Processing equipment, methods of manufacturing metal components, and metal components.

Abstract

Invention details;

Description

Processing device, method for manufacturing metal member, and metal member

[0001] The present invention relates to a processing device, a method for manufacturing a metal member, and a metal member.

[0002] Steel components for automobiles and building materials are often manufactured by press working. When corrosion resistance is required for steel components, cold-rolled or hot-rolled steel sheets are pressed and then painted or plated. However, adding a painting or plating process after press working increases the work time and costs.

[0003] One possible solution to this problem is to press-form plated steel sheets. However, when plated steel sheets are subjected to press-forming processes that involve cutting, such as punching, the plating layer is separated at the cut edge, exposing the steel base. If the steel base is left exposed at the cut edge, corrosion will occur from the cut edge. Therefore, a process is required to plate the cut edge where the steel base is exposed, which increases work time and costs.

[0004] Japanese Patent Application Laid-Open No. 2017-87294 discloses a cutting method in which the clearance between the die and the punch is 1 to 20% of the thickness of the surface-treated steel sheet, and a die having a radius of curvature of 0.12 times or more the thickness of the surface-treated steel sheet is provided on the shoulder of at least one of the die and the punch.

[0005] Japanese Patent Application Laid-Open No. 2009-287082 describes a cutting method for cutting a zinc-based plated steel sheet using a mold consisting of a die, a punch, and a die holder, in which the shoulder of one of the die and the punch facing the product steel sheet is rounded with a radius of curvature that is 0.10 to 0.50 times the thickness of the steel sheet, the other shoulder and the shoulder of the die holder are at right angles, the sides of the die and the die holder are aligned, and the clearance between the die and the punch is 1.0% or less of the thickness of the steel sheet.

[0006] JP 2017-87294 A JP 2009-287082 A JP 2020-32437 A JP 2006-263755 A

[0007] Under the processing conditions of JP 2017-87294 A, under narrow clearance conditions, the occurrence of fracture surfaces can be suppressed and the length of the sheared surface can be increased, but the plating layer formed on the resulting sheared surface is limited to a small area. On the other hand, under wide clearance conditions, the length of the sheared surface is increased compared to conventional conditions, but a certain amount of fracture surfaces still occur. As a result, corrosion may occur on the sheared surface or on the fractured surface that is not covered with the plating layer.

[0008] Under the processing conditions of JP 2009-287082 A, although it is possible to suppress the occurrence of fracture surfaces and increase the length of the sheared surfaces, the plating layer formed on the obtained sheared surfaces is limited to a small area.

[0009] The object of the present invention is to provide a processing device capable of manufacturing metal components having excellent corrosion resistance at their cut end surfaces, a method for manufacturing metal components having excellent corrosion resistance at their cut end surfaces, and a metal component having excellent corrosion resistance at its cut end surfaces.

[0010] A processing device according to one embodiment of the present invention is a processing device that includes a punch and a die that are arranged on one side and the other side in the thickness direction of a metal plate that is a workpiece, and that shears the metal plate by moving at least one of the punch and the die in the thickness direction so that the punch and the die approach each other, wherein each of the punch and the die has an end face and a side face, the punch and the die are arranged so that the end face of the punch and the end face of the die do not overlap in a planar view, at least one of the side face of the punch and the side face of the die is inclined so that the surface faces toward the metal plate and includes an inclined portion formed so as to overlap the other of the punch and the die in a planar view, and the angle between the surface of the inclined portion and the thickness direction is 15° or more.

[0011] A method for manufacturing a metal component according to one embodiment of the present invention includes a step of shearing a metal plate having a plating layer on its surface using the above-described processing device.

[0012] A metal component according to one embodiment of the present invention is a metal component made of a metal plate having a plating layer on its surface, and has an inclined surface on its end face whose dimension in the plate thickness direction is 60% or more of the plate thickness and whose angle with the plate thickness direction is 15° or more, and at least a portion of the inclined surface is covered with the plating layer.

[0013] According to the present invention, a metal member having excellent corrosion resistance at the cut end surface can be obtained.

[0014] FIG. 1 is a cross-sectional view schematically showing the configuration of a processing apparatus according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view schematically showing shearing of a metal plate using the processing apparatus of FIG. 1. FIG. 3 is a perspective view of a metal member according to one embodiment of the present invention. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3. FIG. 5 is a cross-sectional view schematically showing the configuration of a processing apparatus according to a second embodiment of the present invention. FIG. 6 is a cross-sectional view schematically showing shearing of a metal plate using the processing apparatus of FIG. 5. FIG. 7 is a perspective view of a metal member according to one embodiment of the present invention. FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 7. FIG. 9 is a cross-sectional view schematically showing the configuration of a processing apparatus according to a third embodiment of the present invention. FIG. 10 is a cross-sectional view schematically showing shearing of a metal plate using the processing apparatus of FIG. 9. FIG. 11 is a cross-sectional view schematically showing the configuration of a processing apparatus according to a fourth embodiment of the present invention. FIG. 12 is a perspective view of a metal member according to one embodiment of the present invention. FIG. 13 is a contour map showing the distribution of stress within a metal plate during processing, calculated using the finite element method. Figure 14 is a cross-sectional photograph of the metal sheet just before it broke. Figure 15 is a graph showing the relationship between the angle θ and height H and the punching limit indentation depth. Figure 16 is a cross-sectional photograph of the metal sheet after processing and the results of elemental analysis of the end face. Figure 17 is a graph showing the relationship between the angle θ and height H and the plating remaining rate. Figure 18 is a photograph of the metal sheet before and after an atmospheric exposure test. Figure 19 is a cross-sectional photograph of the metal sheet after processing and the results of elemental analysis of the end face. Figure 20 is a graph showing the relationship between the angle θ and height H and the plating remaining rate. Figure 21 is a photograph of the metal sheet before and after an atmospheric exposure test.

[0015] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and the description thereof will not be repeated. The dimensional ratios between the components shown in each drawing do not necessarily represent the actual dimensional ratios.

[0016] [First Embodiment] [Processing Apparatus] Fig. 1 is a cross-sectional view schematically showing the configuration of a processing apparatus 20 according to a first embodiment of the present invention. The processing apparatus 20 is a mold used for shearing a metal plate. The processing apparatus 20 is particularly suitable for, but not limited to, shearing a metal plate having a plating layer on its surface (hereinafter sometimes referred to as a "surface-plated metal plate"). Shearing processes include, but are not limited to, drilling, punching, cutting, and the like.

[0017] The processing device 20 includes a punch 21, a die 22, and a plate holder 23. The punch 21 and the die 22 are arranged on one side and the other side in the plate thickness direction of the metal plate 10, which is the workpiece. The processing device 20 shears the metal plate 10 by moving at least one of the punch 21 and the die 22 in the plate thickness direction using a press machine (not shown) so that the punch 21 and the die 22 approach each other. The plate holder 23 is arranged to face the die 22 with the metal plate 10 sandwiched therebetween, and prevents the metal plate 10 from warping when the metal plate 10 is sheared and from biting into the punch 21 when the punch 21 is withdrawn.

[0018] Hereinafter, the direction parallel to the plate thickness direction may be referred to as the z direction, and the plane perpendicular to the z direction may be referred to as the xy plane. Also, the dimension in the plate thickness direction may be referred to as the "height."

[0019] The punch 21 has an end face 211 and a side face 212 that is continuous with the end face 211. Similarly, the die 22 has an end face 221 and a side face 222 that is continuous with the end face 221. The end face 211 comes into contact with the metal sheet 10 earlier than the side face 212 during processing, and the end face 221 comes into contact with the metal sheet 10 earlier than the side face 222 during processing.

[0020] The end faces 211 and 221 are preferably perpendicular to the thickness direction of the metal plate 10. In other words, the end faces 211 and 221 are preferably parallel to the metal plate 10.

[0021] A clearance CL of a predetermined size is provided between the contours of the end faces 211 and 221 in a plan view. As a result, the punch 21 and the die 22 are arranged so that the end faces 211 and 221 do not overlap in a plan view. Here, "plan view" means that the object is viewed straight from one side in the plate thickness direction. The end faces 211 and 221 "do not overlap in a plan view" means that the end faces 211 and 221 do not overlap when projected onto a plane (xy plane) perpendicular to the plate thickness direction.

[0022] According to this configuration, the punch 21 and the die 22 can be brought close to each other until the distance in the plate thickness direction between the end face 211 and the end face 221 becomes equal to or less than zero. This makes it possible to more reliably cut the metal plate 10. Furthermore, it is possible to prevent the punch 21 and the die 22 from colliding with each other when the metal plate 10 is cut.

[0023] The end faces 211 and 221 can have any shape as long as they do not overlap in a plan view. The planar shape of the end face 211 (shape in the xy plane) is, for example, circular, elliptical, rectangular, etc. The planar shape of the end face 221 is, for example, a shape with a circular hole, a shape with an elliptical hole, a shape with a rectangular hole, etc. It is preferable that the planar shape of the end face 221 is formed so that the clearance CL is constant.

[0024] The planar shape of the end face 211 is preferably circular. The planar shape of the end face 221 is preferably a shape with a circular hole. In the case of a circular shape, the material is constrained in the circumferential direction, so uniform deformation can be imparted. This makes it possible to impart excellent corrosion resistance to the end face when the surface-plated metal sheet is sheared.

[0025] The size (area) of the end face 211 is not particularly limited. However, if the end face 211 is too small, it may not be able to withstand the load during processing and may be broken. The size of the end face 211 is preferably equivalent to a circle with an outer diameter of 10 mm (area of ​​about 78 mm ２On the other hand, if the end face 211 is too large, the load required to press the metal plate 10 by the inclined portion 212a (described later) increases, which may require the use of a press machine with higher performance.

[0026] The punch 21 and the die 22 may be solid or hollow. The punch 21 and the die 22 are preferably solid. A compressive stress is applied to the punch 21 and the die 22 by the inclined portion 212a described below when the metal sheet 10 is pressed. Therefore, it is preferable that the punch 21 and the die 22 have a strength sufficient to withstand the stress.

[0027] The side surface 212 of the punch 21 is inclined so that the surface faces the metal plate 10 and includes an inclined portion 212a formed so as to overlap the die 22 in a plan view.

[0028] Here, "inclined so that the surface faces the metal plate 10" means that the normal line extending outward from the surface of the inclined portion 212a faces the metal plate 10. More specifically, when the side on which the punch 21 is located as viewed from the metal plate 10 is defined as the positive z direction and the side on which the die 22 is located is defined as the negative z direction, this means that the z direction component of the normal line extending outward from the surface of the inclined portion 212a is negative.

[0029] Furthermore, the phrase "overlaps in a plan view" of the inclined portion 212a with the die 22 means that when the inclined portion 212a and the die 22 are projected onto a plane (xy plane) perpendicular to the plate thickness direction, the inclined portion 212a and the die 22 overlap. In this case, it is not necessary for the entire inclined portion 212a to overlap with the die 22, and it is sufficient that at least a part of the inclined portion 212a overlaps with the die 22.

[0030] According to this configuration, when the punch 21 and the die 22 are brought close to each other, the metal sheet 10 is sandwiched between the inclined portion 212a and the die 22, and a compressive stress is applied to the metal sheet 10. This compressive stress causes the metal sheet 10 to deform into a specific shape, which will be described later.

[0031] The angle θ formed by the surface of the inclined portion 212a and the plate thickness direction is equal to or greater than 15°. The preferred range of the angle θ will be described later.

[0032] In relation to the thickness of the metal plate 10, the height HT of the inclined portion 212a is preferably 60% or more of the thickness of the metal plate 10. The height HT of the inclined portion 212a is preferably 1 mm or more, more preferably 3 mm or more, and even more preferably 5 mm or more.

[0033] The side surface 212 of the punch 21 includes, in addition to the inclined portion 212a, a tip portion 212b that is continuous with the inclined portion 212a, is formed at an end portion closer to the metal plate 10 in the plate thickness direction, and has a surface that is approximately parallel to the plate thickness direction. The angle formed between the surface of the tip portion 212b and the plate thickness direction is preferably 5.0° or less, preferably 3.0° or less, more preferably 1.0° or less, and even more preferably 0.5° or less.

[0034] The tip portion 212b allows a larger shear stress to be applied to the metal plate 10. This makes it possible to more reliably separate the metal plate 10. However, depending on the size of the clearance CL and the material of the metal plate 10, the metal plate 10 can be separated even without the tip portion 212b. Therefore, it is not essential that the side surface 212 includes the tip portion 212b, and the side surface 212 does not have to include the tip portion 212b.

[0035] Furthermore, the presence of the tip portion 212b clarifies the size of the clearance CL, allowing for more reliable alignment of the punch 21 and the die 22. The presence of the tip portion 212b allows for this effect to be achieved even if the height H of the tip portion 212b is small. In relation to the thickness of the metal sheet 10, the lower limit of the height H is preferably 1% of the thickness of the metal sheet 10, more preferably 2%, and even more preferably 3%. The lower limit of the height H is preferably 0.03 mm, more preferably 0.06 mm, and even more preferably 0.09 mm.

[0036] On the other hand, if the height H of the tip portion 212b is too large, the metal sheet 10 may be divided before the inclined portion 212a comes into contact with the metal sheet 10. Furthermore, the smaller the height H, the later the timing at which the metal sheet 10 is divided tends to be. As will be described in detail later, when a surface-plated metal sheet is sheared, the later the timing at which the metal sheet 10 is divided, the more excellent corrosion resistance can be imparted to the end face.

[0037] Therefore, from the viewpoint of imparting excellent corrosion resistance to the manufactured metal component, the smaller the height H of the tip portion 212b, the more preferable. In relation to the thickness of the metal plate 10, the upper limit of the height H is preferably 50% of the thickness of the metal plate 10, more preferably 40%, and even more preferably 30%. The upper limit of the height H is preferably 1.6 mm, more preferably 1.2 mm, and even more preferably 0.8 mm.

[0038] The side surface 222 of the die 22 is substantially parallel to the plate thickness direction. The side surface 222 of the die 22 does not include an inclined portion like the inclined portion 212 a of the side surface 212 of the punch 21 .

[0039] [Method for manufacturing a metal member] Next, a method for manufacturing a metal member according to this embodiment will be described. The method for manufacturing a metal member according to this embodiment includes a step of shearing a surface-plated metal sheet using a processing device 20.

[0040] The base material of the surface-plated metal sheet is, but is not limited to, steel, copper, copper alloy, aluminum, aluminum alloy, etc. The manufacturing method according to this embodiment is particularly suitable when the base material of the surface-plated metal sheet is steel, i.e., when the surface-plated metal sheet is a plated steel sheet. This is because steel is prone to rust, and the corrosion resistance imparted by this embodiment is a great advantage. The plated steel sheet is, for example, a Zn-based plated steel sheet, an Al-based plated steel sheet, etc.

[0041] The surface-plated metal sheet is more preferably a Zn-based plated steel sheet. Zn-based plating has a sacrificial corrosion protection effect on the base steel sheet. Therefore, it is possible to suppress corrosion from the exposed portion of the base material at the cut end surface due to shearing, and to further improve the corrosion resistance of the manufactured metal member. Examples of Zn-based plating include, but are not limited to, hot-dip galvannealing, galvannealed galvanizing, Zn—Ni-based plating, Zn—Al-based plating, Zn—Mg-based plating, and Zn—Al—Mg-based plating.

[0042] The thickness of the surface-plated metal sheet is preferably 0.2 to 9 mm. If the sheet thickness is too thick, the proportion of fractured surfaces after shearing may increase, which may reduce the effect of improving corrosion resistance. The upper limit of the sheet thickness of the surface-plated steel sheet is more preferably 6 mm. On the other hand, if the sheet thickness is sufficiently thin, rust generated on the edge surface is not noticeable, so the benefit of improving corrosion resistance is small. The lower limit of the sheet thickness of the surface-plated steel sheet is more preferably 1.0 mm.

[0043] The thickness of the plating layer of the surface-plated metal sheet is preferably 15 μm or more. If the plating layer is too thin, the plating layer that can cover the end surface may be depleted, and corrosion resistance may not be imparted to the end surface. The lower limit of the thickness of the plating layer of the surface-plated metal sheet is more preferably 30 μm. The upper limit of the thickness of the plating layer of the surface-plated metal sheet is not particularly limited, but is, for example, 150 μm.

[0044] 1 and 2 , a process for shearing a metal sheet 10 (surface-plated metal sheet) using a processing device 20 will be described. As described in the description of the configuration of the processing device 20, a punch 21 and a die 22 are disposed on one side and the other side of the metal sheet 10 in the thickness direction. At least one of the punch 21 and the die 22 is moved in the thickness direction by a press (not shown) so that the punch 21 and the die 22 approach each other. At this time, as shown in FIG. 2 , an inclined surface 111 is formed on the metal sheet 10 by the inclined portion 212a of the punch 21.

[0045] Thereafter, the punch 21 and the die 22 are brought closer to each other, thereby dividing the metal plate 10 into the first portion 11 and the second portion 12. At this time, a cut surface 112 is formed on the end face of the first portion 11, continuing from the inclined surface 111. The cut surface 112 includes a shear surface and a fracture surface. However, depending on the processing conditions, the cut surface 112 may be either a shear surface or a fracture surface, or the cut surface 112 may not be formed at all.

[0046] In this embodiment, the first portion 11 having the inclined surface 111 becomes the product (metal member). The inclined surface 111 is formed by deforming the surface of the metal sheet 10, which is a surface-plated metal sheet, and therefore has a plating layer on at least a portion thereof. Although the plating layer on the inclined surface 111 may be partially peeled off due to sliding with the punch 21, etc., the plating layer still remains to a greater extent on the inclined surface 111 than on the sheared surface or fractured surface. Furthermore, the thickness of the plating layer covering the inclined surface 111 is not significantly reduced from the thickness of the plating layer on the surface-plated metal sheet.

[0047] The shear surface may be covered with a plating layer because the plating layer on the surface of the metal plate 10 has spread over, but may not be covered with a plating layer. The fracture surface is usually not covered with a plating layer.

[0048] According to the processing apparatus 20 and the method for manufacturing a metal component according to this embodiment, the end face of the manufactured metal component includes an inclined surface, which increases the proportion of the end face covered with a plating layer, thereby obtaining a metal component with excellent corrosion resistance at the cut end face.

[0049] The angle θ ( FIG. 1 ) formed by the surface of the inclined portion 212a of the punch 21 and the thickness direction of the metal sheet 10 is 15° or greater. The larger the angle θ, the later the timing at which the metal sheet 10 is divided. "Delaying the timing at which the metal sheet 10 is divided" means that the punch 21 and the die 22 must approach each other to divide the metal sheet 10. The later the timing at which the metal sheet 10 is divided, the smaller the height of the cut surface 112 and the greater the ratio of the height of the inclined surface 111 to the thickness of the metal sheet 10. Therefore, the larger the angle θ, the greater the proportion of the end surface covered with the plating layer. The lower limit of the angle θ is preferably 20°, and more preferably 30°.

[0050] On the other hand, the larger the angle θ, the larger the load required to form the inclined surface 111. In addition, the angle θ coincides with the inclination angle of the inclined surface 111, and an increase in the angle θ means that the projection area of ​​the formed inclined surface 111 onto the xy plane increases. The upper limit of the angle θ is preferably 60°, more preferably 50°, and even more preferably 45°.

[0051] As described in the explanation of the configuration of the processing device 20, the smaller the height H of the tip 212b of the punch 21, the later the timing at which the metal sheet 10 is cut. The later the timing at which the metal sheet 10 is cut, the smaller the height of the cut surface 112, and the greater the ratio of the height of the inclined surface 111 to the thickness of the metal sheet 10. Therefore, the smaller the height H, the greater the ratio of the end surface covered with the plating layer can be.

[0052] [Metal member] As described above, in the method for manufacturing a metal member according to this embodiment, the first portion 11 in Fig. 2 becomes the product (metal member). The first portion 11 is the remaining portion after the second portion 12 is punched out from the metal plate 10. Hereinafter, the first portion 11 will be referred to as the metal member 11.

[0053] Fig. 3 is a perspective view of the metal member 11, and Fig. 4 is a cross-sectional view taken along line IV-IV in Fig. 3. Fig. 3 illustrates a case where the contour of the hole in the metal member 11 is circular, but this is an example. As described in the explanation of the configuration of the processing device 20, the end face 211 of the punch 21 and the end face 221 of the die 22 may have any planar shape. Therefore, the contour of the hole in the metal member 11 may also have any shape.

[0054] The metal member 11 has one inclined surface 111 on its end surface. The metal member 11 further has a cut surface 112 that is continuous with the inclined surface 111 and is formed at the end of the metal member 11 on the side where the dimension of the metal member 11 increases in the thickness direction due to the inclined surface 111. As shown in Fig. 4, the cut surface 112 includes a shear surface 112a whose surface is approximately parallel to the thickness direction, and a fracture surface 112b. The shear surface 112a and the fracture surface 112b are formed in this order from the side closest to the inclined surface 111.

[0055] The metal member 11 has its surfaces covered with a plating layer 10a except for its end faces. Of the end faces of the metal member 11, at least a portion of the inclined surface 111 is covered with the plating layer 10a. The sheared surface 112a may or may not be covered with the plating layer 10a. The fractured surface 112b is usually not covered with the plating layer 10a. Figure 4 illustrates, as an example, a case in which the entire inclined surface 111 and a portion of the sheared surface 112a are covered with the plating layer 10a, and the base material is exposed at the remaining portion of the sheared surface 112a and the fractured surface 112b.

[0056] The height Ht of the inclined surface 111 is 60% or more of the plate thickness T. The greater the ratio of the height Ht to the plate thickness T, the higher the corrosion resistance of the end face. The lower limit of the height Ht is preferably 70% of the plate thickness T, more preferably 80%, and even more preferably 90%. To increase the height Ht of the inclined surface 111, for example, the angle θ between the surface of the inclined portion 212a of the punch 21 (FIG. 1) and the plate thickness direction may be increased, or the height H of the tip portion 212b of the punch 21 may be reduced.

[0057] The entire end face of the metal member 11 may be an inclined surface 111. In other words, the metal member 11 does not have to have a cut surface 112. On the other hand, if the metal member 11 has a cut surface 112, the metal member 11 can be manufactured more stably. The lower limit of the height of the cut surface 112 is preferably 3% of the plate thickness T, and more preferably 5%.

[0058] Even if a portion of the cut surface 112 is not covered with the plating layer 10a, the metal member 11 has good corrosion resistance because at least a portion of the inclined surface 111 is covered with the plating layer 10a. In particular, when the surface-plated metal sheet is a Zn-based plated steel sheet, the Zn-based plated layer has a sacrificial corrosion protection effect on the base steel sheet, so corrosion resistance can be ensured even if a certain proportion of the base material is exposed.

[0059] The angle θ between the inclined surface 111 and the plate thickness direction is 15° or more. The lower limit of the angle θ is preferably 20°, more preferably 30°. The upper limit of the angle θ is preferably 60°, more preferably 50°, and even more preferably 45°.

[0060] The angle θ formed by the inclined surface 111 and the thickness direction of the sheet can be controlled by the shape of the punch 21 (FIG. 1). The angle θ formed by the inclined surface 111 and the thickness direction of the sheet coincides with the angle θ formed by the inclined portion 212a and the thickness direction of the sheet.

[0061] The plating layer 10a covering at least a portion of the inclined surface 111 is derived from the workpiece material, and therefore has exactly the same components as the plating layer 10a covering the surface other than the end face.

[0062] The proportion of the area of ​​the inclined surface 111 that is covered with the plating layer 10a is preferably 60% or more, and it is more preferable that the entire inclined surface 111 be covered with the plating layer 10a.

[0063] The thickness of the plating layer 10a covering the inclined surface 111a is preferably 25 to 90% of the thickness of the plating layer 10a covering the surfaces other than the end faces.

[0064] 4 illustrates a case in which an inclined surface 111 and a cut surface 112 are formed on the end surface of the metal member, and the cut surface 112 includes a shear surface 112a and a fracture surface 112b, but the cut surface 112 does not necessarily include either the shear surface 112a or the fracture surface 112b. Also, as described above, the metal member 11 does not necessarily have to have a cut surface 112.

[0065] The above has described the processing device 20, the method for manufacturing a metal member, and the metal member 11 according to the first embodiment of the present invention. According to this embodiment, a metal member having excellent corrosion resistance at the cut end surface can be obtained.

[0066] [Second embodiment] [Processing apparatus] Figure 5 is a cross-sectional view schematically showing the configuration of a processing apparatus 30 according to a second embodiment of the present invention. The processing apparatus 30 differs from the processing apparatus 20 (Figure 1) according to the first embodiment in the configuration of the punch and die. The processing apparatus 30 includes a punch 31 instead of the punch 21 of the processing apparatus 20, and a die 32 instead of the die 22 of the processing apparatus 20.

[0067] The punch 31 has an end face 311 and a side face 312 that is continuous with the end face 311. Similarly, the die 32 has an end face 321 and a side face 322 that is continuous with the end face 321. In this embodiment as well, a clearance CL of a predetermined size is provided between the contours of the end faces 311 and 321 in a plan view. As a result, the punch 31 and the die 32 are positioned so that the end faces 311 and 321 do not overlap in a plan view.

[0068] The side surface 312 of the punch 31 is substantially parallel to the thickness direction of the plate.

[0069] The side surface 322 of the die 32 is inclined so that the surface faces the metal plate 10 and includes an inclined portion 322a formed so as to overlap the punch 31 in a plan view.

[0070] Here, "inclined so that the surface faces the metal plate 10" means, more specifically, that when the side on which the punch 31 is located is viewed from the metal plate 10 as being positive in the z direction and the side on which the die 32 is located as being negative in the z direction, the z direction component of the normal extending outward from the surface of the inclined portion 322a is positive.

[0071] Furthermore, the phrase "overlaps in a plan view" of the inclined portion 322a with the punch 31 means that when the inclined portion 322a and the punch 31 are projected onto a plane (xy plane) perpendicular to the plate thickness direction, the inclined portion 322a and the punch 31 overlap. In this case, it is not necessary for the entire inclined portion 322a to overlap with the punch 31; it is sufficient that at least a portion of the inclined portion 322a overlaps with the punch 31.

[0072] With this configuration, when the punch 31 and the die 32 are brought close to each other, the metal sheet 10 is sandwiched between the inclined portion 322a and the punch 31, and compressive stress is applied to the metal sheet 10. This compressive stress causes the metal sheet 10 to deform into a specific shape.

[0073] The angle θ formed between the surface of the inclined portion 322a and the plate thickness direction, and the height HT of the inclined portion 322a are the same as those in the first embodiment.

[0074] The side surface 322 of the die 32 includes an inclined portion 322a and a tip portion 322b that is continuous with the inclined portion 322a, is formed at an end closer to the metal plate 10 in the plate thickness direction, and has a surface that is approximately parallel to the plate thickness direction. The height H of the tip portion 322b is the same as in the first embodiment. Also, as in the first embodiment, the side surface 322 does not have to include the tip portion 322b.

[0075] [Method for manufacturing a metal member] Next, a method for manufacturing a metal member according to this embodiment will be described. The method for manufacturing a metal member according to this embodiment includes a step of shearing a surface-plated metal sheet using a processing device 30.

[0076] 5 and 6 , a process for shearing a metal sheet 10 (surface-plated metal sheet) using a processing device 30 will be described. A punch 31 and a die 32 are placed on one side and the other side of the metal sheet 10 in the thickness direction. At least one of the punch 31 and the die 32 is moved in the thickness direction by a press (not shown) so that the punch 31 and the die 32 approach each other. At this time, as shown in FIG. 6 , an inclined surface 141 is formed on the metal sheet 10 by the inclined portion 322a of the die 32.

[0077] Thereafter, the punch 31 and the die 32 are brought closer to each other, thereby dividing the metal plate 10 into the first portion 13 and the second portion 14. At this time, a cut surface 142 is formed on the end face of the second portion 14, continuing from the inclined surface 141. The cut surface 142 includes a shear surface and a fracture surface. However, depending on the processing conditions, the cut surface 142 may be only one of the shear surface and the fracture surface, or the cut surface 142 may not be formed at all.

[0078] In this embodiment, the second portion 14 is the product (metal member).

[0079] According to the processing apparatus 30 and the method for manufacturing a metal component according to this embodiment, the end face of the manufactured metal component includes the inclined surface 141, so that the proportion of the end face covered with the plating layer can be increased. This makes it possible to obtain a metal component with excellent corrosion resistance at the cut end face.

[0080] [Metal Member] As described above, in the method for manufacturing a metal member according to this embodiment, the second portion 14 in Fig. 6 becomes the product (metal member). The second portion 14 is a portion punched out from the metal plate 10. Hereinafter, the second portion 14 will be referred to as the metal member 14.

[0081] Fig. 7 is a perspective view of the metal member 14, and Fig. 8 is a cross-sectional view taken along line VIII-VIII in Fig. 7. Fig. 7 illustrates a case where the outline of the metal member 14 is circular, but this is an example. The outline of the metal member 14 may have any shape.

[0082] The metal member 14 has one inclined surface 141 on its end surface. The metal member 14 further has a cut surface 142 that is continuous with the inclined surface 141 and is formed at the end of the metal member 14 on the side where the dimension of the metal member 14 increases in the thickness direction due to the inclined surface 141. As shown in Fig. 8 , the cut surface 142 includes a shear surface 142a whose surface is approximately parallel to the thickness direction, and a fracture surface 142b. The shear surface 142a and the fracture surface 142b are formed in this order from the side closest to the inclined surface 141.

[0083] Similar to the metal member 11 ( FIG. 4 ), the metal member 14 has its surfaces covered with a plating layer 10a except for its end faces. Of the end faces of the metal member 14, at least a portion of the inclined surface 141 is covered with the plating layer 10a. The sheared surface 142a may or may not be covered with the plating layer 10a. The fractured surface 142b is usually not covered with the plating layer 10a. FIG. 8 illustrates, as an example, a case in which the entire inclined surface 141 and a portion of the sheared surface 142a are covered with the plating layer 10a, and the base material is exposed at the remaining portion of the sheared surface 142a and the fractured surface 142b.

[0084] The height Ht of the inclined surface 141, the height of the cut surface 142, the angle θ between the inclined surface 141 and the plate thickness direction, etc. are the same as in the first embodiment. The height Ht of the inclined surface 141, the height of the cut surface 142, and the angle θ between the inclined surface 141 and the plate thickness direction can be controlled by the shape of the die 32 ( FIG. 5 ). Also, as in the first embodiment, the cut surface 142 does not have to include either the shear surface 142 a or the fracture surface 142 b, and the metal member 14 does not have to have the cut surface 142.

[0085] The processing apparatus 30, the method for manufacturing a metal member, and the metal member 14 according to the second embodiment of the present invention have been described above. In the processing apparatus 20 ( FIG. 1 ) according to the first embodiment, the side surface 212 of the punch 21 is provided with an inclined portion 212a, whereas in the processing apparatus 30 ( FIG. 5 ) according to the second embodiment, the side surface 322 of the die 32 is provided with an inclined portion 322a. In the first embodiment, the inclined surface 111 is formed in the first portion 11 ( FIG. 2 ), whereas in the second embodiment, the inclined surface 141 is formed in the second portion 14 ( FIG. 6 ). However, in either case, the same effect can be obtained with respect to corrosion resistance of the end face.

[0086] That is, in order to manufacture a metal component having an end face with excellent corrosion resistance, it is sufficient that at least one of the side faces of the punch and the die includes an inclined portion, the inclined portion being inclined so that the surface faces the metal sheet and overlaps the other of the punch and the die in a plan view.

[0087] [Third Embodiment] Figure 9 is a cross-sectional view schematically showing the configuration of a processing apparatus 40 according to a third embodiment of the present invention. The processing apparatus 40 differs from the processing apparatus 20 according to the first embodiment (Figure 1) in the configuration of the die. The processing apparatus 40 includes a die 32 instead of the die 22 of the processing apparatus 20. The die 32 is the same as that of the processing apparatus 30 according to the second embodiment (Figure 5).

[0088] In this embodiment as well, a clearance CL of a predetermined size is provided in a plan view between the contour of the end face of the punch 21 and the contour of the end face of the die 32. This allows the punch 21 and the die 32 to be positioned so that their end faces do not overlap in a plan view.

[0089] In this embodiment, an inclined portion is provided on both the side surface of the punch 21 and the side surface of the die 32. As shown in Fig. 10, the metal plate 10 is divided into a first portion 11 having an inclined surface 111 and a second portion 14 having an inclined surface 141. In this embodiment, both the first portion 11 and the second portion 14 become products (metal members).

[0090] The processing apparatus, the method for manufacturing a metal member, and the metal member according to the third embodiment of the present invention have been described above. This embodiment also makes it possible to obtain a metal member having excellent corrosion resistance at the cut end surface.

[0091] [Fourth embodiment] [Processing apparatus] Figure 11 is a cross-sectional view showing a schematic configuration of a processing apparatus 50 according to a fourth embodiment of the present invention. The processing apparatus 50 differs from the processing apparatus 20 (Figure 1) according to the first embodiment in the configuration of the punch and die. The processing apparatus 50 includes a punch 51 instead of the punch 21 of the processing apparatus 20, and a die 52 instead of the die 22 of the processing apparatus 20.

[0092] The punch 51 has an end face 511 and a side face 512 that is continuous with the end face 511. Similarly, the die 52 has an end face 521 and a side face 522 that is continuous with the end face 521. A clearance CL of a predetermined size is provided between the contours of the end faces 511 and 521 in a plan view. This allows the punch 51 and the die 52 to be positioned so that their end faces do not overlap in a plan view.

[0093] The side surface 512 of the punch 51 includes an inclined portion 512a and a tip portion 512b, as in the first embodiment. The side surface 522 of the die 52 is substantially parallel to the thickness direction of the plate.

[0094] The punch 51 and die 52 of the processing device 50 and the punch 21 and die 22 of the processing device 20 (FIG. 1) have different planar shapes.

[0095] 12 is a perspective view of a metal member 15 manufactured by the processing device 50. The metal member 15 is obtained by cutting a metal plate along one of the directions (y direction) perpendicular to the plate thickness direction. The metal member 15 has an inclined surface 151 and a cut surface 152.

[0096] The inclined surface 151 and the cut surface 152 are similar to the inclined surface 111 and the cut surface 112 of the metal member 11 (FIG. 3) except for their planar shapes (shapes in the xy plane). Therefore, according to this embodiment, a metal member having excellent corrosion resistance at the cut end surfaces can also be obtained.

[0097] 3 and 4 illustrate examples in which the manufactured metal component is the remaining portion after a predetermined shape has been punched out of a metal plate (FIG. 3), and the portion punched out of the metal plate (FIG. 7). In addition, even when the metal component is obtained by cutting a metal plate, as in this embodiment, the same effects as those of the previously described embodiment can be obtained. Note that the line along which the metal plate 10 is cut does not have to be a straight line.

[0098] In the above embodiment, a case has been described in which an inclined portion 512a is formed on the side surface 512 of the punch 51, but instead of or in addition to the side surface 512 of the punch 51, the side surface 522 of the die 52 may include an inclined portion.

[0099] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0100] A metal plate was punched using a processing device similar to the configuration of the processing device 20 (Fig. 1). The shape of the end face 211 of the punch 21 was a circle with a diameter of 10.0 mm, and the clearance CL was 0.05 mm (the diameter of the hole in the die 22 was 10.1 mm). Prototypes were made by changing the angle θ to 15°, 30°, and 45°, and the height H to 0.1 mm, 0.4 mm, and 0.8 mm. The workpiece had a yield strength of 366 MPa, a tensile strength of 454 MPa, an elongation of 31%, a plate thickness of 3.2 mm, and a coating weight of 275 g / m. ２ The Zn-Al-Mg plated steel sheet was

[0101] As a comparative example, a metal plate was punched using a cylindrical punch having a diameter of 10.0 mm and a die having a cylindrical hole having a diameter of 10.8 mm.

[0102] Fig. 13 is a contour map showing the stress distribution in the metal plate during processing, calculated by the finite element method. As shown in Fig. 13, in the processing device of the embodiment, the area pressed by the inclined portion becomes highly stressed, and a stress concentration area occurs from the shoulder of the die parallel to the inclined portion.

[0103] Fig. 14 is a photograph of the cross section of the metal plate immediately before fracture. From Fig. 14, it can be seen that when processed using the processing device of the example, the timing at which cracks occurred was later than when processed using the processing device of the comparative example (i.e., cracks did not occur unless the punch was pressed deeper).

[0104] Fig. 15 is a graph showing the relationship between the angle θ and the height H and the punching limit indentation depth. The punching limit indentation depth is the indentation depth of the punch just before the metal plate breaks, and the larger the punching limit indentation depth, the later the timing at which the metal plate breaks. From Fig. 15, it can be seen that the larger the angle θ and the smaller the height H, the larger the punching limit indentation depth.

[0105] Figure 16 shows a cross-sectional photograph of the processed metal sheet and the results of elemental analysis of the edge surface. "Hp" in Figure 16 refers to the height of the edge surface where the plating layer remains (hereinafter referred to as "residual plating height Hp"). The residual plating height Hp was determined by measuring the edge surface of the metal sheet using an energy dispersive X-ray analyzer (EDX) and examining the distribution of Zn and Fe on the edge surface. In the metal sheet processed with a punch whose inclined portion angle θ was 30°, there were areas where the plating layer had peeled off near the bottom of the inclined surface. In the metal sheet processed with a punch whose inclined portion angle θ was 45°, the plating layer remained, albeit intermittently, all the way to the bottom of the inclined surface.

[0106] Fig. 17 is a graph showing the relationship between the angle θ and the height H and the plating residual rate. The plating residual rate is the value obtained by dividing the plating residual height Hp by the plate thickness. Fig. 17 shows that the plating residual rate tends to increase as the angle θ increases and as the height H decreases. The plating residual rate of the metal plate processed using the processing device of the comparative example was a maximum of 20%.

[0107] Figure 18 shows photographs of the metal plate before and after the atmospheric exposure test. The atmospheric exposure test was performed by cutting the metal plate in half, applying an anti-rust paint to the end surfaces other than the evaluation surface (the end surface formed by punching), and then placing the metal plate outdoors. The metal plate processed using the processing device of the comparative example had a large and noticeable area of ​​red rust on the fracture surface three weeks after the start of exposure. In contrast, the metal plate processed using the processing device of the example showed slight red rust three weeks after the start of exposure when the height H was 0.4 mm, and eight weeks after the start of exposure when the height H was 0.1 mm, but the area was small and difficult to see visually.

[0108] Next, a processing device similar in configuration to the processing device 50 ( FIG. 11 ) was used to perform shearing, cutting a metal plate into a straight line. The clearance CL between the end face 511 of the punch 51 and the end face 521 of the die 52 was set to 0.05 mm. Prototypes were made by varying the angle θ to 15°, 30°, and 45°, and the height H to 0.1 mm, 0.4 mm, and 0.8 mm. The workpiece was the same Zn—Al—Mg-plated steel sheet as used in the punching process. As a comparative example, a shearing die with vertical sides (clearance 0.4 mm) was used to perform shearing, cutting a metal plate into a straight line.

[0109] 19 shows a cross-sectional photograph of the processed metal sheet and the results of elemental analysis of the end surface. In the metal sheet processed with a punch having an inclined portion with an angle θ of 45°, the plating layer remained all the way to the bottom of the inclined surface.

[0110] 20 is a graph showing the relationship between the angle θ and the height H and the plating remaining rate. The plating remaining rate of the metal sheet processed by the processing device of the comparative example was 18% at most.

[0111] 21 shows photographs of the metal plate before and after the atmospheric exposure test. The metal plate processed using the processing device of the comparative example had red rust on the fracture surface six weeks after the start of exposure. In contrast, the metal plate processed using the processing device of the example did not have red rust six weeks after the start of exposure.

[0112] Although the embodiments of the present invention have been described above, the above-described embodiments are merely examples for carrying out the present invention. Therefore, the present invention is not limited to the above-described embodiments, and the above-described embodiments can be appropriately modified and carried out within the scope of the invention.

[0113] REFERENCE SIGNS LIST 10 Metal plate 11 First portion (metal member) 111 Inclined surface 112 Cut surface 112a Shear surface 112b Fracture surface 12 Second portion 13 First portion 14 Second portion (metal member) 141 Inclined surface 142 Cut surface 142a Shear surface 142b Fracture surface 15 Metal member 20, 30, 40, 50 Processing device 21, 31, 51 Punch 211, 311, 511 End surface 212, 312, 512 Side surface 212a, 512a Inclined portion 212b, 512b Tip portion 22, 32, 52 Die 221, 321, 521 End surface 222, 322, 522 Side surface 322a Inclined portion 322b Tip portion

Claims

DEPCT671. A processing machine comprising a punching section and a die is positioned on one side and the other side of a workpiece made of sheet metal, one side and the other side aligned in the sheet thickness direction. The processing machine is adjusted to shear the sheet metal by moving at least one of the punching sections and the die in the sheet thickness direction in such a way that the punching sections and the die are positioned close together, such that: each punching section and die includes end and side faces; the punching sections and the die are positioned in such a way that the end face of the punching section and the end face of the die do not overlap in the top view; at least one of the side faces of the punching section and the side face of the die includes an inclined section which provides a beveled surface facing the sheet metal and thus overlaps with one of the punching sections and the die in the top view; and the surfaces provided by the inclined section and the sheet thickness direction form an angle of not less than 15 degrees.2.

1. The processing machine under claim 1, where at least one of the side surfaces of the impact part and the side surfaces of the die, including, apart from the bevel, the end continuous with the bevel and positioned at an end closest to the sheet metal as specified in the sheet thickness direction and which are provided with a surface generally parallel to the sheet thickness direction.

3. The processing machine under claim 2, where the dimensions of the end, as measured in the sheet thickness direction, are not more than 50 percent of the sheet thickness of the sheet metal.

4. Any of the processing machines under claims 1 to 3, where the surfaces provided by the bevel and in the sheet thickness direction form an angle of 15 to 60 degrees.

5. The method of manufacturing metal components which involves the use of any of the processing machines under claims 1 to 3 to shear a sheet metal with a surface coating.

6. The method of manufacturing metal components under claim 5, where the sheet metal with a surface coating is coated steel.

7. The method of manufacturing metal components under claim 6, where the coating is a Zn-based coating. 8.

9. A metal assembly formed from sheet metal with a surface coating, where the edge surface, including one beveled surface, has dimensions in the sheet thickness direction of not less than 60 percent of the sheet thickness, the beveled surface and the sheet thickness direction forming an angle of not less than 15 degrees, and at least part of the beveled surface is covered by the surface coating.

10. A metal assembly under claim 8, where the edge surface, including the beveled surface, is formed by shearing an assembly made of sheet metal with a surface coating, and the surface coating covering at least part of the beveled surface is obtained from this assembly.

11. A metal assembly under claim 8 or 9, which is further incorporated with a cutting surface continuous with the beveled surface and positioned at one end of the metal assembly as specified in the sheet thickness direction, where the dimensions of the assembly are increased by the beveled surface, and which include at least one shear surface and fracture surface.Metal components under claim 10, where: the cutting surfaces include both shear and fracture surfaces; and the fracture surfaces are not covered by a plating layer.

12. Metal components under claim 8 or 9, where the metal sheet on which the plating layer is applied is plated steel sheet.

13. Metal components under claim 12, where the plating layer is a Zn-based plating layer.

Images