Welding process for single-side welding and double-side forming

Abstract

The invention provides a welding process for one-side welding and double-side forming. The welding process comprises the step that a connector on one side of a barrel corresponds to a connecting pipe at one end of a heat exchange assembly. And a welding device is used for conducting spot welding positioning on the barrel connector and the connecting pipe of the heat exchange assembly. Welding devices are respectively fixed on the outer walls of mutually symmetrical nozzles in a plurality of directions on one side of the barrel, and the plurality of welding devices are controlled to work at the same time; wherein the pipe nozzle is arranged on a connector on the outer wall of the cylinder body. And after the welding is completed, the multiple welding devices are disassembled and installed on other non-welded pipe nozzles again, and the welding steps are repeated till all the connectors on one side of the barrel are welded. And the cylinder and the heat exchange assembly are turned over, the spot welding and welding steps are repeated, and welding of the other side of the cylinder and the other side of the heat exchange assembly is completed. Automatic TIG welding of the horizontally-fixed inner wall of the pipe with the limited external space is achieved, and single-face welding and double-face forming of all-position butt welding seams with the welding groove alignment tolerance smaller than or equal to 2 mm and the gap smaller than or equal to 0.5 mm are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of nuclear power product welding, and in particular to a single-sided welding and double-sided forming welding process. Background Art

[0002] The integrated small reactor reactor pressure vessel adopts an integrated design. The heat exchange assembly is built into the reactor pressure vessel cylinder and fixed by welding. The upper and lower pipe box assemblies of the heat exchange assembly are welded by 8 pipe boxes and 4 pipe box connectors, respectively. The materials are 690 nickel-based alloy and 316LN stainless steel. The 24 pipes of the pipe box assembly are then connected to the corresponding interfaces on the pressure vessel cylinder. The outer diameter of the pipe box interface is 686mm, the inner diameter is 550mm, and the wall thickness is about 68mm. The outer diameter of the pipe box connector interface is 290mm, the inner diameter is 200mm, and the wall thickness is about 45mm. The butt weld is a full penetration pressure weld with high welding quality requirements. Defects such as welding cracks, lack of fusion, slag inclusions and pores are not allowed. However, due to the poor weldability of nickel-based alloys and stainless steel, TIG welding is generally used to fill the weld to ensure the quality of the weld. Due to the limited external space of the product structure, it is difficult to use the commonly used manual argon arc welding method of primer and root cleaning for root welding. Only single-sided welding and double-sided forming can be performed from the inside of the pipe. Since the thickness of the butt weld reaches 45 / 68mm, the manual TIG welding filling method is labor-intensive and difficult to ensure the stability of the weld quality. Therefore, mechanical argon arc welding is used to primer, fill and cover the weld to ensure the weld quality.

[0003] Since the total weight of the pressure vessel assembly is about 250 tons, the height is about 11303mm, and the inner diameter of the cylinder is about 3700mm; the total weight of the heat exchange assembly is about 78 tons, the height is about 9000mm, and the maximum diameter is 3600mm. Overall, it has the characteristics of large size and heavy tonnage. Therefore, a vertical work station is used for the assembly and welding of the pressure vessel cylinder and the heat exchange assembly. The butt welds of the 24 pipes need to be welded in full position. At this time, the positions and sizes of the 24 pipe ports have been processed in place. In the prior art, the welding of a single pipe alone cannot effectively control the welding deformation during the welding process, which results in the inability to guarantee the groove gap and the misalignment during the subsequent welding of the pipe, and the assembly size cannot be controlled.

[0004] When using the single-sided welding and double-sided forming technology, whether the root of the weld is fully penetrated will directly affect the quality of the weld. If there are defects at the root, it is impossible to repair on the back of the weld, so the single-sided welding and double-sided forming weld must be qualified once during welding. Therefore, it is also particularly important to design a reasonable groove type, control the precision of the groove size during machining, align the center during assembly, and control the welding deformation during welding. The existing full-position automatic TIG welding process can theoretically achieve the requirements of single-sided welding and double-sided forming of grooves with a misalignment and gap of 0.5mm, but in actual use, under the machining accuracy of the existing technology, since 24 pipes need to be installed with the cylinder at the same time, there will definitely be large gaps and misalignments in the weld groove after assembly, which has an adverse effect on the quality assurance of the root base weld, and the existing technology is difficult to guarantee the welding quality. Summary of the invention

[0005] The purpose of the present invention is to provide a single-sided welding and double-sided forming welding process to achieve automatic TIG welding (non-melting inert gas shielded arc welding) of the inner wall of a horizontally fixed pipe with limited external space.

[0006] In order to achieve the above-mentioned object, the present invention provides a single-sided welding and double-sided forming welding process, which uses a welding device to weld the interface of the cylinder and the pipe of the heat exchange component together; the specific steps of the welding process include:

[0007] Step 1: confirm the welding target parameters, use the lifting equipment to insert the heat exchange component into the cylinder, make the cylinder and the heat exchange component in a vertical position, and make the interface on one side of the cylinder correspond to the pipe at one end of the heat exchange component;

[0008] Step 2, using the welding device to spot weld and position the welding groove formed by each cylinder interface and the pipe of the heat exchange component;

[0009] Step 3, a welding device is respectively fixed on the outer wall of the nozzles in 2n mutually symmetrical directions on one side of the cylinder, so that the interface of the inner wall of the pipe connected to the cylinder with the welding device fixed thereon is welded at the same time; wherein the nozzle is an extension of the interface of the inner wall of the cylinder on the outer wall of the cylinder; and 2≤2n≤the number of interfaces on one side of the cylinder;

[0010] Step 4, after completing this welding, remove the 2n welding devices from the nozzles of the cylinder, and reinstall them on other unwelded nozzles that are symmetrical to each other on one side of the cylinder, and complete welding again; repeat step 3 until all the interfaces on one side of the cylinder and the pipe ports of the heat exchange assembly are connected together;

[0011] Step 5, turn over the cylinder and the heat exchange component inside it, and repeat steps 2-4 to complete the welding of the other side of the cylinder and the heat exchange component.

[0012] Optionally, the welding device comprises:

[0013] A guide rail is arranged outside the nozzle; and the guide rail is an annular structure, and its diameter matches the diameter of the nozzle on the cylinder;

[0014] A plurality of fixing components are evenly arranged on the outside of the guide rail so that the guide rail is fixed above the nozzle port;

[0015] The welding equipment component has one end arranged on the guide rail and the other end extending into the interior of the barrel nozzle and can move along the guide rail to weld the interface of the barrel and the pipe of the heat exchange component together.

[0016] Optionally, the welding equipment assembly comprises:

[0017] A driving motor is arranged on the guide rail and can move along the guide rail;

[0018] The welding head is arranged below the driving motor and can move together with the driving motor;

[0019] The connecting rod is a telescopic rod, one end of which is arranged on the welding machine head and can move along the guide rail together with the driving motor; the other end of the connecting rod extends into the nozzle;

[0020] A camera, arranged on the connecting rod, can take pictures of the welding position;

[0021] The welding gun is arranged at one end of the connecting rod in the nozzle; and a polishing tool is arranged on one side of the welding gun, and the polishing tool can be used to polish the welding position after the welding is completed.

[0022] Optionally, the welding gun is provided with:

[0023] Tungsten electrode, generates arc, and welds the welding groove;

[0024] Several gas supply ports are arranged beside the tungsten electrode, and the protective gas flow rate in each gas supply port is different, providing main gas flow protection and auxiliary gas flow protection for the welding process;

[0025] The wire feeding nozzle is set next to the tungsten electrode and actively fills the wire during the welding process.

[0026] Optionally, each set of the fixing components includes:

[0027] A connecting plate, fixed on the outer side of the guide rail;

[0028] The support frame is L-shaped, one end of which is fixed to the connecting plate, and the other end surface of which is provided with a fixing hole;

[0029] The fixing piece can pass through the fixing hole, and the bottom end of the fixing piece can contact the outer wall of the nozzle, so that the guide rail can be clamped on the nozzle of the barrel.

[0030] Optionally, the welding groove gap is less than or equal to 2 mm, and the misalignment is less than or equal to 0.5 mm.

[0031] Optionally, in step 3, the connecting rod of each welding device and the welding gun fixed on one end of the connecting rod are extended into the corresponding welding groove, and the bottom ends of the two symmetrically positioned fixings on the welding device are inserted into the fixing holes of the support frame, and rotated along the first thread on the inner wall of the fixing hole of the support frame so that the bottom end of the fixing is in contact with the outer wall of the nozzle; the installation of the two centrally symmetrical fixings on the welding device is completed in sequence, so that the guide rail is clamped on the outer wall of the nozzle through the fixings and the support frame; and the position of the support frame is continuously adjusted so that the center of the guide rail is coaxially placed with the nozzle port.

[0032] Optionally, in step 3, before starting the welding head for welding, start the drive motor to make the welding head move half a circle along the guide rail, and check whether the distance between the tungsten electrode and the wire feeding nozzle on the welding gun that extends into the welding groove position and the welding groove meets the requirements of the welding target parameters, and then determine whether the guide rail and the nozzle port are coaxially installed.

[0033] Optionally, in step 3, the welding at the welding groove needs to complete at least three layers of welding, which are:

[0034] For base welding, the welding gun swings during welding; the number of passes per layer is designed according to the width of the welding groove, and the maximum welding current and maximum wire feeding speed of the welding equipment components are used, and the welding gun is swung while the wire is filled;

[0035] Filling welding, the welding gun does not swing and fills the wire to fill the metal in the welding groove;

[0036] Cover welding is the last layer in the welding process. The camera can be used to observe whether the metal in the welding groove fills the weld and determine whether filler wire is needed.

[0037] Optionally, the arc starting point and arc ending point on each layer of weld are staggered, and the distance between the arc starting point and the arc ending point is 50-100 mm.

[0038] Compared with the prior art, the technical solution of the present invention has at least the following beneficial effects:

[0039] The welding process described in the present invention is to fix by one-time spot welding, and then weld multiple mutually symmetrical positions in the cylinder interface at the same time to ensure balanced force during the connection between the cylinder and the heat exchange component, so that the gap at the welding groove is less than or equal to 2mm, and the misalignment is less than or equal to 0.5mm.

[0040] The welding process of the present invention adopts mechanical argon arc welding to realize TIG automatic welding in all positions. The maximum current in the welding parameters is used during base welding to ensure that the bottom end of the welding groove is welded through and the positioning spot welding is completely melted through. The welding equipment component adopts the maximum wire feeding speed and increases the amount of filling wire to prevent cracks from appearing at the bottom end of the welding groove.

[0041] The welding device of the present invention can realize automatic TIG welding of the inner wall of a horizontally fixed pipe with limited external space by setting a guide rail, a welding head and a connecting rod running along the guide rail; and can be applied to the pipe to be welded with a minimum inner diameter of 200mm and a wall thickness of 45mm, and complete the single-sided welding and double-sided forming of the welding groove with a misalignment of less than or equal to 2mm and a misalignment of less than or equal to 0.5mm. And the welding joint is provided with a polishing tool, which can polish each layer of the weld after the base welding is completed to remove the poorly formed parts, oxides and impurities at the welding position.

[0042] The welding head of the welding device of the present invention is equipped with a polishing tool to meet the requirements of polishing and cleaning each layer of the weld. At the same time, the welding equipment is equipped with a high-definition camera to observe the molten pool and weld formation during the welding process. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a schematic diagram of the cylinder structure.

[0044] Figure 2 Schematic diagram of the heat exchange component structure.

[0045] Figure 3 Schematic diagram of welding groove.

[0046] Figure 4 It is a schematic structural diagram of the welding device for single-sided welding and double-sided forming according to the present invention.

[0047] In the figure, 1-cylinder, 11-interface, 12-nozzle, 2-heat exchange component, 21-connecting pipe, 3-welding groove, 4-guide rail, 51-connecting plate, 52-support frame, 53-fixing part, 61-driving motor, 62-connecting rod, 63-welding gun. DETAILED DESCRIPTION

[0048] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] In the description of the present invention, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0050] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0051] The reactor pressure vessel includes: a cylinder 1 and a heat exchange component 2. Figure 1 As shown, the cylinder 1 is a hollow cylinder with a plurality of interfaces 11 at both ends, and a plurality of corresponding nozzles 12 are provided where the interfaces 11 on the inner wall of the cylinder 1 extend to the outer wall of the cylinder. Figure 2 As shown, the heat exchange component 2 is provided with a plurality of pipes 21 at both ends, and the positions of the pipes 21 correspond to the positions of the plurality of interfaces 11 on the cylinder 1, so that after the heat exchange component 2 is inserted into the cylinder 1, the interfaces 11 of the cylinder 1 contact with the pipes 21 of the heat exchange component 2 to form a welding groove 3, as shown in FIG. Figure 3 shown.

[0052] like Figure 4 As shown, the present invention provides a full-position TIG welding single-sided welding and double-sided forming welding device, which is fixed on the nozzle 12 of the cylinder 1 and is used to weld the interface 11 of the inner wall of the nozzle 12 on the cylinder 1 and the connecting pipe 21 of the heat exchange component 2 together. The welding device includes: a guide rail 4, a plurality of fixed components, and a welding equipment component. The guide rail 4 is located on the outside of the nozzle 12, and a plurality of the fixed components are evenly arranged on the outside of the guide rail 4 to fix the guide rail 4 above the port of the nozzle 12; one end of the welding equipment component is arranged on the guide rail 4, and the other end extends into the inside of the nozzle 12, and can move along the guide rail 4 to weld the cylinder 1 and the heat exchange component 2 together.

[0053] The guide rail 4 is an annular structure, and its diameter matches the diameter of the nozzle 12 on the cylinder 1 .

[0054] Each set of the fixing components includes: a connecting plate 51, a support frame 52, and a fixing member 53. The connecting plate 51 is fixed to the outside of the guide rail 4; the support frame 52 is L-shaped, one end of which is fixed to the connecting plate 51, and a fixing hole is provided on the surface of the other end. The fixing member 53 can pass through the fixing hole, and its bottom end contacts the outer wall of the nozzle 12, so that the guide rail 4 is clamped on the nozzle 12 of the barrel 1.

[0055] In a preferred embodiment, the connecting plates 51 in the plurality of fixing components are symmetrically arranged on the outer side of the guide rail 4 with the center of the circle of the guide rail 4 as the center.

[0056] Furthermore, the inner wall of the fixing hole of the support frame 52 is provided with a first thread, and the fixing member 53 is a bolt, and the surface of the bolt is provided with a second thread matching the first thread of the inner wall of the fixing hole, so that the support frame 52 and the fixing member 53 can be connected together by threads.

[0057] When installing the guide rail 4, the center of the guide rail 4 is coaxially arranged with the port of the nozzle 12. At this time, the fixing members 53 in the symmetrical position fixing assembly are installed in sequence, so that the bottom end of the fixing member 53 passes through the fixing hole of the support frame 52 and rotates along the first thread of the inner wall of the fixing hole until the bottom end of the fixing member 53 contacts the outer wall of the nozzle 12, thereby fixing the guide rail 4 on the outer side of the nozzle 12.

[0058] The welding equipment assembly is connected to the operating table signal, and the working state of the welding equipment assembly can be adjusted through the operating table. The welding equipment assembly includes: a welding gun 63, a drive motor 61, a welding head, a connecting rod 62, and a camera. The drive motor 61 is arranged on the guide rail 4, driving the welding head to move along the guide rail 4. The welding head is arranged below the drive motor, and the drive motor 61 can drive the welding head to move; the connecting rod 62 is a telescopic rod, one end of which is arranged on the welding head driven by the drive motor 61, and can move along the guide rail 4 with the drive motor 61; the other end of the connecting rod 62 extends into the pipe to reach the position of the welding groove where the interface 11 is connected to the heat exchange component pipe. The camera is arranged on the connecting rod 62, which can shoot the welding position and transmit it to the operating table in real time, so that the operator can see the welding condition of the welding groove 3.

[0059] Specifically, the surface of the guide rail 4 is provided with teeth, and the bottom end of the drive motor 61 is provided with a drive gear meshing with the guide rail 4. The drive motor 61 drives the drive gear to rotate, thereby causing the drive motor 61 to move along the teeth on the surface of the guide rail 4, and finally drives the connecting rod to rotate along the guide rail 4.

[0060] The welding gun 63 is provided with a tungsten electrode, a plurality of air supply ports, a wire feeding nozzle, and a polishing tool. The tungsten electrode can generate an arc to weld the welding groove 3. The plurality of air supply ports are arranged next to the tungsten electrode, and the protective gas flow rate in each air supply port is different, so as to provide main airflow protection and auxiliary airflow protection for the welding process. The wire feeding nozzle is arranged next to the tungsten electrode, so as to actively fill the wire during the welding process. The polishing tool is arranged on one side of the welding gun 63, and the welding position can be polished by the polishing tool after the tungsten electrode completes the welding. The welding gun 63 is arranged on one end of the connecting rod 62 located at the welding groove, and the length of the connecting rod 62 can be adjusted so that the tungsten electrode is located at the welding groove 3 formed by the cylinder 1 and the heat exchange component 2. At this time, when the driving motor 61 performs a circular motion along the guide rail 4, the driving motor 61 can sequentially drive the connecting rod 62 and the welding gun 63 to perform a circular motion, so that the welding gun 63 welds the welding groove 3, and completes the connection between the interface 11 of the cylinder 1 and the connecting pipe 21 of the heat exchange component 2.

[0061] The specific steps of using the welding device of the present invention to complete the welding process include:

[0062] Step 1: confirm the welding target parameters and adjust the positions of the cylinder 1 and the heat exchange component 2.

[0063] According to the requirements, the tolerance target of the machining dimension is controlled to be less than or equal to 0.1mm. Using the lifting equipment, the heat exchange component 2 is inserted into the cylinder 1, so that the cylinder 1 and the heat exchange component 2 are in a vertical position; at the same time, the interface 11 on one side of the cylinder 1 is respectively set corresponding to the pipe 21 at one end of the heat exchange component 2, so that the gap of the formed welding groove 3 is less than or equal to 2mm, and the misalignment is less than or equal to 0.5mm.

[0064] Step 2: Spot welding positioning.

[0065] The welding device is used to spot weld and position the welding groove 3 formed by the interface 11 of each cylinder 1 and the pipe 21 of the heat exchange component 2, and after each welding groove 3 is positioned, the gap and misalignment of the welding groove 3 must be measured to see if they meet the requirements to ensure assembly accuracy.

[0066] Step 3: Use the welding device to weld the cylinder and the heat exchange component.

[0067] An annular guide rail 4 matching the diameter of the interface 11 of the cylinder 1 is selected, and a welding device is respectively fixed on the outer wall of the nozzles 12 in 2n (2≤2n≤number of interfaces on one side of the cylinder) mutually symmetrical positions at the top of the cylinder 1, so that the interfaces 11 in multiple positions of the cylinder 1 can be welded simultaneously, ensuring that the cylinder 1 and the heat exchange assembly 2 will not be misaligned. Among them, the positions of the nozzles 12 in the selected multiple positions are mutually axially symmetrical.

[0068] In a preferred embodiment, one welding device is provided on each nozzle 12 on one side of the cylinder 1 , so as to save welding processing time and prevent misalignment between the cylinder 1 and the heat exchange component 2 .

[0069] In a preferred embodiment, when there are multiple (especially multiples of 4) nozzles 12 on the barrel 1, in order to save the number of welding devices used and reduce process costs, during the welding process, a batch of 4 welding devices are used and respectively fixed on four mutually symmetrical nozzles 12 at the top of the barrel 1 to complete the welding; and after the welding is completed, the installation position of the welding device is replaced until the welding of all interfaces 11 at the top of the barrel 1 is completed.

[0070] Insert the connecting rod 62 of each welding device and the welding gun 63 fixed on one end of the connecting rod 62 into the corresponding nozzle 12, so that the welding gun 63 corresponds to the position of the welding groove, and insert the bottom ends of the two fixing members 53 in symmetrical positions on the welding device into the fixing holes of the support frame 52, and rotate along the first thread on the inner wall of the fixing hole of the support frame 52, so that the bottom ends of the fixing members 53 contact the outer wall of the nozzle 12; complete the installation of the two fixing members 53 in the central symmetrical positions on the welding device in sequence, and then make the guide rail 4 and the support frame 52 clamped on the outer wall of the nozzle 12 through the fixing members 53; and continuously adjust the position of the support frame 52 so that the center of the guide rail 4 is coaxially placed with the port of the nozzle 12; the position of the welding joint 63 can be observed by a camera, and the connecting rod 62 of the welding device can be adjusted to be retracted so that the welding gun 63 is aligned with the welding groove 3.

[0071] Before starting the welding gun 63 for welding, start the driving motor 61 to make the welding gun 63 move half a circle along the guide rail 4, check whether the distance between the tungsten electrode, wire feed nozzle and welding groove 3 on the welding gun 63 meets the requirements of the welding target parameters, and then determine whether the guide rail 4 and the nozzle 12 port are coaxially installed to ensure that the weld welded by the welding gun 63 after rotating along the guide rail 4 meets the welding target parameters. When the distance between the tungsten electrode, wire feed nozzle and welding groove 3 on the welding gun 63 meets the project requirements, start the 2n welding devices installed on the cylinder 1 at the same time, so that the welding gun 63 in each welding device rotates along the guide rail 4 while welding, and form a weld at the welding groove 3.

[0072] Specifically, during the welding process, the shielding gas is turned on and the arc is generated by the tungsten electrode, so that the welding position is not affected by the oxides in the air. Each welding groove 3 needs to complete at least three layers of welding, and the parameters of the welding gun 63 for completing three layers of welding are shown in Table 1.

[0073] Table 1 Welding head parameter range

[0074]

[0075] The first layer of welding is the base welding. The bottom side wall of the welding groove 3 is ensured to be more easily melted through by swinging the welding gun 63 during welding (the welding joint moves forward and backward or left and right at a fixed frequency); since the width of the welding groove may shrink and deform during the welding process, the number of welding rows (i.e., welds) should be designed according to the width of the welding groove before welding each layer of welds, and the maximum welding current and maximum wire feeding speed of the welding equipment component parameters should be used, and the welding gun 63 should be swung while filling the wire. At this time, the polishing tool on the welding gun 63 is used to polish each layer of each weld to ensure a smooth transition between the overlapping areas of the welds, so that there is no visible weld ripple on the surface of each layer of welds, and the weld joints and the arc pit area have a smooth transition to ensure the penetration of the weld joints, and remove the poorly formed areas, oxides and impurities.

[0076] The second layer of welding is a filling welding, in which the welding gun 63 is not swung and the wire is filled to fill the welding groove 3 with metal.

[0077] The third layer is the cover welding, which is the last layer in the welding process. The camera can be used to observe whether the metal in the welding groove 3 fills the weld and determine whether filler wire is needed.

[0078] Furthermore, during the welding process, the welding situation can be observed in real time through the camera to determine whether the weld polishing meets the requirements and the situation of the weld formation.

[0079] In a preferred embodiment, filling welding can be repeated multiple times during the welding process to allow metal to fill the welding groove 3.

[0080] Specifically, during the welding process, the distance and angle between the tungsten electrode and the side wall of the groove are controlled according to the project requirements. At the same time, the center of the tungsten electrode (arc center) is controlled to align with the edge of the weld to avoid defects such as unfused side walls and undercuts. The arc starting and arc ending points on each layer of the weld are staggered, and the distance between the arc starting and arc ending points is 50-100mm.

[0081] Specifically, the tungsten electrode is a lanthanum tungsten electrode (La2O3≥1.8%) with a diameter of 4.0mm, which is used to ensure the stability of the arc during welding and prevent the tungsten electrode from burning due to excessive filling. At the same time, the tungsten electrode of the welding gun 63 is replaced at least once every 3 welding turns to prevent the tungsten electrode from burning and affecting the welding quality. The shielding gas is argon with a purity of 99.999%, and the argon flow rate in the gas supply port for main airflow protection is 15-50L / min, and the argon flow rate in the gas supply port for auxiliary airflow protection is 30-100L / min. The metal used for filling wire is ERNiCrFe-7A, and a welding wire with a diameter of 0.9mm is selected to be filled into the welding groove 3 from the wire feeding nozzle. In the welding process, the welding position is not preheated or post-heated, and the welding temperature is controlled to be less than or equal to 177°C.

[0082] Step 4, after completing this welding, remove the 2n welding devices from the nozzle 12 of the cylinder 1, and reinstall them on the other 2n nozzles 12 that are symmetrical to each other at the top of the cylinder 1, and complete the welding again; repeat step 3 until the interface 11 on one side of the cylinder 1 and the port 21 of the heat exchange component 2 are all connected together.

[0083] Step 5, turn over the cylinder 1 and the heat exchange component 2 therein, and repeat steps 2-4 to complete welding of the cylinder 1 and the other side of the heat exchange component 2.

[0084] In summary, the protection device of the present invention is capable of realizing automatic TIG welding of the inner wall of a horizontally fixed pipe with limited external space by setting a guide rail, and a welding head and a connecting rod running along the guide rail; the protection process of the present invention is a method of simultaneously welding multiple mutually symmetrical cylinder interfaces after one-time spot welding, so as to realize single-sided welding and double-sided forming of 24 pipe welding groove misalignments less than or equal to 2mm and gaps less than or equal to 0.5mm in all positions.

[0085] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

Claims

1. A single-sided welding and double-sided forming welding process, characterized in that: The interface of the cylinder and the pipe of the heat exchange component are welded together using a welding device; the specific steps of the welding process include: Step 1: confirm the welding target parameters, use the lifting equipment to insert the heat exchange component into the cylinder, make the cylinder and the heat exchange component in a vertical position, and make the interface on one side of the cylinder correspond to the pipe at one end of the heat exchange component; Step 2, using the welding device to spot weld and position the welding groove formed by each cylinder interface and the pipe of the heat exchange component; Step 3, a welding device is respectively fixed on the outer wall of the nozzles in 2n mutually symmetrical directions on one side of the cylinder, so that the interface of the inner wall of the pipe connected to the cylinder with the welding device fixed thereon is welded at the same time; wherein the nozzle is an extension of the interface of the inner wall of the cylinder on the outer wall of the cylinder; and 2≤2n≤the number of interfaces on one side of the cylinder; Step 4, after completing this welding, remove the 2n welding devices from the nozzles of the cylinder, and reinstall them on other unwelded nozzles that are symmetrical to each other on one side of the cylinder, and complete welding again; repeat step 3 until all the interfaces on one side of the cylinder and the pipe ports of the heat exchange assembly are connected together; Step 5, turn over the cylinder and the heat exchange component inside it, and repeat steps 2-4 to complete the welding of the other side of the cylinder and the heat exchange component.

2. The single-sided welding and double-sided forming welding process according to claim 1 is characterized in that: The welding device comprises: A guide rail is arranged outside the nozzle; and the guide rail is an annular structure, and its diameter matches the diameter of the nozzle on the cylinder; A plurality of fixing components are evenly arranged on the outside of the guide rail so that the guide rail is fixed above the nozzle port; The welding equipment component has one end arranged on the guide rail and the other end extending into the interior of the barrel nozzle and can move along the guide rail to weld the interface of the barrel and the pipe of the heat exchange component together.

3. The single-sided welding and double-sided forming welding process according to claim 2 is characterized in that: The welding equipment assembly comprises: A driving motor is arranged on the guide rail and can move along the guide rail; A welding head, wherein the welding joint is arranged below the driving motor and can move with the driving motor; The connecting rod is a telescopic rod, one end of which is arranged on the welding machine head and can move along the guide rail together with the driving motor; the other end of the connecting rod extends into the nozzle; A camera, arranged on the connecting rod, can take pictures of the welding position; The welding gun is arranged on one end of the connecting rod in the nozzle; and a polishing tool is arranged on one side of the welding gun, and the polishing tool can be used to polish the welding position after the welding is completed.

4. The single-sided welding and double-sided forming welding process according to claim 3 is characterized in that: The welding gun is provided with: Tungsten electrode, generates arc, and welds the welding groove; Several gas supply ports are arranged beside the tungsten electrode, and the protective gas flow rate in each gas supply port is different, providing main gas flow protection and auxiliary gas flow protection for the welding process; The wire feeding nozzle is set next to the tungsten electrode and actively fills the wire during the welding process.

5. The single-sided welding and double-sided forming welding process according to claim 2 is characterized in that: Each set of the fixing components comprises: A connecting plate, fixed on the outer side of the guide rail; The support frame is L-shaped, one end of which is fixed to the connecting plate, and the other end surface of which is provided with a fixing hole; The fixing piece can pass through the fixing hole, and its bottom end can contact the outer wall of the nozzle, so that the guide rail is clamped on the nozzle of the barrel.

6. The single-sided welding and double-sided forming welding process according to claim 1 is characterized in that: The welding groove gap is less than or equal to 2 mm, and the misalignment is less than or equal to 0.5 mm.

7. The single-sided welding and double-sided forming welding process according to claim 6 is characterized in that: In the step 3, the connecting rod of each welding device and the welding gun fixed on one end of the connecting rod are extended into the corresponding welding groove, and the bottom ends of the two fixing members in symmetrical positions on the welding device are inserted into the fixing holes of the support frame, and rotated along the first thread on the inner wall of the fixing hole of the support frame, so that the bottom end of the fixing member contacts the outer wall of the nozzle; the installation of the two fixing members in the central symmetrical position on the welding device is completed in sequence, and then the guide rail is clamped on the outer wall of the nozzle through the fixing member and the support frame; The position of the support frame is continuously adjusted so that the center of the guide rail is coaxially placed with the nozzle port.

8. The single-sided welding and double-sided forming welding process according to claim 4 is characterized in that: In step 3, before starting the welding head for welding, start the drive motor to make the welding head move half a circle along the guide rail, check whether the distance between the tungsten electrode and the wire feeding nozzle on the welding gun that extends into the welding groove position and the welding groove meets the requirements of the welding target parameters, and then determine whether the guide rail and the nozzle port are coaxially installed.

9. The single-sided welding and double-sided forming welding process according to claim 4 is characterized in that: In step 3, the welding at the welding groove needs to complete at least three layers of welding, which are: For base welding, the welding gun swings during welding; the number of passes per layer is designed according to the width of the welding groove, and the maximum welding current and maximum wire feeding speed of the welding equipment components are used, and the welding gun is swung while the wire is filled; Filling welding, the welding gun does not swing and fills the wire to fill the metal in the welding groove; Cover welding is the last layer in the welding process. The camera can be used to observe whether the metal in the welding groove fills the weld and determine whether filler wire is needed.

10. The single-sided welding and double-sided forming welding process according to claim 9, characterized in that: The arc starting point and arc ending point on each layer of weld are staggered, and the distance between the arc starting point and the arc ending point is 50-100 mm.

Images