Welding device and welding method for thick plate mounting supporting point assembly

Abstract

The invention relates to the technical field of aero-engine welding, in particular to a welding device and method for a thick plate installation supporting point assembly. The welding device comprises a front face device and a back face device, and during front face welding and back face welding, when the flange edge is placed on the positioning assembly, the flange edge is in butt joint with a pre-placed to-be-welded supporting point welding seam to form an X groove. An X groove is subjected to pre-welding cleaning, positioned welding and backing welding through manual argon arc welding and wire filling through automatic argon arc welding, and the complete welding process is achieved. Compared with manual argon arc welding, the reasonable machining method and suitable welding parameters are adopted, the appearance quality of welding seams of automatic argon arc welding is remarkably improved, and the welding deformation control effect on the titanium alloy X-shaped groove assembly is good.

Description

Technical Field

[0001] The invention relates to the technical field of aviation engine welding, and in particular to a welding device and a welding method for a thick plate mounting support point assembly. Background Art

[0002] The mounting support assembly is a titanium alloy welded structural part formed by welding the mounting support and the mounting support flange. The mounting support assembly is welded with a titanium alloy thick plate with a wall thickness of 8-10mm. It is used to connect the external pipe accessories of the casing. It is subjected to tension during long-term operation, and the weld strength and reliability need to be improved. Since the mounting support assembly is a titanium alloy thick plate, it is easy for the weld to not be fully welded, so an X-shaped groove is opened at the weld joint to be welded. At present, manual argon arc welding is used, which is divided into two single-sided welding on the front and back sides. Each single side is divided into three welding passes: base welding, filling welding and mask welding. Among them, the base welding is a single-sided welding and double-sided forming. Only one bottom surface is needed on the front and back sides. A total of 5 welding passes are required to complete a piece of welding. There is also an upper limit to the manual welding wire filling speed. This welding method has the problem of high heat input, which is easy to cause serious welding stress and deformation, affecting performance.

[0003] At present, the argon arc welding process for mounting support assembly mainly has the following problems:

[0004] First, the welds have incomplete penetration, pores and tungsten inclusions. The X-ray pass rate is low and the welding quality is unstable. Manual argon arc welding is used for multi-layer and multi-pass welding. The thickness of the joint to be welded at the installation support assembly is 8mm, which is prone to incomplete penetration and tungsten inclusion defects. After the defects are detected by X-ray inspection, it is more difficult to clean the welds of thick plates.

[0005] Secondly, there are problems with parts deformation and oxidation. Affected by the structure of the parts, the heat input is highly concentrated, and manual welding also has the problem of parts deformation caused by uneven heat input on the front and back sides. Titanium alloys are extremely chemically active and easily react with oxygen, hydrogen, and nitrogen at high temperatures. They are very easy to oxidize during welding. Currently, manual welding has serious problems with weld and heat-affected zone oxidation. Therefore, when welding, it is necessary to pay attention to argon protection on both sides of the weld, pay attention to evenly distribute the weld points when positioning welding, and perform manual base welding after completing the positioning welding. The weld penetration rate during base welding must reach 100% to avoid incomplete penetration of automatic welding welds;

[0006] Third, the welding efficiency is low. A single engine has two parts. Since the thickness of the parts is 8mm, in order to ensure the welding quality, an X-shaped groove is opened. Manual argon arc welding requires multiple layers and multiple passes. It takes 3 minutes to weld the base welding of a part. After the base welding, it takes 6 minutes to fill the welds on the front and back sides and 5 minutes to cover the front and back sides. It takes 14 minutes to weld one part manually, and about 28 minutes for each unit. After welding 5 parts manually in a row, the welding must be stopped for 10-20 minutes to allow the welding fixture and welding gun to be air-cooled to ensure the quality of the subsequent welded parts.

[0007] Fourth, the weld formation is unstable and depends more on the welder's technique. It is easy to have defects such as interlayer, tungsten inclusion, and pores. In particular, the pore interlayer defect is difficult to clean for thick-walled titanium alloys with high hardness.

[0008] Fifth, to complete the installation support point assembly for the base welding, it is necessary to perform automatic welding with wire filling on the front and back sides of the weld respectively. During welding, the front and back sides of the weld need to be protected by argon gas. It is difficult to balance the alignment of the weld and the protection during welding. Summary of the invention

[0009] In order to solve the above technical problems, the present invention provides a welding device and a welding method for a thick plate mounting support point assembly.

[0010] The specific technical solutions are as follows:

[0011] A welding device for a thick plate mounting support assembly, the mounting support assembly comprising a flange edge and a support point, one side of the flange edge being a characteristic edge C, and a mounting opening being provided in the middle of the other side for matching welding with the support point, the two sides of the mounting opening being characteristic edge A and characteristic edge B respectively; the welding points of the support point and the mounting opening are both butt-jointed after processing to form an X-groove.

[0012] The welding device includes a front device and a back device, and the structures of the two are symmetrical with the diameter as the symmetry axis; the front device includes a positioning plate, a centering shaft and a positioning assembly, the positioning plate is a circular plate, and a circular pre-set groove is opened in the center of the top surface at the center of the circle, and the support point to be welded is pre-placed; the bottom surface at the center of the circle is fixed to the clamp of the machine tool through the centering shaft; the central opening of the centering shaft is used to install an argon gas pipe, which is connected to the external argon gas bottle for gas supply; the positioning assembly is protrudingly arranged on the top surface of the positioning plate, including a positioning edge A, a positioning edge B and a positioning edge C, which are respectively limited by the characteristic edges A, B and C of the flange edge, so that when the front side of the flange edge is placed on the positioning assembly, it is connected to the pre-placed weld of the support point to be welded to form an X-groove.

[0013] A welding method for a thick plate mounting support assembly comprises the following steps:

[0014] (1) Cleaning before welding

[0015] For titanium alloy parts, it is necessary to arrange a pickling process before welding. After pickling, mechanical grinding is used to make the front and back sides and end faces of the parts to be welded present a metallic luster. Grinding the end faces and grooves of the joints is allowed to ensure the assembly gap and penetration rate. Wear gloves when welding and turning over titanium alloy parts to prevent grease and other substances from contaminating the parts.

[0016] (2) Manual argon arc welding for positioning welding and base welding

[0017] The tack welding and base welding of the mounting point assembly are carried out by manual argon arc welding. Titanium alloy materials are prone to oxidation and discoloration during welding. It is necessary to pay attention to the argon protection on both the front and back sides of the weld. Pay attention to evenly distribute the welding points during tack welding. After completing the tack welding, manual base welding is carried out. The weld penetration rate during base welding must reach 100% to avoid the situation where the automatic weld seam is not fully penetrated;

[0018] (3) Automatic argon arc welding for wire filling

[0019] The installation support point assembly that has completed the base welding needs to be automatically argon arc welded with wire filling on the front and back sides of the weld respectively, and argon gas protection is required for the front and back sides of the weld during welding; a set of welding fixtures is required for automatic welding of the front and back sides respectively, and the installation support point assembly that has completed the base welding is placed in the welding fixture, and automatic welding is started; after each batch of parts has completed the automatic welding of the front side, the back side welding fixture is replaced to carry out automatic argon arc welding of the back side of the installation support point assembly with wire filling.

[0020] The automatic argon arc welding of the filling wire in step (3) is automatically fed by a manipulator, and the coiled wire used by the manipulator is coiled in a compressed spiral shape, and the wire feeding angle is kept consistent. When the coiled wire in the spiral shape is loose and deformed, the deformed wire segment is cut off before welding.

[0021] The steps of the automatic argon arc welding with filler wire described in step (3) are as follows: after the manipulator moves to the designated point near the weld, it touches the part perpendicular to the direction of the part, and after receiving the feedback signal, the welding gun is raised by 2.5 mm and the arc is started for 1 second; the current increases from 100 A to 170 A, and after staying in place for 1-2 seconds, after burning out a molten pool of suitable size, the wire is swung in place for 2 seconds, and the filler wire is fed in after 1 second, running along the welding track and swinging horizontally, and the tungsten electrode swing distance is 2 mm;

[0022] The welding process tracks the welding height according to the arc voltage feedback. The larger the welding pulse peak welding current is, the larger the melt pool is, and more welding wire is added. When it is converted to the base value, the melt pool is relatively small, which reduces the addition of welding wire and prevents defects such as spatter and interlayer.

[0023] The wire feeding angle and weld direction are always consistent. The wire feeding angle of the welding gun is changed following the weld direction. At the end of welding, the wire is fed in place for 2-3 seconds, and then the current begins to decay for about 6 seconds to extinguish the arc. The welding gun stays in place for 20 seconds and the shielding gas is continuously passed through the welding gun to prevent oxidation defects; finally, the gun is lifted back to the home point.

[0024] Compared with the prior art, the present invention has the following beneficial technical effects:

[0025] The base welding of the present invention maintains manual base welding, because base welding has particularly high requirements on the consistency of parts, and is very prone to defects such as burn-through, interlayer, and unfusion. The parts docking requirements themselves have gap errors, and this error affects the base welding of parts and is uncontrollable. The assembly angle of the positioning welding point will affect the base welding. The base welding process is a welding process that is dynamically adjusted and changed in real time.

[0026] The present invention opens an X-shaped groove for the joint to be welded, and uses a manipulator automatic argon arc welding instead of manual argon arc welding. Through reasonable welding fixtures, welding processes, welding parameters, etc., it can effectively reduce the defects such as incomplete penetration, pores, tungsten inclusions, etc. that are easy to produce in thick plate welding, solve the welding deformation problem and the titanium alloy welding oxidation problem, improve the X-ray first-time pass rate and welding efficiency, and improve the processing efficiency and weld appearance quality. Compared with the general pulse automatic argon arc welding parameters, the automatic argon arc welding parameters increase the swing wire width and cycle. This is because the X-shaped groove of the mounting support assembly has a surface width of up to 11 mm at the weld, so the wire needs to be swung to increase the melting amount of the welding wire and avoid weld depression.

[0027] The present invention provides a welding fixture. The mounting support point assembly that has completed the base welding is placed in the welding fixture. The automatic welding program is started. The welding gun is in the welding starting position. After the argon gas is introduced, the automatic argon arc welding with wire filling is started. During welding, the parts are fixed, and the welding gun runs according to a pre-set circular arc track to realize the automatic argon arc welding with wire filling. After each batch of parts has completed the front automatic welding, the back welding fixture is replaced to carry out the back automatic argon arc welding with wire filling of the mounting support point assembly. This not only saves the time of replacing the welding fixture, but also allows a time difference between the front and back welding, which can effectively dissipate heat and prevent more serious welding stress and deformation caused by excessive heat input.

[0028] Titanium alloys are prone to absorbing oxygen and hydrogen during welding, so pre-weld cleaning—pickling and mechanical cleaning—is performed before welding to ensure that the surface of the parts is clean, and argon gas is required to protect the molten pool during welding. Compared with the general pulse automatic argon arc welding parameters, the automatic argon arc welding of the present invention increases the swing wire width and cycle. This is because the X-shaped groove of the mounting support assembly has a maximum width of 11 mm on the surface to be welded, so the wire needs to be swung to increase the melting amount of the welding wire and avoid weld depression.

[0029] The wire-filling automatic argon arc welding uses a robot to automatically feed the wire, and the wire feeding angle needs to be consistent. This can effectively avoid the phenomenon that the welding wire is not completely melted and forms weld defects. Therefore, the coiled wire used by the robot has higher requirements and must be coiled in a tightly compressed spiral shape. When the welding wire is loose and deformed, the deformed section of the welding wire should be cut off before welding to avoid welding defects. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a structural schematic diagram of the installation support point assembly;

[0031] Figure 2 It is a structural schematic diagram of the flange edge;

[0032] Figure 3 It is a schematic diagram of the X groove at the flange edge and the support point welding;

[0033] Figure 4 A welding fixture for the support assembly (front side);

[0034] Figure 5 for Figure 4 The main view;

[0035] Figure 6 A welding fixture for supporting point assembly (reverse side);

[0036] Figure 7 for Figure 6 The main view;

[0037] In the figure, 1. flange edge; 2. mounting opening; 3. feature edge A; 4. feature edge B; 5. feature edge C; 6. support point; 7. X-groove; 8. positioning plate; 9. positioning edge A; 10. positioning edge B; 11. positioning edge C; 12. pre-set groove; 13. argon gas pipe; 14. centering shaft. DETAILED DESCRIPTION

[0038] The present invention is described in detail below in conjunction with specific embodiments and drawings, but the protection scope of the present invention is not limited by the specific embodiments and drawings.

[0039] like Figure 1 As shown, the mounting point assembly of the present invention requires welding the flange edge 1 and the supporting point 6. Figure 2 As shown, one side of the flange edge 1 is a characteristic edge C5, and a mounting opening 2 is provided in the middle of the other side for matching welding with the support point 6. The two sides of the mounting opening 2 are the characteristic edge A3 and the characteristic edge B4 respectively; the welding part of the support point 6 and the mounting opening 2 are both processed and butted to form an X groove 7, as shown in FIG. Figure 3 shown.

[0040] like Figure 4-7The welding device includes a front device and a back device, and the structures of the two are symmetrical with the diameter as the symmetry axis; the front device includes a positioning plate 8, a centering shaft 14 and a positioning assembly, the positioning plate 8 is a circular plate, and a circular pre-set groove 12 is opened in the center of the top surface at the center of the circle, and a support point 6 to be welded is pre-placed; the bottom surface at the center of the circle is fixed to the clamp of the machine tool through the centering shaft 14; the central opening of the centering shaft 14 is installed with an argon gas pipe 13, which is connected to the external argon gas bottle for gas supply; the positioning assembly is protrudingly arranged on the top surface of the positioning plate 8, including a positioning edge A9, a positioning edge B10 and a positioning edge C11, which are respectively limited by the characteristic edges A3, B4 and C5 of the flange edge 1, so that when the front side of the flange edge 1 is placed on the positioning assembly, it is connected to the weld of the pre-placed support point 6 to be welded to form an X-groove 7.

[0041] The welding method of the thick plate mounting support point assembly of the present invention specifically comprises the following steps:

[0042] (1) Cleaning before welding

[0043] For titanium alloy parts, it is necessary to arrange a pickling process before welding. After pickling, mechanical grinding is used to make the front and back sides and end faces of the parts to be welded present a metallic luster. Grinding the end faces and grooves of the joints is allowed to ensure the assembly gap and penetration rate. Wear gloves when welding and turning over titanium alloy parts to prevent grease and other substances from contaminating the parts.

[0044] (2) Manual argon arc welding for positioning welding and base welding

[0045] The tack welding and base welding of the mounting point assembly are carried out by manual argon arc welding. Titanium alloy materials are prone to oxidation and discoloration during welding. It is necessary to pay attention to the argon protection on both the front and back sides of the weld. Pay attention to evenly distribute the welding points during tack welding. After completing the tack welding, manual base welding is carried out. The weld penetration rate during base welding must reach 100% to avoid the situation where the automatic weld seam is not fully penetrated;

[0046] (3) Automatic argon arc welding for wire filling

[0047] To complete the installation support point assembly of the base welding, it is necessary to perform automatic argon arc welding with wire filling on the front and back sides of the weld respectively. The automatic argon arc welding with wire filling is automatically fed by a robot. The coiled welding wire used by the robot is coiled in a compressed spiral shape, and the wire feeding angle is kept consistent. When the spirally coiled welding wire becomes loose and deformed, the deformed wire segment is cut off before welding. The steps of automatic argon arc welding with wire filling are as follows: after the robot moves to the designated point near the weld, it touches the part perpendicular to the direction of the part. After receiving the feedback signal, the welding gun is lifted 2.5mm and the arc is started for 1s. The current increases from 100A to 170A. After staying in place for 1-2s, after burning out a molten pool of suitable size, the wire is swung in place for 2s. The filler wire starts to be fed in 1s later, runs along the welding track and swings horizontally. The tungsten electrode swing distance is 2mm. The welding process tracks the welding height according to the arc voltage feedback. The welding pulse peak welding current is large, the molten pool is large, and more welding wire is added. When it is converted to the base value, the molten pool is relatively small, and the addition of welding wire is reduced to prevent defects such as spatter and interlayer. The wire feeding angle and the weld direction are always consistent. The welding gun wire feeding angle is changed according to the weld direction. At the end of welding, the wire is fed in place for 2-3s, and then the current starts to decay for about 6 seconds to extinguish the arc. The welding gun stays in place for 20 seconds and the welding gun continues to pass the protective gas to prevent oxidation defects. Finally, the gun is lifted back to the home point.

[0048] During welding, the front and back sides of the weld need to be protected by argon gas; a set of welding fixtures is required for automatic welding of the front and back sides respectively. The mounting support point assembly that has completed the base welding is placed in the welding fixture, and automatic welding is started; after each batch of parts has completed the automatic welding of the front side, the back side welding fixture is replaced to carry out automatic argon arc welding of the back side of the mounting support point assembly with wire filling.

[0049] By adopting a reasonable processing method and suitable welding parameters, the automatic argon arc welding method significantly improves the appearance quality of the weld seam compared with manual argon arc welding. The single-machine welding time is 18 minutes / machine, which is lower than the manual welding time of 28 minutes / machine, and the welding time is shortened by 35.7%. The welding deformation control effect of the titanium alloy X-shaped groove assembly is good.

Claims

1. A welding device for thick plate mounting support assembly, characterized in that: The mounting support assembly comprises a flange and a support. One side of the flange is a characteristic edge C, and a mounting opening is provided in the middle of the other side for matching welding with the support. The two sides of the mounting opening are characteristic edge A and characteristic edge B respectively. The welding parts of the support and the mounting opening are processed and butted to form an X groove. The welding device includes a front device and a back device, and the structures of the two are symmetrical with the diameter as the symmetry axis; the front device includes a positioning plate, a centering shaft and a positioning assembly, the positioning plate is a circular plate, and a circular pre-set groove is opened in the center of the top surface at the center of the circle, and the support point to be welded is pre-placed; the bottom surface at the center of the circle is fixed to the clamp of the machine tool through the centering shaft; the central opening of the centering shaft is used to install an argon gas pipe, which is connected to the external argon gas bottle for gas supply; the positioning assembly is protrudingly arranged on the top surface of the positioning plate, including a positioning edge A, a positioning edge B and a positioning edge C, which are respectively limited by the characteristic edges A, B and C of the flange edge, so that when the front side of the flange edge is placed on the positioning assembly, it is connected to the pre-placed weld of the support point to be welded to form an X-groove.

2. A method for welding a thick plate mounting support assembly, characterized in that: The specific steps include: (1) Cleaning before welding For titanium alloy parts, it is necessary to arrange a pickling process before welding. After pickling, mechanical grinding is used to make the front and back sides and end faces of the parts to be welded present a metallic luster. Grinding the end faces and grooves of the joints is allowed to ensure the assembly gap and penetration rate. Wear gloves when welding and turning over titanium alloy parts to prevent grease and other substances from contaminating the parts. (2) Manual argon arc welding for positioning welding and base welding The tack welding and base welding of the mounting point assembly are carried out by manual argon arc welding. Titanium alloy materials are prone to oxidation and discoloration during welding. It is necessary to pay attention to the argon protection on both the front and back sides of the weld. Pay attention to evenly distribute the welding points during tack welding. After completing the tack welding, manual base welding is carried out. The weld penetration rate during base welding must reach 100% to avoid the situation where the automatic weld seam is not fully penetrated; (3) Automatic argon arc welding for wire filling The installation support point assembly that has completed the base welding needs to be automatically argon arc welded with wire filling on the front and back sides of the weld respectively, and argon gas protection is required for the front and back sides of the weld during welding; a set of welding fixtures is required for automatic welding of the front and back sides respectively, and the installation support point assembly that has completed the base welding is placed in the welding fixture, and automatic welding is started; after each batch of parts has completed the automatic welding of the front side, the back side welding fixture is replaced to carry out automatic argon arc welding of the back side of the installation support point assembly with wire filling.

3. The welding method of thick plate mounting support assembly according to claim 2, characterized in that: The wire-filling automatic argon arc welding described in step (3) is automatically fed by a robot, and the coiled welding wire used by the robot is coiled in a compacted spiral shape, and the wire feeding angle remains consistent.

4. The welding method of the thick plate mounting support assembly according to claim 3, characterized in that: When the spirally coiled welding wire becomes loose and deformed, the deformed welding wire section is cut off before welding.

5. The welding method for thick plate mounting support assembly according to claim 2, characterized in that: The steps of the automatic argon arc welding with filler wire described in step (3) are as follows: after the manipulator moves to the designated point near the weld, it touches the part perpendicular to the direction of the part, and after receiving the feedback signal, the welding gun is raised by 2.5 mm and the arc is started for 1 second; the current increases from 100 A to 170 A, and after staying in place for 1-2 seconds, after burning out a molten pool of suitable size, the wire is swung in place for 2 seconds, and the filler wire is fed in after 1 second, running along the welding track and swinging horizontally, and the tungsten electrode swing distance is 2 mm; The welding process tracks the welding height according to the arc voltage feedback. The larger the welding pulse peak welding current is, the larger the melt pool is, and more welding wire is added. When it is converted to the base value, the melt pool is relatively small, which reduces the addition of welding wire and prevents defects such as spatter and interlayer. The wire feeding angle and weld direction are always consistent. The wire feeding angle of the welding gun is changed following the weld direction. At the end of welding, the wire is fed in place for 2-3 seconds, and then the current begins to decay for about 6 seconds to extinguish the arc. The welding gun stays in place for 20 seconds and the shielding gas is continuously passed through the welding gun to prevent oxidation defects; finally, the gun is lifted back to the home point.

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