Method for manufacturing structure, and structure

Abstract

The invention provides a method for manufacturing a structure and a structure. The present invention addresses the problem of suppressing the formation of pores that cause large dimples during overlap welding. As a solution, provided is a method for manufacturing a structure (1) in which a metal member (11) and a metal member (12), which overlap each other, are bonded by irradiation of a laser beam (20), the method including a first step in which the laser beam (20) is irradiated with the metal member (11) and the metal member (12), and a second step in which the laser beam (20) is irradiated with the metal member (11) and the metal member (12). In the first step, welding is performed in a predetermined direction while the laser light (20) is irradiated, and in the second step, welding is performed in the predetermined direction while the laser light (20) is irradiated to a position that is offset in a direction intersecting the predetermined direction with respect to the irradiation position of the laser light (20) in the first step, and in the second step, welding is performed in the predetermined direction while the laser light (20) is irradiated to a position that is offset in the direction intersecting the predetermined direction with respect to the irradiation position of the laser light (20) in the first step. And a position where a new molten pool (112) is formed so as to overlap the molten pool (111) formed in the first step.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a structure and the structure. Background Art

[0002] In so-called lap welding (lap welding) in which two overlapping metal members are joined by irradiating laser, one weld bead is formed by irradiating laser once or multiple times (for example, Patent Documents 1 and 2). In addition, it is known that a technique is used to suppress the formation of pores during remelting by melting a metal member to release the gas inside (for example, Patent Document 3).

[0003] Prior Art Literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2021-20230

[0006] Patent Document 2: Japanese Patent Application Laid-Open No. 11-138282

[0007] Patent Document 3: Japanese Patent Application Laid-Open No. 08-206838 Summary of the invention

[0008] Die-casting materials formed by pouring molten nonferrous metals into a mold are suitable for products with high dimensional accuracy and complex shapes, and can suppress manufacturing costs. However, die-casting materials are considered to be difficult to weld materials with difficulty in welding. When laser welding thin die-casting materials is performed, they are sometimes thermally deformed by high-output lasers. In addition, when welding is completed by a single laser irradiation and when welding is completed by multiple laser irradiations of the same part, the molten pool becomes larger and deeper, so it becomes easy to produce large pits, i.e., hole defects, caused by pores formed inside. As a result, the appearance and / or interior of the welded part may be defective, i.e., poor welding, reduced strength of the welded part, reduced airtightness of the welded part, etc.

[0009] An object of the present invention is to suppress the formation of pores which may cause large pits during lap welding.

[0010] The present invention completed with such an object in mind is a method for manufacturing a structure, the method comprising: irradiating two overlapping members with a laser to join the two members; the method comprising a first step and a second step.

[0011] In the first step, welding is performed in a predetermined direction while irradiating the laser beam.

[0012] In the second process, welding is performed in the specified direction while irradiating the laser to the following position, which is a position that is offset in a direction intersecting the specified direction relative to the irradiation position of the laser in the first process and is a position where a new molten pool is formed in a manner that overlaps with the molten pool formed in the first process.

[0013] Here, at least one of the two members may be a die-cast material.

[0014] In addition, one of the two members may be an easily weldable material.

[0015] In the second step, welding may be performed while shifting the welding position so that the distance between the weld bead formed in the first step and the weld bead formed in the second step becomes equal to or less than half of the final joint width.

[0016] Furthermore, in the second step, the laser beam may be irradiated so as to fill the pores formed in the molten pool in the first step.

[0017] In addition, the welding speed may be 100 mm / s or more.

[0018] In addition, a third step may be further included, in which welding is performed in the prescribed direction while irradiating the laser to the following position, wherein the position is shifted in a direction intersecting the prescribed direction relative to the irradiation position of the laser in the second step, and is a position where a molten pool is formed again in a manner that overlaps with the molten pools formed respectively in the first step and the second step.

[0019] In addition, the present invention completed with such a purpose is a structure formed by joining two overlapping components by irradiating the two components with a laser, wherein a plurality of weld beads extending in a predetermined direction are arranged in a direction intersecting the predetermined direction, and adjacent molten pools overlap.

[0020] According to the present invention, when performing lap welding, the formation of pores which may cause large pits can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a cross-sectional view showing an example of a structure according to an embodiment of the present invention.

[0022] Figure 2 This is a cross-sectional view showing an example of a structure manufactured by conventional lap welding.

[0023] Figure 3(A) is a diagram showing a specific example of a weld bead formed by applying the lap welding of the present embodiment, (B) is a cross-sectional view obtained by cutting the molten pool formed by applying the lap welding of the present embodiment in the welding direction after solidification, and (C) is a diagram showing four modes of combination of two metal components constituting a structure.

[0024] Figure 4 (A) to (C) are diagrams showing specific examples of a welding method when a large pit is formed in a molten pool by lap welding to which the present embodiment is applied.

[0025] Description of Reference Numerals

[0026] 1…structure; 11, 12…metal component; 111, 112, 113, 211, 212, 213…molten pool; 20…laser; 121, 122, 123…weld bead. DETAILED DESCRIPTION

[0027] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0028] (Configuration of this embodiment)

[0029] Figure 1 1 is a cross-sectional view showing an example of a structure 1 according to an embodiment of the present invention. Figure 1 The cross-sectional view shown is a view obtained by cutting the structure 1 in a direction intersecting the welding direction of the irradiation laser 20. That is, Figure 1 The molten pool shown in FIG. 1 is formed by the laser 20 moving from the back side to the front side of the drawing or from the front side to the back side of the drawing.

[0030] like Figure 1 As shown in FIG. 1 , the structure 1 is a structure manufactured by overlapping and joining a metal member 11 disposed on the upper side and a metal member 12 disposed on the lower side. Specifically, the structure 1 is obtained by lap welding the two overlapping metal members 11 and 12 by irradiating a laser 20 in a direction from the upper side to the lower side. Since the manufacturing process includes a step of lap welding the metal members 11 and the metal members 12, the shape and size of the structure 1 are not particularly limited.

[0031] In the lap welding to which this embodiment is applied, the irradiation positions are staggered and the laser is irradiated multiple times in the same direction. Figure 1, an example of irradiating the laser 20 three times in the same direction with the irradiation positions staggered is shown. Specifically, an example is shown in which a molten pool 111 is formed by the first irradiation of the laser 20, a molten pool 112 is formed by the second irradiation of the laser 20, and a molten pool 113 is formed by the third irradiation of the laser 20.

[0032] In the lap welding to which this embodiment is applied, the irradiation positions are staggered and the laser is irradiated multiple times so that adjacent molten pools partially overlap. Figure 1 In the example, the metal member 11 and the metal member 12 are welded in such a manner that adjacent molten pools partially overlap. Specifically, the metal member 11 and the metal member 12 are welded in such a manner that a portion of the molten pool 111 overlaps a portion of the molten pool 112, and the metal member 11 and the metal member 12 are welded in such a manner that a portion of the molten pool 112 overlaps a portion of the molten pool 113.

[0033] Furthermore, there is no particular limitation on the degree to which the irradiation positions are offset. Since adjacent molten pools only need to partially overlap, for example, the irradiation positions may be offset so that the interval between adjacent weld beads formed by welding becomes less than half of the final joint width. In addition, the welding speed is also not particularly limited. Since adjacent molten pools only need to partially overlap, for example, the welding conditions may be set so that the welding speed becomes 100 mm / s or more.

[0034] According to the lap welding using this embodiment, even if pores are generated inside the molten pool formed by laser irradiation, the pores can be blocked by the next laser irradiation at a different irradiation position. In addition, even if an explosion occurs in the molten pool formed by laser irradiation and a large pit is formed on the surface of the molten pool, molten metal flows from the molten pool formed by the next laser irradiation at a different irradiation position toward the large pit, thereby eliminating or reducing the large pit.

[0035] Specifically, for example, in Figure 1 In the example of , even if pores are generated inside the molten pool 111 formed by the first irradiation of the laser 20, the pores are blocked by the second irradiation of the laser 20. That is, when the molten pool 112 is formed by the second irradiation of the laser 20, the laser 20 is irradiated in a manner such that the molten pool 112 and the molten pool 111 partially overlap, and therefore, the molten pool 111 solidified after the first irradiation of the laser 20 is remelted to block the pores. Similarly, even if pores are generated inside the molten pool 112 formed by the second irradiation of the laser 20, the pores are blocked by the third irradiation of the laser 20.

[0036] In addition, for example, even if an explosion occurs in the molten pool 111 formed by the first irradiation of the laser 20, thereby generating a large pit on the surface of the molten pool 111, molten metal will flow from the molten pool 112 formed by the second irradiation of the laser 20 toward the molten pool 111 to eliminate or reduce the large pit. Similarly, even if an explosion occurs in the molten pool 112 formed by the second irradiation of the laser 20, molten metal will flow from the molten pool 113 formed by the third irradiation of the laser 20 toward the molten pool 112 to eliminate or reduce the large pit. Furthermore, a specific example of a welding method in which an explosion occurs in the molten pool, thereby generating a large pit on the surface of the molten pool, will be described later. Figure 4 To narrate.

[0037] Figure 2 1 is a cross-sectional view showing an example of a structure manufactured by conventional lap welding. Figure 2 The cross-sectional view shown is similar to the above Figure 1 The cross-sectional view shown is also a cross-sectional view obtained by cutting the structure in a direction intersecting the direction of welding by irradiating the laser. Figure 2 The molten pool shown in FIG. 1 is formed by using a laser that moves from the back side to the front side of the drawing or from the front side to the back side of the drawing.

[0038] In the case of conventional lap welding, the welding is completed by irradiating the laser once with high output power or irradiating the laser to the same part multiple times. Therefore, the depth of the molten pool formed during welding is deeper than that of the lap welding to which this embodiment is applied. If the molten pool is deep, the airtightness after welding is improved, but the risk of gas generation and intrusion during melting becomes higher, so the risk of forming pores becomes higher.

[0039] In contrast, the molten pool formed by applying the lap welding of this embodiment is as described above. Figure 1 shown, than Figure 2 The molten pool formed by the conventional lap welding is shallow, so the risk of forming pores during welding is reduced. In addition, since the molten pool formed by the lap welding according to the present embodiment is shallower than the molten pool formed by the conventional lap welding and the weld width is narrower, it is inferior to the conventional lap welding in that airtightness can be ensured by welding once, but since the weld width can be expanded by welding multiple times, airtightness can be ensured in the end.

[0040] Figure 3 (A) is a diagram showing a specific example of a weld bead formed by applying lap welding according to the present embodiment. Figure 3 (B) is a cross-sectional view obtained by cutting the molten pool formed by lap welding according to the present embodiment in the welding direction after solidification.

[0041] If the above Figure 1 When the molten pools 111 to 113 shown in FIG. solidify, three weld beads are formed on the surface of the metal component 11 of the structure 1. Specifically, Figure 3 As shown in (A), three weld beads 121 to 123 are formed.

[0042] The weld bead 121 is a molten pool 111 (see Figure 1 ) is solidified. The weld bead 122 is a molten pool 112 formed by the second irradiation of the laser 20 (see Figure 1 ) is solidified. The weld bead 123 is a molten pool 113 formed by the irradiation of the third laser 20 (see Figure 1 ) obtained by solidification.

[0043] like Figure 3 As shown in (A), no large pit is formed in any of the three welds 121 to 123. Figure 3 (B) As shown in the above Figure 1 Pores are not formed in any of the welded portions 131 to 133 obtained by solidifying the molten pools 111 to 113 .

[0044] Figure 3 (C) is a diagram showing four modes of combination of two metal members constituting the structure 1 .

[0045] The two metal members constituting the structure 1 according to the present embodiment are not particularly limited. For example, they may be relatively easy-to-weld materials such as stainless steel, carbon steel, cast iron, and high-alloy steel, or difficult-to-weld materials such as die-cast materials (aluminum alloys, magnesium alloys, etc.), nickel-based alloys, and high-strength steel. In addition, a combination of these is also possible.

[0046] For example, Figure 3 As shown in (C), as the first combination mode, the easy-to-weld material can be arranged on the upper side and the difficult-to-weld material can be arranged on the lower side. In addition, as the second combination mode, the difficult-to-weld material can be arranged on the upper side and the easy-to-weld material can be arranged on the lower side. In addition, as the third combination mode, the easy-to-weld material can be arranged on the upper side and the easy-to-weld material can also be arranged on the lower side. In addition, as the fourth combination mode, the difficult-to-weld material can be arranged on the upper side and the difficult-to-weld material can also be arranged on the lower side.

[0047] exist Figure 3In the four patterns of the combination shown in (C), in the case of the pattern of the combination of the easy-to-weld material and the difficult-to-weld material, that is, in the pattern of arranging the easy-to-weld material on the upper side and the difficult-to-weld material on the lower side, or in the pattern of arranging the difficult-to-weld material on the upper side and the easy-to-weld material on the lower side, a part of the easy-to-weld material and a part of the difficult-to-weld material are mixed in the molten pool during welding. Therefore, even if the difficult-to-weld material is a metal material with a large amount of gas compressed inside during casting, such as a die-cast material, the size of the explosion can be reduced by controlling the welding conditions in a manner that suppresses the proportion of the difficult-to-weld material in the molten pool.

[0048] For example, in the case of a mode in which an easy-to-weld material is arranged on the upper side and a difficult-to-weld material is arranged on the lower side, the proportion of the difficult-to-weld material in the molten pool can be suppressed by performing welding in a manner that makes the welding range as wide as possible and the molten pool as shallow as possible. In addition, for example, in the case of a mode in which a difficult-to-weld material is arranged on the upper side and an easy-to-weld material is arranged on the lower side, the proportion of the difficult-to-weld material in the molten pool can be suppressed by performing welding in a manner that makes the welding range as narrow as possible and the molten pool as deep as possible.

[0049] Figure 4 (A) to (C) are diagrams showing specific examples of a welding method when a large pit is formed in the molten pool by lap welding to which the present embodiment is applied.

[0050] exist Figure 4 (A) to (C) show cross-sectional views of the structure 1 cut in a direction intersecting the direction in which the laser head irradiating the laser 20 moves. The structure 1 is a structure manufactured by overlapping and joining a metal member 11 disposed on the upper side and a metal member 12 disposed on the lower side. That is, Figure 4 The molten pools shown in (A) to (C) are formed by irradiating the laser light 20 from the laser head moving from the back side to the front side of the drawing or from the front side to the back side of the drawing.

[0051] exist Figure 4 (A) shows an example in which the irradiation positions are staggered and the laser 20 is irradiated four times in the same direction. Specifically, the example in which the molten pool 211 is formed by the first irradiation of the laser 20, the molten pool 212 is formed by the second irradiation of the laser 20, the molten pool 213 is formed by the third irradiation of the laser 20, and the molten pool 214 is formed by the fourth irradiation of the laser 20 is shown.

[0052] As described above, according to the lap welding using the present embodiment, even if pores are generated inside the molten pool formed by laser irradiation, the pores are blocked by the next laser irradiation at a different irradiation position. In addition, even if an explosion occurs in the molten pool formed by laser irradiation and a large pit is formed on the surface of the molten pool, molten metal flows from the molten pool formed by the next laser irradiation at a different irradiation position toward the large pit portion, thereby eliminating or reducing the large pit.

[0053] However, when the number of weld beads formed by the lap welding according to the present embodiment is set as n (n is an integer greater than or equal to 2) as a welding condition, pores and / or large pits caused by explosions may occur in the molten pool formed by the nth irradiation. In such a case, the laser is irradiated again toward the n-1th irradiation position. In other words, the n+1th irradiation is performed toward the n-1th irradiation position. Then, the portion melted and solidified by the n-1th irradiation is re-melted by re-irradiation (i.e., the n+1th irradiation). Moreover, a part of the portion melted and solidified by the nth irradiation is re-melted. As a result, the pores generated by the nth irradiation are blocked.

[0054] In addition, when an explosion occurs in the molten pool formed by the nth irradiation and a large pit is formed on the surface of the molten pool, the laser is re-irradiated toward the n-1th irradiation position. Then, the portion melted and solidified by the n-1th irradiation is re-melted by re-irradiation (i.e., n+1th irradiation). Moreover, part of the portion melted and solidified by the nth irradiation is re-melted. As a result, the re-melted metal flows into the large pit, and the large pit is eliminated or reduced.

[0055] Specifically, for example, Figure 4 As shown in (A), it is assumed that an explosion occurs in the molten pool 214 formed by the irradiation of the laser 20 for the fourth time, and a concave portion 300 is formed on the surface of the molten pool 214. In this case, Figure 4 As shown in (B), the laser beam 20 is irradiated again toward the third irradiation position. Then, a part of the portion (region 215) melted and solidified by the third and fourth irradiations is re-melted by the re-irradiation (i.e., the fifth irradiation). As a result, the re-melted metal flows into the concave portion 300, as shown in FIG. Figure 4 (C) shows a molten pool 216. As a result, Figure 4 (B) The recessed portion 300 is eliminated or reduced. Whether the recessed portion 300 is formed can be detected, for example, by visual inspection of an operator or by various sensors (for example, a camera that captures images of welded portions) not shown.

[0056] In summary, the method for manufacturing the structure 1 and the structure 1 to which the present invention is applied are sufficient to adopt the following configurations, and various embodiments can be adopted.

[0057] That is, the manufacturing method of the structure 1 to which the present invention is applied is a manufacturing method of the structure 1 formed by joining two overlapping components (metal components 11 and 12) by irradiating the two overlapping components with a laser 20, and includes a first step and a second step, in which the laser head is moved in a predetermined direction (a direction along a position predetermined as the irradiation position of the laser 20) while irradiating the laser 20, and in the second step, the laser head is moved in a predetermined direction while irradiating the laser 20 to the following position, which is a position that is offset from the irradiation position of the laser 20 in the first step in a direction intersecting with the predetermined direction (the direction in which the laser head that irradiates the laser 20 moves), and is a position at which a new molten pool (for example, molten pool 112) is formed in a manner that overlaps with the molten pool (for example, molten pool 111) formed in the first step.

[0058] Thus, the laser head is moved in a predetermined direction while irradiating the laser 20 to the following position, which is a position that is offset in a direction intersecting the predetermined direction relative to the irradiation position of the laser 20 in the first process and is a position where a new molten pool is formed in a manner overlapping the molten pool formed in the first process, so that a plurality of weld beads are formed in a manner that adjacent molten pools overlap. As a result, compared with the case where welding is completed by only one irradiation of the laser 20, the molten pool formed by each irradiation of the laser 20 becomes smaller and shallower, so fewer pores are formed inside the component. In addition, even if the upper component is a thin and difficult-to-weld material, it becomes difficult to thermally deform. In addition, by increasing the number of weld beads, airtightness can be ensured without deepening the molten pool.

[0059] Here, at least one of the two overlapping members may be a die-cast material.

[0060] Thus, even when welding a material such as a die-cast material in which pores are easily formed, large pits are reduced and thermal deformation becomes difficult.

[0061] In addition, one of the two overlapping members may be made of an easily weldable material.

[0062] Thus, even when welding a difficult-to-weld material such as a die-cast material in which pores are easily formed during welding and an easy-to-weld material that is easy to weld, large craters are reduced and thermal deformation is less likely to occur.

[0063] In addition, in the second step, the welding positions may be shifted so that the interval between the weld bead formed in the first step (for example, weld bead 121) and the weld bead formed in the second step (for example, weld bead 122) becomes less than half of the final joint width.

[0064] Thus, by approaching so that the interval between the weld beads becomes less than half of the final joining width, the pores formed in the first step can be filled by the irradiation of the laser beam in the second step.

[0065] In the second step, the laser beam 20 may be irradiated so as to fill the pores formed in the molten pool in the first step.

[0066] Thereby, the pores formed in the first step can be filled by irradiation with laser light in the second step.

[0067] In addition, the welding speed may be 100 mm / s or more.

[0068] Thus, since the laser beam is irradiated at a speed of 100 mm / s or more, the time cost that would be incurred by performing the laser beam irradiation a plurality of times can be reduced.

[0069] In addition, a third step may be further included, in which the following position (for example, Figure 4 (A) irradiates the laser beam 20 (for example, Figure 4 The fifth irradiation shown in (B) is performed while welding in a specified direction, and the position is a position that is offset from the irradiation position of the laser 20 in the second process in a direction intersecting the specified direction, and is a position where a molten pool (for example, molten pool 216) is formed again in a manner overlapping with the molten pools (for example, molten pools 213 and 214) formed in the first process and the second process, respectively.

[0070] Thus, the laser is irradiated to the following position, which is a position that is offset from the irradiation position of the laser in the second process in a direction intersecting the prescribed direction and is a position where a molten pool is formed again in a manner overlapping with the molten pools formed in the first process and the second process, respectively. Therefore, it is possible to repair the pores and / or explosions generated in the second process.

[0071] In addition, the structure 1 completed for the aforementioned purpose is a structure formed by joining two overlapping components (metal components 11 and 12) by irradiating the two components with a laser 20, and a plurality of weld beads 121 to 123 extending in a predetermined direction are arranged in a direction intersecting the predetermined direction, and adjacent molten pools (for example, molten pool 112 and adjacent molten pools 111 and 113) overlap.

[0072] Thus, welding is performed in a predetermined direction while irradiating the laser to the following position, which is a position shifted in a direction intersecting the predetermined direction relative to the irradiation position of the laser in the first process and a position where a new molten pool is formed in a manner overlapping the molten pool formed in the first process, so that a plurality of weld beads are formed in a manner that adjacent molten pools overlap. As a result, compared with the case where welding is completed by only one laser irradiation, the molten pool formed by each laser irradiation becomes smaller and shallower, so the number of pits caused by pores formed inside the component decreases. In addition, even if the upper component is a thin and difficult-to-weld material, it becomes difficult to be thermally deformed. In addition, by increasing the number of weld beads, airtightness can be ensured without deepening the molten pool.

[0073] (Other embodiments)

[0074] The embodiments of the present invention have been described above, but the present invention is not limited to the above-mentioned embodiments. Figure 1 The structure 1 and the welding method shown are merely examples for achieving the purpose of the present invention and are not particularly limited. In addition, the effects achieved by the present invention are not limited to those described in the above-mentioned embodiment.

[0075] For example, in Figure 1 In the example, the number of times of welding while irradiating the laser 20 is 3 times, but it is not limited to this. Since the number of times of welding while irradiating the laser 20 only needs to be two or more times, it can be as follows Figure 4 As in the example of , it may be 5 times, or it may be more times.

[0076] In addition, for example, Figure 4 In the examples shown in (A) and (B), after the fourth irradiation, re-irradiation is performed to the irradiation position of the third time (i.e., the fifth irradiation), but the number of re-irradiation is not limited to 1. For example, after re-irradiation to the irradiation position of the third time (i.e., the fifth irradiation), re-irradiation to the irradiation position of the second time (i.e., the sixth irradiation) may be performed, and further re-irradiation to the irradiation position of the first time (i.e., the seventh irradiation) may be performed thereafter.

Claims

1. A method for manufacturing a structure, wherein the method comprises joining two overlapping members by irradiating the two members with a laser, the method comprising a first step and a second step, In the first step, welding is performed in a predetermined direction while irradiating the laser beam. In the second process, welding is performed in the specified direction while irradiating the laser to the following position, which is a position that is offset in a direction intersecting the specified direction relative to the irradiation position of the laser in the first process and is a position where a new molten pool is formed in a manner that overlaps with the molten pool formed in the first process.

2. The method for manufacturing a structure according to claim 1, At least one of the two members is a die-cast material.

3. The method for manufacturing a structure according to claim 2, One of the two members is an easily weldable material.

4. The method for manufacturing a structure according to claim 1, In the second step, welding is performed while shifting the welding positions so that the interval between the weld bead formed in the first step and the weld bead formed in the second step becomes equal to or less than half of the final joint width.

5. The method for manufacturing a structure according to claim 4, In the second step, the laser beam is irradiated so as to fill the pores formed in the molten pool in the first step.

6. The method for manufacturing a structure according to claim 1, The welding speed is above 100 mm / s.

7. The method for manufacturing a structure according to claim 1, The invention also includes a third step, in which welding is performed in the prescribed direction while irradiating the laser to the following position, wherein the position is shifted in a direction intersecting the prescribed direction relative to the irradiation position of the laser in the second step, and the position is formed again in a manner that overlaps with the molten pools respectively formed in the first step and the second step.

8. A structure formed by joining two overlapping members by irradiating the two members with a laser, A plurality of weld beads extending in a predetermined direction are arranged in a direction intersecting the predetermined direction, and adjacent molten pools overlap.

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