JP2015229171A - Laser-arc hybrid welding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser arc hybrid welding method welding bonded surfaces of two long workpieces that are large-sized structures and capable of making uniform bond strength along a longitudinal direction while suppressing an increase in equipment cost.SOLUTION: Provided is a laser-arc hybrid welding method for confronting bonded surfaces 1a and 2a of two long steel members 1 and 2 that are large-sized structures and face against each other, and continuously welding together the bonded surfaces 1a, 2a in a longitudinal direction by means of laser welding and arc welding. During the arc welding, only portions of the bonded surfaces 1a and 2a in which arc is generated in a welding depth direction are welded together by an arc molten portion 32. During the laser welding, an emitted laser beam 22 is inclined from a reference axis K1 extending in the welding depth direction toward an orthogonal axis T1 of the bonded surfaces 1a and 2a, and only portions of the bonded surfaces 1a and 2a in the welding depth direction are welded together by a laser molten portion 23.

Description

  The present invention relates to a laser arc hybrid welding method in which laser welding and arc welding are used for welding joining, and in particular, the joining surfaces of two long workpieces which are large structures are welded to each other, and the joining strength thereof. The present invention relates to a laser arc hybrid welding method capable of making the workpiece substantially uniform along the longitudinal direction of the workpiece.

  In recent years, a laser arc hybrid welding method has started to be applied as a welding method for large structures, and is described, for example, in Patent Document 1 below. This laser arc hybrid welding method is attracting attention as a welding method that makes use of the advantages of laser welding and arc welding while complementing those disadvantages.

  Laser welding has the advantages of low heat input, low distortion, and high speed welding. Moreover, since deep penetration can be performed, it is applicable to a thick plate member. However, since the width of the laser beam is narrow, there is a demerit that if the gap formed between the joining surfaces is large, the laser melting portion cannot be formed accurately. That is, the margin for the gap is small.

  On the other hand, arc welding has the advantage that the apparatus is relatively inexpensive, has a large technical accumulation, and is highly reliable. Moreover, since the arc melting part is wide, the margin with respect to the gap is large. However, since the heat input is higher than that of laser welding, there is a demerit that the distortion of the arc melting portion is large. Furthermore, since deep penetration cannot be performed, it is difficult to apply to thick plate members.

  Thus, the laser arc hybrid welding method can obtain the merits of low heat input, low distortion, high accuracy, and high speed welding by using both laser welding and arc welding. Further, deep penetration can be performed and the margin for the gap can be increased. FIG. 12 is a perspective view showing a state in which the joining surfaces 101a and 102a of two butted plate-like members 101 and 102 are welded together by conventional laser arc hybrid welding.

  As shown in FIG. 12, a laser irradiation head 121 irradiates a laser beam 122 toward each bonding surface 101a, 102a to form a substantially linear laser melting portion 123. At this time, as shown in FIG. 13A, the laser beam 122 is irradiated in a direction orthogonal to the plate-like members 101 and 102 so as to pass through the entire bonding surfaces 101a and 102a. In addition, an arc is generated between the front end portion of the arc torch 131 and the upper surfaces of the plate-like members 101 and 102 to form an arc melting portion 132 having a substantially semicircular shape on the lower side.

  In this way, as shown in FIG. 13B, the laser melting part 123 and the arc melting part 132 are mixed to form a weld bead, and the joining surfaces 101a and 102a are welded together. Since the laser irradiation head 121 and the arc torch 131 move in the longitudinal direction of the plate-like members 101 and 102 (the direction indicated by the arrow in FIG. 12), the joining surfaces 101a and 102a are continuously welded and joined in the longitudinal direction. The

JP 2013-711146 A

  However, when the joining surfaces of two long workpieces which are large structures are welded together, the conventional laser arc hybrid welding method has the following problems. That is, a manufacturing error always occurs in a long work (plate-like members 101 and 102) extending to several tens of meters. Further, when placing a work that is a large structure, the work may be bent by its own weight. Due to these manufacturing errors and bending of the workpiece, the joining surfaces 101a and 102a are displaced from the specified position in the width direction (left and right direction in FIG. 12) according to the position in the longitudinal direction of the plate-like members 101 and 102. There is a possibility that a gap larger than the width of the laser beam 122 may be generated between 102a.

  As shown in FIG. 14A, when the joining surfaces 101a and 102a are displaced in the width direction from the specified position P2, the laser beam 122 does not pass through the joining surfaces 101a and 102a, and one plate-like member 102 is present. Only the laser melting portion 123a is formed. Thereby, as shown in FIG. 14B, a weld bead is formed by the laser melting portion 123a and the arc melting portion 132a, and the joining length h1 of the joining surfaces 101a and 102a is shortened. Further, as shown in FIG. 15A, if a gap 103 larger than the width of the laser beam 122 is generated between the bonding surfaces 101a and 102a, the laser beam 122 passes through the gap 103, and the laser melting portion. Is not formed. Accordingly, as shown in FIG. 15B, only the weld bead is formed by the arc melting portion 132b, and the joining length h2 of the joining surfaces 101a and 102a is shortened.

  As a result, depending on the position of the plate-like members 101 and 102 in the longitudinal direction, there is a problem that a part having a long joining length or a part having a short joining length is generated and the joining strength is not uniform. In other words, there is a large margin (acceptable range) in order to absorb misalignment and large gaps in the joint surface in order to accurately weld and join the joint surfaces of long workpieces in the longitudinal direction. Although necessary, the conventional laser arc hybrid welding method has a problem that a large margin cannot be secured.

  For the above problems, the laser light irradiation position is automatically controlled using a high-precision copying apparatus equipped with a camera and various sensors so that the laser light can accurately grasp the position of each joint surface. There is a way. However, this method complicates the structure and greatly increases the equipment cost. On the other hand, there is a method of increasing the laser output to thicken the weld bead so as to cope with a large gap. However, this method loses the advantages of low heat input and low distortion of laser arc hybrid welding.

  Further, there is a method of weaving the laser beam in a wave shape with respect to the traveling direction in order to thicken the weld bead. However, this method impairs the merit of high-speed welding of laser arc hybrid welding, and increases the equipment cost due to the addition of a mechanism for weaving laser light. Thus, there is a need for a laser arc hybrid welding method that can cope with the above-mentioned problems while suppressing an increase in equipment cost without significantly changing the conventional mechanism.

  Therefore, the present invention has been made to solve the above-described problems, and while suppressing an increase in equipment cost, the joining surfaces of two long workpieces that are large structures are welded together, It is an object of the present invention to provide a laser arc hybrid welding method capable of making the joint strength uniform along the longitudinal direction.

  In the laser arc hybrid welding method according to the present invention, the joining surfaces of two long workpieces which are large structures are made to face each other, and the joining surfaces are arranged in the longitudinal direction of the joining surfaces by laser welding and arc welding. In the arc welding, in the arc welding, only the portion on the side where the arc is generated in the welding depth direction is joined by the arc melting portion among the joining surfaces, and in the laser welding, irradiation is performed. The laser beam to be tilted from the reference axis extending in the welding depth direction toward the orthogonal axis of the joining surface, and only a part of the welding depth direction among the joining surfaces is joined by the laser melting portion. It is characterized by.

  According to the laser arc hybrid welding method according to the present invention, the laser beam is irradiated with being inclined so as to intersect the joint surface. For this reason, even if a joining surface has shifted | deviated to the direction (width direction) orthogonal to a joining surface from a prescription | regulation position, a laser melting part is formed in any one part of the welding depth direction among joining surfaces. Further, even if a large gap is generated between the joining surfaces, a laser melting portion is formed in any part of the joining surfaces in the welding depth direction. In this way, even if there is a positional deviation or a large gap between the joining surfaces, the position of the laser melting portion is only slightly moved up and down, and the joining length by the laser melting portion is substantially constant on the joining surface. On the other hand, in arc welding, an arc melting part is formed on the side where the arc is generated in the welding depth direction among the joint surfaces. Since the arc melting part is wide, the joining length by the arc melting part is almost constant even if the position of the joining surface is displaced or a large gap is generated.

  Thereby, the total length of the joining length by the laser melting part and the joining length by the arc melting part becomes substantially uniform along the longitudinal direction of the joining surface. As a result, when the joining surfaces of the two long workpieces are welded together, the joining strength can be made uniform along the longitudinal direction. In order to tilt the laser beam as described above, for example, only a mechanism for tilting the laser irradiation head is provided, and it is not necessary to significantly change the conventional apparatus. Therefore, it can be carried out while suppressing an increase in equipment cost.

In the laser arc hybrid welding method according to the present invention, it is preferable that the arc melting portion and the laser melting portion are separated from each other in the welding depth direction on the joining surface.
In this case, even if the joint surface deviates from the specified position to one side and the other side in the direction orthogonal to the joint surface, the laser melting portion and the arc melting portion do not coexist on the joint surface, and the laser Both the joining length by the melting part and the joining length by the arc melting part can be reliably ensured. In other words, even if the joint surface deviates from the specified position in the direction perpendicular to the joint surface, it is possible to prevent the laser melted portion and the arc melted portion from being mixed and prevent the joint length from being shortened. it can.

In the laser arc hybrid welding method according to the present invention, the arc melting portion and the laser melting portion may be integrated on the joining surface.
In this case, since the laser melting part and the arc melting part coexist on the joining surface, the total length of the joining length by the laser melting part and the joining length by the arc melting part becomes short. However, as described above, compared to the case where the arc melting portion and the laser melting portion are separated from each other in the welding depth direction on the joint surface, the amount of displacement of the joint surface in the direction orthogonal to the joint surface can be greatly tolerated. A larger margin can be secured.

In the laser arc hybrid welding method according to the present invention, the two workpieces may be a cylindrical member and a rod member welded to the outer peripheral surface of the cylindrical member.
In this case, a long cylindrical member having a large structure is greatly affected by manufacturing errors and bending as compared with, for example, a plate-like member. For this reason, when the rod member is welded to the outer peripheral surface of the cylindrical member, a misalignment of the joining surface and a large gap are likely to occur. Therefore, even under such severe conditions, the joining strength can be made uniform along the longitudinal direction by using the laser arc hybrid welding method according to the present invention.

  According to the laser arc hybrid welding method of the present invention, while suppressing an increase in equipment cost, the joining surfaces of two long workpieces that are large structures are welded together to increase the joining strength along the longitudinal direction. It can be made uniform. That is, even if a positional deviation or a large gap occurs on the bonding surface, the positional deviation or a large gap on the bonding surface can be absorbed. Therefore, it is a method that can ensure a large margin (acceptable range), and can be effectively used as a welding method for large structures.

It is the perspective view which showed the state by which the joint surface of each steel member was laser-arc hybrid welded in 1st Embodiment. It is a figure for demonstrating the inclination of a laser beam. It is a figure for demonstrating the welding conditions of 1st Embodiment. It is the figure which showed the state in which laser arc hybrid welding is carried out in the condition which the joining surface has shifted | deviated from the regulation position to the one side of the width direction. It is the figure which showed the state by which laser arc hybrid welding is carried out in the condition which the joining surface has shifted | deviated from the regulation position to the other side of the width direction. It is the figure which showed the state in which laser arc hybrid welding is carried out in the condition where the clearance gap larger than the width | variety of a laser beam is formed between the joining surfaces. It is a figure for demonstrating the relationship between joining length and margin with respect to the angle which inclines a laser beam. It is a figure for demonstrating the welding conditions of 2nd Embodiment. It is a figure for demonstrating the effect of 2nd Embodiment. It is sectional drawing which showed the relationship between an outer kelly bar and a drive shaft. It is the figure which expanded the Z part of FIG. It is a perspective view for demonstrating the conventional laser arc hybrid welding method. It is the figure which showed the ideal state by which the joint surface is weld-joined by the conventional laser arc hybrid welding method. It is the figure which showed the state weld-joined by the conventional laser arc hybrid welding method in the condition which the joining surface has shifted | deviated to the width direction from the regulation position. It is the figure which showed the state weld-joined by the conventional laser arc hybrid welding method in the condition where the clearance gap larger than the width | variety of a laser beam is formed between the joining surfaces.

<First Embodiment>
Embodiments of the laser arc hybrid welding method according to the present invention will be described with reference to the drawings. In 1st Embodiment shown below, the long steel members 1 and 2 are faced | matched in the width direction, and the joining surfaces 1a and 2a of each steel member 1 and 2 are laser arc hybrid-welded. .

  FIG. 1 is a perspective view showing a state in which the joining surfaces 1a and 2a of the steel members 1 and 2 are laser-arc hybrid welded, and particularly where the gap 3 is generated between the joining surfaces 1a and 2a. (Gap part) is shown. As shown in FIG. 1, the joining surfaces 1 a and 2 a are welded and joined by a laser arc hybrid welding apparatus 10.

The laser arc hybrid welding apparatus 10 includes a laser welding apparatus 20 and an arc welding apparatus 30. The laser arc hybrid welding apparatus 10 moves the laser irradiation head 21 of the laser welding apparatus 20 and the arc torch 31 of the arc welding apparatus 30 in the welding direction indicated by the arrows in FIG. Continuously welded in the longitudinal direction. At this time, arc welding is performed immediately after laser welding, and weld beads are sequentially formed in a form in which the laser melting portion 23 by laser welding and the arc melting portion 32 by arc welding are mixed. Laser welding may be performed immediately after arc welding.

  The laser welding apparatus 20 is substantially the same as a known configuration, and laser light produced by a laser transmitter (not shown) is sent to the laser irradiation head 21. The laser irradiation head 21 linearly irradiates the laser light 22 condensed by the internal condenser lens toward the joint surfaces 1a and 2a. Thus, the laser beam 22 generated by laser welding enters the welding depth direction (vertical direction in FIG. 1) with respect to the joint surfaces 1a and 2a. Further, the laser irradiation head 21 ejects a shielding gas in the same direction as the laser beam 22. Laser welding by the laser welding apparatus 20 is, for example, YAG welding, fiber laser, CO2 laser, or the like.

  The arc welding device 30 has the same configuration as that of a known one, and an arc torch 31 is disposed above the joint surfaces 1a and 2a, and a welding wire (not shown) is directed from the tip of the arc torch 31 toward the joint surfaces 1a and 2a. Sending out. A power source (not shown) supplies a predetermined power between the arc torch 31 and the upper surfaces of the steel members 1 and 2 to generate an arc. As a result, the arc generated by arc welding enters the welding surfaces 1a and 2a in the welding depth direction. The arc welding by the arc welding apparatus 30 is, for example, MIG welding, MAG welding, or the like.

  Here, as shown in FIG. 1, the steel members 1 and 2, which are objects to be joined, are thick plate-like members having a plate thickness exceeding 10 mm, and are long and having a longitudinal dimension exceeding 10 m. It is a large structure. Flat joining surfaces 1a and 2a are formed at the ends of the opposing steel members 1 and 2, respectively. Since these joining surfaces 1a and 2a are pressed against each other in the width direction when they are welded, they come into continuous contact with each other in the longitudinal direction at a specified position defined in the width direction.

  However, since the steel members 1 and 2 are large structures and are long, bending due to manufacturing errors and their own weight occurs. For this reason, according to the position of the steel members 1 and 2 in the longitudinal direction, the positions of the joining surfaces 1a and 2a are shifted from the specified position in the width direction, or a large gap 3 is generated between the joining surfaces 1a and 2a. . In particular, the gap 3 may be larger than the width of the laser beam 22. In order to eliminate this gap, there is a method of processing the joint surfaces 1a and 2a with high accuracy, but an extra process is added, and thus the cost increases.

  In the conventional laser arc hybrid welding method, as shown in FIG. 14A, when the joint surfaces 101a and 102a are displaced from the specified position P2, the laser beam 122 does not pass through the joint surfaces 101a and 102a. The laser melting portion 123a is formed only on one plate-like member 102. Thereby, as shown in FIG. 14B, the joining length h1 of the joining surfaces 101a and 102a is shortened. Further, as shown in FIG. 15A, if a gap 103 larger than the width of the laser beam 122 is generated between the bonding surfaces 101a and 102a, the laser beam 122 passes through the gap 103, and the laser melting portion. Is not formed. Accordingly, as shown in FIG. 15B, the joining length h2 of the joining surfaces 101a and 102a is shortened. As a result, depending on the position in the longitudinal direction, there is a problem that a part having a long joining length or a part having a short joining length is generated and the joining strength is not uniform.

  Therefore, in the laser arc hybrid welding method of the present embodiment, as shown in FIG. 1, the laser beam 22 is inclined and irradiated to the joint surfaces 1 a and 2 a in order to deal with the above-described problems. Yes. Specifically, as shown in FIG. 2, the laser beam 22 is emitted from a reference axis K1 extending in the welding depth direction (vertical direction in FIG. 2) of the joint surfaces 1a and 2a, and an orthogonal axis T1 of the joint surfaces 1a and 2a. It is inclined by an angle α. Note that the distance D shown in FIG. 2 is the distance between the position where the laser beam 22 is irradiated and the position where the arc is generated on the upper surfaces 1b, 2b of the steel members 1, 2 (the reference axis K1 and the laser beam 22 are The distance between the irradiated position and the reference axis Kx extending in the welding depth direction).

  Thereby, the laser beam 22 enters from the upper surface 2b of the steel member 2, passes through a part of the welding surfaces 1a and 2a in the welding depth direction, and travels toward the lower surface 1c of the steel member 1. Thereby, a narrow and linear laser melting part 23 is formed around the irradiated laser beam 22 in the steel members 1 and 2. As a result, even if the joining surfaces 1a and 2a are shifted in the width direction from the specified position or the gap 3 is large, the laser melting portion 23 is reliably formed in any part of the joining surfaces 1a and 2a in the welding depth direction. Will be formed. The maximum width of the laser melting portion 23 is about 2 to 3 mm.

  In order to tilt the laser beam 22 in this way, a mechanism for tilting the laser irradiation head 21 is provided. As another method for inclining the laser beam 22, an actuator for changing the angle of the reflection mirror built in the laser welding apparatus 20 may be provided, and can be changed as appropriate. Thus, it is not necessary to significantly change the conventional laser welding apparatus 20, and the increase in equipment cost can be suppressed.

  On the other hand, in arc welding, unlike laser welding, deep penetration cannot be performed. Therefore, as shown in FIG. 1, the side where the arc is generated in the welding depth direction of the joining surfaces 1 a and 2 a (upper portion in FIG. 1). Only), a substantially trapezoidal or substantially semicircular arc melting portion 32 is formed. That is, since the steel members 1 and 2 have a thick wall shape of about 10 mm or more, no arc melting portion is formed up to the lower end portions of the joint surfaces 1a and 2a. The width of the arc melting portion 32 is about 10 mm and is sufficiently wide. Therefore, even if the joining surfaces 1a and 2a are displaced in the width direction from the specified position or the gap 3 is very large, the arc melting portion 32 is reliably formed at the upper end portions of the joining surfaces 1a and 2a. . In this arc welding, the arc is stabilized by laser irradiation. That is, the laser beam 22 induces an arc, and the arc is restrained near the laser irradiation point, so that a stable heat source can be obtained. Thereby, a favorable weld bead can be obtained.

  Next, the state in which the joining surfaces 1a and 2a are welded and joined by the laser arc hybrid welding method of the present embodiment will be described by dividing the situation in the position in the longitudinal direction. That is, in the following FIGS. 3, 4, 5, and 6, the longitudinal positions of the joint surfaces 1 a and 2 a are different. First, in the situation shown in FIG. 3, the joining surfaces 1a and 2a are not shifted in the width direction from the specified position P1, and no gap 3 is formed between the joining surfaces 1a and 2a. In such an ideal situation, the welding conditions shown in FIG. 2 are set for laser welding. That is, in laser welding, as shown in FIG. 3 (A), the laser beam 22 is irradiated at an angle α with respect to the joining surfaces 1a and 2a, so the lower side of the joining surfaces 1a and 2a in the welding depth direction. The laser melting part 23a is formed on the substrate. On the other hand, in arc welding, as shown in FIG. 3 (B), an arc melting portion 32a is formed at the upper end portions of the joint surfaces 1a and 2a.

  At this time, the welding conditions are set so that the arc melting portion 32a and the laser melting portion 23a are separated from each other in the welding depth direction on the joint surfaces 1a and 2a. Specifically, the distance shown in FIG. 2 is such that the position of the laser melting portion 23a formed by the joining surfaces 1a and 2a is below the lower end of the arc melting portion 32a formed by the joining surfaces 1a and 2a. D and angle α are set. As a result, as shown in FIG. 3B, on the joint surfaces 1a and 2a, the arc melting portion 32a and the laser melting portion 23a are separated in the welding depth direction, and the weld bead 40a is separated and formed. The length welded and joined at the joining surfaces 1a and 2a is the total length of the joining length x1 by the laser melting part 23a and the joining length y1 by the arc melting part 32a.

  On the other hand, in the situation shown in FIG. 4, unlike the ideal situation shown in FIG. 3, there is a slight gap 3b between the joining surfaces 1a and 2a, and the joining surfaces 1a and 2a are spaced from the specified position P1. It is shifted to one side of the direction (left side in FIG. 4). In this situation, in laser welding, as shown in FIG. 4A, the laser beam 22 is irradiated at an angle α, so that a laser melting portion 23b is formed at the lower ends of the joining surfaces 1a and 2a. And in arc welding, as shown to FIG. 4 (B), the arc fusion | melting part 32b is formed in the upper end part of the joining surfaces 1a and 2a. Thereby, on the joining surfaces 1a and 2a, the arc melting part 32b and the laser melting part 23b are largely separated in the welding depth direction, and the weld bead 40b is separated and formed, and the welding surfaces 1a and 2a are welded together. This length is the total length of the joining length x2 by the laser melting part 23b and the joining length y2 by the arc melting part 32b.

  Further, in the situation shown in FIG. 5, unlike the ideal situation shown in FIG. 3, there is a slight gap 3c between the joining surfaces 1a and 2a, and the joining surfaces 1a and 2a have a width from the specified position P1. It is shifted to the other side of the direction (right side in FIG. 5). In this situation, in laser welding, as shown in FIG. 5A, the laser beam 22 is irradiated at an angle α, so that the laser melting is performed slightly downward from the center of the welding depth direction of the joining surfaces 1a and 2a. A portion 23c is formed. And in arc welding, as shown to FIG. 5 (B), the arc fusion | melting part 32c is formed in the upper end part of the joint surfaces 1a and 2a. As a result, on the joining surfaces 1a and 2a, the arc melting portion 32c and the laser melting portion 23c are slightly separated in the welding depth direction, and the weld bead 40c is separated and formed, and the welding surfaces 1a and 2a are welded. The joining length is the total length of the joining length x3 by the laser melting part 23c and the joining length y3 by the arc melting part 32c.

  As can be seen from the comparison between FIG. 3B, FIG. 4B, and FIG. 5B, the total length of the joining length x1 and the joining length y1 shown in FIG. The total length of the junction length x2 and the junction length y2 shown in FIG. 5B and the total length of the junction length x3 and the junction length y3 shown in FIG. Therefore, by tilting the laser beam 22 as in the present embodiment, even if the bonding surfaces 1a and 2a are shifted from the specified position P1 to one side or the other side in the width direction, the bonding strength of the bonding surfaces 1a and 2a is almost the same. Can be.

  Further, in the situation shown in FIG. 6, unlike the ideal situation shown in FIG. 3, the bonding surfaces 1a and 2a are not shifted in the width direction from the specified position P1, but the laser beam 22 is interposed between the bonding surfaces 1a and 2a. A gap 3d larger than the width is generated. In this situation, in laser welding, as shown in FIG. 6 (A), the laser beam 22 is irradiated at an angle α, so that a laser melting portion 23d is formed at the intermediate portion between the joining surfaces 1a and 2a. And in arc welding, as shown to FIG. 6 (B), the arc fusion | melting part 32d is formed in the upper end part of the joining surfaces 1a and 2a. Thereby, on the joining surfaces 1a and 2a, the arc melting portion 32d and the laser melting portion 23d are slightly separated in the welding depth direction, and the weld bead 40d is formed separately, and welding is performed at the joining surfaces 1a and 2a. The joining length is the total length of the joining length x4 by the laser melting part 23d and the joining length y4 by the arc melting part 32d.

  As can be seen from the comparison between FIG. 3B and FIG. 6B, the total length of the joining length x1 and the joining length y1 shown in FIG. The total length of the junction length x4 and the junction length y4 is substantially the same. Therefore, by tilting the laser beam 22 as in the present embodiment, even if a large gap 3d is formed, the bonding strength of the bonding surfaces 1a and 2a can be made substantially the same.

  Here, the angle α at which the laser beam 22 is tilted will be described with reference to FIG. As shown in FIG. 7A, when the angle α1 is relatively small, the joining length R1 formed by the laser melting portion 23 on the joining surfaces 1a and 2a becomes large. However, the margin S1 that can absorb misalignment and gaps in the width direction is reduced. On the other hand, as shown in FIG. 7B, when the angle α2 is relatively large, the joining length R2 formed by the laser melting portion 23 on the joining surfaces 1a and 2a becomes small. However, the margin S2 that can absorb the positional deviation and the gap in the width direction is increased.

  For this reason, the joint lengths R1 and R2 and the margins S1 and S2 are in a trade-off relationship with the angle α at which the laser light 22 is tilted. Accordingly, the angle α is optimally set according to the positional deviation in the width direction and the size of the gap in the joining surfaces 1a and 2a of the steel members 1 and 2 to be joined. That is, when the positional deviation and the gap in the width direction generated on the joint surfaces 1a and 2a are large, the angle α is set large to ensure a margin. On the other hand, when the positional deviation and the gap in the width direction generated on the bonding surfaces 1a and 2a are small, the bonding strength is ensured as much as possible by setting the angle α small. Thus, the present embodiment is characterized in that the bonding strength can be selected while arbitrarily setting the angle α and absorbing the displacement in the width direction and the gap generated on the bonding surfaces 1a and 2a.

The effect of 1st Embodiment is demonstrated.
According to the laser arc hybrid welding method of the first embodiment, as shown in FIG. 3 (A), the laser beam 22 is irradiated with an inclination so as to intersect the bonding surfaces 1a and 2a. For this reason, as shown in FIG. 4A, even if the joining surfaces 1a and 2a are shifted from the specified position P1 to one side in the width direction (left side in FIG. 4), the laser is applied to the lower ends of the joining surfaces 1a and 2a. A melting part 23b is formed. On the other hand, as shown in FIG. 5A, even if the joining surfaces 1a and 2a are displaced from the specified position P1 to the other side in the width direction (the right side in FIG. 5), laser melting is performed at the intermediate portion of the joining surfaces 1a and 2a. A portion 23c is formed. Further, as shown in FIG. 6A, even if a large gap 3d is generated between the bonding surfaces 1a and 2a, the laser melting portion 23d is formed below the intermediate portion of the bonding surfaces 1a and 2a. . In this way, even if the positional displacement of the joining surfaces 1a and 2a or the large gap 3d occurs, the position of the laser melting portion 23 only slightly moves up and down, and the joining length by the laser melting portion 23 on the joining surfaces 1a and 2a is almost It becomes constant.

  On the other hand, in arc welding, the arc melting part 32 is formed only in the upper end part of the welding depth direction among the joining surfaces 1a and 2a. At this time, since the width of the arc melting part 32 is about 10 mm and is wide, the joining length by the arc melting part 32 becomes substantially constant even if the joining surfaces 1a and 2a are displaced and a large gap 3d occurs. Thereby, the total length of the joining length by the laser melting part 23 and the joining length by the arc melting part 32 becomes substantially uniform along the longitudinal direction. As a result, when the joining surfaces 1a and 2a of the long steel members 1 and 2 are welded together, the joining strength can be made uniform along the longitudinal direction. That is, even if the bonding surfaces 1a and 2a are misaligned or have a large gap 3d, the bonding surfaces 1a and 2a can be misaligned or the large gap 3d can be absorbed. Therefore, it is a method that can ensure a large margin (acceptable range), and can be effectively used as a welding method for large structures.

  And in the laser arc hybrid welding method of this embodiment, since only the mechanism which inclines the laser beam 22 with respect to the conventional laser arc hybrid welding apparatus is provided, it is not necessary to change the conventional apparatus significantly. That is, it is not necessary to provide a high-accuracy copying apparatus equipped with a camera and various sensors in order to cope with the positional deviation of the joining surfaces 1a and 2a and the large gap 3d, and it can be carried out while suppressing increase in equipment cost. . Further, there is no need to add a mechanism for weaving the laser light without increasing the laser output. Therefore, the laser arc hybrid welding can be carried out while maintaining the advantages of low heat input, low distortion, and high speed welding.

  Here, the technical idea of this embodiment will be described. The present embodiment is characterized in that the objects to be joined are two long and thick steel members 1 and 2. The steel members 1 and 2 have a length in the longitudinal direction of about 10 m or more and a plate thickness of about 10 mm, and are not used in the automobile field, such as the construction machine field and the railway vehicle field. It is a large structure used in. When laser-arc hybrid welding is performed along the longitudinal direction of the joining surfaces 1a and 2a of the steel members 1 and 2 which are such large structures, ideally, as shown in FIG. , 102a is desirably formed in the entire weld depth direction. However, in practice, the joining lengths h1 and h2 may be shortened as shown in FIGS. 14B and 15B depending on the position in the longitudinal direction.

  Therefore, in the present embodiment, as shown in FIG. 4 to FIG. 6, the positional shift of the joining surfaces 1 a and 2 a is not intended to form a melted portion in the entire welding depth direction of the joining surfaces 1 a and 2 a. Even if a large gap 3d occurs, the laser melting part 23 is reliably formed in any part of the welding depth direction of the joint surfaces 1a and 2a by irradiating the laser beam 22 with an inclination. Thus, the technical idea of the present embodiment is not to increase the joining strength of the long and thick steel members 1 and 2 as much as possible in the entire longitudinal direction, but to the positional displacement and largeness of the joining surfaces 1a and 2a. It is to make the joint strength as uniform as possible along the longitudinal direction so that it can correspond to the gap 3d.

Second Embodiment
Next, a second embodiment will be described. In the second embodiment, the description will focus on the parts different from the first embodiment, and the description of the same parts will be omitted. In the second embodiment, the welding conditions are different from those of the first embodiment, and as shown in FIG. 8 (A), the joining surfaces 1a and 2a are not displaced in the width direction from the specified position P1, and the joining surfaces 1a and 2a, In an ideal situation where no gap is formed between 2a, an angle β for tilting the laser beam 22 is set. As shown in FIG. 8B, the angle β is set such that the laser melting portion 23e is formed above the intermediate portion in the welding depth direction of the joint surfaces 1a and 2a. That is, as a welding condition, the angle β is set so that the arc melting portion 32e and the laser melting portion 23e are integrated in the welding depth direction on the joint surfaces 1a and 2a.

  Here, the effect of the second embodiment will be described with reference to FIG. FIG. 9 shows a state in which the position X in the width direction of the joint surfaces 1a and 2a is shifted from the position J1 to the position J2. In the first embodiment described above, since the laser melting portion 23 and the arc melting portion 32 are separated in the welding depth direction (vertical direction in FIG. 9) on the joint surfaces 1a and 2a, the position X of the joint surfaces 1a and 2a The range is J1 ≦ X <J2. On the other hand, in the second embodiment, the case where the position X of the joining surfaces 1a and 2a is the position J2 is included. Compared to the first embodiment, the joining length by the laser melting portion 23 and the arc melting portion 32 depend. Although the total length with the joining length is shortened, the range of the position X of the joining surfaces 1a and 2a is J1 ≦ X ≦ J2. For this reason, compared with 1st Embodiment, the amount which the joint surfaces 1a and 2a shift | deviate to the width direction comes to be accept | permitted large, and a bigger margin can be ensured.

<Third Embodiment>
Next, a third embodiment will be described. In the third embodiment, laser arc hybrid welding is applied to the components of the Keriba used in the construction machine field. The kelly bar is suspended from an earth drill, for example, and rotates together with an excavating tool attached to the lower end to perform excavation. The kellyba has a structure that can be expanded and contracted by a multi-stage cylindrical member, and has an inner kelly bar, a second kelly bar, a third kelly bar, and an outer kelly bar in order from the inside. The outer kelly bar is configured such that rotational torque is transmitted from the drive shaft on the outer peripheral side, and each kelly bar can also transmit rotational torque.

  FIG. 10 is a cross-sectional view showing the relationship between the outer kelly bar 4 and the drive shaft 5. As shown in FIG. 10, the outer kelly bar 4 is a cylindrical member extending in the longitudinal direction (direction perpendicular to the paper surface of FIG. 10), has a length in the longitudinal direction of about 20 m, and a diameter of about 400 mm. It is a long large structure having a thickness of about 10 mm. The key members 6 are arranged on the outer peripheral surface 4a of the outer kelly bar 4 at intervals of 120 degrees in the circumferential direction. And the outer peripheral surface 4a of the outer kelly bar 4 and the side surface 6a of each key member 6 are continuously welded and joined in the longitudinal direction.

  Each key member 6 is fitted in each key groove 5 a formed on the inner peripheral side of the drive shaft 5. As a result, the outer kelly bar 4 receives the rotational torque from the drive shaft 5 via the key members 6. Each key member 6 is a bar member having a substantially rectangular cross section and extending in the longitudinal direction. The long side length of the rectangle is about 40 mm, and the short side length of the rectangle is about 20 mm. Here, FIG. 11 is an enlarged view of a portion Z in FIG.

  As shown in FIG. 11, the outer peripheral surface 4a of the outer kelly bar 4 and the side surface 6a of the key member 6 are opposed to each other along the longitudinal direction, and the upper left corner of the key member 6 in FIG. . In addition, although the corner part of FIG. 11 lower left of the key member 6 is also fillet welded, illustration is abbreviate | omitted in FIG. In this fillet welding, the same laser arc hybrid welding method as that in the first embodiment is used. That is, in laser welding, the laser beam 22 is irradiated with being inclined with respect to the outer peripheral surface 4 a of the outer kelly bar 4 and the side surface 6 a of the key member 6.

  Specifically, the laser beam 22 is approximately 20 from the reference axis K2 extending in the welding depth direction (vertical direction in FIG. 11) of the outer peripheral surface 4a and the side surface 6a toward the orthogonal axis T2 of the outer peripheral surface 4a and the side surface 6a. It is tilted by ~ 25 degrees. Thereby, the laser beam 22 enters from the upper surface 6b of the key member 6, and passes through a part of the outer peripheral surface 4a and the side surface 6a in the welding depth direction. As a result, a narrow and linear laser melting portion 24 is formed around the irradiated laser beam 22. On the other hand, in arc welding, the tip of the arc torch 31 (see FIG. 1) is arranged toward a slight gap 7 formed between the outer peripheral surface 4a and the side surface 6a. Thereby, the arc fusion | melting part 33 is formed only in the side (upper part of FIG. 11) where an arc generate | occur | produces in the welding depth direction among the outer peripheral surface 4a and the side surface 6a.

  Thus, also in the laser arc hybrid welding method of the third embodiment, the laser beam 22 is irradiated with an inclination so as to intersect the outer peripheral surface 4a and the side surface 6a. For this reason, even if a positional deviation or a large gap 7 occurs between the outer peripheral surface 4a and the side surface 6a, the position of the laser melting portion 24 only slightly moves up and down in the welding depth direction, and laser melting occurs at the outer peripheral surface 4a and the side surface 6a. The joining length by the part 24 becomes substantially constant. On the other hand, in arc welding, since the width of the arc melting portion 33 is about 10 mm and is wide, even if a positional deviation or a large gap 7 occurs between the outer peripheral surface 4a and the side surface 6a, the joining length by the arc melting portion 33 is almost equal. It becomes constant. Thereby, the total length of the joining length by the laser melting part 24 and the joining length by the arc melting part 33 becomes substantially uniform along the longitudinal direction. As a result, when the outer peripheral surface 4a and the side surface 6a are joined by welding, the joining strength can be made uniform along the longitudinal direction.

  In particular, in the third embodiment, the outer kelly bar 4 which is a large structure and a long cylindrical member is affected by manufacturing errors and deflections compared to the steel members 1 and 2 which are plate members of the first embodiment. Come out very big. For this reason, when the side surface 6a of the key member 6 is welded to the outer peripheral surface 4a of the outer kelly bar 4, misalignment of the outer peripheral surface 4a and the side surface 6a and a large gap 7 are likely to occur. Therefore, even under such severe conditions, the joining strength can be made uniform along the longitudinal direction by using the laser arc hybrid welding method of the present embodiment.

As mentioned above, although each embodiment of the laser arc hybrid welding method which concerns on this invention was described, this invention is not limited to these embodiment, A various change is possible in the range which does not deviate from the meaning.
For example, in the first embodiment, the laser beam 22 is incident from the upper surface 2b of the steel member 2 and inclined toward the lower surface 1c of the steel member 1, but is incident from the upper surface 1b of the steel member 1. The steel member 2 may be inclined toward the lower surface 2c.

Further, in the second embodiment, the angle at which the laser beam 22 is inclined is changed from the angle α of the first embodiment to the angle β in order to bring the arc melting portion 32e and the laser melting portion 23e into contact with each other at the joining surfaces 1a and 2a. However, the distance between the position where the laser beam 22 is irradiated and the position where the arc is generated may be changed from the distance D of the first embodiment, and both the angle α and the distance D may be changed.
Further, the laser arc hybrid welding method of the third embodiment is applied to the welding joint between the outer peripheral surface 4a of the outer kelly bar 4 and the side surface 6a of the key member 6, but is applied to the welding joint between other kelly bars and the key member. May be. Moreover, you may apply to welding joining with a long cylindrical member and a rod member with large structures other than Keriba.

  Further, in each embodiment, in arc welding, the arc torch 31 is arranged so as to extend in the welding depth direction of the joint surface, but the direction in which the arc torch 31 extends can be changed as appropriate. That is, the width of the arc melting portion to be formed is about 10 mm, while the positional deviation of the joint surface and the size of the gap are about 2 to 3 mm. Further, the laser beam 22 induces an arc, restrains the arc in the vicinity of the laser irradiation point, and the arc is stabilized. For this reason, in the laser arc hybrid welding of this embodiment, even if the direction in which the arc torch 31 extends is changed, there is almost no influence.

  In each embodiment, the position where the laser beam 22 is irradiated and the position where the arc is generated are separated by 0 to 3 mm in the longitudinal direction of the workpiece (steel members 1 and 2, outer kelly bar 4 and drive shaft 5), and laser We are doing arc hybrid welding. However, the distance (0 to 3 mm) separated in the longitudinal direction described above may be greater than 3 mm depending on the type of workpiece, welding conditions, and the like, and can be changed as appropriate.

DESCRIPTION OF SYMBOLS 1, 2 Steel member 1a, 2a Joint surface 3, 3b-3e, 7 Crevice 4 Outer kelly bar 4a Outer peripheral surface 6 Key member 6a Side surface 10 Laser arc hybrid welding apparatus 20 Laser welding apparatus 21 Laser irradiation head 22 Laser light 23, 23a- 23e, 24 Laser melting part 30 Arc welding device 31 Arc torch 32, 32a to 32e, 33 Arc melting part K1, K2, Kx Reference axis T1, T2 Orthogonal axis P1, P2 Specified position

Claims (4)

A laser arc hybrid welding method in which joining surfaces of two long workpieces which are large structures are opposed to each other, and the joining surfaces are continuously welded in the longitudinal direction of the joining surfaces by laser welding and arc welding. In
In the arc welding, only the portion where the arc is generated in the welding depth direction among the joining surfaces is joined by the arc melting part,
In the laser welding, a laser beam to be irradiated is tilted from a reference axis extending in the welding depth direction toward an orthogonal axis of the joining surface, and only a part of the joining surfaces in the welding depth direction is lasered. A laser arc hybrid welding method characterized by joining by a fusion zone. In the laser arc hybrid welding method according to claim 1,
The laser arc hybrid welding method, wherein the arc melting portion and the laser melting portion are separated from each other in the welding depth direction on the joint surface. In the laser arc hybrid welding method according to claim 1,
The laser arc hybrid welding method, wherein the arc melting portion and the laser melting portion are integrated on the joining surface. In the laser arc hybrid welding method according to any one of claims 1 to 3,
The laser arc hybrid welding method, wherein the two workpieces are a cylindrical member and a rod member welded to the outer peripheral surface of the cylindrical member.

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