Method for joining copper alloy sheets and joined body of copper alloy sheets

Abstract

To provide a joining method for copper alloy plate capable of joining copper alloy plates together through laser welding with high reliability, and a joint body of the copper alloy plates joined with the high reliability.SOLUTION: There is provided a joining method for copper alloy plates in which a plurality of copper alloy plates 11, 13 are joined together through laser welding, and the joining method includes: an arranging process of stacking and arranging the plurality of copper alloy plates 11, 13 together, the copper alloy plates including at least one component having a lower boiling point than copper; and a laser welding process of irradiating an irradiated part 15 having the copper alloy plates 11, 13 one over the other with laser light L along a welding direction A to join the plurality of copper alloy plates 11, 13 together, the laser light L being moved a plurality of times along a width crossing the welding direction A to make scans in the welding direction A.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a method for joining copper alloy sheets and a joined body of copper alloy sheets. [Background technology]

[0002] In general, when joining copper alloy sheets together, joining methods such as brazing and crimping are used. However, these joining methods have low productivity and increase production costs. In contrast, a joining method of laser welding copper alloy sheets together can achieve high productivity while suppressing costs.

[0003] As a technology for welding copper alloy sheets together using a laser, Patent Document 1 discloses that two or more fiber laser beams having the same focused beam diameter are irradiated onto the parts to be welded so that the center-to-center distance between the irradiated parts of each fiber laser beam is 0.7 or less of the focused beam diameter. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2014-161863 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, copper alloy sheets have high thermal conductivity and low laser light absorption, making it difficult to apply stable heat input. In particular, when laser welding thin copper alloy sheets, defects such as poor penetration and burn-through due to reflection are likely to occur, making it difficult to achieve a highly reliable joint.

[0006] Furthermore, when laser welding copper alloy sheets containing low-boiling point elements such as zinc, magnesium, or phosphorus, the low-boiling point elements are evaporated by sudden heat input, and the molten metal is blown away, which may lead to defects such as burn-through and result in a decrease in quality.

[0007] Therefore, an object of the present invention is to provide a method for joining copper alloy plates by laser welding copper alloy plates together with high reliability, and a joined body of copper alloy plates joined with high reliability. [Means for solving the problem]

[0008] The present invention comprises the following configurations. (1) A method for joining copper alloy plates by laser welding a plurality of copper alloy plates, comprising the steps of: A step of stacking and arranging a plurality of the copper alloy plates containing at least one component having a boiling point lower than the melting point of copper; a laser welding process in which a laser beam is irradiated along a welding direction to an irradiated portion where the copper alloy plates are overlapped with each other, thereby joining the plurality of copper alloy plates; Including, In the laser welding step, The laser beam is scanned in the welding direction while being moved a plurality of times in a width direction intersecting the welding direction. A method for joining copper alloy sheets. (2) A joint of copper alloy plates in which a plurality of copper alloy plates are overlapped and joined by welding at the overlapping portions, The overlapping portion is provided with a welded portion formed by solidifying molten metal, penetrating from the front to the back, The welded portion has a width dimension on the back side that is 80% or more of the width dimension on the front side. Copper alloy plate joint. Effect of the Invention

[0009] According to the present invention, copper alloy plates can be joined together by laser welding with high reliability. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 is a perspective view showing how copper alloy plates are laser-welded together. [Diagram 2] FIG. 1 is a schematic perspective view showing a laser irradiation device. [Diagram 3] FIG. 2 is a schematic plan view of copper alloy sheets with overlapping edges showing laser welding. [Figure 4] FIG. 2 is a cross-sectional view of a joint in a joint formed by joining copper alloy plates together. [Diagram 5] 1A and 1B are diagrams showing the state of a joint of a joint formed by joining copper alloy plates together, in which (A) is a schematic plan view of the laser light irradiated side, and (B) is a schematic plan view of the side opposite to the laser light irradiated side. [Figure 6] FIG. 11 is a schematic plan view of copper alloy sheets with overlapping edges, illustrating another laser welding process. [Figure 7] 1A and 1B are diagrams showing the state of a joint of a joint formed by joining copper alloy plates together, in which (A) is a schematic plan view of the laser light irradiated side, and (B) is a schematic plan view of the side opposite to the laser light irradiated side. [Figure 8] 1A and 1B are images showing the evaluation results of Example 1, in which (A) is an image of the side irradiated with laser light, (B) is an image of the side opposite to the side irradiated with laser light, and (C) is an image of a cross section at the joint. [Figure 9] 1A and 1B are images showing the evaluation results of Comparative Example 1, where (A) is an image of the side irradiated with laser light, (B) is an image of the side opposite to the side irradiated with laser light, and (C) is an image of a cross section at the joint. [Figure 10] 13 is an image showing the evaluation results of Comparative Example 2, where (A) is an image of the side irradiated with laser light, (B) is an image of the side opposite to the side irradiated with laser light, and (C) is an image of a cross section at the joint. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing how copper alloy plates 11 and 13 are laser-welded to each other.

[0012] 1, the method for joining copper alloy plates according to this embodiment is a method for joining, by laser welding, a plurality of copper alloy plates 11, 13. In this example, the case where two copper alloy plates 11, 13 are joined is illustrated.

[0013] The copper alloy plates 11 and 13, which are the objects to be joined, are partly overlapped with each other, and this overlapped part is the irradiated part 15. Then, the irradiated part 15 is irradiated with laser light L by the laser irradiation device 100, and is laser welded and joined to each other.

[0014] FIG. 2 is a schematic perspective view showing the laser irradiation device 100. As shown in FIG. 2, a laser irradiation device 100 that irradiates an irradiated portion 15 with a laser beam L is equipped with a galvanometer scanner unit, and has a galvanometer mirror 101 and an fθ lens 103. In this laser irradiation device 100, a fiber laser output from a fiber laser oscillator (not shown) is reflected by the galvanometer mirror 101, and is condensed through the fθ lens 103 to irradiate the irradiated portion 15. According to this laser irradiation device 100, by controlling the angle of the galvanometer mirror 101 attached to a rotating shaft, it is possible to scan the laser beam L at high speed and with high accuracy.

[0015] The copper alloy sheets 11 and 13 to be joined together are sheets made of a copper alloy containing at least one component having a boiling point lower than the melting point of copper (Cu). The component having a boiling point lower than the melting point of copper (Cu) contained in the copper alloy sheets 11 and 13 is zinc (Zn), magnesium (Mg) or phosphorus (P). These copper alloy sheets 11 and 13 are thin sheets having a thickness of 0.1 mm to 1.0 mm. The thickness of each of the copper alloy sheets 11 and 13 may be the same, or one of them may be thicker than the other.

[0016] Next, a method for joining copper alloy sheets according to this embodiment will be described. Fig. 3 is a schematic plan view of the copper alloy sheets 11 and 13 with overlapping edges, showing the state of laser welding. Fig. 4 is a cross-sectional view of a joint in a joined body 25 in which the copper alloy sheets 11 and 13 are joined together. Fig. 5 is a view showing the state of the joint in the joined body 25 in which the copper alloy sheets 11 and 13 are joined together.

[0017] (Placement process) 3, the copper alloy sheets 11 and 13 to be joined are arranged so as to overlap each other. In this example, the edges of the copper alloy sheets 11 and 13 are overlapped. In this way, the copper alloy sheets 11 and 13 are provided with an irradiated portion 15 consisting of the overlapped portions.

[0018] (Laser welding process) Next, the laser irradiation device 100 irradiates the irradiated portion 15 of the copper alloy plates 11, 13 with laser light L, and scans the irradiated portion 15 along a welding direction A from one end 15a to the other end 15b.

[0019] At this time, the laser irradiation device 100 is subjected to a wobbling operation, whereby the laser light L is scanned in the welding direction A while periodically rotating. Then, the laser light L is irradiated to the irradiated portion 15 in a spiral manner such that the spirals R overlap each other along the welding direction A. As a result, the laser light L scans the irradiated portion 15 in the welding direction A while moving multiple times with a turning radius D in the width direction intersecting with the welding direction A. As a result, the irradiated portions 15 of the copper alloy plates 11, 13 are heated and welded in stages by the laser light L.

[0020] In this way, when the laser irradiation device 100 is subjected to a wobbling operation to perform laser welding, as shown in Fig. 4, the irradiated portion of the copper alloy plates 11, 13 melts and fuses with each other at the joint between the copper alloy plates 11, 13, and melts up to the back surface of the copper alloy plate 13 on the side opposite to the side irradiated with the laser light L. Then, the molten portion is cooled and solidified and hardened to form a welded portion 21, which joins the copper alloy plates 11, 13, and a joint 25 of these copper alloy plates 11, 13 is obtained.

[0021] In the welded portion 21 of the joined body 25 of the copper alloy plates 11 and 13, a bead Ba is formed on the side irradiated with the laser light L, and a bead Bb is formed on the side opposite to the side irradiated with the laser light L. The width dimension WBb of the bead Bb formed on the side opposite to the side irradiated with the laser light L is 80% or more of the width dimension WBa of the bead Ba formed on the surface of the copper alloy plate 11 on the side irradiated with the laser light L.

[0022] 5(A), in a bead Ba on the side of the joint 25 irradiated with the laser light L, the laser light L is rotated to form a plurality of annular weld marks MRa that are continuous in the welding direction A. Similarly, in a bead Bb on the opposite side to the side of the joint 25 irradiated with the laser light L, the laser light L is rotated to form a plurality of annular weld marks MRb that are continuous in the welding direction A.

[0023] Thus, according to the method for joining copper alloy sheets of the present invention, when the laser light L is irradiated to the overlapping portion of the copper alloy sheets 11, 13 along the welding direction A, the laser light L is moved multiple times in the width direction intersecting with the welding direction A while being scanned in the welding direction A. This allows the irradiated portion 15 consisting of the overlapping portion of the copper alloy sheets 11, 13 to be heated and welded stepwise by the laser light L. In other words, since the heat input can be finely controlled, it is possible to suppress the occurrence of welding defects such as blowholes, cracks, or burn-through due to the sudden evaporation of the alloy composition while suppressing poor penetration due to reflection, etc. In addition, by suppressing rapid heating and cooling, it is possible to reduce the occurrence of cracks. In other words, it is possible to laser-weld and join the copper alloy sheets 11, 13, which have high thermal conductivity and low absorptance of the laser light L, to each other, with high reliability, with which it is difficult to apply stable heat input.

[0024] Therefore, even if the component having a boiling point lower than the melting point of copper contained in the copper alloy sheet is zinc, magnesium, phosphorus, or the like, the occurrence of welding defects due to the sudden evaporation of these alloy components can be suppressed, and the copper alloy sheets can be joined by laser welding with high reliability.

[0025] In particular, by scanning the laser light L in the welding direction A while periodically moving it in the width direction intersecting the welding direction, it is possible to ensure time for the molten metal to solidify and promote the escape of air bubbles that have formed in the molten metal.

[0026] Specifically, by wobbling the laser light L and rotating the irradiation position while scanning it in the welding direction A, the heat input to the welding point can be controlled more precisely, and sufficient heat input can be ensured while suppressing rapid evaporation of the alloy composition.

[0027] As a result, even if the copper alloy plates 11 and 13 to be joined together are thin plates having a thickness of 0.1 mm to 1.0 mm, they can be joined by laser welding with high reliability.

[0028] The joined body 25 of copper alloy plates obtained by the joining method of the present invention has a welded portion 21 penetrating from the front to the back at the overlapping portion of the multiple copper alloy plates 11, 13. The welded portion 21 has a width dimension WBb on the back side that is 80% or more of the width dimension WBa on the front side. Therefore, a joined body 25 in which the overlapping portions of the multiple copper alloy plates 11, 13 are joined in a well-balanced manner with high strength by the welded portion 21 can be obtained.

[0029] In addition, since the beads Ba, Bb on the front and back of the welded portion 21 have multiple annular weld marks MRa, MRb that are connected in the welding direction A, by irradiating the laser light L in a wobbling manner, it is possible to confirm that the joint 25 is welded with high strength in a balanced manner, making it easier to control the quality.

[0030] The above-mentioned joining method is suitable for manufacturing a vapor chamber having a hollow portion formed therein, for example, by overlapping a flat copper alloy plate on a concave copper alloy plate and laser welding the outer periphery to join them.

[0031] In the above example, the embodiment in which the two copper alloy plates 11 and 13 are joined has been described, but the present invention is not limited to this embodiment and can also be applied to the case in which three or more copper alloy plates are joined.

[0032] In addition, in the above example, in the laser welding process, the laser irradiation device 100 was subjected to a wobbling operation, but the laser light L may be scanned in the welding direction A while moving multiple times in the width direction intersecting with the welding direction A by a weaving operation other than the wobbling operation.

[0033] Specifically, as shown in Fig. 6, in the laser welding process, the laser irradiation device 100 is subjected to a weaving operation, so that the laser light L is periodically reciprocated in a width direction intersecting with the welding direction A with a width dimension W. In this case as well, the irradiated portions 15 of the copper alloy plates 11, 13 are gradually heated by the laser light L and welded.

[0034] In this way, even when laser welding is performed by performing the weaving operation of the laser irradiation device 100, the irradiated portion of the copper alloy plates 11, 13 melts and fuses with each other at the joint between the copper alloy plates 11, 13, and melts up to the back surface of the copper alloy plate 13 on the side opposite to the side irradiated with the laser light L (see FIG. 4). Then, the molten portion is cooled and solidified and hardened to form a welded portion 21, which joins the copper alloy plates 11, 13, and a joint 25 of these copper alloy plates 11, 13 is obtained.

[0035] In the welded portion 21 of the joint 25 of the copper alloy plates 11, 13, the width dimension WBb of the bead Bb formed on the side opposite to the side irradiated with the laser light L is 80% or more of the width dimension WBa of the bead Ba formed on the surface of the copper alloy plate 11 on the side irradiated with the laser light L.

[0036] 7A, a wavy weld mark MWa is formed along the welding direction A in a bead Ba on the side of the joint 25 irradiated with the laser light L by reciprocating the laser light L in a direction intersecting the welding direction A. Similarly, as shown in FIG 7B, a wavy weld mark MWb is formed along the welding direction A in a bead Bb on the opposite side of the joint 25 to the side irradiated with the laser light L by reciprocating the laser light L in a direction intersecting the welding direction A.

[0037] In this case, too, by weaving and periodically moving the irradiation position in the width direction intersecting the welding direction A while scanning it in the welding direction A, the heat input to the welded area can be controlled more precisely, and sufficient heat input can be ensured while suppressing rapid evaporation of the alloy composition.

[0038] The welded portion 21 of the resulting joined body 25 of copper alloy plates has a width WBb on the back side that is 80% or more of the width WBa on the front side. Therefore, the joined body 25 in which the overlapping portions of the multiple copper alloy plates 11, 13 are joined in a well-balanced manner with high strength by the welded portion 21 can be obtained.

[0039] In addition, since the beads Ba, Bb on the front and back of the welded portion 21 have wavy weld marks MWa, MWb extending along the welding direction A, it can be confirmed that the welded body 25 has been welded and joined in a balanced manner with high strength by irradiating the laser light L in a weaving manner, making it easier to control the quality. EXAMPLES

[0040] Two copper alloy sheets 11 and 13 having the same composition and thickness were stacked together and laser-welded by a laser irradiation device equipped with a galvano scanner unit to produce a joint, and the front, back and cross section of the welded part of the joint were observed and evaluated. The copper alloy sheets 11 and 13 were (Ni,Fe)-P-based copper alloys having a thickness of 0.15 mm.

[0041] <Welding conditions> Example 1 Laser welding was performed in one direction while wobbling the laser at a laser power of 3.8 kW and a scanning speed of 10 m / min. The wobbling motion had a rotation diameter of 0.6 mm and a rotation frequency of 250 Hz. Comparative Example 1 Laser welding was performed linearly along one welding direction with a laser power of 4.7 kW and a scanning speed of 20 m / min. Comparative Example 2 Laser welding was performed linearly along one welding direction with a laser power of 4.5 kW and a scanning speed of 20 m / min.

[0042] <Evaluation Results> 8 to 10 are images showing the evaluation results of Example 1, Comparative Example 1, and Comparative Example 2. In each figure, (A) is an image of the side irradiated with the laser light, (B) is an image of the side opposite to the side irradiated with the laser light, and (C) is an image of a cross section at the joint.

[0043] Example 1 In Example 1, as shown in Fig. 8(A), a bead Ba was formed on the surface of the copper alloy plate 11 on the side irradiated with the laser light, and multiple annular weld marks MRa were formed on this bead Ba by rotating the laser light. Also, as shown in Fig. 8(B), a bead Bb was formed on the surface of the copper alloy plate 13 on the side opposite to the side irradiated with the laser light, and multiple annular weld marks MRb were also formed on this bead Bb by rotating the laser light. Also, there was no sign of burn-through on the beads Ba and Bb.

[0044] In Example 1, as shown in Fig. 8(C), a welded portion 21 was formed penetrating the joint between the copper alloy plates 11 and 13 in the thickness direction. In this welded portion 21, the width dimension WBa of the bead Ba formed on the copper alloy plate 11 side was 0.80 mm, and the width dimension WBb of the bead Bb formed on the copper alloy plate 13 side was 0.69 mm. Therefore, the width dimension WBb of the bead Bb was 86% of the width dimension WBa of the bead Ba. In other words, the width dimension WBb was 80% or more of the width dimension WBa, and the welded portion 21 was formed without deviation in the copper alloy plates 11 and 13.

[0045] Comparative Example 1 In Comparative Example 1, as shown in Fig. 9A, a linear bead Ba was formed along the scanning direction of the laser light on the surface of the copper alloy plate 11 on the side irradiated with the laser light. Also, as shown in Fig. 9B, a linear bead Bb was formed along the scanning direction of the laser light on the surface of the copper alloy plate 13 on the opposite side to the side irradiated with the laser light. However, these beads Ba and Bb were melted through (part F in Fig. 9A and Fig. 9B), probably because heat was suddenly input by the laser light.

[0046] In Comparative Example 1, as shown in Fig. 9(C), a welded portion 21 penetrating in the thickness direction was formed at the joint between the copper alloy plates 11 and 13. In this welded portion 21, the width dimension WBa of the bead Ba formed on the copper alloy plate 11 side was 0.66 mm, and the width dimension WBb of the bead Bb formed on the copper alloy plate 13 side was 0.48 mm. Therefore, the width dimension WBb of the bead Bb was 72% of the width dimension WBa of the bead Ba. In other words, the width dimension WBb was less than 80% of the width dimension WBa, and the welded portion 21 was formed unevenly at the joint between the copper alloy plates 11 and 13.

[0047] Comparative Example 2 In Comparative Example 2, as shown in Fig. 10(A), a linear bead Ba was formed along the scanning direction of the laser light on the surface of the copper alloy sheet 11 on the side irradiated with the laser light. However, as shown in Fig. 10(B), a bead Bb was not formed on the surface of the copper alloy sheet 13 on the opposite side to the side irradiated with the laser light.

[0048] 10(C), in the joint between the copper alloy plates 11 and 13, a welded portion 21 was formed in the copper alloy plate 11 on the laser light irradiated side. However, probably due to insufficient output of the laser light L, the welded portion 21 hardly reached the copper alloy plate 13 and was not melted into the copper alloy plate 13.

[0049] As such, the present invention is not limited to the above-described embodiments, and the present invention also contemplates mutual combinations of the various components of the embodiments, as well as modifications and applications by those skilled in the art based on the descriptions in the specification and well-known technologies, and these are included in the scope of protection sought.

[0050] As described above, the present specification discloses the following: (1) A method for joining copper alloy plates by laser welding a plurality of copper alloy plates, comprising the steps of: A step of stacking and arranging a plurality of the copper alloy plates containing at least one component having a boiling point lower than the melting point of copper; a laser welding process in which a laser beam is irradiated along a welding direction to an irradiated portion where the copper alloy plates are overlapped with each other, thereby joining the plurality of copper alloy plates; Including, In the laser welding step, The method for joining copper alloy sheets includes scanning the laser light in the welding direction while moving the laser light multiple times in a width direction intersecting the welding direction. According to the method for joining copper alloy sheets having this configuration, when the overlapping portions of the copper alloy sheets are irradiated with a laser beam along the welding direction, the laser beam is moved multiple times in the width direction intersecting with the welding direction while being scanned in the welding direction. This allows the overlapping portions of the copper alloy sheets to be heated and welded stepwise by the laser beam. In other words, since the heat input can be finely controlled, it is possible to suppress the occurrence of welding defects such as blowholes, cracks, or burn-through caused by the rapid evaporation of the alloy composition while suppressing poor penetration caused by reflection, etc. In addition, by suppressing rapid heating and cooling, it is possible to reduce the occurrence of cracks. In other words, it is possible to laser-weld and join copper alloy sheets, which have high thermal conductivity and low laser beam absorption rate, to which stable heat input is difficult to apply, with high reliability.

[0051] (2) The method for joining copper alloy sheets according to (1), wherein the component having a boiling point lower than the melting point of copper contained in the copper alloy sheets is zinc, magnesium or phosphorus. According to the method for joining copper alloy sheets having this configuration, the occurrence of welding defects due to the sudden evaporation of alloy components such as zinc, magnesium, or phosphorus can be suppressed, and copper alloy sheets can be joined by laser welding with high reliability.

[0052] (3) The method for joining copper alloy sheets according to (1) or (2), wherein in the laser welding step, the laser light is scanned in the welding direction while being periodically moved in a width direction intersecting the welding direction. According to the method for joining copper alloy sheets having this configuration, the laser light is periodically moved in the width direction intersecting the welding direction while being scanned in the welding direction, thereby ensuring time for the molten metal to solidify and promoting the escape of bubbles generated in the molten metal.

[0053] (4) The method for joining copper alloy sheets according to any one of (1) to (3), wherein in the laser welding step, the laser light is wobbled to rotate an irradiation position while scanning in the welding direction. According to the method for joining copper alloy sheets having this configuration, the laser light is wobbled and rotated to scan the irradiation position in the welding direction, thereby making it possible to more precisely control the heat input to the welding point and ensure a sufficient amount of heat input while suppressing rapid evaporation of the alloy composition.

[0054] (5) The method for joining copper alloy sheets according to any one of (1) to (3), wherein, in the laser welding step, the laser beam is weaved to scan the laser beam in the welding direction while periodically moving an irradiation position in a width direction intersecting the welding direction. According to the method for joining copper alloy sheets having this configuration, by weaving and periodically moving the irradiation position in the width direction intersecting the welding direction while scanning it in the welding direction, the heat input to the welding point can be controlled more finely, and a sufficient amount of heat input can be secured while suppressing rapid evaporation of the alloy composition.

[0055] (6) The method for joining copper alloy sheets according to any one of (1) to (5), wherein the copper alloy sheets to be joined together are thin sheets having a thickness of 0.1 mm to 1.0 mm. According to the method for joining copper alloy sheets having this configuration, even if the copper alloy sheets to be joined are thin sheets having a thickness of 0.1 mm to 1.0 mm, they can be joined by laser welding with high reliability.

[0056] (7) A joint of copper alloy plates in which a plurality of copper alloy plates are overlapped and joined by welding at the overlapping portions, The overlapping portion is provided with a welded portion formed by solidifying molten metal, penetrating from the front to the back, A joint of copper alloy plates, wherein the welded portion has a width dimension on the back surface side that is 80% or more of the width dimension on the front surface side. According to the joined body of copper alloy sheets having this configuration, the overlapping portions of the multiple copper alloy sheets have a welded portion penetrating from the front to the back. The width dimension of this welded portion on the back side is 80% or more of the width dimension on the front side. Therefore, a joined body in which the overlapping portions of the multiple copper alloy sheets are joined in a balanced manner with high strength by the welded portion can be obtained.

[0057] (8) A bead is formed on the front and back of the weld along the welding direction, The joined body of copper alloy sheets according to (7), wherein each of the beads has a plurality of annular weld marks formed in a continuous manner in the welding direction. According to the joined copper alloy plates having this configuration, the beads on the front and back of the welded portion have a plurality of annular weld marks that are continuous in the welding direction. Therefore, for example, by irradiating the welded portion with a wobbling laser beam, it is possible to confirm that the joined body is welded with high strength in a balanced manner, which makes it easy to control the quality.

[0058] (9) A bead is formed on the front and back of the weld along the welding direction, The joined body of copper alloy sheets according to (7), wherein each of the beads has a wavy weld mark formed along the welding direction. In the joined copper alloy plates having this configuration, the beads on the front and back of the welded portion have wavy weld marks along the welding direction. Therefore, for example, by irradiating the weaving laser light, it can be confirmed that the joined body is welded with high strength in a balanced manner, and quality control becomes easy. [Explanation of symbols]

[0059] 11,13 Copper alloy plate 15 Irradiated area 21 Welding 25 Zygote A Welding direction Ba,Bb Bead L Laser light WBa, WBb width dimensions MRa,MRb Circular weld mark MWa, MWb Wavy weld marks

Claims

1. A method for joining copper alloy plates by laser welding a plurality of copper alloy plates together, comprising the steps of: A step of stacking and arranging a plurality of the copper alloy plates containing at least one component having a boiling point lower than the melting point of copper; a laser welding process in which a laser beam is irradiated along a welding direction to an irradiated portion where the copper alloy plates are overlapped with each other, thereby joining the plurality of copper alloy plates; Including, In the laser welding step, The laser beam is moved a plurality of times in a width direction intersecting the welding direction while being scanned in the welding direction, so that a welded portion in which molten metal is solidified is provided in a portion where the plurality of copper alloy sheets are overlapped, penetrating from the front to the back, and the width dimension of the welded portion on the back side is set to 80% or more of the width dimension on the front side in the width direction. A method for joining copper alloy plates.

2. The component having a boiling point lower than the melting point of copper contained in the copper alloy plate is zinc, magnesium or phosphorus. The method for joining copper alloy sheets according to claim 1.

3. In the laser welding step, the laser light is scanned in the welding direction while being periodically moved in the width direction. The method for joining copper alloy sheets according to claim 1 or 2.

4. In the laser welding step, the laser light is wobbled to rotate an irradiation position while scanning in the welding direction. The method for joining copper alloy sheets according to any one of claims 1 to 3.

5. In the laser welding step, the laser light is weaved to periodically move an irradiation position in a width direction intersecting the welding direction while scanning the laser light in the welding direction. The method for joining copper alloy sheets according to any one of claims 1 to 3.

6. The copper alloy plates to be joined together are thin plates having a thickness of 0.1 mm to 1.0 mm; The method for joining copper alloy sheets according to any one of claims 1 to 5.

7. A joint of copper alloy plates in which a plurality of copper alloy plates containing at least one component having a boiling point lower than the melting point of copper are overlapped and joined together at overlapping portions, The overlapping portion is provided with a laser welded portion formed by solidifying molten metal, penetrating from the front to the back, The laser welded portion has a width dimension on the back side in a width direction intersecting with the welding direction on the front side that is 80% or more of the width dimension in the width direction on the back side. Copper alloy plate joint.

8. Beads are formed on the front and back of the laser welded portion along the welding direction, Each of the beads has a plurality of annular weld marks formed in a continuous manner in the welding direction. A joined body of copper alloy sheets according to claim 7.

9. Beads are formed on the front and back of the laser welded portion along the welding direction, Each of the beads has a wavy weld mark formed along the welding direction. A joined body of copper alloy sheets according to claim 7.

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