Special-shaped large-diameter titanium alloy thin-walled pipe assembly welding tool set and welding method

Abstract

The invention provides a special-shaped large-diameter titanium alloy thin-walled pipe assembly welding tool set and a welding method, and belongs to the technical field of aircraft equipment detection.The welding tool set comprises a straight pipe welding tool, a welding dragging cover, a welding auxiliary tool, a positioned welding inspection tool and a heat treatment shape maintaining tool; the welding auxiliary device is used for welding a straight pipe, connecting a welding gun protection welding bead, an auxiliary welding sub-part, an auxiliary positioning welding sub-part and a convex connector, welding inspection and correcting collapse deformation of the welding sub-part on the pipe wall and deformation of a pipe opening in the heat treatment process. In the welding process, the welding tool set is matched for four times of welding, the straight pipe and the bent pipe are welded in the first time, the straight pipe and the bent pipe are welded in a combined mode in the second time, the component is welded in the third time, the convex connector is welded in the fourth time, and finally heat treatment and shape correction are conducted. The welding deformation of the pipe assembly is effectively controlled by formulating reasonable welding parameters, a welding sequence, a proper welding tool, a proper welding piece and a welding wire pre-welding cleaning method, and the problems of welding oxidation discoloration and low percent of pass are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of aircraft equipment detection, and relates to a welding tool set for a special-shaped large-diameter titanium alloy thin-walled pipe assembly and a welding method. Background Art

[0002] Welding deformation is the most challenging problem in the aviation manufacturing industry. When the deformation in the welded structure exceeds the safety limit, parts will be misaligned, which often leads to manufacturing problems such as inaccurate dimensions during assembly. At present, the special-shaped large-diameter thin-walled tube assemblies with titanium alloy as the base material generally include straight tubes, bent tubes, sub-components welded outside the tube wall and convex joints welded at the two ends of the tube mouth. During the welding process, the high heat generated by welding causes the tube wall of the tube assembly to deform and the weld leakage cannot be corrected, resulting in a high scrap rate and a long correction time for the tube assembly. The main reason is that there are a large number of sub-components such as corner pieces, bases, and nozzles in the welded tube assembly that need to be welded together with the tube wall. The sub-components and the tube body are welded with unequal thicknesses. At the same time, the temperature of the welding molten pool is high, the welding current is large, the tube wall is thin, and the heat generated by welding is unevenly distributed. Defects such as weld leakage are easily generated during the welding process, and the deformation and collapse of the tube wall and the sinking of the welded sub-components on the tube assembly will occur. After the weld is cooled, there is a large residual stress that will produce uncontrollable welding deformation, and it cannot be corrected later, resulting in the scrapping of the welded tube assembly. Secondly, due to the lack of suitable argon filling tooling to directly and effectively protect the weld inside the pipe wall, the welded pipe assembly will be rejected due to oxidation discoloration. At the same time, due to the lack of suitable pre-weld cleaning methods, the X-ray inspection pass rate of titanium alloy after welding will be low. Summary of the invention

[0003] In order to solve the above problems, the present invention provides a welding tool set and a welding method for a special-shaped large-diameter titanium alloy thin-walled pipe assembly.

[0004] The technical solution adopted by the present invention is as follows:

[0005] A welding tool set for a special-shaped large-diameter titanium alloy thin-walled pipe assembly comprises a straight pipe welding tool, a welding drag cover, a welding auxiliary tool, a positioning welding inspection tool and a heat treatment shape-preserving tool.

[0006] The straight tube welding tool comprises a base, a copper tube A, a clamping frame, a quick-release latch, a clamping bolt and a clamping block; the base comprises legs on both sides and a beam fixed between the tops of the two legs, the upper surface of the beam is an arc surface, a row of vents is arranged in the middle of the arc surface along the length direction of the beam, the straight tube blank to be welded is surrounded on the beam, and the weld is tightly fitted with the vents; the copper tube A is connected to the vents, and the copper tube A is connected to the argon gas bottle through a hose for argon protection during welding; the clamping frame is a door-shaped frame, with the same structure. Two, two clamping frames are arranged above the beam along the length direction of the beam, and their two ends are detachably fixed to the end faces of the beam by quick-release pins, and the two clamping frames are symmetrically arranged on both sides of the vent, and the top surfaces of the two clamping frames are penetrated by a plurality of clamping bolts along the length direction and threadedly matched; the pressure block is strip-shaped, and there are two of them, which are fixedly connected to the bottom of the clamping bolts on the two clamping frames respectively, and the height of the pressure block is adjusted by turning the clamping bolts to press the straight pipe blank to be welded on the beam to prevent deformation near the weld.

[0007] The welding hood includes a clamp, a hood body, an argon filling hole and an air outlet. The hood body is a closed shell, the upper surface of which is provided with an argon filling hole, and the lower surface is densely covered with a plurality of air outlet holes. A clamp is fixed at one end of the hood body for fixing the welding gun. The argon filling hole is connected to the argon gas bottle through a hose. During welding, the air outlet is closely attached to the weld, and argon gas is introduced to protect the weld to prevent oxidation of the front weld.

[0008] The welding auxiliary tooling includes a shell, an inclined wedge assembly, an expansion flap assembly, a screw assembly, a bearing, a plug, a plug, a copper tube B, a pressure plate, and a knurled high-head screw; the screw assembly includes an internal screw and a cylindrical shell sleeved outside the screw, the screw is a light rod with an external thread at the front end, a bearing is installed at the rear end of the cylindrical shell, and is interference-fitted with the rear end of the screw, a threaded through hole is formed at the center of the front end face of the cylindrical shell, and is matched with the external thread of the screw head, and the rear end of the screw is rotated to adjust the length of the screw head extending out of the cylindrical shell; the shell is cylindrical, and its rear end face is fixedly connected to the front end face of the cylindrical shell in the screw assembly and is The shell body is coaxial, and a through hole is formed in the center of the rear end face of the shell body for the screw to pass through. The side wall of the shell body is evenly distributed with multiple hollows for inserting the petal expansion assembly. The inclined wedge assembly is a cylindrical block, which is placed in the shell body and its rear end is rotatably matched with the front end of the screw rod, so that the inclined wedge assembly can move forward and backward with the screw rod without rotating itself. The side wall of the inclined wedge assembly is circumferentially provided with multiple inclined surfaces inclined toward the front end. The number and position of the inclined surfaces correspond to the hollows on the shell body. A T-shaped slider is fixedly connected to each inclined surface, and the top surface of the T-shaped slider is parallel to the inclined surface. There are a plurality of the petal expansion assemblies with the same structure, which are placed in the hollows of the shell body one by one. The outer surface of the flap assembly is arc-shaped and covered with copper plate. The outer surfaces of all the expanding flap assemblies together form a circular outer contour. The inner surfaces of the expanding flap assemblies are all made of inclined surfaces. The inclined surfaces are provided with T-shaped slide grooves arranged in the front-to-back direction, which slide and cooperate with the T-shaped sliders on the inclined surfaces of the inclined wedge assemblies to prevent the expanding flap assemblies from falling out. The inclined wedge assemblies move forward and backward with the screw rod, and the outer diameter of the expanding flap assemblies increases or decreases under the push-pull action of the inclined wedge assemblies. The outer diameter of the plug is matched with the inner diameter of the straight pipe, which is used to close one side of the pipe opening. A through hole is made in the center, which passes through the outside of the cylindrical shell of the screw rod assembly and slides to enable the plug to adjust its position on the cylindrical shell and the plug is far away. A boss is arranged circumferentially at one end away from the shell, and the shoulder is fitted with the end face of the tube. A plurality of pressure plates are evenly distributed on the circumference of the boss, and a knurled high-head screw is arranged axially on the upper side of the pressure plate. By turning the knurled high-head screw, the pipe mouth is pressed against the plug through the pressure plate. A through hole is formed on the end face of the plug, and a copper tube B is installed in the through hole for introducing argon gas into the tube. The plug is basically the same as the plug structure, except that there is no through hole and copper tube B at the center, and the plug is used to close the pipe mouth on the other side. A pressure plate and a knurled high-head screw are also arranged on the boss of the plug to press the pipe mouth against the plug. The plug cooperates with the plug to form a closed cavity in the tube body. When in use, one end of the shell extends into the welding position of the sub-component in the straight tube, and the rear end of the screw is turned to move the inclined wedge assembly forward, and the expansion petal assembly is pushed to increase its outer diameter until the copper plate fits the inner wall of the tube assembly, thereby achieving the effect of supporting the welding sub-component and conducting away the excess heat of the back weld, and preventing the sub-component from collapsing and deforming after welding.

[0009] The positioning welding inspection tooling includes a base plate, a straight pipe support assembly, a sub-assembly positioning assembly and a pipe nozzle positioning assembly; a straight pipe support assembly is fixedly connected to the middle of the base plate, which includes a plurality of vertically placed support plates, the upper end surfaces of the support plates are arc-shaped, and are used to horizontally place and support the straight pipes in the welded pipe assembly; there are two pipe nozzle positioning assemblies, which are fixedly connected to the two ends of the base plate respectively, and the upper end of the pipe nozzle positioning assembly is a disc-shaped pipe nozzle positioner, and the end surface of the pipe nozzle positioner on one side is perpendicular to the horizontal plane, which is used to position the pipe nozzle or position and support the convex joint at the pipe nozzle on the straight pipe side of the pipe assembly, and the support position is adjustable. The end face of the nozzle locator on the other side is at a certain angle to the horizontal plane, and is used to position and support the other male joint at the nozzle on the elbow side of the pipe assembly or to position the nozzle at the other end. The support position is also adjustable. After the two male joints are positioned with the nozzles, they are clamped by fixing the positions with latches. The number of sub-component positioning components corresponds to the number of sub-components on the pipe assembly. The lower end is fixedly mounted on the bottom plate, and the position is determined by the position of the sub-component on the pipe assembly. A sub-component locator is provided at the upper end. The end of the sub-component locator is connected to the sub-component, and the sub-component is positioned and pressed against the outer wall of the pipe assembly. The support position of the sub-component locator is adjustable, and it is fixed by latches after being adjusted into place. The positioning welding inspection tool is used to position and weld sub-components and male joints, and is also used for verification after welding and repair.

[0010] The overall shape of the heat treatment retaining tooling is set according to the inner shape of the pipe assembly, and is used to correct the collapse and deformation of the welding sub-components on the pipe wall and the deformation of the pipe mouth during heat treatment. The heat treatment retaining tooling is an assembled structure, including a straight pipe part and a bent pipe part. The bent pipe part is divided into a middle plate-shaped block along the axis, and the two sides are respectively divided into two bent pipe blocks along the circumferential direction. After assembly, they are fixed by detachable bolts.

[0011] The present invention also provides a welding method for a special-shaped large-diameter titanium alloy thin-walled pipe assembly, which is implemented based on the above-mentioned welding tooling assembly. The welding method comprises the following steps:

[0012] Step 1, prepare the plate-shaped straight tube billet and two semi-arc bent tube billets that have been bent, perform repairs and pre-welding cleaning in turn, perform positioning welding on the straight tube billet on the straight tube welding tooling, and preliminarily fix the two semi-arc bent tube billets by positioning welding.

[0013] Step 2, the first welding, complete the straight pipe welding and the bent pipe welding respectively:

[0014] Use straight pipe welding tooling for straight pipe welding, and use welding drag cover to complete bent pipe welding. Welding parameters: when welding materials of different thicknesses, calculate according to thin plates, welding current intensity 25-40A, welding wire material is TC4 with a diameter of 1.0mm, tungsten electrode diameter 1.5mm, arc voltage 8-13V, argon gas flow rate on the front side of the weld is 11-15L / min, and argon gas flow rate on the back side of the weld is 4-6L / min. After welding is completed, gas supply continues for 40 seconds.

[0015] Step 3: Check the welding quality of straight pipes and bent pipes after welding, and then perform repair, pre-welding cleaning and positioning welding in sequence.

[0016] Step 4, the second welding, use the welding hood to weld the straight pipe and the bent pipe together, and the welding parameters refer to step 2.

[0017] Step 5, use the positioning welding inspection tool to inspect the straight pipe and elbow assembly after welding, and then perform X-ray inspection, pickling, fluorescence inspection, and repair in sequence. Among them, X-ray inspection is used to inspect the internal quality of the weld, and fluorescence inspection is used for the surface quality of the weld.

[0018] Step 6, use the positioning welding inspection tool to position the sub-component on the straight tube elbow assembly for positioning welding. After positioning welding, remove the straight tube elbow assembly from the positioning welding inspection tool, use the welding drag cover and the welding auxiliary tool to perform the third welding, and weld the sub-component to the straight tube elbow assembly. Refer to step 2 for welding parameters.

[0019] Step 7, use the positioning welding inspection tool to weld the pipe assembly, and then perform X-ray inspection, pickling, fluorescence inspection and repair in sequence. After the repair, use the positioning welding inspection tool to inspect.

[0020] Step 8, use the tack welding inspection tool to position the male joint at the pipe ends of the straight pipe elbow assembly and perform tack welding. After tack welding, remove the pipe assembly from the tack welding inspection tool, use the welding hood for plug welding, and weld the male joint to the straight pipe elbow assembly. Refer to step 2 for welding parameters.

[0021] Step 9: Use the positioning welding inspection tool to perform welding inspection and then perform X-ray inspection.

[0022] Step 10: Use heat treatment tooling to complete the heat treatment of the tube assembly:

[0023] The disassembled heat treatment shape-preserving tooling is assembled and fixed in the pipe assembly, and fits with the inner wall of the pipe assembly. A vacuum heat treatment method is adopted, the heat treatment atmosphere is argon, the heat treatment temperature is 480℃~650℃, the insulation time is 60min~360min, and the furnace is cooled to below 100℃ and then air-cooled out of the furnace.

[0024] Step 11, perform final inspection using the tack welding inspection tool.

[0025] The beneficial effects of the present invention are:

[0026] The present invention ensures appropriate welding heat input and controls welding deformation by adopting reasonable welding process parameters. Positioning welding and inspection tooling are used to perform positioning welding of sub-components and ensure the position of welded parts. After the parts are welded or the welded parts are repaired, they are all placed on this tooling for verification. Straight pipe welding tooling is used to perform positioning welding and welding of straight pipes. This tooling can effectively control the welding deformation and oxidation discoloration of straight pipes. A welding drag cover is used to weld sub-components, mainly to prevent oxidation of the front weld. When welding sub-components, welding auxiliary tooling is used to support the welding sub-components and guide away excess heat of the back weld to prevent the sub-components from collapsing and deforming after welding, and to prevent oxidation of the back weld. A heat treatment shape-keeping tooling is used to perform overall heat treatment correction of the welded pipe assembly, and reasonable heat treatment process parameters are formulated at the same time. The expansion coefficient of steel is greater than the expansion coefficient of titanium alloy, and the collapse deformation of the welded sub-components is further corrected by thermal expansion. By formulating a reasonable manufacturing process flow of welded pipe assemblies, the welding deformation generated by welding special-shaped large-diameter titanium alloy thin-walled pipe assemblies can be dispersed. By formulating a pre-welding cleaning method for welded parts and a pre-welding cleaning method for welding wires, defects such as pores in welds caused by contamination of welded parts and welding wires can be effectively reduced, thereby effectively improving the qualified rate of X-ray detection. The present invention effectively controls the welding deformation of special-shaped large-diameter titanium alloy thin-walled pipe assemblies by formulating reasonable welding parameters and welding sequence, suitable welding tools and welded parts, and a pre-welding cleaning method for welding wires, and solves the problems of welding oxidation discoloration and low qualified rate of X-ray detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of a typical special-shaped large-diameter titanium alloy thin-walled welded pipe assembly.

[0028] Figure 2 Schematic diagram of straight pipe welding tooling, where (a) is the main view and (b) is the top view.

[0029] Figure 3 This is the axonometric view of the straight pipe welding tooling.

[0030] Figure 4 Schematic diagram of a welding hood, where (a) is the main view, (b) is the side view, and (c) is the axonometric view.

[0031] Figure 5 This is a schematic diagram of welding auxiliary tooling.

[0032] Figure 6 Schematic diagram of positioning welding inspection work

[0033] Figure 7 Schematic diagram of heat treatment shape-preserving tooling.

[0034] In the figure: 1 straight pipe; 2 bent pipe; 3 bracket; 4 convex joint; 5 base; 6 copper pipe A; 7 clamping frame; 8 quick-release pin; 9 clamping bolt; 10 clamping block; 11 clamp; 12 cover body; 13 argon filling hole; 14 air outlet hole; 15 shell; 16 wedge assembly; 17 petal assembly; 18 screw assembly; 19 bearing; 20 plug; 21 plug; 22 copper pipe B; 23 pressure plate; 24 knurled high head screw; 25 bottom plate; 26 straight pipe support assembly; 27 sub-component positioning assembly; 28 pipe mouth positioning assembly; 29 straight pipe part; 30 plate-like block; 31 bent pipe block. DETAILED DESCRIPTION

[0035] The technical solution of the present invention is described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments improved or adjusted by ordinary technicians in this field based on the embodiments of the present invention belong to the protection scope of the present invention.

[0036] This embodiment uses Figure 1 Taking the typical special-shaped large-diameter titanium alloy thin-walled welded pipe assembly shown in the figure as an example, the pipe assembly includes a straight pipe 1, a bent pipe 2, a sub-component and a convex joint 4, wherein one end of the straight pipe 1 is connected to the convex joint 4, and the other end is connected to the bent pipe 2, and the other end of the bent pipe 2 is connected to another convex joint 4, and multiple groups of sub-components are welded on the bent pipe 2. The sub-component in the pipe assembly is a double-ear plate type bracket 3, and the welding base material is TC4-annealed. The specification of the straight pipe 1 is 0.8mm, the specification of the bent pipe 2 is 0.8mm, the specification of the bracket 3 is 1.4mm, and the specification of the convex joint 4 is 2mm.

[0037] On the one hand, this embodiment provides a welding tooling group for a special-shaped large-diameter titanium alloy thin-walled pipe assembly, wherein the welding tooling group includes a straight pipe welding tooling, a welding drag cover, a welding auxiliary tooling, a positioning welding inspection tooling and a heat treatment shape-preserving tooling.

[0038] like Figure 2 and Figure 3As shown, the straight tube welding tool comprises a base 5, a copper tube A 6, a clamping frame 7, a quick-release pin 8, a clamping bolt 9 and a clamping block 10; the base 5 comprises legs on both sides and a beam fixed between the tops of the two legs, the upper surface of the beam is an arc surface, and a row of vents is arranged in the middle of the arc surface along the length direction of the beam, the straight tube blank to be welded surrounds the beam, and the weld is closely fitted with the vents; the copper tube A 6 is connected to the vents, and the copper tube A 6 is connected to an argon gas bottle through a hose for argon protection during welding; the clamping frame 7 is a door-type frame, and two of the same structure are provided. The two clamping frames 7 are arranged above the beam along the length direction of the beam, and their two ends are detachably fixed to the end faces of the two ends of the beam through quick-release pins 8, and the two clamping frames 7 are symmetrically arranged on both sides of the vent, and the top surfaces of the two clamping frames 7 are penetrated by a plurality of clamping bolts 9 along the length direction, and threadedly matched; the pressing block 10 is strip-shaped, and two are provided, which are respectively fixedly connected to the bottom of the clamping bolts 9 on the two clamping frames 7, and the height of the pressing block 10 is adjusted by turning the clamping bolts 9 to press the straight pipe billet to be welded on the beam to prevent deformation near the weld.

[0039] like Figure 4 The welding hood shown in the figure comprises a clamp 11, a hood body 12, an argon filling hole 13 and an air outlet 14. The hood body 12 is a closed shell, the upper surface of which is provided with an argon filling hole 13, and the lower surface is densely covered with a plurality of air outlets 14. A clamp 11 is fixed at one end of the hood body 12 for fixing the welding gun. The argon filling hole 13 is connected to the argon gas bottle through a hose. During welding, the air outlet 14 is closely fitted to the weld, and argon gas is introduced to protect the weld to prevent oxidation of the front weld.

[0040] like Figure 5As shown, the main body material of the welding auxiliary tooling is Q235 steel, including a shell 15, an inclined wedge assembly 16, an expansion flap assembly 17, a screw assembly 18, a bearing 19, a plug 20, a plug 21, a copper tube B 22, a pressure plate 23, and a knurled high head screw 24; the screw assembly 18 includes an internal screw and a cylindrical shell sleeved outside the screw, the screw is a light rod with an external thread at the front end, a bearing 19 is installed at the rear end of the cylindrical shell, which is interference fit with the rear part of the screw, a threaded through hole is formed in the center of the front end face of the cylindrical shell, which cooperates with the external thread of the screw head, and the length of the screw head extending out of the cylindrical shell is adjusted by rotating the rear end of the screw; the shell 15 is cylindrical, and its rear end face is fixedly connected and coaxial with the front end face of the cylindrical shell in the screw assembly 18, and the center of the rear end face of the shell 15 is formed with a through hole The side wall of the housing 15 is evenly distributed with three square hollows for inserting the petal expansion assembly 17; the wedge assembly 16 is a cylindrical block, which is placed in the housing 15 and its rear end is rotatably matched with the front end of the screw, so that the wedge assembly 16 can move forward and backward with the screw without rotating itself. The side wall of the wedge assembly 16 is formed with three inclined surfaces inclined toward the front end along the circumferential direction, and the positions of the inclined surfaces correspond to the square hollows on the housing 15. A T-shaped slider is fixedly connected to each inclined surface, and the top surface of the T-shaped slider is parallel to the inclined surface; the petal expansion assembly 17 has a common structure The three same ones have a square outer contour and are placed one by one in the square hollow of the shell 15. The outer surface of the expansion petal component 17 is arc-shaped and covered with a copper plate with a thickness of 5 mm. The outer surfaces of all the expansion petal components 17 together form a circular outer contour. The inner surfaces of the expansion petal components 17 are all made of inclined surfaces, and the inclined surfaces are provided with T-shaped slide grooves arranged along the front-to-back direction, which slide and cooperate with the T-shaped sliders on the inclined surfaces of the inclined wedge components 16 and prevent the expansion petal components 17 from falling out. The inclined wedge components 16 move forward and backward with the screw rod, and the outer diameter of the expansion petal components 17 increases or decreases under the push-pull action of the inclined wedge components 16; The outer diameter of the plug 20 is matched with the inner diameter of the straight tube 1, and is used to close one side of the pipe opening. A through hole is formed in the center, which is passed through the cylindrical shell of the screw assembly 18 and slidably matched, so that the plug 20 can adjust its position on the cylindrical shell. A boss is circumferentially arranged at one end of the plug 20 away from the shell 15, and the shoulder fits with the end face of the pipe. A plurality of pressing plates 23 are evenly distributed along the circumference of the boss. A knurled high-head screw 24 is axially arranged on the pressing plate 23. The knurled high-head screw 24 is turned to press the pipe opening onto the plug 20 through the pressing plate 23. A through hole is formed on the end face of the plug 20, and a copper tube B is installed in the through hole. 22, used to introduce argon into the tube; the plug 21 is basically the same in structure as the plug 20, except that no through hole and copper tube are provided at the center, the plug 21 is used to close the tube opening on the other side, and a pressure plate 23 and a knurled high-head screw 24 are also provided on the boss of the plug 21, which are used to press the tube opening onto the plug 21; the plug 20 cooperates with the plug 21 to form a closed cavity in the tube body.When in use, one end of the shell 15 extends into the welding position of the bracket 3 in the straight tube 1, and the rear end of the screw is turned to move the inclined wedge assembly 16 forward, pushing the expansion petal assembly 17 to increase its outer diameter until the copper plate fits the inner wall of the tube assembly, thereby achieving the effect of supporting the welded bracket 3 and conducting away the excess heat of the back weld, preventing the bracket 3 from collapsing and deforming after welding.

[0041] like Figure 6 As shown, the positioning welding inspection tooling includes a base plate 25, a straight pipe support assembly 26, a sub-assembly positioning assembly 27 and a pipe nozzle positioning assembly 28; the middle part of the base plate 25 is fixedly connected with a straight pipe support assembly 26, which includes a plurality of vertically placed support plates, the upper end surfaces of the support plates are arc-shaped, and are used to horizontally place and support the straight pipe 1 in the welded pipe assembly; there are two pipe nozzle positioning assemblies 28, which are fixedly connected to the two ends of the base plate 25 respectively, and the upper end of the pipe nozzle positioning assembly 28 is a disc-shaped pipe nozzle positioner, and the end surface of the pipe nozzle positioner on one side is perpendicular to the horizontal plane, which is used to position and support the convex joint 4 at the pipe nozzle on the straight pipe side of the pipe assembly. The support position is adjustable, and the end face of the pipe mouth locator on the other side is at a certain angle to the horizontal plane, which is used to position and support the other male joint 4 at the pipe mouth on the bend side of the pipe assembly. The support position is also adjustable. After the two male joints 4 are positioned with the pipe mouth, they are clamped by fixing the position with a latch. The number of sub-component positioning components 27 corresponds to the number of brackets 3 on the pipe assembly. The lower end is fixedly mounted on the bottom plate 25, and the position is determined according to the position of the bracket 3 on the pipe assembly. A sub-component locator is set at the upper end, and the end of the sub-component locator is connected to the bracket 3, and the bracket 3 is positioned and pressed against the outer wall of the pipe assembly. The support position of the sub-component locator is adjustable, and it is fixed by a latch after being adjusted into place. The positioning welding inspection tool is used for positioning welding brackets 3 and male joints 4, and is also used for verification after welding and repair.

[0042] like Figure 7 As shown, the overall shape of the heat treatment retaining fixture is set according to the inner shape of the pipe assembly, and the main material is Q235 steel. It is used to correct the collapse and deformation of the welding sub-components on the pipe wall and the deformation of the pipe mouth during heat treatment. The heat treatment retaining fixture is an assembled structure, including a straight pipe part 29 and a bent pipe part. The bent pipe part is divided into a middle plate-shaped block 30 along the axis, and the two sides are respectively divided into two bent pipe blocks 31 along the circumferential direction. After assembly, they are fixed by detachable bolts.

[0043] The present invention also provides a welding method for a special-shaped large-diameter titanium alloy thin-walled pipe assembly, which is implemented based on the above-mentioned welding tooling assembly. The welding method comprises the following steps:

[0044] Step 1: Prepare the plate-shaped straight tube blank and two semi-arc bent tube blanks that have been bent, and perform repair and pre-welding cleaning in turn:

[0045] The repair requirements are: the welding edge must be repaired and smooth, and cracks, cracks, indentations, burrs and other defects are not allowed. The roughness Ra value is not greater than 3.2μm, the gap value of the butt joint is controlled at 0~0.1mm, and the gap value of the lap joint is controlled at 0~0.5mm.

[0046] Pre-welding cleaning includes pre-welding cleaning of welded parts and pre-welding cleaning of welding wire:

[0047] Cleaning method for welded parts before welding: Step 1, pickling; Step 2, use a white fine cloth dipped in acetone solution to repeatedly scrub the welding area for 3 minutes; Step 3, use a wire brush to grind the welding area until it has a metallic luster, and the grinding area size is 20 to 30 mm on one side; Step 4, use a scraper to scrape the vertical edge of the parent material in the welding area until it has a metallic luster; Step 5, use a white fine cloth dipped in acetone solution to repeatedly scrub the welding area for 3 minutes; Step 6, use acetone to scrub the area to be welded again before welding.

[0048] Welding wire cleaning method before welding: the first step is pickling; the second step is to use a white fine flat cloth dipped in acetone solution to repeatedly scrub the welding wire; the third step is to use a scouring pad to repeatedly polish the welding wire until it has a metallic luster; the fourth step is to use acetone to scrub the welding wire again before welding. Cleaning according to the cleaning methods for welded parts and welding wires can greatly improve the pass rate of radiographic inspection of titanium alloy welding components.

[0049] On the straight pipe welding tool, the straight pipe billet after the bending is completed is wrapped around the crossbeam, the straight pipe billet is tack welded, and the two semi-arc bent pipe billets are initially fixed by tack welding; the spacing of the tack welding points is 20 to 80 mm, and the length does not exceed 4 mm. After tack welding, the misalignment of the butt joint does not exceed 10% of the thickness of the thin plate in the joint.

[0050] Step 2, the first welding, complete the straight pipe 1 welding and the bent pipe 2 welding respectively:

[0051] Use the straight pipe welding tool to weld the straight pipe 1, fit the weld of the straight pipe billet after positioning welding tightly with the vent hole, fix two clamping frames 7 at both ends of the beam, turn the clamping bolts 9 to adjust the height of the clamping block 10, and clamp the straight pipe billet on the beam. During welding, introduce argon gas through the copper pipe A 6.

[0052] The welding of the bent pipe 2 is completed by using a welding hood, the welding gun is fixed in the clamp 11, and the bottom surface of the welding hood with the air outlet 14 is attached to the weld bead. During welding, argon gas is introduced into the argon filling hole 13.

[0053] Welding parameters: When welding materials of different thicknesses, calculate based on thin plates, welding current intensity 25-40A, welding wire material TC4 with a diameter of 1.0mm, tungsten electrode diameter 1.5mm, arc voltage 8-13V, argon flow rate on the front side of the weld is 11-15L / min, argon flow rate on the back side of the weld is 4-6L / min, and gas supply is continued for 40 seconds after welding is completed.

[0054] Step 3, check the welding quality of the straight pipe 1 and the bent pipe 2 after welding, and then perform repair, pre-welding cleaning and positioning welding in sequence to preliminarily fix the straight pipe 1 and the bent pipe 2. The method and requirements refer to step 1.

[0055] Step 4, the second welding, use the welding hood to weld the straight pipe 1 and the bent pipe 2 together, and the welding parameters refer to step 2.

[0056] Step 5, use the positioning welding inspection tool to inspect the straight pipe and elbow assembly after welding, and then perform X-ray inspection, pickling, fluorescence inspection, and repair in sequence. Among them, X-ray inspection is used to inspect the internal quality of the weld, and fluorescence inspection is used for the surface quality of the weld. Other operation requirements refer to step 1.

[0057] Step 6, use the positioning welding inspection tool to position the bracket 3 on the straight tube bend assembly for positioning welding: place the straight tube bend assembly on the straight tube support assembly 26 of the positioning welding inspection tool, adjust the position of the pipe mouth positioning assembly 28 and the angle and position of the straight tube bend assembly, position and fix the straight tube bend assembly, connect the bracket 3 to the sub-component locator at the end of the sub-component positioning assembly 27, use the sub-component positioning assembly 27 to fix it on the outer wall of the straight tube bend assembly, perform positioning welding on the bracket, and remove the straight tube bend assembly after positioning welding.

[0058] Insert one end of the shell 15 of the welding auxiliary tooling into the welding position of the bracket 3 in the straight tube elbow assembly, turn the screw to push the inclined wedge assembly 16 forward, and make the expansion flap assembly 17 expand outward and support the inner wall of the bracket 3 welding position through the inclined surface, press the plug 20 and the plug 21 on both ends of the pipe, and introduce argon gas through the copper tube B 22; use the welding hood and the welding auxiliary tooling to perform the third welding, weld the bracket 3 to the straight tube elbow assembly, and refer to step 2 for welding parameters.

[0059] Step 7, use the positioning welding inspection tool to weld the pipe assembly, and then perform X-ray inspection, pickling, fluorescence inspection and repair in sequence. After the repair, use the positioning welding inspection tool to inspect.

[0060] Step 8, place the pipe assembly on the positioning welding inspection tool again, use the pipe mouth positioning assembly 28 to position the male joint 4 at the pipe mouths at both ends of the straight pipe elbow assembly and perform positioning welding. After positioning welding, remove the pipe assembly, use the welding drag cover for plug welding, and weld the male joint 4 to the straight pipe elbow assembly. Refer to step 2 for welding parameters.

[0061] Step 9: Use the positioning welding inspection tool to perform welding inspection and then perform X-ray inspection.

[0062] Step 10: Use heat treatment tooling to complete the heat treatment of the tube assembly:

[0063] After the pipe assembly is naturally aged for 48 hours after welding, the disassembled heat treatment shape-preserving tooling is assembled and fixed in the pipe assembly, and fits with the inner wall of the pipe assembly. The vacuum heat treatment method is adopted, the heat treatment atmosphere is argon, the heat treatment temperature is 480℃~650℃, the insulation time is 60min~360min, and it is cooled to below 100℃ with the furnace and air-cooled out of the furnace.

[0064] Step 11, perform final inspection using the tack welding inspection tool.

[0065] The above-described embodiments merely express the implementation methods of the present invention, but they should not be understood as limiting the scope of the present invention. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A welding tooling set for a special-shaped large-diameter titanium alloy thin-walled pipe assembly, characterized in that: The welding tool set includes a straight pipe welding tool, a welding drag cover, a welding auxiliary tool, a positioning welding inspection tool and a heat treatment shape-preserving tool; The straight pipe welding tool is provided with a row of vent holes, which are used to press the straight pipe blank weld bead onto the vent holes to protect the weld bead and prevent deformation; The welding hood is fixedly connected to the welding gun and attached to the weld bead, and is used to introduce argon gas into the weld bead for weld bead protection; The welding auxiliary tooling is used to extend into the interior of the pipe assembly and support the inner wall of the pipe assembly welding sub-component to prevent collapse and deformation after welding; The positioning welding inspection tool is used to position the sub-component or the male joint (4) on the pipe assembly to realize positioning welding, and is also used for inspection after welding and repair.

2. The welding tooling set for a special-shaped large-diameter titanium alloy thin-walled pipe assembly according to claim 1 is characterized in that: The straight tube welding tool comprises a base (5), a copper tube A (6), a clamping frame (7), a clamping bolt (9) and a clamping block (10); the base (5) comprises supporting legs on both sides and a crossbeam fixed between the tops of the two supporting legs, the upper surface of the crossbeam is an arc surface, and a row of vents are arranged in the middle of the arc surface along the length direction of the crossbeam, the straight tube blank to be welded is surrounded on the crossbeam, and the weld is tightly fitted with the vents; the copper tube A (6) is connected to the vents, and the copper tube A (6) is connected to the argon gas bottle through a hose for argon protection during welding; the clamping frame (7) is a door-shaped frame, with a total of Two clamping frames (7) with the same structure are arranged above the cross beam along the length direction of the cross beam, and their two ends are detachably fixed on the end faces of the cross beam, and the two clamping frames (7) are symmetrically arranged on both sides of the vent hole. A plurality of clamping bolts (9) pass through the top surfaces of the two clamping frames (7) along the length direction and are threadedly matched; the pressure block (10) is strip-shaped, and there are two of them, which are fixedly connected to the bottom of the clamping bolts (9) on the two clamping frames (7), and the height of the pressure block (10) is adjusted by turning the clamping bolts (9) to press the straight pipe blank to be welded on the cross beam.

3. The welding tooling set for a special-shaped large-diameter titanium alloy thin-walled pipe assembly according to claim 1 is characterized in that: The welding hood comprises a clamp (11), a hood body (12), an argon filling hole (13) and an air outlet hole (14); the hood body (12) is a closed shell (15), the upper surface of which is provided with an argon filling hole (13), and the lower surface is densely covered with a plurality of air outlet holes (14); a clamp (11) is fixed to one end of the hood body (12) for fixing a welding gun; the argon filling hole (13) is connected to an argon gas bottle through a hose; during welding, the air outlet hole (14) is closely fitted to the weld, and argon gas is introduced to protect the weld.

4. The welding tooling set for a special-shaped large-diameter titanium alloy thin-walled pipe assembly according to claim 1 is characterized in that: The welding auxiliary tooling comprises a shell (15), an inclined wedge assembly (16), an expansion flap assembly (17), a screw assembly (18), a bearing (19), a plug (20), a plug (21), a copper tube B (22), a pressure plate (23), and a knurled high-head screw (24); the screw assembly (18) comprises an internal screw and a cylindrical shell (15) sleeved outside the screw, the screw is a smooth rod with an external thread at the front end, a bearing (19) is installed at the rear end of the cylindrical shell (15), which is interference-fitted with the rear part of the screw, a threaded through hole is formed at the center of the front end face of the cylindrical shell (15), which is matched with the external thread of the screw head, and the length of the screw head extending out of the cylindrical shell (15) is adjusted by rotating the rear end of the screw; the shell (15) is a cylindrical The rear end face of the housing (15) is fixedly connected and coaxial with the front end face of the columnar housing (15) in the screw assembly (18). A through hole is formed in the center of the rear end face of the housing (15) for the screw to pass through. A plurality of hollows are evenly distributed on the side wall of the housing (15) for inserting the petal expansion assembly (17). The inclined wedge assembly (16) is a cylindrical block, which is placed in the housing (15) and its rear end is rotatably matched with the front end of the screw, so that the inclined wedge assembly (16) can move forward and backward with the screw without rotating itself. The side wall of the inclined wedge assembly (16) is formed with a plurality of inclined surfaces inclined toward the front end along the circumferential direction. The number and position of the inclined surfaces correspond to the hollows on the housing (15). A T-shaped slider is fixedly connected to each inclined surface, and the top surface of the T-shaped slider is parallel to the inclined surface. 17) have a total of multiple components with the same structure, which are placed one by one in the hollow part of the shell (15). The outer surface of the expansion flap component (17) is arc-shaped, and the outer surfaces of all the expansion flap components (17) together form a circular outer contour. The inner surface of the expansion flap component (17) is made of an inclined surface, and a T-shaped slide groove arranged along the front-to-back direction is made on the inclined surface to slide with the T-shaped slider on the inclined surface of the inclined wedge component (16) and prevent the expansion flap component (17) from falling out. The expansion flap component (17) increases or decreases its outer diameter under the push-pull action of the inclined wedge component (16); the outer diameter of the plug (20) is matched with the inner diameter of the straight pipe (1) and is used to close one side of the pipe opening. The center is made of a through hole, which passes through the outside of the columnar shell (15) of the screw assembly (18) and slides to fit. The plug (20) is away from A boss is provided at one end of the shell (15) along the circumference, and the shoulder is fitted with the end face of the tube. A plurality of pressure plates (23) are evenly distributed along the circumference of the boss. A knurled high-head screw (24) is axially provided on the pressure plate (23). The knurled high-head screw (24) is turned to press the tube mouth onto the plug (20) through the pressure plate (23). A through hole is formed on the end face of the plug (20), and a copper tube B (22) is installed in the through hole for introducing argon gas into the tube. The plug (21) is basically the same in structure as the plug (20), except that no through hole and no copper tube are provided at the center. The plug (21) is used to close the tube mouth on the other side. A pressure plate (23) and a knurled high-head screw (24) are also provided on the boss of the plug (21) for pressing the tube mouth onto the plug (21).

5. The welding tooling set for a special-shaped large-diameter titanium alloy thin-walled pipe assembly according to claim 1 is characterized in that: The positioning welding inspection tool comprises a base plate (25), a straight pipe support assembly (26), a sub-assembly positioning assembly (27) and a pipe nozzle positioning assembly (28); the middle part of the base plate (25) is fixedly connected with a straight pipe support assembly (26), the upper end surface of which is arc-shaped and is used to horizontally place and support the straight pipe (1) in the welded pipe assembly; there are two pipe nozzle positioning assemblies (28), which are fixedly connected to the two ends of the base plate (25) respectively, and the upper end of the pipe nozzle positioning assembly (28) is a disc-shaped pipe nozzle positioner, the position and angle of which are set according to the pipe nozzles at both ends of the pipe assembly, and is used to position the pipe nozzle or position and support the convex joint (4) at the pipe nozzle; the number of the sub-assembly positioning assemblies (27) corresponds to the number of sub-assemblies on the pipe assembly, the lower end of which is fixedly installed on the base plate (25), the position is determined according to the position of the sub-assembly on the pipe assembly, and the upper end is provided with a sub-assembly positioner, the end of the sub-assembly positioner is connected to the sub-assembly, and the sub-assembly is positioned and pressed against the outer wall of the pipe assembly.

6. The welding tooling set for a special-shaped large-diameter titanium alloy thin-walled pipe assembly according to claim 1, characterized in that: The overall shape of the heat treatment shape retaining tooling is set according to the inner shape of the pipe assembly. The heat treatment shape retaining tooling is an assembled structure, including a straight pipe part (29) and a bent pipe part. The bent pipe part is divided into a middle plate-shaped block (30) along the axis, and the two sides are respectively divided into two bent pipe blocks (31) along the circumferential direction. After assembly, they are fixed by detachable bolts.

7. A welding method for a special-shaped large-diameter titanium alloy thin-walled pipe assembly, implemented based on the welding tooling assembly according to any one of claims 1 to 6, characterized in that: The welding method comprises the following steps: Step 1, prepare the plate-shaped straight tube billet and two semi-arc bent tube billets that have been bent, perform repair and pre-welding cleaning in sequence, perform tack welding on the straight tube billet on the straight tube welding tool, and preliminarily fix the two semi-arc bent tube billets by tack welding; Step 2, the first welding, using a straight pipe welding tool to weld the straight pipe (1), and using a welding hood to complete the welding of the bent pipe (2); Step 3, check the welding quality of the straight pipe (1) and the bent pipe (2) after welding, and then perform repair, pre-welding cleaning and tack welding in sequence; Step 4, a second welding, using a welding hood to weld the straight pipe (1) and the bent pipe (2) together; Step 5, use the positioning welding inspection tool to inspect the straight pipe and elbow assembly after welding, and then perform X-ray inspection, pickling, fluorescence inspection, and repair in sequence, wherein X-ray inspection is used to inspect the internal quality of the weld, and fluorescence inspection is used for the surface quality of the weld; Step 6, using the tack welding inspection tool to position the sub-component on the straight pipe elbow assembly for tack welding, after tack welding, remove the straight pipe elbow assembly from the tack welding inspection tool, use the welding drag cover and the welding auxiliary tool to perform the third welding, and weld the sub-component on the straight pipe elbow assembly; Step 7, use the tack welding inspection tool to perform welding inspection on the pipe assembly, and then perform X-ray inspection, pickling, fluorescence inspection and repair in sequence, and after repair, perform inspection using the tack welding inspection tool; Step 8, using a tack welding inspection tool to position the male joint (4) at the pipe openings at both ends of the straight pipe elbow assembly and perform tack welding, after tack welding, remove the pipe assembly from the tack welding inspection tool, use a welding hood to perform plug welding, and weld the male joint (4) to the straight pipe elbow assembly; Step 9, using the tack welding inspection tool to perform welding inspection and then perform X-ray inspection; Step 10, using a heat treatment shape-preserving tool to complete the heat treatment of the tube assembly; Step 11, perform final inspection using the tack welding inspection tool.

8. The welding method of a special-shaped large-diameter titanium alloy thin-walled pipe assembly according to claim 7 is characterized in that: The welding parameters in step 2, step 4, step 6 and step 8 are as follows: when welding materials of different thicknesses, the combination is calculated as thin plate, the welding current intensity is 25-40A, the welding wire material is TC4 with a diameter of 1.0mm, the tungsten electrode diameter is 1.5mm, the arc voltage is 8-13V, the argon flow rate on the front side of the weld is 11-15L / min, the argon flow rate on the back side of the weld is 4-6L / min, and the gas supply is continued for 40 seconds after welding is completed.

9. The welding method of a special-shaped large-diameter titanium alloy thin-walled pipe assembly according to claim 7, characterized in that: In the step 8, a vacuum heat treatment method is adopted, the heat treatment atmosphere is argon, the heat treatment temperature is 480°C to 650°C, the insulation time is 60min to 360min, and the furnace is cooled to below 100°C and then air-cooled.

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