Automatic TIG (Tungsten Inert Gas) welding method for reducing 6-series aluminum alloy cracks and craters

Abstract

The invention discloses an automatic TIG welding method for reducing 6-series aluminum alloy cracks and craters. The automatic TIG welding method comprises the following steps that 1, the surface of an aluminum alloy part is subjected to acid pickling; 2, the aluminum alloy part is assembled and clamped; 3, the shape of the end of the tungsten electrode of the welding gun is adjusted; 4, a welding program is compiled according to the structure of the 6-series aluminum alloy part; 5, adding a delay instruction after the arcing instruction; 6, the delayed wire feeding time is adjusted; 7, adding a delay instruction after the arc suppression point instruction; 8, adjusting the delayed wire collecting time; 9, welding parameters are adjusted; and 10, a program is started for welding. According to the method, the arc starting time, the arc stopping time, the welding current and other parameters are changed, and the problems of cracks and craters generated in the automatic welding process of the 6-series aluminum alloy can be effectively reduced or even eliminated.

Description

Technical Field

[0001] The present invention belongs to the technical field of aluminum alloy welding, and particularly relates to an automatic TIG welding method for reducing cracks and arc pits in 6-series aluminum alloy during automatic welding. Background Art

[0002] With the development of industrial intelligent manufacturing, the application of automatic welding in enterprises is gradually increasing. For pressure vessels made of 6-series aluminum alloy materials, high weld quality is required. Cracks that appear in the weld often cause stress concentration. When subjected to external forces, the crack propagation reduces the structural strength of the workpiece, thereby leading to a decline in the safety performance and service life of the product. Therefore, to improve the weld quality of automatic welding of 6-series aluminum alloy products, the control of weld cracks becomes the key point.

[0003] After analyzing the material characteristics of 6-series aluminum alloy and the process factors of TIG automatic welding, the applicant believes that the main causes of cracks and arc pits generated during automatic TIG welding of 6-series aluminum alloy include the following two points:

[0004] 1. Sudden cooling of the molten pool and stress concentration: When welding and arc extinguishing, the sudden disappearance of the arc causes the center of the molten pool to lose the heat source, and the cooling rate increases sharply, triggering stress concentration. Superimposed with the action of residual tensile stress, it leads to radioactive cracks.

[0005] 2. Mismatch of process parameters: If the welding current is too high or the arc extinguishing speed is too fast, the depth-width ratio of the molten pool increases, further aggravating segregation and stress concentration.

[0006] Based on the above reasons, by maintaining the molten pool state and designing reasonable process parameters for automatic TIG welding, it is possible to reduce the cracks and arc pits generated in the weld during automatic welding of 6-series aluminum alloy. Summary of the Invention

[0007] The present invention aims to provide an automatic TIG welding method for reducing cracks and arc pits in 6-series aluminum alloy during automatic welding, so as to reduce the problems of weld cracks and arc pits during automatic TIG welding of aluminum alloy.

[0008] To achieve the above object, the present invention adopts the following technical solutions:

[0009] An automatic TIG welding method for reducing cracks and arc pits in 6-series aluminum alloy, including programming an automatic welding program for 6-series aluminum alloy parts, wherein:

[0010] Add a delay instruction after the arc starting instruction to control the robot to stay at the starting point of the weld to start the arc until the molten pool is formed;

[0011] Adjust the delay wire feeding time to ensure that the wire feeding starts after the molten pool is formed and before the robot starts the welding movement;

[0012] Add a delay instruction after the arc-ending instruction to control the robot to stay at the end of the weld seam for a period of time.

[0013] Adjust the delay wire-feeding time to ensure that wire-feeding stops after the robot stays at the end of the weld seam and arcs.

[0014] It should be noted that the robot mentioned in the present invention is a common welding manipulator in the welding field, and the welding manipulator required in the present invention has at least a welding torch and a wire-feeding unit. The welding manipulator can be a 4-axis, 5-axis or 6-axis manipulator.

[0015] Furthermore, the automatic TIG welding method for reducing cracks and craters in 6000 series aluminum alloy parts also includes pickling the surface of 6000 series aluminum alloy parts.

[0016] Furthermore, after pickling, the automatic TIG welding method for reducing cracks and craters in 6000 series aluminum alloy parts also includes assembling and clamping the 6000 series aluminum alloy parts.

[0017] Furthermore, after the assembling and clamping, it also includes adjusting the shape of the tungsten electrode tip to make the tungsten electrode tip a smooth sphere and ensuring that the spherical appearance is silver-white.

[0018] Furthermore, the automatic TIG welding method for reducing cracks and craters in 6000 series aluminum alloy parts also includes adjusting welding parameters, which include pulse frequency, pulse width ratio, pulse current ratio, tungsten electrode diameter, nozzle diameter, welding current, welding speed, wire-feeding speed and argon gas flow rate.

[0019] Furthermore, the welding current is adjusted according to the thickness of the 6000 series aluminum alloy parts and the influence on the depth-width ratio of the molten pool.

[0020] As an option, when adjusting the delay wire-feeding time, ensure that wire-feeding starts 0.5 seconds before the robot starts.

[0021] As an option, after adding a delay instruction to the arc-ending instruction, ensure that arcing occurs 3 to 5 seconds after the robot stops running.

[0022] Compared with the prior art, the present invention addresses the problems of cracks and craters in the automatic TIG welding of 6000 series aluminum alloy. Starting from the control of the time nodes of starting and ending arcs, the start, stop, wire-feeding, and wire-receiving of the welding robot are associated with starting and ending arcs. Furthermore, by cooperating with the adjustment of welding parameters, the problems of cracks and craters are solved. The solution of the present invention is simple and effective, not affected by the weld shape (straight line or broken line or curve), and can effectively solve the problems of cracks and craters generated during the automatic TIG welding of 6000 series aluminum alloy. Description of the Drawings

[0023] Figure 1 It is a schematic diagram of the adjustment relationship between the welding torch and the welding wire during the TIG automatic welding process.

[0024] Figure 2 It is a schematic diagram of the time line of the TIG automatic welding process;

[0025] In the figure: 1 - welding torch, 2 - tungsten electrode, 3 - welding arc influence area, 4 - welding wire, 5 - molten pool, 6 - robot moving direction. Specific implementation manners

[0026] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. However, it should not be understood that the scope of the subject matter of the present invention is limited to the following embodiments. Without departing from the above technical idea of the present invention, all modifications, substitutions, and changes made according to ordinary technical knowledge and customary means in the art are included in the scope of the present invention.

[0027] As Figure 1 and Figure 2 shown, the automatic TIG welding method for 6-series aluminum alloy in the present invention includes the following steps:

[0028] Step 1: Pickle the surface of the 6-series aluminum alloy parts;

[0029] Step 2: Assemble and clamp the 6-series aluminum alloy parts;

[0030] Step 3: Adjust the shape of the end of the tungsten electrode 2 of the welding torch 1 on the TIG automatic welding robot so that the end of the tungsten electrode 2 is a smooth sphere and ensure that the spherical appearance is silver-white;

[0031] Step 4: Program the automatic welding program according to the workpiece structure (components made of 6-series aluminum alloy material);

[0032] Step 5: After the arc-starting instruction, add a delay instruction, and this delay instruction controls the robot to start the arc and stay in place (the starting point of the weld) until the molten pool 5 is formed;

[0033] Step 6: Adjust the delay wire-feeding time, as Figure 2 , ensure that the wire-feeding starts after the molten pool 5 is formed and before the robot starts the welding movement (the arrow in Figure 1 is the robot moving direction 6, and the welding arc influence area 3 is also drawn at the same time), and the welding wire 4 should be quickly fed into the molten pool 5 after the molten pool 5 is formed, that is, the delay wire-feeding time corresponds to the robot delay start (the robot delays to start after adding the delay instruction), and the wire-feeding delay start is about 0.5 seconds less than the robot start delay;

[0034] Step 7: After the arc-ending instruction, add a delay instruction to control the robot to stay in place (the end point of the weld) for 3 to 5 seconds when ending the arc;

[0035] Step 8: Adjust the wire retraction delay time to ensure that wire retraction occurs after the robot stops arc welding in place, such as Figure 2 .

[0036] Step 9: Adjust the welding parameters. For example, for a 6-series aluminum alloy plate with a thickness of 4 mm, the parameter adjustments include a pulse frequency of 1.5 Hz; a pulse width ratio of 50%; a pulse current ratio of 50%; a tungsten electrode diameter of 3 mm; a nozzle diameter of 14 mm; an argon gas flow rate of 12 mL / min; a welding current of 283 A (taking into account the thickness of the 6-series aluminum alloy plate and the reduction of the depth-width ratio of the molten pool 5); a welding speed of 210 mm / min; and a wire feeding speed of 1800 mm / min.

[0037] Step 10: Start the automatic welding program to perform TIG automatic welding.

[0038] As described above, it is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in the present application should be covered by the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. An automatic TIG welding method for reducing cracks and arc pits in 6-series aluminum alloy, characterized in that, Including the preparation of an automatic welding program for 6-series aluminum alloy parts, where: Add a delay instruction after the arc starting instruction to control the robot to stay at the starting point of the weld seam until the molten pool is formed. Adjust the delay wire feeding time to ensure that the wire feeding starts after the molten pool is formed and before the robot starts the welding movement. Add a delay instruction after the arc extinguishing instruction to control the robot to stay at the end point of the weld seam for a period of time. Adjust the delay wire withdrawing time to ensure that the wire withdrawing occurs after the robot stops at the end point of the weld seam for arc extinguishing.

2. An automatic TIG welding method for reducing cracks and arc pits in 6-series aluminum alloy according to claim 1, characterized in that, It also includes pickling the surface of 6-series aluminum alloy parts.

3. An automatic TIG welding method for reducing cracks and arc craters in 6-series aluminum alloy according to claim 2, characterized in that, After the pickling, it also includes assembling and clamping the 6-series aluminum alloy parts.

4. An automatic TIG welding method for reducing cracks and arc pits in 6-series aluminum alloy according to claim 3, characterized in that, After the assembling and clamping, it also includes adjusting the shape of the tungsten electrode tip to make the tungsten electrode tip a smooth sphere and ensuring that the spherical appearance is silver-white.

5. An automatic TIG welding method for reducing cracks and arc pits in 6-series aluminum alloy according to claim 1, characterized in that, It also includes adjusting the welding parameters, which include pulse frequency, pulse width ratio, pulse current ratio, tungsten electrode diameter, nozzle diameter, welding current, welding speed, wire feeding speed, and argon gas flow rate.

6. An automatic TIG welding method for reducing cracks and arc pits in 6-series aluminum alloy according to claim 5, characterized in that: The welding current is adjusted according to the thickness of the 6-series aluminum alloy parts and the influence on the depth-width ratio of the molten pool.

7. An automatic TIG welding method for reducing cracks and arc pits in 6-series aluminum alloy according to claim 1, characterized in that: When adjusting the delay wire feeding time, ensure that the wire feeding starts 0.5 seconds before the robot starts.

8. An automatic TIG welding method for reducing cracks and arc pits in 6-series aluminum alloy according to claim 1, characterized in that: After adding the delay instruction to the arc extinguishing instruction, ensure that the arc is extinguished 3 - 5 seconds after the robot stops running.

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