Swing laser and electromagnetic field stirring composite follow-up welding device and method

Abstract

The invention discloses a swing laser and electromagnetic field stirring composite follow-up welding device and method, and belongs to the technical field of laser welding equipment. The device comprises a laser welding head, a driving device, an electric field generating device, a magnetic field generating device, a base and a water cooling loop. The laser welding head enables laser to act on a welding material to form a molten pool under the control of the driving device, and the electric field and magnetic field device acts on the molten pool. Wherein the electric field device comprises an electric brush with a specific structure and is made of a lightweight material; the magnetic field device forms a magnetic field through coil electrification. According to the welding method, welding materials are fixed to the base, laser is controlled to form a molten pool, and meanwhile an electric field and a magnetic field are changed to improve weld performance. When the purposes of stirring the molten pool and refining crystal grains are achieved, two electric field and magnetic field working modes exist, so that the molten pool is subjected to alternating Lorentz force; in order to improve the weld offset, the direction of the Lorentz force is changed by rotating the electric field device.

Description

Technical Field

[0001] The invention relates to the technical field of laser welding equipment, and in particular to a follow-up welding device and method combining swing laser and electromagnetic field stirring. Background Art

[0002] Existing laser welding systems are prone to defects such as pores, undercuts, and cracks when welding workpieces. Among them, laser swing welding improves welding quality by optimizing the laser welding path. This method stirs the front end of the molten pool evenly, greatly reducing pore defects. However, this stirring cannot effectively act on the solidification process at the rear end of the molten pool, resulting in the formation of a large number of columnar crystals at the weld, and the defects such as component segregation and cracks that exist therein have not been improved; in addition, the changing welding path causes the temperature gradient on the left and right sides of the molten pool to no longer change symmetrically, and the melting amount of the parent material on both sides is different, resulting in the phenomenon of weld offset, which affects the mechanical properties of the weld. Summary of the invention

[0003] The purpose of the present invention is to provide a follow-up welding device and method of a composite of oscillating laser and electromagnetic field stirring, which utilizes the advantage of laser oscillating welding that can fully stir the molten pool to reduce porosity defects, and on this basis adds specific electric fields and magnetic fields. The interaction between the two can make the metal liquid in the molten pool be subjected to the Lorentz force in a specific direction, thereby improving the defects that may occur in laser oscillating welding when processing different materials.

[0004] To achieve the above-mentioned purpose, the present invention provides a follow-up welding device that combines oscillating laser and electromagnetic field stirring, including a laser welding head, a driving device, an electric field generating device, a magnetic field generating device and a base, wherein: under the control of the driving device, the laser welding head can make the laser act on the joint of the welding material fixed on the base along a specific path and form a molten pool; the electric field generating device and the magnetic field generating device can act on the molten pool.

[0005] Preferably, the electric field generating device comprises a brush power supply interface and an elastic brush, the elastic brush is interconnected with a spring, the elastic brush is covered with a layer of insulating medium, and the elastic brush is made of beryllium copper or one or more elastic materials in a multi-layer composite.

[0006] Preferably, the magnetic field generating device is provided with a coil power-on interface and a coil, and the coil is powered on by passing an excitation current into the coil power-on interface to form a magnetic field around the molten pool.

[0007] Preferably, the electric field generating device is made of one or more lightweight materials such as aluminum alloy or carbon fiber.

[0008] Preferably, the bottom of the driving device is also equipped with a water inlet and outlet of a water cooling circuit to reduce the heat generated by the energized coil.

[0009] A servo welding method combining oscillating laser and electromagnetic field stirring comprises the following steps: fixing the welding material on a base, controlling the laser welding head by a driving device so that the laser acts on the joint of the welding material along a specific path to form a molten pool; and simultaneously changing the electric field and magnetic field acting on the molten pool to improve the weld performance.

[0010] Preferably, when the working purpose is to stir the entire molten pool and refine the grains: an excitation current is passed through the coil power-on interface of the magnetic field generating device to energize the coil to form a magnetic field, and the magnetic field can change direction regularly under the action of the frequency converter; an excitation current is passed through the brush power-on interface of the electric field generating device, and the current flows through the elastic brush to form a loop with the metal liquid in the molten pool to generate an electric field, and the electric field can also change direction regularly under the action of the frequency converter, and there are two working modes: Mode 1: The current passed into the electric field generating device is an alternating current, generating an electric field with changing direction; the current passed into the magnetic field generating device is a direct current, generating a magnetic field with constant direction; Mode 2: The current passed into the electric field generating device is a direct current, which generates an electric field with a constant direction; the current passed into the magnetic field generating device is an alternating current, which generates a magnetic field with a changing direction; the current is controlled by a frequency converter so that the molten pool is subjected to a Lorentz force with an alternating direction.

[0011] Preferably, when the working purpose is to improve the defect of weld deviation: an excitation current is passed through the coil power-on interface of the magnetic field generating device to make the coil conductive and form a magnetic field, and an excitation current is passed through the brush power-on interface of the electric field generating device. The current flows through the elastic brush and the metal liquid in the molten pool to form a loop to generate an electric field; the current passed through the electric field generating device and the magnetic field generating device are both direct currents, which generate a Lorentz force with a constant direction; the direction of the electric field is changed by rotating the electric field generating device, thereby changing the direction of the Lorentz force acting on the molten pool.

[0012] Therefore, the present invention adopts a oscillating laser and electromagnetic field stirring composite follow-up welding device and method of the above structure, which has the following beneficial effects: The present invention can flexibly adjust the working state under different welding conditions. When the workpiece is thicker than 10mm, the defect of weld offset has little effect on the final performance of the weld. The electric field and magnetic field generated by the welding device can make the molten pool liquid subject to the Lorentz force of alternating direction, stirring the entire molten pool, thereby refining the grains and improving the weld performance. When welding workpieces, the defect of weld offset has a greater impact on the final performance of the weld. The electric field and magnetic field generated by the welding device can make the molten pool liquid subject to the Lorentz force with a constant direction, so that the metal liquid in the molten pool flows to the side with lower heat, improving the temperature distribution in the molten pool, thereby suppressing the weld offset defect. Apart from the above two working conditions, during the welding process, the actual welding effect of different weldments should be considered, and appropriate welding strategies should be adopted to give priority to improving defects such as pores, undercuts, cracks, etc. that greatly weaken the performance of the weld.

[0013] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of a servo welding device and method of the present invention that combines oscillating laser and electromagnetic field stirring; Figure 2 This is a schematic diagram of the electric field and magnetic field working mode of Example 1 of a servo welding device and method for combining oscillating laser and electromagnetic field stirring of the present invention; Figure 3 This is a schematic diagram of the electric field and magnetic field working mode of Example 2 of a servo welding device and method combining oscillating laser and electromagnetic field stirring of the present invention; Reference numerals 1. Magnetic field generating device, 2. Coil power-on interface, 3. Brush power-on interface, 4. Electric field generating device, 5. Driving device, 6. Water inlet and outlet of water cooling circuit, 7. Coil, 8. Laser welding head, 9. Molten pool, 10. Spring, 11. Insulating medium, 12. Elastic brush, 13. Welding material, 14 Base, 15. Weld, 16. Laser stirring path, 17. Front end of molten pool, 18. Lorentz force one, 19. Magnetic field, 20. Electric field one, 21. Rear end of molten pool, 22. Lorentz force two, 23. Electric field two, 24. Lorentz force three, 25. Actual weld, 26. Ideal weld, 27. Electric field three, 28. Central axis. DETAILED DESCRIPTION

[0015] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0016] Unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0017] Example like Figure 1 As shown, the present invention provides a follow-up welding device that combines oscillating laser and electromagnetic field stirring, including a laser welding head 8, a driving device 5, an electric field generating device 4, a magnetic field generating device 1 and a base 14, wherein: the laser welding head 8, under the control of the driving device 5, can make the laser act on the joint of the welding material 13 fixed on the base 14 along a specific path and form a molten pool 9; the electric field generating device 4 and the magnetic field generating device 1 can act on the molten pool 9.

[0018] The electric field generating device 4 comprises a brush power supply interface 3 and an elastic brush 12. The elastic brush 12 is connected to the spring 10. The elastic brush 12 is covered with a layer of insulating medium 11. The elastic brush 12 is made of beryllium copper or one or more elastic materials in a multi-layer composite.

[0019] The magnetic field generating device 1 is provided with a coil power supply interface 2 and a coil 7 . The coil 7 is powered by supplying an excitation current to the coil power supply interface 2 , thereby forming a magnetic field around the molten pool 9 .

[0020] The electric field generating device 4 is made of one or more lightweight materials such as aluminum alloy or carbon fiber.

[0021] The bottom of the driving device 5 is also provided with a water inlet and outlet 6 of a water cooling circuit for reducing the heat generated by the energized coil.

[0022] Specifically, the welding material 13 is fixed on the base 14, and the laser welding head 8, under the control of the driving device 5, causes the laser to act on the joint of the welding material 13 along a specific path, and forms a molten pool 9. At the same time, by changing the electric field and magnetic field 19 acting on the molten pool 9, the performance of the weld 15 is improved with different emphases.

[0023] When the working purpose is to stir the entire molten pool 9 and refine the grains, the working process of the electric field generating device 4 and the magnetic field generating device 1 is as follows: an excitation current is passed through the coil power-on interface 2 in the magnetic field generating device 1 to energize the coil 7 and form a magnetic field 19 around the molten pool 9. The magnetic field 19 can change direction regularly under the action of the frequency converter; and an excitation current is passed through the brush power-on interface 3 of the electric field generating device 4. The excitation current flows through the elastic brush 12 and forms a loop with the metal liquid in the molten pool 9 to generate an electric field. The electric field can change direction regularly under the action of the frequency converter. There are two ways to change the direction of the electric field in this device. One is to change the direction of the current passed into the brush power-on interface 3, and the other is to rotate the electric field generating device 4 to change the relative position of the electric field and the molten pool 9. The direction of the electric field described in this paragraph can be achieved by changing the direction of the current passed into the brush power interface 3. At this time, there are both a magnetic field 19 and an electric field in the molten pool 9, which is further divided into the following two working modes: ① The current passed into the electric field generating device 4 is an alternating current, which generates an electric field with changing direction; the current passed into the magnetic field generating device 1 is a direct current, which generates a magnetic field 19 with constant direction. ② The current passed into the electric field generating device 4 is a direct current, which generates an electric field with constant direction; the current passed into the magnetic field generating device 1 is an alternating current, which generates a magnetic field 19 with changing direction. Both working modes control the currents of the electric field generating device 4 and the magnetic field generating device 1 through the frequency converter, generating a Lorentz force with alternating direction acting on the molten pool 9.

[0024] When the purpose of the work is to improve the defect of weld deviation, the working process of the electric field generating device 4 and the magnetic field generating device 1 is as follows: an excitation current is passed through the coil power interface 2 in the magnetic field generating device 1 to make the coil 7 conductive and form a magnetic field 19 around the molten pool 9; an excitation current is passed through the brush power interface 3 of the electric field generating device 4, and the excitation current flows through the elastic brush 12 to form a loop with the metal liquid in the molten pool 9 to generate an electric field. At this time, the molten pool 9 has an electric field and a magnetic field 19, and the currents passed through the electric field generating device 4 and the magnetic field generating device 1 are both direct currents, generating a Lorentz force with a constant direction. The direction of the electric field is changed by rotating the electric field generating device 4, thereby changing the direction in which the Lorentz force acts on the molten pool 9.

[0025] Figure 1 The electric field generating device 4 is made of lightweight materials, such as aluminum alloy, carbon fiber, etc. At the same time, in order to prevent the outer shell of the electric field generating device 4 from being conductive, a layer of insulating medium 11 is covered on the elastic brush 12. The elastic brush 12 is made of elastic materials such as beryllium copper and multi-layer composite.

[0026] A follow-up welding method combining oscillating laser and electromagnetic field stirring comprises the following steps: fixing the welding material on a base, controlling the laser welding head by a driving device so that the laser acts on the joint of the welding material along a specific path to form a molten pool; and simultaneously changing the electric field and magnetic field 19 acting on the molten pool to improve the weld performance.

[0027] When the working purpose is to stir the entire molten pool 9 and refine the grains: an excitation current is passed through the coil power-on interface 2 of the magnetic field generating device 1 to energize the coil 7 to form a magnetic field 19, and the magnetic field 19 can change direction regularly under the action of the frequency converter; an excitation current is passed through the brush power-on interface 3 of the electric field generating device 4, and the current flows through the elastic brush 12 to form a loop with the metal liquid in the molten pool to generate an electric field, and the electric field can also change direction regularly under the action of the frequency converter, and there are two working modes: Mode 1: The current passed into the electric field generating device 4 is an alternating current, generating an electric field with changing direction; the current passed into the magnetic field generating device 1 is a direct current, generating a magnetic field 19 with constant direction; Mode 2: The current passed into the electric field generating device 4 is a direct current, which generates an electric field with a constant direction; the current passed into the magnetic field generating device 1 is an alternating current, which generates a magnetic field 19 with a changing direction; the current is controlled by a frequency converter so that the molten pool 9 is subjected to a Lorentz force with an alternating direction.

[0028] When the working purpose is to improve the defect of the offset of the weld 15: an excitation current is passed through the coil power-on interface 2 of the magnetic field generating device 1 to make the coil 7 conductive and form a magnetic field 19, and an excitation current is passed through the brush power-on interface 3 of the electric field generating device 4. The current flows through the elastic brush 12 and the metal liquid in the molten pool 9 to form a loop to generate an electric field; the current passed through the electric field generating device 4 and the magnetic field generating device 1 are both direct currents, which generate a Lorentz force with a constant direction; the direction of the electric field is changed by rotating the electric field generating device 4, thereby changing the direction of the Lorentz force acting on the molten pool 9.

[0029] Example 1 Figure 2 In the example shown, the laser stirring path 16 is a clockwise circle, the direction of the electric field is perpendicular to the weld 15, the coil power interface 2 in the magnetic field generating device 1 is fed with a current of constant direction, generating a magnetic field 19 of constant direction; the brush power interface 3 in the electric field generating device 4 is fed with a current of alternating direction, generating an electric field 1 20 and an electric field 2 23 of alternating direction, under the action of the electric field 1 20, the metal liquid in the molten pool is subjected to an upward Lorentz force 1 18; under the action of the electric field 2 23, the metal liquid in the molten pool 9 is subjected to a downward Lorentz force 2 22. From a certain moment in the welding process, the front end 17 of the molten pool has been stirred uniformly by the laser, and the alternating Lorentz force 1 18 and the Lorentz force 2 22 mainly act on the solidification process of the rear end 21 of the molten pool.

[0030] Example 2 Figure 3 In the example shown, due to the effect of surface tension, when the laser passes through the left side of the molten pool 9, it stirs the solidifying metal liquid at the rear end 21 of the molten pool to the front end 17 of the molten pool. This process absorbs the heat of the molten pool 9 and the laser energy, causing the left weld to shrink inwards; when the laser passes through the right side of the molten pool 9, it stirs the high-temperature metal liquid at the front end 17 of the molten pool to the rear end 21 of the molten pool. This process causes the right side of the molten pool 9 to gain more heat, causing the right weld to expand outwards. Figure 3 It can be seen that the weld 15 and the central axis 28 of the molten pool 9 are not on the same straight line, and the actual weld 25 formed will always be offset from the ideal weld 26, forming a weld offset defect.

[0031] The laser stirring path 16 is a clockwise circle, the direction of the electric field 3 27 is perpendicular to the weld 15, the coil power interface 2 in the magnetic field generating device 1 is fed with a current with a constant direction, generating a magnetic field 19 with a constant direction; the brush power interface 3 in the electric field generating device 4 is fed with a current with a constant direction, generating an electric field 3 27 with a constant direction. By rotating the electric field generating device 4 to change the direction of the Lorentz force 3 24, the metal liquid in the molten pool 9 flows to the side with lower heat, thereby improving the temperature distribution in the molten pool 9.

[0032] Therefore, the present invention adopts the above-mentioned oscillating laser and electromagnetic field stirring composite follow-up welding device and method to improve the temperature distribution in the molten pool, thereby suppressing the weld offset defect. In addition to the above two working conditions, during the welding process, the actual welding effect of different weldments should be considered, and appropriate welding strategies should be adopted to give priority to improving defects such as pores, undercuts, cracks, etc. that greatly weaken the weld performance.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A follow-up welding device combining oscillating laser and electromagnetic field stirring, characterized in that: It includes a laser welding head, a driving device, an electric field generating device, a magnetic field generating device and a base, wherein: under the control of the driving device, the laser welding head can make the laser act on the joint of the welding material fixed on the base along a specific path and form a molten pool; the electric field generating device and the magnetic field generating device can act on the molten pool.

2. The oscillating laser and electromagnetic field stirring combined follow-up welding device according to claim 1 is characterized in that: The electric field generating device comprises a brush power supply interface and an elastic brush, wherein the elastic brush is connected to a spring and is covered with a layer of insulating medium. The elastic brush is made of beryllium copper or one or more elastic materials in a multi-layer composite.

3. The oscillating laser and electromagnetic field stirring combined follow-up welding device according to claim 1 is characterized in that: The magnetic field generating device is provided with a coil power-on interface and a coil. The coil is powered by supplying an excitation current to the coil power-on interface to form a magnetic field around the molten pool.

4. The oscillating laser and electromagnetic field stirring combined follow-up welding device according to claim 1 is characterized in that: The electric field generating device is made of one or more lightweight materials such as aluminum alloy or carbon fiber.

5. The oscillating laser and electromagnetic field stirring combined follow-up welding device according to claim 1 is characterized in that: The bottom of the driving device is also equipped with a water inlet and outlet for a water cooling circuit to reduce the heat generated by the energized coil.

6. A servo welding method of a oscillating laser and electromagnetic field stirring composite, applied to a servo welding device of a oscillating laser and electromagnetic field stirring composite as claimed in claims 1 to 5, characterized in that: The method comprises the following steps: fixing the welding material on a base, controlling the laser welding head through a driving device, making the laser act on the joint of the welding material along a specific path to form a molten pool; and simultaneously changing the electric field and magnetic field acting on the molten pool to improve the weld performance.

7. The oscillating laser and electromagnetic field stirring combined follow-up welding method according to claim 6 is characterized in that: When the working purpose is to stir the entire molten pool and refine the grains: an excitation current is passed through the coil power-on interface of the magnetic field generating device to energize the coil to form a magnetic field. The magnetic field can change direction regularly under the action of the inverter; an excitation current is passed through the brush power-on interface of the electric field generating device. The current flows through the elastic brush and forms a loop with the metal liquid in the molten pool to generate an electric field. The electric field can also change direction regularly under the action of the inverter. There are two working modes: Mode 1: The current passed into the electric field generating device is an alternating current, which generates an electric field with changing direction; The current passed into the magnetic field generating device is a direct current, which generates a magnetic field with a constant direction; Mode 2: The current passed into the electric field generating device is a direct current, generating an electric field with a constant direction; The current passed into the magnetic field generating device is an alternating current, which generates a magnetic field with changing direction; the current is controlled by a frequency converter, so that the molten pool is subjected to the Lorentz force with alternating direction.

8. The servo welding method of combining oscillating laser and electromagnetic field stirring according to claim 6 is characterized in that: When the working purpose is to improve the defect of weld deviation: an excitation current is passed through the coil power-on interface of the magnetic field generating device to make the coil conductive and form a magnetic field, and an excitation current is passed through the brush power-on interface of the electric field generating device. The current flows through the elastic brush and forms a loop with the metal liquid in the molten pool to generate an electric field; The currents passed into the electric field generating device and the magnetic field generating device are both direct currents, which generate a Lorentz force with a constant direction; the direction of the electric field is changed by rotating the electric field generating device, thereby changing the direction in which the Lorentz force acts on the molten pool.

Images