Thick plate material laser welding system and method

Abstract

The invention discloses a thick plate material laser welding system and method. The system comprises a first base material, a second base material, a laser device and a feeding mechanism, wherein the laser device is provided with an expansion lens, and the focal length of the expansion lens is reduced along with temperature rise. And an included angle a capable of being adjusted in the welding process is formed between the output light beam of the laser and the vertical line of the welding seam. The expansion lens is arranged to enable the focal plane subjected to welding machining to continuously rise, and the included angle a is set and is reduced in the machining process to enable the focal plane to gradually move downwards, so that an auxiliary welding material is located within the limited out-of-focus difference of the focal plane machined by the laser in each layer of welding; the machining effect of each welding machining is basically consistent, so that the welding seam has high uniformity at each depth, the compactness and precision of the whole laser welding machining are guaranteed, and then the connection strength between the first base metal and the second base metal is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of laser welding, and in particular relates to a thick plate material laser welding system and method. Background Art

[0002] With the development of modern industry, the application of high-load-bearing thick plate welding is becoming more and more common. Usually, a feeding mechanism is used to spray powder or fill wire to fill in additional auxiliary materials for welding. Powder spraying or wire filling welding method is an efficient and high-quality welding technology for thick plate material welding. Compared with the technology that does not add additional auxiliary materials for welding, it can weld all the narrow gaps in the entire depth direction between the parent materials. However, the current thick plate welding method, due to the large depth direction of the weld, usually requires a multi-layer and multi-pass welding method, and multiple auxiliary material filling welding. For high-strength thick plates, due to the inconsistent welding effect of the laser on each layer of powder or wire, the weld has defects such as uneven structure and unfused stratification between two adjacent passes. In addition, air is prone to appear in the middle of the weld, and eventually crystallization cracks are formed, that is, the welding effect is still not ideal. Summary of the invention

[0003] The main purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art and to provide a system and method for laser welding of thick plate materials. An expansion lens is set to continuously raise the focal plane of the welding process, and the focal plane is gradually moved downward by setting the laser inclination angle and reducing the inclination angle during the processing, so that the auxiliary welding material is within the limited defocus difference of the focal plane of the laser processing in each layer of welding, so that the weld has higher uniformity at all depths.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions: In one aspect of the present invention, a thick plate material laser welding system is provided, comprising a first base material, a second base material, a weld located at the connection between the first base material and the second base material, a laser, and a feeding mechanism; The laser is provided with an expansion lens whose focal length decreases as the temperature rises; The feeding mechanism is used to fill the auxiliary welding material into the weld; the laser is used to provide an output beam to weld the auxiliary welding material at the weld; There is a movable angle between the output beam of the laser and the vertical line of the weld. a .

[0005] As a preferred technical solution, it also includes a welding platform for supporting the first parent material and the second parent material, the angle a The size of the angle is adjusted by the laser or welding platform rotation, and the adjustment range is 5°~10°.

[0006] As a preferred technical solution, the feeding mechanism is provided with several feeding mechanisms, and the auxiliary welding material is filled by coaxial feeding or paraxial feeding; when paraxial feeding is performed, a certain angle is set between the output beam of the laser and the feeding head of the feeding mechanism. b , angle b The adjustment range is 5°~50°.

[0007] As a preferred technical solution, the expansion coefficient of the expansion lens is: within the range of 0-200 degrees Celsius, 0.8 * 10 -6 / K ~ 20*10 -6 / K.

[0008] As a preferred technical solution, the expansion lens is made of one of SCHOTT's N-BK7, N-BK10, N-FK5, N-FK58, N-FK51A, N-PK51 and N-SK2.

[0009] Another aspect of the present invention further provides a method for laser welding of thick plate materials, comprising the following steps: A laser configured with an expansion lens whose focal length decreases as temperature increases; The focus of the laser is adjusted to the starting position of the weld where the first base material and the second base material are connected, and a certain angle is set between the output beam of the laser and the vertical line of the weld. a ; The feeding mechanism is turned on to fill the auxiliary welding material into the weld at a certain rate, and the laser is turned on to move the focus of the laser relatively along the weld to weld the auxiliary welding material. a Gradually decrease until single-layer welding is completed; the angle a The speed of reduction is determined by the expansion coefficient of the expansion lens and the relative moving speed of the laser focus along the weld. Reset the angle a , the focal position of the laser and the feeding position, and weld layer by layer in sequence.

[0010] As a preferred technical solution, the feeding mechanism is provided with several feeding mechanisms, and the auxiliary welding material is filled by coaxial feeding or paraxial feeding; when paraxial feeding is performed, a certain angle is set between the output beam of the laser and the feeding head of the feeding mechanism. b , angle b The adjustment range is 5°~50°.

[0011] As a preferred technical solution, the angle is adjusted by rotating the laser or rotating the welding platform carrying the first base material and the second base material. a gradually decrease; angle a The adjustment range is 5°~10°.

[0012] As a preferred technical solution, the expansion coefficient of the expansion lens is: within the range of 0-200 degrees Celsius, 0.8 * 10 -6 / K ~ 20*10 -6 / K.

[0013] As a preferred technical solution, the expansion lens is made of one of SCHOTT's N-BK7, N-BK10, N-FK5, N-FK58, N-FK51A, N-PK51 and N-SK2.

[0014] Compared with the prior art, the present invention has the following advantages and beneficial effects: (1) The present invention sets an expansion lens to continuously raise the focal plane of the welding process, sets the laser inclination angle and reduces the inclination angle during the processing to gradually move the focal plane downward, so that the auxiliary welding material is within a limited defocus difference of the focal plane of the laser processing in each layer of welding, and the processing effect between each welding process is basically the same, so that the weld has high uniformity at all depths, ensuring the density and accuracy of the overall laser welding process, thereby improving the connection strength between the first parent material and the second parent material.

[0015] (2) The expansion lens of the laser in the present invention is in a state of continuous expansion, so that the focal plane of the laser welding process is in a state of continuous rise, and during the rotation of the laser, the focal plane can continue to move downward, forming a counteracting effect.

[0016] (3) The present invention controls the laser to weld from one end of the weld to the other end, and only by rotating the laser, the angle between the laser output beam and the vertical line of the weld is small. a Gradual changes do not require the laser to move vertically up and down, making it easier to control the laser to act exactly on the focal plane where the filled auxiliary welding material is located, making the welding process more stable and precise. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of a thick plate material laser welding system according to an embodiment of the present invention; Figure 2 is a diagrammatic illustration of the relative positions of a laser and a weld during processing of a single-layer weld according to an embodiment of the present invention; Figure 3 is a diagrammatic illustration of the relative position of the laser and the weld during the next layer weld processing of an embodiment of the present invention; Description of Figure Numbers: 1. First base material; 2. Second base material; 3. Welding seam; 4. Laser; 41. Expansion lens; 5. Feeding mechanism; 6. Welding platform. DETAILED DESCRIPTION

[0018] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present application.

[0019] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0020] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0021] Embodiment 1: like Figure 1 As shown, this embodiment provides a thick plate material laser welding system, including a first base material 1, a second base material 2, a weld 3, a laser 4, a feeding mechanism 5, and a welding platform 6.

[0022] The first parent material 1 and the second parent material 2 are arranged on a welding platform 6 .

[0023] The laser 4 is provided with an expansion lens 41 whose focal length decreases as the temperature rises.

[0024] The feeding mechanism 5 is used to fill the auxiliary welding material into the weld 3 between the first parent material 1 and the second parent material 2, and perform welding processing using the laser 4.

[0025] There is a certain angle between the output beam of the laser 4 and the vertical line of the weld 3. a , and can adjust the angle during welding a size.

[0026] In one or more preferred embodiments, the thickness of the plates of the first parent material 1 and the second parent material 2 is 10 mm-200 mm.

[0027] In one or more preferred embodiments, the weld 3 is in the shape of a straight strip. If the gap between the first base material 1 and the second base material 2 is not in the shape of a straight strip, S Shapes or other curved shapes can also be welded using the thick plate material laser welding system of this embodiment.

[0028] In one or more preferred embodiments, the laser 4 operates in a continuous or quasi-continuous laser mode, with a wavelength of 1000-1100nm infrared laser or 500-550nm green laser, and a power greater than 500W; when using 500-550nm green laser for welding, the spot size is 5um-1mm (suitable for narrow seam welding).

[0029] In one or more preferred embodiments, the expansion lens 41 is made of glass materials such as SCHOTT's N-BK7, N-BK10, N-FK5, N-FK58, N-FK51A, N-PK51 and N-SK2. The expansion coefficient of the expansion lens 41 is 0.8*10 -6 / K~ 20*10 -6 / K.

[0030] In one or more preferred embodiments, the laser 4 or the welding platform 6 can be rotated to adjust the angle a Size, angle a The adjustment range is 5° to 10°. The welding platform 6 has a large load-bearing capacity, and the rotating welding platform 6 needs to consume more energy.

[0031] In one or more preferred embodiments, the scanning speed of laser processing is 5 to 50 mm / s, which is achieved by parallel moving the laser 4 or parallel moving the welding platform 6. The difference is that the welding platform 6 has a large load-bearing weight, and moving the welding platform 6 requires more energy.

[0032] In one or more preferred embodiments, the feeding mechanism 5 is provided as one (or two or more), and the auxiliary welding material is filled by coaxial feeding (consistent with the light emitting direction of the laser processing) or paraxial feeding (not consistent with the light emitting direction of the laser processing); when the paraxial feeding is implemented, a certain angle is set between the output beam of the laser 4 and the feeding head of the feeding mechanism 5. b , angle b The adjustment range is 5°~50°.

[0033] In one or more preferred embodiments, the feeding mechanism 5 performs auxiliary welding material filling by powder spraying or wire filling, and the thickness of a single layer of auxiliary material is 30um to 2mm. When filling by powder spraying, the diameter of a single powder sprayed is 5um to 500um, and the powder feeding rate is 1 to 30g / min.

[0034] In one or more preferred embodiments, a container filled with protective gas is further provided, the container is provided with a nozzle, the protective gas is an inert gas, and the flow rate is 3 to 50 L / min.

[0035] Embodiment 2: This embodiment provides a thick plate material laser welding method, which can be applied to a thick plate material laser welding system of the above embodiment, including the following steps: Step 1: Configure a laser 4 including an expansion lens 41 whose focal length decreases as the temperature increases.

[0036] Step 2: Adjust the focus of the laser 4 to the starting position of the weld 3 at the connection between the first base material 1 and the second base material 2.

[0037] Step 3, start the feeding mechanism 5 to fill the auxiliary welding material into the weld 3 at a certain rate, and start the laser 4, so that the focus of the laser 4 moves relatively along the weld 3 (generally moves relatively along the horizontal plane) to weld the auxiliary welding material.

[0038] In particular, such as Figure 2 As shown, when the laser 4 is performing welding, the temperature of the expansion lens 41 is constantly rising and in a state of continuous expansion, that is, the focal plane of the laser 4 during welding is in a state of continuous rising. In order to keep the focal plane of the laser 4 consistent during the entire process of single-layer welding of the auxiliary welding material, when the laser 4 is welding from one end of the weld 3 to the other end, at the starting position, a certain angle is set between the output beam of the laser 4 and the vertical line of the weld 3. a At this time, the laser 4 just acts on the focal plane where the filled auxiliary welding material is located. As the welding process proceeds, the laser 4 is rotated so that the angle between the output beam of the laser 4 and the vertical line of the weld 3 is a Gradually decrease until the angle of the laser 4 reaches the other end of the weld 3 a is 0, that is, the direction of the output beam of the laser 4 coincides with the vertical direction of the weld 3. a The speed of reduction is determined by the expansion coefficient of the expansion lens 41, the relative moving speed of the focus of the laser 4 along the weld 3, and the angle a The speed of decrease is proportional to the expansion coefficient of the expansion lens 41 and inversely proportional to the relative movement speed of the focus of the laser 4 along the weld 3.

[0039] Since the expansion lens 41 of the laser 4 is in a continuous expansion state, the focal plane of the welding process of the laser 4 is in a continuous rising state, and during the rotation of the laser 4, the focal plane can be continuously moved downward to form a counteracting effect.

[0040] Step 4: After single-layer welding is completed, reset the angle a , the focal position of the laser 4 and the feeding position of the feeding mechanism 5.

[0041] like Figure 3 As shown, after processing a layer of weld 3, the angle is reset a , so that the focal plane position of the laser 4 acting on the weld 3 rises, and then the feeding mechanism 5 fills a layer of auxiliary welding material on the layer above the processed auxiliary material. At this time, the focal plane position of the laser 4 acting on the weld 3 will be adapted to the processing position of the newly filled auxiliary welding material, so that the auxiliary welding material is always within the limited defocus difference of the focal plane processed by the laser 4, ensuring that the processing effect of each layer of welding processing is basically consistent, achieving a high overall uniformity of the weld 3 at all depths, ensuring the density and accuracy of the overall laser welding processing, and thereby improving the connection strength between the first parent material 1 and the second parent material 2.

[0042] Step 5: Repeat steps 3 to 4 to weld layer by layer.

[0043] In one or more preferred embodiments, the laser 4 operates in a continuous or quasi-continuous laser mode, with a wavelength of 1000-1100nm infrared laser or 500-550nm green laser, and a power greater than 500W; when using 500-550nm green laser for welding, the spot size is 5um-1mm (suitable for narrow seam welding).

[0044] In one or more preferred embodiments, the expansion lens 41 is made of glass materials such as SCHOTT's N-BK7, N-BK10, N-FK5, N-FK58, N-FK51A, N-PK51 and N-SK2. The expansion coefficient of the expansion lens 41 is 0.8*10 -6 / K~ 20*10 -6 / K.

[0045] In one or more preferred embodiments, the weld 3 is in the shape of a straight strip. In other embodiments, if the gap between the base materials is not in the shape of a straight strip, S Shapes or other curved shapes can also be welded using the thick plate material laser welding method of this embodiment.

[0046] In one or more preferred embodiments, the thickness of the plates of the first parent material 1 and the second parent material 2 is 10 mm-200 mm.

[0047] In one or more preferred embodiments, the feeding mechanism 5 is provided as one (or two or more), and the auxiliary welding material is filled by coaxial feeding (consistent with the light emitting direction of the laser processing) or paraxial feeding (not consistent with the light emitting direction of the laser processing); when the paraxial feeding is implemented, a certain angle is set between the output beam of the laser 4 and the feeding head of the feeding mechanism 5. b , angle b The adjustment range is 5°~50°.

[0048] In one or more preferred embodiments, the feeding mechanism 5 performs auxiliary welding material filling by powder spraying or wire filling, and the thickness of a single layer of auxiliary material is 30um to 2mm. When filling by powder spraying, the diameter of a single powder sprayed is 5um to 500um, and the powder feeding rate is 1 to 30g / min.

[0049] In one or more preferred embodiments, the scanning speed of laser processing is 5 to 50 mm / s, which is achieved by parallel moving the laser 4 or parallel moving the welding platform 6. The difference is that the welding platform 6 has a large load-bearing weight, and moving the welding platform 6 requires more energy.

[0050] In one or more preferred embodiments, the angle a The adjustment range is 5°~10°.

[0051] In one or more preferred embodiments, step S3 is to rotate the welding platform 6 to adjust the angle a The difference is that the welding platform 6 has a large bearing weight, and the rotating welding platform 6 needs to consume more energy.

[0052] In one or more preferred embodiments, a container filled with protective gas is further provided, the container is provided with a nozzle, the protective gas is an inert gas, and the flow rate is 3 to 50 L / min.

[0053] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A thick plate material laser welding system, characterized in that: It comprises a first parent material (1), a second parent material (2), a welding seam (3) located at the connection between the first parent material (1) and the second parent material (2), a laser (4), and a feeding mechanism (5); The laser (4) is provided with an expansion lens (41) whose focal length decreases as the temperature rises; The feeding mechanism (5) is used to fill the auxiliary welding material into the weld (3); the laser (4) is used to provide an output light beam to weld the auxiliary welding material at the weld (3); An active angle is provided between the output beam of the laser (4) and the vertical line of the weld (3) a .

2. A thick plate material laser welding system according to claim 1, characterized in that: It also includes a welding platform (6) for supporting the first parent material (1) and the second parent material (2), wherein the angle a The size of is adjusted by the rotation of the laser (4) or the welding platform (6), and the adjustment range is 5° to 10°.

3. A thick plate material laser welding system according to claim 1, characterized in that: The feeding mechanism (5) is provided with a plurality of feeding mechanisms, and the auxiliary welding material is filled by coaxial feeding or side-axis feeding. When side-axis feeding is performed, a certain angle is provided between the output beam of the laser (4) and the feeding head of the feeding mechanism (5). b , angle b The adjustment range is 5°~50°.

4. A thick plate material laser welding system according to claim 1, characterized in that: The expansion coefficient of the expansion lens (41) is: 0.8*10 -6 / K ~ 20*10 -6 / K.

5. A thick plate material laser welding system according to claim 4, characterized in that: The expansion lens (41) is made of a material selected from the group consisting of SCHOTT's N-BK7, N-BK10, N-FK5, N-FK58, N-FK51A, N-PK51 and N-SK2.

6. A method for laser welding of thick plate materials, characterized in that: The following steps are involved: A laser (4) is provided having an expansion lens (41) whose focal length decreases as the temperature increases; The focus of the laser (4) is adjusted to the starting position of the weld (3) at the connection between the first parent material (1) and the second parent material (2), and a certain angle is set between the output beam of the laser (4) and the vertical line of the weld (3). a ; The feeding mechanism (5) is turned on to fill the welding seam (3) with auxiliary welding material at a certain rate, and the laser (4) is turned on to move the focus of the laser (4) relatively along the welding seam (3) to weld the auxiliary welding material, while making the angle a Gradually decrease until the single layer welding is completed; the angle a The speed of reduction is determined by the expansion coefficient of the expansion lens (41) and the relative moving speed of the focus of the laser (4) along the weld (3); Reset the angle a , the focal position of the laser (4) and the feeding position, and welding is performed layer by layer in sequence.

7. A thick plate material laser welding method according to claim 6, characterized in that: The feeding mechanism (5) is provided with a plurality of feeding mechanisms, and the auxiliary welding material is filled by coaxial feeding or side-axis feeding. When side-axis feeding is performed, a certain angle is provided between the output beam of the laser (4) and the feeding head of the feeding mechanism (5). b , angle b The adjustment range is 5°~50°.

8. The thick plate material laser welding method according to claim 6, characterized in that: The angle is adjusted by rotating the laser (4) or rotating the welding platform (6) carrying the first parent material (1) and the second parent material (2). a gradually decrease; angle a The adjustment range is 5°~10°.

9. A thick plate material laser welding method according to claim 6, characterized in that: The expansion coefficient of the expansion lens (41) is: 0.8*10 -6 / K ~ 20*10 -6 / K.

10. A thick plate material laser welding method according to claim 9, characterized in that: The expansion lens (41) is made of a material selected from the group consisting of SCHOTT's N-BK7, N-BK10, N-FK5, N-FK58, N-FK51A, N-PK51 and N-SK2.

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