Method for producing welded member

Abstract

To provide a technique for easily forming a welded member without a hole caused by a gap even when the gap is formed between butted end faces of two metal plates.SOLUTION: In the method for manufacturing a welded member, an irradiation region that is a region irradiated with the laser beam is relatively moved along the end surface. The irradiation region includes a first region, a second region, and a third region. The second region is a region surrounding an outer periphery of the first region. The third area is an area located outside the second area and at least in front of the second area in the moving direction. The movement direction is a direction in which the irradiation region relatively moves. In the moving direction, a rear end of the third region is located on the front side of a rear end of the second region. The power densities q1 of the laser beams with which the first region is irradiated, the power densities q2 of the laser beams with which the second region is irradiated, and the power densities q3 of the laser beams with which the third region is irradiated satisfy a relationship of q1> q2, q3.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing a welded component. [Background technology]

[0002] For example, Patent Document 1 describes a method of welding two metal plates to form a welded member by butting the end faces of the two metal plates together and irradiating a laser beam along the end faces. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-7119 Summary of the Invention [Problem to be solved by the invention]

[0004] In this type of manufacturing method for welded parts, when the end faces of two metal plates are butted together, a gap may form between the end faces. In this case, even if the laser beam is irradiated, the gap between the end faces may not be sufficiently closed, and a hole caused by the gap may remain in the finished welded part.

[0005] One aspect of the present disclosure provides a technology that makes it easier to form a welded member that is free of holes caused by a gap, even when a gap is formed between the butted end faces of two metal plates. [Means for solving the problem]

[0006] One aspect of the present disclosure is a method for manufacturing a welded member, comprising: abutting end faces of a first metal plate and a second metal plate and irradiating a laser beam along the end faces to weld the first metal plate and the second metal plate to form a welded member. The irradiation region, which is the region irradiated with the laser beam, moves relatively along the end faces. The irradiation region has a first region, a second region, and a third region. The second region is a region surrounding the outer periphery of the first region. The third region is a region located outside the second region and at least forward of the second region in the movement direction. The movement direction is the direction in which the irradiation region moves relatively. In the movement direction, the rear end of the third region is located forward of the rear end of the second region. The power density q1 of the laser beam irradiated to the first region, the power density q2 of the laser beam irradiated to the second region, and the power density q3 of the laser beam irradiated to the third region satisfy the relationship q1>q2,q3.

[0007] With this configuration, even if a gap is formed between the butted end faces of the first metal plate and the second metal plate, it is possible to easily form a welded member that does not have holes caused by the gap.

[0008] In one aspect of the present disclosure, the power density q1 of the laser beam irradiated to the first region, the power density q2 of the laser beam irradiated to the second region, and the power density q3 of the laser beam irradiated to the third region may satisfy the relationship q1>q3>q2. With this configuration, even if a gap is formed between the butted end faces of the first metal plate and the second metal plate, it is possible to more easily form a welded member that is free of holes resulting from the gap.

[0009] In one aspect of the present disclosure, the second region may be in contact with the first region. This configuration can further suppress the occurrence of sputtering when irradiated with a laser beam.

[0010] In one aspect of the present disclosure, the dimension of the irradiation area in the movement direction may be smaller than the dimension in the direction perpendicular to the movement direction. With this configuration, even if a gap is formed between the butted end faces of the first metal plate and the second metal plate, it is possible to more easily form a welded member that is free of holes due to the gap.

[0011] In one embodiment of the present disclosure, the thickness of the first metal plate may be greater than the thickness of the second metal plate. [Brief explanation of the drawings]

[0012] [Figure 1] 5A to 5C are schematic diagrams illustrating a method for manufacturing a welded member. [Figure 2] FIG. 1 is a schematic diagram of a welding device. [Figure 3] FIG. 2 is a schematic enlarged partial view of the welding device. [Figure 4] FIG. 2 is a schematic diagram showing an irradiation area. [Figure 5] Fig. 5A is a schematic diagram illustrating a butting step, Fig. 5B is a schematic diagram illustrating a welding step, Fig. 5C is a schematic diagram illustrating a state after Fig. 5B in the welding step, and Fig. 5D is a schematic diagram illustrating a state after Fig. 5C in the welding step. [Figure 6] FIG. 1 is a schematic diagram showing the direction in which molten metal is attracted. [Figure 7] 7A to 7H are schematic diagrams showing modified examples of the irradiation region. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the drawings.

[0014] [1. Overview] As shown in Fig. 1, a first metal plate 10 and a second metal plate 20 are welded together to form a welded member 30. The first metal plate 10 and the second metal plate 20 are plate-shaped members made of metal. The first metal plate 10 and the second metal plate 20 are, for example, steel plates. A specific example of the steel plate is a galvanized steel plate.

[0015] The first metal plate 10 and the second metal plate 20 are, for example, flat. The first metal plate 10 and the second metal plate 20 are, for example, rectangular when viewed from the front. A front view of a plate-shaped member means that the plate-shaped member is viewed from an out-of-plane direction.

[0016] The thickness t1 of the first metal plate 10 is, for example, larger than the thickness t2 of the second metal plate 20. The thickness t1 of the first metal plate 10 means the dimension in the out-of-plane direction of the first metal plate 10 (i.e., the dimension from the front surface 11 to the back surface 12 of the first metal plate 10). The thickness t2 of the second metal plate 20 means the dimension in the out-of-plane direction of the second metal plate 20 (i.e., the dimension from the front surface 21 to the back surface 22 of the second metal plate 20).

[0017] 2 and 3, a welding apparatus 100 used to weld a first metal plate 10 and a second metal plate 20 together, and a method for manufacturing a welded component 30 using the welding apparatus 100 as shown in FIG. 1 will be described in detail below. When the welded component 30 is further subjected to other processing such as press forming, the welded component 30 is also referred to as a tailored blank. Note that when the welded component 30 is further subjected to other processing, for example, the first metal plate 10 and the second metal plate 20 constituting the welded component 30 may have shapes corresponding to the shape of the finished product after the other processing.

[0018] [2. Welding equipment] As shown in FIG. 2, the welding apparatus 100 includes a laser oscillator 110, an optical fiber 120, an optical head 130, a robot arm 140, and a gas nozzle 150.

[0019] The laser oscillator 110 is configured to generate a laser beam L. The laser oscillator 110 has a laser medium, an excitation source, and an optical resonator, none of which are shown. In the laser oscillator 110, the laser medium is excited by the excitation source. Then, the light emitted from the excited laser medium is amplified by the optical resonator, thereby generating a laser beam L with a coherent phase.

[0020] The optical fiber 120 forms an optical path for the laser beam L from the laser oscillator 110 to the optical head 130. The laser beam L generated by the laser oscillator 110 passes through the optical fiber 120 and is guided to the optical head 130.

[0021] The optical head 130 is configured to irradiate the first metal plate 10 and the second metal plate 20 with a laser beam L. The optical head 130 has a collimating lens 131, a diffractive optical element 132, and a focusing lens 133. The collimating lens 131, the diffractive optical element 132, and the focusing lens 133 are arranged in this order on the optical path of the laser beam L within the optical head 130. In other words, the laser beam L guided by the optical fiber 120 passes through the collimating lens 131, the diffractive optical element 132, and the focusing lens 133 in this order. The collimating lens 131 is configured to collimate the laser beam L. The diffractive optical element 132 is configured to branch the collimated laser beam L. The focusing lens 133 is configured to adjust the aperture of the branched laser beam L. For example, the focus lens 133 is configured to adjust the aperture of the laser beam L so that the laser beam L converges in front of the first metal plate 10 and the second metal plate 20.

[0022] The robot arm 140 has a plurality of links connected by a plurality of joints. The optical head 130 is attached to the tip of the robot arm 140. The robot arm 140 is configured to be able to move the optical head 130 with six degrees of freedom.

[0023] When the optical head 130 is irradiating the laser beam L, the robot arm 140 moves the optical head 130, thereby relatively moving the irradiation area 40 shown in FIG. 4 . The irradiation area 40 is the area irradiated with the laser beam L. The length M1 of the irradiation area 40 is smaller than the width M2 of the irradiation area 40. The length M1 of the irradiation area 40 is the dimension of the irradiation area 40 in the movement direction D. The width M2 of the irradiation area 40 is the dimension of the irradiation area 40 in a direction perpendicular to the movement direction D. The movement direction D is the direction in which the irradiation area 40 moves relatively. When the laser beam L is irradiated onto the first metal plate 10 and the second metal plate 20, the movement direction D is the direction in which the irradiation area 40 moves relatively to the first metal plate 10 and the second metal plate 20. The irradiation area 40 has a first area 41, a second area 42, and a third area 43.

[0024] The first region 41 is a circular region. In this embodiment, the first region 41 is a perfect circle. As shown in FIG. 5B, the diameter of the first region 41 is larger than the size of the gap that may be formed between the end face 13 of the first metal plate 10 and the end face 23 of the second metal plate 20 (i.e., the distance between the end faces 13, 23). As shown in FIG. 1, the end face 13 of the first metal plate 10 is a surface that connects the front surface 11 and the back surface 12 of the first metal plate 10. The end face 23 of the second metal plate 20 is a surface that connects the front surface 21 and the back surface 22 of the second metal plate 20.

[0025] As shown in FIG. 4, the second region 42 is a region that surrounds the outer periphery of the first region 41. The second region 42 is annular. In this embodiment, the outer shape of the second region 42 is a perfect circle. The second region 42 is in contact with the first region 41. The fact that the first region 41 and the second region 42 are in contact with each other can also be rephrased as the first region 41 and the second region 42 being continuous with each other. Specifically, the second region 42 is in contact with the first region 41 over the entire circumference along the outer periphery of the first region 41.

[0026] The width of the second region 42 is, for example, equal to the diameter of the first region 41. In other words, the width of the second region 42 is the dimension in the radial direction of the second region 42. The radial direction here refers to the direction from the center C of the first region 41 toward the outside of the first region 41 (i.e., the second region 42 side). The same applies below. In other words, the width of the second region 42 is the difference between the outer diameter and the inner diameter of the second region 42.

[0027] The third region 43 is a region located outside the second region 42 and at least forward of the second region 42 in the movement direction D. The fact that the third region 43 is located at least forward of the second region 42 in the movement direction D can also be said to mean that at least a portion of the third region 43 is located forward of the second region 42 in the movement direction D. In the movement direction D, the front end 43x of the third region 43 is located forward of the front end 42x of the second region 42.

[0028] The third region 43 extends in an arc shape along the outer periphery of the second region 42. In this embodiment, since the outer shape of the second region 42 is a perfect circle, the third region 43 extends in an arc shape along the outer periphery of the perfect circle. In this embodiment, the central angle of an imaginary arc X that continues from one end of the third region 43 to the other end along the extension direction of the third region 43 is 180°. Both ends of the third region 43 in the extension direction are at the same position in the movement direction D. The both ends of the third region 43 in the extension direction correspond to rear ends 43y, 43z of the third region 43 in the movement direction D, respectively.

[0029] The width of the third region 43 is, for example, equal to the diameter of the first region 41. Furthermore, for example, the width of the third region 43 is equal to the width of the second region 42. In other words, the width of the third region 43 is the dimension of the third region 43 in the radial direction.

[0030] The third region 43 is positioned with a gap between it and the second region 42. That is, the third region 43 is not in contact with the second region 42. The gap between the second region 42 and the third region 43 is equal to the width of the second region 42, for example.

[0031] In FIG. 4 , the first virtual line Y1 and the second virtual line Y2 are each indicated by a two-dot chain line. The first virtual line Y1 is a virtual line perpendicular to the movement direction D and passes through the center C of the first region 41. The second virtual line Y2 is a virtual line perpendicular to the movement direction D and passes through the rear end 42y of the second region 42. In the movement direction D, the rear ends 43y and 43z of the third region 43 are located forward of the rear end 42y of the second region 42 (i.e., forward of the second virtual line Y2). For example, in the movement direction D, the rear ends 43y and 43z of the third region 43 may be located at the same position as the center C of the first region 41 (i.e., on the first virtual line Y1) or may be located forward of the center C of the first region 41 (i.e., forward of the first virtual line Y1). In this embodiment, in the movement direction D, the rear ends 43y, 43z of the third region 43 are located at the same position as the center C of the first region 41. That is, the first virtual line Y1 in this embodiment passes through the rear ends 43y, 43z of the third region 43.

[0032] The laser beam L is uniformly irradiated onto each of the first to third regions 41 to 43. The power density of the laser beam L irradiated onto each of the first to third regions 41 to 43 is constant throughout each region. The power density is the output of the laser beam L per unit area of ​​each region. The power density q1 of the laser beam L irradiated onto the first region 41, the power density q2 of the laser beam L irradiated onto the second region 42, and the power density q3 of the laser beam L irradiated onto the third region 43 satisfy the relationship q1>q2, q3. In this embodiment, these power densities q1 to q3 satisfy the relationship q1>q3>q2.

[0033] Returning to FIG. 2 , the gas nozzle 150 is configured to inject a gas G. Specific examples of the gas G include air, argon, and nitrogen. The gas nozzle 150 is configured to be movable together with the optical head 130. As an example, the gas nozzle 150 is attached to the optical head 130.

[0034] When the optical head 130 is moved, the gas nozzle 150 is disposed in front of the optical head 130 in the movement direction D. The gas nozzle 150 injects the gas G from the front side of the laser beam L in the movement direction D to the front of the irradiation region 40. This prevents the metal vapor generated by the irradiation of the first metal plate 10 and the second metal plate 20 with the laser beam L from remaining in the irradiation region 40.

[0035] [3. Manufacturing method for welded components] 1, the method for manufacturing the welded member 30 is a method for manufacturing the welded member 30 from a first metal plate 10 and a second metal plate 20. The method for manufacturing the welded member 30 includes a butting step and a welding step.

[0036] [3-1. Butting process] As shown in Fig. 5A, in the butting process, the end face 13 of the first metal plate 10 and the end face 23 of the second metal plate 20 are butted together. When the end face 13 of the first metal plate 10 and the end face 23 of the second metal plate 20 are butted together, for example, these end faces 13, 23 may be in contact with each other without any gap, or as shown in Fig. 5A, there may be at least a partial gap between these end faces 13, 23. The first metal plate 10 and the second metal plate 20 are placed on a work table (not shown), for example, with the end faces 13, 23 butted together.

[0037] The drawings show an example in which the end faces 13, 23 of the first metal plate 10 and the second metal plate 20 are butted against each other with their respective front faces 11, 21 facing upward. However, the orientation of the first metal plate 10 and the second metal plate 20 is not limited, and the end faces 13, 23 of the first metal plate 10 and the second metal plate 20 may be butted against each other with their respective back faces 12, 22 facing upward, for example.

[0038] [3-2. Welding process] The welding process is carried out following the butting process. In the welding process, as shown in Fig. 1, a laser beam L is irradiated onto the first metal plate 10 and the second metal plate 20, thereby welding the first metal plate 10 and the second metal plate 20 together to form a welded member 30. Specifically, the process is as follows.

[0039] As shown in FIG. 2 , with the end faces 13, 23 of the first metal plate 10 and the second metal plate 20 butted against each other, a laser beam L is irradiated from an optical head 130 of a welding device 100 onto the vicinity of these end faces 13, 23. Then, as a robot arm 140 moves the optical head 130, an irradiation area 40 moves relatively along the end faces 13, 23 of the first metal plate 10 and the second metal plate 20, as shown in FIGS. 5B and 5C . The position of the optical head 130 is adjusted so that a first area 41 overlaps at least one of the end face 13 of the first metal plate 10 and the end face 23 of the second metal plate 20. If a gap is formed between the end faces 13, 23 of the first metal plate 10 and the second metal plate 20, the aperture of the laser beam L is adjusted so that the diameter of the first area 41 is larger than the gap.

[0040] As shown in FIG. 5C , while the irradiation region 40 is moving relative to the first metal plate 10, the laser beam L irradiated to the third region 43 first melts the metal in a portion including at least the end surfaces 13 and 23 of the first metal plate 10 and the second metal plate 20. The laser beam L then irradiates the second region 42 and the third region 43, further melting the metal. The molten metal forms a molten pool 50 connecting the first metal plate 10 and the second metal plate 20. The laser beam L irradiated to the first region 41 ensures the depth of the molten pool 50. The depth of the molten pool 50 is the dimension of the molten pool 50 in the irradiation direction of the laser beam L. The laser beam L irradiated to the second region 42 assists in the melting of the metal by the laser beam L irradiated to the first region 41. The laser beam L irradiated to the third region 43 ensures the width M4 of the molten pool 50, as shown in FIG. 6 . The width M4 of the molten pool 50 is the dimension of the molten pool 50 in a direction perpendicular to the movement direction D. In the following, the dimension of the molten pool 50 in the movement direction D will be referred to as the length M3 of the molten pool 50.

[0041] When the irradiation region 40 moves relatively, the metal melts in the newly overlapping portion with the irradiation region 40 and forms part of the molten pool 50. On the other hand, in the portion that no longer overlaps with the irradiation region 40, the temperature gradually drops and the metal solidifies. That is, the molten pool 50 moves relatively together with the irradiation region 40 in the movement direction D. Behind the molten pool 50 in the movement direction D, a joint 60, which is a portion where the metal has solidified, is formed. The joint 60 connects the first metal sheet 10 and the second metal sheet 20. The length M3 of the molten pool 50 is equal to the dimension in the movement direction D from the front end 43x of the third region 43 to the joint 60.

[0042] The laser beam L is irradiated along the end faces 13, 23 of the first metal plate 10 and the second metal plate 20. The irradiation area 40 moves relatively along these end faces 13, 23 from one end to the other of these end faces 13, 23. As a result, the first metal plate 10 and the second metal plate 20 are joined by a joint 60, as shown in FIG. 5D. As a result, a welded member 30 is obtained, as shown in FIG. 1.

[0043] [4. Effects] (4a) A molten pool 50 is formed by irradiating the first metal sheet 10 and the second metal sheet 20 with a laser beam. In the molten pool 50, the metal solidifies from the rear side in the direction of movement D. Generally, the volume of metal decreases as it solidifies. For this reason, as shown in FIG. 6 , in the molten pool 50, the molten metal (so-called molten metal) tends to be attracted toward the solidifying portion. That is, the molten metal tends to be attracted toward the rear side in the direction of movement D. In addition, the molten metal tends to be attracted by surface tension at the interface with the first metal sheet 10 and the interface with the second metal sheet 20. That is, the molten metal tends to be attracted toward the first metal sheet 10 (i.e., toward the end face 13) and the second metal sheet 20 (i.e., toward the end face 23). Note that in FIG. 6 , for ease of understanding, examples of the direction in which the molten metal is attracted are indicated by thick arrows.

[0044] If the molten metal is drawn too far backward in the movement direction D, toward the first metal sheet 10, or toward the second metal sheet 20, there is a possibility that the amount of molten metal will be insufficient immediately behind the irradiation area 40 in the movement direction D. This may result in the molten pool 50 no longer maintaining the state in which the first metal sheet 10 and the second metal sheet 20 are connected. In this case, as the metal solidifies, holes will form in the finished welded member 30 due to gaps between the end faces 13, 23 of the first metal sheet 10 and the second metal sheet 20.

[0045] Therefore, in the manufacturing method of this embodiment, a laser beam L having an irradiation region 40 including first to third regions 41 to 43 is used in the welding step. With this configuration, it is possible to start cooling the molten metal earlier than when the laser beam of the comparative example is used. The laser beam of the comparative example is, for example, a laser beam having an irradiation region that is a region surrounding the outer periphery of the second region 42, and having a region where the laser beam is uniformly irradiated instead of the third region 43.

[0046] By accelerating the start of cooling of the molten metal, the molten metal can be solidified before it is drawn too far backward in the movement direction D, toward the first metal sheet 10, or toward the second metal sheet 20. In other words, the molten metal can be solidified while the molten pool 50 maintains the state in which the first metal sheet 10 and the second metal sheet 20 are connected. As a result, even if a gap is formed between the end faces 13, 23 of the first metal sheet 10 and the second metal sheet 20 during the butting process, it is possible to easily form a welded member 30 that does not have holes due to the gap.

[0047] (4b) Furthermore, in the welding process, a laser beam L having an irradiation region 40 including first to third regions 41 to 43 is used, thereby forming a more stable molten pool 50. According to the inventors, this is because the second region 42 is located on the outer periphery of the first region 41, which has the highest power density, resulting in a gentle change in power density in the radial direction. A gentle change in power density in the radial direction also results in a gentle change in the temperature of the molten metal in the radial direction. As a result, a more stable molten pool 50 can be formed. The more stable the molten pool 50, the more effectively spatter can be suppressed, and the more easily the amount of molten metal can be secured. Therefore, even if a gap is formed between the end faces 13, 23 of the first metal sheet 10 and the second metal sheet 20, the gap can be easily sealed.

[0048] (4c) In the present embodiment, the power densities q1 to q3 of the laser beam L irradiated onto the first to third regions 41 to 43, respectively, satisfy the relationship q1>q3>q2. With this configuration, a more stable molten pool 50 can be formed while reducing the total output of the laser beam L, compared to, for example, a configuration in which the power densities q1 to q3 satisfy the relationship q1>q2>q3. Reducing the total output of the laser beam L reduces the power consumption of the welding apparatus 100, which in turn contributes to reducing the manufacturing cost of the welded member 30.

[0049] (4d) If a gap is formed between the end faces 13, 23 of the first metal plate 10 and the second metal plate 20 during the butting process, when the laser beam L is irradiated during the subsequent welding process, the laser beam L may leak through the gap between the end faces 13, 23 of the first metal plate 10 and the second metal plate 20.

[0050] However, when the power densities q1 to q3 of the laser beam L irradiated to the first to third regions 41 to 43 satisfy the relationship q1>q3>q2, the total output of the laser beam L leaking through the gap between the end faces 13, 23 of the first metal plate 10 and the second metal plate 20 can be reduced compared to when the power densities q1 to q3 satisfy the relationship q1>q2>q3. In other words, the loss of the laser beam L through the gap can be reduced. Therefore, even when a gap is formed between the end faces 13, 23 of the first metal plate 10 and the second metal plate 20, the laser beam L can be irradiated to more easily melt the portions of the first metal plate 10 and the second metal plate 20 including the end faces 13, 23. This more easily maintains the state in which the molten pool 50 connects the first metal plate 10 and the second metal plate 20. As a result, it is easier to form a welded member 30 without holes due to the gap between the end faces 13, 23.

[0051] (4e) The second region 42 is in contact with the first region 41. With this configuration, the change in power density in the radial direction can be made more gradual. Therefore, the effect of (4b) above can be more easily obtained.

[0052] (4f) In the moving direction D, the rear ends 43y, 43z of the third region 43 are located at the same position as the center C of the first region 41 or forward of the center C of the first region 41. In other words, the third region 43 is located forward of the center C of the first region 41 in the moving direction D. With this configuration, the cooling of the molten metal can be started more quickly. Therefore, the effect of (4a) above can be more easily achieved.

[0053] (4g) The length M1 of the irradiation area 40 is smaller than the width M2 of the irradiation area 40. This configuration allows the molten metal to start cooling more quickly. Therefore, the effect of (4a) above can be more easily achieved.

[0054] [5. Verification] The inventors manufactured a welded member 30 from a first metal plate 10 and a second metal plate 20 using the above-described manufacturing method. Both the first metal plate 10 and the second metal plate 20 were galvanized steel plates. The thickness t1 of the first metal plate 10 was 1.6 mm. The thickness t2 of the second metal plate 20 was 1.4 mm. In the butting process, a gap was intentionally left between the end faces 13, 23 of the first metal plate 10 and the second metal plate 20, and these end faces 13, 23 were butted against each other. Then, in the welding process, the first metal plate 10 and the second metal plate 20 were welded using a welding device 100. The power densities q1 to q3 of the laser beam L irradiated onto the first to third regions 41 to 43, respectively, were set to satisfy the relationship q1>q3>q2.

[0055] As a result, in both cases where the gap between the end faces 13, 23 of the first metal plate 10 and the second metal plate 20 in the butting process was set to 0.1 mm and 0.2 mm, a welded component 30 was obtained that was free of holes caused by the gap. In the welding process, the ratio M3 / M4 of the length M3 of the molten pool 50 to the width M4 of the molten pool 50 was approximately 3.6. Furthermore, in the welding process, the generation of spatter during irradiation with the laser beam L was suppressed.

[0056] 6. Other Embodiments Although the embodiments of the present disclosure have been described above, it goes without saying that the present disclosure is not limited to the above-described embodiments and can take on various forms.

[0057] (6a) In the above embodiment, the central angle of the imaginary arc X that continues from one end of the third region 43 to the other end along the extension direction of the third region 43 is 180°. The first imaginary line Y1 passes through the rear ends 43y, 43z of the third region 43. That is, both ends of the third region 43 in the extension direction are tangent to the first imaginary line Y1.

[0058] However, the central angle of the virtual arc X is not particularly limited. For example, as in the irradiation area 40A shown in Fig. 7A and the irradiation area 40B shown in Fig. 7B, the central angle of the virtual arc X that continues from one end to the other end of the third areas 43A, 43B along the extension direction of the third areas 43A, 43B may be less than 180°. In this case, for example, neither end of the third areas 43A, 43B in the extension direction may be in contact with the first virtual line Y1, as shown in Fig. 7A, or one of the ends may be in contact with the first virtual line Y1, as shown in Fig. 7B.

[0059] (6b) In the above embodiment, the laser beam L is uniformly irradiated onto the second region 42. The power density of the laser beam L irradiated onto the second region 42 is constant throughout the entire region. However, the second region may have, for example, multiple regions to which the power density of the irradiated laser beam L differs.

[0060] 7C shows, as an example, an irradiation region 40C having a second region 42C instead of the second region 42 described above. The second region 42C has a front region 421 and a rear region 422. The front region 421, together with the rear region 422, surrounds the outer periphery of the first region 41. The front region 421 is located forward of the center C of the first region 41 in the movement direction D. The rear region 422 is located rearward of the center C of the first region 41 in the movement direction D. The power density q1 of the laser beam L irradiated to the first region 41, the power density q21 of the laser beam L irradiated to the front region 421, the power density q22 of the laser beam L irradiated to the rear region 422, and the power density q3 of the laser beam L irradiated to the third region 43 satisfy the relationships q1>q21, q22, q3, and q21>q22. For example, these power densities q1, q21, q22, and q3 may satisfy the relationship q1>q3>q21>q22.

[0061] (6c) In the above embodiment, the irradiation area 40 has only the first to third areas 41 to 43. However, the irradiation area may further have a fourth area.

[0062] 7D shows an illumination region 40D that includes a fourth region 44D in addition to the first to third regions 41 to 43. The fourth region 44D is a region that extends in an arc shape along the outer periphery of the second region 42. The fourth region 44D is located behind the center C of the first region 41 in the movement direction D. The fourth region 44D is located with a gap between it and the second region 42. The fourth region 44D, together with the third region 43, surrounds the outer periphery of the second region 42.

[0063] 7E shows an irradiation region 40E that includes a fourth region 44E in addition to the first to third regions 41 to 43. The fourth region 44E is a region that extends in an arc shape along the outer periphery of the second region 42. The fourth region 44E is located between the second region 42 and the third region 43. The fourth region 44E is in contact with both the second region 42 and the third region 43.

[0064] 7F shows an irradiation region 40F that includes a fourth region 44F in addition to the first to third regions 41 to 43. The fourth region 44F surrounds the outer periphery of the second region 42, radially inward of the third region 43. The fourth region 44F has an annular shape. The fourth region 44F is in contact with both the second region 42 and the third region 43.

[0065] 7D to 7F, the power density q1 of the laser beam L irradiated to the first region 41, the power density q2 of the laser beam L irradiated to the second region 42, the power density q3 of the laser beam L irradiated to the third region 43, and the power density q4 of the laser beam L irradiated to the fourth regions 44D to 44F satisfy the relationships q1>q2, q3>q4. For example, these power densities q1 to q4 may satisfy the relationship q1>q3>q2>q4.

[0066] (6d) Irradiation area 40G shown in Fig. 7G includes third area 43G. An area in which at least one of the inner and outer circumferential edges in the radial direction meanders and the area as a whole extends in an arc shape, like third area 43G, is also an example of an area extending in an arc shape.

[0067] (6e) The shapes of the first to third regions are not limited to the shapes exemplified in the above embodiments. In the above embodiments, the first region 41 is a perfect circle, but the first region may be, for example, elliptical. In the above embodiments, the second region 42 is an annular shape with a perfect circle as its outer shape, but the second region may be an annular shape with an elliptical outer shape, for example. In the above embodiments, the third region 43 is an arc-shaped shape extending along the periphery of a perfect circle, but the third region may be an arc-shaped shape extending along the periphery of an ellipse, for example. Furthermore, for example, as in the irradiation region 40H shown in FIG. 7H, the third region 43H may be a shape other than an arc, extending along the periphery of the second region 42.

[0068] (6f) In the above embodiment, the third region 43 is not in contact with the second region 42. However, as shown in Figures 7G and 7H, the third regions 43G and 43H may be in contact with, for example, the second region 42. In other words, the third regions 43G and 43H may be continuous with, for example, the second region 42.

[0069] (6g) In the above embodiment, the robot arm 140 moves the optical head 130, thereby relatively moving the irradiation area 40. However, the means for realizing the relative movement of the irradiation area 40 is not particularly limited. For example, a known processing machine may be used instead of the robot arm 140, thereby relatively moving the irradiation area 40. Also, for example, a known galvanometer head may be used as the optical head 130, and the irradiation area 40 may be relatively moved by a reflecting mirror of the galvanometer head. Also, for example, when the first metal plate 10 and the second metal plate 20 are placed on a work table, the work table may move relative to the optical head 130, thereby relatively moving the irradiation area 40.

[0070] (6h) The function of one component in the above embodiments may be distributed among multiple components, or the functions of multiple components may be integrated into one component. Also, part of the configuration of the above embodiments may be omitted. Furthermore, at least part of the configuration of the above embodiments may be added to or substituted for the configuration of another of the above embodiments.

[0071] [Technical idea disclosed in this specification] [Item 1] A method for manufacturing a welded member, comprising: and forming the welded member by welding the first metal plate and the second metal plate together by irradiating a laser beam along the end surfaces of the first metal plate and the second metal plate while the end surfaces of the first metal plate and the second metal plate are butted against each other, The irradiation area, which is the area irradiated with the laser beam, is Relatively moving along the end surface, and a first region, a second region surrounding the outer periphery of the first region, and a third region that is a region located outside the second region and at least in front of the second region in a movement direction in which the illumination region moves relatively; In the movement direction, a rear end of the third region is located forward of a rear end of the second region, A method for manufacturing a welded member, wherein the power density q1 of the laser beam irradiated to the first region, the power density q2 of the laser beam irradiated to the second region, and the power density q3 of the laser beam irradiated to the third region satisfy the relationship q1>q2, q3.

[0072] [Item 2] A method for manufacturing a welded component according to item 1, A method for manufacturing a welded member, wherein a power density q1 of the laser beam irradiated to the first region, a power density q2 of the laser beam irradiated to the second region, and a power density q3 of the laser beam irradiated to the third region satisfy the relationship q1>q3>q2.

[0073] [Item 3] A method for producing a welded member according to item 1 or 2, A method for manufacturing a welded component, wherein the second region is in contact with the first region.

[0074] [Item 4] A method for producing a welded member according to any one of items 1 to 3, A method for manufacturing a welded component, wherein the irradiation area has a dimension in the movement direction that is smaller than a dimension in a direction perpendicular to the movement direction.

[0075] [Item 5] A method for producing a welded member according to any one of items 1 to 4, A method for manufacturing a welded member, wherein the thickness of the first metal plate is greater than the thickness of the second metal plate. [Explanation of symbols]

[0076] 10...First metal plate, 20...Second metal plate, 13,23...End face, 30...Welding member, 40,40A~40H...Irradiation area, 41...First area, 42,42C...Second area, 43,43A ,43B,43G,43H...Third region, 42x,43x...Front end, 42y,43y,43z...Back end, 44E~44F...Fourth region, 50...Weld pool, 60...Joint part, 100... Welding device, 110...laser oscillator, 120...optical fiber, 130...optical head, 131...collimating lens, 132...diffractive optical element, 133...focusing lens, 140...robot arm, 150...gas nozzle, C...center, G...gas, L...laser beam, M1, M3...length, M2, M4...width, X...arc, Y1...first virtual line, Y2...second virtual line.

Claims

1. A method for manufacturing a welded member, comprising: and forming the welded member by welding the first metal plate and the second metal plate together by irradiating a laser beam along the end surfaces of the first metal plate and the second metal plate while the end surfaces of the first metal plate and the second metal plate are butted against each other, The irradiation area, which is the area irradiated with the laser beam, is Relatively moving along the end surface, and a first region, a second region surrounding an outer periphery of the first region, and a third region located outside the second region and at least in front of the second region in a movement direction in which the illumination region moves relatively; In the movement direction, a rear end of the third region is located forward of a rear end of the second region, a power density q1 of the laser beam irradiated to the first region, a power density q2 of the laser beam irradiated to the second region, and a power density q3 of the laser beam irradiated to the third region satisfy the relationship q1 > q2, q3.

2. 2. The method for manufacturing a welded member according to claim 1, a power density q1 of the laser beam irradiated to the first region, a power density q2 of the laser beam irradiated to the second region, and a power density q3 of the laser beam irradiated to the third region satisfy the relationship q1 > q3 > q2.

3. The method for manufacturing a welded member according to claim 1 or 2, The second region is in contact with the first region.

4. The method for manufacturing a welded member according to claim 1 or 2, A method for manufacturing a welded component, wherein the irradiation area has a dimension in the movement direction that is smaller than a dimension in a direction perpendicular to the movement direction.

5. The method for manufacturing a welded member according to claim 1 or 2, A method for manufacturing a welded component, wherein the thickness of the first metal plate is greater than the thickness of the second metal plate.

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