Processed product and method for manufacturing processed product

Abstract

A processed product which uses a plated steel sheet having a plated layer on a surface as a raw material and has a cut end portion in a sheet thickness direction of the processed product, the cut end portion has, in the sheet thickness direction of the cut end portion, in order, a curl, a sheared surface, and a fractured surface or has, in order, a curl and a sheared surface, a ratio (L / t1) of a plated component remaining length (L) with which the sheared surface is covered by the plated layer to a sheet thickness (t1) of the cut end portion of the processed product is 0.70 or greater, and a length (Z) of the curl in the sheet thickness direction of the cut end portion is a value that is 0 times and less than 0.10 times the sheet thickness (t1) of the cut end portion of the processed product.

Description

Technical Field

[0001] This invention relates to a method for manufacturing a processed article using a plated steel sheet with a coating on its surface as raw material and having a cut-off end, and to the processed article thereof. Background Technology

[0002] In recent years, there has been an increasing use of plated steel sheets as raw materials for components in automobiles, home appliances, and other equipment. Using plated steel sheets as raw materials eliminates the need for post-forming surface treatment, thereby reducing manufacturing costs. Furthermore, omitting post-forming surface treatment avoids deterioration in the dimensional accuracy of parts caused by such treatment. The omission of post-forming surface treatment is particularly being studied for components requiring high dimensional accuracy, such as motor housings.

[0003] When post-forming surface treatment is omitted, areas of exposed steel sheet substrate appear at the cut ends of the finished product. Depending on the environment in which the product is placed, red rust sometimes develops in these exposed areas. This red rust deteriorates the appearance of the product. Furthermore, the area of ​​red rust formation expands over time, raising concerns about a potential reduction in the product's strength. Particularly in the case of household appliances, there are concerns about electrical short circuits caused by rust flakes off.

[0004] Additionally, screw holes are sometimes provided in the flange portion of deep-drawn parts, such as motor housings, to secure the parts to other equipment. Poor flatness around the screw holes can lead to reduced tightening force. To ensure flatness around the screw holes, the flange size is set relatively large when the flange is cut off, taking into account the size of the burr at the cut end. However, increasing the flange size becomes a major cause of increased raw material weight.

[0005] As a method to improve the rust resistance of the cut end of the processed product, for example, Patent Document 1 proposes the following method: In Zn-plated steel sheets with a thickness of 2 mm or less, a blanking process is performed by using a die with a radius of curvature of 0.1 to 0.5 times the thickness of the Zn-plated steel sheet on the shoulder of the punch or die, so that the shearing surface ratio of the blanking end face after blanking is 90% or more, and the zinc coverage of the shearing surface is 50% or more.

[0006] In addition, Patent Document 2 proposes the following method: the blanking gap is set to 1% to 20% of the plate thickness regardless of the thickness of the Zn-based coated steel sheet, and the Zn-based coated steel sheet is cut using a die with a radius of curvature of 0.12 times or more than the thickness of the Zn-based coated steel sheet at the shoulder of the punch or die, so as to obtain a processed product with a slump Z of 0.10 × plate thickness or more and a slump X of 0.45 × plate thickness or more on the cut end face.

[0007] Furthermore, the following method is proposed in Patent Document 3: By performing semi-blanking of 60 to 95% of the plate thickness on a plated steel sheet with a negative clearance, and shearing from the opposite side of the semi-blanking with a flat press (Japanese: 平押し), a product with corrosion resistance on the end face is obtained.

[0008] In addition, Patent Document 4 discloses a stamping method for a metal sheet, which includes: a first step in which a first punch and a first die are used to give a trimming margin to the final machining surface of the blanking portion of the metal sheet and perform semi-blanking on the metal sheet; and a second step in which a second punch and a second die are used to further perform trimming mainly by shearing on the portion after semi-blanking, and ensure a shearing surface of 70% or more on the final machining surface of the blanking portion.

[0009] Furthermore, a shearing and punching method is described in Patent Document 5. In this method, after the first step is performed with a negative clearance, a second step is performed with a positive clearance using a punch and a die that do not give roundness (R) to the cutting edge tip.

[0010] Existing technical documents

[0011] Patent documents

[0012] Patent Document 1: Japanese Patent No. 5272518 Gazette

[0013] Patent Document 2: Japanese Patent No. 6073025 Gazette

[0014] Patent Document 3: Japanese Unexamined Patent Application Publication No. 2002-321021 Gazette

[0015] Patent Document 4: Japanese Unexamined Patent Application Publication No. 2004-174542 Gazette

[0016] Patent Document 5: Japanese Unexamined Patent Application Publication No. 11-254055 Gazette Summary of the Invention

[0017] The problem the invention aims to solve

[0018] However, in the method described in the above Patent Document 1, when a steel sheet with a thickness of 2 mm or less is used as the object and a steel sheet with a thickness exceeding 2 mm is used as the raw material, the zinc coverage rate of the shearing surface becomes insufficient, and it may be difficult to suppress the generation of red rust. In addition, it is also difficult to apply deep-drawn products such as motor casings that have thickening at the flange end portion.

[0019] In the method described in Patent Document 2 above, the resulting workpiece has a sag Z at the cut end that is 0.10 or more times the plate thickness and a sag X that is 0.45 or more times the plate thickness, resulting in a large sag. Therefore, the effective contact area around the screw hole is reduced, leading to a decrease in the tightening force of the fixing screw. On the other hand, if the size of the flange portion is increased to ensure the flatness around the screw hole, it becomes a major cause of increased raw material weight. Therefore, this method is sometimes unsuitable for deep-drawn workpieces such as motor housings where the flange portion is fixed.

[0020] In the method described in Patent Document 3 above, the plated steel sheet is partially punched with a negative gap, and then sheared by flat pressing from the opposite side of the partially punched section. As a result, a fracture surface is generated at the middle position in the thickness direction of the cut end of the plated steel sheet, and burrs may also be generated during flat pressing, which may degrade the shape quality.

[0021] The method described in Patent Document 4 is a technique for edge trimming, which results in a larger sheared surface and a better final processed surface for the metal sheet. However, even when trimming a metal sheet with a coating, the coating is almost completely absent from the final processed surface, thus reducing the corrosion resistance of the final processed surface.

[0022] In the method described in the aforementioned Patent Document 5, the tip of the punch and die used in the second step is not given roundness (R), so even if the plated steel sheet is used as the raw material, it is impossible to expect the effect of leaving a coating on the cut end face.

[0023] Therefore, the present invention was made in view of the above-mentioned problems, and the object of the present invention is to provide a processed article with good corrosion resistance and shape quality, and a method for manufacturing the processed article, even when using galvanized steel sheet with a thickness of more than 2.0 mm as raw material.

[0024] Solution for solving the problem

[0025] To solve the above problems, according to a certain aspect of the present invention, a processed article is provided, which uses a plated steel sheet with a coating on its surface as raw material and has a cut-off end along the thickness direction of the processed article. The cut-off end has a collapsed edge, a shear surface, and a fracture surface in sequence along the thickness direction of the cut-off end, or a collapsed edge and a shear surface in sequence. The ratio L of the residual length of the coating component covered by the coating on the shear surface to the thickness t1 of the cut-off end of the processed article, L / t1, is 0.70 or more. The length Z of the collapsed edge in the thickness direction of the cut-off end is a value that is more than 0 times and less than 0.10 times the thickness t1 of the cut-off end of the processed article.

[0026] Alternatively, the length W1 of the fracture surface in the thickness direction of the cut end exceeds 0 mm but is less than 1.0 mm.

[0027] Alternatively, the length W1 of the fracture surface in the thickness direction of the cut end is less than 0.5 mm.

[0028] Alternatively, the length X of the collapsed edge in a plane orthogonal to the thickness direction of the cut end is a value that is 0 times greater than the thickness t1 of the cut end of the workpiece and less than 0.30 times.

[0029] Alternatively, the length of the burr at the cut end can be less than 0.2 mm.

[0030] Alternatively, the cut end may have a collapsed edge, a shearing surface, a fracture surface, and a fine pressing surface in sequence along the thickness direction of the plate, or a collapsed edge, a shearing surface, and a fine pressing surface in sequence, wherein the length W2 of the fracture surface between the shearing surface and the fine pressing surface in the thickness direction of the cut end exceeds 0 mm and is less than 0.5 mm.

[0031] In addition, to solve the above-mentioned problems, according to another aspect of the present invention, a method for manufacturing a processed article is provided, which is used to manufacture a processed article having a cut-off end on a plated steel sheet with a coating on its surface as raw material. The method includes: a partial cutting step, in which a first die and a first punch with a negative clearance are used to partially cut a cut portion of a first blank formed from the raw material along the thickness direction; and a fine cutting step, in which a second die and a second punch are used to finely cut the partially cut first blank from the same direction as the partial cutting step, to obtain a processed article having a cut-off end along the thickness direction. When the cut-off end is formed on the outer periphery of the processed article, the inner diameter D of the second die... 32 Let D be the inner diameter of the first die. 31 In the case where a cut-off end is formed on the inner side of the workpiece, the outer diameter d of the second die is as follows: 32 Let d be the outer diameter of the first die. 31 Hereinafter, the thickness of the cut portion of the first blank is defined as t1, and the residual thickness of the cut portion after the semi-cutting process is defined as t2. In the semi-cutting process, the gap C between the first die and the first punch is defined as... 31-41 The following equation (a1) is satisfied, the radius of curvature R1 of the cutting tip of the first die satisfies the following equation (a2), the pressing amount D of the first die or the first punch relative to the cut portion of the first blank satisfies the following equation (a3), and the interval C between the first die and the first punch at the lower dead center is satisfied. P-D The clearance C between the second die and the second punch in the precision cutting process satisfies the following formula (a4). 32-42The radius of curvature R2 of the cutting edge of the second die satisfies the following equation (a5), and the radius of curvature R2 of the cutting edge satisfies the following equation (a6):

[0032] -0.25×t1≤C 31-41 ≤-0.01…(a1)

[0033] 0.10×t1≤R1≤0.50×t1…(a2)

[0034] D≥0.70×t1…(a3)

[0035] C P-D ≥0.20…(a4)

[0036] 0.01≤C 32-42 ≤0.2×t2…(a5)

[0037] 0.25≤R2≤1.50×t2…(a6),

[0038] Here, C 31-41 C P-D C 32-42 And the unit of R2 is mm.

[0039] Furthermore, to solve the above-mentioned problems, according to another aspect of the present invention, a method for manufacturing a processed article is provided, which is used to manufacture a processed article having a cut-off end on a plated steel sheet with a coating on its surface as raw material. The method includes: a semi-cutting step, in which a first die and a first punch with a negative clearance are used to semi-cut a cut portion of a first blank formed from the raw material along the thickness direction; and a fine cutting step, in which a second die and a second punch are used to finely cut the semi-cut first blank from the same direction as the semi-cutting step, obtaining a processed article having a cut-off end with a cut surface along the thickness direction. When the cut-off end is formed on the outer periphery of the processed article, the inner diameter D of the second die... 32 Let D be the inner diameter of the first die. 31 In the case where a cut-off end is formed on the inner side of the workpiece, the outer diameter d of the second die is as follows: 32 Let d be the outer diameter of the first die. 31 Hereinafter, the thickness of the cut portion of the first blank is defined as t1, and the residual thickness of the cut portion after the semi-cutting process is defined as t2. In the semi-cutting process, the gap C between the first die and the first punch is defined as... 31-41The radius of curvature R11 of the tip of the first die satisfies the following equation (b1), the radius of curvature R12 of the tip of the first punch satisfies the following equation (b2-2), the pressing amount D of the first die or the first punch relative to the cut portion of the first blank satisfies the following equation (b3), and the distance C between the first die and the first punch at the lower dead center is satisfied. P-D The clearance C between the second die and the second punch in the precision cutting process satisfies the following formula (b4). 32-42 The radius of curvature R2 of the cutting edge of the second die satisfies the following equation (b5), and the following equation (b6) also satisfies the following equation:

[0040] -0.35×t1≤C 31-41 ≤-0.10×t1…(b1)

[0041] 0.10×t1≤R11≤0.65×t1…(b2-1)

[0042] 0.10×t1≤R12≤0.65×t1…(b2-2)

[0043] D≥0.70×t1…(b3)

[0044] C P-D ≥0.20…(b4)

[0045] 0.01≤C 32-42 ≤0.2×t2…(b5)

[0046] 0.25≤R2≤1.50×t2…(b6),

[0047] Here, C 31-41 C P-D C 32-42 And the unit of R2 is mm.

[0048] Alternatively, the above-mentioned processing method may also include a precision pressing process, in which the processed product obtained in the precision cutting process is used as the second blank, and the corner of the cut end of the second blank is pressed against the pad to obtain a processed product with a precision pressing surface formed at the corner.

[0049] Alternatively, if a cut-off end is formed on the outer periphery of the workpiece, the inner diameter D of the first die can be... 31 With the inner diameter D of the second die 32 The absolute value of the difference |D 32 -D 31 |When the diameter is set to 1.00mm or less, and a cut-off end is formed on the inner side of the workpiece, the outer diameter d of the first die is... 31 With the outer diameter d of the second die 32 The absolute value of the difference |d 32 -d31 | Set to below 1.00mm.

[0050] Alternatively, the above-mentioned processing method may also include a preparation step before the semi-cutting step, in which a first blank having hollow sidewalls and flanges is formed from a flat plated steel sheet.

[0051] The effects of the invention

[0052] As explained above, according to the present invention, even when using galvanized steel sheets with a thickness exceeding 2.0 mm as raw materials, it is possible to obtain processed products with good corrosion resistance and shape quality. Attached Figure Description

[0053] Figure 1 This is a perspective view showing an example of a processed article manufactured using the processed article manufacturing method according to the first embodiment of the present invention.

[0054] Figure 2 It means Figure 1 The diagram shows the cut-off end 13 of region A of the workpiece 1. The left side is a cross-sectional view at the ZX plane containing the central axis of the workpiece, and the right side is a view viewed from the X direction.

[0055] Figure 3 yes Figure 2 Detailed view of the sectional view on the left.

[0056] Figure 4 It means Figure 3 A graph showing the relationship between collapsed edge X and collapsed edge Z.

[0057] Figure 5 This is an explanatory diagram illustrating the method for manufacturing processed articles according to this embodiment.

[0058] Figure 6 This is an explanatory diagram showing a semi-cutting process where the tip of the die used in the semi-cutting process is set to an arc shape.

[0059] Figure 7 It means to continue Figure 6 The diagram illustrates the fine cutting process performed during the semi-cutting process.

[0060] Figure 8 This is an explanatory diagram showing a semi-cutting process where the cutting tips of the die and punch used in the semi-cutting process are set to an arc shape.

[0061] Figure 9 It means to continue Figure 8 The diagram illustrates the fine cutting process performed during the semi-cutting process.

[0062] Figure 10 This is an explanatory diagram showing how the location of the screw hole varies depending on the size of the collapsed edge X in the planar direction.

[0063] Figure 11 This is an explanatory diagram illustrating a method for manufacturing a processed article according to the second embodiment of the present invention.

[0064] Figure 12 This is an explanatory diagram showing the precision pressing process.

[0065] Figure 13 The diagram shows the cut end of the workpiece after the precision pressing process. The left side is a cross-sectional view at the ZX plane containing the central axis of the workpiece, and the right side is a side view from the X direction.

[0066] Figure 14 This is a photograph showing an example of the cut end of a finished product after the precision pressing process.

[0067] Figure 15 This is an explanatory diagram showing the volume of the corner that is flattened by the pad during the precision pressing process.

[0068] Figure 16 This is a three-dimensional diagram representing an example of a processed product.

[0069] Figure 17 This is a three-dimensional diagram representing another example of a processed product.

[0070] Figure 18 This is a three-dimensional diagram representing another example of a processed product.

[0071] Figure 19 This is a three-dimensional diagram representing another example of a processed product.

[0072] Figure 20 This is a schematic diagram showing an example of a cutting die used to process flat washers.

[0073] Figure 21 It means to utilize Figure 20 A schematic diagram showing the state of a cutting die punching raw materials.

[0074] Figure 22 This is a three-dimensional diagram representing another example of a processed product. Detailed Implementation

[0075] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Furthermore, in this specification and the drawings, redundant descriptions are omitted by using the same reference numerals to denote structural elements having substantially the same functional structure.

[0076] [1. First Embodiment]

[0077] [1-1. Processed Products]

[0078] First, based on Figure 1 The processed article 1 manufactured using the processed article manufacturing method of the first embodiment of the present invention will be described. Figure 1 This is a perspective view showing an example of a processed article 1 manufactured using the processed article manufacturing method according to the first embodiment of the present invention. Figure 1 The processed product 1 shown is a motor housing made of plated steel sheet with a coating on its surface. Figure 1 The motor housing shown can be formed by forming processes such as deep drawing on a flat plated steel sheet.

[0079] like Figure 1 As shown, the processed article 1 of this embodiment has a main body 10, a protrusion 11, and a flange 12.

[0080] The main body 10 has a hollow cylindrical side wall 101 and a top wall 103 formed to cover one end of the side wall 101. The top wall 103 is sometimes referred to as a bottom wall or other names depending on the orientation of the workpiece 1. Figure 1 The cross-sectional shape of the main body 10 of the processed article 1 shown in the XY plane is a perfect circle, but the present invention is not limited to this example. The cross-sectional shape of the main body 10 in the XY plane may also be other shapes such as ellipse or polygon.

[0081] The protrusion 11 is a protrusion that extends from the top wall 103 toward the outer side of the central axis (Z direction) of the main body 10. In addition, the protrusion 11 is not necessarily required, and the top wall 103 can also be flat.

[0082] The flange portion 12 is a plate portion extending radially outward from the end of the main body portion 10 (i.e., the other end of the sidewall 101). The shape of the flange portion 12 is arbitrary. In this embodiment, the flange portion 12 extends radially along the entire circumferential region of the main body portion 10. A plurality of screw holes 121 are provided in the flange portion 12, spaced apart from each other in the circumferential direction of the main body portion 10. Screws 123 pass through the screw holes 121. The workpiece 1 can be fixed to a mounting object, such as a vehicle body, by using screws 123.

[0083] In this embodiment, the flange portion 12 is a flange portion blank having an outer diameter larger than the outer diameter of the flange portion 12 ultimately formed on the workpiece 1. Figure 5 The flange blank 20 is formed by cutting. That is, the processed product 1 of this embodiment has a cut end 13 on the outer periphery of the flange 12.

[0084] Cutting processes include shearing, punching, and opening. Shearing is the process of cutting an object along a predetermined straight line or curve. Punching is the process of punching out a product from the sheared object. Opening is the process of punching out a non-product portion from the sheared object to obtain a product with an opening. Figure 1 The flange portion 12 shown can be obtained by punching from the flange portion blank.

[0085] As the coated steel sheet, coated steel sheets with various coatings are preferred. Various steel sheets can be used as the coated steel sheet, but Zn-based coated steel sheets are preferred. Zn-based coatings include Zn plating, Zn-Al alloy plating, Zn-Al-Mg alloy plating, and Zn-Al-Mg-Si alloy plating. Steel sheets coated with Zn-Al-Mg alloys are particularly preferred. Here, the alloy plating preferably contains 80% by mass or more Zn relative to the total molar number of the plating, and more preferably 90% by mass or more Zn.

[0086] The base steel sheet for galvanized steel sheets can be any type of steel, but it can be, for example, very low carbon steel.

[0087] The amount of plating adhering to the plated steel sheet can also be preferably 30 g / m². 2 The lower limit is preferred, and 45g / m 2 This is the lower limit. Additionally, the coating adhesion amount on the galvanized steel sheet can preferably be 450 g / m². 2 The upper limit is preferred, and more preferably 190g / m 2 This is the upper limit. Specifically, by achieving a plating adhesion amount of 45 g / m². 2 The above makes it easy for the plated metal to wrap around the shear surface of the cut end 13. Figure 2 The shear surface 13c is thus able to improve the corrosion resistance after cutting.

[0088] The thickness of the galvanized steel sheet (the thickness of the base steel sheet + the thickness of the coating) is arbitrary, but it can be less than 2.0 mm or more than 2.0 mm. For example, the thickness of the galvanized steel sheet can be 0.8 mm or more and 6.0 mm or less, more preferably 2.0 mm or more and 4.5 mm or less.

[0089] [1-2. Cut-off ends of the processed product]

[0090] Next, based on Figures 2-4 The cut-off end 13 of the processed product 1 of this embodiment will be described. Figure 2 Indicates that the cut end 13 is at Figure 1 The left side of the processed work 1 is a cross-sectional view of the ZX plane containing the central axis of the processed work 1, and the right side is a side view from the X direction. Figure 3 yes Figure 2Detailed view of the sectional view on the left. Figure 4 It means Figure 3 A graph showing the relationship between collapsed edge X and collapsed edge Z. Furthermore, in Figure 2 and Figure 3 In the middle, the thickness direction T of the flange portion 12 is set to be parallel to the thickness direction of the flange portion 12 Figure 1 The direction of the central axis of the processed workpiece 1 shown is the same as the Z-direction. Additionally, in Figure 2 The description of coating 13f is omitted.

[0091] For example, such as Figure 2 and Figure 3 As shown, the cut-off end 13 of the flange portion 12 of the processed article 1 has, in the thickness direction T of the flange portion 12, a collapsed edge 13b, a shear surface 13c, a fracture surface 13d, and a burr 13e sequentially from the upper surface 13a. Furthermore, it is preferable that the processed article 1 is free of burrs 13e, and the processed article 1 in this embodiment may also be a processed article 1 without burrs 13e.

[0092] The upper surface 13a is the surface into which the cutting die is pressed during the cutting process of the flange blank (the pressed surface).

[0093] The collapsed edge 13b is the portion of the flange blank (plated steel sheet) whose surface is deformed due to the tensile force acting on its surface when it is pressed into the cutting die relative to the flange blank. In this specification, the dimension of the collapsed edge 13b in the thickness direction T of the flange portion 12 is referred to as "collapsed edge Z", and the dimension of the collapsed edge 13b in the plane direction orthogonal to the thickness direction T is referred to as "collapsed edge X".

[0094] The shearing surface 13c is formed by shearing the flange blank by the tip of the cutting die. The shearing surface 13c is adjacent to the collapsed edge 13b in the thickness direction T of the flange 12.

[0095] The fracture surface 13d is formed by the convergence of cracks generated in the blank at the flange portion from the tip of the cutting die. The fracture surface 13d is adjacent to the shear surface 13c in the thickness direction T of the flange portion 12.

[0096] Burr 13e is the portion of the flange blank that is stretched or torn during the formation of fracture surface 13d. Burr 13e is adjacent to fracture surface 13d in the thickness direction T of flange portion 12.

[0097] As will be explained later, by cutting the flange blank 20 using the workpiece manufacturing method of this embodiment, the collapsed edge 13b, fracture surface 13d, and burr 13e can be minimized.

[0098] like Figure 3As shown, in the processing method of this embodiment, the cut-off end 13 is formed such that a plating layer 13f wraps around the upper surface 13a of the cut-off end 13 to the shearing surface 13c. When the cutting tip of the cutting die cuts into the flange blank, the plating layer 13f is stretched by the cutting die and wrapped around the shearing surface 13c. Through the wrapping of the plating layer 13f, at least a portion of the shearing surface 13c is covered by the plating layer 13f. In the portion of the shearing surface 13c covered by the plating layer 13f, the formation of red rust can be suppressed. In addition, when the plating layer 13f is a Zn-based plating layer, due to the alternative corrosion protection effect of the Zn-based plating layer, the formation of red rust can be suppressed even in the vicinity of the portion covered by the plating layer 13f.

[0099] At this time, in the processed product 1, the length L of the plating layer 13f covering at least a portion of the collapsed edge 13b and the sheared surface 13c from the upper surface 13a of the cut end 13 is at least 0.7 times the plate thickness t1 of the cut end 13 of the processed product 1. That is, the ratio L of the residual length of the plating component covered by the plating layer 13f on the sheared surface 13c to the plate thickness t1 of the cut end 13 of the processed product 1, L / t1, is at least 0.70. The length L of the plating layer 13f can also be described as the distance between the upper surface 13a of the cut end 13 and the lower end of the plating layer 13f in the plate thickness direction T of the flange portion 12. In addition, as Figure 2 As shown, the plate thickness t1 of the cut end 13 of the processed product 1 is equal to the plate thickness of the flange portion 12 of the processed product 1. Therefore, the plate thickness of the flange portion 12 will sometimes be referred to as "plate thickness t1" below.

[0100] The fracture surface 13d is formed as a result of the fusion of cracks generated in the flange blank, and is a rough, newly formed surface. At the fracture surface 13d, the metallic composition of the steel substrate is exposed. The plating 13f covering the shear surface 13c is difficult to penetrate into the fracture surface 13d. Therefore, the fracture surface 13d is more prone to developing red rust than other surfaces of the cut end 13.

[0101] The inventors of this application conducted experiments varying the plate thickness t1 of the flange portion 12 with the cut-off end 13, the cutting conditions, and the surface treatment conditions within various ranges, and investigated the formation of red rust. The results showed that when cutting a plated steel sheet, the plating layer 13f is wound from the upper surface 13a to the shear surface 13c, resulting in a workpiece 1 with a ratio L / t1 of 0.70 or higher and a length (collapse edge Z) of the collapsed edge 13b in the plate thickness direction T of the flange portion 12 exceeding 0 times and less than 0.10 times the plate thickness of the flange portion 12 (i.e., the plate thickness t1 of the cut-off end 13 of the workpiece 1). It was found that with this cutting process, it is not necessary to additionally increase the blank size to ensure the flatness of the periphery of the screw 123 required for fixing the workpiece 1, and the formation of red rust at the cut-off end 13 over time after the cutting process can be suppressed.

[0102] Here, the plate thickness of the flange portion 12 is equal to the plate thickness t1 of the cut end 13 of the workpiece 1, and is set as the outermost plate thickness of the flange portion 12 (wherein it is set as the plate thickness of the portion where no collapse edge 13b occurs). It is preferable that the length of the fracture surface 13d in the plate thickness direction T of the flange portion 12 (hereinafter also referred to as the "fracture surface length") W1 is greater than 0 mm and less than 1.0 mm. If the fracture surface length W1 is set to less than 1.0 mm, even if red rust forms on the fracture surface 13d, it will not be noticeable, and therefore it can be determined that it will not cause problems in practical use. The fracture surface length W1 of the workpiece 1 is preferably small, and can also be set to less than 0.8 mm or less or less than 0.6 mm. It is even more preferable that the fracture surface length W1 of the workpiece 1 is less than 0.5 mm, less than 0.3 mm, or less than 0.2 mm. Alternatively, the ratio W1 / t1 of the fracture surface length W1 to the plate thickness t1 of the cut end 13 of the workpiece 1 can be set to less than 0.15, less than 0.10, less than 0.08, less than 0.06, or less than 0.04. Furthermore, the fracture surface length W1 of the workpiece 1 can also be 0 mm. That is, it is also possible that there is no fracture surface 13d at the cut end 13 of the workpiece 1. In this case, the cut end 13 has a collapsed edge 13b and a shear surface 13c sequentially from the upper surface 13a in the plate thickness direction T of the flange portion 12 (and also a burr 13e if a burr 13e is generated).

[0103] Furthermore, to ensure a flat periphery of the screw 123, it is desirable to minimize the camber edge X. The camber edge Z is related to the camber edge X. Therefore, if the easily measurable camber edge Z is adjusted, it is preferable to set the camber edge Z to be less than 0.10 times the plate thickness t1 of the flange portion 12, i.e., the cut-off end 13 of the processed product 1. Furthermore, the plate thickness t1 of the flange portion 12 is also equal to the plate thickness of the flange portion blank 20. The camber edge Z is preferably small, and can be set to be less than 0.08 times, 0.06 times, or 0.04 times the plate thickness t1 of the flange portion 12, i.e., the cut-off end 13 of the processed product 1.

[0104] exist Figure 4 The image shows an example of the relationship between the slump Z and slump X at the cut end of a product manufactured by punching in a single process. Figure 4 This indicates the relationship between the camber edge Z and camber edge X at the cut end of the product when the cutting die tip of the cutting die, pressed into the flange blank, is given a radius of curvature of 0.01 to 0.30 times the thickness of the flange blank, and the gap of the cutting die is set to 0.01 to 0.20 times the thickness of the blank. Figure 4As shown, if the blanking process is performed in a single operation, the sag X in the planar direction is approximately 3 to 4 times larger than the sag Z in the thickness direction. That is, if the blanking process is performed in a single operation, the sag X in the planar direction becomes larger. To ensure the flatness of the periphery of the screw 123 required to fix the workpiece 1 to the mounting object, the trimming dimension must be increased by the amount of sag X. Therefore, it is preferable that the sag X is greater than 0 times and less than 0.30 times the thickness t1 of the flange portion 12 of the workpiece 1, i.e., the thickness t1 of the cut end 13 of the workpiece 1. The sag X is preferably smaller, and can be set to less than 0.25 times, 0.26 times, 0.15 times, 0.12 times, or 0.10 times the thickness t1 of the flange portion 12, i.e., the thickness t1 of the cut end 13 of the workpiece 1.

[0105] Furthermore, the length of the burr 13e generated on the lower side of the fracture surface 13d at the cut end 13 of the workpiece 1 can also be set to be less than 0.2 mm. Burrs 13e can cause scratches, electrical short circuits, etc. By setting the length of the burr 13e to less than 0.2 mm, the generation of scratches, electrical short circuits, etc., can be suppressed as much as possible by preventing burrs from remaining on the workpiece 1. The length of the burr 13e is more preferably less than 0.1 mm. A burr length of 0 mm is most preferred, meaning that it is most preferred that there are no burrs 13e on the workpiece 1.

[0106] Therefore, in the processing method of this embodiment, the plated steel sheet is cut in two steps, a semi-cutting step and a fine cutting step, instead of a single cutting process. This suppresses the enlargement of the collapsed edge 13b at the cut end 13, while allowing more plating layer 13f to wrap around the shear surface 13c. The processing method of this embodiment will be described below.

[0107] [1-3. Methods for manufacturing processed products]

[0108] First, based on Figure 5 The method for manufacturing processed articles according to this embodiment will be described. Figure 5 This is an explanatory diagram illustrating the method for manufacturing a processed article according to this embodiment. (As shown...) Figure 5 As shown, the processing method of this embodiment includes a preparation process, a semi-cutting process, and a precision cutting process.

[0109] The preparation process includes preparing the first blank 2. The first blank 2 can be obtained by performing forming processes such as deep drawing on a flat plated steel sheet. That is, the first blank 2 uses plated steel sheet as raw material, just like the finished product 1. The first blank 2 has a flange blank 20, which has a larger diameter than the workpiece 1. Figure 1The flange portion 12 shown has a large outer diameter. The flange portion blank 20 can be circular or non-circular when viewed from above. For the portion other than the flange portion blank 20, the first blank 2 can have the same shape as the processed product 1. Furthermore, the preparation process is not an indispensable part of the implementation of this invention. If a blank processed by a third party using a certain method can be obtained, the preparation process can be omitted.

[0110] The semi-cutting process is a process of partially cutting the first blank 2. In the semi-cutting process, the flange blank 20 is partially cut. Semi-cutting refers to the process of cutting the flange blank 20 to a mid-section in the thickness direction of the flange blank 20. When the flange blank 20 of the first blank 2 is partially cut, the removal portion 20a that will ultimately detach from the product is separated from the flange blank 20 to the mid-section.

[0111] The precision cutting process is a process of precisely cutting the first blank 2. In the precision cutting process, the removal portion 20a of the flange blank 20 is cut off, and the flange blank 20 is separated. By cutting off the removal portion 20a, the flange portion 12 is formed. That is, in the processed article manufacturing method of this embodiment, the processed article 1 is obtained from the first blank 2 prepared in the preparation process through the semi-cutting process and the precision cutting process. Figure 1 The screw hole 121 of the processed part 1 shown can be formed in the flange blank 20 in the first blank 2 stage, or it can be formed in the flange 12 after the precision cutting process.

[0112] In the semi-cutting and fine-cutting processes of the machining method of this embodiment, a die and a punch are used to process the flange blank 20. Hereinafter, details of the semi-cutting and fine-cutting processes will be explained in two ways corresponding to the shapes of the cutting tips of the die and punch used in the semi-cutting process. Sometimes, the cutting tips of the die and punch are referred to as "shoulders".

[0113] Furthermore, in the following description, for the mold used to obtain the processed product 1, for convenience, the mold on the pressing side is referred to as a punch, and the mold on the pressing-in side is referred to as a punch. The pressing-in side mold can be located either above or below the blank. When moving in the horizontal direction, the pressing-in side mold is also referred to as a punch, and the mold on the pressing-in side is referred to as a punch. For example, Figure 2 The processed product 1 shown is a product cut by using the upper mold as the press-in side mold. When the lower mold is used as the press-in side mold, that is, when the lower mold is used as a punch, the cut end 13 of the processed product 1 and... Figure 2Conversely, the collapsed edge 13b is located at the bottom of the cut end 13, above which are the shearing surface 13c, the fracture surface 13d, and the burr 13e in sequence. Therefore, the burr 13e is located at the top. That is to say, the die that presses the surface of the finished product 1 on the side where the collapsed edge 13b is located, one of the two opposing surfaces of the flange blank 20 in the thickness direction, is called a punch, and the die that presses the surface on the side where the burr 13e is located is called a punch.

[0114] If it is unclear which mold is the upper / lower (or left / right) die or the punch, simply observe the cut end 13 based on the actual cutting, and call the mold on the side where the collapsed edge 13b is located the die, and call the mold on the side where the burr 13e is located the punch.

[0115] like Figure 2 As shown, when the cut-off end 13 is formed on the outer periphery of the workpiece 1, the die is located on the outer periphery of the punch. During processing, the inner surface of the die faces the cut-off end 13, and the outer surface of the punch is coplanar with the cut-off end 13. On the other hand, in cases such as those described later... Figure 16 In the case where the inner circumferential surface of the flat washer 900 is cut off, and a cut-off end 13 is formed on the inner circumferential side of the workpiece 1, the die is located on the inner circumferential side of the punch. During processing, the outer surface of the die faces the cut-off end 13, and the inner surface of the punch is coplanar with the cut-off end 13. Moreover, as described later... Figure 20 and Figure 21 As shown, in the case where the outer and inner peripheral sides of the workpiece 1 are cut off simultaneously, in this embodiment, the mold 61 and mold 63 on the pressing side are collectively referred to as punches, and the mold 65 on the pressing side is referred to as a punch.

[0116] (a. The case where the tip of the die used in the semi-cutting process is set to an arc shape)

[0117] First, based on Figure 6 and Figure 7 The semi-cutting and fine-cutting processes are explained when the tip of the die used in the semi-cutting process is set to an arc shape. Figure 6 This is an explanatory diagram showing a semi-cutting process where the tip of the die used in the semi-cutting process is set to an arc shape. Figure 7 It means to continue Figure 6 A diagram illustrating the fine cutting process performed during the semi-cutting process.

[0118] (Semi-cutting process)

[0119] In the semi-cutting process, such as Figure 6 As shown, the flange portion of the first blank 20 is partially cut off using the first die 31 and the first punch 41. Figure 6In this embodiment, as a method of partial cutting, a flange portion 12 is partially punched from a flange portion blank 20 held by a first punch 41 and a first pressure plate 51. The first die 31 constitutes a cutting die pressed into the flange portion blank 20 during partial cutting. In this embodiment, the die that presses the portion of the flange portion blank 20 that becomes the flange portion 12 is referred to as the first punch 41, and the die that presses and removes the portion 20a is referred to as the first die 31.

[0120] The gap C between the first die 31 and the first punch 41 31-41 Set as a negative gap. Here, gap C 31-41 This indicates the gap between the first die 31 and the first punch 41, specifically, as shown in the figure. Figure 6 As shown, the distance is represented by the distance between the side surface 31a of the first die 31 and the side surface 41a of the first punch 41. This is in the case of a state with no clearance (i.e., C...). 31-41 Using zero as a reference, and viewed from the pressing direction of the first die 31 (i.e., the thickness direction of the flange portion 12, the Z direction), the gap between the first die 31 and the first punch 41 when they are separated is called the positive gap, and the gap between the first die 31 and the first punch 41 when they are partially overlapped is called the negative gap. In this specification, the gap between the die and the punch is represented by a positive value for positive gap and by a negative value for negative gap.

[0121] like Figure 6 As shown, the first die 31 and the first punch 41, which cut the first blank 2 in half, are arranged in a manner that partially overlaps when viewed from the pressing direction of the first die 31. If the gap C... 31-41 If the clearance is set to positive, the cracks generated from the tips of the first die 31 and the first punch 41 will converge, similar to a single-pass blanking process, and the removed portion 20a may be completely cut off from the flange blank 20. Additionally, the burr 13b at the cut-off end 13 increases. By adjusting the clearance C... 31-41 Setting the gap to negative can prevent the portion 20a to be completely cut off from the flange blank 20 during the semi-cutting process, thus reducing the collapse edge 13b.

[0122] In addition, by using gap C 31-41By setting a negative clearance, a large hydrostatic pressure stress is generated in the area clamped by the first die 31 and the first punch 41. Therefore, the proportion of tensile stress generated between the material that becomes scrap after cutting (i.e., the removed portion 20a) and the flange material that becomes the flange portion 12 is reduced in the stress generated when the first die 31 is pressed into the flange blank 20. As a result, the material that becomes scrap after cutting and contacts the tip of the first die 31 tends to flow from the tip of the first die 31 towards the side 31a of the first die 31, increasing the penetration of the plating 13f into the shear surface 13c. Furthermore, due to the reduction in the proportion of tensile stress, the compressive stress increases, and the material that would normally flow towards the scrap side is pushed back towards the flange portion 12. As a result, the portion that becomes the collapsed edge 13b after cutting is also filled with material, reducing the collapse edge 13b.

[0123] In the adjacent direction between the first die 31 and the first punch 41 (in Figure 6 In 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 perform partial cutting by arranging the first die 31 such that the distance between the side 31a of the first die 31 and the end of the flange blank 20 is less than twice the thickness of the flange blank 20 (i.e., flange 12).

[0124] The gap C between the first die 31 and the first punch 41 31-41 [mm] is set to -0.01mm or less and to be more than -0.25 times the plate thickness t1[mm] of the flange portion blank 20 (i.e., flange portion 12) of the first blank 2, as shown in the following formula (a1).

[0125] -0.25×t1≤C 31-41 ≤-0.01…(a1)

[0126] If the gap C 31-41 If the clearance is below -0.01mm, it will not partially become a positive clearance due to the sliding accuracy of the punch press, the eccentricity of the die, etc., and can maintain a negative clearance. As a result, cracks will not occur during the partial cutting process, preventing complete cutting, and a large fracture surface will not be produced. On the other hand, if the clearance C... 31-41 If the thickness of the flange blank 20 is more than -0.25 times the thickness 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 smaller, which can suppress the reduction of die life. Clearance C 31-41 The upper limit can be set to -0.05 or -0.10 times the plate thickness t1 of the flange blank 20. Gap C 31-41The upper limit can also be set to -0.20 times or -0.15 times the plate thickness t1 of the flange blank 20.

[0127] like Figure 6 As shown, the tip of the first die 31 is designed as an arc shape with a radius of curvature R1. Figure 6 As shown, the first die 31 is pressed into the flange blank 20, so the tip of the first die 31 is set to an arc shape with a radius of curvature R1.

[0128] The radius of curvature R1 [mm] is, as shown in the following formula (a2), set to be more than 0.10 times and less than 0.50 times the plate thickness t1 [mm] of the flange portion blank 20 (i.e., flange portion 12) of the first blank 2.

[0129] 0.1×t1≤R1≤0.5×t1…(a2)

[0130] If the radius of curvature R1 is 0.10 times or more of the plate thickness t1, a large hydrostatic pressure is generated under negative clearance without removing the plating 13f. This allows the material that becomes scrap directly below the first die 31 and is in contact with the tip of the first die 31 to flow from the tip of the first die 31 towards the side 31a of the first die 31. This flow reduces the proportion of tensile stress generated between the material that becomes scrap after cutting (i.e., the removed portion 20a) and the flange material that becomes the flange portion 12 in the stress generated when the first die 31 is pressed into the flange blank 20. As a result, the plating 13f can be wrapped around the shear surface 13c. On the other hand, if the radius of curvature R1 is set to 0.50 times or less of the plate thickness t1, less material is located at the tip of the first die 31 during partial cutting, which reduces the formation of the fracture surface 13d in the subsequent fine cutting.

[0131] In addition, such as Figure 6 As shown, the tip of the first punch 41 is a square without roundness. In this case, the tip of the first punch 41 can also have a radius of curvature smaller than 0.1 times the thickness t1 of the flange portion of the first blank 20. The radius of curvature of the tip of the first punch 41 can also be set to be smaller than 0.06 times, 0.04 times, or 0.02 times the thickness t1 of the flange portion of the first blank 20, as needed.

[0132] The pressing amount D [mm] of the first die 31 into the flange portion blank 20 of the first blank 2 is set to at least 0.70 times the plate thickness t1 [mm] of the flange portion blank 20 (i.e., flange portion 12) of the first blank 2, as shown in the following formula (a3). Figure 6As shown, the pressing amount D is the movement of the first die 31 from the position where the first die 31 contacts the upper surface of the flange portion of the first blank 20 to the position where the pressing of the first die 31 stops (hereinafter, this position will also be referred to as the "bottom dead center"). Additionally, the distance C between the first die 31 and the first punch 41 at the bottom dead center is... P-D [mm] is set to 0.20 mm or more as shown in formula (a4) below.

[0133] D≥0.70×t1…(a3)

[0134] C P-D ≥0.20…(a4)

[0135] The residual plate thickness t2 of the flange blank 20 (i.e., the removed portion 20a) remaining in the first blank 2 after partial cutting can also be set to 0.30 times or less of the plate thickness t1 [mm] of the flange blank 20. Here, the residual plate thickness t2 refers to the residual plate thickness at the face of the cut end 13 of the processed product 1 (this face is the face opposite to the inner circumferential face of the first die 31). If the pressing amount D is more than 0.70 times the plate thickness t1, it is not easy to generate the fracture surface 13d in the subsequent fine cutting. On the other hand, by adjusting the interval C between the first die 31 and the first punch 41 at the lower stop point... P-D Ensuring a cut width of 0.20mm or more prevents cracking during partial cutting, thus avoiding localized complete cutting. Additionally, it reduces the load on the mold, suppressing mold life reduction. Furthermore, the interval C... P-D Let it be the minimum value of the interval between the first die 31 and the first punch 41 at the lower dead center.

[0136] Furthermore, the amount of pressing D [mm] of the first die 31 into the flange portion blank 20 (i.e., flange portion 12) of the first blank 2 is as shown in the above formula (a3). It can be more than 0.70 times the plate thickness t1 of the flange portion blank 20 (i.e., flange portion 12) of the first blank 2, but it can also be set to less than 0.95 times (0.70×t1≤D≤0.95×t1).

[0137] The residual plate thickness t2 is obtained by subtracting the amount of pressing D from the first die 31 into the flange blank 20 (i.e., flange 12) from the plate thickness t1, and then adding the radius of curvature R1 (t2 = t1 - D + R1). Therefore, the residual plate thickness t2 and the distance C between the first die 31 and the first punch 41 at the bottom dead center are also considered. P-DThe difference lies in the amount of material pressed into the die. If the pressing amount D is more than 0.70 times the plate thickness t1, a fracture surface 13d is less likely to be generated during the subsequent precision cutting. On the other hand, if the pressing amount D is less than 0.95 times the plate thickness t1, cracks will not be generated during the semi-cutting process due to the sliding accuracy of the punch press, the eccentricity of the die, etc., thus preventing complete cutting and the generation of a large fracture surface.

[0138] (Precision cutting process)

[0139] In the precision cutting process, such as Figure 7 As shown, the second die 32 and the second punch 42 are used to perform a precision cut on the partially cut flange blank 20. Figure 7 In this embodiment, as a method of precision cutting, a flange portion 12 is shown to be precision punched from a flange portion blank 20 held by a second punch 42 and a second pressure plate 52. The second die 32 constitutes a cutting die that is pressed into the flange portion blank 20 during precision cutting. In this embodiment, the die that presses the portion of the flange portion blank 20 that becomes the flange portion 12 is used as the second punch 42, and the die that presses down the portion 20a to be removed is used as the second die 32. The second die 32 may also be the same as the first die 31. That is, the first die 31 used in the semi-cutting process may also be used as the second die 32 in the precision cutting process.

[0140] The positional relationship between the second die 32 and the first blank 2 is preferably the same as that between the first die 31 and the first blank 2. If their positional relationships are different, for example, when the diameter of the second die 32 is larger than the diameter of the first die 31, a step difference is generated at the cut-off end 13. Conversely, for example, when the diameter of the second die 32 is smaller than the diameter of the first die 31, the second die 32 contacts the cut-off end formed in the half-cutting process, raising concerns that the second die 32 might remove the plating 13f wrapped around the shear surface 13c.

[0141] In this embodiment, the fine cut is performed in the same direction as the partial cut. That is, as... Figure 6 As shown, during the semi-cutting process, when the first die 31 is pressed into the flange blank 20 from the upper surface side, as... Figure 7 As shown, during the precision cutting, the second die 32 is also pressed into the flange blank 20 from the upper surface side. As a result, the removed portion 20a is separated from the flange blank 20.

[0142] The gap C between the second die 32 and the second punch 42 32-42 [mm] represents the positive clearance. Clearance C 32-42The gap is represented by the distance between the side surface 32a of the second die 32 and the side surface 42a of the second punch 42. Here, similar to the half-cutting process, the gap when the second die 32 and the second punch 42 are separated is called the positive gap, and the gap when the second die 32 and the second punch 42 are partially overlapped is called the negative gap.

[0143] The gap C between the second die 32 and the second punch 42 32-42 As shown in the following formula (5), the value is set to be 0.01 mm or more and is less than 0.2 times the residual plate thickness t2 of the flange portion of the first blank 20 remaining after the half-cutting and removal of the portion 20a.

[0144] 0.01≤C 32-42 ≤0.2×t2…(5)

[0145] If the gap C 32-42 If the gap is 0.01mm or greater, even if there are issues such as slippage of the punch press or eccentricity of the die during precision cutting, there is no need to worry about the second die 32 coming into contact with the second punch 42 and breaking. On the other hand, if the gap C... 32-42 If the thickness of the residual plate is less than 0.2 times that of t2, then burrs 13e are less likely to form.

[0146] The tip of the second die 32 is an arc shape with a radius of curvature R2. For example... Figure 7 As shown, the second die 32 is pressed into the portion of the flange blank 20 for precision cutting; therefore, the tip of the second die 32 is set to an arc shape with a radius of curvature R2. Furthermore, the tip of the second punch 42 is as follows... Figure 7 The shape shown is a square without roundness. In this case, the tip of the second punch 42 can also 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 set to be less than 0.1 times the plate thickness t1 of the flange portion of the first blank 2, or it can be set to be less than 0.06 times, less than 0.04 times, or less than 0.02 times as needed.

[0147] The radius of curvature R2 [mm] is as shown in the following formula (6), and is set to be 0.25 mm or more and less than 1.50 times the residual plate thickness t2 of the part after half-cutting.

[0148] 0.25≤R²≤1.50×t²…(6)

[0149] If the radius of curvature R2 is 0.25 mm or more, the second die 32 will not remove the plating 13f that wraps around the shearing surface 13c. On the other hand, if the radius of curvature R2 is less than 1.50 times the residual plate thickness t2, burrs 13e are less likely to be generated.

[0150] Furthermore, when a cut-off end is formed on the outer periphery of the processed product 1, the inner diameter D of the second die 32 32 Let the inner diameter D of the first die 31 be... 31 In the case where a cut-off end is formed on the inner circumferential side of the processed product 1, the outer diameter d of the second die 32 is... 32 Let d be the outer diameter of the first die 31. 31 Specifically, when a cut-off end is formed on the outer periphery of the workpiece 1, the inner diameter D of the first die 31 is as follows. 31 With the inner diameter D of the second die 32 32 The absolute value of the difference |D 32 -D 31 | Preferably, it is 1.00 mm or less. When a cut-off end is formed on the inner circumferential side of the processed part 1, the outer diameter d of the first die 31 is... 31 The outer diameter d of the second die 32 32 The absolute value of the difference |d 32 -d 31 | Preferably, it is 1.00 mm or less. Therefore, by performing the two processes of partial cutting and fine cutting, the diameter difference D between the dies 31 and 32 can be minimized. 32 -D 31 or d 32 -d 31 The reduced step difference at the cut end 13 of the processed product 1 results in a better cut cross section.

[0151] Furthermore, as a quality metric for the processed product 1, the absolute value of the inner diameter difference when the cut-off end 13 is formed on the outer periphery of the processed product 1, assuming a permissible step difference, is |D|. 32 -D 31 |The absolute value of the outer diameter difference when a cut-off end is formed on the inner circumference of the processed part 1|d 32 -d 31 |It can also exceed 1.00mm. Furthermore, the absolute value of these diametrical differences |D 32 -D 31 | and |d 32 -d 31 The upper limit of | is preferably small, but can also be set to 0.75mm, 0.50mm, 0.35mm, or 0.20mm. The absolute value of the diameter difference |D 32 -D 31 | and |d 32 -d 31 The lower limit of | is 0 mm. Furthermore, the step difference generated at the cut end 13 of the processed article 1 is preferably small, and can also be set to 0.5 mm or less. The upper limit of the step difference generated at the cut end 13 of the processed article 1 can also be set to 0.4 mm, 0.3 mm, 0.2 mm, or 0.1 mm as needed.

[0152] (b. The case where the cutting tips of the die and punch used in the semi-cutting process are set to an arc shape)

[0153] Next, based on Figure 8 and Figure 9 The semi-cutting and fine-cutting processes are explained when the cutting tips of the die and punch used in the semi-cutting process are set to an arc shape. Figure 8 This is an explanatory diagram showing a semi-cutting process where the cutting tips of the die and punch used in the semi-cutting process are set to an arc shape. Figure 9 It means to continue Figure 8 A diagram illustrating the fine cutting process performed during the semi-cutting process.

[0154] (Semi-cutting process)

[0155] In the semi-cutting process, such as Figure 8 As shown, the flange portion of the first blank 20 is partially cut off using the first die 31 and the first punch 41. Figure 8 In, with Figure 6 Similarly, as one method of partial cutting, a method is shown where the flange portion 12 is partially punched from the flange portion blank 20 held by the first punch 41 and the first pressure plate 51. The first die 31 constitutes a cutting die that is pressed into the flange portion blank 20 during partial cutting. In this embodiment, the die that presses the portion of the flange portion blank 20 that becomes the flange portion 12 is designated as the first punch 41, and the die that presses and removes the portion 20a is designated as the first die 31.

[0156] The gap C between the first die 31 and the first punch 41 31-41 It is a negative gap. Therefore, as Figure 8 As shown, the first die 31 and the first punch 41, which cut the first blank 2 in half, are arranged in a manner that partially overlaps when viewed from the pressing direction of the first die 31. This is achieved by adjusting the gap C. 31-41 Setting the clearance to negative prevents the complete removal of portion 20a from the flange blank 20 during the partial cutting process, thus reducing edge collapse 13b. Furthermore, the clearance C in this method b... 31-41 The meanings of negative gap and positive gap are the same as in method a above.

[0157] In addition, by making the gap C 31-41With a negative clearance, a large hydrostatic pressure is generated in the area clamped by the first die 31 and the first punch 41. Therefore, the proportion of tensile stress generated between the material that becomes scrap after cutting (i.e., the removed portion 20a) and the flange material that becomes the flange portion 12 is reduced in the stress generated when the first die 31 is pressed into the flange blank 20. As a result, the material that becomes scrap after cutting and contacts the tip of the first die 31 tends to flow from the tip of the first die 31 towards the side 31a of the first die 31, increasing the penetration of the plating 13f into the shear surface 13c. Furthermore, due to the reduction in the proportion of tensile stress, the compressive stress increases, and the material that would normally flow towards the scrap side is pushed back towards the flange portion 12. As a result, the portion that becomes the collapsed edge 13b after cutting is also filled with material, reducing the collapse edge 13b.

[0158] In the adjacent direction between the first die 31 and the first punch 41 (in Figure 8 In 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, the first die 31 is configured such that the side 31a of the first die 31 is located within a range where the distance from the end of the flange blank 20 is less than twice the thickness of the flange blank 20 (i.e., flange 12) to perform a partial cut.

[0159] The gap C between the first die 31 and the first punch 41 31-41 [mm] is set to be less than -0.10 and more than -0.35 times the plate thickness t1 [mm] of the flange portion blank 20 (i.e., flange portion 12) of the first blank 2, as shown in formula (b1) below.

[0160] -0.35×t1≤C 31-41 ≤-0.10×t1…(b1)

[0161] If the gap C 31-41 If the thickness t1 of the flange blank 20 is less than -0.10 times, 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 will not occur during the partial cutting process, preventing complete cutting and avoiding a large fracture surface. This also prevents the portion 20a to be completely cut off from the flange blank 20 during the partial cutting process. On the other hand, if the gap C... 31-41 If the thickness of the flange blank 20 is more than -0.35 times that of 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 smaller, which can suppress the reduction of die life. Clearance C 31-41More preferably, the gap C is less than -0.15 times or less than -0.20 times the thickness t1 of the flange blank 20. 31-41 Alternatively, the thickness of the flange blank 20 can be more than -0.30 times or more than -0.25 times the plate thickness t1.

[0162] In this method, such as Figure 8 As shown, the tips of the first die 31 and the first punch 41 are circular arc-shaped. The radius of curvature R11 [mm] of the tip of the first die 31 and the radius of curvature R12 [mm] of the tip of the first punch 41 are, as shown in equations (b2-1) and (b2-2) below, set to be at least 0.10 times and less than 0.65 times the plate thickness t1 [mm] of the flange portion blank 20 (i.e., flange portion 12) of the first blank 2. Furthermore, the radius of curvature R11 of the tip of the first die 31 and the radius of curvature R12 of the tip of the first punch 41 may be the same or different.

[0163] 0.10×t1≤R11≤0.65×t1…(b2-1)

[0164] 0.10×t1≤R12≤0.65×t1…(b2-2)

[0165] If the radii of curvature R11 and R12 are 0.10 times or more of the plate thickness t1, a large hydrostatic pressure is generated under negative clearance without removing the plating 13f. This allows the scrap material directly below the first die 31 to flow from the tip of the first die 31 towards the side 31a of the first die 31. This flow reduces the proportion of tensile stress generated between the material that becomes scrap after cutting (i.e., the removed portion 20a) and the flange material that becomes the flange portion 12 in the stress generated when the first die 31 presses into the flange blank 20. As a result, the plating 13f can be wound around the shear surface 13c. On the other hand, if the radii of curvature R11 and R12 are set to 0.65 times or less of the plate thickness t1, the material at the tip of the first die 31 during partial cutting is reduced, which reduces the formation of the fracture surface 13d during the subsequent fine cutting.

[0166] The pressing amount D [mm] of the first die 31 into the flange portion 20 (i.e., flange portion 12) of the first blank 2 is set to at least 0.70 times the plate thickness t1 [mm] of the flange portion 20 (i.e., flange portion 12) of the first blank 2, as shown in formula (b3) below. 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 flange portion 20 of the first blank 2 to the position where the pressing of the first die 31 stops (bottom dead center). The distance C between the first die 31 and the first punch 41 at the bottom dead center is... P-D [mm] is set to 0.20 mm or more as shown in formula (b4) below.

[0167] D≥0.70×t1…(b3)

[0168] C P-D ≥0.20…(b4)

[0169] The residual plate thickness t2 of the flange portion of the first blank 20 remaining after the partial cut is removed can also be set to 0.30 times or less of the plate thickness t1 [mm] of the flange portion of the blank 20. If the pressing amount D is more than 0.70 times the plate thickness t1, it is less likely to generate a fracture surface 13d in the subsequent fine cut. On the other hand, by adjusting the spacing C between the first die 31 and the first punch 41 at the lower stop point... P-D To ensure the cut is at least 0.20mm, cracks can be generated during the partial cutting process, preventing localized complete cutting. Furthermore, the interval C... P-D It is the minimum value of the interval between the first die 31 and the first punch 41 at the lower dead center.

[0170] By setting the cutting tips of the first die 31 and the first punch 41 to an arc shape, as shown in the example... Figure 6 Compared to the case where only the cutting tip of the first die 31 and the first punch 41 is rounded, the cutting amount of the flange blank 20 in the semi-cutting process can be increased. That is, by making the cutting tips of the first die 31 and the first punch 41 rounded, compared to... Figure 6 Compared to the case where only the tip of the first die 31 and the first punch 41 is set to an arc shape, the residual plate thickness t2 of the blank 20 remaining in the flange portion after the half-cutting removal portion 20a can be reduced.

[0171] When only the tip of the first die 31 is rounded, as in method a described above, if 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, the tip of the first die 31 will contact the tip of the first punch 41. Therefore, in method a described above, the pressing amount D of the first die 31 cannot be set to be greater than or equal to the plate thickness t1 of the flange portion 12. However, if the tips of both the first die 31 and the first punch 41 are rounded, then... Figure 8 As shown, the amount that the first die 31 can press in until the tip of the first die 31 contacts the tip of the first punch 41 is increased. Therefore, compared with method a, the cutting amount of the flange blank 20 can be further increased, and the proportion of the shear surface 13c of the cut end 13 can be increased. As a result, the plating layer 13f can be wrapped more around the shear surface 13c, 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.

[0172] (Precision cutting process)

[0173] In the precision cutting process, such as Figure 9 As shown, the flange blank 20, after being cut in half, is precision cut using the second die 32 and the second punch 42. The precision cutting process only needs to be performed in conjunction with... Figure 7 The fine cutting process shown can be performed by setting the tip of only one of the first die 31 and the first punch 41 to an arc shape and then performing a partial cut.

[0174] exist Figure 9 In this embodiment, as a method of precision cutting, a flange portion 12 is shown being precision-cut from a flange portion blank 20 held by a second punch 42 and a second pressure plate 52. A second die 32 constitutes a cutting die pressed into the flange portion blank 20 during precision cutting. In this embodiment, the die that presses down the portion of the flange portion blank 20 that becomes the flange portion 12 is used as the second punch 42, and the die that presses down the portion 20a to be removed is used as the second die 32. The second die 32 may also be the same as the first die 31. That is, the first die 31 used in the semi-cutting process may also be used as the second die 32 in the precision cutting process.

[0175] The positional relationship between the second die 32 and the first blank 2 is preferably the same as that between the first die 31 and the first blank 2. If their positional relationships are different, for example, if the diameter of the second die 32 is larger than the diameter of the first die 31, a step difference will be generated at the cut-off end 13. Conversely, for example, if the diameter of the second die 32 is smaller than the diameter of the first die 31, the second die 32 will contact the cut-off end generated in the half-cutting process, raising concerns that the second die 32 might remove the plating 13f wrapped around the shearing surface 13c.

[0176] In this embodiment, the fine cut is performed in the same direction as the partial cut. That is, as... Figure 8 As shown, during the semi-cutting process, when the first die 31 is pressed into the flange blank 20 from the upper surface side, as... Figure 9 As shown, during the precision cutting, the second die 32 is also pressed into the flange blank 20 from the upper surface side. As a result, the removed portion 20a is separated from the flange blank 20.

[0177] The gap C between the second die 32 and the second punch 42 32-42 [mm] is set as positive clearance. The clearance C between the second die 32 and the second punch 42. 32-42 As shown in formula (5) above, the value is set to be 0.01 mm or more and is less than 0.2 times the residual plate thickness t2 of the flange portion of the first blank 20 remaining after the half-cutting and removal of the portion 20a. If the gap C 32-42If the gap is 0.01mm or greater, then during precision cutting, even if there are issues such as slippage of the punch press or eccentricity of the die, the second die 32 will not come into contact with the second punch 42 and break. On the other hand, if the gap C... 32-42 If the thickness of the residual plate is less than 0.2 times that of t2, then burrs 13e are less likely to form.

[0178] The tip of the second die 32 is an arc shape with a radius of curvature R2. For example... Figure 9 As shown, the second die 32 is pressed into the portion of the blank 20 that is being precisely cut into the flange portion; therefore, the tip of the second die 32 is set to an arc shape with a radius of curvature R2. Furthermore, the tip of the second punch 42 can be... Figure 9 The square shape without roundness shown can also have a radius of curvature. If the tip of the second punch 42 is set to be a square without roundness, the burrs generated at the tip of the fracture surface 13d can be further reduced. The radius of curvature of the tip of the second punch 42 can be set to less than 1.00 mm, less than 0.50 mm, less than 0.20 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 also be set to be less than 0.3 times the plate thickness t1 of the flange portion of the first blank 2, or it can be set to be less than 0.1 times, less than 0.06 times, less than 0.04 times, or less than 0.02 times the plate thickness t1 as needed.

[0179] The radius of curvature R2 [mm], as shown in equation (6) above, is set to be 0.25 mm or more and less than 1.50 times the remaining plate thickness t2 of the partially cut portion. If the radius of curvature R2 is 0.25 mm or more, the second die 32 will not remove the plating 13f that wraps around the shearing surface 13c. On the other hand, if the radius of curvature R2 is less than 1.50 times the remaining plate thickness t2, burrs 13e are less likely to be generated.

[0180] The above describes the manufacturing method of the processed article according to the first embodiment of the present invention. According to this embodiment, the manufacturing method of the processed article includes: a semi-cutting process, in which a first blank 2 formed of plated steel sheet and having a flange blank 20 forming a flange portion 12 is used as the cutting object, and the flange blank 20 of the first blank 2 is semi-cut using a first die 31 and a first punch 41 with the gap between the first die 31 and the first punch 41 set to a negative gap; and a fine cutting process, in which the flange blank 20 after being semi-cut is finely cut using a second die 32 and a second punch 42 from the same direction as the semi-cutting process, to obtain a processed article 1 having a cut end 13 in the flange portion 12.

[0181] The cut end 13 of the flange portion 12 of the processed product 1, cut through these two processes, sequentially has a collapsed edge 13b, a shear surface 13c, and a fracture surface 13d in the thickness direction T of the cut end 13. At least a portion of the shear surface 13c is covered by the plating layer 13f of the upper surface 13a. At this time, the ratio L / t1 of the residual length L of the plating component covered by the plating layer 13f on the shear surface 13c to the thickness t1 of the cut end 13 of the processed product 1, is 0.70 or more, and the length of the collapsed edge 13b in the thickness direction T of the cut end 13 is a value greater than 0 times and less than 0.10 times the thickness t1 of the cut end 13 of the processed product 1. Thus, in the processed product 1, the collapse edge 13b of the cut end 13 is prevented from becoming larger, allowing more plating layer 13f to wrap around the shear surface 13c. Even when using plating steel sheets with a thickness exceeding 2.0 mm as raw materials, good corrosion resistance and shape quality can be achieved.

[0182] By reducing the length (collapse edge X) of the collapsed edge 13b in the planar direction (XY plane direction), the material used in the processed product 1 can be reduced. For example, as Figure 1 As shown, a screw hole 121 for inserting a screw 123 to fix the workpiece 1 is formed in the flange portion 12, avoiding the collapsed edge 13b, so that the screw 123 is fixed in the flat portion. Figure 10 As shown above, when the collapse edge X is large, the distance from the end of the flange 12 to the screw hole 121 is longer, requiring additional material. On the other hand, as... Figure 10 As shown below, if the drooping edge X is small, the distance from the end of the flange portion 12 to the screw hole 121 is shorter, thereby reducing the material used to form the flange portion 12. Thus, using the workpiece manufacturing method of this embodiment, it is not necessary to additionally increase the blank size in order to ensure the flatness of the periphery of the screw 123 required to fix the workpiece 1.

[0183] Furthermore, according to the processing method of this embodiment, more plating layer 13f can be wound into the shearing surface 13c, thus suppressing the red rust that will form on the cut end 13 over time after the cutting process.

[0184] Furthermore, the gap C between the second die 32 and the second punch 42 32-42 The residual plate thickness t2 of the first blank 2 (flange blank 20) ​​after partial cutting is set to be less than 0.2 times the thickness t2 of the portion above 0.01 mm. This avoids damage due to contact with the cutting die during fine cutting and suppresses the formation of burrs 13e.

[0185] Furthermore, the tip of the second die 32, which is pressed into the first blank 2 and is intended for fine cutting, has a curved shape with a radius of curvature R2 of 0.25 mm or more and less than 1.50 times the residual plate thickness t2 of the partially cut portion. This prevents the cutting die from removing the plating 13f that wraps around the shearing surface 13c, and also suppresses the formation of burrs 13e.

[0186] [2. Second Implementation]

[0187] Next, based on Figure 11 The method for manufacturing a processed article according to the second embodiment of the present invention will be described. Figure 11 This is an explanatory diagram illustrating a method for manufacturing a processed article according to the second embodiment of the present invention. (See diagram below.) Figure 11 As shown, the processing method of this embodiment includes a preparation process, a semi-cutting process, a precision cutting process, and a precision pressing process.

[0188] The processing method of this embodiment is in Figure 5 The first embodiment of the processed article manufacturing method shown includes an additional precision pressing process. For example... Figure 11 As shown, in this embodiment, similar to the first embodiment, the first blank 2 prepared in the preparation process is subjected to a semi-cutting process and a fine cutting process. Therefore, detailed descriptions of the preparation process, the semi-cutting process, and the fine cutting process are omitted.

[0189] In the precision pressing process, the workpiece obtained in the precision cutting process is used as the second blank 6, and the second blank 6 is precision pressed. In the precision pressing process, after the precision cutting process, the corner 13g of the cut end 13 near the fracture surface 13d is pressed against the pad. Figure 12 By using a pad 7), a finished product 1 with a finely pressed surface 13h formed at the corner is obtained. Through fine pressing, the area of ​​the fracture surface 13d, which is a rough surface, can be narrowed, and the area where red rust is generated can be suppressed. In addition, through fine pressing, the burrs 13e can be flattened, thereby more reliably suppressing the residue of burrs 13e in the finished product 1.

[0190] based on Figures 12-14 The precision pressing process will be explained in further detail. Figure 12 This is an explanatory diagram showing the precision pressing process. Figure 13 The image shows the cut end of the processed product 1 after the precision pressing process. The left side is a cross-sectional view at the ZX plane including the central axis of the processed product 1, and the right side is a side view from the X direction. Figure 14 This is a photograph showing an example of the cut end of the finished product 1 after the precision pressing process. Furthermore, in Figure 13 In, with Figure 2 Similarly, the description of coating 13f is omitted.

[0191] like Figure 12 As shown, in the precision pressing process of this embodiment, the cut end 13 of the second blank 6 is clamped in using the pad 7 and the precision pressing block 8. The pad 7 has a longitudinal wall surface 70, a bottom wall surface 71, and a pressing surface 72.

[0192] When the cut end 13 of the second blank 6 is clamped using the pad 7 and the precision pressing block 8, the longitudinal wall surface 70 is positioned opposite to and approximately parallel to the sheared surface 13c of the second blank 6. The longitudinal wall surface 70 is positioned relative to the advancing and retracting direction of the precision pressing block 8 (in... Figure 12 The configuration is parallel to each other (in the Z direction).

[0193] The bottom wall surface 71 is arranged opposite the precision pressing block 8 in the thickness direction of the flange portion 12, with the second blank 6 in between. The bottom wall surface 71 extends below the longitudinal wall surface 70 (i.e., on the side opposite to the precision pressing block 8) in a direction orthogonal to the longitudinal wall surface 70.

[0194] The pressing surface 72 is the surface connecting the longitudinal wall surface 70 and the bottom wall surface 71. The pressing surface 72 is for forming a precision pressing surface on the second blank 6. Figure 13 The shape is set for the fine pressing surface (13h) and formed to correspond to the shape of the fine pressing surface. For example, as Figure 13 As shown, when the fine pressing surface 13h is a flat, chamfered surface (hereinafter referred to as "C surface"), the pressing surface 72 only needs to be a plane inclined relative to the longitudinal wall surface 70 and the bottom wall surface 71. Alternatively, for example, when the fine pressing surface 13h is a curved surface (which can be either the pressing surface or the compression surface, hereinafter referred to as "R surface"), the pressing surface 72 can be a curved surface.

[0195] In the precision pressing process, such as Figure 12 As shown, with the cut end 13 of the second blank 6 facing the longitudinal wall surface 70 of the pad 7, the second blank 6 is clamped in the thickness direction T by the precision pressing block 8 and the bottom wall surface 71 of the pad 7. Then, the precision pressing block 8 is pressed towards the bottom wall surface 71, pressing the second blank 6 down until the bottom surface 13k of the second blank 6 contacts the bottom wall surface 71. Here, before the bottom surface 13k of the second blank 6 contacts the bottom wall surface 71, the corner portion 13g is pressed against the pressing surface 72. After the corner portion 13g is pressed against the pressing surface 72, the precision pressing block 8 is pressed further in, so that the bottom surface 13k of the second blank 6 contacts the bottom wall surface 71. The corner portion 13g is flattened by the pressing surface 72, becoming the precision pressing surface 13h. The cut end 13 of the processed product 1 after the precision pressing process becomes, for example, the cut end 13 of the processed product 1. Figure 14 The state shown in the photo.

[0196] The precision-pressed surface 13h is a smooth surface on which the pressing surface 72 is transferred, and it is less prone to developing red rust compared to the rough surface of the fracture surface 13d. This is believed to be because by making the surface rough and smooth, moisture is less likely to remain in the precision-pressed surface 13h. In addition, the thinner plating layer 13f on the bottom surface 13k side of the cut end 13 extending towards the precision-pressed surface 13h is also considered to be a factor that makes it less prone to developing red rust. By forming the precision-pressed surface 13h at the corner 13g on the side of the fracture surface 13d, the fracture surface length W2 of the flange portion 12 in the thickness direction T after precision pressing is (refer to...). Figure 13 The length W1 of the fracture surface of the flange portion 12 in the thickness direction T before precision pressing is compared to (refer to) Figure 2 and Figure 3 Short. That is, by precision pressing, the area of ​​the fracture surface 13d, which is a rough surface of the newly formed surface, can be narrowed, and the area where red rust is generated can be suppressed. In addition, by precision pressing, the burrs 13e can be flattened, thereby more reliably suppressing the residue of burrs 13e in the processed product 1.

[0197] In the precision pressing process, the pressing surface 72 is pressed against the corner 13g, so that the length (fracture length) W2 of the fracture surface 13d between the shear surface 13c in the thickness direction T of the flange portion 12 of the processed product 1 and the precision pressing surface 13h is set to a value that is greater than 0 mm and less than 0.5 mm. By setting the fracture length W2 to a value that is greater than 0 mm and less than 0.5 mm, even if red rust appears on the fracture surface 13d, it will not be noticeable, so it can be determined that it will not cause problems in practical use.

[0198] Furthermore, in the precision cutting process, it is preferable to obtain a second blank 6 with a fracture surface length W1 in the thickness direction T that is less than 1.0 mm. By obtaining a second blank 6 with a fracture surface length W1 of less than 1.0 mm, the fracture surface length W2 can be more reliably set to 0.5 mm or less in the precision pressing process. The fracture surface length W2 of the processed product 1 is preferably small, and can be set to 0.4 mm or less or 0.3 mm or less. It is even more preferable to set the fracture surface length W2 of the processed product 1 to 0.2 mm or less or 0.1 mm or less. In addition, the ratio W2 / t1 of the fracture surface length W2 to the thickness t1 of the cut end 13 of the processed product 1 can also be set to less than 0.15, less than 0.10, less than 0.08, less than 0.06, or less than 0.04. Furthermore, the fracture surface length W2 of the processed product 1 can also be 0 mm. That is, it is also possible that there is no fracture surface 13d at the cut end 13 of the processed product 1. That is, for example, Figure 13 As shown, the cutting end 13 may also have a collapsed edge 13b, a shearing surface 13c, a fracture surface 13d, and a fine pressing surface 13h in sequence along the thickness direction of the plate. Alternatively, the cutting end 13 may also have a collapsed edge 13b, a shearing surface 13c, and a fine pressing surface 13h in sequence along the thickness direction of the plate.

[0199] Figure 15 It means being Figure 12 A diagram illustrating the volume of the flattened corner 13g of the pressing surface 72 of the pad 7. With... Figure 12 The pressure block 8 is pressed down towards the bottom wall surface 71 of the pad 7, causing the corner portion 13g to contact the pressing surface 72 and be flattened. The material (base steel) of the flattened corner portion 13g moves along the pressing surface 72 towards the shearing surface 13c. When the cut end 13 is pressed down to the position where the bottom surface 13k of the cut end 13 contacts the bottom wall surface 71, the volume V1 of the corner portion 13g of the flange portion 12 flattened by the pressing surface 72 changes according to the position and angle of the pressing surface 72.

[0200] In the precision pressing process, such as Figure 15 As shown above, the volume V1 of the corner 13g flattened by the pressing surface 72 is preferably set to be less than or equal to the volume V2 of the fine pressing space enclosed by the extended surface 13j of the shear surface 13c, the fracture surface 13d, and the pressing surface 72. Figure 12 As shown, the fracture surface 13d of the cut end 13 of the flange 12 is inclined relative to the longitudinal wall surface 70, and there is a gap between them. The volume V2 of the fine pressing space created by this gap becomes the space for the material of the corner 13g flattened by the pressing surface 72 to flow in. If the volume V2 of the fine pressing space is smaller than the volume V1 of the corner 13g flattened by the pressing surface 72, the material of the corner 13g flattened by the pressing surface 72 cannot be contained in the volume V2, and moves towards the upper part of the pad 7.

[0201] Therefore, by setting volume V1 to be less than volume V2, it is possible to prevent the material of the corner 13g, which is flattened by the pressing surface 72, from protruding beyond the extension surface 13j of the shear surface 13c. Figure 15 As shown below, when volume V1 exceeds volume V2, the material of the corner 13g, which is flattened by the pressing surface 72, protrudes beyond the extension surface 13j of the shearing surface 13c, causing phenomena such as movement towards the upper part of the pad 7. When such phenomena occur, the dimensional accuracy of the cut end 13 deteriorates. Therefore, it is preferable to process the corner 13g by flattening it using the pressing surface 72 so that volume V1 is less than or equal to volume V2.

[0202] The manufacturing method of the processed article according to the second embodiment has been described above. According to this embodiment, similar to the first embodiment, it is not necessary to increase the blank size additionally in order to ensure the flatness of the periphery of the screw 123 required to fix the processed article 1. In addition, more plating 13f can be wrapped around the shearing surface 13c, thus suppressing the red rust that will form on the cut end 13 over time after the cutting process.

[0203] Furthermore, by performing a precision pressing process after the precision cutting process, the area of ​​the fracture surface 13d, which is a rough surface, can be narrowed, thus suppressing the area where red rust forms. Additionally, the precision pressing process flattens the burrs 13e, resulting in less than 0.2 mm of residual burrs 13e in the processed product 1, thereby more reliably suppressing burr 13e residue. The length of the burrs 13e is preferably less than 0.1 mm, more preferably less than 0.05 mm or less than 0.01 mm. Most preferably, the length of the burrs 13e is 0 mm, meaning that no burrs 13e are present in the processed product 1.

[0204] [3. Example of processed products]

[0205] In the above embodiments, the processed product 1 is Figure 1 The case of the motor housing shown has been described, but the processed article 1 manufactured using the processed article manufacturing method in this embodiment can be any article with a cut-off end 13 made of plated steel sheet as raw material.

[0206] Processed product 1 can also be, for example, Figure 16 The circular flat washer 900 is shown. Alternatively, the processed part 1 could also be, for example, a... Figure 17 The flat washers 910A, 910B, and 910C shown have teeth 911. Alternatively, the processed article 1 may also be, for example, a... Figure 18 The waveform shown is a circular disc spring 920. Figure 18 For example, the disc spring 920 can pass through... Figure 16 The flat washer 900 shown is manufactured by machining a wave pattern. Furthermore, the machined product can also be, for example, […]. Figure 19 The disc spring 930 shown has teeth 931.

[0207] In processed product 1 is Figures 16-19 When various annular plate components are shown, their outer and inner peripheral portions become cut-off ends 13. By applying the workpiece manufacturing method in the above embodiment, for at least one of the outer and inner peripheral portions, in the plate thickness direction T of the workpiece 1, the ratio L / t1 of the residual length L of the plating component covered by the plating layer 13f on the shear surface 13c to the plate thickness t1 of the cut-off end 13 of the workpiece 1 is 0.70 or more, and the length of the collapsed edge 13b is less than 0.10 times the plate thickness t1 of the cut-off end 13 of the workpiece 1.

[0208] For example, in order to utilize the coating to cover Figure 16 The shear surfaces of the inner and outer circumferential surfaces of the flat washer 900 shown can be used as long as... Figure 20 and Figure 21 The cutting die shown can be used for processing. Figure 20 This is a schematic diagram showing an example of a cutting die used to process a flat washer 900. Figure 21It means to utilize Figure 20 A schematic diagram showing the state of the cutting die punching the blank 9.

[0209] Figure 20 The cutting die shown is a die for manufacturing annular processed products 90 such as flat washers 900, and has a hollow cylindrical die (hereinafter referred to as the "outer die") 61, a cylindrical die (hereinafter referred to as the "inner die") 63, and a supporting plate-shaped blank 9 (see reference). Figure 21 A hollow cylindrical punch 65 is provided. An outer die 61 and an inner die 63 are disposed opposite to the punch 65. The blank 9 is cut off by pressing the outer die 61 and the inner die 63 into the blank 9 supported by the punch 65. The inner diameter of the outer die 61 corresponds to the outer diameter of the workpiece 90, and the outer diameter of the inner die 63 corresponds to the inner diameter of the workpiece 90. The cutting tips of the inner circumferential surface of the outer die 61 and the cutting tips of the outer circumferential surface of the inner die 63 have an arc shape with a radius of curvature. On the other hand, the edges of the inner and outer circumferential surfaces of the punch 65 do not have an arc shape.

[0210] When such a cutting die is used to precisely cut the blank 9, such as Figure 21 As shown, the portion 9a on the outer side of the outer peripheral surface 91 of the workpiece 90 is cut off by the outer die 61, and the portion 9b on the inner side of the inner peripheral surface 92 of the workpiece 90 is cut off by the inner die 63. This forms... Figure 20 The processed part 90 (flat washer 900) is shown. At this time, in the shearing surfaces of the outer peripheral surface 91 and the inner peripheral surface 92 of the processed part 90, the ratio L / t1 of the residual length of the plating component covered by the plating layer to the plate thickness t1 of the cut end of the processed part 90 is 0.70 or more, and the length of the collapsed edge in the plate thickness direction of the cut end can be less than 0.10 times the plate thickness t1 of the cut end of the processed part 90.

[0211] Furthermore, processed product 1 can also be, for example, Figure 22 The circular plate 940 shown.

[0212] Example

[0213] (Example a. The case where the tip of the die used in the semi-cutting process is only rounded)

[0214] The shoulder (i.e., the tip) of the die in the semi-cutting process is set as an arc shape with a predetermined radius of curvature, utilizing... Figure 5 and Figure 11 Samples of the processed products are prepared using the method shown. As the plated steel sheet, a sheet thickness of 1.4 mm to 3.8 mm and a plating adhesion of 90 g / m² are used. 2 (single-sided) or 190g / m 2(Single-sided) Zn-6%Al-3%Mg (mass ratio) alloy-coated steel sheet. Semi-cutting process using inner diameter D. 31 A circular die with a diameter of 85.00 mm and a punch whose diameter is adjusted according to the clearance between the die and the punch are used to hold the plated steel sheet using a pressure plate. Precision cutting is performed using a die with a shoulder (i.e., the cutting tip) set in an arc shape with a predetermined radius of curvature, and a die with a clearance C between the die and the punch. 32-42 And change the diameter D 32 The punch uses a pressure plate to hold the plated steel sheet in place.

[0215] For each sample, the collapse lengths Z and X, the fracture surface length (W1) after precision cutting, and the fracture surface length (W2) after precision pressing were measured. These measurements were taken at 30° intervals along the circumference of the end face of the workpiece using a microscope, and the values ​​from a total of 12 points were averaged. Additionally, for each sample, regarding the coating's infiltration into the cut end, the length L of the coating infiltrating along the thickness direction of the coated steel sheet was measured from the cross-section of the central portion of the straight edge of the workpiece. The length L of the coating at the cut end was measured using an electron probe microanalyzer (EPMA-WDS). A coating was determined to exist in portions where the Zn content detection level was more than three times the background level. Furthermore, the measurements were taken from workpieces after precision cutting, second blanks, and workpieces after precision pressing.

[0216] In addition, at the cut ends of each sample, there are collapsed edges, shear surfaces, fracture surfaces, and fine-pressed surfaces, such as... Figure 14 As shown, and more specifically as described below.

[0217] Edge collapse occurs when a die, after contacting the workpiece, applies compressive (pressure) force, stretching the surface of the workpiece to form a smooth surface. For example... Figure 3 As shown, when viewed from the side, the cut end has a curved shape.

[0218] The sheared surface appears as a smooth surface at the cut end. It is generated by the die cutting into the workpiece after contact with it under compressive (pressure) force, resulting in friction against the side of the die. Because it is generated through friction with the die, the sheared surface exhibits a metallic luster. Fine, strip-shaped sliding damage can be seen on the sheared surface along the thickness direction.

[0219] A fracture surface is a surface formed by the convergence of cracks generated on the workpiece from the shearing side, and it appears as a rough, dull surface. After the workpiece is sheared, as the die further cuts into the workpiece, cracks are generated in the workpiece by the tip of the punch, and also by the tip of the die. The cracks generated from the punch and die converge and continue through each other. The surface formed by cracks generated in this way is called a fracture surface. The fracture surface is formed without contact between the punch and the die, therefore it is a rough, dull surface. The fracture surface has an inclination corresponding to the clearance between the punch and the die.

[0220] The precision-pressed surface is characterized by a smooth surface formed by flattening the unevenness of the fracture surface. It is obtained by pressing a beveled or curved precision-pressing mold against the corner of the fracture surface from the lower surface side of the fracture end. The precision-pressed surface achieves its smooth surface by transferring the surface roughness of the precision-pressing mold, thus flattening the unevenness of the fracture surface.

[0221] As a method for determining the collapsed edge, shear surface, fracture surface, and fine pressing surface at the cut end, for example, there is a method that measures the shape and profile of the cut end by observing its appearance using a microscope or a contour shape measuring instrument based on the above characteristics.

[0222] From the perspective of ensuring the flatness of the area around the fixing screw, samples with a collapse edge Z of less than 0.10 times at the cut end 13 are evaluated as "A (Pass)", and samples with a collapse edge Z of more than 0.10 times are evaluated as "B (Fail)". For burrs that cause scratches, short circuits, etc., samples with a size less than 0.2 mm are evaluated as "A (Pass)", and samples with a size greater than 0.2 mm or with whisker-like burrs are evaluated as "B (Fail)". Furthermore, in terms of appearance and product dimensional accuracy, it is desirable to minimize the step difference on the end face. Therefore, samples with an end face step difference of less than 0.5 mm are evaluated as "A (Pass)", and samples with a step difference greater than 0.5 mm are evaluated as "B (Fail)".

[0223] In addition, the samples were subjected to atmospheric exposure tests outdoors, and the number of days observed every 15 days until noticeable red rust appeared at the cut ends.

[0224] The results are presented in Table 1. Table 1 shows the conditions of the plated steel sheet used in each sample, the semi-cutting process, the fine cutting process, and whether or not the corners of the cut ends were precision pressed. Here, the ratio of the die's radius of curvature to its thickness (R1 / t1, R2 / t2) is obtained by dividing the roundness of the die's shoulder by the sheet thickness. Samples for which the roundness of the die's shoulder (blade tip) was not intentionally imparted are marked as "<0.01" in this column.

[0225] [Table 1]

[0226]

[0227] As shown in Table 1, in Examples a1 to a19, the ratio of the residual length L of the plating component to the plate thickness t1 at the cut end is 0.70 times or more, and the size of the collapsed edge Z appearing in the plate thickness direction is less than 0.10 times the plate thickness t1 at the cut end of the processed product. The fracture surface length W1 at the cut end is 1.0 mm or less in all examples a1 to a19, and examples a1 to a19 show good corrosion resistance for 60 days before red rust forms. In Examples a1 to a13, the size of the collapsed edge X appearing in the planar direction is less than 0.30 times the plate thickness t1 at the cut end of the processed product. In Examples a1 to a16, where the fracture surface length W1 at the cut end is 0.5 mm or less, good corrosion resistance for more than 90 days before red rust forms is shown.

[0228] In Examples a1 to a14, the ratio of the residual length L of the plating component to the plate thickness t1 of the cut end of the processed workpiece is 0.80 times or more, and the fracture surface length (W1) is 0.5 mm or less. Furthermore, in Example a15, after fine blanking, a fine pressing process was performed to form an R-surface with a flattened edge length (width of the fine pressing surface) of 0.6 mm. In Example a16, after fine blanking, a fine pressing process was performed to form a C-surface with a flattened edge length (width of the fine pressing surface) of 1.0 mm and a chamfered angle of 45°. The fracture surface length (W2) after fine pressing is smaller than the fracture surface length W1 of the other examples. Regarding the diameter D of the die for the semi-cutting process... 31 The diameter D of the die for precision cutting 32 The absolute value of the difference |D 32 -D 31 |, in Examples a1 to a17, it is 0.05 mm, and in Example a18, it is zero (diameter D) 31 With diameter D 32 (Same), in example a19 it is 1.00 mm, but in any case the step difference of the end face is less than 0.5 mm.

[0229] Furthermore, based on the above features, the following were confirmed from the appearance: the cut ends of embodiments a1 to a14, a18, and a19 have a collapsed edge, a shearing surface, and a fracture surface in sequence in the plate thickness direction; the cut ends of embodiments a15 and a16 have a collapsed edge, a shearing surface, a fracture surface, and a fine pressing surface in sequence in the plate thickness direction.

[0230] In contrast, in Comparative Examples a1-a5, a8, a10-a13, and a16, the ratio of the residual length L of the coating component to the plate thickness t1 at the cut end of the processed product was less than 0.70 times. Therefore, the number of days before red rust formed at the cut end was less than 60 days, resulting in poorer corrosion resistance compared to the examples. Comparative Example a9 used a large negative clearance in the semi-cutting process, but it became overloaded in the semi-punching process using a 750kN mechanical press, causing the press to stop. Comparative Examples a14 and a15 both showed good corrosion resistance with more than 90 days before red rust formed at the cut end, but large burrs of more than 0.2 mm formed at the cut end.

[0231] Comparative Example a6 demonstrates good corrosion resistance for more than 90 days before red rust forms at the cut end. However, the size of the collapsed edge Z in the thickness direction is more than 0.10 times the thickness of the flange blank, and the size of the collapsed edge X in the planar direction is more than 0.30 times the thickness of the finished product. Therefore, the flange size must be increased accordingly when tightening screws. Comparative Example a7 shows the case where the clearance between the die and punch in the semi-cutting process is set to zero, resulting in complete breakage of the plated steel sheet during the semi-cutting process.

[0232] (Example b. The case where the cutting tips of the die and punch used in the semi-cutting process are set to an arc shape)

[0233] Next, the shoulders (i.e., the blade tip) of the die and punch in the semi-cutting process are set into an arc shape with a predetermined radius of curvature, utilizing... Figure 5 and Figure 11 Samples of the processed products are prepared using the method shown. As the plated steel sheet, a sheet thickness of 1.4 mm to 4.5 mm and a plating adhesion of 90 g / m² are used. 2 (single-sided) or 190g / m 2 (Single-sided) Zn-6%Al-3%Mg (mass ratio) alloy-coated steel sheet. Semi-cutting is performed using a circular die with an inner diameter of 85.00 mm and a punch whose diameter is adjusted according to the gap between the die and the punch head, with the coated steel sheet held in place by a pressure plate. Finish cutting is performed using a die with a predetermined radius of curvature on the shoulder (i.e., the cutting tip) and a punch whose diameter is adjusted according to the gap between the die and the punch head, with the coated steel sheet held in place by a pressure plate.

[0234] For each sample, flatness, burr, and step difference were evaluated in the same manner as in Example a above, and the number of days of red rust formation based on atmospheric exposure tests was investigated. The results of Example b are shown in Table 2.

[0235] [Table 2]

[0236]

[0237] As shown in Table 2, in Examples b1 to b19, the ratio of the residual length L of the plating component to the plate thickness t1 of the cut end of the workpiece is 0.70 times or more, and the size of the collapsed edge Z appearing in the plate thickness direction is less than 0.10 times the plate thickness t1 of the cut end of the workpiece. The fracture surface length of the cut end is 1.0 mm or less in all of these examples, and Examples b1 to b19 demonstrate good corrosion resistance for 60 days before the formation of red rust. In Examples b1 to b13 and b15 to b19, the size of the collapsed edge X appearing in the planar direction is less than 0.30 times the plate thickness t1 of the cut end of the workpiece. In Examples b1 to b14, b16, and b17, the ratio of the residual length L of the plating component to the plate thickness t1 of the cut end of the workpiece is 0.80 times or more, and the fracture surface length (W1) is 0.5 mm or less, demonstrating good corrosion resistance for more than 90 days before the formation of red rust. Furthermore, in Example b16, after fine blanking, a fine pressing process was performed to form an R-surface with a flattened edge length (width of the fine pressing surface) of 0.6 mm. In Example b17, after fine blanking, a fine pressing process was performed to form a C-surface with a flattened edge length (width of the fine pressing surface) of 1.0 mm and a chamfered angle of 45°. The fracture surface length (W2) after fine pressing is smaller than in other examples. The diameter D of the die for the semi-cut-off process... 31 The diameter D of the die for precision cutting 32 The absolute value of the difference |D 32 -D 31 | In Examples b1 to b17, the value is set to 0.05 mm, and in Example b18, it is set to zero (diameter D). 31 With diameter D 32 (Same), in embodiment b19 it is set to 1.00 mm, but in any case the step difference of the end face is less than 0.5 mm.

[0238] Furthermore, based on the above features, it was confirmed from the appearance that the cut ends of embodiments b1 to b15, b18, and b19 have a collapsed edge, a shearing surface, and a fracture surface in the plate thickness direction in sequence, and the cut ends of embodiments b16 and b17 have a collapsed edge, a shearing surface, a fracture surface, and a fine pressing surface in the plate thickness direction in sequence.

[0239] In contrast, in Comparative Examples b1, b2, b4, b6-b8, b11, and b13, the ratio of the residual length L of the coating component to the plate thickness t1 at the cut end of the workpiece is less than 0.70 times. Therefore, the number of days before red rust forms at the cut end is less than 60 days, resulting in poorer corrosion resistance compared to the examples. Furthermore, in Comparative Examples b1 and b4, the size of the collapsed edge Z in the plate thickness direction is 0.10 times the plate thickness t1 at the cut end of the workpiece, thus insufficient flatness is not achieved. In Comparative Example b5, a large negative clearance is used in the semi-cutting process, but this becomes an overload in the semi-punching process using a 750kN mechanical press, causing the press to stop. Comparative Examples b9 and b10 show good corrosion resistance for more than 90 days before red rust forms at the cut end, but large burrs of more than 0.2 mm are produced at the cut end. In comparative examples b3 and b12, the negative clearance between the die and the punch in the semi-cutting process was insufficient, so the plated steel sheet completely broke during the semi-cutting process.

[0240] Based on the above, in the cutting process where a fine cutting process follows a semi-cutting process, it can be confirmed that the shape of the cut end is such that a cut end with good corrosion resistance is obtained by making the ratio of the residual length L of the plating component to the plate thickness t1 of the cut end of the workpiece at least 0.70 times. Furthermore, it has been confirmed that by making the slump Z appearing in the plate thickness direction of the cut end less than 0.10 times the plate thickness t1 of the cut end of the workpiece, a product is obtained that does not require an additional increase in flange size during screw tightening.

[0241] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to these examples. It should be understood that those skilled in the art will obviously be able to conceive of various modifications or alterations within the scope of the technical concept set forth in the claims, and these also fall within the protection scope of the present invention.

[0242] Explanation of reference numerals in the attached figures

[0243] 1. Finished product; 2. First blank; 6. Second blank; 7. Pad; 8. Precision pressing block; 9. Blank; 10. Main body; 11. Protrusion; 12. Flange; 13. Cut-off end; 13a. Upper surface; 13b. Collapsed edge; 13c. Sheared surface; 13d. Fracture surface; 13e. Burr; 13f. Plating; 13g. Corner; 13h. Precision pressing surface; 13j. Extended surface; 13k. Bottom surface; 20. Flange blank; 20 a. Removal section; 31. First die; 32. Second die; 41. First punch; 42. Second punch; 61. Outer die; 63. Inner die; 65. Punch; 70. Longitudinal wall; 71. Bottom wall; 72. Pressing surface; 101. Side wall; 103. Top wall; 121. Screw hole; 123. Screw; 900, 910A, 910B, 910C. Flat washer; 911, 931. Toothed part; 940. Plate.

Claims

1. A method for manufacturing a processed article, comprising using a plated steel sheet having a coating on its surface as raw material and having a cut-off end, wherein, The method for manufacturing the processed product includes: A partial cutting process, in which the first die and the first punch, with the gap between the first die and the first punch set to a negative gap, partially cut the cutting portion of the first blank formed from the raw material along the thickness direction; and In the precision cutting process, a second die and a second punch are used to precisely cut the first blank after it has been partially cut, from the same direction as the partial cut, to obtain a finished product with a cut end along the thickness direction of the plate. When a cut-off end is formed on the outer periphery of the workpiece, the inner diameter D of the second die... 32 Let D be the inner diameter of the first die. 31 In the case where a cut-off end is formed on the inner side of the processed workpiece, the outer diameter d of the second die is as follows: 32 Let d be the outer diameter of the first die. 31 the following, Let the thickness of the cut portion of the first blank be t1, and let the residual thickness of the cut portion after the semi-cutting process be t2. In the semi-cutting process, The gap C between the first die and the first punch 31-41 It satisfies the following equation (a1). The radius of curvature R1 of the tip of the first die satisfies the following formula (a2). The pressing amount D of the first die or the first punch relative to the cut portion of the first blank satisfies the following formula (a3). The distance C between the first die and the first punch at the lower stop point P-D It satisfies the following equation (a4). In the precision cutting process, The gap C between the second die and the second punch 32-42 It satisfies the following equation (a5). The radius of curvature R2 of the tip of the second die satisfies the following equation (a6): -0.25×t1≤C 31-41 ≤-0.01…(a1) 0.10×t1≤R1≤0.50×t1…(a2) D≥0.70×t1…(a3) W P-D ≥0.20…(a4) 0.01 ≤ C 32-42 ≤0.2×t2…(a5) 0.25≤R2≤1.50×t2…(a6), Here, C 31-41 C P-D C 32-42 And the unit of R2 is mm.

2. A method for manufacturing a processed article, comprising using a plated steel sheet having a coating on its surface as raw material and having a cut-off end, wherein, The method for manufacturing the processed product includes: A partial cutting process, in which the first die and the first punch, with the gap between the first die and the first punch set to a negative gap, partially cut the cutting portion of the first blank formed from the raw material along the thickness direction; and In the precision cutting process, a second die and a second punch are used to precisely cut the first blank after it has been partially cut, from the same direction as the partial cut, to obtain a finished product with a cut end having a cut surface along the thickness direction of the plate. When a cut-off end is formed on the outer periphery of the workpiece, the inner diameter D of the second die... 32 Let D be the inner diameter of the first die. 31 In the case where a cut-off end is formed on the inner side of the processed workpiece, the outer diameter d of the second die is as follows: 32 Let d be the outer diameter of the first die. 31 the following, Let the thickness of the cut portion of the first blank be t1, and let the residual thickness of the cut portion after the semi-cutting process be t2. In the semi-cutting process, The gap C between the first die and the first punch 31-41 It satisfies the following equation (b1). The radius of curvature R11 of the tip of the first die satisfies the following formula (b2-1). The radius of curvature R12 of the tip of the first punch satisfies the following formula (b2-2). The pressing amount D of the first die or the first punch relative to the cut portion of the first blank satisfies the following formula (b3). The distance C between the first die and the first punch at the lower stop point P-D It satisfies the following equation (b4). In the precision cutting process, The gap C between the second die and the second punch 32-42 It satisfies the following equation (b5). The radius of curvature R2 of the tip of the second die satisfies the following equation (b6): -0.35×t1≤C 31-41 ≤-0.10×t1…(b1) 0.10×t1≤R11≤0.65×t1…(b2-1) 0.10×t1≤R12≤0.65×t1…(b2-2) D≥0.70×t1…(b3) C P-D ≥0.20…(b4) 0.01≤C 32-42 ≤0.2×t2…(b5) 0.25≤R2≤1.50×t2…(b6), Here, C 31-41 C P-D C 32-42 And the unit of R2 is mm.

3. The method for manufacturing processed articles according to claim 1 or 2, wherein, The manufacturing method for this processed product also includes a precision pressing process, in which... The finished product obtained in the precision cutting process is used as the second blank. The corner of the cut end of the second blank is pressed against the pad to obtain a processed product with a fine pressing surface formed at the corner.

4. The method for manufacturing processed articles according to claim 1 or 2, wherein, When a cut-off end is formed on the outer periphery of the workpiece, the inner diameter D of the first die is... 31 With the inner diameter D of the second die 32 The absolute value of the difference |D 32 -D 31 | Set to below 1.00mm, When a cut-off end is formed on the inner side of the processed workpiece, the outer diameter d of the first die is... 31 With the outer diameter d of the second punch 32 The absolute value of the difference |d 32 -d 31 | Set to below 1.00mm.

5. The method for manufacturing processed articles according to claim 1 or 2, wherein, The manufacturing method for the processed product further includes a preparation step before the semi-cutting step, in which a first blank is formed from a flat plated steel sheet.

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