Butt Welding Method

Abstract

To provide a butt welding method which can effectively suppress occurrence of a gap between metal plates.SOLUTION: A butt welding method is given in which respective side edges of a first workpiece W1 and a second workpiece W2 abutting on each other are inclined side edges 45, 55 inclining toward the other side workpiece W1, W2 while going along a welding direction. Welding is performed from one end of a welding range to the other end while the inclined side edges 45, 55 contact with unmovable restraint members 6, 7. Thereby, a force component of a reaction force works as a force toward the other side W1, W2 from the restraint members 6, 7 against force which causes elongation along the welding direction by the effect of weld heat. The force works in a direction opposite to gap occurrence force so that a gap therebetween can be effectively suppressed.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a butt welding method, and more particularly to a measure for suppressing a gap occurring between butted portions of metal plates, that is, a gap between the butted portions of metal plates. [Background technology]

[0002] Conventionally, butt welding has been known as a method for welding metal plates together. In this butt welding, edges of metal plates are butted together and the butt portion is welded from one end to the other end, as disclosed in, for example, Patent Document 1. Also, as the method of this butt welding, laser welding, arc welding, and laser-arc hybrid welding, which is a combination of these welding methods, are known. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-5771 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the butt welding of metal plates, when welding from one end of the butt joint to the other end, welding heat accumulates in the metal plates, which can cause deformation of the metal plates. In particular, the welded portion rapidly shrinks as it cools after thermal expansion, which can cause the butt joint to recede from the mating metal plate in the unwelded portion (the portion on the other end side of the welded portion), resulting in a so-called opening (a state in which a relatively large gap occurs between the butt joints), which can adversely affect the butt welding and can cause poor appearance quality and internal defects.

[0005] As a means for suppressing the occurrence of gaps between the butted parts of the metal plates, it is possible to use a restraining member that restrains the deformation of each metal plate in a direction perpendicular to the opening direction. Figure 7 shows that the outward deformation of each metal plate a, b is restricted by arranging restraining members c, d having edges perpendicular to the opening direction on both outer edges of each metal plate a, b.

[0006] However, with this configuration, it is difficult to obtain a restraining force sufficient to sufficiently suppress the gap between the metal plates a and b, and there remains a possibility that local deformation will occur at the butted portion, causing the gap to occur.

[0007] The present invention has been made in consideration of the above points, and an object of the present invention is to provide a butt welding method that can enhance the effect of suppressing the occurrence of gaps between metal plates. [Means for solving the problem]

[0008] The solution of the present invention to achieve the above object is as follows: The weld edge has a first edge extending in one direction and a second edge extending in a direction inclined from one end of the first edge in the extension direction to a direction in which the included angle between the first edge and the second edge is an obtuse angle. A first metal plate; The welded edge includes a third edge that is butt-welded to the first edge of the first metal plate, and a fourth edge that is butt-welded to the second edge of the first metal plate. A second metal plate; The first edge and the third edge are butted together, and the second edge and the fourth edge are butted together, and in the welding range formed by butting these edges together, a welding start end on the opposite side to the one end of the first edge in the welding range between the first edge and the third edge, and a welding end end on the opposite side to the one end of the first edge in the welding range between the second edge and the fourth edge are The butt welding method is based on the premise that welding is performed along the welding direction toward the front. Record number In the metal plate of 2, the welding area Welding End Against In the welding area between the second edge and the fourth edge Located in a direction perpendicular to the welding direction The side The edge is, The Along the welding direction The first metal plate and the inclined side edge is inclined toward the immovable restraining member, From the welding start end to the welding end The welding is carried out toward the target.

[0009] This specification allows the welding range at the butt joint of metal plates to be Weld start point from Welding EndWhen welding is performed along the welding direction toward the welded portion, the welding heat not only causes a force that causes deformation (opening) in a direction perpendicular to the welding direction to act on the unwelded portions of each metal plate, but also causes a force that causes elongation in the direction along the welding direction. In the second metal plate, a side edge located on the side of the welding end end of the welding area perpendicular to the welding direction in the welding area between the second edge and the fourth edge As it moves in the direction along the welding direction, First metal plate Since the inclined side edges are in contact with the restraining members, a component of the reaction force from the restraining members to the force causing the elongation acts on the metal plate as a force toward the mating metal plate. This force (component of the force toward the mating metal plate) acts in the opposite direction to the force causing the opening, and therefore the opening can be effectively suppressed. Effect of the Invention

[0010] In the present invention, In the second metal plate, a welding end portion is provided between the second edge and the fourth edge of the welding area, the welding end portion being located on a side perpendicular to the welding direction. As the side edge moves in the direction along the welding direction First metal plate and a state in which the inclined side edge is in contact with an immovable restraining member, Weld start point from Welding End As a result, a component of the reaction force from the restraining member against the force that causes elongation in the direction along the welding direction due to the influence of welding heat acts on the metal plate as a force toward the mating metal plate, and this force acts in the opposite direction to the force that causes the separation, making it possible to effectively suppress the separation. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic diagram showing a state in which welding is being performed by a laser-arc hybrid welding apparatus in an embodiment. FIG. [Diagram 2] FIG. 2 is a plan view showing the arrangement of the workpieces on the workbench, illustrating the state during welding. [Diagram 3] FIG. 1 is a diagram showing the results of an experiment conducted to confirm the effects of the present invention. [Figure 4]FIG. 1 is a side view of a vehicle body frame for explaining an example in which the present invention is applied to butt welding of a vehicle body frame. [Diagram 5] FIG. 3 is a view equivalent to FIG. 2 in modified example 1. [Figure 6] FIG. 11 is a view equivalent to FIG. 2 in a second modified example. [Figure 7] 2 and shows an example in which restraining members having edges perpendicular to the opening direction are arranged on both outer edges of each metal plate. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In this embodiment, a case where workpieces (metal plates) having different thicknesses are butt-welded by laser-arc hybrid welding will be described as an example.

[0013] Fig. 1 is a schematic diagram showing a state in which welding is being performed by a laser-arc hybrid welding apparatus (hereinafter simply referred to as a welding apparatus) 1 according to this embodiment. As shown in Fig. 1, the welding apparatus 1 includes an arc welding apparatus 2 for performing arc welding and a laser welding apparatus 3 for performing laser welding.

[0014] In this embodiment, the workpieces W1 and W2 to be welded by the welding device 1 are different in thickness and are butt-welded by the welding device 1. In the following description, the workpiece having a larger thickness (the workpiece on the far side in FIG. 1) is called the first workpiece (the first metal plate in the present invention) W1, and the workpiece having a smaller thickness (the workpiece on the near side in FIG. 1) is called the second workpiece (the second metal plate in the present invention) W2. As shown in FIG. 1, the near side edge (welding edge) 41 of the first workpiece W1 and the far side edge (welding edge) 51 of the second workpiece W2 are welded (butt-welded) by the welding device 1 in a state where they are butted against each other.

[0015] The arc welding device 2 and the laser welding device 3 will be described below.

[0016] -Arc welding equipment- The arc welding device 2 includes a welding power supply 21, a wire feeder 22, and an arc torch (welding torch) 23.

[0017] Welding power supply 21 receives an AC commercial power supply (not shown), such as a three-phase 200V power supply, and performs output control such as inverter control to output a welding voltage Vw and a welding current Iw for generating an arc plasma AP. Welding power supply 21 outputs a feed control signal Fc to feeder 22. Note that the configuration of welding power supply 21 is not limited to this.

[0018] Feeder 22 receives a feed control signal Fc from welding power supply 21 and feeds arc wire (welding wire) 24 from arc torch 23 at a predetermined feed speed in accordance with the feed control signal Fc.

[0019] The arc torch 23 feeds power to the arc wire 24 via an attached power feed tip (not shown) and sends the arc wire 24 toward the welding portion (butt portion) of the workpieces W1 and W2. As a result, an arc plasma AP is generated by arc discharge between the arc wire 24 and each of the workpieces W1 and W2.

[0020] In the example shown in FIG. 1, the arc torch 23 is positioned so that the incidence angle of the arc wire 24 is about 60°, but this is not limiting.

[0021] Although not shown, the arc welding device 2 may be provided with a shielding gas supplying means for supplying a shielding gas to the welding portions of the workpieces W1, W2.

[0022] -Laser welding equipment- The laser welding device 3 includes a laser oscillator 31 , an optical fiber 32 , and a laser torch 33 .

[0023] The laser oscillator 31 outputs a laser beam LB for performing laser welding.

[0024] The optical fiber 32 is for guiding the laser light LB to the laser torch 33 .

[0025] The laser torch 33 focuses the light by various built-in optical systems (not shown), and irradiates the laser light LB onto the welding site (butted portion) of the workpieces W1 and W2.

[0026] In this embodiment, the laser beam LB is positioned so as to be perpendicular to the welding area. That is, the incident angle of the laser beam LB is set to about 90°. The incident angle is not limited to this.

[0027] In this embodiment, the arc welding device 2 is disposed downstream (left side in FIG. 1) in the welding direction (see arrow Y in FIG. 1) of the laser welding device 3. That is, during welding, arc welding is performed first and laser welding is performed second in the welding direction from one end (right end in FIG. 1) to the other end (left end in FIG. 1) of the welding range at the butt joint between the workpieces W1 and W2.

[0028] The arc torch 23 of the arc welding apparatus 2 and the laser torch 33 of the laser welding apparatus 3 described above are attached to the tip of a robot arm of a welding robot (not shown) with their relative positions determined relative to each other, and as the robot arm operates, they are moved along the welding direction from one end of the welding range at the butt joint between the workpieces W1 and W2 (see arrow Y in FIG. 1).

[0029] Generally, laser-arc hybrid welding involves moving the position where the arc plasma AP is formed by arc discharge (the position on the workpieces W1, W2 where the arc plasma AP is emitted) and the irradiation position of the laser light LB along the weld line (the weld line defined by the butt joint between the workpieces W1, W2, etc.) to weld the workpieces W1, W2 together, and therefore has the advantages of both arc welding and laser welding, and is known for its high tolerance for gap management and deep penetration.

[0030] -Workpiece shape and restraining materials- Next, the shapes of the workpieces W1 and W2, which are features of this embodiment, and the restraining members 6 and 7 for positioning the workpieces W1 and W2 will be described.

[0031] FIG. 2 is a plan view showing the arrangement of the workpieces W1 and W2 on the worktable 11 during laser-arc hybrid welding, and shows the state during welding (a state in which welding has been completed up to the circle mark at the butt joint in FIG. 2). As shown in FIG. 2, each workpiece W1 and W2 is made of a pentagonal member in a plan view. Here, the left-right direction in FIG. 2 is defined as the x direction, the left direction in FIG. 2 is called the x1 direction, and the right direction is called the x2 direction. The up-down direction in FIG. 2 is defined as the y direction, the up direction in FIG. 2 is called the y1 direction, and the down direction is called the y2 direction. This y1 direction coincides with the welding direction described above (the arrow Y direction in FIG. 1).

[0032] The outer edge shape of the first workpiece W1 is such that, when the first workpiece W1 is placed on the workbench 11, the welded edge 41, which is the butted portion, extends along the y direction. The welded edge 41 has a leading edge 42 extending in the x2 direction from the edge on the y1 direction side, and a trailing edge 43 extending in the x2 direction from the edge on the y2 direction side of the welded edge 41. The first workpiece W1 also has an outer edge 44 extending in the y1 direction from the edge on the x2 direction side of the trailing edge 43. The outer edge shape of the first workpiece W1 is characterized by an inclined side edge 45 connecting the leading edge 42 (the edge on the x2 direction side of the leading edge 42) and the outer edge 44 (the edge on the y1 direction side of the outer edge 44). Therefore, the inclined side edge 45 is configured as a side edge (inclined side edge) located on the side of the first workpiece W1 in a direction perpendicular to the welding direction with respect to the other end of the welding range. The inclination angle of the inclined side edge 45 can be set arbitrarily. In this embodiment, the angle is set to 45°. With this configuration, the outer edge 44 and the inclined side edge 45 constitute the side edge referred to in the present invention, and this side edge is configured to include the inclined side edge 45 (the inclined side edge that inclines toward the mating metal plate as it moves in the direction along the welding direction).

[0033] The outer edge shape of the second workpiece W2 is symmetrical to that of the first workpiece W1. Specifically, when the second workpiece W2 is placed on the workbench 11, the welded edge 51, which is the butted portion, extends along the y direction. The second workpiece W2 also has a leading edge 52 extending in the x1 direction from the edge on the y1 direction side of the welded edge 51, and a trailing edge 53 extending in the x1 direction from the edge on the y2 direction side of the welded edge 51. The second workpiece W2 also has an outer edge 54 extending in the y1 direction from the edge on the x1 direction side of the trailing edge 53. The outer edge shape of the second workpiece W2 is characterized by an inclined side edge 55 connecting the leading edge 52 (the edge on the x1 direction side of the leading edge 52) and the outer edge 54 (the edge on the y1 direction side of the outer edge 54). Therefore, the inclined side edge 55 is configured as a side edge (inclined side edge) located on the side perpendicular to the welding direction with respect to the other end of the welding range in the second workpiece W2. The inclination angle of the inclined side edge 55 can be set arbitrarily. In this embodiment, it is set to 45°. With this configuration, the outer edge 54 and the inclined side edge 55 constitute the side edge according to the present invention, and this side edge is configured to include the inclined side edge 55.

[0034] Then, restraining members 6, 7 that come into contact with each of the workpieces W1, W2 are fixed onto the workbench 11. Here, the restraining member 6 that comes into contact with the first workpiece W1 is referred to as the first restraining member 6, and the restraining member 7 that comes into contact with the second workpiece W2 is referred to as the second restraining member 7. Means for fixing these restraining members 6, 7 onto the workbench 11 (fixing them so that they cannot move) include bolting, welding, and the like.

[0035] The first restraining member 6 has a rectangular shape in a plan view and a restraining edge 61 that abuts against the inclined side edge 45 of the first work W1. The restraining edge 61 extends along the extension direction of the inclined side edge 45 so that the entire restraining edge 61 abuts against the inclined side edge 45. That is, the restraining edge 61 has an inclination angle of 45° with respect to the x direction and the y direction. In this embodiment, the length of the restraining edge 61 is approximately equal to the length of the inclined side edge 45. Therefore, the position of the end of the restraining edge 61 on the y1 direction side is approximately equal to the position of the connection part between the tip edge 42 of the first work W1 and the inclined side edge 45. In addition, the position of the end of the restraining edge 61 on the y2 direction side is approximately equal to the position of the connection part between the outer edge 44 of the first work W1 and the inclined side edge 45. The length of the restraining edge 61 is not limited to this, and may be set longer than the length of the inclined side edge 45.

[0036] The second restraining member 7 has a shape symmetrical to the first restraining member 6. Specifically, the second restraining member 7 has a rectangular shape in a plan view and has a restraining edge 71 that abuts against the inclined side edge 55 of the second work W2. The restraining edge 71 extends along the extension direction of the inclined side edge 55 so that the entire restraining edge 71 abuts against the inclined side edge 55. That is, the restraining edge 71 has an inclination angle of 45° with respect to the x direction and the y direction. In addition, in this embodiment, the length dimension of the restraining edge 71 is approximately the same as the length dimension of the inclined side edge 55. Therefore, the position of the end of the restraining edge 71 on the y1 direction side is approximately the same as the position of the connection part between the tip edge 52 of the second work W2 and the inclined side edge 55. In addition, the position of the end of the restraining edge 71 on the y2 direction side is approximately the same as the position of the connection part between the outer edge 54 of the second work W2 and the inclined side edge 55. The length dimension of the restraining edge 71 is not limited to this, and may be set longer than the length dimension of the inclined side edge 55.

[0037] -Welding operation- Next, the welding operation will be described. Prior to this welding operation, each workpiece W1, W2 is placed on the worktable 11. As described above, the workpieces W1, W2 are placed on the worktable 11 in such a manner that the welded edges 41, 51 of the workpieces W1, W2 are butted against each other, the inclined side edge 45 of the first workpiece W1 is abutted against the restraining edge 61 of the first restraining member 6, and the inclined side edge 55 of the second workpiece W2 is abutted against the restraining edge 71 of the second restraining member 7. As a result, each workpiece W1, W2 is placed on the worktable 11 in a state of being restrained by each restraining member 6, 7. If necessary, a restraining member (not shown) may be provided to restrain the position of the rear end edge 43, 53 of each workpiece W1, W2.

[0038] Then, when the welding operation is started, as the robot arm operates, the arc welding device 2 and the laser welding device 3 move along the welding direction from one end of the welding range at the butt joint between the workpieces W1, W2 on the y2 side to the other end on the y1 side, welding the butt joint between the workpieces W1, W2 by melting them with the arc plasma AP and laser light LB (welding sequentially from one end of the welding range at the butt joint to the other end).

[0039] When welding is performed from one end of the welding range to the other end, due to the influence of the welding heat, in the parts of each workpiece W1, W2 that have not yet been welded, not only a force that causes deformation (to cause opening) in a direction perpendicular to the welding direction (see arrow A in FIG. 2) but also a force that causes elongation in a direction along the welding direction (see arrow B in FIG. 2) acts. As described above, since each inclined side edge 45, 55 of each workpiece W1, W2 is abutted against the restraining edges 61, 71 of the restraining members 6, 7, a component of the reaction force (see the arrow indicated by the broken line) from the restraining members 6, 7 against the force that causes this elongation (arrow B) acts on each workpiece W1, W2 as a force toward the other workpiece W1, W2 (see arrow C in FIG. 2). Since this force (component force toward the other workpiece W1, W2) acts in the opposite direction to the force that causes the opening, this opening can be effectively suppressed. As a result, the butt welding can be performed well, the appearance quality can be improved, and internal defects can be suppressed.

[0040] -Experimental example- An example of an experiment conducted to confirm the effect of the above-mentioned welding method will be described. In this experiment, the amount of opening of each workpiece W1, W2 (a, b) over time was measured when laser-arc hybrid welding was performed on a workpiece in which the restraining members c, d (restraining members having edges perpendicular to the opening direction) shown in Fig. 7 were arranged as a reference example, and on a workpiece in which the inclined side edges 45, 55 of each workpiece W1, W2 were abutted against the restraining edges 61, 71 of the restraining members 6, 7 as in the above-mentioned embodiment.

[0041] Fig. 3 is a diagram showing the experimental results. The horizontal axis in Fig. 3 is the time elapsed from the start of welding, and the vertical axis is the opening amount (the opening amount at the leading edges 42, 52 of each workpiece W1, W2), with the opening amount increasing downward. As is clear from Fig. 3, the opening amount is significantly large at timing t1 in the reference example. In contrast, the opening amount in the embodiment is significantly smaller than that in the reference example. This confirms the effect of the welding method according to the embodiment.

[0042] -Example of application to butt welding of vehicle body frames- Next, an example of the application of the above-mentioned butt welding method to butt welding of a vehicle body frame will be described. Fig. 4 is a side view of a vehicle body frame 8 for explaining an example of the application of the butt welding method according to the present invention to butt welding of a vehicle body frame 8.

[0043] The vehicle body frame 8 according to this example is produced by welding three members. Specifically, a second member 82 and a third member 83 are butt-welded to both sides (top and bottom sides in FIG. 4) of a first member 81.

[0044] The present invention is applied to the butt welding of the first member 81 and the third member 83. Specifically, the weld edge 81a of the first member 81 includes a horizontal edge 81b extending substantially in the left-right direction in Fig. 4, and an inclined edge 81c inclined downward from one end of the horizontal edge.

[0045] On the other hand, the welding edge 83a of the third member 83 includes a horizontal edge 83b that is butt-welded to the horizontal edge 81b of the first member 81, and an inclined edge 83c that is butt-welded to the inclined edge 81c. The angle between the inclined edge 83c and the outer surface (the lower surface in FIG. 4) 83d of the third member 83 is an acute angle. This configuration corresponds to the configuration in the present invention where "the side edge located on the side in the direction perpendicular to the welding direction with respect to the other end of the welding range includes an inclined side edge that inclines toward the mating metal plate as it moves along the welding direction." The restraining member 6 is abutted against the outer surface 83d of the third member 83 near the connection portion between the outer surface 83d and the inclined edge 83c. This configuration corresponds to the configuration in the present invention where "the inclined side edge is abutted against an immovable restraining member."

[0046] During butt welding of the first member 81 and the third member 83, the butt portions of the horizontal edges 81b, 83b are welded as shown by the dashed arrows in FIG. 4, and then the butt portions of the inclined edges 81c, 83c are welded. When the butt portions of the inclined edges 81c, 83c are welded, due to the influence of the welding heat, in the parts of the first member 81 and the third member 83 that have not yet been welded, not only a force that causes deformation (opening) in a direction perpendicular to the welding direction acts, as in the case described above, but also a force that causes elongation in a direction along the welding direction (see arrow B in FIG. 4). Since the outer surface 83d of the third member 83 is in contact with the restraining member 6, a component of the reaction force from the restraining member 6 against the force that causes this elongation (arrow B) acts on the third member 83 as a force toward the first member 81. Since this force acts in the opposite direction to the force that causes the opening, this opening can be effectively suppressed. As a result, the butt welding can be performed well, the appearance quality can be improved, and internal defects can be suppressed.

[0047] -Variations- Next, modified examples will be described. The modified examples described below differ from the above-described embodiment in the shape of each workpiece W1, W2 and the state of restraint of each workpiece W1, W2 by the restraining member. Since the other configurations are the same as the above-described embodiment, only the differences from the above-described embodiment in the shape of each workpiece W1, W2 and the state of restraint of each workpiece W1, W2 by the restraining member will be described here.

[0048] Fig. 5 is a view equivalent to Fig. 2 in Modification 1. As shown in Fig. 5, in this example, the present invention is applied only to the first workpiece W1. That is, the first workpiece W1 is provided with an inclined side edge 45 on its outer edge, and the inclined side edge 45 is in contact with the restraining edge 61 of the first restraining member 6.

[0049] In addition, the second workpiece W2 is rectangular in shape, and the outer edge 56 of the second workpiece W2 is abutted against the edge 91 of the restraining member 9, which has an edge 91 perpendicular to the opening direction, to restrict outward deformation of the second workpiece W2.

[0050] The configuration of this example can also achieve the same effects as those of the above-described embodiment. That is, since the inclined side edge 45 of the first workpiece W1 is in contact with the restraining edge 61 of the restraining member 6, a component force (arrow C) of the reaction force from the restraining member 6 against the force (arrow B) that causes the stretching acts on the first workpiece W1 as a force toward the second workpiece W2. Since this force (arrow C) acts in the opposite direction to the force that causes the opening, the opening can be effectively suppressed.

[0051] Fig. 6 is a view equivalent to Fig. 2 in modified example 2. As shown in Fig. 6, in this example, the entire outer edge of each of the workpieces W1, W2 is configured as an inclined side edge 45, 55. Then, each of the restraining members 6, 7 abuts against the inclined side edge 45, 55 over a predetermined range from the end edge on the y1 direction side of the inclined side edge 45, 55 of each of the workpieces W1, W2.

[0052] The configuration of this example can achieve the same effect as in the above-mentioned embodiment. That is, since the inclined side edges 45, 55 of the workpieces W1, W2 are in contact with the restraining edges 61, 71 of the restraining members 6, 7, a component of the reaction force from the restraining members 6, 7 to the force causing the extension (arrow B) acts on each workpiece W1, W2 as a force (arrow C) toward the other workpiece W1, W2. Since this force acts in the opposite direction to the force causing the opening, the opening can be effectively suppressed.

[0053] -Other embodiments- The present invention is not limited to the above-described embodiment and each of the modifications, and all modifications and applications encompassed within the scope of the claims and equivalents thereto are possible.

[0054] For example, in the above embodiment and each of the above modified examples, a case has been described in which laser-arc hybrid welding is applied to butt welding of workpieces W1 and W2 having different thickness dimensions. The present invention is not limited to this, and can also be applied to butt welding of workpieces having the same thickness dimensions. Furthermore, the butt welding method is not limited to laser-arc hybrid welding, and laser welding or arc welding can also be applied.

[0055] In addition, in the above embodiment, arc welding is performed first and laser welding is performed second, but this is not limiting, and laser welding may be performed first and arc welding may be performed second.

[0056] In the above embodiment, the workpieces W1, W2 arranged extending in the horizontal direction are subjected to arc welding by the arc welding device 2 and laser welding by the laser welding device 3 from above. The arrangement of the workpieces W1, W2 and the welding direction are not limited to this, and for example, the workpieces W1, W2 arranged extending in the vertical direction may be subjected to arc welding by the arc welding device 2 and laser welding by the laser welding device 3 from the horizontal direction. [Industrial Applicability]

[0057] The present invention is applicable to a butt welding method that suppresses the occurrence of gaps between butted portions of metal plates. [Explanation of symbols]

[0058] 1 Welding equipment 41,51 Welding edge (butt joint) 45,55 Sloped side edge 6 First restraining member 7 Second restraining member W1 First workpiece (first metal plate) W2 Second workpiece (second metal plate)

Claims

[Claim 1] A first metal plate having a weld edge, the first edge extending in one direction, and a second edge extending from one end of the first edge in the extension direction at an incline in a direction such that the included angle between the first edge and the second edge is an obtuse angle; a second metal plate having, as weld edges, a third edge that is butt-welded to the first edge of the first metal plate and a fourth edge that is butt-welded to the second edge of the first metal plate, a butt welding method in which the first edge and the third edge are butted together and the second edge and the fourth edge are butted together, and welding is performed along a welding direction from a welding start end on an opposite side to the one end of the first edge in the welding area between the first edge and the third edge to a welding end end on an opposite side to the one end of the first edge in the welding area between the second edge and the fourth edge, a butt welding method characterized in that in the second metal plate, a side edge located in a direction perpendicular to the welding direction in the welding range between the second edge and the fourth edge relative to the welding end end of the welding range includes an inclined side edge that inclines toward the first metal plate as it proceeds in the direction along the welding direction, and welding is performed from the welding start end toward the welding end end with the inclined side edge abutted against an immovable restraining member.

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