Laser pressure welding method

Abstract

The application relates to the technical field of laser welding methods, and provides a laser pressure welding method, which comprises the following steps: superimposing or butting the edges of a first metal workpiece and the edges of a second metal workpiece, so that the edges of the first metal workpiece and the edges of the second metal workpiece form a V-shaped structure; arranging a laser source opposite the abutting position of the V-shaped structure, so that a laser beam is incident on the abutting position of the V-shaped structure; and performing laser welding edge pressing on the abutting position of the V-shaped structure along the extension direction of the superimposition or butt joint of the first metal workpiece and the second metal workpiece. The laser pressure welding method has the advantages that, during welding, the laser beam can be directly incident on the welding area, the light does not need to be reflected on the surface of the metal workpiece, the energy attenuation of the laser beam is avoided, the energy utilization rate is improved, the polarization state of the laser beam and the reflection performance of the metal workpiece are not required, and the universality of the laser pressure welding method is improved.

Description

Technical Field

[0001] This invention relates to the field of laser welding methods, and more particularly to a laser pressure welding method. Background Technology

[0002] Laser welding is a highly efficient and precise welding technology that uses a high-energy-density laser beam as a heat source to heat and melt materials, thereby achieving a permanent connection between them. It has advantages such as high energy density, fast welding speed, small welding deformation, good flexibility, wide applicability, and high degree of automation. It is widely used in aviation, aerospace, automotive, shipbuilding, high-speed rail, metallurgy, petroleum, chemical, new energy, and biomedical fields.

[0003] Unlike traditional laser welding, laser pressure welding utilizes the reflective properties of metal surfaces to laser light. The laser beam is directed to the welding zone by multiple reflections from the metal surface. Due to the specific geometry of the weld joint, the laser energy is completely absorbed in the welding zone, heating or melting an extremely thin layer of metal on the workpiece surface. Then, under pressure, the materials are joined. Laser pressure welding only heats and melts a small amount of surface metal, greatly improving the efficient utilization of laser energy and significantly increasing welding speed. The extremely high welding speed effectively inhibits the formation of intermetallic compounds. Simultaneously, heating or micro-melting only a thin layer of the metal surface also effectively inhibits the growth of intermetallic compounds.

[0004] In laser pressure welding, the reflectivity of the laser within a V-shaped structure is determined by the reflectivity of the metal itself and the polarization state of the laser beam. When the laser is incident perpendicularly, the metal's reflectivity is typically high. When the laser is not incident perpendicularly, the polarization state and the incident angle significantly affect the reflectivity and absorptivity. For parallel polarized light, at Brewster's angle, the reflectivity can decrease by 3 to 5 times depending on the material. However, for perpendicularly polarized light, the reflectivity increases with the increase of the laser's incident angle. Therefore, in laser pressure welding, the laser beam must be perpendicularly polarized, or the material must be a highly reflective metal—these are essential conditions for current laser pressure welding technology, which imposes certain constraints on its application. Summary of the Invention

[0005] This invention provides a laser pressure welding method to solve the defects in the prior art where the laser beam must be vertically polarized or the welding material must be a highly reflective material during laser pressure welding.

[0006] This invention provides a laser pressure welding method, comprising: overlapping or mating the edges of a first metal workpiece and a second metal workpiece to form a V-shaped structure; positioning a laser source opposite to the contact area of ​​the V-shaped structure so that a laser beam is incident on the contact area of ​​the V-shaped structure; and performing laser welding and pressing on the contact area of ​​the V-shaped structure along the extension direction of the overlapping or mating of the first metal workpiece and the second metal workpiece.

[0007] According to a laser pressure welding method provided by the present invention, the step of overlapping or mating the edge of a first metal workpiece with the edge of a second metal workpiece to form a V-shaped structure includes: bending the edge of at least one of the first metal workpiece and the second metal workpiece so that when the edge of the first metal workpiece is overlapped with the edge of the second metal workpiece, the edge of the first metal workpiece and the edge of the second metal workpiece form the V-shaped structure.

[0008] According to a laser pressure welding method provided by the present invention, the step of overlapping or abutting the edges of a first metal workpiece and a second metal workpiece to form a V-shaped structure includes: processing a first slit on the edge of the first metal workpiece, processing a second slit on the edge of the second metal workpiece, wherein the second slit and the first slit can fit together when the second metal workpiece and the first metal workpiece are abutted; abutting the first end of the second metal workpiece with the first end of the first metal workpiece, and warping the second end of one of the first metal workpiece and the second metal workpiece to form the V-shaped structure with the other.

[0009] According to a laser pressure welding method provided by the present invention, the step of processing a first slit on the edge of the first metal workpiece includes: processing an inclined surface on the edge of the first metal workpiece from bottom to top, so that the width of the upper surface of the first metal workpiece is smaller than the width of the lower surface of the first metal workpiece.

[0010] According to a laser pressure welding method provided by the present invention, the laser pressure welding method further includes: setting pressure devices on both sides of the overlapping area of ​​the first metal workpiece and the second metal workpiece respectively; when performing laser welding on the V-shaped structure, controlling the pressure devices to roll synchronously along the overlapping area of ​​the first metal workpiece and the second metal workpiece to achieve simultaneous welding and pressing.

[0011] According to a laser pressure welding method provided by the present invention, the laser pressure welding method further includes: setting a pressure device at the joint between the first metal workpiece and the second metal workpiece; when performing laser welding on the V-shaped structure, controlling the pressure device to roll along the joint between the first metal workpiece and the second metal workpiece to achieve simultaneous welding and pressing.

[0012] According to a laser pressure welding method provided by the present invention, the opening angle of the V-shaped structure is 45°-120°.

[0013] According to a laser pressure welding method provided by the present invention, before the step of overlapping or butt-joining the edges of a first metal workpiece and a second metal workpiece to form a V-shaped structure, the laser pressure welding method further includes: setting the laser beam spot size to 50 μm~200 μm and the power density to 5.0×10⁻⁶. 6 W / cm 2 ~5.0×10 8 W / cm 2 .

[0014] According to a laser pressure welding method provided by the present invention, before the step of overlapping or mating the edge of the first metal workpiece with the edge of the second metal workpiece to form a V-shaped structure, the laser pressure welding method further includes setting the pressure for pressing the V-shaped structure to be 40N-2000N.

[0015] According to a laser pressure welding method provided by the present invention, the method further includes: cleaning the edges of the first metal workpiece and the edges of the second metal workpiece before performing laser pressure welding.

[0016] The laser pressure welding method provided by this invention allows the laser beam to be directly incident on the welding area during welding, eliminating the need for light reflection on the surface of the metal workpiece. This avoids laser beam energy attenuation and improves energy utilization. At the same time, it does not require specific polarization state of the laser beam or reflectivity of the metal workpiece, thus enhancing the versatility of the laser pressure welding method. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the principle of laser pressure welding in existing technology.

[0019] Figure 2 This is a schematic diagram of the laser pressure welding principle provided by the present invention.

[0020] Figure 3 This is one of the schematic diagrams of the laser pressure welding method provided by the present invention.

[0021] Figure 4 yes Figure 3 The enlarged view of point A shown in the image.

[0022] Figure 5 This is the second schematic diagram of the laser pressure welding method provided by the present invention.

[0023] Figure label:

[0024] 1. First metal workpiece; 2. Second metal workpiece; 3. Pressure device; 11. First cut; 21. Second cut;

[0025] 10. First metal plate; 20. Second metal plate. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0027] The following is combined with Figures 1-5 The laser pressure welding method of the present invention is described.

[0028] like Figure 1 As shown, in the prior art, when using laser pressure welding, the first ends of the first metal plate 10 and the first ends of the second metal plate 20 are stacked, and a pressure device is set at the stacking point. The second ends of the first metal plate 10 and the second metal plate 20 are set at an angle. A laser beam irradiates the surfaces of the first metal plate 10 and the second metal plate 20. The laser is guided to the welding area by multiple reflections of the laser from the metal surface. The laser energy is completely absorbed in the welding area, heating or melting an extremely thin layer of metal on the workpiece surface. Then, under pressure, the first metal plate 10 and the second metal plate 20 are joined. In existing laser pressure welding, the incident laser beam must be vertically polarized light, or the first metal plate 10 and the second metal plate 20 must be highly reflective materials to reflect the light to the welding area.

[0029] This invention provides a novel laser pressure welding method that can weld workpieces together without requiring restrictions on the polarization state of the laser beam or whether the workpiece is a highly reflective material.

[0030] like Figure 2 As shown, the laser pressure welding method provided in this embodiment of the invention includes the following steps: Step 100, overlapping or mating the edge of the first metal workpiece 1 with the edge of the second metal workpiece 2 to form a V-shaped structure; Step 200, setting the laser source opposite to the contact area of ​​the V-shaped structure so that the laser beam is incident on the contact area of ​​the V-shaped structure; Step 300, performing laser welding and pressing on the contact area of ​​the V-shaped structure along the extension direction of the overlap or mating of the first metal workpiece 1 and the second metal workpiece 2.

[0031] Specifically, when welding the first metal workpiece 1 and the second metal workpiece 2 together, the first metal workpiece 1 and the second metal workpiece 2 are stacked or butt-jointed depending on the part to be connected. Regardless of whether the first metal workpiece 1 and the second metal workpiece 2 are stacked or butt-jointed, the edges of the first metal workpiece 1 and the edges of the second metal workpiece 2 must form a V-shaped structure. The contact area of ​​the V-shaped structure is the area to be welded. It should be noted that in this embodiment, the contact area of ​​the V-shaped structure is the contact area between the edges of the first metal workpiece 1 and the second metal workpiece 2. Optionally, the opening angle of the V-shaped structure is 45°-120°. The laser is positioned opposite the contact area of ​​the V-shaped structure so that the finely focused beam emitted by the laser directly enters the contact area of ​​the V-shaped structure, causing the surface metal of the edges of the first metal workpiece 1 and the second metal workpiece 2 to melt rapidly. Then, the melted area is pressed together to press the edges of the first metal workpiece 1 and the second metal workpiece 2 together. Then, along the extension direction of the overlapping or mating of the first metal workpiece 1 and the second metal workpiece 2, the joint of the V-shaped structure is melted and pressed together. This operation is repeated until the edges of the first metal workpiece 1 and the edges of the second metal workpiece 2 are completely welded together.

[0032] In this embodiment, the laser beam emitted by the laser is focused by a focusing lens to obtain a finely focused beam with a focused spot diameter of 50 μm to 200 μm and a power density of 5.0 × 10⁻⁶. 6 W / cm 2 ~5.0×10 8 W / cm 2 When the finely focused beam is incident on the welding area, it can rapidly heat and melt the surface materials of the first metal workpiece 1 and the second metal workpiece 2, and then use pressure to press the first metal workpiece 1 and the second metal workpiece 2 together.

[0033] In this embodiment, there are no requirements regarding the polarization state of the laser beam, nor are there any requirements regarding the reflectivity of the materials of the first metal workpiece 1 and the second metal workpiece 2. In this embodiment, the materials of the first metal workpiece 1 and the second metal workpiece 2 can be the same or different. The materials of the first metal workpiece 1 and the second metal workpiece 2 can be aluminum, copper, steel, cast steel, etc.

[0034] The laser pressure welding method provided in this invention allows the laser beam to be directly incident on the welding area during welding, eliminating the need for light reflection on the surface of the metal workpiece. This avoids laser beam energy attenuation and improves energy utilization. At the same time, it does not require specific polarization state of the laser beam or reflectivity of the metal workpiece, thus enhancing the versatility of the laser pressure welding method.

[0035] like Figure 3 and Figure 4 As shown, for the purpose of overlapping and welding the edges of the first metal workpiece 1 and the second metal workpiece 2 together, before welding, the edges of the first metal workpiece 1, or the second metal workpiece 2, or both, can be bent to form a V-shaped structure when they are overlapped. In this embodiment, the joint of the V-shaped structure is a joint line. During welding, this joint line is welded point by point, forming a line from multiple points, so that the edges of the first metal workpiece 1 and the second metal workpiece 2 are completely welded together.

[0036] In this embodiment, when the edge of the first metal workpiece 1 is bent and the edge of the second metal workpiece 2 is flat, when pressing the molten area, the edge of the second metal workpiece 2 can be placed on a platform, and a pressure device 3 can be set on one side of the edge of the first metal workpiece 1. The pressure device 3 rolls along the edge of the first metal workpiece 1 to press the molten area.

[0037] like Figure 3 As shown, when the edges of the first metal workpiece 1 and the second metal workpiece 2 are both bent, pressure devices 3 can be set on both sides of the overlapping area of ​​the first metal workpiece 1 and the second metal workpiece 2 respectively. When laser welding the V-shaped structure, the pressure devices 3 are controlled to roll synchronously along the overlapping area of ​​the first metal workpiece 1 and the second metal workpiece 2 to achieve melting and pressing at the same time.

[0038] In the two embodiments described above, the laser and the pressure device 3 move synchronously to melt and press the same point, thereby ensuring the uniformity of the welding.

[0039] like Figure 5As shown, in another embodiment of the present invention, for welding the edges of a first metal workpiece 1 and a second metal workpiece 2 together, before welding, a first slit 11 can be machined on the edge of the first metal workpiece 1, and a second slit 21 can be machined on the edge of the second metal workpiece 2. The second slit 21 and the first slit 11 can fit together when the second metal workpiece 2 and the first metal workpiece 1 are joined. The first end of the second metal workpiece 2 is joined with the first end of the first metal workpiece 1, and the second end of one of the second metal workpiece 2 and the first metal workpiece 1 is warped to form a V-shaped structure with the other. During welding, a laser beam is incident on the fitting area of ​​the first slit 11 and the second slit 21. After melting the surface metal of the first slit 11 and the second slit 21, the molten area is pressed together to connect the first slit 11 and the second slit 21 together.

[0040] Furthermore, in Figure 5 In the illustrated embodiment, the edge of the first metal workpiece 1 is machined with an upward bevel, making the width of the upper surface of the first metal workpiece 1 smaller than the width of the lower surface, thus forming a first slit 11. Correspondingly, the edge of the second metal workpiece 2 is machined with a downward bevel, making the width of the upper surface of the second metal workpiece 2 greater than the width of the lower surface, thus forming a second slit 21. In this embodiment, the second end of the second metal workpiece 2 is warped.

[0041] like Figure 5 As shown, in this embodiment, when pressing the molten area, a pressure device 3 can be set at the joint between the first metal workpiece 1 and the second metal workpiece 2. When laser welding the V-shaped structure, the pressure device 3 is controlled to roll along the joint between the first metal workpiece 1 and the second metal workpiece 2 to achieve simultaneous melting and pressing.

[0042] In the embodiments described above, the pressure device 3 can be a pressure roller, and the pressure of the pressure device 3 when pressing the V-shaped structure is 40N-2000N.

[0043] In an embodiment of the present invention, before laser pressure welding, the edges of the first metal workpiece 1 and the edges of the second metal workpiece 2 need to be cleaned to remove surface oil. Optionally, the cleaning agent can be acetone.

[0044] During the welding process, in order to prevent the weld from oxidizing, argon gas can be used as a protective gas to act on the finely focused spot position, wherein the flow rate of the protective gas is 22L / min.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A laser pressure welding method, characterized in that, include: The laser beam spot size was set to 50 μm~200 μm, and the power density was set to 5.0×10⁻⁶. 6 W / cm 2 ~5.0×10 8 W / cm 2 ; The edges of the first metal workpiece are overlapped or joined with the edges of the second metal workpiece to form a V-shaped structure. The laser source is positioned opposite to the contact area of ​​the V-shaped structure so that the laser beam is incident on the contact area of ​​the V-shaped structure, causing the surface metal of the edge of the first metal workpiece and the surface metal of the edge of the second metal workpiece to melt, and the melted area is pressed together. Along the extension direction of the overlap or docking of the first metal workpiece and the second metal workpiece, the joint of the V-shaped structure is laser welded and pressed together.

2. The laser pressure welding method according to claim 1, characterized in that, The step of overlapping or joining the edges of the first metal workpiece and the second metal workpiece to form a V-shaped structure includes: The edge of at least one of the first metal workpiece and the second metal workpiece is bent so that when the edge of the first metal workpiece is overlapped with the edge of the second metal workpiece, the edge of the first metal workpiece and the edge of the second metal workpiece form the V-shaped structure.

3. The laser pressure welding method according to claim 1, characterized in that, The step of overlapping or joining the edges of the first metal workpiece and the second metal workpiece to form a V-shaped structure includes: A first slit is machined on the edge of the first metal workpiece, and a second slit is machined on the edge of the second metal workpiece, wherein the second slit and the first slit can fit together when the second metal workpiece and the first metal workpiece are joined. The first end of the second metal workpiece is joined to the first end of the first metal workpiece, and the second end of one of the first metal workpiece and the second metal workpiece is bent to form the V-shaped structure with the other.

4. The laser pressure welding method according to claim 3, characterized in that, The step of machining a first slit at the edge of the first metal workpiece includes: The edge of the first metal workpiece is machined into an inclined surface from bottom to top, so that the width of the upper surface of the first metal workpiece is smaller than the width of the lower surface of the first metal workpiece.

5. The laser pressure welding method according to claim 2, characterized in that, The laser pressure welding method further includes: Pressure devices are respectively installed on both sides of the overlapping area of ​​the first metal workpiece and the second metal workpiece; When laser welding the V-shaped structure, the pressure device is controlled to roll synchronously along the overlapping area of ​​the first metal workpiece and the second metal workpiece to achieve simultaneous welding and pressing.

6. The laser pressure welding method according to claim 3, characterized in that, The laser pressure welding method further includes: A pressure device is provided at the joint between the first metal workpiece and the second metal workpiece; During laser welding of the V-shaped structure, the pressure device is controlled to roll along the joint between the first metal workpiece and the second metal workpiece to achieve simultaneous welding and pressing.

7. The laser pressure welding method according to claim 1, characterized in that, The opening angle of the V-shaped structure is 45°-120°.

8. The laser pressure welding method according to claim 1, characterized in that, Prior to the step of overlapping or butt-joining the edges of the first metal workpiece and the second metal workpiece to form a V-shaped structure, the laser pressure welding method further includes: The pressure for pressing the V-shaped structure is set to 40N-2000N.

9. The laser pressure welding method according to claim 1, characterized in that, Also includes: Before laser pressure welding, the edges of the first metal workpiece and the second metal workpiece are cleaned.

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