Figure 2 As shown in the right-hand portion, when viewed from the front of the cut end 13, a boundary line can sometimes be seen between the first shear surface 13d1 and the second shear surface 13d2. In a direction orthogonal to the plate thickness direction T (the X-axis direction in the figure), the second shear surface 13d2 may protrude outwards from the first shear surface 13d1.

[0073] In the metal processed product 1 of the present embodiment, as shown in Figure 6 In particular, the plating layer 13f is wound around from the upper surface 13a of the cut end portion 13 to the sheared surface 13d. When the tip of the cutting die gradually bites into the flange portion blank, the plating layer 13f is stretched by the cutting die and wound around the sheared surface 13d. By this winding of the plating layer 13f, at least a portion of the sheared surface 13d is covered with the plating layer 13f, and red rust can be suppressed from occurring in the portion covered with the plating layer 13f. In addition, when the plating layer 13f is a Zn-based plating layer, by the sacrificial corrosion protection effect of the Zn-based plating layer, red rust can also be suppressed from occurring in the vicinity of the portion covered with the plating layer 13f.

[0074] In the metal processed product 1 of the present embodiment, the length LI of the plating layer 13f covering at least a portion of the sheared surface 13d and the collapse 13c from the upper surface 13a of the cut end portion 13 is 0.80 times or more of the plate thickness tl of the cut end portion 13 of the metal processed product 1. That is, the ratio LI / tl of the plating layer 13f covering component remaining length LI at which the sheared surface 13d is covered with the plating layer 13f on the surface of the plated metal sheet to the plate thickness tl of the cut end portion 13 is 0.80 or more. The length LI of the plating layer 13f or the plating layer 13f covering component remaining length LI can also be said to be the distance between the upper surface 13a of the cut end portion 13 and the lower end of the plating layer 13f in the plate thickness direction T of the cut end portion 13. The plate thickness tl of the cut end portion 13 can also be said to be the distance between the upper surface 13a and the lower surface 13b of the cut end portion 13 in the plate thickness direction T of the cut end portion 13. More specifically, the plate thickness tl of the cut end portion 13 can be the distance between the upper surface 13a and the lower surface 13b at a position (a position sufficiently far from the outer edge of the cut end portion 13) that is not affected by the collapse 13c and the coining surface 13e. The plate thickness tl of the cut end portion 13 and the plate thickness of the flange portion 12 shown in Figure 1 are equal.

[0075] Here, in the coining process when the coining surface 13e is formed, a pressing or compressive force is applied to the cut end portion 13 from the lower surface 13b side toward the upper surface 13a side of the cut end portion 13, and at times the collapse 13c, the sheared surface 13d, and the fracture surface are pushed up inside the cut end portion 13. Depending on the amount of processing of the coining process, the collapse 13c of the cut end portion 13 at times does not reach the upper surface 13a, but is Figure 2 rather assumes Figure 3 or Figure 4 the aspect shown.

[0076] Figure 3 represents an aspect in which the intersection position 13g of the collapse 13c and the sheared surface 13d is pushed up to the same height position as the upper surface 13a by the coining process. Figure 4 represents an aspect in which the intersection position 13g of the collapse 13c and the sheared surface 13d is pushed up to a position higher than the upper surface 13a by the coining process. In Figure 3and Figure 4 In any state of the cut end portion 13, a deformed surface corresponding to the burr 13c remains continuously with the smooth upper surface 13a of the cut end portion 13. The deformed surface is sometimes bulged upward more than the smooth upper surface 13a. In the present specification, such a deformed surface is also treated as the burr 13c. In particular, the burr 13c that is bulged upward is sometimes also called the burr 13c that is bulged upward. Figure 4 The burr 13c that is bulged upward is sometimes also called the burr 13c that is bulged upward.

[0077] As shown in FIG. 1, in the case of the burr 13c that is bulged upward, that is, in the case where the interface position 13g of the burr 13c and the sheared surface 13d is pushed up to a position higher than the upper surface 13a, if the amount of the push-up of the interface position 13g is too large, an adverse situation such as impairment of the stability of the screw 123 (refer to FIG. 2) due to excessive deformation of the cut end portion 13, and the like can sometimes occur. Figure 4 Figure 1

[0078] In the metal processed product 1 of the present embodiment, the ratio Z / t1 of the length Z of the burr 13c in the sheet thickness direction T toward the lower surface 13b of the cut end portion 13 from the upper surface 13a of the cut end portion 13 to the sheet thickness t1 of the cut end portion 13 is -0.10 or more and less than 0.10. By the ratio Z / t1 being -0.10 or more, it is possible to avoid the burr 13c that is bulged upward from excessively protruding from the upper surface 13a, and it is possible to suppress the possibility of occurrence of an adverse situation due to excessive deformation of the cut end portion 13. By the ratio Z / t1 being less than 0.10, it is possible to avoid the burr X (the size of the burr 13c in the planar direction orthogonal to the sheet thickness direction T) from becoming too large. It is more preferable that the ratio Z / t1 be 0 or more and less than 0.10. Thereby, it is possible to make the shape of the cut end portion 13 a more preferable state. The ratio Z / t1 can be -0.10 or more and less than 0.

[0079] Further, it is known that the burr Z and the burr X have a correlation relationship with each other. In the present embodiment, the burr Z and the burr X are correlated with each other. Figure 8 An example of the relationship of the burr Z and the burr X of the cut end portion 13 when the blanking processing is performed by one process is shown. Figure 8 An example of the relationship of the burr Z and the burr X of the cut end portion 13 of the product when the blanking processing is performed by setting the curvature radius of the cutting edge of the blanking die to the sheet thickness of the flange portion blank 0.01 to 0.30 times and the clearance of the blanking die to 0.01 to 0.20 times the sheet thickness is shown. Figure 8 As shown in FIG. 3, when the blanking processing is performed by one process, the burr X that appears in the planar direction with respect to the burr Z in the sheet thickness direction becomes about 3 to 4 times larger. This correlation relationship is a relationship before the press processing, but an influence is also exerted after the press processing.

[0080] ​​In measuring the collapse Z, the height position of the upper surface 13a of the cut end portion 13 is taken as a reference position (0 point), and the length to a position lower than the upper surface 13a is defined as a positive length, and the length to a position higher than the upper surface 13a is defined as a negative length. The reference position is set to the height position of the upper surface 13a of the cut end portion 13 at a position (a position sufficiently far from the outer edge of the cut end portion 13) not affected by the collapse 13c and the coining surface 13e.

[0081] For example, the measurement points of the height position can be scanned on the surface of the cut end portion 13 from a position not affected by the collapse 13c and the coining surface 13e toward the outer edge of the cut end portion 13. As shown in a first mode of Figure 2 When the boundary position 13g is at a position lower than the upper surface 13a, as shown in a second mode of Figure 3 When the boundary position 13g is at a position higher than the upper surface 13a, as shown in a third mode of Figure 4 When the boundary position 13g is at a position higher than the upper surface 13a, as shown in a third mode of The length Z of the collapse 13c can be set to the length in the plate thickness direction T between the height position of the surface of the cut end portion 13 immediately before the height position takes a discontinuous value and the reference position. The height position of the surface of the cut end portion 13 immediately before the height position takes a discontinuous value can be the height position of the boundary position 13g. As a method of measuring the length Z of the collapse 13c, for example, there is a method of observing and measuring the shape profile of the cut end portion 13 by a profilometer or the like.

[0082] In the metal processed product 1 of the present embodiment, a protrusion 13h is provided at the lower portion of the coining surface 13e. The protrusion 13h is formed by causing the corner portion 13m (refer to Figure 9 ) of the cut end portion 13 on the lower surface 13b side to retreat to the inside in a direction orthogonal to the plate thickness direction T (the X-axis direction in the figure) in coining processing of forming the coining surface 13e.

[0083] The protrusion 13h has a height h0 of more than 0 mm and 0.20 mm or less. The metal processed product 1 is sometimes used in a manner such that the lower surface 13b of the cut end portion 13 is in contact with another structure. If the height h0 of the protrusion 13h is large, a space is generated between the lower surface 13b of the cut end portion 13 and the other structure, which becomes a cause of rattling. By the height h0 of the protrusion 13h being 0.20 mm or less, rattling caused by the protrusion 13h can be reduced. The height h0 can be a distance between the lower surface 13b of the cut end portion 13 and a lower end of the protrusion 13h in the plate thickness direction T of the cut end portion 13.

[0084] As shown in FIG. 1, the protrusion 13h is sometimes formed by flattening a burr portion 21a (a burr-shaped protrusion) generated in the cutting process by coining processing, and the plating layer 13k of the lower surface 13b of the cut end portion 13 is sometimes wound into the protrusion 13h. By making the height h of the burr portion 21a and a coining area Ar that is flattened by the coining processing both small, the amount of the plating layer 13k wound into the protrusion 13h can be suppressed to be small, and the generation of a whisker-like burr caused by the plating layer 13k falling off can be suppressed. Figure 7 In the metal processed member 1 of the present embodiment, as shown in FIG. 1, the plating layer 13k on the surface of the metal plate is wound from the lower surface 13b of the cut end portion 13 to an end surface of the cut end portion 13. The plating layer 13k of the lower surface 13b is pressed or compressed together with a portion constituting the coining surface 13e and is wound to the end surface of the cut end portion 13 when coining processing is performed. At least a portion of the coining surface 13e is covered with the plating layer 13k by this winding of the plating layer 13k. In the portion of the coining surface 13e covered with the plating layer 13k, the generation of red rust can be further suppressed.

[0085] Figure 6 In the metal processed member 1 of the present embodiment, as shown in FIG. 1, the plating layer 13k on the surface of the metal plate is wound from the lower surface 13b of the cut end portion 13 to an end surface of the cut end portion 13. The plating layer 13k of the lower surface 13b is pressed or compressed together with a portion constituting the coining surface 13e and is wound to the end surface of the cut end portion 13 when coining processing is performed. At least a portion of the coining surface 13e is covered with the plating layer 13k by this winding of the plating layer 13k. In the portion of the coining surface 13e covered with the plating layer 13k, the generation of red rust can be further suppressed.

[0086] In the metal processed member 1 of the present embodiment, the height Lc of the upper end of the plating layer 13k wound from the lower surface 13b of the cut end portion 13 in the plate thickness direction T with the lower surface 13b of the cut end portion 13 as a reference is 0.10 times or more of the radius of curvature R0 or the taper height C0 of the coining surface 13e. By the height Lc being 0.10 times or more of the radius of curvature R0 or the taper height C0, the generation of red rust can be more reliably suppressed. The radius of curvature R0 is a radius of curvature of an outer surface of the coining surface 13e when the coining surface 13e is an R surface (a curved chamfer surface) as shown in FIG. 1. The taper height C0 is a length along the plate thickness direction T between the lower surface 13b and the upper end of the coining surface 13e when the coining surface 13e is a taper surface (a planar chamfer surface) as shown in FIG. 1. These radius of curvature R0 or taper height C0 can be measured in a cross section of the cut end portion 13. Figure 5 Figure 2 As shown in FIG. 1, the protrusion 13h is sometimes formed by flattening a burr portion 21a (a burr-shaped protrusion) generated in the cutting process by coining processing, and the plating layer 13k of the lower surface 13b of the cut end portion 13 is sometimes wound into the protrusion 13h. By making the height h of the burr portion 21a and a coining area Ar that is flattened by the coining processing both small, the amount of the plating layer 13k wound into the protrusion 13h can be suppressed to be small, and the generation of a whisker-like burr caused by the plating layer 13k falling off can be suppressed.

[0087] ​​<Manufacturing method of metal processed product 1>

[0088] Next, Figure 9 is an explanatory view of a manufacturing method of the metal processed product 1 according to the embodiment of the present application. As Figure 9 indicated, the manufacturing method of the metal processed product 1 according to the embodiment includes a preparation step, a semi-cutting step, a fine-cutting step, and a fine-pressing step.

[0089] The preparation step is a step of preparing the first blank 2. The first blank 2 can be obtained by performing a forming process such as drawing processing on a plated metal plate in a flat plate shape. That is, the first blank 2 is made of a plated metal plate as a blank similarly to the metal processed product 1. The first blank 2 has a first flange portion blank 20 having an outer diameter larger than that of the flange portion 12 as indicated. Figure 1 The first flange portion blank 20 can have a circular shape in plan view, or a non-circular shape. As for the portions other than the first flange portion blank 20, the first blank 2 can have a shape equivalent to that of the metal processed product 1. In addition, the preparation step can not be accompanied by a forming process on a plated metal plate. A blank processed by a third party can be obtained by some method. The first flange portion blank 20 according to the embodiment constitutes a cut portion in a flat plate shape including a portion that becomes the cut end portion 13.

[0090] The semi-cutting step is a step of semi-cutting the first blank 2. In the semi-cutting step, semi-cutting of the first flange portion blank 20 (cut portion) is performed. Semi-cutting refers to a process of cutting the first flange portion body 20 halfway in the plate thickness direction of the first flange portion body 20. Here, a smooth surface smoothed by a side surface 31a of a punch for semi-cutting (first punch 31) becomes a first sheared surface 13d1. If the first flange portion blank 20 of the first blank 2 is semi-cut, a removal portion 20a that is finally outside the product is cut halfway from the first flange portion blank 20. Figure 10

[0091] The fine-cutting step is a step of performing cutting processing on the first flange portion blank 20 (cut portion) of the first blank 2 to obtain the second blank 3. The second blank 3 is an intermediate member for manufacturing the metal processed product 1, and the metal processed product 1 can be obtained by further applying processing to the second blank 3. In the fine-cutting step, the removal portion 20a of the first flange portion blank 20 is cut, and is separated from the first flange portion blank 20. By cutting the removal portion 20a, a second flange portion blank 30 is formed. Here, a side surface of a punch for fine-cutting (second punch 32) becomes a second sheared surface 13d2. Figure 13 ​the side surface 32a of the 2nd die 32) becomes a 2nd shearing surface 13d2. The 2nd flange portion blank 30 has a cut end portion 13. The cut end portion 13 of the 2nd blank 3 has a corner portion 13m on the lower surface 13b side. The corner portion 13m sometimes also has burrs and / or the protruding corner portion 21a (refer to Figure 13

[0092] The finish pressing process is a process of performing finish pressing processing on the cut end portion 13 of the 2nd blank 3 obtained in the finish cutting process to obtain the metal processed product 1. As will be described later using the drawings, the finish pressing processing of the present embodiment is processing of pressing the corner portion 13m of the cut end portion 13 of the 2nd blank 3 against the pad 7 to form a finish pressed surface 13e on the corner portion 13m. The finish pressed surface 13e is a surface in which the corner portion 13m is flattened. In the manufacturing method of the metal processed product 1 of the embodiment, the finish pressed surface 13e is formed on the corner portion 13m of the 2nd flange portion blank 30 of the 2nd blank 3, whereby the metal processed product 1 having the flange portion 12 is obtained. Figure 1 The screw hole 121 of the metal processed product 1 shown in FIG. 1 can be formed in the 1st flange portion blank 20 or the 2nd flange portion blank 30 at the stage of the 1st blank 2 or the 2nd blank 3, or can be formed in the flange portion 12 after the finish pressing process.

[0093] In the half cutting process and the finish cutting process of the manufacturing method of the metal processed product 1 of the present embodiment, a die and a punch are used to process the 1st flange portion blank 20 and the 2nd flange portion blank 30. Hereinafter, the details of the half cutting process and the finish cutting process will be described. The tip of the die and the punch is sometimes referred to as a "shoulder".

[0094] Further, in the following description, with respect to the die used in order to obtain the metal processed product 1, for the sake of convenience, the die on the side to be pressed in is referred to as a punch, and the die on the side to be pressed against is referred to as a punch. The die on the side to be pressed in is sometimes located above and sometimes located below with respect to the blank 2, 3. In the case of moving in the horizontal direction, the die on the side to be pressed in is also referred to as a punch, and the die on the side to be pressed against is also referred to as a punch. For example, Figure 2 The metal processed product 1 shown in FIG. 1 is a member obtained by cutting using the die on the upper side as the die on the side to be pressed in. In the case of using the die on the lower side as the die on the side to be pressed in, i.e., using the die on the lower side as a punch, the cut end portion 13 of the metal processed product 1 has a corner portion 13m on the upper surface 13a side. Figure 2 ​On the contrary, the collapsed edge 13c is located at the bottommost part of the cut end 13, and a shearing surface 13d and a sizing surface 13e are formed above it. When it is not clear which of the upper and lower (or left and right) molds is the die or the punch, after actually performing the cutting, observe the cut end 13, and the mold that presses the surface on the side where the collapsed edge 13c is located is called the die, and the mold that presses the surface on the opposite side is called the punch. In short, as described above, the upper surface 13a of the cut end 13 is defined as the surface on the side where the tip of the die is pressed into during the cutting process of the first flange blank 20 and the second flange blank 30, that is, the surface on the side where the collapsed edge 13c is located. In addition, the lower surface 13b of the cut end 13 is defined as the surface on the side where the tip of the die is withdrawn during the cutting process of the second flange blank 30.

[0095] <a. Semi-cutting process>

[0096] Figure 10 is a diagram showing Figure 9 the first die 31 and the first punch 41 used in the semi-cutting process. Figure 11 is an enlarged diagram showing Figure 10 the semi-cutting part 21. Figure 12 is a diagram showing the Figure 10 radius of curvature R of the tip of the first punch 41 P1 and the clearance C 31-41 during the change of the corner part 21a.

[0097] Figure 10 The upper part of shows the state just before the semi-cutting process, Figure 10 and the lower part of shows the state just after the semi-cutting process. As Figure 10 shown, in the semi-cutting process of the manufacturing method of the metal workpiece 1 in the present embodiment, the first die 31 and the first punch 41 are used to semi-cut the first blank 2 in the plate thickness direction to form the semi-cutting part 21. In Figure 10 , as one method of semi-cutting, a method of semi-cutting (semi-punching) the first flange blank 20 of the first blank 2 held by the first punch 41 and the first pressure plate 51 is shown. The first die 31 constitutes the cutting die that is pressed into the first flange blank 20 during semi-cutting. In the present embodiment, the mold that presses the part that becomes the flange 12 in the first flange blank 20 is set as the first punch 41, and the mold that presses the removed part 20a is set as the first die 31.

[0098] The clearance C between the first die 31 and the first punch 41 31-41 (mm) is a negative clearance. Among them, the clearance C 31-41 represents the clearance between the first die 31 and the first punch 41. Specifically, as Figure 10indicated by the distance between the side surface 31a of the first die 31 and the side surface 41a of the first punch 41. The clearance in a state where there is no clearance (i.e., C 31-41 zero) is referred to as a positive clearance, and the clearance in a state where the first die 31 and the first punch 41 partially overlap each other is referred to as a negative clearance. In the present specification, the clearance between the die and the punch is represented by a positive value for the positive clearance and by a negative value for the negative clearance.

[0099] As Figure 10 indicated, the first die 31 and the first punch 41 are arranged to partially overlap each other as viewed in the pressing direction of the first die 31 (i.e., the plate thickness direction of the flange portion 12, Z direction). Assuming that the clearance C 31-41 is set to the positive clearance, cracks generated from the cutting edge of the first die 31 and the first punch 41 as in the blanking process performed at one time meet each other, and it is possible that the removed portion 20a is completely cut off from the first flange portion blank 20. In addition, the burr 13c of the cut end portion 13 increases. By setting the clearance C 31-41 to the negative clearance, it is possible to avoid that the removed portion 20a is completely cut off from the first flange portion blank 20 in the half-cutting process, and to reduce the burr 13c.

[0100] In addition, by setting the clearance C 31-41 to the negative clearance, a larger hydrostatic stress is generated in the region sandwiched by the first die 31 and the first punch 41. Therefore, among the stresses generated when the first die 31 is pressed into the first flange portion blank 20, the proportion of the tensile stress generated between the material that becomes the waste (i.e., the removed portion 20a) after the cutting process and the flange material that becomes the flange portion 12 decreases. As a result, the material that comes into contact with the tip of the cutting edge of the first die 31 after the cutting process easily flows from the tip of the cutting edge of the first die 31 to the side surface 31a side of the first die 31, and it is possible to increase the wrapping of the plating layer 13f around the shear surface 13d. In addition, since the proportion of the tensile stress decreases and the compressive stress increases, the material that originally flows to the side that becomes the waste is pushed back to the side that becomes the flange portion 12. As a result, the portion that becomes the burr 13c after the cutting process is also filled with the material, and it is possible to reduce the burr 13c.

[0101] In the adjacent direction of the first die 31 and the first punch 41 (in the Figure 10In the X direction (where X is the center), the shorter the length of the material that becomes scrap after cutting, the easier it is for the material to flow from the tip of the first die 31 to the side 31a of the first die 31. Therefore, it is preferable to arrange the first die 31 such that the side 31a of the first die 31 is within a range of less than twice the thickness t1 of the first flange blank 20 (i.e., flange 12) from the end of the first flange blank 20, and to perform a partial cut.

[0102] The gap C between the first die 31 and the first punch 41 31-41 [mm] Preferably, the following formula (a1) is satisfied.

[0103] -0.35×t1≤C 31-41 ≤-0.0125×t1···(a1)

[0104] Wherein, t1 is the plate thickness (mm) of the half-cut-off portion of the first blank 2. In this embodiment, the half-cut-off portion of the first blank 2 is the first flange blank 20.

[0105] If the gap C 31-41 If the thickness t1 of the first flange body 20 is -0.0125 times or less, a large hydrostatic stress is generated in the area clamped by the first die 31 and the first punch 41, and the proportion of tensile stress is reduced. As a result, cracks are not generated during partial cutting and complete cutting occurs, and a large fracture surface is not generated, thus avoiding the complete removal of portion 20a from the first flange body 20 during the partial cutting process. On the other hand, if the gap C 31-41 If the thickness of the blank 20 in the first flange portion is -0.35 times or more than t1, the forming load required for partial cutting will not increase, nor will it exceed the stamping capacity. Therefore, the burden on the die is also small, which can suppress the reduction of die life. Clearance C 31-41 More preferably, the gap C is less than or equal to -0.10 times or less than -0.15 times the plate thickness t1 of the first flange body 20. 31-41 It can also be more than -0.30 times or more than -0.25 times the plate thickness t1 of the main body 20 of the first flange portion.

[0106] like Figure 10 As shown, the cutting tips of the first die 31 and the first punch 41 are configured to have a specified radius of curvature R. D1 R P1 The R shape is (mm).

[0107] The radius of curvature R of the cutting tip of the first punch die 31 D1 (mm) Preferably, the following formula (a2) is satisfied.

[0108] 0.10×t1≤R D1 ≤1.50···(a2)

[0109] The radius of curvature R of the tip of the first punch 41 P1 (mm) preferably satisfies the following equation (a3).

[0110] 0.10 x t1≤ R P1 ≤ 3.00 (a3)

[0111] If the radius of curvature R D1 is 0.10 times or more of the plate thickness t1, the plated layer 13f is not cut off and a large hydrostatic stress is not generated in the negative clearance, and the material that becomes the scrap (i.e., the removed portion 20a) directly below the first punch 31 can flow from the tip of the first punch 31 to the side surface 31a side of the first punch 31. If the radius of curvature R P1 is 0.10 times or more of the plate thickness t1, the first punch 31 can be pressed deeper into the first flange portion blank 20, and thus the material that becomes the scrap (i.e., the removed portion 20a) directly below the first punch 31 can flow from the tip of the first punch 31 to the side surface 31a side of the first punch 31. By this flow, the proportion of the tensile stress that occurs between the material that becomes the scrap after the cutting and the flange material that becomes the flange portion 12 in the stress that occurs when the first punch 31 is pressed into the first flange portion blank 20 decreases. As a result, the plated layer 13f can be wound around the shear plane 13d.

[0112] On the other hand, if the radius of curvature R D1 is set to 1.50 mm or less, the amount of material that is located at the tip of the first punch 31 at the time of the half-cutting decreases, and the generation of a fracture surface can be reduced in the subsequent finish cutting. Furthermore, if the radius of curvature R P1 is set to 3.00 mm or less, the occurrence of a plated layer drop, i.e., the occurrence of a burr, after the subsequent finish pressing and the increase in the height h0 of the protrusion 13h of the corner portion at the lower portion of the finish pressed surface 13e can be prevented.

[0113] In addition, by setting the tips of the first punch 31 and the first punch 41 to be R-shaped, the amount of cutting of the first flange portion blank 20 in the half-cutting process can be increased compared to a case in which only the tip of one of the first punch 31 or the first punch 41 is set to be R-shaped. That is, by setting the tips of the first punch 31 and the first punch 41 to be R-shaped, the plate thickness t2 (mm) of the half-cut portion 21 of the first blank 2 can be decreased compared to a case in which only the tip of one of the first punch 31 or the first punch 41 is set to be R-shaped. Furthermore, as described above, by setting the tips of the first punch 31 and the first punch 41 to be R-shaped, the plated layer 13f can be wound around the shear plane 13d. Figure 10As shown in the lower part, the plate thickness t2 of the half-cut portion 21 of the first blank 2 (first flange blank 20) ​​is equivalent to the separation distance along the pressing direction of the first die 31 when the first die 31 is pressed into the lower dead point, between the connection position of the cutting tip of the first die 31 and the side surface 31a and the upper surface 41b of the cutting tip of the first punch 41 that contacts the lower surface 2b of the first blank 2. It can also be said to be the residual plate thickness of the removed portion 20a in the half-cut portion 21.

[0114] If only the tip of the first die 31 is set to an R-shape, and the pressing amount D of the first die 31 is set to be greater than or equal to the plate thickness t1 of the flange portion 12, then the tip of the first die 31 will contact the tip of the first punch 41. In this case, it is impossible to set the pressing amount D of the first die 31 to be greater than or equal to the plate thickness t1 of the flange portion 12. Furthermore, if... Figure 10 As shown, the pressing amount D is the amount of movement of the first die 31 from the position where the first die 31 contacts the upper surface of the first flange portion blank 20 of the first blank 2 to the position where the pressing of the first die 31 stops (hereinafter, this position will also be referred to as the "bottom stop").

[0115] On the other hand, if the cutting tips of the first die 31 and the first punch 41 are set to an R shape, then as Figure 11 As shown, the amount that the first die 31 can press in until the tip of the first punch 31 contacts the tip of the first punch 41 is increased. Therefore, by setting both the tips of the first die 31 and the first punch 41 to an R shape, the pressing amount D of the first die 31 can be set to be greater than or equal to the plate thickness t1 of the flange portion 12, which can further increase the cutting amount of the first flange portion blank 20 in the semi-cutting process and increase the proportion of the shearing surface 13d in the cut end 13. As a result, the plating layer 13f can be wrapped more around the shearing surface 13d, and the proportion of the cut end 13 covered by the plating layer 13f can be increased. In addition, by reducing the residual plate thickness t2, the cutting amount in the fine cutting process is reduced, and the state of no plating residue in the finely cut area can be avoided. The residual plate thickness t2 can also be set to 0.30 times or less of the plate thickness t1 [mm] of the first flange portion blank 20.

[0116] The pressing amount D (mm) of the first die 31 relative to the half-cut portion 21 (the blank of the first flange portion 20) preferably satisfies the following formula (a4).

[0117] 1.00×t1 <D≤t1+1.00···(a4)

[0118] The distance C between the first die 31 and the first punch 41 at the lower stop point D1-P1 (mm) Preferably, the following formula (a5) is satisfied.

[0119] 0.20≤C D1-P1(a5)

[0120] If the press-in amount D is greater than 1.00 times the plate thickness tl, it is difficult to generate a fracture surface in the subsequent finish cutting. On the other hand, if the press-in amount D is 1.00 mm or less, the height h of the corner portion 21a can be reduced. Therefore, it is easy to suppress the peeling of the plating layer, i.e., the generation of a whisker, after the finish press working, and it is easy to make the height ho of the protrusion portion 13h of the lower portion of the finish press surface 13e 0.20 mm or less.

[0121] On the other hand, by ensuring that the gap C between the first punch 31 and the first punch 41 at the bottom dead center is 0.20 mm or more, it is possible to avoid the generation of a crack in the half-cutting and to locally generate a complete cut. Furthermore, the gap C between the first punch 31 and the first punch 41 at the bottom dead center is set to the minimum value of the gap. D1-P1 D1-P1

[0122] As Figure 11 particularly shown, the corner portion 21a having a height h (mm) is formed in the half-cutting portion 21. The height h (mm) corresponds to the separation distance in the press-in direction of the first punch 31 of the position on the tip of the first punch 41 on the extension line of the side surface 31a of the first punch 31 and the extension line of the upper surface 41b of the first punch 41 that contacts the lower surface 2b of the first blank 2, and is expressed by the following formula. That is, the height h (mm) of the corner portion 21a is determined by the curvature radius R P1 (mm) of the tip of the first punch 41 used in the half-cutting process and the gap C 31-41 (mm) between the first punch 31 and the first punch 41.

[0123] [Mathematical Formula 2]

[0124]

[0125] The height h can be derived as follows. That is, as shown in the drawing, when the line segment "X" is placed, according to the Pythagorean theorem, the following formula (1) is obtained. Figure 12

[0126] R P1 2 = (R P1 - |C 31-41 |) 2 + X 2 ··· (1)

[0127] When formula (1) is solved for X, the following formula (2) is obtained.

[0128] [Mathematical Formula 3]

[0129] ​​​

[0130] where, since h = R P1 -X, substituting X in Equation (2) into this equation gives the above equation for the height h.

[0131] The radius of curvature R of the tip of the first punch 41 P1 is larger, and the gap C 31-41 is closer to a positive gap, the height h of the protruding corner portion 21a is higher. Figure 12 (b) schematically shows the protruding corner portion 21a when the radius of curvature R of the tip of the first punch 41 P1 is larger than that in Figure 12 (a). Figure 12 (c) schematically shows the protruding corner portion 21a when the radius of curvature R of the tip of the first punch 41 P1 is larger than that in Figure 12 (a) and the gap C 31-41 is closer to a positive gap. As shown in Figure 13 (a) - (c), the larger the height h of the protruding corner portion 21a, when the first blank 2 is set in the die (the second die 32 and the second punch 42) for precision cutting, the lower surface 2b of the first blank 2 floats from the upper surface 42b of the second punch 42 through the protruding corner portion 21a.

[0132] <b. Precision cutting process>

[0133] Next, Figure 9 is an explanatory diagram showing the second die 32 and the second punch 42 used in the Figure 13 precision cutting process. Figure 13 The upper part of Figure 13 shows the state before precision cutting, and the lower part of

[0134] shows the state just after precision cutting. Figure 13 In the precision cutting process, as shown in Figure 10 , the first flange blank 20 having a semi - cut portion 21 is precision - cut using the second die 32 and the second punch 42. In

[0135] , as one method of precision cutting, a method of punching out the second flange blank 30 from the first flange blank 20 clamped by the second punch 42 and the second pressure plate 52 is shown. The second die 32 constitutes the cutting die pressed into the first flange blank 20 in precision cutting. In this embodiment, the die pressing the portion that becomes the flange portion 12 in the first flange blank 20 is the second punch 42, and the die pressing the removed portion 20a is the second die 32. The second die 32 can also be the same as the first die 31. That is, the first die 31 used in the semi - cutting process can also be used as the second die 32 in the precision cutting process.​​​The positional relationship of the second die 32 to the first blank 2 and the positional relationship of the first die 31 to the first blank 2 are preferably the same. In the case where they are not the same, for example, if the diameter of the second die 32 is larger than the diameter of the first die 31, a step is generated at the cut end portion 13. In contrast, for example, if the diameter of the second die 32 is smaller than the diameter of the first die 31, the second die 32 comes into contact with the semi-cut cut end portion 13 generated in the semi-cutting process, and the second die 32 can possibly chip off the plating layer 13f wound into the shearing surface 13d. The positional relationship of the second punch 42 to the first blank 2 is preferably such that the diameter of the second punch 42 is smaller than the diameter of the first die 31. However, if it is smaller than the diameter of the second die 32, it is not problematic even if the diameter of the second punch 42 is the same as the diameter of the first die 31. In contrast, if the diameter of the second punch 42 is larger than the diameter of the first die 31, a step is generated at the cut end portion 13.

[0136] The finish cutting of the present embodiment is performed from the same direction as the semi-cutting. That is, as shown in FIG. 6, in the semi-cutting, the first die 31 is pressed into the first flange portion blank 20 from the upper surface side of the first flange portion blank 20, and as shown in FIG. 7, in the finish cutting, the second die 32 is also pressed into the first flange portion blank 20 from the upper surface side of the first flange portion blank 20. Thus, the removal portion 20a is separated from the first flange portion blank 20, and the second blank 3 having the cut end portion 13 is obtained. Figure 13 Figure 10 As shown in FIG. 7, in the finish cutting, the second die 32 is also pressed into the first flange portion blank 20 from the upper surface side of the first flange portion blank 20. Thus, the removal portion 20a is separated from the first flange portion blank 20, and the second blank 3 having the cut end portion 13 is obtained.

[0137] The clearance C of the second die 32 and the second punch 42 32-42 [mm] is a positive clearance. The clearance C of the second die 32 and the second punch 42 32-42 is expressed by the distance of the side surface 32a of the second die 32 and the side surface 42a of the second punch 42. Here, as in the semi-cutting process, the clearance in the state where the second die 32 and the second punch 42 are separated is referred to as a positive clearance, and the clearance in the state where the second die 32 and the second punch 42 are partially overlapped is referred to as a negative clearance.

[0138] The clearance C of the second die 32 and the second punch 42 32-42 (mm) is a positive clearance. The clearance C of the second die 32 and the second punch 42 32-42 The following expression (bl) is preferably satisfied.

[0139] 0.01 ≤ C 32-42 ≤ 0.20 x t2 · · · (bl)

[0140] where, as described above, t2 is the plate thickness of the semi-cut portion 21 of the first blank 2 (the first flange portion blank 20), and t1 is the plate thickness of the first flange portion blank 20. Figure 13 ​As shown in the lower part, the distance between the connection position of the tip of the first die 31 and the side surface 31a when the first die 31 is pressed into the lower stop point and the separation distance of the upper surface 41b of the tip of the first punch 41 that contacts the lower surface 2b of the first blank 2 along the pressing direction of the first die 31, can also be said to be the residual plate thickness of the removed portion 20a in the half-cut portion 21.

[0141] If the gap C 32-42 If the gap is 0.01mm or greater, then even if sliding accuracy issues arise in the stamping machinery or eccentricity of the die during precision cutting, there is no need to worry about the second die 32 contacting and breaking with the second punch 42. On the other hand, if the gap C 32-42 If the thickness is less than 0.20 times the plate thickness t2, it is difficult to generate burrs. Here, the smooth surface of the end face smoothed by the side surface 32a of the second die 32 becomes the second shear surface 13d2.

[0142] The cutting tip of the second die 32 is set to have a specified radius of curvature R. D2 The R shape (mm). For example... Figure 13 As shown, the second die 32 is pressed into the portion where the first flange blank 20 is precisely cut off; therefore, the cutting tip of the second die 32 is set to have a radius of curvature R. D2 The R-shape. Furthermore, the tip of the second punch 42 is like... Figure 14 The diagram shows a square shape without any arcs. In this case, the tip of the second punch 42 can have a radius of curvature 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 tip of the second punch 42 can be less than 0.10 times the plate thickness t1 of the first flange portion of the first blank 2, or, as needed, less than 0.06 times, less than 0.04 times, or less than 0.02 times.

[0143] The radius of curvature R of the cutting tip of the second die 32 D2 (mm) Preferably, the following formula (b2) is satisfied.

[0144] 0.25≤R D2 ≤1.50×t2···(b2)

[0145] If the radius of curvature R D2 If the thickness is 0.25mm or greater, the second die 32 will not cut off the plating 13f that wraps around the shear surface 13d. On the other hand, if the radius of curvature R... D2 If the thickness is less than 1.50 times the plate thickness t2, it is difficult to generate burrs.

[0146] Further, in the case where the cut end portion 13 is formed on the outer periphery side of the metal processed product 1, the inner diameter D32 of the second punch 32 is equal to or greater than the inner diameter D31 of the first punch 31, and in the case where the cut end portion 13 is formed on the inner periphery side of the metal processed product 1, the outer diameter d32 of the second punch 32 is equal to or smaller than the outer diameter d31 of the first punch 31. Specifically, in the case where the cut end portion 13 is formed on the outer periphery side of the metal processed product 1, the absolute value |D32-D31| of the difference between the inner diameter D31 of the first punch 31 and the inner diameter D32 of the second punch 32 is preferably 1.00 mm or less. In the case where the cut end portion 13 is formed on the inner periphery side of the metal processed product 1, the absolute value |d32-d31| of the difference between the outer diameter d31 of the first punch 31 and the outer diameter d32 of the second punch 32 is preferably 1.00 mm or less. Thus, it is possible to reduce the step generated at the cut end portion 13 of the metal processed product 1 due to the difference D32-D31 or d32-d31 between the punches 31, 32 for implementing the two processes of the half-cut process and the finish-cut process, and it is possible to obtain a good cut cross section.

[0147] Further, in the case where the cut end portion 13 is formed on the outer periphery side of the metal processed product 1, the inner diameter D32 of the second punch 32 is equal to or greater than the inner diameter D31 of the first punch 31, and in the case where the cut end portion 13 is formed on the inner periphery side of the metal processed product 1, the outer diameter d32 of the second punch 32 is equal to or smaller than the outer diameter d31 of the first punch 31. Specifically, in the case where the cut end portion 13 is formed on the outer periphery side of the metal processed product 1, the absolute value |D32-D31| of the difference between the inner diameter D31 of the first punch 31 and the inner diameter D32 of the second punch 32 is preferably 1.00 mm or less. In the case where the cut end portion 13 is formed on the inner periphery side of the metal processed product 1, the absolute value |d32-d31| of the difference between the outer diameter d31 of the first punch 31 and the outer diameter d32 of the second punch 32 is preferably 1.00 mm or less. Thus, it is possible to reduce the step generated at the cut end portion 13 of the metal processed product 1 due to the difference D32-D31 or d32-d31 between the punches 31, 32 for implementing the two processes of the half-cut process and the finish-cut process, and it is possible to obtain a good cut cross section.

[0148] The protrusion 21a remains on the lower portion of the second flange portion blank 30 after the finish cutting. The higher the height h of the protrusion 21a after the half cutting, the larger the protrusion 21a remains after the finish cutting.

[0149] <c. finish pressing process>

[0150] Next, Figure 9is a photograph showing the cut end portion 13 of the metal work 1 after the coining process. As shown in Figure 15 is a diagram showing the pad 7 and the coining block 8 used in the coining process, Figure 14 is a photograph showing the cut end portion 13 of the metal work 1 after the coining process. As shown in Figure 11 the cut end portion 13 of the second blank 3 is sandwiched by the pad 7 and the coining block 8. The pad 7 has a longitudinal wall surface 70, a bottom wall surface 71, and a pressing surface 72.

[0151] The longitudinal wall surface 70 is arranged so as to be opposed to and substantially parallel with the sheared surface 13d of the second blank 3 when the cut end portion 13 of the second blank 3 is sandwiched by the pad 7 and the coining block 8. The longitudinal wall surface 70 is arranged so as to be parallel with the advancing and retreating direction (Z direction in Figures 2-6 ) of the coining block 8.

[0152] The bottom wall surface 71 is arranged so as to be opposed to the coining block 8 across the second blank 3 in the plate thickness direction T of the cut end portion 13. The bottom wall surface 71 extends in a direction orthogonal to the longitudinal wall surface 70 below the longitudinal wall surface 70 (i.e., on the side opposite to the coining block 8).

[0153] The pressing surface 72 is a surface connecting the longitudinal wall surface 70 and the bottom wall surface 71 at the corner where the longitudinal wall surface 70 and the bottom wall surface 71 abut. The pressing surface 72 is provided in order to form a coining surface (coining surface 13e of the second blank 3) in the second blank 3, and is formed in a planar shape or a curved shape corresponding to the shape of the coining surface. For example, as shown in Figures 2-4 , in a case where the coining surface 13e is a planar chamfer surface (hereinafter referred to as a “taper surface”), as shown in Figure 14 , the pressing surface 72 is planar and inclined with respect to the longitudinal wall surface 70 and the bottom wall surface 71. On the other hand, as shown in Figure 5 , in a case where the coining surface 13e of the second blank 3 is a curved chamfer surface (hereinafter referred to as an “R surface”), the pressing surface 72 is a concave curved surface. Figure 14

[0154] In the coining process, as shown in Figures 2-5 ​As shown, in a state where the cut end portion 13 of the second blank 3 opposes the longitudinal wall surface 70 of the pad 7, the second blank 3 is sandwiched in the plate thickness direction T by the press block 8 and the bottom wall surface 71 of the pad 7. Then, the press block 8 is pressed toward the bottom wall surface 71, and the second blank 3 is pressed down to a position where the lower surface 13b of the second blank 3 contacts the bottom wall surface 71. At this time, before the lower surface 13b of the second blank 3 contacts the bottom wall surface 71, the corner portion 13m or the protruding corner portion 21a is pressed against the pressing surface 72. After the corner portion 13m or the protruding corner portion 21a is pressed against the pressing surface 72, the press block 8 is further pressed, and the lower surface 13b of the second blank 3 contacts the bottom wall surface 71. In this process, the corner portion 13m or the protruding corner portion 21a is flattened by the pressing surface 72, and a press surface 13e is formed Figure 15 . The cut end portion 13 of the metal product 1 after the pressing process is, for example, in a state shown in a photograph Figures 2-6 .

[0155] The press surface 13e is a smooth surface into which the surface of the pressing surface 72 is transferred, and is less likely to generate red rust than a rough surface-like fractured surface. It is considered that this is because, by the surface roughness becoming smooth, moisture is difficult to remain in the press surface 13e. In addition, it is considered that the plating layer 13k on the lower surface 13b side of the cut end portion 13 is also a factor in that red rust is less likely to be generated in the press surface 13e.

[0156] On the other hand, in the press working that forms the press surface 13e, the material of the corner portion 13m of the cut end portion 13 retreats to the inside in a direction orthogonal to the plate thickness direction T (the X-axis direction in the drawing), and thereby a protruding portion 13h is formed (see Figure 7 ). As described above, when the height h0 of the protruding portion 13h is large, a space is generated between the lower surface 13b of the cut end portion 13 and the other structure, and becomes a cause of rattling. In addition, as shown in Figure 1 , sometimes the plating layer 13k of the protruding corner portion 21a of the cut end portion 13 is rolled into the protruding portion 13h, and sometimes a whisker-like burr is generated due to the plating layer 13k rolled into the protruding portion 13h falling off.

[0157] The present inventors and others conducted experiments in which the conditions of the cutting and press working were changed in various ranges, and investigated the height h0 of the protruding portion 13h and the generation state of the whisker-like burr. As a result, it was found that the height h0 of the protruding portion 13h and the generation state of the whisker-like burr have a correlation with the height h of the protruding corner portion 21a after the half-cut (before the finish cutting) and the press area Ar of the pad 7 used in the press process. Furthermore, sometimes a burr is generated due to the finish cutting conditions, but since the amount of the burr is small, it does not become a cause of the generation of the whisker-like burr in the press in the subsequent process.

[0158] In the manufacturing method of the metal product 1 of the embodiment of the present application, the press area Ar is set to satisfy the following equation.

[0159] h≤-1.09Ar+1.04

[0160] h is the height (mm) of the protruding corner 21a after partial cutting, and Ar is the precision pressing area (mm²) of the pad 7 used in the precision pressing process. 2 By setting the pressing area Ar in a manner that satisfies the formula, the height h0 of the protrusion 13h can be 0.20 mm or less. The method for manufacturing the metal workpiece 1 in the embodiments of the present invention can sometimes be understood to include the steps of setting the height h of the semi-cut protrusion 21a and the pressing area Ar in a manner that satisfies the above formula.

[0161] Furthermore, in the method for manufacturing the metal workpiece 1 according to an embodiment of the present invention, the precision pressing area Ar is preferably set to satisfy the following formula.

[0162] h≤1.20Ar 2 -2.07Ar +0.90

[0163] As mentioned above, h is the height (mm) of the protruding corner 21a after partial cutting, and Ar is the precision pressing area (mm²) of the pad 7 used in the precision pressing process. 2 By setting the pressing area Ar to satisfy this formula, the generation of burrs can be avoided. The method of manufacturing the metal processed article 1 in the embodiments of the present invention can sometimes be understood to include the steps of setting the height h of the semi-cut protruding corner portion 21a and the pressing area Ar in a manner that satisfies the above formula.

[0164] <Processed Product Examples>

[0165] In the above embodiments, the metal processed article 1 is... Figure 16 The case of the motor housing shown has been described, but the metal workpiece 1 manufactured by the workpiece manufacturing method of this embodiment can be any article made of plated metal sheet as blank and having a cut end 13. Examples of metal workpiece 1 include sheet metal, deep-drawn workpieces with flange 12, flanged workpieces with flange 12, protruding workpieces with flange 12, bent workpieces, various washers, plates, gears, springs and other stamped workpieces.

[0166] Metal processed products 1 can also be, for example, Figure 17 A circular flat washer 900 as shown. Alternatively, the metal workpiece 1 could also be, for example, a... Figure 18 Flat washers 910A, 910B, and 910C with teeth 911, as shown. Alternatively, the metal workpiece 1 could also be, for example... Figure 18 A circular disc spring 920 with the waveform shown. Figure 16The disc spring 920 can be manufactured, for example, by machining the flat washer 900 shown in Figure 19 into a wave shape. Also, the metal work product 1 can be, for example, a disc spring 930 having a tooth portion 931 as shown in Figures 16-19 .

[0167] When the metal work product 1 is a variety of plate members in a ring shape as shown in Figure 16 , the outer peripheral portion and the inner peripheral portion become the cut end portions 13.

[0168] For example, in order to cover the sheared surface of the inner peripheral surface and the outer peripheral surface of the flat washer 900 shown in Figure 20 with a plating layer, a cutting die shown in Figure 21 and Figure 20 is used for machining. Figure 21 is a schematic view showing an example of a cutting die for machining the flat washer 900. Figure 20 is a schematic view showing a state in which the blank 9 is subjected to blanking machining by the cutting die of Figure 20 .

[0169] Figure 23 The cutting die shown in Figure 21 is a die for manufacturing a metal work product 90 in a ring shape such as the flat washer 900, and has a hollow cylindrical punch 65 that supports the blank 9 (see ) in a circular plate shape, a punch in a cylindrical shape (hereinafter referred to as "inner punch") 63, and a punch in a hollow cylindrical shape (hereinafter referred to as "outer punch") 61. The outer punch 61 and the inner punch 63 are disposed in opposition to the punch 65, and the blank 9 is cut by pressing the outer punch 61 and the inner punch 63 into the blank 9 supported by the punch 65. The inner diameter of the outer punch 61 corresponds to the outer diameter of the metal work product 90, and the outer diameter of the inner punch 63 corresponds to the inner diameter of the metal work product 90. The cutting edges of the inner peripheral surface of the outer punch 61 and the outer peripheral surface of the inner punch 63 have an R shape with a radius of curvature. On the other hand, the cutting edges of the inner peripheral surface and the outer peripheral surface of the punch 65 do not have an R shape.

[0170] If the blank 9 is subjected to fine cutting by such a cutting die, as shown in Figure 22 , the portion 9a on the outer side than the outer peripheral surface 91 of the metal work product 90 is cut by the outer punch 61, and the portion 9b on the inner side than the inner peripheral surface 92 of the metal work product 90 is cut by the inner punch 63.

[0171] Figure 20 The fine pressing die shown in Figure 16The die shown after the cutting of the die performs coining processing on the cut end portion 9c of the blank 9, and has a pad 7 and a coining block 8. The pad 7 has a bottom portion 75, a central protrusion 76 protruding from the bottom portion 75, and a side peripheral portion 77. The outer peripheral surface of the central protrusion 76 and the inner peripheral surface of the side peripheral portion 77 constitute the longitudinal wall surface 70, and the upper surface of the bottom portion 75 constitutes the bottom wall surface 71 described above. A pressing surface 72 is formed between the bottom wall surface 71 and the longitudinal wall surface 70. The coining block 8 can be a ring-shaped body. The central protrusion 76 is made to pass through the hole portion 9d of the blank 9 formed in a ring shape by the cutting, and the blank 9 is pressed down by the coining block 8, whereby coining processing can be performed on the cut end portion 9c of the blank 9. By these cutting and coining processes, a metal processed product 90 (flat washer 900) as shown can be formed. Figure 23 The drawing illustrates the coining processing, and the mechanism for discharging the product from the die after the processing is omitted.

[0172] Further, the metal processed product 1 can also be, for example, Figure 10 a round plate-shaped plate 940 as shown.

[0173] The preferred embodiments of the present application have been described in detail above with reference to the accompanying drawings, but the present application is not limited to the example. It will be obvious to a person having ordinary knowledge in the technical field to which the present application pertains that various modifications or changes can be made within the scope of the technical idea described in the claims, and these are of course construed to fall within the technical scope of the present application.

[0174] Example

[0175] The present disclosure will be described more specifically below by way of examples. The present application is not limited to these examples.

[0176] As shown in Tables 1 to 3 below, the present inventors and others produced a plurality of processed product samples by varying the conditions of the semi-cutting, fine-cutting, and coining processes within various ranges. As the first blank 2, a flat plate-shaped Zn-6% Al-3% Mg (mass ratio) alloy plated steel plate having a plate thickness of 3.2 mm was used. The plated adhesion amount of the steel plate was 90 g / m 2 (one side).

[0177] [Table 1]

[0178]

[0179] [Table 2]

[0180]

[0181] [Table 3]

[0182]

[0183] (Semi-cutting process)

[0184] pass Figure 10 The method shown performs a partial cutting process on the first blank 2. The partial cutting process is achieved by pressing the first blank 2, held by the first punch 41 and the first pressure plate 51, into the first die 31. The first die 31 is an annular body with a circular hole having an inner diameter of 85.00 mm. The first punch 41 is cylindrical and can pass through the circular hole of the first die 31. The outer diameter of the first punch 41 is determined according to the clearance C shown in Table 1. 31-41 The changes are as follows: The cutting tips of the first die 31 and the first punch 41 have a radius of curvature R as shown in Table 1. D1 R P1 The R-shape. The pressing 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. D1-P1 As shown in Table 1.

[0185] After the partial cutting process, the partial cut portion 21 formed on the first blank 2 was measured (see reference). Figure 11 The plate thickness t2 is calculated. The measurement results are shown in Table 2. Furthermore, the height h of the protruding corner 21a of the half-cut portion 21 formed in the first blank 2 is calculated using the above formula (refer to...). Figure 13 The calculation results are shown in Table 1.

[0186] In addition, the formulas (a1) to (a5) related to the semi-cutting process in the table are shown below.

[0187] -0.35×t1≤C 31-41 ≤-0.0125×t1···(a1)

[0188] Where t1 is the plate thickness (mm) of the half-cut portion of the first blank 2, and C 31-41 It is the gap (mm) between the first die 31 and the first punch 41.

[0189] 0.10×t1≤R D1 ≤1.50···(a2)

[0190] Among them, R D1 It is the radius of curvature (mm) of the tip of the first die 31.

[0191] 0.10×t1≤R P1 ≤3.00···(a3)

[0192] Among them, R P1 It is the radius of curvature (mm) of the tip of the first punch 41.

[0193] 1.00×t1 <D≤t1+1.00···(a4)

[0194] Where t1 is the plate thickness (mm) of the half-cut portion of the first blank 2, and D is the pressing amount (mm) of the first punch 31 relative to the half-cut portion 21.

[0195] 0.20≤C D1-P1 ···(a5)

[0196] Among them, C D1-P1 It is the distance (mm) between the first die 31 and the first punch 41 at the lower dead center.

[0197] In Tables 1 and 2, in the columns indicating whether various conditions are met, "Yes" means that these conditions are met, and "No" means that these conditions are not met.

[0198] (Precision cutting process)

[0199] pass Figure 14 The method shown performs a fine cutting process on the first blank 2 after the semi-cutting process to obtain the second blank 3. Fine cutting is performed by pressing the first blank 2, held by the second punch 42 and the second pressure plate 52, into the second die 32. The second die 32 is an annular body with a circular hole having an inner diameter of 85.00 mm. The second punch 42 is formed as a cylinder capable of passing through the circular hole of the second die 32. The outer diameter of the second punch 42 is determined according to the gap C shown in Table 2. 32-42 The change is as follows: The tip of the second die 32 has a radius of curvature R as shown in Table 2. D2 The R-shape. The tip of the second punch 42 is a square without a rounded edge.

[0200] The equations (b1) and (b2) related to the precision cutting process in the table are shown below.

[0201] 0.01≤C 32-42 ≤0.20×t²···(b1)

[0202] Among them, C 32-42 t2 is the gap (mm) between the second die 32 and the second punch 42, and t2 is the thickness of the half-cut portion 21 of the first blank 2.

[0203] 0.25≤R D2 ≤1.50×t2···(b2)

[0204] Among them, R D2 It is the radius of curvature (mm) of the tip of the second die 32.

[0205] (Precision pressing process)

[0206] For the second blank 3 obtained in the precision cutting process, through Figure 24The method shown performs a coining process to obtain a processed product sample. The coining process is performed by pressing the corner portion 13m of the cut end portion 13 of the second blank 3 against the pressing surface 72 of the pad 7. The pressing surface 72 of the pad 7 is planar or curved as shown in Table 2. The coining area Ar is changed as shown in Table 2.

[0207] (Investigation of the processed product sample)

[0208] For the cut end surface of the processed product sample obtained by the above-described processes, the inclination angle Θd1 [°] of the first shear surface 13d1, the inclination angle Θd2 [°] of the second shear surface 13d2, the plating component residual length L1 [mm], the burr length Z [mm], the radius of curvature R0 [mm] or the taper height C0 [mm] of the coining surface 13e, the height Lc [mm] of the upper end of the plated layer 13k, the height h0 [mm] of the protrusion 13h, the presence or absence of a whisker-like burr, and the presence or absence of a burr were investigated. The results are shown in Table 3.

[0209] Further, regarding the presence or absence of a whisker-like burr, a case where the whisker-like burr is peeled off due to coining was evaluated as "Yes". Regarding the presence or absence of a burr, a case where the burr is flattened by coining was evaluated as "No", and a case where the burr is not flattened and floats even if coining is performed, or a case where the burr is peeled off after coining was evaluated as "Yes". Here, a portion where the plating component is peeled off is referred to as a whisker-like burr, and a portion where the steel base material of the steel sheet is the main component is referred to as a burr.

[0210] Inventive Examples 1 to 18 in the table are examples in which the height h0 of the protrusion 13h in the cut end surface of the processed product sample is 0.20 mm or less. Comparative Examples 1 to 5 are examples in which the height h0 of the protrusion 13h in the cut end surface of the processed product sample exceeds 0.20 mm, or the processing is discontinued in the half-cutting or finish-cutting. In Inventive Examples 1 to 18 and Comparative Examples 1 to 5, regarding the half-cutting process, the gap C 31-41 (mm) between the first punch 41 and the first die 31 was set to a negative gap, and the tip of the first punch 41 and the tip of the first die 31 were provided in an R shape having a prescribed radius of curvature R D1 , R P1 (mm).

[0211] Here, Figure 24 is a graph showing the relationship between the height h of the protrusion corner portion 21a after the half-cutting (before the finish-cutting) and the coining area Ar of the pad 7 used in the coining process in the examples. Figure 11 The vertical axis of the graph shown is the height h (mm) of the protrusion corner portion 21a after the half-cutting. Regarding the height h of the protrusion corner portion 21a after the half-cutting, as described above. Figure 24 Figure 14 ​The horizontal axis of the graph shown is the press area Ar (mm 2 ) of the pad 7 used in the press process. Figure 24 The press area Ar refers to the area surrounded by the extension surface 70a of the vertical wall surface 70, the extension surface 71a of the bottom wall surface 71, and the press surface 72 when the pad 7 is observed in a cross section along the pressing direction of the corner portion 13m.

[0212] In the graph, the marks of triangles or circles labeled with "al" to "al8" indicate the height h of the corner portion 21a and the press area Ar in the present application examples 1 to 18. The marks of crosses labeled with "bl" to "b3" indicate the height h of the corner portion 21a and the press area Ar in the comparative examples 1 to 3. That is, "a" indicates the marks of the present application examples, and "b" indicates the marks of the comparative examples. The numbers of the marks correspond to the numbers of the examples.

[0213] The marks of triangles (a3, a6, alO, al l, al3, al8) in the marks of the present application examples indicate the height h of the corner portion 21a and the press area Ar after the half-cut when the height ho of the projection 13h is 0.20 mm or less and whisker burrs are generated. The marks of circles (al, a2, a4, a5, a7 to a9, al2, al4 to al7) indicate the height h of the corner portion 21a and the press area Ar after the half-cut when the height ho of the projection 13h is 0.20 mm or less and whisker burrs are not generated. The marks of crosses indicate the height h of the corner portion 21a and the press area Ar after the half-cut when the height ho of the projection 13h exceeds 0.20 mm and whisker burrs are generated.

[0214] As is clear from the graph of ​ , the height ho of the projection 13h and the generation condition of whisker burrs have a correlation with the height h of the corner portion 21a after the half-cut (before the finish-cut) and the press area Ar of the pad 7 used in the press process.

[0215] The straight line shown in the graph is an approximate straight line (h = -1.09Ar + 1.04) obtained from the test examples in which the height ho of the projection 13h is 0.20 mm or less. It is known that if the height h of the corner portion 21a after the half-cut and the press area Ar are included in a region lower than this approximate straight line, the height ho of the projection 13h can be 0.20 mm or less.

[0216] The curved line shown in the graph is an approximate curved line (h = 1.20Ar 2(-2.07Ar + 0.90). It is known that if the height h of the protrusion 21a after the half-cut and the press-fitting area Ar are included in a region lower than the approximate curve, the height ho of the protrusion 13h can be made to be 0.20 mm or less, and the occurrence of whisker-like burrs can be avoided.

[0217] Examples 1 to 14 of the Invention are examples that satisfy the formulas (al) to (a5) related to the half-cutting process and the formulas (bl) and (b2) related to the finish-cutting process.

[0218] On the other hand, Examples 15 to 17 of the Invention are examples that do not satisfy at least one of the formulas (al) to (a5) related to the half-cutting process. More specifically, Example 15 and 16 of the Invention do not satisfy the formula (a2), and Example 17 of the Invention does not satisfy the formulas (a3) and (a4).

[0219] In the processed product samples of Examples 1 to 14 of the Invention, the following target is achieved: the ratio L1 / t1 of the plated component residual length L1, in which the sheared surface 13d is covered with the plating layer 13f on the surface of the plated metal sheet, to the sheet thickness t1 of the cut end portion 13 is 0.80 or more. On the other hand, in the processed product samples of Examples 15 to 17 of the Invention, the ratio L1 / t1 is less than 0.80. From this result, it is preferable to satisfy the formulas (al) to (a5) related to the above-mentioned half-cutting process.

[0220] In addition, Example 18 of the Invention is an example that does not satisfy at least one of the formulas (bl) and (b2) related to the finish-cutting process. More specifically, Example 18 of the Invention does not satisfy the formula (bl).

[0221] In the processed product samples of Examples 1 to 14 of the Invention, the following target is achieved: the height Lc in the sheet thickness direction T from the lower surface 13b of the cut end portion 13, which is the upper end of the plating layer 13k that is wound around the lower surface 13b of the cut end portion 13, is 0.10 times or more of the curvature radius Ro or the taper height Co of the press-fitting surface 13e. On the other hand, in the processed product sample of Example 18 of the Invention, the height Lc is less than 0.10 times of the curvature radius Ro or the taper height Co. From this result, it is preferable to satisfy the formulas (bl) and (b2) related to the above-mentioned finish-cutting process.

[0222] Further, the technical solutions described in the present specification can also be described as follows.

[0223] [1] A method of manufacturing a metal work, which is manufactured using a plated metal sheet having a plated layer on a surface as a blank, has a cut end portion along a sheet thickness direction of the blank, and has a coining surface formed at a corner portion of the cut end portion, the method comprising: a half-cutting step of forming a half-cut portion by half-cutting a first blank formed of the blank in the sheet thickness direction using a first punch and a first die; a finish-cutting step of finish-cutting the half-cut portion in the same direction as the half-cutting using a second punch and a second die to obtain a second blank having the cut end portion; and a coining step of pressing the corner portion of the cut end portion of the second blank against an anvil to obtain a metal work having a coining surface formed at the corner portion, wherein, in the half-cutting step, a clearance C 31-41 (mm) between the first punch and the first die is set to be a negative clearance, a tip of the first punch and a tip of the first die are provided in an R shape having a prescribed radius of curvature R D1 , R P1 (mm), a horn portion having a height h (mm) is formed at the half-cut portion, the height h (mm) corresponds to a separation distance along a pressing direction of the first punch of a position on the tip of the first punch on an extension line of a side surface of the first punch and an extension line of an upper surface of the first punch contacting a lower surface of the first blank, and is represented by the following equation:

Mathematical Equation 4

[0224] BRIEF DESCRIPTION OF DRAWINGS

[0225] 1: metal workpiece; 2: first blank; 3: second blank; 7: pad; 13: cut end portion; 13a: upper surface; 13b: lower surface; 13c: draw; 13d: shear face; 13d1: first shear face; 13d2: second shear face; 13e: coining face; 13f: plated layer from upper surface; 13h: protruding portion; 13k: plated layer from lower surface; 13m: corner portion; 21: half-cut portion; 21a: protruding corner portion; 31: first punch; 32: second punch; 41: first punch; 42: second punch; 70: vertical wall surface; 71: bottom wall surface; 72: pressing surface.

Claims

1. A method for manufacturing a metal workpiece, comprising manufacturing a metal workpiece having a coating on its surface as a blank, having a cut-off end along the thickness direction of the blank, and having a precision-pressed surface formed at the corner of the cut-off end, the manufacturing method comprising: In the semi-cutting process, the first die and the first punch are used to cut the first blank formed from the blank in the thickness direction to form a semi-cut part; In the precision cutting process, a second die and a second punch are used to precisely cut the half-cut portion from the same direction as the half-cut portion, thereby obtaining a second blank having the cut end. as well as In the precision pressing process, the corner portion of the cut end of the second blank is pressed onto the pad to obtain a metal product with a precision-pressed surface formed at the corner portion. Regarding the aforementioned semi-cutting process The gap C between the first die and the first punch 31-41 Set to negative clearance. The cutting tip of the first die and the cutting tip of the first punch are configured to have a specified radius of curvature R. D1 R P1 The R shape, A protruding corner with a height h is formed in the semi-cut portion, the height h being equivalent to the separation distance along the pressing direction of the first punch from the position of the tip of the first punch on the extension line of the side surface of the first die to the extension line of the upper surface of the first punch that contacts the lower surface of the first blank, and expressed by the following formula: Wherein, the gap C 31-41 The radius of curvature R D1 R P1 The unit of the height h is mm. Regarding the aforementioned precision pressing process The pad has a longitudinal wall surface, a bottom wall surface, and a planar or curved pressing surface that connects the longitudinal wall surface and the bottom wall surface at the corner where they abut, and is used to press the corner portion of the cut end. When viewing the pad in a cross-section along the pressing direction of the corner, and defining the area enclosed by the extended surface of the longitudinal wall, the extended surface of the bottom wall, and the pressing surface as the fine pressing area Ar, the fine pressing area Ar is set to satisfy the following formula: h≤-1.09Ar+1.04 The unit of the precision pressing area Ar is mm. 2 .

2. The method for manufacturing metal articles according to claim 1, wherein, The fine pressing area Ar is set to further satisfy the following formula: h≤1.20Ar 2 -2.07Ar+0.90 The unit of the precision pressing area Ar is mm. 2 .

3. The method for manufacturing metal articles according to claim 1 or 2, wherein, Regarding the aforementioned semi-cutting process The gap C between the first die and the first punch 31-41 The following expression (a1) is satisfied. -0.35×t1≤C 31-41 ≤-0.0125×t1···(a1) Where t1 is the thickness of the half-cut portion of the first blank, and the unit of t1 is mm, and the gap C 31-41 The unit is mm. The radius of curvature R of the tip of the first die D1 The following expression (a2) is satisfied. 0.10×t1≤R D1 ≤1.50···(a2) Wherein, the radius of curvature R D1 The unit is mm. The radius of curvature R of the tip of the first punch P1 The following formula (a3) ​​is satisfied. 0.10×t1≤R P1 ≤3.00···(a3) Wherein, the radius of curvature R P1 The unit is mm. The pressing amount D of the first die relative to the half-cut portion satisfies the following formula (a4). 1.00×t1 <D≤t1+1.00···(a4) The unit of the pressing amount D is mm. The distance C between the first die and the first punch at the lower stop point D1-P1 The following formula (a5) is satisfied. 0.20 ≤ C D1-P1 ···(a5) Wherein, the interval C D1-P1 The unit is mm.

4. The method for manufacturing metal articles according to claim 3, wherein, Regarding the aforementioned precision cutting process The gap C between the second die and the second punch 32-42 The following formula (b1) is satisfied. 0.01≤C 32-42 ≤0.20×t2···(b1) Wherein, t2 is the thickness of the half-cut portion of the first blank, which is equivalent to the separation distance along the pressing direction of the first die from the connection position between the tip of the first die and the side surface, and the upper surface of the tip of the first punch in contact with the lower surface of the first blank, when the first die is pressed into the lower stop point. The unit of t2 is mm, and the gap C... 32-42 The unit is mm. The cutting tip of the second die is configured to have a specified radius of curvature R. D2 The R shape, The radius of curvature R of the cutting tip of the second die D2 The following formula (b2) is satisfied. 0.25 ≤ R D2 ≤1.50×t2···(b2) Wherein, the radius of curvature R D2 The unit is mm.

5. A metal workpiece, comprising a plated metal sheet having a coating on its surface as a blank, and having a cut-off end along the thickness direction of the blank. The cut-off end has, in the thickness direction of the plate, a collapsed edge, a shearing surface, and a fine pressing surface, sequentially from the upper surface side to the lower surface side. The shear surface has a first shear surface continuous with the collapsed edge and a second shear surface continuous with the first shear surface in the plate thickness direction. The inclination angle θd1 of the first shear surface with respect to the plate thickness direction and the inclination angle θd2 of the second shear surface with respect to the plate thickness direction satisfy θd1 > θd2. The ratio L1 / t1 of the residual length L1 of the plating component covering the sheared surface to the plate thickness t1 at the cut end is 0.80 or greater, wherein, The units for the residual length L1 of the plating component and the plate thickness t1 at the cut end are both mm. The ratio Z / t1 of the collapsed edge length in the plate thickness direction toward the lower surface of the cut-off end, with the upper surface of the cut-off end as a reference, to the plate thickness t1 of the cut-off end, is -0.10 or more and less than 0.10, wherein the units of the collapsed edge length Z and the plate thickness t1 of the cut-off end are both mm. A protrusion with a height h0 exceeding 0 mm and greater than 0.20 mm is provided at the lower part of the precision pressing surface. The coating on the surface extends from the lower surface of the cut end to the end face of the cut end. The height Lc of the upper end of the coating extending from the lower surface in the plate thickness direction, with the lower surface as a reference, is at least 0.10 times the radius of curvature R0 or the height C0 of the precision pressing surface. The units of the height Lc, the radius of curvature R0 of the precision pressing surface, and the height C0 of the cone surface are all mm.

Images