Multi-beam galvanometer pulse laser-TIG electric arc swing narrow gap welding method and device

Abstract

The invention relates to a multi-beam galvanometer pulse laser-TIG electric arc swing narrow gap welding method and device. The device comprises a galvanometer and a TIG welding gun, the galvanometer is connected with a mechanical arm, the mechanical arm is connected with a laser and a programmer, the TIG welding gun is connected with a mechanical control device, and the mechanical control device is connected with a control system and an electric arc welding machine. Continuous accumulation of heat can be reduced through intermittent output of pulse laser, and heat concentration is avoided; pulse laser is used for releasing energy in a short pulse mode, when each pulse acts, the stirring effect on a molten pool is stronger, the liquidity of liquid metal in the molten pool can be effectively improved, then multiple beams of pulse laser are controlled through a galvanometer, each beam of pulse laser is provided with different scanning parameters to be combined with a swing arc, stirring on the molten pool is further enhanced, and the welding quality of the molten pool is improved. The temperature distribution and the flowing state in the molten pool are improved, continuous accumulation of heat is further reduced, heat distribution is optimized, excessive concentration of heat in a certain local area is avoided, and side wall fusion is facilitated.

Description

Technical Field

[0001] The invention relates to a narrow gap welding method and device, and in particular to a multi-beam galvanometer pulse laser-TIG arc swing narrow gap welding method and device. Background Art

[0002] With the development of economy, major equipment in aerospace, nuclear power, petrochemical and marine engineering fields are becoming larger and larger, and the application of high-performance thick plate metal materials is becoming more and more extensive. For thick plate and ultra-thick plate metal materials, the traditional thick plate welding process has low welding efficiency, large amount of consumables, and increased welding cost, which can no longer meet the requirements of modern industry for welding. Compared with the traditional welding process with large groove, the narrow gap welding groove has a small gap, small heat input, and good welding joint performance. It is suitable for welding applications of stainless steel, carbon steel, high-strength steel and different welding positions.

[0003] According to the welding method used, narrow gap welding can be divided into: narrow gap tungsten inert gas welding (NG-TIG), narrow gap metal arc welding (NG-GMAW), narrow gap submerged arc welding (NG-SAW) and narrow gap laser welding (NG-LBW). Among them, narrow gap TIG welding technology is studied. Narrow gap TIG welding inherits the characteristics of traditional TIG welding, such as low heat input, high arc stability, and few welding defects. It can achieve full-position welding, and the welding process is easy to automate. Based on the advantages of narrow gap TIG welding, many chemical and nuclear power industries have begun to develop narrow gap equipment suitable for their own working conditions.

[0004] However, the narrow gap TIG welding technology may cause poor side wall fusion and arc climbing along the side wall. Therefore, some researchers have proposed to achieve narrow gap TIG side wall fusion by swinging the arc, which controls the overall swing of the welding torch, electromagnetically or using a special conductive nozzle to control the arc to move in a certain trajectory within the groove, thereby expanding the arc action range and increasing the side wall melting depth.

[0005] However, in the process of swing arc narrow gap welding, if the amplitude, frequency or mode of arc swing is improper, the arc may be unstable, resulting in unstable contact between the arc and the molten pool or other parts of the workpiece. This unstable contact may cause short circuit transition, thus forming spatter. Spatter will take away part of the heat, resulting in uneven heat distribution in the weld area, affecting the heating effect of the side wall, resulting in poor fusion of the side wall, and low efficiency of single arc welding, large welding heat input, and large deformation of the weld joint.

[0006] In view of the above problems, in addition to optimizing the arc process parameters, ensuring that the swing process is smooth and regular, and avoiding sudden changes and excessive amplitudes. Some researchers have proposed adding galvanometer lasers, such as the patents with publication numbers CN118081095A and CN108788471A. For conventional galvanometer laser-arc hybrid welding, the laser is a continuous laser, and the arc is stabilized by the laser to reduce the fluctuation and instability of the arc, so that the arc burns more stably, and the continuous laser and arc are controlled by the galvanometer to cooperate to improve the welding efficiency and improve the heat distribution in the weld, which has a certain improvement effect on the side wall unfusion. However, in conventional galvanometer laser-arc hybrid welding, a beam of high-power continuous laser is used as the main heat source, and the arc is only used as an auxiliary heat source. Therefore, the continuous laser will continue to provide high energy density during the narrow gap welding of thick plates, and the stirring effect of the continuous laser on the molten pool is relatively limited. In the special spatial structure of the narrow gap, the flow of liquid metal in the molten pool is insufficient, and the heat may be highly concentrated in the weld and its vicinity, resulting in the side wall area not being fully melted due to insufficient heat. Even though the galvanometer can control the continuous laser oscillation, if the oscillation parameters are not appropriate, such as small oscillation amplitude, inappropriate frequency, etc., the continuous laser energy will not have an ideal effect on the side wall, and therefore it cannot guarantee that the side wall metal is fully melted. Summary of the invention

[0007] Purpose of the invention: The purpose of the present invention is to propose a multi-beam galvanometer pulsed laser-TIG arc swing narrow gap welding method and device to improve the temperature distribution and flow state in the molten pool, avoid excessive concentration of heat in a certain local area, and help side wall fusion.

[0008] Technical solution: The present invention comprises the following steps:

[0009] Beveling of thick plates and cleaning before welding;

[0010] Fix the TIG welding gun on the mechanical control device, adjust the placement angle of the TIG welding gun, and set the TIG arc swing process parameters;

[0011] Control the robot arm through the programmer to adjust the galvanometer to be level with the workbench and the distance between the galvanometer and the specimen;

[0012] Set the multi-beam pulse laser scanning path, scanning frequency, scanning amplitude, TIG arc swing path, swing parameters, and adjust the current type, current and voltage through the arc welding machine;

[0013] The arc generated by the TIG welding gun is mechanically controlled to perform narrow gap thick plate welding in a Z-shaped swinging manner, and the galvanometer is used to control multiple pulse lasers to synchronize with the arc in a Z-shaped scanning manner with different scanning parameters.

[0014] The TIG arc swing process parameters are: swing frequency of 20-200 Hz, swing amplitude of 12-20 mm; TIG arc placement angle is 40-60° with the vertical direction, the distance between the TIG tip and the workpiece is 2-3 mm, and the distance between the laser and the TIG tip is 2-3 mm.

[0015] The scanning frequency of the multi-beam pulse laser is 100-300Hz, the scanning amplitude is 1.5-2.5mm, the pulse width is 4ms, the pulse frequency is 50-100Hz, the duty cycle is 20%-40%, the pulse laser power is 2200W-2800W, the TIG current is 190-230A, the voltage is 10V, and the welding speed is 7-15mm / s.

[0016] The thickness of the thick plate is 50-100 mm, and the groove angle is 0-5°.

[0017] A multi-beam galvanometer pulse laser-TIG arc swing narrow gap welding device comprises a galvanometer and a TIG welding gun, wherein the galvanometer is connected to a mechanical arm, the mechanical arm is connected to a laser and a programmer, the TIG welding gun is connected to a mechanical control device, and the mechanical control device is connected to a control system and an arc welding machine.

[0018] The galvanometer controls multiple beams of pulsed laser generated by the laser to be perpendicular to the workbench and synchronized with the arc in a zigzag scanning manner.

[0019] The programmer controls the robot arm to adjust the galvanometer to be level with the workbench and the distance between the galvanometer and the sample piece.

[0020] The mechanical control device controls the placement angle of the TIG welding gun, and the arc welding machine adjusts the current type and current voltage.

[0021] The mechanical arm is connected to the laser through an optical fiber.

[0022] The arc welding machine is connected with a gas cylinder which delivers argon gas to protect the welding area.

[0023] Beneficial effects: The present invention utilizes the intermittent output of pulsed laser to reduce the continuous accumulation of heat and avoid heat concentration; utilizes pulsed laser to release energy in the form of short pulses, and each pulse has a stronger stirring effect on the molten pool when it acts, which can effectively improve the fluidity of the liquid metal in the molten pool; and then controls multiple beams of pulsed lasers through a galvanometer, and sets different scanning parameters for each beam of pulsed laser in combination with the swinging arc, which can further enhance the stirring of the molten pool, improve the temperature distribution and flow state in the molten pool, further reduce the continuous accumulation of heat, optimize the heat distribution, and avoid excessive concentration of heat in a certain local area, which is conducive to the fusion of the side walls; adopts a mechanical control system to control the arc generated by the TIG welding gun to swing in a Z-shaped path for narrow gap thick plate welding, and utilizes a galvanometer to control multiple beams of pulsed lasers to swing synchronously with the arc in a Z-shaped scanning manner; by combining multiple beams of galvanometer pulsed lasers with the swinging TIG arc, a stable arc is achieved, welding efficiency is improved, heat distribution in the weld is improved, and side wall fusion is promoted, which is beneficial to the improvement of the mechanical properties of thick plate weldments and the improvement of weldment quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the overall structure of the present invention. DETAILED DESCRIPTION

[0025] The present invention will be further described below in conjunction with the accompanying drawings.

[0026] Example 1

[0027] like Figure 1 As shown, the multi-beam galvanometer pulse laser-TIG arc swing narrow gap welding device of this embodiment includes a galvanometer 4 and a TIG welding gun 8, the galvanometer 4 is connected to the mechanical arm 3, the mechanical arm 3 is connected to the laser 1 and the programmer 5, and the mechanical arm 3 and the laser 1 are connected through an optical fiber 2; the galvanometer 4 controls the multi-beam pulse laser generated by the laser to be perpendicular to the workbench and synchronized with the arc in a zigzag scanning manner. The programmer 5 controls the mechanical arm 3 to adjust the galvanometer 4 horizontal to the workbench and the distance between the galvanometer 4 and the sample. The laser type, laser power, scanning path, scanning frequency, and scanning amplitude of the multi-beam galvanometer pulse laser are uniformly controlled by a computer program, and the parameters are set directly in the computer. The scanning frequency of the multi-beam pulse laser is 100-300Hz, the scanning amplitude is 1.5-2.5mm, the pulse width is 4ms, and the pulse frequency is 50-100Hz. The duty cycle is 20%-40%. The pulse laser power is 2200W-2800W.

[0028] The TIG welding gun 8 is connected to the mechanical control device 7, and the mechanical control device 7 is connected to the control system 10 and the arc welding machine 6, and the arc welding machine 6 is connected to the gas cylinder 9. The mechanical control device 7 controls the placement angle of the TIG welding gun 8, and the arc welding machine 6 adjusts the current type and the current voltage. The gas cylinder 9 delivers argon gas to protect the welding area. The TIG arc swing path, swing parameters, and gas shielding gas are uniformly called by the mechanical control system, and the parameters are directly set in the control system 10. The trajectory of the TIG arc swing is Z-shaped, the swing frequency of the TIG arc is 20-200Hz, and the swing amplitude is 12-20mm according to the groove width. The TIG arc placement angle is 40-60° with the vertical direction. The distance between the TIG tip and the workpiece is 2-3mm, and the distance between the laser and the TIG tip is 2-3mm. The TIG current is 190-230A, the voltage is 10V, and the welding speed is 7-15mm / s.

[0029] The thickness of the workpiece to be measured is 50-100mm, and the groove angle is 0-5°.

[0030] By adding multiple beams of galvanometer low-power pulsed lasers, the pulsed laser releases energy in the form of short pulses. Each pulse has a stronger stirring effect on the molten pool, which can effectively improve the fluidity of the liquid metal in the molten pool. The duration of each pulse is very short, and there is an interval between pulses. This characteristic enables the pulsed laser to release huge energy in a very short time. This intermittent output can reduce the continuous accumulation of heat and avoid heat concentration. In addition, by changing to multiple beams of pulsed lasers, and then controlling multiple beams of pulsed lasers with different scanning parameters through galvanometers and combining them with swinging arcs, the stirring of the molten pool can be further enhanced, the temperature distribution and flow state in the molten pool can be improved, the continuous accumulation of heat can be further reduced, the heat distribution can be optimized, and the overheating phenomenon in the center area of ​​the weld can be reduced, so that the side wall metal absorbs enough energy and fully melts, thereby ensuring the fusion of the side wall.

[0031] Example 2

[0032] The multi-beam galvanometer pulse laser-TIG arc swing narrow gap welding method of this embodiment includes the following steps:

[0033] S1. Bevel the thick plate and clean it before welding; the metal materials of thick plate mainly include stainless steel, carbon steel, high-strength steel, etc.

[0034] S2. Fix the workpiece to be welded on the workbench;

[0035] S3. Set TIG arc swing process parameters according to groove width, angle and other parameters

[0036] Fix the TIG welding gun on the mechanical control device to adjust the placement angle of the TIG welding gun, extend the thin copper tube of the TIG welding gun and place it in the middle of the groove unchanged; use inert gas argon to protect the welding gun; the swing frequency is 20-200Hz, and the swing amplitude is 12-20mm; the TIG arc placement angle is 40-60° with the vertical direction, the distance between the TIG tip and the workpiece is 2-3mm, and the distance between the laser and the TIG tip is 2-3mm.

[0037] S4, controlling the robot arm through the programmer to adjust the galvanometer to be level with the workbench and the distance between the galvanometer and the sample;

[0038] S5. Set the scanning path, scanning frequency, scanning amplitude, TIG arc swing path, and swing parameters of the multi-beam pulse laser, and adjust the current type, current and voltage through the arc welding machine; the scanning frequency of the multi-beam pulse laser is 100-300Hz, the scanning amplitude is 1.5-2.5mm, the pulse width is 4ms, the pulse frequency is 50-100Hz, the duty cycle is 20%-40%, the pulse laser power is 2200W-2800W, the TIG current is 190-230A, the voltage is 10V, and the welding speed is 7-15mm / s.

[0039] S6. The arc generated by the TIG welding gun is mechanically controlled to perform narrow gap thick plate welding in a Z-shaped swinging manner, and a galvanometer is used to control multiple pulsed lasers to synchronize with the arc in a Z-shaped scanning manner with different scanning parameters.

[0040] The present invention utilizes the intermittent output of pulsed laser to reduce the continuous accumulation of heat and avoid heat concentration. The pulsed laser is used to release energy in the form of short pulses. When each pulse acts, the stirring effect on the molten pool is stronger, which can effectively improve the fluidity of the liquid metal in the molten pool. Then, multiple pulsed lasers are controlled by a galvanometer. Different scanning parameters are set for each pulsed laser and combined with the swinging arc to further enhance the stirring of the molten pool, improve the temperature distribution and flow state in the molten pool, further reduce the continuous accumulation of heat, optimize the heat distribution, and avoid excessive concentration of heat in a local area, which is conducive to the fusion of the side walls. A mechanical control system is used to control the arc generated by the TIG welding gun to perform narrow gap thick plate welding in a Z-shaped path swing mode, and a galvanometer is used to control multiple pulsed lasers to swing synchronously with the arc in a Z-shaped scanning mode. By combining multiple galvanometer pulsed lasers with the swinging TIG arc, a stable arc is achieved, welding efficiency is improved, heat distribution in the weld is improved, side wall fusion is promoted, and the mechanical properties of thick plate weldments are improved, and the quality of weldments is improved.

Claims

1. A multi-beam galvanometer pulse laser-TIG arc swing narrow gap welding method, characterized in that: The following steps are involved: Beveling of thick plates and cleaning before welding; Fix the TIG welding gun on the mechanical control device, adjust the placement angle of the TIG welding gun, and set the TIG arc swing process parameters; Control the robot arm through the programmer to adjust the galvanometer to be level with the workbench and the distance between the galvanometer and the specimen; Set the multi-beam pulse laser scanning path, scanning frequency, scanning amplitude, TIG arc swing path, swing parameters, and adjust the current type, current and voltage through the arc welding machine; The arc generated by the TIG welding gun is mechanically controlled to perform narrow gap thick plate welding in a Z-shaped swinging manner, and the galvanometer is used to control multiple pulse lasers to synchronize with the arc in a Z-shaped scanning manner with different scanning parameters.

2. A multi-beam galvanometer pulse laser-TIG arc swing narrow gap welding method according to claim 1, characterized in that: The TIG arc swing process parameters are: swing frequency of 20-200 Hz, swing amplitude of 12-20 mm; TIG arc placement angle is 40-60° with the vertical direction, the distance between the TIG tip and the workpiece is 2-3 mm, and the distance between the laser and the TIG tip is 0-20 mm.

3. The multi-beam galvanometer pulse laser-TIG arc swing narrow gap welding method according to claim 1, characterized in that: The scanning frequency of the multi-beam pulse laser is 100-300 Hz, the scanning amplitude is 1.5-2.5 mm, the pulse frequency is 50-100 Hz, the duty cycle is 20%-35%, the pulse laser power is 2200W-2800W, the TIG current is 190-230A, and the welding speed is 7-15mm / s.

4. The multi-beam galvanometer pulse laser-TIG arc swing narrow gap welding method according to claim 1, characterized in that: The thickness of the thick plate is 50-100 mm, and the groove angle is 0-5°.

5. A multi-beam galvanometer pulse laser-TIG arc swing narrow gap welding device, characterized in that: It includes a galvanometer and a TIG welding gun. The galvanometer is connected to a mechanical arm. The mechanical arm is connected to a laser and a programmer. The TIG welding gun is connected to a mechanical control device. The mechanical control device is connected to a control system and an arc welding machine.

6. The multi-beam galvanometer pulse laser-TIG arc swing narrow gap welding device according to claim 5, characterized in that: The galvanometer controls multiple beams of pulsed laser generated by the laser to be perpendicular to the workbench and synchronized with the arc in a zigzag scanning manner.

7. The multi-beam galvanometer pulse laser-TIG arc swing narrow gap welding device according to claim 5, characterized in that: The programmer controls the robot arm to adjust the galvanometer to be level with the workbench and the distance between the galvanometer and the sample piece.

8. The multi-beam galvanometer pulse laser-TIG arc swing narrow gap welding device according to claim 5, characterized in that: The mechanical control device controls the placement angle of the TIG welding gun, and the arc welding machine adjusts the current type and current voltage.

9. The multi-beam galvanometer pulse laser-TIG arc swing narrow gap welding device according to claim 5, characterized in that: The mechanical arm is connected to the laser through an optical fiber.

10. The multi-beam galvanometer pulse laser-TIG arc swing narrow gap welding device according to claim 5, characterized in that: The arc welding machine is connected with a gas cylinder.

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