Laser pressure welding method

Abstract

The invention relates to the technical field of laser welding methods, and provides a laser pressure welding method which comprises the steps that the edge of a first metal workpiece and the edge of a second metal workpiece are stacked or in butt joint, so that the edge of the first metal workpiece and the edge of the second metal workpiece form a V-shaped structure; a laser source and the attaching position of the V-shaped structure are oppositely arranged, so that a laser beam enters the attaching position of the V-shaped structure; and laser welding edge pressing is carried out on the edge of the attaching position of the V-shaped structure in the extending direction of stacking or butt joint of the first metal workpiece and the second metal workpiece. According to the laser pressure welding method, during welding, the laser beam can directly enter the welding area, light does not need to be reflected on the surface of the metal workpiece, attenuation of energy of the laser beam is avoided, and the energy utilization rate is increased; and meanwhile, the polarization state of the laser beam and the surface roughness of the metal workpiece are not required, and the universality of the laser pressure welding method is improved.

Description

Technical Field

[0001] The invention relates to the technical field of laser welding methods, and in particular to a laser pressure welding method. Background Art

[0002] Laser welding is a high-efficiency and precision welding technology that uses a high-energy-density laser beam as a heat source to heat and melt materials, thereby achieving permanent connection of materials. It has the advantages of high energy density, fast welding speed, small welding deformation, good flexibility, wide application range, and high degree of automation. It is widely used in aviation, aerospace, automobiles, ships, high-speed rail, metallurgy, petroleum, chemical industry, new energy, biomedicine and other fields.

[0003] Unlike traditional laser welding processes, laser pressure welding uses the reflection characteristics of the metal material surface to the laser. The laser beam is irradiated on the joint surface of the workpiece to be connected, and the laser is guided to the welding area by multiple reflections of the laser on the metal material surface. Due to the specific geometric shape of the welded joint, the laser energy is completely absorbed in the welding area, so that the extremely thin layer of metal on the surface of the workpiece is heated or melted, and then the material is connected under pressure. Laser pressure welding only heats and melts a small amount of metal on the surface of the material, which greatly improves the effective utilization rate of the laser energy and greatly increases the welding speed. The extremely fast welding speed will effectively inhibit the formation of intermetallic compounds. At the same time, only heating or slightly melting a thin layer of the metal surface can also effectively inhibit the growth of intermetallic compounds.

[0004] In laser pressure welding, the reflectivity of the laser in the V-shaped structure is determined by the reflective properties of the metal itself and the polarization state of the laser beam. When the laser is incident vertically, the reflectivity of the metal to the laser is usually very high. When the laser is not incident vertically, the polarization state and incident angle of the beam have a great influence on the reflectivity and absorptivity. For parallel polarized light, at the Brewster angle, the reflectivity can be reduced by 3 to 5 times for different materials. For vertically polarized light, as the laser incident angle increases, the reflectivity continues to increase. Therefore, in laser pressure welding, the laser beam must be vertically polarized light, or the material must be a highly reflective metal material, which is a necessary condition for existing laser pressure welding technology, which imposes certain constraints on the use of laser pressure welding. Summary of the invention

[0005] The invention provides a laser pressure welding method, which is used to solve the defects in the prior art that the laser beam must be vertically polarized light or the welding material must be a highly reflective material during laser pressure welding.

[0006] The present invention provides a laser pressure welding method, comprising: overlapping or butting an edge of a first metal workpiece with an edge of a second metal workpiece so that the edge of the first metal workpiece and the edge of the second metal workpiece form a V-shaped structure; arranging a laser source and a joint portion of the V-shaped structure relative to each other so that a laser beam is incident on the joint portion of the V-shaped structure; and performing laser welding and pressing on the joint portion of the V-shaped structure along an extending direction of the overlapping or butting portion 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 butting an edge of a first metal workpiece with an edge of a second metal workpiece so that the edge of the first metal workpiece and the edge of the second metal workpiece form a V-shaped structure includes: bending an 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 and the edge of the second metal workpiece are overlapped, 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 butting the edge of a first metal workpiece with the edge of a second metal workpiece so that the edge of the first metal workpiece and the edge of the second metal workpiece form a V-shaped structure includes: processing a first cutout on the edge of the first metal workpiece, processing a second cutout on the edge of the second metal workpiece, the second cutout and the first cutout being able to fit together when the second metal workpiece and the first metal workpiece are butted; butting 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 cut on the edge of the first metal workpiece includes: processing the edge of the first metal workpiece 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.

[0010] According to a laser pressure welding method provided by the present invention, the laser pressure welding method also includes: respectively arranging pressure devices on both sides of the overlapping part of the first metal workpiece and the second metal workpiece; when laser welding the V-shaped structure, controlling the pressure device to synchronously roll along the overlapping part of the first metal workpiece and the second metal workpiece to achieve pressing while welding.

[0011] According to a laser pressure welding method provided by the present invention, the laser pressure welding method also includes: setting a pressure device at the joint between the first metal workpiece and the second metal workpiece; when laser welding 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 pressing while welding.

[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 butting the edge of the first metal workpiece with the edge of the second metal workpiece so that the edge of the first metal workpiece and the edge of the second metal workpiece form a V-shaped structure, the laser pressure welding method further includes: setting the laser spot of the laser beam to 50 μm~200 μm and the power density to 5.0×10 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 butting the edge of the first metal workpiece with the edge of the second metal workpiece to form a V-shaped structure with the edge of the first metal workpiece, the laser pressure welding method also includes: setting the pressure when pressing the V-shaped structure to 40N-2000N.

[0015] A laser pressure welding method provided by the present invention further includes: before laser pressure welding, surface cleaning of an edge of the first metal workpiece and an edge of the second metal workpiece.

[0016] The laser pressure welding method provided by the present invention can directly incident the laser beam on the welding zone during welding, without the need for light reflection on the surface of the metal workpiece, thus avoiding the attenuation of the laser beam energy and improving the energy utilization rate; at the same time, there are no requirements for the polarization state of the laser beam and the surface roughness of the metal workpiece, thereby improving the versatility of the laser pressure welding method. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 It is a schematic diagram of the principle of laser pressure welding in the prior art.

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

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

[0021] Figure 4 yes Figure 3 An enlarged view of A is shown in FIG.

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

[0023] Reference numerals: 1. First metal workpiece; 2. Second metal workpiece; 3. Pressure device; 11. First cut; 21. Second cut; 10. First metal plate; 20. Second metal plate. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] Combine the following Figure 1-Figure 5 The laser pressure welding method of the present invention is described.

[0026] like Figure 1 As shown, in the prior art, when laser pressure welding is adopted, the first end of the first metal plate 10 and the first end of the second metal plate 20 are overlapped, a pressure device is arranged at the overlapped position, and the second end of the first metal plate 10 and the second end of the second metal plate 20 are arranged at an angle. The laser beam is irradiated on the surface of the first metal plate 10 and the second metal plate 20, and the laser is directed to the welding area by using the multiple emission of the laser on the surface of the metal material. The laser energy is completely absorbed in the welding area, so that the extremely thin layer of metal on the surface of the workpiece is heated or melted, and then the connection of the first metal plate 10 and the second metal plate 20 is achieved under the action of pressure. In the 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 need to be highly reflective materials so that the light is reflected to the welding area.

[0027] The embodiment of the present invention provides a new laser pressure welding method, which can realize welding the workpieces to be welded together without limiting the polarization state of the laser beam or the surface roughness of the workpieces to be welded.

[0028] like Figure 2 As shown, the laser pressure welding method provided by the embodiment of the present invention includes the following steps: step 100, overlapping or butting the edge of the first metal workpiece 1 with the edge of the second metal workpiece 2, so that the edge of the first metal workpiece 1 and the edge of the second metal workpiece 2 form a V-shaped structure; step 200, arranging the laser source and the bonding part of the V-shaped structure relative to each other, so that the laser beam is incident on the bonding part of the V-shaped structure; step 300, laser welding and pressing the bonding part of the V-shaped structure along the extension direction of the overlapping or butting of the first metal workpiece 1 and the second metal workpiece 2.

[0029] 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 overlapped or butted according to the parts to be connected. Regardless of whether the first metal workpiece 1 and the second metal workpiece 2 are overlapped or butted, the edge of the first metal workpiece 1 and the edge of the second metal workpiece 2 must form a V-shaped structure, and the joint of the V-shaped structure is the area to be welded. It should be noted that: in this embodiment, the joint of the V-shaped structure is the joint of the edge of the first metal workpiece 1 and the edge of the second metal workpiece 2. Optionally, the opening angle of the V-shaped structure is 45°-120°. The laser is arranged relative to the joint of the V-shaped structure so that the fine focused beam emitted by the laser is directly incident on the joint of the V-shaped structure, so that the metal on the surface of the edge of the first metal workpiece 1 and the edge of the second metal workpiece 2 is quickly melted, and then the molten part is pressed together to press the edge of the first metal workpiece 1 and the edge of the second metal workpiece 2. Afterwards, the V-shaped structure is melted and pressed together along the extending direction of the overlapping or butted first metal workpiece 1 and the second metal workpiece 2, and the operation is repeated until the edge of the first metal workpiece 1 and the edge of the second metal workpiece 2 are completely welded together.

[0030] In this embodiment, the laser beam emitted by the laser is passed through a focusing lens to obtain a finely focused beam, and the focus spot diameter of the finely focused beam is 50 μm to 200 μm and the power density is 5.0×10 6 W / cm 2 ~5.0×10 8 W / cm 2 After the finely focused light beam is incident on the welding area, the surface materials of the first metal workpiece 1 and the second metal workpiece 2 can be quickly heated and melted, and then the first metal workpiece 1 and the second metal workpiece 2 are pressed together by pressure.

[0031] In this embodiment, there is no requirement for the polarization state of the laser beam, and there is no requirement for the roughness of the surface of the first metal workpiece 1 and the second metal workpiece 2. It is not necessary to grind and polish the surface of the first metal workpiece 1 and the second metal workpiece 2 to a mirror surface so as to have a high reflectivity. 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.

[0032] In the laser pressure welding method provided by the embodiment of the present invention, during welding, the laser beam can be directly incident on the welding area, and there is no need for the light to be reflected on the surface of the metal workpiece, thereby avoiding the attenuation of the laser beam energy and improving the energy utilization rate; at the same time, there are no requirements for the polarization state of the laser beam and the surface roughness of the metal workpiece, thereby improving the versatility of the laser pressure welding method.

[0033] like Figure 3 and Figure 4 As shown, for the edge of the first metal workpiece 1 and the edge of the second metal workpiece 2 to be stacked and welded together, before welding, the edge of the first metal workpiece 1 can be bent, or the edge of the second metal workpiece 2 can be bent, or the edge of the first metal workpiece 1 and the edge of the second metal workpiece 2 can be bent, so that when the two are stacked, a V-shaped structure can be formed. In this embodiment, the bonding point of the V-shaped structure is a bonding line. During welding, the bonding line is welded point by point, and multiple points form a line, so that the edge of the first metal workpiece 1 and the edge of the second metal workpiece 2 are all welded together.

[0034] In this embodiment, when the edge of the first metal workpiece 1 is bent and the edge of the second metal workpiece 2 is a plane, when the molten part is pressed, the edge of the second metal workpiece 2 can be set on the platform, and a pressure device 3 is 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 part.

[0035] like Figure 3 As shown, when the edge of the first metal workpiece 1 and the edge of the second metal workpiece 2 are bent, pressure devices 3 can be respectively set on both sides of the overlapping part of the first metal workpiece 1 and the second metal workpiece 2. When laser welding is performed on the V-shaped structure, the pressure device 3 is controlled to roll synchronously along the overlapping part of the first metal workpiece 1 and the second metal workpiece 2 to achieve melting and pressing at the same time.

[0036] In the two embodiments described above, the laser moves synchronously with the pressure device 3 to achieve melting and pressing of the same point to ensure uniformity of welding.

[0037] like Figure 5As shown, in another embodiment of the present invention, for butt welding the edge of the first metal workpiece 1 and the edge of the second metal workpiece 2, before welding, a first cut 11 can be processed on the edge of the first metal workpiece 1, and a second cut 21 can be processed on the edge of the second metal workpiece 2, and the second cut 21 and the first cut 11 can fit together when the second metal workpiece 2 and the first metal workpiece 1 are butted. The first end of the second metal workpiece 2 is butted 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, the laser beam is incident on the fitting part of the first cut 11 and the second cut 21, and after the surface metal of the first cut 11 and the second cut 21 is melted, the melted part is pressed together to connect the first cut 11 and the second cut 21 together.

[0038] Further, in Figure 5 In the embodiment shown, the edge of the first metal workpiece 1 is processed with an inclined surface from bottom to top, so that the width of the upper surface of the first metal workpiece 1 is smaller than the width of the lower surface of the first metal workpiece 1, so as to form a first cutout 11. Correspondingly, the edge of the second metal workpiece 2 is processed with an inclined surface from top to bottom, so that the width of the upper surface of the second metal workpiece 2 is larger than the width of the lower surface of the second metal workpiece 2, so as to form a second cutout 21. In this embodiment, the second end of the second metal workpiece 2 is warped.

[0039] like Figure 5 As shown, in this embodiment, when pressing the melted part, a pressure device 3 can be set at the joint of the first metal workpiece 1 and the second metal workpiece 2. When laser welding is performed on the V-shaped structure, the pressure device 3 is controlled to roll along the joint of the first metal workpiece 1 and the second metal workpiece 2 to achieve melting and pressing at the same time.

[0040] In the above-described embodiment, the pressure device 3 may be a pressure roller, and the pressure of the pressure device 3 when pressing the V-shaped structure is 40N-2000N.

[0041] In the embodiment of the present invention, before laser pressure welding, it is necessary to clean the edge of the first metal workpiece 1 and the edge of the second metal workpiece 2 to remove surface oil stains. Optionally, the cleaning agent may be acetone.

[0042] During the welding process, in order to prevent the weld from oxidation, argon gas can be used as a shielding gas to act on the fine focus spot position, where the flow rate of the shielding gas is 22L / min.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions 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: Overlapping or butting an edge of the first metal workpiece with an edge of the second metal workpiece so that the edge of the first metal workpiece and the edge of the second metal workpiece form a V-shaped structure; The laser source is arranged opposite to the joint of the V-shaped structure so that the laser beam is incident on the joint of the V-shaped structure; Along the extending direction of the overlapping or butting of the first metal workpiece and the second metal workpiece, the joints of the V-shaped structure are pressed together while being laser welded.

2. The laser pressure welding method according to claim 1, characterized in that: The step of overlapping or butting the edge of the first metal workpiece with the edge of the second metal workpiece so that the edge of the first metal workpiece and the edge of the second metal workpiece form a V-shaped structure comprises: 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 and the edge of the second metal workpiece are overlapped, 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 butting the edge of the first metal workpiece with the edge of the second metal workpiece so that the edge of the first metal workpiece and the edge of the second metal workpiece form a V-shaped structure comprises: Processing a first cutout on the edge of the first metal workpiece and processing a second cutout on the edge of the second metal workpiece, wherein the second cutout and the first cutout can fit together when the second metal workpiece is butted against the first metal workpiece; The first end of the second metal workpiece is butted against 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 warped to form the V-shaped structure with the other one.

4. The laser pressure welding method according to claim 3, characterized in that: The step of machining a first cutout on the edge of the first metal workpiece comprises: The edge of the first metal workpiece is processed 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 also includes: Pressure devices are respectively arranged on both sides of the overlapping portion of the first metal workpiece and the second metal workpiece; When laser welding is performed on the V-shaped structure, the pressure device is controlled to roll synchronously along the overlapping portion of the first metal workpiece and the second metal workpiece to achieve welding and pressing at the same time.

6. The laser pressure welding method according to claim 3, characterized in that: The laser pressure welding method also includes: A pressure device is provided at a joint between the first metal workpiece and the second metal workpiece; When laser welding is performed on 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 welding and pressing at the same time.

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: Before the step of overlapping or butting the edge of the first metal workpiece with the edge of the second metal workpiece so that the edge of the first metal workpiece and the edge of the second metal workpiece form a V-shaped structure, the laser pressure welding method further includes: The laser spot of the laser beam was set to 50 μm~200 μm and the power density was set to 5.0×10 6 W / cm 2 ~5.0×10 8 W / cm 2 .

9. The laser pressure welding method according to claim 1, characterized in that: Before the step of overlapping or butting the edge of the first metal workpiece with the edge of the second metal workpiece so that the edge of the first metal workpiece and the edge of the second metal workpiece 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.

10. 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 surface cleaned.

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