JP2014205166A - Laser welding method and laser arc hybrid welding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser welding method and a laser arc hybrid welding method, capable of preventing degradation in welding quality caused by irradiation of laser to a backing material.SOLUTION: A laser welding method is performed in a state in which a butt joint portion is supported by a backing material when plate-like metal members 1, 2 are jointed together by the butt joint. Laser light is irradiated by lateral weaving so as to cross a junction part where joint end surfaces 11, 12 of the metal members 1, 2 are abutted with each other. A laterally swung portion is taken as a heating portion 21 for raising laser output, and a portion across the junction part is taken as a non-heating portion 22 for zeroizing or lowering laser output.

Description

  The present invention relates to a laser welding method and a laser-arc hybrid welding method that are performed in a state in which a joining portion that abuts a pair of members to be joined is supported by a backing material, and in particular, the backing material is irradiated with laser light. The present invention relates to a laser welding method and a laser-arc hybrid welding method that prevent deterioration of the welding quality caused by.

  When, for example, a pair of steel plates are butt-joined as the members to be joined, laser light is irradiated to a joint portion where the joining end surfaces of the steel plates are butt-joined, and the respective base materials are melted and joined. At this time, a thick steel plate needs to be melted up to the back surface of the joint, so that the amount of heat input by the laser light increases. At that time, a backing material is disposed on the opposite side to which the laser beam is irradiated so that the base material of the molten joint portion does not melt away.

JP-A-5-131283 JP 2003-170284 A

“Lazerx Q & A, Part 5: Laser welding”, [online], [Search on March 15, 2013], Internet <URL: http://www.laserx.co.jp/technology/qa/part5.html>

  By the way, when the members to be joined are long and the joining distance is long, even if the joints of the joining end faces are processed with high precision, a tolerance gap will be generated when the joining end faces are brought into contact with each other. A place arises. In laser welding of butt joints, the laser beam is usually irradiated aiming at the position (joint part) of the abutting surfaces of the members to be joined. The material is irradiated with laser light. Then, the backing material melts and evaporates / decomposes, and the weld quality is deteriorated, for example, a blow hole is generated in the joint portion of the member to be joined. In view of this, a laser welding method that avoids the passage of gaps by such laser light is disclosed in Patent Document 1. Specifically, the laser beam irradiation position on the member to be bonded is shifted by 0 to 0.8 mm from the abutting surface, and the irradiation direction is not parallel to the abutting surface but is inclined by 3 to 9 degrees to irradiate the laser beam. This is a laser welding method.

  The present invention provides a laser welding method and a laser-arc hybrid welding method that prevent deterioration in welding quality that may be caused by laser irradiation of a backing material in order to solve the problem by a method different from the conventional example. With the goal.

The laser welding method according to the present invention is performed in a state in which the butt joint portion is supported by a backing material when the plate-shaped metal members are joined together by a butt joint, and the laser beam is emitted from the metal Irradiated while weaving left and right so as to cross the joint where the joint end faces of the members are butted together, the laser output is raised with the part that swings left and right as the heated part, and the laser output with the part that crosses the joint as the non-heated part It is characterized by being zero or lowered.
Moreover, in the laser welding method according to the present invention, it is preferable that the locus of the laser beam irradiated while weaving is made into a waveform.
In the laser welding method according to the present invention, it is preferable that the locus of the laser beam irradiated while weaving is made into a waveform that is further weaved by a heated portion that is swung left and right.

The laser-arc hybrid welding method according to the present invention is performed in a state where the plate-like metal members are joined together by a butt joint, with the butt joint part being supported by a backing material, and laser light is emitted in advance. Irradiated and arc welding is performed behind it, and the laser beam is irradiated while weaving left and right so as to cross the joint where the joint end surfaces of the metal members are abutted to each other, and heats the part that sways left and right The laser output is increased as a part, and the laser output is reduced to zero or reduced by using a part crossing the joint as a non-heated part, and arc welding is performed on a linear joint where the joint end faces of the metal member are butted together. It is characterized by performing.
Further, in the laser-arc hybrid welding method according to the present invention, the locus of the laser beam irradiated while weaving is made into a waveform, or a waveform further made to be further weaved by a heated portion that sways left and right. preferable.

  According to the present invention, even if a gap exists in the joint portion where the joining end faces of the plate-like metal members are abutted with each other, the laser light only crosses the gap in order to make the irradiation position of the laser light weave. . In addition, the laser output is raised with the portion that has swung left and right as the heating portion, while the laser output is reduced to zero or lowered with the portion that crosses the joint as the non-heating portion. Therefore, even if the laser beam is irradiated to the backing material through the gap, the backing material does not melt and does not cause blowholes or the like in the joint, and can prevent deterioration in welding quality. it can.

It is the perspective view which showed the butt joint of steel plates, and has shown the gap part in which the clearance gap produced especially. It is a top view of the joined part showing the laser welding method of a 1st embodiment, and shows the locus of the laser beam irradiated especially continuously. It is the top view of the junction which showed the laser welding method of 2nd Embodiment, and has shown the locus | trajectory of the laser beam irradiated especially continuously. It is the top view of the junction which showed the laser arc hybrid welding method of 3rd Embodiment. It is the top view of the junction part which showed the other implementation plan of the laser arc hybrid welding method. The graph shows the relationship between the amount of heat input per hour by laser light and the penetration depth.

  Next, embodiments of a laser welding method and a laser / arc hybrid welding method according to the present invention will be described below with reference to the drawings. Embodiment shown below joins the butt joint formed between plate-shaped steel members, and is a welding method especially for the thick plate-shaped member or plate-shaped part which requires a backing material. is there. FIG. 1 is a perspective view showing a butt joint between steel plates, and particularly shows a portion (gap portion 8) where a gap is generated.

  The steel plates 1 and 2 are plate materials having a thickness exceeding 10 mm, for example, and straight and flat joining end surfaces 11 and 12 are formed as butt joints at respective end portions. In joining, since the joining end surfaces 11 and 12 of such steel plates 1 and 2 are pressed, the junction part which the joining end surfaces 11 and 12 contact will continue in a welding direction. However, when the joining part of the steel plates 1 and 2 is long, a gap as shown in the figure is formed between the joining end faces 11 and 12 due to tolerance. The laser welding method and laser-arc hybrid welding method of the present embodiment consider such a gap portion 8 and prevent the backing material 3 from being melted by the laser light that has passed through the gap.

  FIG. 2 is a plan view of the joint portion showing the laser welding method of the first embodiment, and particularly shows a locus 20 irradiated with continuously irradiated laser light. For the laser welding apparatus that irradiates the laser beam so as to have such a locus 20, for example, an apparatus as described in Patent Document 2 is used. That is, it is a laser welding apparatus that performs welding while weaving laser light. In such a laser welding apparatus, welding laser light produced by a laser oscillator (not shown) is sent to the laser head, and the laser light collected by the condensing lens therein is irradiated onto the joint.

  In particular, since the laser beam trajectory 20 has a waveform that swings to the left and right with respect to the welding direction X, the laser welding apparatus includes a weaving mechanism. The weaving mechanism has, for example, an actuator that changes the angle of the reflecting mirror, and thereby swings the reflecting mirror so that the irradiation direction of the laser beam is swung left and right within a predetermined angle range. As a result, the laser beam locus 20 draws a preset waveform. Further, the laser welding apparatus can set the control of the laser beam output and the moving speed of the laser head with respect to the welding traveling direction X, in addition to the setting of the optical path in which the locus 20 is drawn.

  Therefore, in the first embodiment, on the locus 20 of the laser beam having a waveform, output control of the laser beam is performed using a curved line portion indicated by a thick solid line and a straight line portion indicated by a broken line. The curved portion is a portion where the laser beams can be irradiated to the steel plates 1 and 2 without fail, so that the heating portion 21 having a high laser output is used. On the other hand, since the straight portion crosses the gap portion 8, the non-heated portion 22 is set so that the laser output is zero or low. By doing so, the base material of the joint portion is melted and joined, and even if the laser beam passes through the gap portion 8, the backing material 3 is not melted, and the conventional welding quality is improved. Prevent decline.

  The heating portions 21 are alternately positioned on the left and right sides across the joining portion (gap portion 8), and are discontinuous in each of the steel plates 1 and 2 when viewed along the welding progress direction X. Therefore, in order to ensure the welding quality, it is necessary to adjust the heat input so that the steel plates 1 and 2 are melted at an appropriate depth and range in each heating portion 21. Therefore, in the laser welding apparatus, control settings such as the output of laser light and the moving speed of the laser head are performed. Here, FIG. 6 is disclosed in Non-Patent Document 1 and shows the relationship between the amount of heat input per time by the laser beam and the penetration depth. The horizontal axis represents the welding speed, and the vertical axis represents the penetration depth.

  The results shown in FIG. 6 are obtained by using a fiber laser and a YAG laser. The fiber laser has an output of 7 kW, 10 kW, and 17 kW, and the YAG laser has an output of 4 kW. The LD excitation type and the lamp excitation type are used. It has been done. And in each laser output, the penetration depth with respect to the steel plate which changed the welding speed was measured, and the result as shown in a graph is obtained. Although not specifically shown, it is possible to measure not only the penetration depth but also the welding range by checking the weld cross section.

  In the laser welding apparatus, control settings such as the laser output and the welding speed are performed in consideration of the penetration depth and the welding range associated therewith based on such measurement values. Further, in the laser welding apparatus, in addition to the laser output and the welding speed, control setting of the amplitude, wavelength and frequency of the locus 20 of the laser beam, which is a waveform, and the switching timing of the heating part 21 and the non-heating part 22 is performed. .

  Therefore, in the laser welding apparatus (not shown) in which such control settings are performed, the laser head moves linearly along the welding progress direction X. At this time, the reflecting mirror is swung, so that the laser beam is irradiated so as to draw a set waveform, and the locus 20 as shown in FIG. 2 is traced. Further, the output of the laser beam is controlled by the heating part 21 and the non-heating part 22.

  For example, the welding speed is 0.3 to 1.0 m / min, and the frequency of the waveform of the locus 20 is 10 to 30 Hz. Since the output of the laser light is lowered at the timing of the non-heated portion 22, the laser oscillator controls the ON / OFF of the laser output at 20 to 60 Hz, which is a frequency that is almost twice the locus 20 of the laser light. However, if the output is reduced to zero with a laser oscillator, stable output control becomes difficult. For example, when the maximum output is 10 kW, the minimum output is reduced to about 10% of 1 kW. / OFF control. If stable output control is possible, it is desirable to set the laser output at the non-heated portion 22 to zero.

  Thereby, even if the gap part 8 exists in the junction part of the steel plates 1 and 2, the heating by a laser beam is performed so that the gap may be straddled. Even if the laser beam is irradiated to the backing material 3 through the gap, the output is weak and only crosses. Therefore, it is possible to prevent the welding quality from being deteriorated, for example, the laser beam melts the backing material 3 and causes a blow hole at the joint between the steel plates 1 and 2. On the other hand, in the steel plates 1 and 2, the joint portions of the joining end surfaces 11 and 12 are melted and joined to each other by the laser light applied to the heating portion 21.

  Next, FIG. 3 is a plan view of the joint portion showing the laser welding method of the second embodiment, and in particular, shows a locus 30 of laser light irradiated continuously. Also in this embodiment, the above-described laser welding apparatus is used, and weaving is performed by moving the laser beam irradiation position to the left and right by controlling the laser output and the welding speed or by the weaving mechanism. The laser beam trajectory 30 determined by the weaving includes a heating portion 31 and a non-heating portion 32 as shown in the figure.

  In particular, in the case of the trajectory 30, there is even smaller weaving when it swings to one of the steel plates 1 and 2, and a small waveform is formed in the heated portion 31. Therefore, in the trajectory 30, when compared with the trajectory 20 shown in FIG. 2, the distance of the heating portion 31 is increased and the amount of heat input at one location is increased, while the non-heated portion 32 crossing the joint (gap portion 8). And the number of times the backing material 3 is irradiated is reduced.

  Therefore, according to the present embodiment, similarly to the first embodiment, the heating portion 31 is heated by laser irradiation so as to straddle the gap between the steel plates 1 and 2. Further, in the gap portion 8, even if the laser beam is irradiated on the backing material 3 through the gap, the laser output is controlled to be zero or low and only crosses. In particular, in laser light irradiation such as the locus 30, the number of times of crossing the gap portion 8 is small. Therefore, it is possible to more effectively prevent the deterioration of the welding quality, for example, the laser beam melts the backing material 3 and causes a blow hole at the joint between the steel plates 1 and 2.

  On the other hand, in the steel plates 1 and 2, the joint portions of the joining end surfaces 11 and 12 are melted and joined to each other by the laser light applied to the heating portion 31. Moreover, in this embodiment, even if the capability is low regarding a laser welding apparatus, since irradiation time becomes long by the heating part 31, a base material can be fuse | melted appropriately and welding quality can be ensured.

  By the way, although the case of laser welding was demonstrated in the said embodiment, you may make it laser-arc hybrid welding which performs arc welding (MIG welding or MAG welding) other than irradiation of a laser beam besides this. FIG. 4 is a plan view of the joint showing the laser-arc hybrid welding method of the third embodiment. In the laser-arc hybrid welding method of the third embodiment, when viewed along the welding progress direction X, a laser head is disposed in front and a welding wire is disposed behind the laser head.

  Then, laser irradiation with weaving as shown in the first or second embodiment is performed from the preceding laser head. That is, the laser beams are applied to the steel plates 1 and 2 so that the trajectories 20 and 30 shown in FIGS. Again, the heated portions 21 and 31 increase the laser output while the non-heated portions 22 and 32 cause the laser output to be zero or low. Subsequently, arc welding 40 is performed behind the welding progress direction X irradiated with the laser beam. The arc welding 40 is performed on the joint where the joint end faces 11 and 12 are abutted against each other. For example, shield gas is supplied and MIG welding using a welding wire is performed.

  In the present embodiment, the joint portions of the joining end surfaces 11 and 12 are joined to the steel plates 1 and 2 by such a two-stage process. That is, the joining portion of the steel plates 1 and 2 is heated by the preceding laser light irradiation, and the steel plates 1 and 2 are joined together by the arc welding 40 that follows. In the present embodiment, it is preferable to chamfer the corners of the joining end surfaces 11 and 12 so that a groove can be formed in the joining portion.

  In such laser / arc hybrid welding, two heat sources having different energy densities are used. Therefore, the welding speed can be increased as compared with mere arc welding, and the penetration depth can be easily adjusted as compared with laser welding alone, and the welding finish on the back surface of the joint can be improved. Similarly to the first and second embodiments, even if the laser beam is irradiated to the backing material 3 through the gap of the gap portion 8 (see FIGS. 2 and 3), the output is zero, or Since it is low and only crosses, the laser beam melts the backing material 3, and it is possible to prevent a deterioration in welding quality such as causing a blow hole at the joint between the steel plates 1 and 2.

  Subsequently, another implementation plan in the laser-arc hybrid welding method will be described. FIG. 5 is a plan view of a joint showing another implementation of the laser / arc hybrid welding method. In the third embodiment, the laser beam is weaved, but the laser beam may be irradiated linearly so that a locus 45 shown in the drawing is obtained. However, if the joint portion is irradiated with the laser beam, the backing material 3 is melted through the gap of the gap portion 8, so that the laser beam is moved in parallel with the joint portion so as to become the locus 45, and the steel plate Only one of 1 and 2 is irradiated. Similarly to the third embodiment, the arc welding 40 is performed on the joint portion where the joint end faces 11 and 12 are abutted against each other. The arc welding 40 is supplied with a shielding gas, for example, and MIG welding with a welding wire is performed. In addition, if a twin beam is possible with a laser welding apparatus, you may make it irradiate both the steel plates 1 and 2 with a laser beam.

  Also in this implementation plan, since two heat sources having different energy densities are used, the welding speed can be increased as compared with arc welding, and the penetration depth can be adjusted as compared with laser welding. It becomes easy and the welding finish of the back surface of a junction part can be improved. Further, in this embodiment, since the laser beam does not pass through the gap portion 8 at all, the backing material 3 is not irradiated with the laser beam. Therefore, the laser beam does not melt the backing material 3, and it is possible to effectively prevent a deterioration in welding quality such as causing a blow hole at the joint between the steel plates 1 and 2.

The embodiments of the laser welding method and the laser / arc hybrid welding method according to the present invention have been described above. However, the present invention is not limited to this, and various modifications can be made without departing from the spirit of the present invention.
For example, in the second embodiment, the heating portion 31 has a waveform, but when it is swung to one of the steel plates 1 and 2, the heating portion 31 is straight without any small weaving so that the heating portion has a trapezoidal shape. Also good. The same applies to the laser-arc hybrid welding of the third embodiment.

1, 2 Steel plate 3 Backing material 8 Gap portion 11, 12 Joint end face 20 Trajectory 21 Heated portion 22 Non-heated portion

Claims (5)

In the case of joining plate-like metal members by a butt joint, in the laser welding method performed in a state where the butt joint part is supported by a backing material,
The laser beam is irradiated while weaving left and right so as to cross the joint where the joint end surfaces of the metal members are abutted, and the laser power is increased by using the part that sways left and right as the heating part, and the part crossing the joint is not A laser welding method characterized in that the laser output is reduced to zero or reduced as a heated portion. The laser welding method according to claim 1, wherein
A laser welding method, wherein a locus of the laser beam irradiated while weaving is formed into a waveform. The laser welding method according to claim 1, wherein
The laser beam welding method is characterized in that the locus of the laser beam irradiated while weaving is formed into a waveform further reduced by a heated portion swayed from side to side and further weaved. When plate-like metal members are joined together by a butt joint, the laser is performed in a state where the butt joint part is supported by a backing material, irradiated with laser light in advance, and arc welded behind it.・ In the arc hybrid welding method,
The laser beam is irradiated while weaving left and right so as to cross the joint where the joint end surfaces of the metal members are abutted, and the laser power is increased by using the part that sways left and right as the heating part, and the part crossing the joint is not Try to reduce the laser power to zero or lower as a heating part,
A laser-arc hybrid welding method characterized in that arc welding is performed on a linear joint obtained by abutting joint end faces of the metal member. In the laser-arc hybrid welding method according to claim 4,
The laser-arc hybrid welding method characterized in that the locus of the laser beam irradiated while weaving is formed into a waveform, or a waveform further reduced in a heated portion that has been swung left and right and further subjected to a weaving.

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