JP3596326B2 - Welding method of aluminum alloy - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an aluminum alloy welding technique using a high energy beam such as a laser beam or an electron beam. More specifically, the present invention increases the processing energy when welding an aluminum plate, extruded material, or aluminum casting. Further, the present invention relates to an aluminum alloy welding method capable of stably maintaining the welding process and obtaining a weld bead having a deep penetration amount.
[0002]
[Prior art and problems]
For example, when an aluminum alloy is used as a structural member of an automobile, a high energy beam such as a laser beam or an electron beam is applied as a welding energy source when manufacturing or assembling these members, compared with MIG welding or TIG welding. It is possible to perform welding at high speed, and it can be expected that the welding time can be shortened and thermal distortion can be reduced.
[0003]
However, since aluminum alloys have higher thermal conductivity and reflectance than steel materials and the like, it is difficult to obtain a sufficient joint strength because a deep penetration amount cannot be obtained without increasing the processing energy during welding. .
[0004]
However, simply increasing the processing energy increases the amount of penetration, but the welding process becomes unstable and spatter occurs and pores remain in the weld bead, so that stable joint strength can be obtained. However, it has been a problem in the welding of aluminum alloys with such a high energy beam to solve such a problem.
[0005]
For example, Japanese Patent Application Laid-Open No. 10-137965 discloses a method and apparatus for welding using a plurality of beams, but these are apparatuses for making a plurality of beams at a processing point, There are no considerations regarding stabilization of the welding process, such as a method of performing a plurality of processes at the same time by making a plurality of processes.
[0006]
OBJECT OF THE INVENTION
The present invention has been made by paying attention to the above-mentioned problems in conventional aluminum alloy welding technology using a high-energy beam, and can increase the processing energy while maintaining a stable welding process. It is an object of the present invention to provide a method for welding an aluminum alloy that can deepen the depth and stably obtain high joint strength.
[0007]
[Means for Solving the Problems]
The present inventors have made various studies on the irradiation conditions of the high energy beam for the purpose of solving the above problems, and as a result, the high energy beam is divided into two or more and the distance between the beams is within a predetermined range. It was found that, by holding, the welding process is stabilized by preventing mutual interference of the beams, and the amount of penetration can be increased by the synergistic action of the beams.
[0008]
Upon this invention, be based on such findings, the welding method of an aluminum alloy according to claim 1 of the present invention, the aluminum alloy is irradiated with a plurality of the same diameter and high energy beam for welding aluminum alloy When the distance at the machining point between the closest beams of the plurality of high energy beams is w and the beam diameter at the machining point of both the beams is d, the ratio w / d of both is 1.5 to The range of 2.6 is a welding configuration, and this configuration in the aluminum alloy welding method is a means for solving the above-described conventional problems.
[0009]
In the welding method according to claim 2 as an embodiment of the aluminum alloy welding method according to the present invention, when the two beams are arranged in parallel with the welding direction, the ratio w / the distance w between the beams and the beam diameter d When d is in the range of 1.5 to 2.3 and both beams are arranged in a direction substantially orthogonal to the welding progress direction, the ratio w / d is in the range of 1.5 to 2.6. As an aspect, in the aluminum alloy welding method according to claim 3, the power density of the high energy beam is set to 20000 W / mm ² or more, respectively. In the aluminum alloy welding method according to claim 4, the high energy beam is a laser. In the aluminum alloy welding method according to claim 5, the laser beam is a YAG laser beam. It is characterized by that.
[0010]
In the aluminum alloy welding method according to claim 6 as an embodiment, a plurality of laser beams are formed by transmitting laser beams oscillated from a plurality of laser oscillators through a plurality of optical fibers, respectively. In the aluminum alloy welding method according to claim 7, the laser beam oscillated from one laser oscillator and transmitted through one optical fiber is branched by a prism optical system provided in the welding head. In the welding method according to claim 8, the aluminum alloy is an alloy containing a low-boiling element such as magnesium or zinc, and the welding according to claim 9 is used. In the method, the weld joint is a lap weld joint and a high energy beam. The plate thickness on the side to be irradiated is in the range of 0.6 mm to 3.0 mm, and such a configuration in the aluminum alloy welding method is a means for solving the conventional problems described above. It is said.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
In the aluminum alloy welding method according to the present invention, when an aluminum alloy is irradiated with a high energy beam such as a laser beam or an electron beam, a plurality of beams, for example, two beams B1 and B2 as shown in FIG. While irradiating, the distance w between the two beams B1 and B2 is within a predetermined range, that is, 1.5 times the diameter d of the beam spots S1 and S2 of the two beams B1 and B2 at the processing point as shown in FIG. To 2.6 times the range, it is possible to achieve both the stabilization of the welding process and the increase of the penetration amount, and the ratio w / the distance w between the beams B1 and B2 to the beam diameter d When d is less than 1.5, the positional relationship between the beams is relatively narrow, which is close to the phenomenon when single beam welding with a large power density is performed. As a result, it becomes difficult to discharge the shield gas caught in the part, the metal gas evaporated in the molten metal is vigorously activated, and remains as a void in the weld bead or disturbs the surface of the weld bead. The strength of the part decreases. On the other hand, when the ratio w / d exceeds 2.6, the positional relationship between the beams is excessively widened, and the influence of each beam is weakened, so that a sufficient amount of penetration cannot be obtained. The strength of the weld will be reduced.
[0012]
The arrangement direction of the beams is not particularly limited. However, as described in claim 2, when both the beams B1 and B2 are parallel to or substantially parallel to the welding progress direction ( In FIG. 2 (a), the ratio w / d between the beam distance w and the beam diameter d is in the range of 1.5 to 2.3, and both the beams B1 and B2 are orthogonal to the welding direction. When the electrodes are arranged in parallel in a substantially perpendicular direction (see FIG. 2B), the ratio w / d between the inter-beam distance w and the beam diameter d may be set within a range of 1.5 to 2.6. From the viewpoint of increasing the amount of penetration and ensuring the effect of improving the strength of the welded portion.
[0013]
The welding method according to the present invention is applicable not only when there are two high energy beams, but also when the number of beams is 3, 4 or more as shown in FIGS. 3 (a) to 3 (e). In this case, the same effect can be obtained by setting the positional relationship (w / d) between the closest beams B1 and B2 of these beams to the above range.
[0014]
The power density of the high energy beam in the welding method according to the present invention is preferably 20000 W / mm ² or more as described in claim 3. That is, when the power density of each of the high energy beams irradiated to the material to be welded is less than 20000 W / mm ² , there is a tendency that a deep penetration amount cannot be obtained stably. In this case, the power density of the plurality of beams does not necessarily have to be equal.
[0015]
In the welding method of the aluminum alloy according to the present invention, there is no attenuation or spread in the atmosphere, and the laser beam can be focused at an arbitrary position by a simple optical system. It is desirable to use a YAG laser as described in claim 4 because it is desirable to use a beam, and further, the power consumption is small, the apparatus can be miniaturized, and an optical fiber can be used and handling is easy. It is desirable to apply.
[0016]
When a laser beam, particularly a YAG laser, is used as the high energy beam, as shown in FIG. 4A, for example, laser beams B1 and B2 oscillated from a plurality of laser oscillators (two in the figure) are used. Each beam is transmitted to the welding head 3 via a plurality of optical fibers 2a and 2b, and is condensed as beam spots S1 and S2 at processing points using an optical system including a collimation lens 4 and a focusing lens 5 provided in the welding head 3. As a result, the workpieces can be irradiated with a plurality of laser beams B1 and B2. Further, as shown in FIG. 4B, the laser beam B oscillated from one laser oscillator is transmitted to the welding head 3 through one optical fiber 2, and the collimation lens 4 in the welding head 3. , The beam B is divided by the semicircular prism lens 6 and further used as the focusing lens 5 to be condensed as beam spots S1 and S2 on the processing points, thereby obtaining a plurality of laser beams B1 and B2. The workpiece can be irradiated with B2. In this case, the inter-beam distance w can be controlled by moving the position of the prism lens 6 closer to or away from the focusing lens 5.
[0017]
The aluminum alloy welding method according to the present invention includes, as described in claim 8, an aluminum alloy containing an element having a lower boiling point than aluminum, such as magnesium and zinc, as an additive element, specifically JIS When applied to the specified alloy number 5000 series or 7000 series alloy, the characteristics can be utilized more effectively. That is, in high energy beam welding of materials containing such low-boiling elements, these gases evaporated in the molten metal not only destabilize the welding process but also remain as pores in the weld bead. In the conventional single beam welding, it is extremely difficult to obtain a deep penetration amount by applying high energy. However, by applying the welding method according to the present invention, it is difficult to obtain a deep penetration. Even in an aluminum alloy containing a low-boiling element, the welding process can be stably maintained, and a weld bead having a deep penetration amount can be obtained.
[0018]
The thickness of the material to be welded when the aluminum alloy welding method according to the present invention is applied to, for example, lap welding is preferably in the range of 0.6 mm to 3.0 mm as described in claim 9. It is. That is, when the material to be welded has a thickness of less than 0.6 mm, stable welding and sufficient penetration can be obtained by conventional single beam welding without applying the welding method of the present invention. In the case of a material to be welded with a thickness exceeding 0.0 mm, the weld bead penetration width at the boundary between the upper and lower plate materials is required to be 3.0 mm or more in order to obtain sufficient joint strength. In order to obtain such a welding width in a high aluminum alloy, energy is wasted, and the merit of applying high energy beam welding to lap welding is reduced.
[0019]
【The invention's effect】
Welding method of an aluminum alloy according to claim 1 of the present invention, when irradiating a plurality of the same diameter and high energy beam on the material to be welded, the ratio w of the distance w and the beam diameter d between closest beam at the processing point / D is in the range of 1.5 to 2.6, so that the welding process can be stably maintained despite the high total machining energy, and the amount of penetration of the weld becomes deeper. Therefore, it is possible to stably obtain a high joint strength.
[0020]
In the welding method according to claim 2 as an embodiment of the aluminum alloy welding method according to the present invention, the ratio of the inter-beam distance w to the beam diameter d is obtained when the two closest beams are arranged in parallel with the welding direction. When w / d is in the range of 1.5 to 2.3 and parallel in the substantially orthogonal direction, the ratio w / d is in the range of 1.5 to 2.6, so that the amount of penetration is increased. In the aluminum alloy welding method according to claim 3, the power density of the high energy beam is set to 20000 W / mm ² or more, respectively. In the aluminum alloy welding method according to claim 4, a laser beam is used as the high energy beam. Therefore, the laser beam can be easily condensed at an arbitrary position by the optical system. Further, in the welding method according to claim 5, since the YAG laser beam is used as the laser beam, the power consumption is reduced. A small and small apparatus can be used, and since an optical fiber can be used, an excellent effect that it can be handled very easily is brought about.
[0021]
Further, in the aluminum alloy welding method according to claim 6, since a plurality of laser beams are obtained by transmitting laser beams oscillated from a plurality of laser oscillators through a plurality of optical fibers, respectively. The degree of freedom of adjustment of power density, beam diameter, inter-beam distance, etc. can be increased. In the welding method according to claim 7, a plurality of laser beams are emitted from a single laser oscillator. According to the eighth aspect of the present invention, it is possible to reduce the cost of the welding apparatus by transmitting to the welding head via the optical fiber of the book and branching into a plurality by the prism optical system in the welding head. In the welding method, the aluminum alloy is an alloy containing a low-boiling element such as magnesium or zinc. Taking advantage of the characteristics of the method, it is possible to apply high energy beam welding to a material that was difficult to weld by the conventional method. In the welding method according to claim 9, the welding method according to the present invention is overlapped. Since the plate thickness on the side irradiated with the high energy beam is in the range of 0.6 mm to 3.0 mm, the advantages of lap welding of aluminum alloy using the high energy beam are maximized and the cost is reduced. An even better effect is that performance can be increased.
[0022]
【Example】
Hereinafter, the present invention will be described more specifically based on examples.
[0023]
Two aluminum alloy A5182-O materials (4.5% Mg-0.3% Mn) P1 and P2 having a plate thickness of 2.0 mm are superposed and irradiated with two laser beams B1 and B2 as high energy beams from above. Thus, the aluminum alloys P1 and P2 were lap welded, and the influence of the ratio w / d between the beam distance w and the beam diameter d on the joint strength of the obtained welded joint was investigated.
[0024]
That is, FIG. 1 (a) shows the welding situation, and as shown in FIG. 4 (a), two laser beams B1 and B2 oscillated from two YAG laser oscillators outside the figure are respectively provided. Are introduced into the welding head 3 through the optical fibers 2a and 2b, and the beam spots S1 and S2 are formed at processing points on the workpieces P1 and P2 by the optical system (collimation lens 4 and focusing lens 5) provided in the welding head 3, respectively. Welding was performed by collecting light as S2.
[0025]
At this time, the laser output from the YAG laser oscillator is 2 kW (4 kW in total), and the beam diameter d is ² (0.3 mm (about 28000 W / mm ² ) and 0.35 mm (about 20800 W / mm ² )). Standard level. As for the welding speed, when the beams B1 and B2 are brought closest to each other (w = 0.36 mm), the welding speed penetrating the two aluminum alloy materials P1 and P2 that have been superposed is obtained in advance. Fixed at 5 m / min.
[0026]
As shown in FIG. 2 (a), two beams B1 and B2 are a series beam in which the two beams B1 and B2 are arranged substantially parallel to the welding progress direction, and as shown in FIG. For each of the parallel beams in which the beams B1 and B2 are arranged in a direction almost perpendicular to the welding progress direction, the relationship with the joint strength when the inter-beam distance w is variously changed is examined.
[0027]
FIG. 5 shows this result. When the ratio w / d between the inter-beam distance w and the beam diameter d is small, the welding process becomes unstable, and the appearance of the front and back sides of the weld bead is reduced. Disturbances and vacancies were observed in the weld bead, which resulted in a slightly lower joint strength.
[0028]
On the other hand, when the ratio w / d is large, the penetration depth becomes shallow. In particular, when both beams B1 and B2 are arranged in the welding progress direction (series beam), the tendency becomes remarkable and the joint strength is reduced. The result was a significant drop. The suitable range of w / d for securing the joint strength is that the beam diameter d is 0.3 mm and 0.35 mm, and in either case, the serial beam is 1.5 to 2.3, and the parallel beam is 1 .5 to 2.6.
[Brief description of the drawings]
FIG. 1A is a perspective view showing an example of a welding situation in an aluminum welding method according to the present invention.
(B) It is an enlarged view explaining the relationship between the distance between beams in FIG. 1 (a), and a beam diameter.
FIGS. 2A and 2B are schematic explanatory views showing variations in the arrangement direction of both beams. FIG.
FIGS. 3A to 3E are schematic explanatory views showing variations in the number of beams and examples of beam arrangements.
FIG. 4A is an explanatory view showing an example of a method of forming a plurality of beams in the aluminum welding method according to the present invention.
(A) It is explanatory drawing which shows the other example of the formation method of the multiple beam in the aluminum welding method concerning this invention.
FIG. 5 is a graph showing the influence of the ratio between beam distance and beam diameter (w / d) on the joint strength in the aluminum welding method according to the present invention.
[Explanation of symbols]
2, 2a, 2b Optical fiber 3 Welding head B, B1, B2 Laser beam (high energy beam)
P1, P2 Welding material (aluminum alloy)
w Distance between beams d Beam diameter

Claims (9)

Upon the aluminum alloy is irradiated with a plurality of the same diameter and high energy beam for welding aluminum alloy,
When the distance at the processing point between the closest beams of the plurality of high energy beams is w and the beam diameter at the processing point of both the beams is d, the ratio w / d of both is 1.5-2. .6 welding method of aluminum alloy, characterized by welding in the range of When both the beams are arranged in a direction substantially parallel to the welding direction, the ratio w / d between the beam distance w and the beam diameter d is in the range of 1.5 to 2.3, and both beams are substantially orthogonal to the welding direction. 2. The aluminum alloy welding method according to claim 1, wherein the ratio w / d is in the range of 1.5 to 2.6 when paralleled in the direction. The method for welding aluminum alloy according to claim 1 or 2, wherein a power density of the high energy beam is set to 20000 W / mm ² or more. The aluminum alloy welding method according to any one of claims 1 to 3, wherein the high energy beam is a laser beam. 5. The aluminum alloy welding method according to claim 4, wherein the laser beam is a YAG laser beam. 6. The aluminum alloy welding method according to claim 5, wherein a plurality of laser beams are formed by transmitting laser beams oscillated from a plurality of laser oscillators through a plurality of optical fibers, respectively. A plurality of laser beams are formed by branching a laser beam oscillated from one laser oscillator and transmitted via one optical fiber by a prism optical system provided in a welding head. Item 6. An aluminum alloy welding method according to Item 5. The aluminum alloy welding method according to any one of claims 1 to 7, wherein the aluminum alloy is an alloy containing a low-boiling element such as magnesium or zinc. The aluminum alloy according to any one of claims 1 to 8, wherein the weld joint is a lap weld joint, and the plate thickness on the side irradiated with the high energy beam is in the range of 0.6 mm to 3.0 mm. Welding method.

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