Friction stir welding device and method for external source assisted cooperative regulation and control

Abstract

The invention provides a friction stir welding device and method for external source assisted cooperative regulation and control, the friction stir welding device is characterized in that a stirring head is arranged at the lower end of the friction stir welding device, an angle-adjustable clamp is arranged on the side portion of the friction stir welding device, and a laser generator is installed on the angle-adjustable clamp; the composite metal protection plate and the ultrasonic vibration plate are arranged below the stirring head, and a first welded part and a second welded part are arranged between the composite metal protection plate and the ultrasonic vibration plate; the composite metal protection plate is arranged at a splicing seam of the first welded part and the second welded part; and during welding, light spots of the stirring head and the laser generator are aligned with the splicing seam of the first welded part and the second welded part. The problems that when the metal composite plate is welded through friction stir welding, the completeness of composite layer metal is poor, and the welding efficiency is low are solved, meanwhile, the connecting quality of composite plate welding seams is improved, and the application range of friction stir welding is widened.

Description

Technical Field

[0001] The invention belongs to the technical field of friction stir welding, and particularly relates to a friction stir welding device and method with external source assistance and collaborative regulation. Background Technique

[0002] The statements in this part only provide background technical information related to the present invention, and do not necessarily constitute prior art.

[0003] At present, the welding methods of laminated metal composite plates can be divided into electron beam welding and laser welding. Among them, electron beam welding will generate brittle intermetallic compounds, and the clad metal will also be diluted, seriously affecting the joint functionality. Laser welding has a higher efficiency, but usually due to the large difference in melting points between the base metal and the clad metal, and the differences in thermal expansion coefficients and thermal conductivities between the two will cause stress concentration at the joint, forming cracks inside the weld nugget. The above factors result in poor weldability of the composite plate. In addition, the recoil pressure of the metal vapor will cause keyholes at the bottom of the molten pool, and internal voids are very likely to appear. At the same time, the development of new processes is also ongoing.

[0004] Friction stir welding (FSW), as a new type of solid-phase welding technology, uses the frictional heat between the stirring head and the workpiece to be welded to achieve the connection between materials. It has the advantages of energy conservation, environmental protection, high automation, high-quality welds, and a wide range of applicable materials. However, the intense friction between the stirring head and the workpiece to be welded will cause the stirring head to be easily worn and need to be replaced regularly. Compared with traditional fusion welding, the processing efficiency of friction stir welding is low, and the welding difficulty for high-melting-point materials is large, severely restricting the application of friction stir welding. Summary of the Invention

[0005] Aiming at the above problems, the present invention provides a friction stir welding device and method with external source assistance and collaborative regulation. By placing a composite metal protection plate above the weld to be made of the metal laminated composite plate, directly applying ultrasonic energy to the lower surface of the metal laminated composite plate, and supplementing with a high-energy laser beam to preheat the plate, the problems of poor integrity of the clad metal and low welding efficiency in friction stir welding of metal laminated composite plates are effectively solved, and at the same time, the connection quality of the composite plate weld and the application range of friction stir welding are improved.

[0006] To achieve the above object, the present invention is realized by the following technical solutions:

[0007] In a first aspect, the present invention provides a friction stir welding device with external source assisted collaborative regulation, comprising: a friction stir welding device, a stirring head, an ultrasonic vibration plate, a laser generator, an adjustable angle fixture, and a composite metal protection plate; the stirring head is arranged at the lower end of the friction stir welding device, the adjustable angle fixture is arranged at the side of the friction stir welding device, and the laser generator is installed on the adjustable angle fixture; the composite metal protection plate and the ultrasonic vibration plate are arranged below the stirring head, and a first workpiece to be welded and a second workpiece to be welded are arranged between the composite metal protection plate and the ultrasonic vibration plate; both the first workpiece to be welded and the second workpiece to be welded are metal laminated composite plates;

[0008] The composite metal protection plate is arranged at the splicing seam of the first workpiece to be welded and the second workpiece to be welded, and during welding, the spots of the stirring head and the laser generator are both aligned with the splicing seam of the first workpiece to be welded and the second workpiece to be welded.

[0009] Furthermore, the ultrasonic vibration plate is connected to an ultrasonic generator through a high-frequency wire, and the ultrasonic generator can generate and control ultrasonic energy and supply it to the ultrasonic vibration plate through the high-frequency wire;

[0010] The ultrasonic vibration plate is made of high-purity piezoelectric ceramic material to improve the energy conversion efficiency.

[0011] Furthermore, the laser generator is a high-power and high-stability pulsed laser, and is also equipped with a beam focusing and collimation system for precisely focusing the laser beam on the position to be welded to ensure the efficient utilization of laser energy;

[0012] The laser generator is also connected to a cooling system to ensure the stable operation of the laser during long-term operation.

[0013] Furthermore, the stirring head is made of a special high-temperature resistant and wear-resistant alloy material; the shape of the stirring pin on the stirring head is a conical structure with spiral threads.

[0014] In a second aspect, the present invention also provides a welding method for a friction stir welding device with external source assisted collaborative regulation, comprising the following steps:

[0015] S1. The first workpiece to be welded, the second workpiece to be welded, and the composite metal protection plate are fixed on the upper surface of the ultrasonic vibration plate workbench;

[0016] S2. The laser generator is fixed on the friction stir welding device through the adjustable angle fixture, the laser generator is parallel to the welding direction, the adjustable angle fixture can realize an angle transformation of 30-60° between the laser generator and the horizontal plane, and during welding, the laser generator and the stirring head move synchronously;

[0017] S3. The ultrasonic generator is started. Both the first welded part and the second welded part are in close contact with the ultrasonic vibration plate. The ultrasonic energy is directly applied to the lower surfaces of the first welded part and the second welded part. The angle of the laser generator is adjusted, and the laser generator is started to apply a laser beam to the welding position. The rotation speed range of the stirring head is set to 400 - 1200 r / min, and the welding speed is 30 - 800 mm / min. The main shaft is started, and the stirring pin on the stirring head presses down and penetrates into the composite metal protection plate, the first welded part, and the second welded part. By changing the relative position of the stirring head and the workpiece, the welding of the first welded part and the second welded part is achieved.

[0018] Further, it also includes: for thick first welded parts and second welded parts, after completing the welding in S3, the first welded part and the second welded part are flipped, reinstalled on the workbench, and the ultrasonic generator, the laser generator, and the friction stir welding machine are started to weld the back surface.

[0019] Further, in the step of using a fixture to fix the first welded part, the second welded part, and the composite metal protection plate to be welded, the fixture used is a fixture that can fix without damaging the surface of the plate;

[0020] The adjustable - angle fixture can achieve precise angle adjustment and locking to ensure the stable angle of the laser generator during the welding process.

[0021] Further, in S3, before starting the machine tool main shaft, it is necessary to preheat the first welded part and the second welded part through the laser generator to soften the material and improve the welding quality of the composite plate.

[0022] Further, during the welding process of the stirring head, the precise transformation of the relative position between the stirring head and the first welded part and the second welded part is realized through the automated control system of the machine tool.

[0023] Further, when performing friction stir welding on the back surfaces of the first welded part and the second welded part, the angle of the laser generator, the rotation speed of the stirring head, and the welding speed are adaptively adjusted according to the thickness and material properties of the first welded part and the second welded part.

[0024] Compared with the prior art, the advantages and positive effects of the present invention are:

[0025] During the friction stir welding process of the present invention, through the ultrasonic vibration plate and the laser generator, ultrasonic vibration and laser preheating are supplemented, and the protection plate is used to ensure the integrity of the first welded part and the second welded part, which can effectively improve the welding quality of the metal composite plate.

[0026] In the present invention, ultrasonic energy is directly applied below the plates to be welded. By ultrasonic vibration, the flow stress of the material is reduced, promoting the plastic flow of the material. Supplementary high-energy laser is used to preheat the workpiece to be welded, soften the material, and improve the welding quality of the composite plate. The composite metal protection plate is fixed above the clad layer, which can protect the clad layer metal from being damaged by the severe stirring friction of the shoulder, thus maintaining its integrity and improving the comprehensive performance of the joint. At the same time, the combined action of ultrasonic energy and high-energy laser can effectively reduce the welding load, slow down the wear of the stirring head, and effectively improve the welding speed and efficiency. Compared with other welding methods, this device does not produce harmful substances during operation and does not require any filler materials, ensuring that the weld composition is consistent with the base metal. Moreover, the operation process is simplified, making it suitable for automated operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings forming a part of this specification are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0028] Figure 1 It is a schematic structural diagram of the friction stir welding device of the present invention.

[0029] In the figure: 1. Friction stir welding device; 2. Adjustable angle fixture; 3. Laser generator; 4. Composite metal protection plate; 5. First workpiece to be welded; 6. Ultrasonic vibration plate; 7. Second workpiece to be welded; 8. Stirring head; 9. Ultrasonic generator. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0031] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the present invention 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, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof;

[0032] The traditional friction stir welding process mainly uses the frictional heat between the stirring head and the workpiece to achieve the connection between plates, which can lead to easy wear of the stirring head and requires regular replacement. Compared with traditional fusion welding, the friction stir welding has low processing efficiency, high equipment cost, and great difficulty in welding high melting point materials, severely restricting the application of friction stir welding. The present invention aims to solve the problems of poor integrity of the clad metal and low welding efficiency in friction stir welding of metal composite plates, and at the same time improve the connection quality of the weld of the composite plate. The technical solutions will be elaborated in detail according to the accompanying drawings of the specification below.

[0033] Example 1

[0034] This embodiment provides a friction stir welding device with exogenous auxiliary collaborative regulation, as Figure 1 shown, including: a friction stir welding device 1, a stirring head 8, an ultrasonic vibration plate 6, a laser generator 3, an adjustable angle fixture 2, and a composite metal protection plate 4; the stirring head 8 is arranged at the lower end of the friction stir welding device 1, the adjustable angle fixture 2 is arranged at the side of the friction stir welding device 1, and the laser generator 3 is installed on the adjustable angle fixture 2 for preheating the workpiece to be welded. Through laser preheating, the workpiece to be welded can reach a suitable temperature before welding, soften the material, further promote the flow and fusion of the material, make the combination of the weld more compact, and improve the quality and reliability of the welded joint; the composite metal protection plate 4 and the ultrasonic vibration plate 6 are arranged below the stirring head 8. Specifically, the ultrasonic vibration plate 6 can refine the weld grains and make the weld structure more uniform and dense. By reducing the flow stress of the material, the material can plastically flow more fully under the action of the stirring head 8, reducing defects such as holes and cracks in the weld, and significantly improving the strength and toughness of the weld; a first workpiece to be welded 5 and a second workpiece to be welded 7 are arranged between the composite metal protection plate 4 and the ultrasonic vibration plate; the composite metal protection plate 4 is arranged at the splicing seam of the first workpiece to be welded 5 and the second workpiece to be welded 7. During welding, the stirring head 8 and the light spot of the laser generator 3 are both aligned with the splicing seam of the first workpiece to be welded 5 and the second workpiece to be welded 7.

[0035] Both the first workpiece to be welded 5 and the second workpiece to be welded 7 are metal laminated composite plates; for the size of the composite metal protection plate 4 being larger than the length and width of the splicing seam, it can completely cover the clad metal at the splicing seam during welding, and its edge is designed with a rounded transition to avoid scratching the surface of the workpiece to be welded during clamping and welding; the design of the composite protection plate effectively avoids the direct damage of the stirring head 8 to the clad metal, maintains the integrity and original performance of the clad metal, thereby improving the comprehensive performance of the joint. Especially for some application scenarios with high requirements for clad performance, such as corrosion resistance and wear resistance, it has important significance.

[0036] The combined use of an ultrasonic vibration plate and a laser generator 3 enables the combined action of ultrasonic energy and high-energy laser, reducing the deformation resistance of the material and significantly reducing the load borne by the stirring head 8 during the welding process. This not only helps to reduce the energy consumption of the friction stir welding device 1, but also slows down the wear rate of the stirring head 8, extends the service life of the stirring head 8, and reduces production costs. At the same time, due to the reduction of the welding load, the mechanical structure strength requirements for the welding equipment are relatively reduced, which is beneficial to the lightweight design and maintenance of the equipment.

[0037] The laser generator 3 can be equipped with a beam focusing and collimation system to accurately focus the laser beam on the welding position to ensure the efficient utilization of laser energy. The laser generator 3 is equipped with a cooling system, which can adopt a closed-loop water cooling cycle method to ensure the stable operation of the laser during long-term operation.

[0038] Furthermore, the ultrasonic vibration plate is connected to an ultrasonic generator 9 through a high-frequency wire. The ultrasonic generator 9 can generate and control ultrasonic energy and supply it to the ultrasonic vibration plate through the high-frequency wire. In the specific implementation process, the ultrasonic vibration plate is made of high-purity piezoelectric ceramic material, which has extremely high energy conversion efficiency. When it comes into contact with the workpiece to be welded, it can more evenly transfer ultrasonic energy to the lower surface of the workpiece to be welded, avoiding local overheating or damage caused by energy concentration. The edge of the ultrasonic vibration plate can also be wrapped with a flexible buffer material, which can not only ensure close fit with the workbench, but also reduce the reflection and loss of ultrasonic energy.

[0039] Furthermore, the friction stir welding device 1 is a one-dimensional friction stir welding equipment or a two-dimensional friction stir welding equipment.

[0040] Furthermore, the stirring head 8 is made of a special high-temperature and wear-resistant alloy material. The shape of the stirring pin is a conical structure with spiral grooves. This design can more effectively transfer heat to the workpiece to be welded when rotating and pressing down, while enhancing the stirring effect on the material and promoting the full mixing of the material. The shoulder surface at the connection between the stirring head 8 and the stirring pin is provided with evenly distributed heat dissipation grooves, which can quickly dissipate the heat generated by friction during the welding process, reduce the temperature of the stirring head 8, and extend its service life.

[0041] Embodiment 2

[0042] This embodiment also provides a welding method for a friction stir welding device 1 with external source assisted collaborative regulation, including the following steps:

[0043] S1. The first workpiece to be welded 5, the second workpiece to be welded 7 and the composite metal protection plate 4 are fixed on the upper surface of the ultrasonic vibration plate workbench;

[0044] S2. The laser generator 3 is fixed to the friction stir welding device 1 by an adjustable angle fixture 2. The laser generator 3 is parallel to the welding direction. The adjustable angle fixture 2 can achieve an angle transformation of the laser generator 3 at an angle of 30 - 60° with the horizontal plane. During the welding process, the laser generator 3 moves synchronously with the stirring head 8;

[0045] S3. The ultrasonic generator is started. Both the first workpiece to be welded 5 and the second workpiece to be welded 7 are in close contact with the ultrasonic vibration plate, and ultrasonic energy is directly applied to the lower surfaces of the first workpiece to be welded 5 and the second workpiece to be welded 7. The angle of the laser generator 3 is adjusted, and the laser generator 3 is started to apply a laser beam to the position to be welded. The rotation speed range of the stirring head 8 is set to 400 - 1200 r / min, and the welding speed is 30 - 800 mm / min; The main shaft is started, and the stirring head 8 is pressed down to penetrate the composite metal protection plate 4, the first workpiece to be welded 5, and the second workpiece to be welded 7. By changing the relative position of the stirring head 8 and the workpiece, the welding of the two metal laminated composite plates is achieved.

[0046] Further, it also includes: For thick first workpieces to be welded 5 and second workpieces to be welded 7, after the welding in S3 is completed, the first workpiece to be welded 5 and the second workpiece to be welded 7 are flipped, reinstalled on the workbench, and the ultrasonic generator, the laser generator 3, and the friction stir welding machine are started to weld the back surface; enabling the welding of workpieces to be welded with different thicknesses.

[0047] Further, in the step of using a fixture to fix the first workpiece to be welded 5, the second workpiece to be welded 7, and the composite metal protection plate 4, the fixture uses a fixture that can fix and does not damage the surface of the plate;

[0048] The adjustable angle fixture 2 can achieve precise angle adjustment and locking to ensure the stable angle of the laser generator 3 during the welding process.

[0049] Further, in S3, before starting the machine tool spindle, it is necessary to preheat the first workpiece to be welded 5 and the second workpiece to be welded 7 through the laser generator 3. Under the synergistic effect of ultrasonic vibration and laser preheating, the plastic deformation ability of the material is enhanced, and the welding speed is effectively increased. Compared with the traditional friction stir welding method, this device can complete the welding of the same length of weld in a shorter time, improving the production efficiency. For large-scale metal composite plate welding production, it can significantly shorten the production cycle and improve the market competitiveness of the enterprise.

[0050] Further, during the welding process of the stirring head 8, the precise transformation of the relative position with the first workpiece to be welded 5 and the second workpiece to be welded 7 is achieved through the automated control system of the machine tool.

[0051] Further, when performing friction stir welding on the backs of the relatively thick first workpiece to be welded 5 and the second workpiece to be welded 7, the angle of the laser generator 3, the rotation speed of the stirring head 8, and the welding speed are adaptively adjusted according to the thickness and material properties of the first workpiece to be welded 5 and the second workpiece to be welded 7.

[0052] The device and welding method of the present invention can protect the functionality of the clad layer and improve the integrity of the clad layer by placing a protection plate. Ultrasonic vibration significantly refines the weld microstructure and reduces the formation of intermetallic compounds. The laser can increase the welding speed, precisely control the heat input, improve the process flexibility, and reduce the occurrence of welding defects.

[0053] The device and welding method of the present invention are applicable to the welding of various metal composite plates, including metal composite plates with different material combinations and different thicknesses. Whether it is a non-ferrous metal or a ferrous metal composite plate, high-quality welding can be achieved by adjusting process parameters such as ultrasonic energy, laser parameters, the rotation speed of the stirring head 8, and the welding speed. Compared with the traditional friction stir welding method, the welding of a weld of the same length can be completed in a shorter time, greatly improving the production efficiency. For large-scale metal composite plate welding production, the production cycle can be significantly shortened, and the market competitiveness of the enterprise can be improved.

[0054] Although the specific implementation manners of the present invention are described above in conjunction with the accompanying drawings, it is not a limitation to the protection scope of the present invention. Those skilled in the art should understand that various modifications or deformations that can be made without creative efforts on the basis of the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A friction stir welding device with external auxiliary collaborative regulation, characterized in that Including: Friction stir welding device, stirring head, ultrasonic vibration plate, laser generator, adjustable angle fixture, composite metal protection plate; the stirring head is arranged at the lower end of the friction stir welding device, and the adjustable angle fixture is arranged at the side of the friction stir welding device, and the laser generator is installed on the adjustable angle fixture; the composite metal protection plate and the ultrasonic vibration plate are arranged below the stirring head, and the first workpiece to be welded and the second workpiece to be welded are arranged between the composite metal protection plate and the ultrasonic vibration plate; both the first workpiece to be welded and the second workpiece to be welded are metal laminated composite plates. The composite metal protection plate is arranged at the splicing seam of the first workpiece to be welded and the second workpiece to be welded, and during welding, the stirring head and the light spot of the laser generator are both aligned with the splicing seam of the first workpiece to be welded and the second workpiece to be welded.

2. The friction stir welding device with external source assisted collaborative regulation according to claim 1, characterized in that, The ultrasonic vibration plate is connected with an ultrasonic generator through a high-frequency wire, and the ultrasonic generator can generate and control ultrasonic energy and supply it to the ultrasonic vibration plate through the high-frequency wire. The ultrasonic vibration plate is made of high-purity piezoelectric ceramic material to improve the energy conversion efficiency.

3. The friction stir welding device with external source assisted collaborative regulation according to claim 1, wherein The laser generator is a high-power and high-stability pulsed laser, and is also equipped with a beam focusing and collimating system for accurately focusing the laser beam on the position to be welded to ensure the efficient utilization of laser energy. The laser generator is also connected with a cooling system to ensure the stable operation of the laser during long-term operation.

4. The friction stir welding device with external source assisted collaborative regulation according to claim 1, characterized in that, The stirring head is made of a special high-temperature and wear-resistant alloy material; the shape of the stirring pin on the stirring head is a conical structure with spiral grooves.

5. The welding method of a friction stir welding device with external auxiliary collaborative regulation according to any one of claims 1-4, characterized in that, Including the following steps: S1. The first workpiece to be welded, the second workpiece to be welded and the composite metal protection plate are fixed on the upper surface of the ultrasonic vibration plate workbench. S2. The laser generator is fixed on the friction stir welding device through the adjustable angle fixture, the laser generator is parallel to the welding direction, and the adjustable angle fixture can realize the angle transformation of the laser generator at an angle of 30-60° with the horizontal plane. During welding, the laser generator and the stirring head move synchronously. S3. The ultrasonic generator is started, the first workpiece to be welded and the second workpiece to be welded are both in close contact with the ultrasonic vibration plate, and ultrasonic energy is directly applied to the lower surfaces of the first workpiece to be welded and the second workpiece to be welded. The angle of the laser generator is adjusted, the laser generator is started, and the laser beam is applied to the position to be welded. The rotation speed range of the stirring head is set to 400-1200 r / min, and the welding speed is 30-800 mm / min; the main shaft is started, and the stirring pin on the stirring head presses down and penetrates into the composite metal protection plate, the first workpiece to be welded and the second workpiece to be welded. By changing the relative position of the stirring head and the workpiece, the welding of the first workpiece to be welded and the second workpiece to be welded is realized.

6. The welding method of a friction stir welding device with external auxiliary collaborative regulation according to claim 5, characterized in that, Also including: For thick first workpieces to be welded and second workpieces to be welded, after completing the welding in S3, the first workpiece to be welded and the second workpiece to be welded are turned over, reinstalled on the workbench, and the ultrasonic generator, the laser generator and the friction stir welding machine are started to weld the back surface.

7. The welding method of a friction stir welding device with external auxiliary collaborative regulation as claimed in claim 5, wherein In the step of using the fixture to fix the first workpiece to be welded, the second workpiece to be welded and the composite metal protection plate, the fixture is a fixture that can fix and does not damage the surface of the plate. The adjustable angle fixture can achieve precise angle adjustment and locking to ensure the stable angle of the laser generator during the welding process.

8. The welding method of a friction stir welding device with external source assisted co-regulation as claimed in claim 5, wherein, In S3, before starting the machine tool spindle, it is necessary to preheat the first workpiece to be welded and the second workpiece to be welded through the laser generator to soften the material and improve the welding quality of the composite plate.

9. The welding method of a friction stir welding device with external source assisted collaborative regulation as claimed in claim 5, wherein, During the welding process, the relative positions of the stirring head and the first workpiece to be welded and the second workpiece to be welded are precisely changed through the automatic control system of the machine tool.

10. The welding method of a friction stir welding device with external source assisted collaborative regulation according to claim 6, characterized in that, When performing friction stir welding on the back of the first workpiece to be welded and the second workpiece to be welded, the angle of the laser generator, the rotation speed of the stirring head, and the welding speed are adaptively adjusted according to the thickness and material characteristics of the first workpiece to be welded and the second workpiece to be welded.

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