JP7608074B2 - Welding method and welding equipment - Google Patents

Description

The present invention relates to a welding method and a welding apparatus .

Conventionally, a vapor chamber has been known in which a chamber for storing a refrigerant is provided between two overlapping plate-shaped metal members, and the periphery of the two metal members is welded to seal the refrigerant (for example, Patent Document 1).

JP 2016-35348 A

In the vapor chamber of Patent Document 1, the two plate-shaped members are joined by laser light irradiated along the stacking direction. With this type of configuration, for example, a flange is provided that protrudes in the extension direction of the plate-shaped members, which is the width direction of the welded area, and this can lead to the metal members and therefore the vapor chamber becoming larger in the extension direction of the plate-shaped members.

On the other hand, in a vapor chamber in which two plate-shaped members are welded together using laser light irradiated toward the boundary between the two members in the direction in which the plate-shaped members extend, the width of the welded area expands in the stacking direction of the plate-shaped members. In this case, there are issues such as difficulty in application to thin plate thicknesses, and the weld depth being too short when the weld width is matched to the plate thickness, making it difficult to ensure the required weld strength.

Therefore, one of the objectives of the present invention is to provide a new and improved welding method and welding apparatus capable of welding, for example, multiple overlapping members, as well as a product welded by the welding method or welding apparatus.

In the welding method of the present invention, for example, a laser beam emitted from a laser oscillator including a fiber laser is irradiated from the outside of each end of a plurality of members overlapping in a first direction, the ends of which are aligned in the first direction and extend in a second direction intersecting the first direction, along a third direction intersecting the first and second directions, thereby welding the ends adjacent to each other in the first direction, and the wavelength of the laser beam is 380 nm or more and 1200 nm or less.

In the welding method, for example, the laser light includes a first laser light having a wavelength of 800 nm or more and 1200 nm or less, and a second laser light having a wavelength of 500 nm or less.

In the welding method, for example, the wavelength of the second laser light is 400 nm or more and 500 nm or less.

In the welding method, for example, the second laser light is irradiated so as to span the gap at the boundary between the edges adjacent in the first direction in the first direction.

In the welding method, for example, the laser light is swept in a sweep direction along the second direction on a surface of the end portion extending in the first direction and the second direction, and at least a portion of the second spot formed on the surface by the second laser light is located forward in the sweep direction of the first spot formed on the surface by the first laser light.

In the welding method, for example, the first spot and the second spot at least partially overlap on the surface.

In the welding method, for example, on the surface, the second outer edge of the second spot surrounds the first outer edge of the first spot.

In the welding method, for example, each of the plurality of components is made of any one of a copper-based metal material, an aluminum-based metal material, a nickel-based metal material, an iron-based metal material, and a titanium-based metal material.

The welding device of the present invention includes, for example, a laser oscillator including a fiber laser, and an optical head that irradiates laser light emitted from the laser oscillator to ends of a plurality of members overlapping in a first direction, the ends of which extend in a second direction intersecting with the first direction and are aligned in the first direction, from the outside of the ends along a third direction intersecting with the first and second directions, and welds the edges adjacent to each other in the first direction, and the wavelength of the laser light is 380 nm or more and 1200 nm or less.

The welding device may, for example, be equipped with a beam shaper that splits the laser light into multiple beams.

The welding device, for example, includes a galvanometer scanner that changes the emission direction of the laser light so that the laser light moves in a sweeping direction along the second direction on a surface of the end portion that extends in the first direction and the second direction.

The welding device, for example, includes a rotation mechanism that rotates the end portion around a rotation axis along the first direction.

The welding device includes, for example, a detection mechanism that detects the deviation of the spot formed on the surface by the laser light from a predetermined position, and a correction mechanism that corrects the deviation.

The product of the present invention includes, for example, a plurality of members each having an edge extending in a second direction, overlapping in a first direction with the edges aligned in the first direction intersecting with the second direction, and a welded portion in which the edges of adjacent members in the first direction among the plurality of members are welded together, the welded portion having a weld metal extending from a surface extending in the first direction and the second direction of an end portion including the edge adjacent to the first direction to a third direction intersecting with the first direction and the second direction, and a heat-affected zone located around the weld metal, the weld metal having a first portion and a second portion having a larger average cross-sectional area of crystal grains in a cross section intersecting with the second direction than the first portion.

In the product, for example, the average cross-sectional area of the crystal grains contained in the second portion is 1.8 times or more the average cross-sectional area of the crystal grains contained in the first portion.

In the product, for example, the weld metal extends in the second direction.

In the product, for example, the aspect ratio of the weld metal's depth in the third direction to its width in the first direction is 1 or more and 5 or less.

In the above product, for example, the aspect ratio is greater than or equal to 1.5 and less than or equal to 5.

The product includes, for example, a first member and a second member joined to the first member with a space formed between the first member and the second member, and the first member and the second member are joined as the multiple members by the welds.

The product includes, for example, a first member and a second member indirectly joined to the first member via a third member with a space formed between the first member and the second member, and at least one of the first member and the third member, and the second member and the third member, is joined as the plurality of members by the welded portion.

The product, for example, includes a fluid medium contained within the space, and the multiple components are welded together in a manner that prevents the fluid medium from leaking out of the space from the weld.

The product of the present invention, for example, comprises a plurality of members each having an edge extending in a second direction, the edges of which are aligned in a first direction intersecting with the second direction, and constituting an end portion overlapping in the first direction, and a welded portion formed by welding the edges of adjacent members of the plurality of members in the first direction together, the welded portion extending in the second direction and exposed at a distance from both ends of the end portion in the first direction when the end portion is viewed from the outside of the end portion along a third direction intersecting with the first direction and the second direction.

In the product, for example, the welded portion has a weld metal extending from a surface extending in the first direction and the second direction of an end portion including the edge adjacent to the first direction to a third direction intersecting the first direction and the second direction, and a heat-affected zone located around the welded metal, and the aspect ratio of the depth of the welded metal in the third direction to the width in the first direction is 1 or more and 5 or less.

In the above product, for example, the aspect ratio is greater than or equal to 1.5 and less than or equal to 5.

The present invention provides a new and improved welding method and welding apparatus capable of welding, for example, multiple overlapping members, as well as a product welded by the welding method or welding apparatus.

FIG. 1 is an exemplary schematic configuration diagram of a laser welding apparatus according to a first embodiment. FIG. 2 is a schematic side view showing an example of a holding mechanism for an object to be processed that is included in the laser welding apparatus of the first embodiment. FIG. 3 is a schematic plan view showing an example of a holding mechanism for an object to be processed that is included in the laser welding apparatus of the first embodiment. FIG. 4 is an exemplary schematic diagram showing a beam (spot) of laser light formed on the surface of an object to be processed by the laser welding apparatus of the first embodiment. FIG. 5 is a graph showing the light absorptance of each metal material versus the wavelength of the irradiated laser light. FIG. 6 is an exemplary schematic cross-sectional view of a welded portion according to an embodiment. FIG. 7 is an exemplary schematic cross-sectional view showing a portion of a welded portion of the embodiment. FIG. 8 is a schematic side view showing an example of a holding mechanism for an object to be processed that is included in the laser welding apparatus of the first embodiment. FIG. 9 is an exemplary schematic configuration diagram of a laser welding device according to the second embodiment. FIG. 10 is an explanatory diagram showing the concept of the principle of the diffractive optical element included in the laser welding apparatus of the second embodiment. FIG. 11 is an exemplary schematic configuration diagram of a laser welding device according to the third embodiment. FIG. 12 is an exemplary schematic configuration diagram of a laser welding device according to the fourth embodiment. FIG. 13 is an exemplary schematic configuration diagram of a laser welding device according to the fifth embodiment. FIG. 14 is a schematic diagram showing an example of a laser light beam (spot) formed on the surface of the object to be processed by the laser welding apparatus of the fifth embodiment. FIG. 15 is a schematic diagram showing an example of a laser light beam (spot) formed on the surface of an object to be processed by the laser welding apparatus of the fifth embodiment. FIG. 16 is an exemplary schematic perspective view of a product according to the sixth embodiment. FIG. 17 is a cross-sectional view taken along line XVII-XVII of FIG. FIG. 18 is an illustrative schematic cross-sectional view of a product according to a first modified example of the sixth embodiment. FIG. 19 is an illustrative schematic cross-sectional view of a product according to a second modified example of the sixth embodiment. FIG. 20 is an illustrative schematic cross-sectional view of a product according to a third modified example of the sixth embodiment. FIG. 21 is an illustrative schematic exploded perspective view of a product according to a fourth modified example of the sixth embodiment. FIG. 22 is an illustrative schematic cross-sectional view of a product according to a fourth modified example of the sixth embodiment. FIG. 23 is an exemplary schematic configuration diagram of a laser welding device according to the seventh embodiment.

Below, exemplary embodiments and variations of the present invention are disclosed. The configurations of the embodiments and variations shown below, and the actions and results (effects) brought about by said configurations, are merely examples. The present invention can also be realized by configurations other than those disclosed in the following embodiments and variations. Furthermore, according to the present invention, it is possible to obtain at least one of the various effects (including derivative effects) obtained by the configurations.

The embodiments and modified examples shown below have similar configurations. Therefore, according to the configurations of each embodiment and modified example, similar actions and effects based on the similar configurations can be obtained. Furthermore, below, the same reference numerals are given to those similar configurations, and duplicate explanations may be omitted.

In each figure, the X direction is represented by an arrow X, the Y direction is represented by an arrow Y, and the Z direction is represented by an arrow Z. The X direction, Y direction, and Z direction intersect and are perpendicular to each other. The X direction is the sweep direction SD and also the extension direction (longitudinal direction) of the welded portion 14. The Y direction is the stacking direction and also the width direction (short direction) of the welded portion 14. The Z direction is the normal direction of the surface Wa (machined surface, welded surface) of the workpiece (welded object).

In addition, in this specification, ordinal numbers are used for convenience to distinguish between parts, members, locations, laser beams, directions, etc., and do not indicate priority or order.

[First embodiment]
Fig. 1 is a schematic configuration diagram of a laser welding apparatus 100 according to a first embodiment. As shown in Fig. 1, the laser welding apparatus 100 includes a laser device 111, a laser device 112, an optical head 120, and an optical fiber 130. The laser welding apparatus 100 is an example of a welding apparatus.

The laser devices 111 and 112 each have a laser oscillator and are configured to output laser light with a power of, for example, several kW. The laser devices 111 and 112 emit laser light with a wavelength of 380 nm or more and 1200 nm or less. The laser devices 111 and 112 each have a laser light source therein, such as a fiber laser, a semiconductor laser (element), a YAG laser, or a disk laser. The laser devices 111 and 112 may be configured to output multi-mode laser light with a power of several kW as the sum of the outputs of the multiple light sources.

The laser device 111 outputs a first laser light having a wavelength of 800 nm or more and 1200 nm or less. The laser device 111 is an example of a first laser device. As an example, the laser device 111 has a fiber laser or a semiconductor laser (element) as a laser light source. The laser oscillator of the laser device 111 is an example of a first laser oscillator.

On the other hand, the laser device 112 outputs a second laser light having a wavelength of 500 nm or less. The laser device 112 is an example of a second laser device. As an example, the laser device 112 has a semiconductor laser (element) as a laser light source. It is preferable that the laser device 112 outputs a second laser light having a wavelength of 400 nm or more and 500 nm or less. The laser oscillator of the laser device 112 is an example of a second laser oscillator.

The optical fiber 130 guides the laser light output from the laser devices 111 and 112 to the optical head 120.

The optical head 120 is an optical device for irradiating the laser light input from the laser devices 111 and 112 toward the processing object. The optical head 120 includes a collimating lens 121, a condensing lens 122, a mirror 123, and a filter 124. The collimating lens 121, the condensing lens 122, the mirror 123, and the filter 124 may also be referred to as optical components.

The optical head 120 is configured to be able to change its relative position with respect to the object to be processed in order to sweep the laser light L while irradiating the laser light L on the surface Wa of the end portion 10a as the object to be processed. The relative movement between the optical head 120 and the object to be processed can be achieved by moving the optical head 120, by moving the object to be processed, or by moving both the optical head 120 and the object to be processed.

The optical head 120 may be configured to sweep the laser light L over the surface Wa by having a galvanometer scanner (not shown) or the like.

The collimating lenses 121 (121-1, 121-2) each collimate the laser light input via the optical fiber 130. The collimated laser light becomes parallel light.

Mirror 123 reflects the first laser light that has been collimated by collimator lens 121-1. The first laser light reflected by mirror 123 travels in the opposite Z direction toward filter 124. Note that in a configuration in which the first laser light is input to optical head 120 so as to travel in the opposite Z direction, mirror 123 is not necessary.

Filter 124 is a high-pass filter that transmits the first laser light and reflects but does not transmit the second laser light. The first laser light passes through filter 124 and travels in the opposite Z direction toward collecting lens 122. On the other hand, filter 124 reflects the second laser light that has been collimated by collimating lens 121-2. The second laser light reflected by filter 124 travels in the opposite Z direction toward collecting lens 122.

The focusing lens 122 focuses the first laser light and the second laser light as parallel light, and irradiates the laser light L (output light) onto the processing target.

The object to be processed is a laminate 10 in which a first member 11 and a second member 12 are stacked in the Y direction. The laminate 10 has a first member 11, a second member 12, and a welded portion 14 where the first member 11 and the second member 12 are welded. The laminate 10 becomes a product by welding the first member 11 and the second member 12 by the welded portion 14. The first member 11 and the second member 12 each have a plate-like shape that spreads across the Y direction. The portions of the first member 11 and the second member 12 that are welded by the welded portion 14 extend in the X direction and the Z direction, respectively. The first member 11 and the second member 12 can also be referred to as plate-like members. The Y direction is an example of a first direction. The first member 11 and the second member 12 are an example of a plurality of members.

The end 10a of the laminate 10 has edges 11a and 12a. The edge 11a includes the edge 11a of the first member 11 and the edge 12a of the second member 12. The edges 11a and 12a each extend in the X direction. The edges 11a and 12a can also be referred to as end faces. The edges 11a and 12a are aligned in the Y direction. The edges 11a and 12a are substantially flush, but may have some steps. The edges 11a and 12a form the surface Wa of the end 10a that faces the optical head 120. The X direction is an example of a second direction.

The laser light L is irradiated from the outside of the end portion 10a toward the boundary between the end edges 11a and 12a in the opposite direction of the Z direction. As a result, a weld 14 is formed on the end portion 10a, extending from the surface Wa along the boundary in the opposite direction of the Z direction. In other words, the weld 14 joins the end edges 11a and 12a. The weld 14 also extends linearly in the sweep direction SD (X direction) along the surface Wa due to the laser light L sweeping the surface Wa in the sweep direction SD. The Z direction is an example of a third direction.

Figure 2 is a side view of the holding mechanism 150 of the laminate 10, and Figure 3 is a plan view of the holding mechanism 150. As shown in Figures 2 and 3, the holding mechanism 150 has a pressing member 151 and support members 152 and 153.

The pressing member 151 is, for example, a plate-shaped member that extends across the Z direction, and is made of, for example, a metal material with relatively high thermal conductivity. The two pressing members 151 are arranged to sandwich the stack 10 in the Y direction. The support members 152 and 153 are arranged to sandwich the pressing member 151 in the Z direction and hold the pressing member 151. The support members 152 and 153 hold the two pressing members 151 so that a force is applied from the two pressing members 151 to the stack 10 from both sides in the Y direction, causing the first member 11 and the second member 12 to approach each other in the Y direction. In other words, by adjusting the positions of the pressing members 151 and the support members 152 and 153 in the holding mechanism 150, the stack 10 can be set in an appropriate position and posture with respect to the laser light L.

Also, as shown in FIG. 2, in this embodiment, when the laminate 10 is viewed in the opposite direction to the Z direction, i.e., when viewed from the outside of the end 10a along the Z direction, the welded portion 14 is exposed at a distance from the ends 10a1 on both sides of the end 10a in the Y direction, and does not reach both end faces of the laminate 10 in the Y direction.

FIG. 4 is a schematic diagram showing a beam (spot) of laser light L irradiated on the surface Wa. Each of the beams B1 and B2 has, for example, a Gaussian-shaped power distribution in the radial direction of the cross section perpendicular to the optical axis direction of the beam. However, the power distribution of the beams B1 and B2 is not limited to a Gaussian shape. In addition, in each figure in which the beams B1 and B2 are represented by circles as in FIG. 4, the diameter of the circle representing the beams B1 and B2 is the beam diameter of each of the beams B1 and B2. The beam diameter of each of the beams B1 and B2 is defined as the diameter of a region including the peak of the beam and having an intensity of 1/ ^e2 or more of the peak intensity. Although not shown, in the case of a non-circular beam, the length of the region having an intensity of 1/e2 ^or more of the peak intensity in the direction perpendicular to the sweep direction SD can be defined as the beam diameter. In addition, the beam diameter on the surface Wa is called the spot diameter.

As shown in FIG. 4, in this embodiment, as an example, the beam of laser light L is formed on the surface Wa such that the beam B1 of the first laser light and the beam B2 of the second laser light overlap, the beam B2 is larger (wider) than the beam B1, and the outer edge B2a of the beam B2 surrounds the outer edge B1a of the beam B1. In this case, the spot diameter D2 of the beam B2 is larger than the spot diameter D1 of the beam B1. On the surface Wa, the beam B1 is an example of a first spot, and the beam B2 is an example of a second spot.

In addition, in this embodiment, as shown in FIG. 4, the beam (spot) of the laser light L on the surface Wa has a point-symmetric shape with respect to the center point C, so the shape of the spot is the same for any sweep direction SD. Therefore, when a moving mechanism is provided to move the optical head 120 and the workpiece relatively to sweep the laser light L on the surface Wa, the moving mechanism needs to have at least a mechanism capable of relatively translating, and a mechanism capable of relatively rotating can sometimes be omitted.

When there is a gap (not shown) at the boundary Br between the first member 11 and the second member 12, where the edges 11a, 12a are slightly separated from each other in the Y direction, the laser light L is irradiated so as to straddle the gap. As an example, the laser welding device 100 and the laminate 10 are set so that the beam B2 of the second laser light straddles the gap in the Y direction on the surface Wa. In this case, the width of the spot of the second laser light (e.g., the spot diameter D2 in FIG. 4) is larger than the width of the gap.

The first member 11 and the second member 12 to be processed can each be made of a metal material with a relatively high thermal conductivity. Examples of metal materials include copper-based metal materials, aluminum-based metal materials, nickel-based metal materials, iron-based metal materials, and titanium-based metal materials, and more specifically, copper, copper alloys, aluminum, aluminum alloys, tin, nickel, nickel alloys, iron, stainless steel, titanium, and titanium alloys. The first member 11 and the second member 12 can be made of the same material or different materials.

[Wavelength and light absorption rate]
Here, the light absorptance of metal materials will be described. Fig. 5 is a graph showing the light absorptance of each metal material versus the wavelength of the irradiated laser light L. The horizontal axis of the graph in Fig. 5 is the wavelength, and the vertical axis is the absorptance. Fig. 5 shows the relationship between wavelength and absorptance for aluminum (Al), copper (Cu), gold (Au), nickel (Ni), silver (Ag), tantalum (Ta), and titanium (Ti).

Although the characteristics differ depending on the material, it can be seen that for each metal shown in Figure 5, the energy absorption rate is higher when using blue or green laser light (second laser light) than when using general infrared (IR) laser light (first laser light). This characteristic is particularly noticeable in copper (Cu), gold (Au), etc.

When a laser beam is irradiated onto a workpiece that has a relatively low absorption rate for the wavelength being used, most of the light energy is reflected and does not affect the workpiece as heat. Therefore, a relatively high power must be applied to obtain a melted region of sufficient depth. In this case, the sudden input of energy into the center of the beam causes sublimation and the formation of a keyhole.

On the other hand, when a laser beam is irradiated onto a workpiece that has a relatively high absorption rate for the wavelength used, most of the input energy is absorbed by the workpiece and converted into thermal energy. In other words, since there is no need to apply excessive power, no keyhole is formed and the melting occurs by thermal conduction.

In this embodiment, the wavelength of the first laser light, the wavelength of the second laser light, and the material of the object to be processed are selected so that the absorptance of the second laser light by the object to be processed is higher than the absorptance of the first laser light. In this case, when the sweep direction is the sweep direction SD shown in FIG. 5, the second laser light is first irradiated to the part of the object to be welded (hereinafter referred to as the welded part) by the sweep of the spot of the laser light L by the region B2f of the beam B2 of the second laser light located in front of SD in FIG. 5. Then, the welded part is irradiated with the beam B1 of the first laser light, and then the second laser light is irradiated again by the region B2b of the beam B2 of the second laser light located behind the sweep direction SD.

Therefore, a thermal conduction type melting region is first generated in the welded area by irradiation of the second laser light, which has a high absorption rate, in the area B2f. Then, a deeper keyhole type melting region is generated in the welded area by irradiation of the first laser light. In this case, since a thermal conduction type melting region is already formed in the welded area, a melting region of the required depth can be formed by a lower power first laser light compared to a case where the thermal conduction type melting region is not formed. Then, the melted state of the welded area changes by irradiation of the second laser light, which has a high absorption rate, in the welded area B2b.

In addition, experimental research by the inventors has confirmed that welding defects such as spatters and blowholes can be reduced when welding is performed by irradiating the laser light L of the beam as shown in FIG. 4. This is presumably because the molten pool of the workpiece formed by beam B2 and beam B1 becomes more stable by preheating the workpiece by region B2f of beam B2 before beam B1 arrives.

[Welding method]
In welding using the laser welding device 100, first, the laminate 10 is set in the holding mechanism 150 so that the laser light L is irradiated onto the surface Wa. Then, while the laser light L including the beam B1 and the beam B2 is irradiated onto the surface Wa, the laser light L and the laminate 10 (holding mechanism 150) are moved relative to each other. As a result, the laser light L moves (sweeps) on the surface Wa in the sweep direction SD while being irradiated onto the surface Wa. The portion irradiated with the laser light L melts and then solidifies as the temperature decreases, thereby welding the first member 11 and the second member 12 together, and the laminate 10 is integrated.

[Cross section of welded part]
6 is a cross-sectional view of a welded portion 14 formed on a processing object W. FIG. 6 is a cross-sectional view perpendicular to the sweep direction SD (X direction) and along the thickness direction (Z direction). The welded portion 14 extends in the sweep direction SD, i.e., in a direction perpendicular to the paper surface of FIG. 6. FIG. 6 shows a cross-section of the welded portion 14 formed on the processing object W, which is a single copper plate having a thickness of 2 mm. It can be assumed that the shape of the welded portion 14 formed on the multiple plate-shaped metal materials stacked in the Y direction is substantially the same as the shape of the welded portion 14 formed on the processing object W, which is a single metal material, shown in FIG. 6.

As shown in FIG. 6, the welded portion 14 has a weld metal 14a extending from the surface Wa in the opposite direction to the Z direction, and a heat-affected zone 14b located around the welded metal 14a. The welded metal 14a is a portion that melts when irradiated with laser light L and then solidifies. The welded metal 14a can also be referred to as a molten solidification zone. The heat-affected zone 14b is a portion of the base material to be processed that is thermally affected but does not melt.

The width of the weld metal 14a in the Y direction becomes narrower as it moves away from the surface Wa. In other words, the cross section of the weld metal 14a has a tapered shape that becomes narrower in the opposite direction to the Z direction.

Furthermore, detailed analysis of the cross section by the inventors revealed that the weld metal 14a includes a first portion 14a1 that is separated from the surface Wa, and a second portion 14a2 that is between the first portion 14a1 and the surface Wa.

The first portion 14a1 is a portion obtained by melting in a keyhole shape by irradiation with the first laser light, and the second portion 14a2 is a portion obtained by melting by irradiation of the region B2b located behind the sweep direction SD of the second laser light beam B2. Analysis using the electron back scattered diffraction pattern (EBSD) method revealed that the sizes of the crystal grains in the first portion 14a1 and the second portion 14a2 are different, and specifically, in a cross section perpendicular to the X direction (sweep direction SD), the average cross-sectional area of the crystal grains in the second portion 14a2 is larger than the average cross-sectional area of the crystal grains in the first portion 14a1.

The inventors confirmed that when the workpiece W is irradiated with only the first laser beam B1, i.e., when the region B2b located behind the sweep direction SD of the beam B2 is not irradiated, the second portion 14a2 is not formed, and the first portion 14a1 extends deeply from the surface Wa in the opposite direction to the Z direction. That is, in this embodiment, the second portion 14a2 is formed near the surface Wa by irradiating the region B2b located behind the sweep direction SD of the beam B2, so that it can be presumed that the first portion 14a1 is formed on the opposite side of the second portion 14a2 from the surface Wa, in other words, at a position away from the surface Wa in the opposite direction to the Z direction.

Figure 7 is a cross-sectional view showing a part of the welded portion 14. Figure 7 shows the boundaries of crystal grains obtained by the EBSD method. In addition, in Figure 7, as an example, crystal grains A having a crystal grain size of 13 [μm] or less are painted black. Note that 13 [μm] is not a threshold value of a physical property, but a threshold value set for the analysis of the experimental results. Also, from Figure 7, it is clear that crystal grains A are present in a relatively large amount in the first portion 14a1 and in a relatively small amount in the second portion 14a2. That is, the average value of the cross-sectional area of the crystal grains in the second portion 14a2 is larger than the average value of the cross-sectional area of the crystal grains in the first portion 14a1. The inventors confirmed through experimental analysis that the average value of the cross-sectional area of the crystal grains in the second portion 14a2 is 1.8 times or more the average value of the cross-sectional area of the crystal grains in the first portion 14a1.

As shown in region I in Figure 7, these relatively small crystal grains A are densely packed in a position away from the surface Wa in the Z direction, elongated in the Z direction. Furthermore, analysis of multiple locations at different positions in the X direction (sweeping direction SD) has confirmed that the region where crystal grains A are densely packed also extends in the sweeping direction SD. Because welding is performed while sweeping, it can be assumed that the crystals are formed in a similar shape in the sweeping direction SD.

In cases where it is difficult to distinguish the first portion 14a1 and the second portion 14a2 from the appearance or hardness distribution in the cross section, the first region Z1 and the second region Z2, which are geometrically determined from the position and width wb on the surface Wa of the weld metal 14a as shown in Figures 6 and 7, may be the first portion 14a1 and the second portion 14a2, respectively. As an example, the first region Z1 and the second region Z2 are rectangular regions extending in the Z direction with a width wm (equal width in the Y direction) in a cross section perpendicular to the sweep direction SD, the second region Z2 is a region from the surface Wa to a depth d in the Z direction, and the first region Z1 is a region deeper than the depth d, in other words, a region on the opposite side of the surface Wa with respect to the position of the depth d. The width wm can be, for example, 1/3 of the width wb (average bead width) on the surface Wa of the weld metal 14a, and the depth d (height, thickness) of the second region Z2 can be, for example, 1/2 of the width wb. The depth of the first region Z1 can be, for example, three times the depth d of the second region Z2. The inventors confirmed through experimental analysis of multiple samples that, with such settings of the first region Z1 and the second region Z2, the average cross-sectional area of the crystal grains in the second region Z2 is greater than the average cross-sectional area of the crystal grains in the first region Z1, and is at least 1.8 times that of the average cross-sectional area of the crystal grains in the first region Z1. This determination can also be evidence that the first portion 14a1 and the second portion 14a2 have been formed in the weld metal 14a by welding.

In addition, the inventors' experimental research has revealed that the aspect ratio of the weld metal 14a, i.e., the ratio of the depth dm to the width wb at the surface Wa of the weld metal 14a (dm/wb), is preferably 1 to 5, and more preferably 1.5 to 5, from the standpoint of ensuring weld strength and reducing the weld width.

As described above, in this embodiment, for example, laser light L emitted from laser devices 111, 112 (laser oscillators) including fiber lasers is irradiated from the outside of end portion 10a along the Z direction (opposite the Z direction) to weld adjacent end edges 11a, 12a in the Y direction (first direction). The wavelength of the laser light L is 380 nm or more and 1200 nm or less.

With this configuration and method, for example, it is easy to obtain a weld 14 with a relatively large weld depth relative to the weld width and the required weld strength. In addition, the entrapment of air into the molten metal during welding is suppressed, reducing weld defects.

In addition, in this embodiment, the laser light L includes, for example, a first laser light having a wavelength of 800 nm or more and 1200 nm or less, and a second laser light having a wavelength of 500 nm or less.

In this embodiment, for example, the wavelength of the second laser light is 400 nm or more and 500 nm or less.

This configuration and method makes it easier to obtain a higher quality weld 14 with fewer welding defects, such as spatter and blowholes.

In addition, in this embodiment, for example, if a gap is provided at the boundary Br between the edges 11a and 12a, the second laser light is irradiated across the gap on the surface Wa.

With this configuration and method, for example, the second laser light, which has a relatively high absorption rate in metal materials, generates a thermal conduction type melting region at the edges 11a, 12a on both sides of the gap, so that the gap can be filled more reliably with the welded portion 14, and thus it is easier to obtain a welded portion 14 with higher joining strength.

In addition, in this embodiment, for example, on the surface Wa, at least a portion of the beam B2 of the second laser light (second spot) is located forward of the beam B1 of the first laser light (first spot) in the sweep direction SD.

In addition, in this embodiment, for example, beam B1 and beam B2 at least partially overlap on surface Wa.

Furthermore, in this embodiment, for example, on the surface Wa, beam B2 is wider than beam B1.

Furthermore, in this embodiment, for example, on the surface Wa, the outer edge B2a (second outer edge) of the beam B2 surrounds the outer edge B1a (first outer edge) of the beam B1.

As described above, the inventors have confirmed that welding defects can be reduced in welding by irradiation of the laser light L that forms such beams B1 and B2 on the surface Wa. This is presumably because, as described above, the workpiece W is preheated by the region B2f of the beam B2 before the arrival of the beam B1, and the molten pool of the workpiece W formed by the beam B2 and the beam B1 is more stabilized. Therefore, with the laser light L having such beams B1 and B2, for example, it is possible to perform welding with fewer welding defects and higher welding quality. In addition, with such settings of the beams B1 and B2, for example, it is possible to obtain the advantage that the power of the first laser light can be lowered. In addition, when the beams B1 and B2 are irradiated coaxially, it is also possible to obtain the advantage that the relative rotation between the optical head 120 and the workpiece W is not required.

In addition, in this embodiment, for example, the aspect ratio of the weld metal 14a is preferably 1 or more and 5 or less, and more preferably 1.5 or more and 5 or less.

With this configuration, for example, it is easier to obtain the required weld strength and the weld width can be prevented from becoming too large.

In addition, in this embodiment, for example, the workpiece is made of any one of a copper-based metal material, an aluminum-based metal material, a nickel-based metal material, an iron-based metal material, and a titanium-based metal material.

The effect of the welding method of this embodiment can be obtained when the workpiece is made of any of the above materials. Note that the metal material may or may not be conductive.

[Modification of holding mechanism]
FIG. 8 is a side view showing another example of the holding mechanism 150A. The holding mechanism 150A can be equipped in place of the holding mechanism 150 of the first embodiment. The holding mechanism 150A has a pressing member 151A, a base 154, and a support member 155. The two pressing members 151A are arranged to sandwich the stack 10 in the Y direction. The two support members 155 each support the pressing member 151A so as to be rotatable around a rotation axis Ax along the Y direction. The two support members 155 are also arranged on both sides of the stack 10 in the Y direction, and are each attached on the base 154 so that their positions in the Y direction can be changed. The two support members 155 are fixed to the base 154 so that a force is applied from the two pressing members 151 to the stack 10 from both sides in the Y direction, causing the first member 11 and the second member 12 to approach each other in the Y direction. That is, by adjusting the position of the support member 155 in the holding mechanism 150A, the stack 10 can be set in an appropriate position and posture with respect to the laser light L. In addition, by rotating the pressing member 151A and the stack 10 relative to the support member 155 about the rotation axis Ax, the laser light L can be swept over the surface Wa of the end portion 10a.

[Second embodiment]
9 is a schematic diagram of a laser welding apparatus 100A according to the second embodiment. In this embodiment, an optical head 120 has a DOE 125 between a collimator lens 121-1 and a mirror 123. Except for this point, the laser welding apparatus 100A has a similar configuration to the laser welding apparatus 100 according to the first embodiment.

The DOE 125 shapes the shape of the beam B1 of the first laser light (hereinafter referred to as the beam shape). As conceptually illustrated in FIG. 10, the DOE 125 has a configuration in which, for example, multiple diffraction gratings 125a with different periods are superimposed. The DOE 125 can shape the beam shape by bending the parallel light in a direction influenced by each diffraction grating 125a or by superimposing the light. The DOE 125 can also be called a beam shaper.

The optical head 120 may have a beam shaper provided after the collimator lens 121-2 to adjust the beam shape of the second laser light, and a beam shaper provided after the filter 124 to adjust the beam shapes of the first laser light and the second laser light. By appropriately adjusting the beam shape of the laser light L using the beam shaper, the occurrence of welding defects can be further suppressed.

In addition, in the configuration of FIG. 9, the DOE 125 can generate a beam with the same beam shape as the second laser light, which makes it possible to omit the laser device 112. In this case, too, it is possible to suppress the occurrence of spatter during welding.

[Third embodiment]
11 is a schematic diagram of a laser welding apparatus 100B according to the third embodiment. In this embodiment, the optical head 120 has a galvanometer scanner 126 between a filter 124 and a condenser lens 122. Except for this point, the laser welding apparatus 100B has a similar configuration to the laser welding apparatus 100 according to the first embodiment.

The galvano scanner 126 has two mirrors 126a and 126b, and is a device that can move the irradiation position of the laser light L and sweep the laser light L without moving the optical head 120 by controlling the angles of the two mirrors 126a and 126b. The angles of the mirrors 126a and 126b are each changed by, for example, a motor (not shown). With this configuration, a mechanism for relatively moving the optical head 120 and the workpiece is not required, which has the advantage of making it possible to miniaturize the device configuration, for example.

[Fourth embodiment]
12 is a schematic diagram of a laser welding apparatus 100C of the fourth embodiment. In this embodiment, the optical head 120 has a DOE 125 (beam shaper) between the collimator lens 121-2 and the filter 124. Except for this point, the laser welding apparatus 100C has a similar configuration to the laser welding apparatus 100B of the third embodiment. With this configuration, it is possible to obtain the same effect as in the third embodiment by having the galvano scanner 126, and the same effect as in the second embodiment by having the DOE 125 (beam shaper).

In this embodiment, the optical head 120 may also have a beam shaper provided after the collimator lens 121-1 to adjust the beam shape of the first laser light, and a beam shaper provided after the filter 124 to adjust the beam shapes of the first laser light and the second laser light.

[Fifth embodiment]
13 is a schematic diagram of a laser welding apparatus 100D according to a fifth embodiment. In this embodiment, the optical head 120 includes a first portion 120-1 for irradiating a first laser beam L1 and a second portion 120-2 for irradiating a second laser beam L2, each of which is formed by a separate body (housing). With this configuration, the same actions and effects as those of the above embodiment can be obtained.

Figures 14 and 15 show examples of beams B1 and B2 of laser light formed on the surface Wa by the laser welding device 100D. As shown in Figures 14 and 15, according to the laser welding device 100D, the relative positions of the beams B1 and B2 can be set arbitrarily by setting the relative positions and postures of the first portion 120-1 and the second portion 120-2. Research by the inventors has revealed that when at least a part of the beam B2 (second spot) is located forward of the beam B1 (first spot) in the sweep direction SD on the surface Wa as shown in Figures 14 and 15, and when the beams B1 and B2 are in contact with each other or at least partially overlap each other, the same effect as in the first embodiment due to the preheating effect of the beam B2 can be obtained. It has also been found that when at least a part of the beam B2 is located forward of the beam B1 in the sweep direction SD, the beams B1 and B2 may be spaced apart by a small distance. Note that Figures 14 and 15 are merely examples, and the arrangement of beams B1 and B2 obtained by laser welding device 100D and the size of each beam B1 and B2 are not limited to the examples in Figures 14 and 15.

Sixth Embodiment
FIG. 16 is a perspective view of a vapor chamber 10E of the sixth embodiment, and FIG. 17 is a cross-sectional view taken along line XVII-XVII of FIG. 16. As shown in FIG. 16, the vapor chamber 10E includes a flat rectangular plate-like first member 11 and a second member 12. The first member 11 and the second member 12 are made of a metal material having a relatively high thermal conductivity. The first member 11 and the second member 12 are overlapped in the Y direction. In the vapor chamber 10E, the edges 11a, 12a of the end portion 10a as the peripheral portion of the first member 11 and the second member 12 overlapping in the Y direction are welded all around by a weld portion 14. The vapor chamber 10E is an example of a product.

As shown in FIG. 17, a storage chamber 10b for a fluid medium F is provided between the first member 11 and the second member 12. The storage chamber 10b is formed, for example, by providing a bottomed recess in the second member 12 that opens toward the first member 11. The recess may also be referred to as an opening. The storage chamber 10b is an example of a space.

The vapor chamber 10E is provided across the high-temperature portion and the low-temperature portion. The high-temperature portion is a heat generating body such as a CPU (central processing unit), and the low-temperature portion is a heat dissipating body such as a heat sink. The fluid medium F changes from liquid to gas phase by receiving heat from the high-temperature portion, and changes from gas to liquid phase by dissipating heat to the low-temperature portion. The fluid medium F that has become gas in the region adjacent to the high-temperature portion in the storage chamber 10b moves in the gaseous state within the storage chamber 10b to the region adjacent to the low-temperature portion within the storage chamber 10b. The fluid medium F that has become liquid in the region adjacent to the low-temperature portion within the storage chamber 10b moves within the storage chamber 10b to the region adjacent to the high-temperature portion within the storage chamber 10b by capillary action. By transporting heat by the fluid medium F in this way, the vapor chamber 10E can function as a cooling mechanism for the high-temperature portion.

As shown in FIG. 17, the end edge 11a and the end edge 12a are joined by a weld 14. The weld 14 can be formed by the welding method and laser welding apparatus 100, 100A-100D shown in the above-mentioned embodiment and modified example. The weld 14 has a configuration similar to that of the weld 14 in the first embodiment. The end portions 10a as the peripheral portions of the first member 11 and the second member 12 are fully welded by the weld 14, thereby sealing the fluid medium F in the storage chamber 10b.

According to the present embodiment, the same effects as those of the above embodiment can be obtained. That is, according to the vapor chamber 10E of the present embodiment, for example, it is easy to obtain a weld 14 having a relatively large weld depth relative to the weld width and a higher weld strength, or a weld 14 of higher quality with fewer weld defects.

[Modification of the sixth embodiment]
Figures 18 to 22 show vapor chambers 10F to 10I of modified examples of the sixth embodiment. In a vapor chamber 10F of a first modified example shown in Figure 18, an edge 11a of a flange 11b of a first member 11 and an edge 12a of a second member 12 are welded by a weld 14. In this vapor chamber 10F, the end portions 10a as peripheral portions of the first member 11 and the second member 12 are also welded all around by the weld 14, thereby sealing the fluid medium F in the storage chamber 10b. In this modified example, the recess forming the storage chamber 10b is provided only in the first member 11.

In the vapor chamber 10G of the second modified example shown in FIG. 19, the edge 11a as the outer peripheral surface of the first member 11 and the edge 12a of the second member 12 are welded by a weld 14. In this vapor chamber 10G, the end portions 10a as the peripheral portions of the first member 11 and the second member 12 are also welded all around by the weld 14, thereby sealing the fluid medium F in the storage chamber 10b. In this modified example, the recess that forms the storage chamber 10b is provided only in the first member 11.

In the vapor chamber 10H of the third modified example shown in FIG. 20, the edge 11a as the outer peripheral surface of the first member 11 and the edge 12a as the outer peripheral surface of the second member 12 are welded by a weld 14. In this vapor chamber 10H, the end portions 10a as the peripheral portions of the first member 11 and the second member 12 are also welded all around by the weld 14, thereby sealing the fluid medium F in the storage chamber 10b. In this modified example, the recesses that form the storage chamber 10b are provided in both the first member 11 and the second member 12.

21 is an exploded perspective view of the vapor chamber 10I of the fourth modified example, and FIG. 22 is a cross-sectional view along the Y direction passing through the approximate center of the vapor chamber 10I. In this modified example, the third member 13 is interposed between the first member 11 and the second member 12. The third member 13 is a flat rectangular plate-shaped member made of a metal material with relatively high thermal conductivity. The third member 13 overlaps the first member 11 and the second member 12 in the Y direction. The third member 13 is provided with a plurality of slits 13b as through holes penetrating in the Y direction (stacking direction). Both sides of each slit 13b in the Y direction are blocked by the first member 11 and the second member 12, thereby forming a storage chamber 10b for the fluid medium F in the vapor chamber 10I. The through holes are an example of an opening. Note that a recess that does not open the third member 13 may be provided instead of the slits 13b, and there may be only one slit 13b (through hole).

In the vapor chamber 10I, the edges 11a, 13a of the end 10a serving as the periphery of the first member 11 and the third member 13 overlapping in the Y direction are welded all around by the weld 14. In addition, the edges 12a, 13a of the end 10a serving as the periphery of the second member 12 and the third member 13 overlapping in the Y direction are welded all around by the weld 14. The third member 13 is one of the multiple members. In the vapor chamber 10I of this modification, the fluid medium F is also sealed in the storage chamber 10b by the weld 14 being welded all around. The first to fourth modifications described above also provide the same effects as the sixth embodiment.

[Seventh embodiment]
23 is a schematic diagram of a laser welding apparatus 100J according to the fifth embodiment. The laser welding apparatus 100J according to the present embodiment is modified based on the laser welding apparatus 100A according to the second embodiment. The laser welding apparatus 100J includes a control unit 161, a camera 162, a driving mechanism 163, a mirror 164, and a filter 165 in addition to the components of the laser welding apparatus 100A.

The filter 165 is provided between the mirror 123 and the filter 124. The filter 165 transmits the first laser light from the mirror 123 toward the filter 124 and reflects light (e.g., visible light) from the surface Wa toward the mirror 164. The light reflected by the mirror 164 is input to the camera 162. With this configuration, the camera 162 can capture an image on the surface Wa. The image captured by the camera 162 includes, for example, an image of the boundary between the edges 11a and 12a and an image of the beam (spot) of the laser light L. That is, the image shows the deviation of the spot of the laser light L formed on the surface Wa from the position (predetermined position) of the boundary where the laser light L should be irradiated. Therefore, the image captured by the camera 162 can be said to be a detection result of the deviation of the spot formed on the surface Wa from the predetermined position, and the camera 162 can be said to be an example of a detection mechanism that detects the deviation. In addition, if the position of the spot in the angle of view of the captured image is fixed, the captured image does not need to include an image of the spot, and the control unit 161 can detect the deviation of the spot formed on the surface Wa from the predetermined position from the position of the image of the boundary between the edges 11a and 12a in the captured image.

The control unit 161 detects the deviation of the spot from the predetermined position from the image captured by the camera 162, and controls the drive mechanism 163 to correct the deviation. The drive mechanism 163 is an actuator that operates in response to a command (electrical signal) from the control unit 161, and can move the optical head 120 in a direction intersecting the Z direction, for example, the Y direction. The drive mechanism 163 can have, for example, a rotation mechanism such as a motor, a speed reduction mechanism that reduces the rotation output of the rotation mechanism, and a motion conversion mechanism that converts the rotation reduced by the speed reduction mechanism into a linear motion. At this time, the control unit 161 may perform feedback control that performs control until the deviation is within a predetermined threshold. The control unit 161 and the drive mechanism 163 are an example of a correction mechanism. With such a configuration, it is possible to reduce the positional deviation of the welded portion 14 from the predetermined position, and therefore it is possible to obtain the advantage of further increasing the welding strength of the welded portion 14.

When applied to laser welding devices 100B and 100C having a galvanometer scanner 126 as in the third and fourth embodiments, the control unit 161 may change the irradiation direction of the laser light L, and thus the position of the spot on the surface Wa, instead of changing the position of the optical head 120 by the drive mechanism 163. With such a configuration, the same action and effect can be obtained. In this case, the control unit 161 and the galvanometer scanner 126 are an example of a correction mechanism.

Although the above is an example of an embodiment of the present invention, the above embodiment is merely an example and is not intended to limit the scope of the invention. The above embodiment can be implemented in various other forms, and various omissions, substitutions, combinations, and modifications can be made without departing from the spirit of the invention. Furthermore, the specifications of each configuration, shape, etc. (structure, type, direction, model, size, length, width, thickness, height, number, arrangement, position, material, etc.) can be modified as appropriate.

For example, a vapor chamber is an example of a product, and products are not limited to vapor chambers.

In addition, when sweeping the laser light over the workpiece, the surface area of the molten pool may be adjusted by known methods such as wobbling, weaving, or output modulation.

The object to be processed may also be a metal with a thin layer of another metal on its surface, such as a plated metal sheet.

10...Laminate (product)
10E to 10I...Vapor chamber (product)
10a... end portion 10a1... end portion 10b... storage chamber (space)
11...First member 11a...Edge 11b...Flange 12...Second member 12a...Edge 13...Third member 13a...Edge 13b...Slit 14...Welded portion 14a...Weld metal 14a1...First portion 14a2...Second portion 14b...Heat-affected portion 100, 100A to 100D, 100J...Laser welding device (welding device)
111...laser device (first laser oscillator)
112...laser device (second laser oscillator)
120...Optical head 120-1...First part 120-2...Second part 121, 121-1, 121-2...Collimator lens 122...Condenser lens 123...Mirror 124...Filter 125...DOE (diffractive optical element)
125a...diffraction grating 126...galvano scanner (correction mechanism)
126a, 126b... mirror 130... optical fiber 150, 150A... holding mechanism 151, 151A... pressing members 152, 153... support member 154... base 155... support member 161... control unit (correction mechanism)
162...Camera (detection mechanism)
163... Driving mechanism (correction mechanism)
164...mirror 165...filter A...crystal grain Ax...rotation axis B1...beam (first spot)
B1a...Outer edge B2...Beam (second spot)
B2a...Outer edge B2b...Area B2f...Area Br...Border C...Center point D1...Spot diameter (outer diameter)
D2: Spot diameter (outer diameter)
d...depth dm...depth (of weld metal) F...fluid medium I...area L...laser light L1...first laser light L2...second laser light SD...sweeping direction W...processing object Wa...surface wb...width (on the surface of the weld metal) wm...width (of the first and second regions) X...direction (second direction)
Y...direction (first direction, stacking direction)
Z…direction (third direction)
Z1...First area (first part)
Z2...Second area (second part)

Claims (9)

A welding method for welding adjacent edges in a first direction, the method comprising: irradiating a laser beam from an outside of an end portion of a plurality of members overlapping in a first direction, the end portions extending in a second direction intersecting the first direction, with the laser beam being swept in the second direction to form a weld extending in the second direction, the method comprising:
the laser light includes a first laser light having a wavelength of 800 nm or more and 1200 nm or less, and a second laser light having a wavelength of 500 nm or less,
on a surface of the end portion extending in the first direction and the second direction, an entire area of a first spot formed by the first laser light overlaps with a second spot formed by the second laser light, and a second outer edge of the second spot surrounds the first outer edge of the first spot at a distance;
The welded portion is
a weld metal extending in a third direction intersecting the first direction and the second direction from a surface extending in the first direction and the second direction of an end portion including the edge adjacent to the first direction;
a heat-affected zone located around the weld metal;
having
the weld metal has a second portion in contact with the surface, which is formed by being cooled after being melted by heat conduction type due to the irradiation of the second laser light, and a first portion in contact with the surface, which is formed by being cooled after being melted by keyhole type due to the irradiation of the first laser light, which is located on the opposite side of the surface with respect to the second portion, extends in the third direction from a position in contact with the second portion, and is not exposed on the surface side ,
The welding method according to claim 1, wherein an aspect ratio of the depth of the weld metal in the third direction to the width of the weld metal in the first direction is 1.5 or more and 5 or less . The welding method according to claim 1, wherein the wavelength of the second laser light is 400 nm or more and 500 nm or less. The welding method according to claim 1 or 2, wherein the second laser light is irradiated so as to span the gap at the boundary between the edges adjacent in the first direction in the first direction. The welding method according to any one of claims 1 to 3, wherein each of the plurality of members is made of one of copper-based metal materials, aluminum-based metal materials, nickel-based metal materials, iron-based metal materials, and titanium-based metal materials. A laser device that outputs laser light;
an optical head that irradiates the laser light outputted from the laser device;
Equipped with
A welding device which welds adjacent edges in a first direction to each other by irradiating laser light from an outside of an end portion of a plurality of members overlapping in a first direction, the end portions extending in a second direction intersecting the first direction, along a third direction intersecting the first direction and the second direction, while sweeping the laser light in the second direction to form a weld extending in the second direction, the welding device comprising:
the laser light includes a first laser light having a wavelength of 800 nm or more and 1200 nm or less, and a second laser light having a wavelength of 500 nm or less,
on a surface of the end portion extending in the first direction and the second direction, an entire area of a first spot formed by the first laser light overlaps with a second spot formed by the second laser light, and a second outer edge of the second spot surrounds the first outer edge of the first spot at a distance;
The welded portion is
a weld metal extending in a third direction intersecting the first direction and the second direction from a surface extending in the first direction and the second direction of an end portion including the edge adjacent to the first direction;
a heat-affected zone located around the weld metal;
having
the weld metal has a second portion in contact with the surface, which is formed by being cooled after being melted by heat conduction type due to the irradiation of the second laser light, and a first portion in contact with the surface, which is formed by being cooled after being melted by keyhole type due to the irradiation of the first laser light, which is located on the opposite side of the surface with respect to the second portion, extends in the third direction from a position in contact with the second portion, and is not exposed on the surface side ,
The aspect ratio of the weld metal's depth in the third direction to its width in the first direction is 1.5 or more and 5 or less . The welding device according to claim 5, further comprising a beam shaper that splits the laser light into multiple beams. The welding device according to claim 5 or 6, further comprising a galvanometer scanner that changes the emission direction of the laser light so that the laser light moves in a sweeping direction along the second direction on a surface of the end portion that extends in the first direction and the second direction. The welding device according to any one of claims 5 to 7, which is provided with a rotation mechanism that rotates the end portion around a rotation axis along the first direction. a detection mechanism for detecting a deviation of a spot formed on the surface by the laser light from a predetermined position;
A correction mechanism for correcting the deviation;
The welding device according to any one of claims 5 to 8, comprising:

Images