JP2002336982A - Composite welding method for thin plate structural joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a widely applicable welding method with which sound welding can be performed by combining laser welding with arc welding, without causing fall-off in the welding of thin plate structural joints, even in the presence of a gap between members, and also in the case of deviation of joining faces from a desired position caused by assembling errors. SOLUTION: This is a method for welding joints in which members to be welded are composed of thin plates, by combining arc welding with laser welding. Welding conditions for the composite welding method for the thin plate structural joints are set to: laser output: 0.5-40 kW, arc current: 30-500 A, welding speed: 1-20 m/min, and arc/laser distance on the surface of joint members: 1-15 mm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of a method for welding a joint, and more particularly, to welding a butt joint, a lap joint or the like of a thin plate structure in which a member to be welded is formed of a thin plate. The present invention relates to a composite welding method for a thin-plate joint that performs welding by combining arc welding and laser welding.

[0002]

2. Description of the Related Art FIG. 3 is a front view showing a conventional butt joint using a steel plate as a member to be welded (base material to be welded). As shown in FIG. 3, the horizontal steel plates 1 and 2 are assembled in a state where they abut each other, and the front end surface 1 a of the steel plate 1 and the front end surface 2 a of the steel plate 2 are in contact with each other.

FIG. 4 is a front view showing a conventional lap joint. As shown in FIG. 4, the horizontal steel plates 3 and 4 are assembled vertically shifted, and the back surface 3b of the steel plate 3
And the surface 4c of the steel plate 4 is in contact.

In a butt joint and a lap joint having a thin plate structure assembled as shown in FIGS. 3 and 4, welding is usually performed by arc welding.

As a conventional welding method, a method of performing welding by laser welding is also conceivable.

[0006]

However, the thickness of the members to be welded constituting these joints is small, for example, 4 mm.
There are problems to be solved in the case of performing the above-described conventional method, that is, in the case of performing arc welding on a member as shown in FIGS.

That is, when welding members as shown in FIGS. 3 and 4, when arc welding is performed on a thin plate having a plate thickness of less than 4.0 mm, for example, a 3.5 mm thin steel plate as a member to be welded, In the normal arc welding condition range, the heat input per unit length becomes excessive, resulting in dropouts and making it impossible to perform sound welding.

[0008] As an effective means for preventing this,
A method of reducing the heat input by reducing the welding current and a method of reducing the heat input by increasing the welding speed are conceivable.

[0009] However, even in the case where dropout can be prevented by the above method, when the thin steel sheet is targeted, the heat input is still excessive, and the fatigue strength is reduced due to the formation of an excessive margin. Since the weld metal portion is too large, the amount of shrinkage after welding becomes large, causing problems such as excessive welding deformation.

If the welding current value is further reduced or the welding speed is increased to prevent these problems, the calculated heat input can be reduced. Welding cannot be performed.

In order to solve the above-mentioned problems, a method of welding by laser welding is also considered as a conventional method. According to this laser welding, excessive welding and welding deformation can be suppressed to an extremely small level. Have different problems described below.

That is, when assembling actual members, it is very difficult to precisely set the steel sheet to the state shown in FIGS. 3 and 4, and for example, the steel sheet shown in FIGS. A gap (G) often occurs between welding members.

When laser welding is performed on a butt joint and a lap joint having a gap between members as described above, the laser beam penetrates through the gap. In addition, even when welding can be performed without causing laser beam penetration, the molten metal for the volume of the gap formed by the gap is insufficient and a weld cannot be formed. Welding cannot be performed. In addition, since the sensitivity to the gap depends on the thickness of the member (ie, the thinner the thickness, the smaller the gap amount at which sound welding can be performed), when laser welding is performed on a thin steel plate, In this case, it is necessary to assemble the members so that the gap amount is 0 or a value very close to 0.

However, as described above, it is extremely difficult to assemble with extremely high precision such that there is no gap over the entire length of the welding line. To be sensitive
A laser welding method capable of performing sound welding even when a gap exists is desired.

Further, since it is difficult to accurately assemble the steel sheet, even if the gap can be suppressed to a small value, the position of the joining surface may deviate from a target position. In such a case, in laser welding having an extremely narrow melting width, welding surfaces may not be melted and welding defects may occur.

In addition, as the strength of the steel sheet increases, the workability deteriorates, so that it is difficult to secure the assembling accuracy (increase in the gap and the amount of displacement). Further, as the thickness of the steel sheet decreases, the sensitivity to the gap increases. For example, in the case where the thickness and strength of a steel sheet for an automobile have recently been advanced, it is more difficult to perform laser welding soundly.

As a means for solving the problem relating to the gap, a method of performing laser welding while supplying a welding wire (filler wire) is also considered as a conventional method.
According to this method, compared to the case of ordinary laser welding (without filler wire), the molten metal can be replenished, so that it is less likely to fall out, and the allowable gap amount is slightly increased. However, in the method using a filler wire, the wire feeding amount is limited, and the effect of increasing the allowable amount of the gap is small.

The present invention has been made in view of such a problem, and by combining arc welding with laser welding, it is possible to prevent falling off even when welding is performed on a joint having a thin plate structure. Sound welding can be obtained, and sound welding can be performed even when there is a gap between members. Sound welding can be performed even when the joint surface is displaced from a desired position due to an assembly error. It is an object of the present invention to provide a welding method having a wide applicable range.

[0019]

The inventors of the present invention have conducted intensive studies and experiments in order to achieve the above object.
The welding method described in claims 1 to 5 at the beginning of the specification of the present application is proposed here as an effective solution. That is, the composite welding method of the present invention according to claim 1 is a method of welding arc welding and laser welding to a joint in which members to be welded are made of thin plates and welding these thin plate structural joints. The welding conditions were as follows: laser output: 0.5 to 40 kW, arc current: 30
５００500 A, welding speed: 1-20 m / min, and arc / laser distance on the surface of the joint member: 1-15 mm.

Further, the composite welding method according to the present invention according to claim 2 is the composite welding method according to claim 1, wherein the thickness of the thin plate is less than 4.0 mm. The plate thickness is 3.5m
m or less, preferably 3.5 mm or less and 0.5 mm or more.

According to the third aspect of the present invention, the thin plate is a thin steel plate.
2. The composite welding method according to (1).

Further, the composite welding method according to the present invention according to claim 4 is the composite welding method according to any one of claims 1 to 3, wherein the joint formed of the thin plate is a butt joint or a lap joint. It is.

According to a fifth aspect of the present invention, there is provided a composite welding method according to any one of the first to fourth aspects, wherein the arc welding is a welding method using a consumable electrode. Is the way.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail focusing on its technical significance and operation.

The basic technical idea of the method of the present invention is to perform welding by combining arc welding when performing laser welding on a thin plate member. It can solve the disadvantages of the conventional method of performing welding, and can combine the advantages of both.

That is, when welding is performed on a joint made of a thin plate by an arc alone, the arc becomes unstable, so that the heat input cannot be reduced. Inconveniences such as the occurrence of overfilling, excessive fatigue, a decrease in fatigue strength, and an increase in welding deformation occur. These defects reduce the arc current or
Alternatively, it can be reduced by increasing the welding speed, but in practice, under such conditions, the arc becomes unstable and it becomes impossible to perform sound welding.

However, when welding is performed by combining laser welding with arc welding, the arc can be stabilized even at a low current or a high welding speed, and the above-described problem can be solved.

The mechanism by which the problem of arc welding is solved when performing composite welding is unknown, but the arc and laser beam or plasma interact with each other to increase the stability of the arc, and the above-mentioned problem is caused. I think it produces such an effect.

The problem with laser welding alone is that if the assembly position is displaced due to the difficulty of assembling the members or if there is a gap between the members, a sound welding is performed immediately. Is no longer possible. These problems become particularly significant when welding a thin plate member having a plate thickness of less than 4 mm, particularly a thin plate member having a plate thickness of 3.5 mm or less.

However, when welding is performed by combining laser welding with arc welding, the above-described problem can be solved.

That is, when performing welding while supplying a filler wire during laser welding, as described above, there is a slight effect of expanding the gap allowance. However, instead of supplying the filler wire, the wire is supplied by arc welding. If this is done, the effect will increase dramatically, and welding with a wide gap tolerance will be realized. The reason that the gap sensitivity can be somewhat reduced by the method using the filler wire is that the filler metal can replenish the molten metal filling the gap formed by the gap. However, the filler wire cannot be spontaneously melted, and is melted as a heat source by being inserted into a very narrow laser beam, so that it does not melt when the supply amount is excessive. Therefore, in the method using the filler wire, there is a limit to the replenishment amount of the molten metal, and accordingly, the effect of expanding the allowable range with respect to the gap is small.

However, when the molten metal is replenished by arc welding instead of the filler wire, the wire can be spontaneously melted by its own arc, so that a large amount of molten metal can be replenished. Therefore, the effect of expanding the allowable range with respect to the gap is dramatically increased as compared with the case of the filler wire.
This effect is effective in the case of combining laser welding with arc welding using non-consumable electrodes (TIG welding) in the sense that the heat source for melting the wire increases, but in order to obtain dramatic results It is more effective to combine arc welding using consumable electrodes.

As a problem in the case where the thin plate member is assembled and welded, not only a gap but also a positional deviation due to an assembly error can be considered. For example, although the members are originally assembled to form a butt joint as shown in FIG. 9 and the position indicated by the arrow is to be welded, the position actually set as shown in FIG. 10 ( FIG.
(Dotted line in FIG. 10) may be assembled (solid line in FIG. 10). However, even in such a case, the misalignment of the member settings could not be recognized, and the position of the originally planned arrow was welded, and in some cases, the butt surface was not melted at all or was melted only insufficiently. Instead, for example, it is conceivable that a welding defect as shown in FIG. 2 occurs. Since the width of the weld metal portion formed by laser welding, that is, the width to be melted, is very small, if the aim of the member setting is deviated, a problem occurs immediately.

In order to solve this problem, a method of changing the welding position of the laser welding each time in accordance with the setting deviation and welding the set position of the member can be considered. Such a method is not practical because it leads to a significant increase in the time involved in welding and increases the production cost. Therefore, it is required that sound welding can be performed at the same welding position even when the member settings are slightly shifted.

The above-mentioned problem relating to the misalignment of the members can be solved by the welding method according to the present invention in which laser welding is combined with arc welding.
That is, the reason that laser welding cannot cope with setting deviation is due to the extremely narrow width of the fusion zone as described above. However, according to the composite welding, in order to combine the arc welding having a large fusion zone with the laser welding due to the spread of the arc, compared with the case where the laser is used alone, the fusion zone having a wider fusion zone (the welding zone) is used. ) Can be obtained.

Therefore, even when the members at the setting positions as shown in FIG. 10 are welded, the joint surface can be melted by the composite welding, and a sound weld as shown in FIG. 1 can be obtained. Can be done.

Here, the narrow melting width in laser welding is disadvantageous with respect to setting deviation, but has an advantage in terms of welding distortion. That is, basically, the welding distortion tends to be smaller as the welding width is smaller. Therefore, the method of increasing the width of the fusion zone by combining arc welding with laser welding can solve the problem of setting deviation, but is considered to cause welding deformation similar to arc welding.

In practice, however, the width of the fusion zone can be made larger in the composite welding than in the case of the laser welding alone, but it does not become too large as in the case of the arc welding alone. Therefore, the problem of setting deviation can be solved without causing welding deformation as in the case of arc welding alone. Although the reason is unclear, the inventors believe that the explanation is as follows.

That is, the reason why the width of fusion can be increased as compared with the case of laser welding alone is that the spread of arc in arc welding is wider in composite welding than in laser welding. is there.

The reason why the welding width can be narrowed as compared with the case of arc welding alone and the welding deformation can be reduced is as follows.

That is, according to the welding method of the present invention in which arc welding is combined with laser welding, as described above, welding is performed at a welding speed as high as that of laser welding, where the arc becomes unstable in the case of arc welding alone. Can do
In addition, since ordinary arc welding alone can perform welding in a low current region where arcing becomes unstable, it becomes possible to reduce the amount of heat input by arc welding per unit welding length.

The penetration depth of the composite welding is
Since it can be earned by penetration by laser welding, under the same arc welding conditions, when performing arc alone welding and when combining arc welding and laser welding, composite welding has a deeper penetration depth You can do it.

Therefore, as for the arc welding conditions for obtaining the same penetration depth, the composite welding can suppress the heat input to a lower level, so that the melting width becomes narrower.

Furthermore, in the case of arc welding alone, the arc spreads, resulting in an excessive melting width.
In the case of composite welding, a phenomenon was observed in which the arc was concentrated by being pulled by the laser beam. In combination with such an arc concentration effect by the laser beam, it seems that the fusion width can be suppressed to an appropriate amount in the composite welding.

The reasons for limiting the numerical values of the welding conditions in the joint welding method according to the present invention will be described below.

Laser output (0.5 to 40 kW) It is not preferable that the laser output is less than 0.5 kW because the effect of the composite welding is reduced. On the other hand, when the thickness exceeds 40 kW, when the thin plate member is used as a member to be welded, particularly when welding is performed on a member having a plate thickness of less than 4 mm, dropout occurs, and it becomes impossible to perform sound welding. Not preferred. Therefore, in the present invention, the laser output is specified in the range of 0.5 to 40 kw.

Arc current (30 to 500 A) If the arc current is less than 30 A, the arc becomes unstable even in composite welding, which is not preferable. If it exceeds 500A, when the thin plate member is to be a member to be welded, particularly when welding is performed on a member having a plate thickness of less than 4 mm, dropout occurs, and it becomes impossible to perform sound welding. Not preferred. In addition, it is not preferable because the fatigue strength is reduced due to the formation of an excessive margin and the welding deformation is increased due to excessive heat input. Therefore, in the present invention, the arc current is specified in the range of 30 to 500A. About welding speed (1 to 20 m / min) When the welding speed is set to less than 1 m / min, similarly when a thin plate member is used as a member to be welded, particularly when a member having a plate thickness of less than 4 mm is welded. 1m / mi because it may fall off or cause welding deformation.
It is preferable to set n or more. In addition, 20m / min
Exceeding the range is not preferable because the arc becomes unstable even in the composite welding according to the present invention, and sound welding cannot be performed. Therefore, in the present invention, the welding speed is 1 to 20 m /
Specify in the range of min.

Laser / arc distance (1 to 15 mm) The laser / arc distance is the distance D on the surface of the member to be welded when the laser torch (left side) and the arc torch (right side) are set in FIG. As shown,
If the distance between the arc and the laser is less than 1 mm, the arc and the laser interfere more than necessary, and it is not preferable because sound welding cannot be performed. Further, when the distance exceeds 15 mm, the interaction between the arc and the laser is diluted or lost, and the sufficient effect of the present invention cannot be obtained, which is not preferable. Therefore, in the present invention, the laser / arc distance is specified in the range of 1 to 15 mm.

[0049]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a welding method according to the present invention, in which laser welding is combined with arc welding and welding is performed, will be referred to as an implementation method of the present invention (hereinafter simply referred to as an implementation method). The case where welding is performed alone is referred to as a comparison method, and the practical method and the comparison method are compared and specifically described.

First, in the welding method of the embodiment method and the comparison method, the allowable amount capable of performing sound welding when there is a gap was examined. FIG. 11 shows the butt joint used in this test.

In both the implementation method and the comparison method, a butt joint is assembled by using steel plates 5 and 6 having a plate thickness of 3.5 mm as shown here, and the assembling is performed between the end surfaces 5a and 6a of the steel plates 5 and 6 at the time of assembly. , That is, the value of the gap (G) was variously changed, and welding was performed.

As for the welding method, arc welding was performed by MAG welding using Ar + 20% CO2 as sealed gas, and a wire having a diameter of 1.2 mmφ was used. A CO2 laser was used for laser welding. The composite welding was made by combining them.

Table 1 shows detailed welding conditions for the implementation method and the comparison method. These welding conditions are such that the gap (G) is 0 in the butt joint having a thickness of 3.5 mm shown in FIG.
When the gap was changed, the conditions under which complete penetration welding could be realized were selected, and the same conditions were applied to the joint when the gap amount was changed. The reason for conducting the test under the same conditions without changing the welding conditions depending on the gap amount is that even when the members are actually assembled by automatic welding, the gap amount is measured and fed back, and the welding conditions corresponding to the gap amount are measured. I do n’t make any changes,
Gap = 0 when the setting is as desired
In order to perform welding under appropriate welding conditions for the state of mm, this is simulated.

[0054]

[Table 1]

Table 2 shows the test results. Here, ○ and × in the judgments in Table 2 indicate that, with regard to dropouts, those that could be welded without falling off, and those that failed to perform healthy welding due to dropouts. ×, with regard to deformation, 変 形 indicates that deformation could not be confirmed at the visual level or was extremely slight, × indicates that welding deformation was apparent, and 総 合 indicates both omission and deformation as comprehensive evaluation. (Passed) when it became ×, × (failed) when both or one of them became ×
And

[0056]

[Table 2]

As shown in Table 2, in the composite welding of the practical method, the gap amount of Nos. 1 to 5 was 0 mm to 1.5 m.
Under all conditions up to m, sound welding could be performed without any dropout, and the amount of deformation after welding was small, so the overall judgment was "good" (pass).

On the other hand, in the case of the laser welding alone of the comparative method, when the gap amount of No. 1 to No. 3 was 0.5 mm or less, it dropped out and the deformation was ○, and the overall judgment was ○. When the gaps of Nos. 4 and 5 had a gap of 1.0 mm or more, dropouts occurred, so that sound welding could not be performed. Therefore, Nos. 4 and 5 were also judged as x (fail) in the comprehensive evaluation. In addition, in the case of the arc welding alone of the comparative method, the allowable range for the gap is generally considered to be wider than that of the laser welding. However, in this test result, the gap of the same level as in the case of the laser welding alone is one. Omission occurred in a range of 0.0 mm or more.
This is because the conditions selected in this test are such that complete penetration welding can be achieved for a state where the gap is 0 mm. It was thought that when it was present, it was easy for dropout to occur. Regarding the welding deformation, the deformation amount was determined to be large under all the conditions, and therefore, all the conditions were also determined to be × in the comprehensive evaluation. From these results, the following findings were obtained. In other words, although the laser welding alone of the comparative method is excellent in terms of welding deformation, the allowable amount when a gap is present is small and a dropout occurs. Did not. On the other hand, in the case of the arc welding alone of the other comparative method, the dropout is almost the same as that of the laser welding alone, and the welding deformation is large regardless of the gap amount, so it was rejected under all conditions. Was. In contrast, in the case of the composite welding according to the present invention, excellent results were obtained for both the allowable gap and the welding deformation. Welding could be performed. Therefore, compared to the case of laser welding alone or arc welding alone of the comparative method, the welding range that can achieve sound welding that does not cause omission and has a small deformation amount is the range of the composite welding according to the method of the present invention. Is better. Next, as another embodiment, an evaluation test for assembling errors was performed in an implementation method in which laser welding was combined with arc welding and a comparison method in which welding was performed using only arc welding and laser welding alone. Appropriate welding conditions were selected. FIG. 12 shows the butt joint used for the test. In both the implementation method and the comparison method, in the butt joint assembled by the 3.5 mm thick steel plates 7 and 8 as shown here, the respective end faces 7a of the steel plates 7 and 8 are used.
And the distance between 8a and 8a, that is, the value of the gap is set to 0 (in FIG. 12, the gap is provided for easy understanding, but the actual gap is 0), and the end faces 7a and 8a are set.
A position at a fixed distance (amount of shift in the figure) away from the contact surface of a was welded, and the evaluation when the setting was shifted and the welding conditions were evaluated. The evaluation method used was the same as in the above-mentioned gap-related test in terms of the occurrence of dropout during welding and the magnitude of deformation after welding.However, in this test, in addition to these, the contact surface was As an index to measure whether a complete weld was formed by melting completely, a base material fractured by performing a tensile test after welding was evaluated as ○ (pass), and a fracture at the weld was evaluated as × (failed) ). As a final evaluation method, those in which all of the above-mentioned determinations regarding the omission, deformation, and deviation allowable amount were passed were evaluated as comprehensive, and the overall evaluation was made. The welding method is CO2 for arc welding.
With CO2 welding used as sealed cap, diameter 1.2m
An mφ wire was used. A YAG laser was used for laser welding. The composite welding was made by combining them. Table 3 shows detailed welding conditions and test results of Examples and Comparative Examples.

[0059]

[Table 3]

Nos. 1 to 9 shown here are based on the implementation method of the present invention, that is, Examples, and as proposed by the present invention,
Since the composite welding conditions were within an appropriate range, the overall evaluation passed in all conditions. The displacement was acceptable even at the maximum value of 2 mm performed in this test. Nos. 10 to 16 were obtained by composite welding, but were rejected in the comprehensive evaluation because the welding conditions were out of the proper range defined by the present invention. That is, No.
In No. 10, since the laser output was smaller than the claimed range, the effect of the composite welding could not be obtained, the arc became unstable, and a sound welding could not be performed. As a result, the member contact surface could not be completely melted, and was rejected in the tensile test. In addition, since the arc current of No. 11 was smaller than the claimed range, the arc became unstable, and it was not possible to perform sound welding.
As a result, the member contact surface could not be completely melted, and was rejected in the tensile test. In No. 12, since the arc current was larger than the claimed range, dropout occurred, and it was not possible to perform sound welding. No.13
Since the welding speed was lower than the claimed range, not only was it not possible to obtain the advantage in terms of efficiency due to the realization of high-speed welding with composite welding, but also welding deformation occurred. The results of the tensile test also failed. In No. 14, since the welding speed was higher than the claimed range, the arc became unstable, and sound welding could not be performed, and the tensile test was rejected. In No. 15, since the laser / arc distance was smaller than the claimed range, the laser and the arc interfered more than necessary, the arc and the laser beam became unstable, and the tensile test was rejected. In No. 16, since the laser / arc distance was larger than the claimed range, the effect of the composite welding could not be sufficiently obtained, the arc became unstable, and the tensile test failed. In addition, No. 17-21
Is a comparative example using laser welding alone, and the allowable range was investigated by changing the amount of deviation. As a result, the composite evaluation was acceptable in the comprehensive evaluation up to the entire range (maximum value 2 mm) of the deviation amount performed this time, but the laser welding alone was 0.5 m
m or below, the contact surface could not be completely melted in a range beyond that, resulting in a failure. Further, Nos. 22 to 26 are comparative examples using only arc welding, and the same tests as those using only laser welding were performed. As a result, welding deformation occurred in all the implemented condition ranges, and therefore, all were rejected even in the comprehensive evaluation. By the way, when evaluating only the permissible range for the amount of deviation, excellent results were obtained compared to laser welding.
It passed up to 1.5 mm, but failed 2 mm, which was passed by composite welding. In the above-described embodiment, a steel plate is used as the thin plate member. However, the welding method of the present invention is not limited to the steel plate, and may be applied to other metal plates (or alloy plates thereof) as long as the material can be welded. Needless to say, it can be implemented in the same manner.

[0061]

As described in detail above, according to the method of the present invention, laser welding can be combined with arc welding, and the welding conditions can be selected and performed by appropriately combining the welding conditions in such combined welding. Even when the member is welded to a joint member made of a thin plate, a sound weld can be obtained without dropout and sound welding can be performed even when there is a gap between the members. Can,
Further, even when the joint surface is deviated from a desired position due to an assembly error, excellent welding having a wide applicable range such as sound welding can be realized.

[Brief description of the drawings]

FIG. 1 is a front view showing the state of a welded portion when a butt joint having a setting deviation is welded by the composite welding method of the present invention.

FIG. 2 is a front view showing a state of a welded portion when a butt joint having a setting deviation is welded by a conventional welding method.

FIG. 3 is a front view showing a conventional butt joint.

FIG. 4 is a front view showing a conventional lap joint.

FIG. 5 is a front view showing a gap generated between members constituting a conventional butt joint.

FIG. 6 is a front view showing a gap generated between members constituting a conventional butt joint and a vertical displacement.

FIG. 7 is a front view showing a gap generated between members constituting a conventional lap joint.

FIG. 8 is a front view showing an arc / laser distance in the composite welding method of the present invention.

FIG. 9 is a front view showing a relationship between a welding position expected for the butt joint and a position of a joining surface.

FIG. 10 is a front view showing a relationship between a welding position expected for a butt joint and a position of a joining surface actually set.

FIG. 11 is a front view showing a butt joint used in a comparative test between an implementation method according to the composite welding method of the present invention and a comparison method according to a conventional method.

FIG. 12 is a front view showing a butt joint used in another comparative test of an implementation method in the composite welding method of the present invention and a comparison method according to a conventional method.

[Explanation of symbols]

1-8: steel plate, G: gap, D: distance between arc and laser

Claims (5)

[Claims] 1. A method of combining arc welding and laser welding for a joint in which a member to be welded is made of a thin plate and welding the same, wherein the welding conditions are set to a laser output of 0.5. -40 kW, arc current: 30-500 A,
A composite welding method for a thin-plate joint, wherein the welding is performed at a welding speed of 1 to 20 m / min and an arc / laser distance on the joint member surface of 1 to 15 mm. 2. The method according to claim 1, wherein the thickness of the thin plate is less than 4 mm. 3. The composite welding method according to claim 1, wherein the thin plate is a steel plate. 4. The composite welding method according to claim 1, wherein the joint made of the thin plate is a butt joint or a lap joint. 5. The composite welding method according to claim 1, wherein the arc welding is a welding method using a consumable electrode.