JP2008114233A - Weld joint for laser welding, and welded body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a weld joint for laser welding for performing the welding of excellent quality while suppressing generation of blow holes. <P>SOLUTION: The weld joints 10A, 10B are formed on first and second members 1A, 1B to be welded by the laser welding or the laser arc hybrid welding while spraying a shield gas. The first member 1A to be welded has a welding projection 11 to be butted to a welding end face of the second member 1B to be welded, and a supporting projection 6 for receiving second members 13, 14 to be welded which are butted to the welding projection 11 on the counter-application side of laser beams. The supporting projection 6 forms a recess 12 recessed on the application side of laser beams. An inner surface of the recess 12 is continuous from a surface part 22 on the counter-application side formed on the welding projection 11 to a bottom side 24 of the recess. The bottom side 24 of the recess extends over a welding end face 21 of the welding projection 11, projected to the application side, and continuous to a fore end supporting part 25 for receiving the second members 13, 14. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a welded joint for laser welding for laser welding or laser-arc hybrid welding of a member to be joined made of, for example, aluminum or an aluminum alloy material, and in particular, a joined body having improved joint quality by eliminating defects such as blow holes. The present invention relates to a joint for laser welding for constituting a joint and a joined body laser welded by the joint.

  In railway vehicles and the like, a vehicle structure made of a light aluminum alloy material is adopted to cope with the weight reduction of the vehicle body. For joining aluminum alloy members, MIG welding or the like that uses a welding wire as a consumable electrode is employed. For example, as shown in FIG. 9, the outer plates 101 and 102 constituting the railway vehicle structure have joints formed at their ends, and the end surfaces are inclined so as to form a groove at the joint 110. Superimposed. More specifically, a receiving portion 105 is formed on one outer plate 101, and an end portion of the other outer plate 102 is overlapped therewith to form a groove having a V-shaped cross section as shown. . Since MIG welding is performed in an inert gas, the shielding gas is injected, and the outer plates 101 and 102 are welded while melting the welding wire in the joint 110 having the groove.

  On the other hand, recently, laser welding has been attempted in addition to arc welding for joining aluminum alloy members. The laser beam has the property of a concentrated heat source with high energy density, can be welded by deep penetration with low heat input, has very little thermal influence and deformation on the parts to be joined, and can be welded at high speed. It is. However, the laser welding method for aluminum alloy members has a problem in that defects such as blow holes occur and the back surface is oxidized frequently occur. In this regard, Japanese Patent Application Laid-Open No. 7-164173 proposes a laser welding method for stably providing a joined body having a high-quality welded part when laser welding aluminum alloy members to each other.

FIG. 10 is a cross-sectional view of the joint disclosed in the publication. The plate members 201 and 202 made of an aluminum alloy have convex portions 211 and 212 having rectangular cross sections at the end portions, and a cavity 220 is formed by abutting the end surfaces with each other. A laser beam is irradiated onto the joint portion 230 of the plate members 201 and 202 from above in the drawing, and welding is performed along a joint line where the joint portion 230 is continuous. At that time, a shield gas is injected toward the joint 230 from the same direction as the laser beam, and on the opposite side, the back shield gas is supplied from the other opening end with one opening end closed in the cavity 220. The Therefore, in the joint joint shown in FIG. 10, since inert gas is supplied as the back shield gas and laser welding is performed, defects such as blowholes can be extremely reduced, and high quality welding is performed. There is an effect that a joined body having a portion can be stably obtained.
JP 7-164173 A (page 3-4, FIG. 1)

  However, in the joint joint of Patent Document 1 shown in FIG. 10, it is necessary to provide the convex portions 211 and 212 on the plate members 201 and 202 in order to form the cavity 220 for supplying the back shield gas. Patent Document 1 describes joint joints that similarly form cavities other than those shown in FIG. 10, but both have shapes for forming cavities, such as convex portions 211 and 212. Such an extra portion greatly increases the weight of a joined body such as a railway vehicle structure. Moreover, in such a conventional joint joint, since the back shield gas is supplied into the cavity 220 in addition to the shield gas injected from the same direction as the laser beam, extra time is required for joining, and the joining apparatus can also be used. It will be expensive.

  Therefore, in order to solve this problem, an object of the present invention is to provide a joint for laser welding and a joined body welded by the joint for performing high-quality welding with suppressed generation of blowholes. .

  The joint for laser welding according to the present invention is joined by laser welding or laser-arc hybrid welding performed while spraying a shielding gas to a joint where the joining end surfaces of the first and second members to be joined are abutted. Therefore, the first and second members to be joined include a joining protrusion that abuts against a joining end surface of the second joining member, and a laser non-irradiation side. And a support projection for receiving the second member to be joined, which is abutted against the joint projection, and the support projection is formed with a recess recessed on the laser irradiation side, and the inner surface of the recess is The flat surface on the anti-irradiation side formed on the bonding protrusion is continuous from the bottom surface of the recess, the bottom surface of the recess extends beyond the bonding end surface of the bonding protrusion, and protrudes toward the irradiation side to form the second member to be bonded. receive Characterized in that it is one that is formed so as to be continuous to the end support.

In the joint for laser welding according to the present invention, the support protrusion has a substantially semicircular curved surface from the flat surface of the joint protrusion, the concave bottom surface substantially parallel to the laser irradiation side member surface, and a substantially semicircular shape. It is preferable that the tip support portion is formed so that the curved surface is continuous.
In the laser-welded joint according to the present invention, it is preferable that the joint protrusion of the first member to be joined has the same thickness as the joint portion of the second member to be joined.
In the laser welded joint according to the present invention, the first member to be joined and the second member to be joined are hollow members in which an upper surface plate and a lower surface plate are connected by a plurality of ribs, The member is formed by connecting the support protrusions formed on the upper surface plate side and the lower surface plate side by end ribs, and the upper and lower support protrusions are located between the upper surface plate and the lower surface plate of the second bonded member. It is preferable that the joining projections of the first member to be joined and the free ends of the upper surface plate and the lower surface plate of the second member to be joined are joined to each other.
In the laser welded joint according to the present invention, it is preferable that a groove is formed at a joint portion between end faces of the first member to be joined and the second member to be welded, and the groove portion is welded. .

The joined body of the present invention is obtained by joining a joint portion formed by combining the joints formed on the first and second members to be joined by laser welding or laser / arc hybrid welding performed while spraying a shielding gas. The joint joint includes a joint protrusion that is abutted against the joint end surface of the second joint member on the first member to be joined, and a joint that is abutted against the joint protrusion on the laser non-irradiation side. A support projection for receiving the second member to be joined, the support projection forming a recess recessed on the laser irradiation side, and an inner surface of the recess formed on the bonding projection on the non-irradiation side Is formed so as to extend from the flat surface portion to the bottom surface of the recess, the bottom surface of the recess extends beyond the bonding end surface of the bonding protrusion, and protrudes toward the irradiation side to be continuous with the tip support portion that receives the second member to be bonded. And characterized in that.
The joined body of the present invention is a hollow member in which the first and second members to be joined are connected to each other by a plurality of ribs. The first and second members to be joined are: The support protrusions formed on the upper surface plate side and the lower surface plate side are connected by end ribs, and the upper and lower support protrusions are fitted between the upper surface plate and the lower surface plate of the second joined member. It is preferable that the joining protrusions of the first member to be joined having the same thickness and the joining portions of the upper surface plate and the lower surface plate of the second member to be joined are brought into contact with each other and welded.

  Therefore, according to the present invention, the space formed by the concave portions of the support protrusions is sufficiently wide as the space for filling the shield gas, so that the bonding quality can be improved as compared with the conventional one. In addition, a flat portion is formed on the bonding projection, and by making the thickness of the other bonding portion to be welded the same, the diffusion of heat entered by the laser beam at the bonding portion becomes almost equal to the left and right, By melting the joined portion with a good balance between left and right, the joining time can be shortened and the joining quality can be improved.

  Next, an embodiment of a laser-welded joint according to the present invention and a joined body will be described below with reference to the drawings. First, FIG. 1 is a view showing a railway vehicle structure constructed by laser welding. This railway vehicle 80 forms a floor structure, a side structure 81 that forms left and right surfaces, a roof structure 82 that forms a roof, a wife structure 83 that forms surfaces that close both ends with respect to the longitudinal direction of the vehicle body. And a frame 84. In the side structure 81 and the roof structure 82, a plurality of extruded hollow members 88 having a length corresponding to one of the vehicle bodies are welded and joined in the width direction.

  Here, FIG. 2 and FIG. 3 are diagrams showing a laser welded joint of extruded hollow shapes which are members to be joined. This is a process leading to the laser welded joint shown in FIG. 4 and FIG. This shows a joint for laser welding. Therefore, after briefly explaining the laser welding joint joint of FIGS. 2 and 3, the laser welding joint joint of this embodiment will be described in detail. The extruded hollow shapes shown in the figure are all made of extruded aluminum alloy and correspond to the extruded hollow shapes 88 constituting the railway vehicle 80.

  First, the joint for laser welding shown in FIG. 2 is formed on the left end and the right end of the extruded hollow members 41A and 41B, respectively. In the extruded hollow member 41, the upper surface plate 42 and the lower surface plate 43 are connected by a plurality of inclined ribs 44. The end ribs 45 and 46 positioned at the left and right end portions are orthogonal to the upper surface plate 42 and the lower surface plate 43, a support protrusion 47 projects from the left end, and the upper surface plate 42 and the lower surface plate 43 extend at the right end. Protruding portions 42a and 43a protruding in this manner are formed. An arc-shaped groove 49 is formed in the longitudinal direction at the base of the support protrusion 47 on the laser irradiation surface side.

  Therefore, in the joint for laser welding of the extruded hollow members 41A and 41B, the support protrusions 47 and 47 are fitted between the protrusions 42a and 43a as shown in the figure. Therefore, the laser beam is irradiated to the bonding portion 48 where the bonding end faces are abutted with each other, and at the same time, the shielding gas is injected from the irradiation side. In the joint 48 irradiated with the laser beam, welding is performed by melting by intensive heating. At this time, there is a gap between the end faces in the irradiated portion of the laser beam, and the shield gas enters from the gap. Therefore, the shield gas injected from the laser irradiation surface side to the joint portion is filled in the space of the groove portion 49 and becomes the back shield gas.

  However, in the joint for laser welding shown in FIG. 2, the weight is increased because both end ribs 45 and 46 are provided. Further, since the groove portion 49 for storing the back shield gas is shallow and the cross-sectional area is small, there is not enough space for the shield gas to enter, and good quality may not be obtained. In addition, since the shape of the position irradiated with the laser beam is asymmetrical, the heat diffused by the laser beam is unevenly diffused, and in this respect as well, the bonding quality may be deteriorated.

  Then, as a joint shape for laser welding, the thing as shown in FIG. 3 can be considered next. In the extruded hollow members 51A and 51B shown in FIG. 3, the upper surface plate 52 and the lower surface plate 53 are connected by a plurality of inclined ribs 54, and an end rib 55 is formed only at the left end. The support protrusion 56 protrudes from the end rib 55, and free ends 57 and 58 are formed on the extension of the upper surface plate 52 and the lower surface plate 53 in the extruded hollow member 51B. A groove 59 is formed on the laser irradiation surface at the base of the support protrusion 56. The groove 59 is formed so as to be gently curved inward from the joint end surface 52a of the upper surface plate 52 and the joint end surface 53a of the lower surface plate 53, and the cross section of the space formed by overlapping the free ends 57 and 58 is a so-called water droplet. It has a shape.

  A laser beam is radiated to the bonded portion where the bonded end surfaces are abutted with each other, and a shielding gas is simultaneously injected. The joint irradiated with the laser beam is melted by intensive heating and welding is performed. At this time, there is a gap between the end faces in the irradiated portion of the laser beam, and the shield gas enters from the gap. Therefore, also in this laser welding joint, the shield gas injected from the laser irradiation surface side to the joint is filled in the space of the groove 59 to become the back shield gas.

However, the groove 59 in the joint for laser welding is deeper than the groove 49 in FIG. 2 and the space into which the shield gas enters is widened. However, there is a possibility that good quality cannot be obtained because it is not sufficient. is there. In addition, since the shape of the position irradiated with the laser beam is asymmetrical, the heat diffused by the laser beam is biased, so that there is a possibility that the bonding quality may be deteriorated.
In view of the above problems, the present inventors have proposed a joint for laser welding shown in FIGS. FIG. 4 is a view showing the ends of a pair of spaced extruded hollow members, and FIG. 5 is a view showing a joined state in which the ends are combined.

  A pair of extruded hollow members 1A and 1B shown in FIG. 4 are extruded hollow members of aluminum alloy, and a laser welding joint joint is formed in which the right end and the left end can be joined by laser welding. ing. The extruded hollow members 1A and 1B correspond to the extruded hollow members 88 constituting the railway vehicle 80 shown in FIG. 1, and a joint as shown in the figure is formed at the end in the width direction. In the extruded hollow shape members 1A and 1B, a substantially parallel upper surface plate 2 and lower surface plate 3 are connected by a plurality of ribs 4 inclined in the width direction to form a truss-shaped cross section.

  The joint for laser welding according to the present embodiment is a joint 10A formed at the left end of the extruded hollow member 1A, and the other joint of the laser welded joint is formed at the right end of the extruded hollow member 1B. It consists of a joint 10B. In the joint 10A, end ribs 5 orthogonal to the upper surface plate 2 and the lower surface plate 3 are formed, and support protrusions 6 project from the end ribs 5 at two upper and lower portions outward in the width direction. . The joint 10B has free ends 13 and 14 in which the upper surface plate 2 and the lower surface plate 3 extend from the rib 4 located at the right end of the extruded hollow member 1B. Since the end faces of the free ends 13 and 14 are aligned, the free end 13 on the top plate 2 side is long and the free end 14 on the bottom plate 3 side is short due to the inclination of the rib 4.

The support protrusions 6 and 6 of the joint 10A are configured to be fitted between the free ends 13 and 14 of the joint 10B, and the support protrusions 6 and 6 are formed in a vertically symmetrical shape. Therefore, the shape of the joint 10A on the lower surface plate 3 side will be described in more detail with reference to FIG.
The support protrusion 6 is formed at a connection portion between the lower surface plate 3 and the end rib 5. On the extended line of the lower surface plate 3, a joining projection 11 having a thickness larger than that of the lower surface plate 3 is formed, and the support projection 6 is formed so as to further protrude in the same direction as the joining projection 11. A tip support portion 25 bent to the front surface side is provided at the tip, and the tip support portion 25 is a portion that supports the free ends 13 and 14 of the joint 10B that is abutted against the joining projection 11 from the side opposite to the laser beam irradiation surface. become.

  And this support protrusion 6 forms the recessed part 12 for forming the space which stores shield gas at the time of laser joining. The recess 12 has a shape that allows the support protrusion 6 and the bonding protrusion 11 to be clearly recognized as separate protrusions, and continues from the bonding end surface 21 through the flat surface portion 22 to the arc portion 23 at the back, and forms a bag shape. It has become. A wide concave bottom surface 24 is formed in the concave portion 12, and a tip support portion 25 protrudes on the opposite side. Therefore, in the present embodiment, a wide space can be obtained by devising the shape of the support protrusion 6 instead of using a simple groove as in the previously proposed joint. Further, in the joint 10 </ b> A, the connection portion between the lower surface plate 3 (the same applies to the upper surface plate 2) and the end rib 5 is formed with a convex surface 15 with the opposite side of the support protrusion 6 facing inward, and the concave portion 12 spreads to The thickness of the wall is not reduced.

  On the other hand, the joint 10B is formed thick so that the tip portion 13a of the free end 13 on the upper surface plate 2 side and the entire free end 14 on the lower surface plate 3 side have the same thickness as the joint protrusion 11 of the joint 10A. Has been. Accordingly, since the bonding protrusion 11 is a protrusion having the flat surface portion 22 as described above, when the upper and lower bonding end faces 21 and 26 and 21 and 27 are in contact with each other as shown in FIG. The wall thickness is equally symmetrical with respect to the abutted surface (laser beam irradiation position).

  The extruded hollow profiles 1A and 1B of the present embodiment are double skin panels that are extrusion molded with the top plate 2 and the bottom plate 3 having a thickness of about 2 mm and the ribs 4 and 5 having a thickness of about 1.5 mm. Fig. 2 is a side panel of the railway vehicle shown in Fig. 1. Therefore, the joints 10A and 10B shown in FIGS. 4 and 5 are formed over a length of 20 and several meters. Then, when looking at the joint 10A, the flat portion 22 of the joining projection 11 constituting the concave portion 12 is formed with a length of 3.0 mm or less, and the interval between the concave portion bottom surface 24 and the flat portion 22 is 0.5 to 0.5 mm. It is formed with 3.0 mm. This is because when the concave portion 12 is shallow and the circular arc portion 23 is deep, the portion of the molding die becomes thin and the strength cannot be ensured, and it is difficult to produce a stable shape. Therefore, by molding with such dimensions, the strength of the molding die is ensured and the profile is stably manufactured.

  Therefore, when the extruded hollow members 1A and 1B are joined by laser welding using the joint for laser welding according to this embodiment, the support protrusions 6 and 6 are placed between the free ends 13 and 14 as shown in FIGS. Fit it with a fit. At this time, the joint end faces 21 and 26, 21 and 27 of the joint protrusion 11 and the free ends 13 and 14 having the same thickness are brought into contact with each other, and the tip support portion 25 of the support protrusion 6 connects the free ends 13 and 14 to the inside of the profile. Support from. Since the cross-sectional shape of the tip support part 25 is a substantially semicircular shape, the tip support part 25 is supported in a state in which the tip support part 25 is in line contact with the joining direction (the direction through the drawing). Therefore, it is easy to obtain dimensional accuracy as compared with surface contact, and each of the joining end surfaces 21 and 26 and 21 and 27 can be accurately matched.

  Next, a laser beam is irradiated to the joint from the outside of the upper surface plate 2 and the lower surface plate 3 to each joint where the joint end surfaces 21 and 26 and 21 and 27 are abutted, and the laser beam moves along the joint line. To do. From the same direction as the laser beam, shield gas is simultaneously injected toward the joint. For this reason, the joint irradiated with the laser beam is melted by intensive heating and welding is performed. At that time, the shield gas enters from the gap formed in the laser beam irradiated portion and fills the space of the recess 12. Then, an atmosphere of shield gas is generated on the back side of the laser beam irradiation surface.

Therefore, by performing laser welding in a state where the back shield gas is made, it is possible to suppress the generation of blowholes and realize high quality welding. Therefore, it was possible to improve the quality of the joint and improve the weld quality of the joined body formed by laser welding of the extruded hollow members 1A and 1B, for example, the railway vehicle structure shown in FIG.
In addition, by forming the support protrusions 6 constituting the recesses 12, it is possible to provide a joined body with a simple structure and improved joining quality. And since it is only necessary to inject the shielding gas in the same direction as the laser beam irradiation direction in the case of laser welding in the same manner as in ordinary laser welding, it is necessary to separately supply the back shielding gas as in Patent Document 1 shown in the conventional example. In this respect as well, it has become possible to easily obtain a joined body with improved joint quality.

And especially in this embodiment, since the space comprised by the recessed part 12 of the support protrusion 6 becomes large enough as a space filled with shield gas, it was able to make the joining quality better than the conventional one. .
Further, since the joining protrusion 11 is formed with a flat surface portion 22 and the joining protrusion 11 and the distal end portion 13a and the distal end portion 14 of the free end 13 have the same thickness, diffusion of heat entered by the laser beam at the joining portion is prevented. Almost right and left. Therefore, the melting time of the joining portion is performed with a good balance between left and right, so that the joining time can be shortened and the joining quality can be improved.

  Here, FIG. 7 is a view showing a modified example of the joint 10A, and is an enlarged view particularly on the lower surface plate side. In the embodiment, as shown in FIG. 6, the bottom surface 24 of the recess is substantially parallel to the surface of the flat portion 22 of the bonding protrusion 11 and the lower surface plate 3 (the same applies to the upper surface plate 2). However, it may be inclined like a recess bottom surface 24a shown in FIG. 7 (a), or may be an arc like a recess bottom surface 24b shown in FIG. 7 (b). By forming the shape of the concave bottom surfaces 24a and 24b in this way, the thickness of the support protrusion 6 can be increased and the strength can be increased.

Next, FIG. 8 is a view showing a joint for laser welding according to the second embodiment. In this embodiment, particularly, a case of joining by laser / arc hybrid welding in which laser welding and MIG welding are combined is shown. is there. The same components as those in the first embodiment will be described with the same reference numerals.
As in the first embodiment, the extruded hollow profiles 1C and 1D, which are the joined bodies, have a substantially parallel upper surface plate 2 and lower surface plate 3 connected by a plurality of ribs 4. The joint at the left end is formed with a support projection 6 that forms a joint projection 16 and a recess 12 from the end rib 5 toward the outside in the width direction, and is fitted into the free ends 17 and 18 of the right end joint. ing. Furthermore, in this embodiment, the joining projection 16 and the joining end surfaces of the free ends 17 and 18 are formed obliquely, and a groove 19 is formed when they are fitted as shown.

  Therefore, in the joining of the extruded hollow shapes 1C and 1D by laser / arc hybrid welding, the laser beam is irradiated to the groove 28 between the joining projection 16 and the free ends 17 and 18, and at that time, from the front in the traveling direction, Shield gas is supplied. And welding is performed by supplying a MIG arc with a MIG torch, for example in the back of the direction of travel. The shield gas supplied to the joint enters and fills the space of the recess 12 formed by the support protrusion 6, and an atmosphere of shield gas is generated.

Therefore, even in this embodiment, by creating an atmosphere of shielding gas on the back side of the joint, it is possible to suppress the generation of blowholes and realize high-quality welding, and improve the quality of the joint for joints such as railway vehicle structures. We can now offer what we have secured.
Further, by forming the support protrusion 6 having the concave portion, it is possible to provide a joined body with a simple structure and improved quality of the joint portion, and since it does not supply back shield gas separately, it is easy to handle. is there.

Also in this embodiment, since the space of the joint for storing the shielding gas is widened by the concave portion 12 of the support protrusion 6, better quality can be obtained compared to the conventional one.
Further, since the joining protrusion 16 has a shape in which the flat portion 22 (see FIG. 6) is formed, the joining protrusion 16 and the free ends 17 and 18 have the same thickness and are symmetric. . Therefore, the melting time of the joining portion is performed with a good balance between left and right, so that the joining time can be shortened and the joining quality can be improved.

As mentioned above, although one embodiment of the joint for laser welding and the joined body concerning the present invention was described, the present invention is not limited to this but can be variously changed within the range which does not deviate from the meaning.
For example, in the above-described embodiment, the extruded hollow member has been described as an example. However, the member to be joined is a flat plate, and the joint for laser welding according to the present invention is also applied to the case where the end is abutted and laser welded. can do. Further, the joined body is not limited to a railway vehicle structure.

It is the figure which showed the rail vehicle comprised by laser welding. It is the figure which showed one proposal of the joining joint for laser welding of the extrusion hollow shape material which is a to-be-joined member. It is the figure which showed one proposal of the joining joint for laser welding of the extrusion hollow shape material which is a to-be-joined member. It is one Embodiment of the joint joint for laser welding, Comprising: It is the figure which showed the edge parts of a pair of spaced-apart extruded hollow shape material. It is 1st Embodiment of the joint joint for laser welding, Comprising: It is the figure which showed the joining state which combined the edge parts of a pair of extrusion hollow shape materials. It is the figure which showed the joint shape of the 1st to-be-joined member. It is the figure which showed the modification of the joint shape of a 1st to-be-joined member. It is 2nd Embodiment of the joint joint for laser welding, Comprising: It is the figure which showed the joining state which combined the edge parts of a pair of extrusion hollow shape materials. It is the figure which showed the junction part of the outer plate | board of the railway vehicle structure joined by MIG welding. It is sectional drawing which showed the junction part which performs the conventional joining method of enclosing back shield gas and carrying out laser welding.

Explanation of symbols

1A, 1B Extruded hollow profile 2 Upper surface plate 3 Lower surface plate 4 Rib 5 End rib 6 Support projection 10A, 10B Joint 11 Joint projection 13, 14 Free end 21 Joint end surface 22 Planar portion 23 Arc portion 24 Recess bottom surface 25 Tip support portion

Claims (7)

The first and second objects to be joined by laser welding or laser-arc hybrid welding performed while spraying a shielding gas to the joined portion where the joining end faces of the first and second members are abutted. In the joint for laser welding formed on the joining member,
The first member to be bonded includes a bonding protrusion that is abutted against a bonding end surface of the second bonding member, and a support protrusion that is on the laser non-irradiation side and that receives the second member to be abutted against the bonding protrusion. Formed,
The supporting projection is formed with a concave portion recessed on the laser irradiation side, and the inner surface of the concave portion is continuous from the flat portion on the anti-irradiation side formed on the bonding projection to the bottom surface of the concave portion, and the bottom surface of the concave portion. Is formed so as to extend beyond the joining end face of the joining projection, to protrude toward the irradiation side, and to be continuous with the tip support portion that receives the second joined member. . In the laser-welded joint according to claim 1,
The support protrusion has a substantially semicircular curved surface from the flat portion of the joining protrusion, the bottom surface of the recess substantially parallel to the laser irradiation member surface, and the curved surface of the substantially semicircular tip support portion. A laser welded joint characterized by being formed. In the joint for laser welding according to claim 1 or claim 2,
A joining joint for laser welding, wherein a joining projection of the first joined member has the same thickness as a joining portion of the second joined member. In the joint for laser welding according to any one of claims 1 to 3,
The first member to be joined and the second member to be joined are hollow members in which an upper surface plate and a lower surface plate are connected by a plurality of ribs,
In the first member to be joined, the support protrusions formed on the upper surface plate side and the lower surface plate side are connected by end ribs, and the upper and lower support protrusions are connected to the upper surface plate of the second member to be bonded. It is fitted between the bottom plate and the joining projections of the first member to be joined and the upper end plate of the second member to be joined and the free ends of the bottom plate are brought into contact with each other. Joint for laser welding. In the joint for laser welding according to any one of claims 1 to 4,
A laser-welded joint joint, wherein a groove is formed at a joint between end faces of the first and second members to be welded, and the groove is welded. In the joined body formed by joining the joint part formed by combining the joints formed on the first member to be joined and the second member to be joined by laser welding or laser / arc hybrid welding performed while spraying the shielding gas,
The joint joint includes: a joint projection that is abutted with a joint end surface of the second joint member on the first member to be joined; and a second joint member that is abutted with the joint projection on a laser non-irradiation side. The support protrusion is formed with a recess recessed on the laser irradiation side, and the inner surface of the recess is recessed from the flat surface on the side opposite to the irradiation formed on the bonding protrusion. The bottom surface of the recess extends beyond the joining end surface of the joining projection, and protrudes toward the irradiation side to be continuous with the tip support portion that receives the second joined member. Characteristic joined body. The joined body according to claim 6,
The first member to be joined and the second member to be joined are hollow members in which an upper surface plate and a lower surface plate are connected by a plurality of ribs,
In the first member to be joined, the support protrusions formed on the upper surface plate side and the lower surface plate side are connected by end ribs, and the upper and lower support protrusions are connected to the upper surface plate of the second member to be bonded. The joining projections of the first joined members that are fitted between the lower surface plates and have the same thickness and the joined portions of the upper surface plate and the lower surface plate of the second joined members are butted against each other and welded. Characteristic joined body.

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