Electromagnetic-assisted underwater laser material addition device and method

Abstract

The present invention relates to the field of laser processing technology, and in particular to an electromagnetic-assisted underwater laser additive device and method, the device comprising a laser additive component, an underwater dry zone component, a rotating electric field component, a rotating magnetic field component and an induction heating coil. The present invention arranges a rotating electric field and a rotating magnetic field inside and outside the underwater dry zone component respectively, and the electromagnetic field action area can change with the processing position. During the underwater additive manufacturing process, the molten pool is always at the center of the electromagnetic field action, and can stably apply electromagnetic stirring to the molten pool to improve / accelerate the flow of the molten pool. On the one hand, the flow improvement can facilitate the escape of bubbles and improve the density of the component. On the other hand, accelerating the flow of the molten pool can break up coarse dendrites, increase the nucleation points in the molten pool, and achieve the purpose of grain refinement. In this process, the element distribution between the dendrites will be more uniform. It has a good effect on the uniformity of the structure and defect control of the molded parts.

Description

Technical Field

[0001] The present invention relates to the technical field of laser processing, and in particular to an electromagnetic-assisted underwater laser material addition device and method. Background Art

[0002] Laser additive manufacturing technology, also known as 3D printing technology, is an integrated manufacturing technology that takes into account both molding accuracy and high performance requirements. It includes laser stereo forming technology with synchronous powder feeding as the main technical feature and selective laser melting technology with powder bed as the main technical feature. The structure of metal components manufactured by laser additive manufacturing is usually composed of columnar crystals that grow continuously epitaxially from the matrix. The grains are often very coarse, but the substructure within the crystal is fine, the structure is dense and there is no macro segregation, which makes the mechanical properties of laser additively manufactured metal components comparable to those of forgings. However, when the application environment places higher requirements on the mechanical properties of the material, the mechanical properties of laser additively manufactured parts cannot meet the use requirements for the time being. On the one hand, we can continue to improve the laser additive process to obtain a better match between the organization and mechanical properties, and on the other hand, we can use external fields to assist in improving the laser additive process.

[0003] At present, the methods of assisting laser additive manufacturing mainly include external field assistance such as ultrasound assistance, electromagnetic field assistance and high-frequency induction assistance. In the process of laser additive manufacturing, applying ultrasonic vibration or electromagnetic field is a method of controlling the solidification process by forcing fluid flow. The flow of liquid in the liquid phase will change the temperature field and concentration field at the front of the solidification interface, thereby affecting the solidification structure. The high-frequency vibration and radiation pressure of ultrasound can form effective stirring and flow in the molten metal in the molten pool, which can significantly reduce the surface tension and friction of the liquid, and can play a role in removing gas from the molten metal.

[0004] From offshore to offshore, the service environment faced by marine engineering equipment is becoming increasingly harsh. Once marine engineering equipment fails, it is urgently necessary to repair it to ensure the safety and service life of the equipment. Underwater local dry laser additive manufacturing technology provides technical conditions for the direct processing and repair of underwater structural parts. The underwater laser additive manufacturing process is carried out in a sealed underwater dry area component, and the layers are stacked according to the specified path to complete the repair of the damaged parts. In the process of underwater additive manufacturing, except for the area covered by the underwater dry area component, the other parts of the workpiece are directly in contact with water, which will produce a huge temperature gradient in the molten pool, further promoting the formation of coarse columnar crystals. At the same time, water cooling will accelerate the cooling of the molten pool, resulting in uneven solute distribution, which is not conducive to the escape of pores, burying hidden dangers for component cracking, and is not conducive to the mechanical properties of the repaired components, shortening the service life.

[0005] In the underwater laser additive process, the auxiliary electromagnetic field can generate additional Lorentz force inside the molten pool, which works together with the Marangoni force inside the molten pool to improve the flow of the molten pool and alleviate the above-mentioned problems. Chinese patent application CN113664335 A discloses an electromagnetic ultrasonic composite energy field device and its application method, which introduces ultrasonic vibration and electromagnetic stirring in the additive manufacturing process in the onshore environment, and uses the coordinated effect of the electromagnetic field and the ultrasonic vibration field to achieve the effects of breaking dendrites, refining the structure, stirring the molten pool, and removing gas, thereby improving the forming quality and mechanical properties of the formed parts. The scheme has a complex structure and cannot be directly applied to underwater operations, and it is difficult to meet the requirements of marine equipment for manufacturing equipment. Chinese patent application CN110802304 A discloses an electromagnetic-assisted arc additive manufacturing forming device and method. During onshore arc additive manufacturing, the weld pool is supported by electromagnetic induction force to prevent the weld from flowing, thereby reducing the residual stress of the weld joint and improving the mechanical properties of the parts. However, this method is also not suitable for adjusting the flow of the molten pool during underwater in-situ repair. Chinese patent CN 105522153 B discloses an electromagnetic field assisted laser additive manufacturing device, which buries a magnetic field generator under a substrate. Although it achieves the purpose of electromagnetic assisted laser processing, it is not suitable for the actual repair process. In addition, the device is not suitable for adjusting the flow of the molten pool during underwater in-situ repair. Summary of the invention

[0006] The purpose of the present invention is to address the problems existing in the background technology and propose an electromagnetic-assisted underwater laser additive device and method to regulate the structural uniformity and pore defects of underwater laser additive repair components to improve the repair quality.

[0007] The technical solution of the present invention is an electromagnetic-assisted underwater laser material-adding device, comprising a housing, a laser material-adding component, an underwater dry area component, a rotating magnetic field component, a rotating electric field component and an induction heating coil;

[0008] The housing includes a sealed pressure-resistant housing A and a sealed pressure-resistant housing B; the sealed pressure-resistant housing B includes an upper housing and a lower housing;

[0009] The laser additive component is installed inside the sealed pressure-resistant housing A, and the underwater dry area component is installed below the sealed pressure-resistant housing A; the upper end of the underwater dry area component is sealed and the lower end is open; the output end of the laser additive component is inserted into the underwater dry area component;

[0010] A first air inlet 3 and a second air inlet for communication are provided between the underwater dry area component and the sealed pressure-resistant housing A; compressed air is provided by an air compressor and injected into the underwater dry area component through the first air inlet and the second air inlet to form a local dry area;

[0011] The rotating electric field assembly and the induction heating coil are installed inside the underwater dry zone assembly;

[0012] The sealed pressure-resistant casing B is installed on the outside of the underwater dry zone component, and the rotating magnetic field component is installed in the sealed pressure-resistant casing B.

[0013] Preferably, the underwater dry area component is a soft magnet, and a gap of 1-2 mm is left between the underwater dry area component and the outer surface of the part to be repaired; the outer side and the inner side of the side wall of the underwater dry area component are respectively grooved.

[0014] Preferably, the rotating electric field assembly includes a waterproof and pressure-resistant motor A, a gear shaft, a gear bearing A, a charged metal plate positive electrode, and a charged metal plate negative electrode;

[0015] The waterproof and pressure-resistant motor A is fixed in the left groove at the top of the underwater dry zone component, the gear bearing A is fixed in the inner groove of the underwater dry zone component, the output end of the waterproof and pressure-resistant motor A is transmission-connected to the gear shaft, the gear end of the gear shaft is meshed with the gear bearing A, and the positive pole of the charged metal plate and the negative pole of the charged metal plate are respectively fixed on the left and right sides of the bottom of the gear bearing A.

[0016] Preferably, the waterproof and pressure-resistant motor A drives the gear shaft to rotate, forming a rotating electric field around the molten pool;

[0017] The action area of ​​the rotating electric field generated by the rotating electric field component changes with the processing position, and the molten pool is located at the center of the action range of the rotating electric field.

[0018] Preferably, the induction heating coil and the rotating electric field assembly do not interfere with each other.

[0019] Preferably, the rotating magnetic field assembly includes a waterproof and pressure-resistant motor B, a transmission shaft, a coupling, a driving gear, a gear bearing B, a permanent magnet N pole and a permanent magnet S pole;

[0020] The waterproof and pressure-resistant motor B is fixed to the left side of the sealed pressure-resistant housing A through a connecting rod; one end of the transmission shaft is connected to the waterproof and pressure-resistant motor B through a coupling, and the other end is connected to the driving gear, and the driving gear is meshed with the gear bearing B; the other end of the gear bearing B is fixed in the outer groove of the underwater dry area component, and the permanent magnet N pole and the permanent magnet S pole are fixed on the left and right sides of the bottom of the gear bearing B respectively.

[0021] Preferably, the waterproof and pressure-resistant motor B drives the driving gear to rotate, forming a rotating magnetic field around the molten pool;

[0022] The action area of ​​the rotating magnetic field generated by the rotating magnetic field assembly changes with the processing position, and the molten pool is located at the center of the action range of the rotating magnetic field.

[0023] Preferably, the upper shell and the lower shell of the sealed pressure-resistant shell B are both soft magnets; the sealed pressure-resistant shell B composed of the upper shell and the lower shell isolates the rotating magnetic field assembly from the water environment.

[0024] An electromagnetic-assisted underwater laser material addition method comprises the following specific steps:

[0025] S1. The electromagnetic-assisted underwater laser additive device is transported to the target waters by a ship and placed into the seawater. The engineering and technical personnel move the electromagnetic-assisted underwater laser additive device to the part of the workpiece to be repaired by controlling the cable; compressed air is injected into the underwater dry area component through the first air inlet and the second air inlet to discharge the internal water and form a stable local dry area;

[0026] S2. After the local dry area is formed, the induction heating coil is energized to generate high temperature in the local dry area to dry the remaining water film inside the underwater dry area component;

[0027] S3. Determine the process parameters of underwater laser additive manufacturing and plan the processing path; open the protective gas port, the protective gas flow rate in the underwater dry area component is 1.5-2.0 m3 / h, and the protective gas pressure is 0.3-0.5 MPa higher than the pressure corresponding to the operating water depth;

[0028] S4. Turn on the laser additive assembly, the rotating electric field assembly and the rotating magnetic field assembly. During the processing, when the laser additive device moves to any position, the molten pool will be located at the center of the rotating electromagnetic field.

[0029] S5. After the multi-pass composite processing of the part to be repaired is completed, the electromagnetic-assisted underwater laser additive device is towed out of the water using a traction device.

[0030] Preferably, in S4, the direction and magnitude of the Lorentz force are adjusted by adjusting the rotation speed and direction of the waterproof and pressure-resistant motor A and the waterproof and pressure-resistant motor B to control the flow of the molten pool.

[0031] Compared with the prior art, the present invention has the following beneficial technical effects:

[0032] 1. The electromagnetic-assisted underwater laser additive device is suitable for underwater in-situ processing of marine engineering equipment, including underwater in-situ repair of damaged equipment or additive manufacturing of underwater structural parts, and provides in-situ electromagnetic-assisted processing during the repair / manufacturing process, which can improve / accelerate the flow of the molten pool, refine the grains, promote the escape of bubbles, improve mechanical properties, extend service life, etc. In addition, the present invention can significantly shorten the operation time, reduce the operation cost, and improve the stability of the operation.

[0033] 2. The present invention is accompanied by the action of electromagnetic field during the composite processing of the part to be repaired; additional Lorentz force will be generated inside the molten pool formed at the center of the electromagnetic field action range, improving / accelerating the flow of the molten pool, breaking up the coarse columnar crystal structure of epitaxial growth, increasing the nucleation point, and inhibiting epitaxial growth. In addition, the speed and direction of the waterproof and pressure-resistant motor A and the waterproof and pressure-resistant motor B can be adjusted to obtain microstructures with different grain sizes in the repair area.

[0034] 3. In the present invention, the waterproof and pressure-resistant motor A and the waterproof and pressure-resistant motor B are respectively fixed inside the underwater dry area component and outside the sealed pressure-resistant housing A, the rotating electric field is placed inside the underwater dry area component, and the rotating magnetic field is placed outside the underwater dry area component, which ensures that even if the part to be repaired is a complex and changeable shape, the electromagnetic field can change with the change of the laser processing device, so that the molten pool is always at the center of the electromagnetic field. The repair area is subjected to a stable electromagnetic field from beginning to end, ensuring the uniformity of the internal organization of the repair area. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the electromagnetic-assisted underwater laser material addition device of the present invention;

[0036] Figure 2 is a schematic diagram of a gear bearing A of the present invention;

[0037] Figure 3 is a schematic diagram of a gear bearing B of the present invention;

[0038] Figure 4 It is a schematic diagram of the structure of the upper shell in the sealed pressure-resistant shell B of the present invention;

[0039] Figure 5 It is a schematic structural diagram of the lower shell in the sealed pressure-resistant shell B of the present invention.

[0040] Figure markings: 1. Sealed pressure-resistant shell A; 2. Laser additive assembly; 3. First air inlet; 4. Underwater dry area assembly; 5. Upper shell; 6. Lower shell; 7. Induction heating coil; 8. Rotating electric field assembly; 801. Negative pole of charged metal plate; 802. Gear shaft; 803. Positive pole of charged metal plate; 804. Gear bearing A; 805. Waterproof and pressure-resistant motor A; 9. Rotating magnetic field assembly; 901. N pole of permanent magnet; 902. Driving gear; 903. Transmission shaft; 904. Coupling; 905. Waterproof and pressure-resistant motor B; 906. S pole of permanent magnet; 907. Gear bearing B; 10. Parts to be repaired; 11. Connecting rod; 12. Second air inlet. DETAILED DESCRIPTION Example

[0041] like Figure 1 As shown, an electromagnetic-assisted underwater laser material-adding device proposed in the present invention comprises a housing, a laser material-adding component 2, an underwater dry area component 4, a rotating magnetic field component 9, a rotating electric field component 8 and an induction heating coil 7;

[0042] The housing includes a sealed pressure-resistant housing A1 and a sealed pressure-resistant housing B; the sealed pressure-resistant housing B includes an upper housing 5 and a lower housing 6;

[0043] The laser additive component 2 is installed inside the sealed pressure-resistant housing A1, and the underwater dry area component 4 is installed below the sealed pressure-resistant housing A1; the upper end of the underwater dry area component 4 is sealed and the lower end is open; the output end of the laser additive component 2 is inserted into the underwater dry area component 4;

[0044] A first air inlet 3 and a second air inlet 12 for communication are provided between the underwater dry area component 4 and the sealed pressure-resistant housing A1; compressed air is injected into the underwater dry area component 4 through the first air inlet 3 and the second air inlet 12 to form a local dry area;

[0045] The rotating electric field assembly 8 and the induction heating coil 7 are installed inside the underwater dry area assembly 4;

[0046] The sealed pressure-resistant casing B is installed on the outside of the underwater dry zone component 4 , and the rotating magnetic field component 9 is installed inside the sealed pressure-resistant casing B.

[0047] In this embodiment, compressed air is injected through the first air inlet 3 and the second air inlet 12 to form a local dry area inside the underwater dry area component 4. The underwater dry area component 4 is a soft magnet and can adaptively fit the surface of the part to be repaired 10 when in contact with the part to be repaired 10, thereby forming a dry area in the area between the part to be repaired 10 and the underwater dry area component 4, and cooperating with the induction heating coil 7 to remove the water film, thereby facilitating subsequent additive processing; a gap of 1-2 mm is left between the underwater dry area component 4 and the part to be repaired 10 to facilitate drainage, and at the same time, the steam generated when the induction heating coil 7 removes the water film can be discharged outward from the gap. Example

[0048] like Figure 1 and Figure 2 As shown, the rotating electric field assembly 8 includes a charged metal plate negative electrode 801, a gear shaft 802, a charged metal plate positive electrode 803, a gear bearing A804, and a waterproof and pressure-resistant motor A805; the waterproof and pressure-resistant motor A805 is fixed in the left groove at the top of the underwater dry zone assembly 4, the gear bearing A804 is fixed in the inner groove of the underwater dry zone assembly 4, the waterproof and pressure-resistant motor A805 is connected to the gear shaft 802, the gear end of the gear shaft 802 is meshed with the gear bearing A804, and the charged metal plate positive electrode 803 and the charged metal plate negative electrode 801 are fixed on the left and right sides of the gear bearing A804. The waterproof and pressure-resistant motor A805 drives the gear shaft 802 to rotate, thereby forming a rotating electric field around the molten pool.

[0049] like Figure 1 As shown, the induction heating coil 7 is fixed on the inner side wall of the underwater dry area component 4, and the induction heating coil 7 does not interfere with the movement of the above-mentioned rotating electric field component 8.

[0050] like Figure 1 and Figure 3As shown, the rotating magnetic field assembly includes a permanent magnet N pole 901, a driving gear 902, a transmission shaft 903, a coupling 904, a waterproof and pressure-resistant motor B905, a permanent magnet S pole 906, and a gear bearing B907. The waterproof and pressure-resistant motor B905 is fixed to the left side of the sealed pressure-resistant housing A1 through a connecting rod 11, one end of the transmission shaft 903 is connected to the waterproof and pressure-resistant motor B905 through a coupling 904, and the other end is connected to the driving gear 902, the driving gear 902 is meshed with the gear bearing B907, and the other end of the gear bearing B907 is fixed in the outer groove of the underwater dry zone assembly 4, and the permanent magnet N pole 901 and the permanent magnet S pole 906 are fixed on the left and right sides of the bottom of the gear bearing B907. The waterproof and pressure-resistant motor B905 drives the driving gear 902 to rotate, thereby forming a rotating magnetic field around the molten pool.

[0051] The installation position of the rotating magnetic field component 9 will enable the action area of ​​the rotating magnetic field to change with the change of the forming height and position so that the molten pool is always in the center of the action range of the rotating magnetic field.

[0052] like Figure 4 and Figure 5 The sealed pressure-resistant housing B is made of soft magnetic material and is fixed on the outside of the underwater dry area component 4. The upper shell 5 and the lower shell 6 isolate the rotating magnetic field component 9 from the water environment. When the rotating magnetic field component 9 is working, it will not cause water flow to affect the stability of the underwater dry area component 4 in forming the dry area, thereby ensuring the processing quality. Example

[0053] Based on the electromagnetic-assisted underwater laser material addition devices of Example 1 and Example 2, this embodiment provides an electromagnetic-assisted underwater laser material addition method, and the implementation process mainly includes the following steps:

[0054] 1. The electromagnetic-assisted underwater laser material-additive device is transported to the target waters by a ship and placed into the seawater. The engineering and technical personnel move the electromagnetic-assisted underwater laser material-additive device to the part of the workpiece to be repaired by controlling the cable; compressed air is injected into the underwater dry area component 4 through the first air inlet 3 and the second air inlet 12 to discharge the internal water and form a stable local dry area;

[0055] 2. After the local dry area is formed, the induction heating coil 7 is energized to generate high temperature in the local dry area to dry the remaining water film inside the underwater dry area component 4;

[0056] 3. Call the underwater laser additive process database to plan the processing path; open the protective gas port, and the protective gas in the underwater dry area component 4 reaches the specified flow and pressure;

[0057] 4. Turn on the laser additive assembly 2, the rotating electric field assembly 8 and the rotating magnetic field assembly 9. During the processing, the molten pool will be located at the center of the rotating electromagnetic field at any position of the laser additive device;

[0058] 5. After the multi-pass composite processing of the repaired part is completed, the electromagnetic-assisted underwater laser additive device is pulled out of the water using a traction device.

[0059] In step 4, the direction and magnitude of the Lorentz force are adjusted by adjusting the rotation speed and direction of the waterproof and pressure-resistant motor A805 and the waterproof and pressure-resistant motor B905 to control the flow of the molten pool.

[0060] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited thereto, and various changes can be made within the knowledge scope of technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. An electromagnetic-assisted underwater laser additive device, characterized in that: It comprises a housing, a laser material addition component (2), an underwater dry area component (4), a rotating magnetic field component (9), a rotating electric field component (8) and an induction heating coil (7); The housing comprises a sealed pressure-resistant housing A (1) and a sealed pressure-resistant housing B; the sealed pressure-resistant housing B comprises an upper housing (5) and a lower housing (6); The laser material-adding component (2) is installed inside the sealed pressure-resistant housing A (1), and the underwater dry area component (4) is installed below the sealed pressure-resistant housing A (1); the upper end of the underwater dry area component (4) is sealed and the lower end is open; the output end of the laser material-adding component (2) is inserted into the underwater dry area component (4); The underwater dry area component (4) is a soft magnet, and a gap of 1-2 mm is left between the underwater dry area component (4) and the outer surface of the part to be repaired (10); the outer side and the inner side of the side wall of the underwater dry area component (4) are respectively grooved; A first air inlet (3) and a second air inlet (12) for communication are provided between the underwater dry area component (4) and the sealed pressure-resistant housing A (1); compressed air is provided by an air compressor and injected into the underwater dry area component (4) through the first air inlet (3) and the second air inlet (12) to form a local dry area; The rotating electric field component (8) and the induction heating coil (7) are installed inside the underwater dry area component (4); The rotating electric field assembly (8) comprises a waterproof and pressure-resistant motor A (805), a gear shaft (802), a gear bearing A (804), a charged metal plate positive electrode (803) and a charged metal plate negative electrode (801); The waterproof and pressure-resistant motor A (805) is fixed in the left groove at the top of the underwater dry zone component (4), the gear bearing A (804) is fixed in the inner groove of the underwater dry zone component (4), the output end of the waterproof and pressure-resistant motor A (805) is transmission-connected with the gear shaft (802), the gear end of the gear shaft (802) is meshed with the gear bearing A (804), and the positive electrode (803) of the charged metal plate and the negative electrode (801) of the charged metal plate are respectively fixed on the left and right sides of the bottom of the gear bearing A (804); The waterproof and pressure-resistant motor A (805) drives the gear shaft (802) to rotate, thereby forming a rotating electric field around the molten pool; The action area of ​​the rotating electric field generated by the rotating electric field component (8) changes with the processing position, and the molten pool is located at the center of the action range of the rotating electric field; The sealed pressure-resistant housing B is installed on the outside of the underwater dry zone component (4), and the rotating magnetic field component (9) is installed in the sealed pressure-resistant housing B; The rotating magnetic field assembly (9) comprises a waterproof and pressure-resistant motor B (905), a transmission shaft (903), a coupling (904), a driving gear (902), a gear bearing B (907), a permanent magnet N pole (901) and a permanent magnet S pole (906); The waterproof and pressure-resistant motor B (905) is fixed to the left side of the sealed and pressure-resistant housing A (1) through a connecting rod (11); one end of the transmission shaft (903) is connected to the waterproof and pressure-resistant motor B (905) through a coupling (904), and the other end is connected to the driving gear (902), and the driving gear (902) is meshed with the gear bearing B (907); the other end of the gear bearing B (907) is fixed in the outer groove of the underwater dry area component (4), and the permanent magnet N pole (901) and the permanent magnet S pole (906) are respectively fixed on the left and right sides of the bottom of the gear bearing B (907); The waterproof and pressure-resistant motor B (905) drives the driving gear (902) to rotate, thereby forming a rotating magnetic field around the molten pool; The action area of ​​the rotating magnetic field generated by the rotating magnetic field component (9) changes with the processing position, and the molten pool is located at the center of the action range of the rotating magnetic field.

2. The electromagnetic-assisted underwater laser material addition device according to claim 1, characterized in that: The induction heating coil (7) and the rotating electric field component (8) do not interfere with each other.

3. The electromagnetic-assisted underwater laser material addition device according to claim 1, characterized in that: The upper shell (5) and the lower shell (6) of the sealed pressure-resistant shell B are both soft magnets; the sealed pressure-resistant shell B composed of the upper shell (5) and the lower shell (6) isolates the rotating magnetic field component (9) from the water environment.

4. An electromagnetically assisted underwater laser material addition method based on an electromagnetically assisted underwater laser material addition device according to any one of claims 1 to 3, characterized in that: The specific steps include: S1. The electromagnetic-assisted underwater laser material-additive device is transported to the target waters by a ship and placed into the seawater. The engineering and technical personnel move the electromagnetic-assisted underwater laser material-additive device to the part of the workpiece to be repaired by controlling the cable; compressed air is injected into the underwater dry area component (4) through the first air inlet (3) and the second air inlet (12) to discharge the internal water and form a stable local dry area; S2, after the local dry area is formed, the induction heating coil (7) is energized to generate high temperature in the local dry area, thereby drying the remaining water film inside the underwater dry area component (4); S3, determine the underwater laser additive process parameters and plan the processing path; Open the protective gas port, and the protective gas flow rate in the underwater dry zone component (4) is 1.5~2.0m 3 / h, the protective gas pressure is 0.3-0.5MPa higher than the pressure corresponding to the operating water depth; S4, turning on the laser material addition component (2), the rotating electric field component (8) and the rotating magnetic field component (9), and during the processing, when the laser material addition device is moved to any position, the molten pool will be located at the center of the rotating electromagnetic field; S5. After the multi-pass composite processing of the part to be repaired is completed, the electromagnetic-assisted underwater laser additive device is towed out of the water using a traction device.

5. The electromagnetic-assisted underwater laser material addition method according to claim 4, characterized in that: In S4, the direction and magnitude of the Lorentz force are adjusted by adjusting the rotation speed and direction of the waterproof and pressure-resistant motor A (805) and the waterproof and pressure-resistant motor B (905) to control the flow of the molten pool.

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