Manufacturing method of metal products

Abstract

To strike a balance between suppression of boring a hole in a wall surface of a tubular member and suppression of short of strength in a welded part when welding a thick plate-like member to a thin tubular member.SOLUTION: A method for manufacturing a metal product includes: a preparation step of preparing an assembly in which an end of a tubular member is inserted into a through-hole of a plate-like member and an additional member is inserted into the end of the tubular member; a welding step of welding the tubular member to the plate-like member of the assembly; and a removal step of removing at least part of the additional member from the assembly after the welding step.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a method for manufacturing a metal product. [Background technology]

[0002] Patent Document 1 discloses a method in which an end of a tubular member is inserted into a through hole of a plate-like member, and the plate-like member and the tubular member are welded together. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-248190 A Summary of the Invention [Problem to be solved by the invention]

[0004] When welding a thick plate-like member and a thin tubular member, the amount of heat input to the tubular member may be too large, causing holes in the wall of the tubular member. If the amount of heat input to the tubular member is reduced to prevent holes from being formed in the wall of the tubular member, the penetration depth may be insufficient, causing insufficient strength of the welded portion. Therefore, when welding a thick plate-like member and a thin tubular member, it is desirable to simultaneously prevent holes from being formed in the wall of the tubular member and prevent insufficient strength of the welded portion. [Means for solving the problem]

[0005] The present disclosure can be realized in the following forms.

[0006] (1) According to one aspect of the present disclosure, there is provided a method for manufacturing a metal product, the method for manufacturing a metal product comprising: a preparation step of preparing an assembly in which an end of a tubular member is inserted into a through hole of a plate-like member and an additional member is inserted into the end of the tubular member, a welding step of welding the tubular member and the plate-like member of the assembly together, and a removal step of removing at least a portion of the additional member from the assembly after the welding step. According to this embodiment of the joining method, the heat applied to the tubular member in the welding process can be dispersed to the additional member, so that even when welding a thick plate-like member to a thin tubular member, it is possible to simultaneously prevent holes from being generated in the wall surface of the tubular member and prevent a lack of strength in the welded portion. (2) In the manufacturing method of a metal product of the above aspect, a volume of an overlapping portion of the additional member and the tubular member in the assembly may be larger than a volume of an overlapping portion of the tubular member and the additional member in the assembly. According to this form of manufacturing method for a metal product, the heat applied to the tubular member in the welding process can be effectively dispersed to the additional member. (3) In the method for manufacturing a metal product according to the above aspect, the additional member may be a columnar body, and a through hole may be formed in the additional member in the removing step. According to this form of manufacturing method for a metal product, the heat applied to the tubular member in the welding process can be effectively dispersed to the additional member. (4) In the method for manufacturing a metal product according to the above aspect, the additional member may be a cylindrical body, and the removing step may enlarge an inner diameter of the additional member. According to this aspect of the method for manufacturing a metal product, the additional member can be easily removed in the removing step. The present disclosure may be realized in various forms other than the manufacturing method of a metal product, for example, in the form of a joining method, a welding method, or the like. [Brief description of the drawings]

[0007] [Figure 1] 1 is a flowchart showing the contents of a manufacturing method for a metal product. [Diagram 2] FIG. [Diagram 3] FIG. [Figure 4] FIG. [Diagram 5] 1 is a cross-sectional view of a metal product manufactured by a method for manufacturing a metal product. [Figure 6] FIG. 1 is a perspective view of a flanged pipe-like member as an example of a metal product. [Figure 7] FIG. 1 is a perspective view of a shell-and-tube heat exchanger as an example of a metal product. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] A. First embodiment: Fig. 1 is a flow chart showing the details of a method for manufacturing a metal product in a first embodiment. Fig. 2 is a cross-sectional view showing a preparation step of the manufacturing method. Fig. 3 is a cross-sectional view showing a welding step of the manufacturing method. Fig. 4 is a cross-sectional view showing a removal step of the manufacturing method. Fig. 5 is a cross-sectional view of a metal product manufactured by the manufacturing method.

[0009] First, in the preparation step of step S10 in FIG. 1, as shown in FIG. 2, an assembly 50 including a plate-shaped member 10, a tubular member 20, and an additional member 30 is prepared, in which an end of the tubular member 20 is inserted into the inside of the through hole 15 of the plate-shaped member 10, and the additional member 30 is inserted into the inside of the end of the tubular member 20. In this embodiment, in the preparation step, the end of the tubular member 20 is inserted into the inside of the through hole 15 of the plate-shaped member 10, and the additional member 30 is inserted into the inside of the end of the tubular member 20, thereby assembling the assembly 50. Therefore, in this embodiment, the preparation step includes assembling the assembly 50. Note that the assembly 50 may be prepared by carrying in an assembled assembly 50 in the preparation step. In this case, the preparation step does not include assembling the assembly 50.

[0010] In this embodiment, the shape of the through hole 15 of the plate-like member 10 is circular, and the cross-sectional shape of the tubular member 20 is annular. The outer diameter of the tubular member 20 is equal to the diameter of the through hole 15 of the plate-like member 10. The plate thickness t2 of the tubular member 20 is smaller than the plate thickness t1 of the plate-like member 10. The additional member 30 is a cylindrical body, and the outer diameter of the additional member 30 is equal to the inner diameter of the tubular member 20. The plate thickness t3 of the additional member 30 is larger than the plate thickness t2 of the tubular member 20. Each of the members 10, 20, and 30 is formed of a metal material such as stainless steel, aluminum alloy, or copper alloy. The materials of each of the members 10, 20, and 30 are the same.

[0011] The plate-like member 10 and the tubular member 20 of the assembly 50 are fixed, for example, to a jig not shown, and the additional member 30 of the assembly 50 is press-fitted and fixed, for example, to the tubular member 20. The outer wall surface of the tubular member 20 is in contact with the inner wall surface of the through hole 15 of the plate-like member 10 of the assembly 50, and the outer wall surface of the additional member 30 is in contact with the inner wall surface of the tubular member 20 of the assembly 50. In FIG. 2, an overlapping region RL where the tubular member 20 and the additional member 30 overlap in the assembly 50 is shown by a dashed line. The volume of an overlapping portion PL3 of the additional member 30 with the tubular member 20 in the assembly 50 is larger than the volume of an overlapping portion PL2 of the tubular member 20 with the additional member 30 in the assembly 50.

[0012] Next, in the welding process of step S20, the plate-shaped member 10 and the tubular member 20 of the assembly 50 are welded. As shown in FIG. 3, in this embodiment, the plate-shaped member 10 and the tubular member 20 are welded by TIG welding. More specifically, the welding torch WT is rotated around the end face of the tubular member 20 while an arc is generated between the welding torch WT and the end face of the tubular member 20, thereby welding the plate-shaped member 10 and the tubular member 20 so as to form an annular welded portion 40. It is preferable that the penetration depth H is equal to or less than the axial length of the additional member 30. Since the outer wall surface of the additional member 30 is in contact with the inner wall surface of the tubular member 20, the heat applied to the tubular member 20 during welding is transferred to the additional member 30 through the contact surface. Therefore, the plate-shaped member 10 and the tubular member 20 are welded, and the additional member 30 is also welded to the tubular member 20. Note that instead of welding the plate-shaped member 10 and the tubular member 20 to form an annular welded portion 40, the plate-shaped member 10 and the tubular member 20 may be welded to form a plurality of dot-like welded portions 40. The welding method is not limited to TIG welding, and may be, for example, laser welding.

[0013] Thereafter, in the removal process of step S30, at least a part of the additional member 30 is removed. As shown in Fig. 4, in this embodiment, in the removal process, the inner diameter of the additional member 30 is enlarged by removing the inner peripheral portion of the additional member 30 using a cutting tool TL. As shown in Fig. 5, in this embodiment, the inner peripheral portion of the additional member 30 is removed from the assembly 50, but the outer peripheral portion of the additional member 30 is left in the assembly 50. After the removal process, the manufacturing method for the metal product is completed, and the assembly 50 after the removal process becomes the metal product. Note that the entire additional member 30 may be removed from the assembly 50 in the removal process.

[0014] 6 is a perspective view of a flanged pipe-like component 100 as an example of a metal product manufactured by the above-mentioned manufacturing method. The flanged pipe-like component 100 has a flange portion 110 formed of a plate-like member 10 and a pipe portion 120 formed of a tubular member 20. A fluid flows inside the pipe portion 120.

[0015] FIG. 7 is a perspective view of a shell-and-tube type heat exchanger 200 as an example of a metal product manufactured by the above manufacturing method. The heat exchanger 200 has two flange portions 210, a plurality of tube portions 220, and a shell portion 230. In FIG. 7, a part of the shell portion 230 is cut out to show each tube portion 220 disposed inside the shell portion 230. A fluid flows through each tube portion 220. The heat exchanger 200 can be manufactured using the same number of plate-like members 10 as the number of flange portions 210, the same number of tubular members 20 as the number of tube portions 220, the number of additional members 30 as twice the number of tube portions 220, and a member for constituting the shell portion 230.

[0016] According to the manufacturing method of the metal product in the present embodiment described above, since the additional member 30 is in contact with the tubular member 20 in the welding process, the heat applied to the tubular member 20 during welding of the plate-shaped member 10 and the tubular member 20 is dispersed to the additional member 30 by heat conduction through the contact surface. In other words, the members that bear the heat applied to the tubular member 20 are not only the tubular member 20 but also the tubular member 20 and the additional member 30, so that the heat capacity of the members that bear the heat applied to the tubular member 20 is increased. As a result, the difference between the melting degree of the thick plate-shaped member 10 and the melting degree of the thin tubular member 20 is reduced. Therefore, it is possible to suppress the formation of holes in the wall surface of the tubular member 20 due to an excessive amount of heat input to the tubular member 20 in order to sufficiently melt the plate-shaped member 10, and it is possible to suppress the formation of holes in the wall surface of the tubular member 20 due to an insufficient amount of heat input to the plate-shaped member 10, which causes insufficient strength of the welded portion 40. Therefore, even when welding a thick plate-like member 10 and a thin tubular member 20, it is possible to both prevent holes from being formed in the wall of the tubular member 20 and prevent insufficient strength of the welded portion 40.

[0017] Furthermore, in this embodiment, since it is possible to prevent holes from forming in the wall surface of the tubular member 20 and prevent insufficient strength of the welded portion 40 without the need for a skilled worker to perform the welding process, the welding process can be automated using a welding robot.

[0018] Furthermore, in this embodiment, the volume of the overlapping portion PL3 of the additional member 30 with the tubular member 20 in the assembly 50 is larger than the volume of the overlapping portion PL2 of the tubular member 20 with the additional member 30 in the assembly 50, so that the heat applied to the tubular member 20 in the welding process can be effectively distributed to the additional member 30.

[0019] In addition, in this embodiment, in the removal step after the welding step, the portion of the additional member 30 that is no longer needed is removed. Therefore, it is possible to prevent the flow of fluid in the tubular member 20 from being obstructed by the additional member 30 when the metal product is used. Furthermore, in this embodiment, the additional member 30 is a cylindrical body, and the inner diameter of the additional member 30 is expanded in the removal step, thereby removing the portion of the additional member 30 that is no longer needed. Therefore, in the removal step, the additional member 30 can be easily removed while preventing damage to the tubular member 20.

[0020] In this embodiment, since the plate thickness t2 of the tubular member 20 can be reduced, when manufacturing a metal product in which a plurality of tubular members 20 are arranged in parallel, such as the heat exchanger 200 shown in FIG. 7, the tubular members 20 can be arranged densely, that is, the center distance between adjacent tubular members 20 can be shortened. In addition, since the additional member 30 is inserted into each tubular member 20, even if the heat when welding one of the adjacent tubular members 20 to the plate-like member 10 is transferred to the other tubular member 20, it is possible to suppress the formation of a hole in the wall surface of the other tubular member 20. Furthermore, even if the opening of the other tubular member 20 is blocked by the welded portion 40 formed when welding one of the adjacent tubular members 20 to the plate-like member 10, the unnecessary portion of the welded portion 40 blocking the opening of the tubular member 20 can be removed together with the unnecessary portion of the additional member 30 in the removal process, so that the occurrence of defective products can be suppressed without precise welding.

[0021] B. Other embodiments: (B1) In the manufacturing method for a metal product of the first embodiment described above, the volume of the overlapping portion PL3 of the additional member 30 with the tubular member 20 in the assembly 50 is larger than the volume of the overlapping portion PL2 of the tubular member 20 with the additional member 30 in the assembly 50. In contrast, the volume of the overlapping portion PL3 of the additional member 30 with the tubular member 20 in the assembly 50 may be equal to or smaller than the volume of the overlapping portion PL2 of the tubular member 20 with the additional member 30 in the assembly 50. In other words, the plate thickness t3 of the additional member 30 may be equal to or smaller than the plate thickness t2 of the tubular member 20. Even in this case, the heat applied to the tubular member 20 in the welding process can be dispersed to the additional member 30.

[0022] (B2) In the manufacturing method of a metal product of the first embodiment described above, the additional member 30 is a cylindrical body. Alternatively, the additional member 30 may be a columnar body. In this case, in the removing step, instead of enlarging the inner diameter of the additional member 30, a through hole along the central axis of the additional member 30 may be formed in the additional member 30. In this case, the volume of the overlapping portion PL3 of the additional member 30 with the tubular member 20 can be made larger than in a case where the additional member 30 is a cylindrical body, so that the heat applied to the tubular member 20 in the welding step can be effectively dispersed to the additional member 30.

[0023] (B3) In the manufacturing method of a metal product of the first embodiment described above, the cross-sectional shape of the tubular member 20 is a circular ring shape. In contrast, the cross-sectional shape of the tubular member 20 may be, for example, an oval shape. In this case, it is preferable that the shape of the through hole 15 of the plate-like member 10 and the shape of the additional member 30 are made to match the cross-sectional shape of the tubular member 20.

[0024] (B4) In the manufacturing method of the metal product of the first embodiment described above, the material of the plate-shaped member 10, the material of the tubular member 20, and the material of the additional member 30 are the same. In contrast, the material of one of the plate-shaped member 10, the tubular member 20, and the additional member 30 may be different from the material of the other two members. For example, the material of the plate-shaped member 10 and the material of the tubular member 20 may be the same, and the material of the additional member 30 may be different from the material of the plate-shaped member 10 and the material of the tubular member 20. In this case, for example, the material of the additional member 30 may be free-cutting steel to make it easier to remove the additional member 30 in the removal step, and the material of the additional member 30 may be a material with a higher thermal conductivity than the material of the tubular member 20 to make it easier to disperse the heat of the tubular member 20 to the additional member 30 in the welding step. In addition, the material of the plate-shaped member 10, the material of the tubular member 20, and the material of the additional member 30 may be different from each other.

[0025] (B5) In the manufacturing method of a metal product of the first embodiment described above, after the welding step of step S20, at least a part of the additional member 30 is removed in the removal step of step S30. In contrast, if it is acceptable for the additional member 30 to remain on the metal product, the manufacturing method of a metal product does not have to include the removal step of step S30.

[0026] The present disclosure is not limited to the above-mentioned embodiment, and can be realized in various configurations without departing from the spirit of the present disclosure. For example, the technical features in the embodiments corresponding to the technical features in each aspect described in the Summary of the Invention column can be appropriately replaced or combined to solve some or all of the above-mentioned problems or to achieve some or all of the above-mentioned effects. Furthermore, if the technical feature is not described as essential in this specification, it can be appropriately deleted. [Explanation of symbols]

[0027] 10...plate-like member, 15...through hole, 20...tubular member, 30...additional member, 40...weld portion, 50...assembly, 100...flanged piping-like member, 110...flange portion, 120...tube portion, 200...heat exchanger, 210...flange portion, 220...tube portion, 230...shell portion, PL2...overlap portion, PL3...overlap portion, RL...overlap region, TL...cutting tool, WT...welding torch

Claims

1. A method for manufacturing a metal product, comprising the steps of: a preparation step of preparing an assembly in which an end of a tubular member is inserted into a through hole of a plate-like member and an additional member is inserted into the end of the tubular member; a welding step of welding the tubular member and the plate-like member of the assembly; a removing step of removing at least a portion of the additional member from the assembly after the welding step; having The additional member is a columnar body, In the removing step, a through hole is formed in the additional member.

2. A method for manufacturing a metal product, comprising the steps of: a preparation step of preparing an assembly in which an end of a tubular member is inserted into a through hole of a plate-like member and an additional member is inserted into the end of the tubular member; a welding step of welding the tubular member and the plate-like member of the assembly; a removing step of removing at least a portion of the additional member from the assembly after the welding step; having The additional member is a cylindrical body, In the removing step, an inner diameter of the additional member is enlarged.

3. A method for producing a metal product according to claim 1 or 2, A method for manufacturing a metal product, wherein a volume of an overlap of the additional member with the tubular member in the assembly is greater than a volume of an overlap of the tubular member with the additional member in the assembly.

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