A duplex stainless steel sheet welding apparatus and process

Abstract

The application provides a duplex stainless steel sheet welding device and process. The duplex stainless steel sheet welding device comprises a chassis, a mounting plate is fixedly connected to the chassis, a first electric push rod is fixedly connected to the mounting plate, and a multi-stage telescopic mechanism is arranged at the telescopic end of the first electric push rod. The mechanism is composed of a plurality of iron cylindrical pipes. Through the above-mentioned cylindrical pipe design adopting a multi-stage iron concentric nested structure and integrating an electromagnetic locking and cooling cavity, the device is significantly improved in function and performance. The design drives each stage of the cylindrical pipe to perform axial telescopic movement through the first electric push rod, and cooperates with the on-off circuit control of the electromagnet to realize the rapid and accurate adaptation of a single mold core to multiple diameter specifications, thereby effectively solving the problems of operation interruption, high labor intensity and low production efficiency caused by the replacement of the whole mold core for each different diameter cylinder machining in the prior art.

Description

Technical Field

[0001] This application relates to the field of welding technology, specifically to a welding apparatus and process for duplex stainless steel sheets. Background Technology

[0002] With the continuous development of industrial production, stainless steel sheets have been widely used in various fields due to their excellent corrosion resistance, aesthetics and mechanical properties, such as automobile manufacturing, home appliances, aerospace, and kitchenware manufacturing. These fields have put forward high precision, high efficiency and high quality requirements for welding technology, which has promoted the continuous progress of stainless steel sheet welding technology.

[0003] However, the existing stainless steel sheet rolling and welding process has significant technical defects: First, in the rolling and forming process, the integral mold core and matching forming equipment need to be changed frequently for processing cylinders of different diameters, which leads to interruption of production continuity, excessive equipment adjustment time, and increased labor intensity, which seriously restricts production efficiency and equipment utilization.

[0004] Secondly, in terms of welding process, the welding of duplex stainless steel 2205 thin plates (thickness range 0.8-2.0mm) faces severe metallurgical challenges. The proportion of austenite phase in the weld area is significantly reduced compared to the base metal (the ideal two-phase structure is about 50% austenite and 50% ferrite). This phase imbalance directly leads to serious deterioration of the corrosion resistance and mechanical properties of the welded joint. In addition, traditional welding methods lack effective molten pool protection and precise heat input control mechanisms, making it difficult to achieve high-quality single-sided welding with double-sided forming process, and failing to guarantee the stability of weld microstructure and properties. Summary of the Invention

[0005] In order to solve the problems existing in the prior art, the purpose of this application is to provide a welding apparatus and process for duplex stainless steel sheets.

[0006] The duplex stainless steel sheet welding device described in this application includes a base frame, on which a mounting plate is fixedly connected;

[0007] A first electric push rod is fixedly attached to the mounting plate. The telescopic end of the first electric push rod is equipped with a multi-stage telescopic mechanism, which is composed of multiple iron cylindrical tubes. The multiple cylindrical tubes adopt a concentric nested telescopic design, and their diameters decrease from the outermost layer to the innermost layer. A fixing rod is fixedly attached to the mounting plate, and a cross is fixedly attached to the fixing rod. The cross is fixedly connected to the innermost cylindrical tube, and an electromagnet is fixedly attached to the inner ring surface of the cylindrical tube.

[0008] The mounting plate has a pressing mechanism connected to its inner wall. This mechanism can press the stainless steel sheet, which, with the help of a cylindrical tube, will be pressed into a cylindrical shape. The mounting plate also has a welding mechanism that can weld the joints of the cylindrical stainless steel sheet.

[0009] Furthermore, it is particularly preferred that the cylindrical tube has a cavity inside for containing coolant, and the cavity on the cylindrical tube is connected to an inlet pipe and an outlet pipe.

[0010] Furthermore, it is particularly preferred that the pressing mechanism includes an electric slide rail fixedly connected to the inner wall of the mounting plate, a first electric slider slidably connected to the electric slide rail, a support plate fixedly connected to the first electric slider, a hydraulic cylinder fixedly connected to the support plate, and a pressing plate fixedly connected to the telescopic part of the hydraulic cylinder.

[0011] Furthermore, it is particularly preferred that one side of the pressing plate is set as a curved surface.

[0012] Furthermore, it is particularly preferred that the device also includes a moving mechanism, which is connected to the base frame, and a second electric push rod is fixedly connected to the moving mechanism. The telescopic part of the second electric push rod is fixedly connected to a fixing plate.

[0013] Furthermore, it is particularly preferred that a groove is provided on the cylindrical tube, and an air extraction pipe and an air intake pipe pass through the cylindrical tube. The end of the air extraction pipe is located at the rightmost end of the groove. An air bladder is fixedly connected to the groove, and a fixing pipe is connected to the air bladder. The fixing pipe is connected to the air intake pipe.

[0014] Furthermore, it is particularly preferred that the welding mechanism includes a bracket fixed to the mounting plate, a third electric slide rail fixed to the bracket, a third electric slider slidably connected to the third electric slide rail, a third electric push rod fixed to the third electric slider, and a welding torch fixed to the telescopic part of the third electric push rod.

[0015] Furthermore, it is particularly preferred that the welding mechanism also includes a fourth electric push rod fixedly connected to the bracket, an L-shaped plate fixedly connected to the telescopic part of the fourth electric push rod, a protective shell fixedly connected to the L-shaped plate, the protective shell being made of rubber, an air outlet pipe fixedly connected to the right end of the protective shell, a first conveying pipe and a second conveying pipe fixedly connected to the left end of the protective shell, and a rubber strip provided on the top of the protective shell, the rubber strip being made of high temperature resistant material.

[0016] Furthermore, it is particularly preferred that the moving mechanism includes a second electric slide rail fixedly connected to the base frame, a second electric slider slidably connected on the second electric slide rail, the second electric slider being fixedly connected to a second electric push rod, and an electric suction cup fixedly connected inside the fixed plate.

[0017] Furthermore, a particularly preferred method is a welding process for duplex stainless steel sheets, the specific steps of which are as follows:

[0018] S1. Preparation and positioning: Place the duplex stainless steel sheet onto the pressing plate using an external transfer device. Control the first electric slider to move upward along the first electric slide rail so that the sheet contacts the outer wall of the outermost cylindrical tube. Then control the second electric push rod to drive the fixing plate to move upward, and use the fixing plate to attract and press the sheet against the surface of the cylindrical tube.

[0019] S2. Rolling and forming: Start the hydraulic cylinder to drive the pressing plate with the arc surface to move along the outer ring surface of the cylindrical tube to gradually press the stainless steel sheet into a cylindrical shape and ensure that the two ends of its joint are tightly fitted.

[0020] S3. Diameter adjustment: If it is necessary to process small and medium diameter cylinders, control the electromagnets of the corresponding level to de-energize and drive the first electric push rod to retract, so that the outermost cylindrical tube moves axially and exposes the working surface of the mold core of the target diameter. Repeat step S2 to complete the rolling.

[0021] S4. Back gas protection: After rolling, the seam is aligned with the groove; pure nitrogen is introduced into the groove through the air inlet pipe, and the airbag is expanded to seal the gap between the groove and the cylindrical stainless steel sheet. At the same time, the air in the groove is replaced with pure nitrogen through the air extraction pipe to form a back protective environment.

[0022] S5. Welding protection preparation: Control the fourth electric push rod to drive the protective shell to move down, so that a sealed space is formed between the protective shell, the rubber strip and the stainless steel sheet; then exhaust the air in the space through the air outlet pipe, and introduce a mixed protective gas composed of 90%-95% argon and 5%-10% nitrogen through the second delivery pipe.

[0023] S6. Welding execution: Start the welding torch and control the third electric slider to move at a constant speed along the third electric slide rail to weld the butt joint.

[0024] S7. Post-weld front protection: After welding is completed, the mixed gas inside the protective shell is discharged, and pure nitrogen is introduced into the shell through the first delivery pipe to provide front protection for the high-temperature weld.

[0025] S8. Demolding: When it is necessary to remove the cylindrical stainless steel sheet from the cylindrical tube 4, control the second electric push rod to move the fixing plate down so that the fixing plate is no longer pressing against the stainless steel sheet. Then control the second electric slider to slide to the right on the second electric slide rail, so that the cylindrical stainless steel sheet will separate from the cylindrical tube. Then, it can be removed from the electric suction cup by the worker or electric clamp.

[0026] The advantages of the duplex stainless steel sheet welding apparatus and process described in this application are as follows:

[0027] A. The present invention uses a fixing plate to contact the stainless steel sheet and firmly press the stainless steel sheet against the cylindrical tube, thereby avoiding the stainless steel sheet from moving on the cylindrical tube after being pressed into a cylindrical shape by the pressing plate, which would otherwise cause a deviation between the joint and the weld of the rolled stainless steel sheet.

[0028] B. The present invention also transfers the heat generated by the stainless steel sheet to the cylindrical tube, and the heat of the cylindrical tube is carried away by the coolant. In this way, the cylindrical tube can continuously transfer heat to the stainless steel sheet, so that the stainless steel sheet is effectively cooled, thereby achieving an active heat dissipation effect on the welding area and effectively suppressing the thermal deformation of the sheet.

[0029] C. The present invention also achieves a significant improvement in function and performance through the above-mentioned cylindrical tube design that adopts a multi-level iron concentric nested structure and integrates electromagnetic locking and cooling cavity. The design drives the cylindrical tubes of each level to perform axial telescopic movement through the first electric push rod, and with the help of the on and off circuit control of the electromagnet, it realizes the rapid and accurate adaptation of a single mold core to multiple diameter specifications. This effectively solves the problems of work interruption, high labor intensity and low production efficiency caused by the need to replace the entire mold core every time a different diameter cylinder is processed in the prior art.

[0030] Meanwhile, through the synergistic effect of the hydraulic cylinder and the arc-shaped pressing plate, the pressing plate can adapt to the contours of cylindrical tubes with different outer diameters and move stably along its outer ring surface, gradually pressing the stainless steel sheet into a cylindrical shape. This structure enhances the adaptability to forming workpieces with different diameters and solves the problem that the corresponding extrusion equipment must be adjusted or replaced simultaneously after changing the mold core in the traditional process, further improving the integration of the equipment and the continuity of the process.

[0031] D. The present invention also achieves the good effect of "single-sided welding and double-sided forming" by using pure nitrogen gas in the groove to protect the back side of the stainless steel sheet joint during welding, preventing it from being oxidized at high temperature.

[0032] E. This invention also effectively protects the electric arc and molten pool (i.e., the metal melting and forming the weld) generated during welding from contamination by oxygen and nitrogen in the air by using a mixture of argon (90%-95%) and nitrogen (5%-10%) in the protective shell. This ensures a stable welding process and good weld quality. At the same time, by precisely controlling the nitrogen content at 5%-10%, the necessary nitrogen element can be supplemented to the weld metal. As a strong austenite-forming element, nitrogen can effectively promote the reformation and stabilization of austenite in the weld metal during cooling, so that the final austenite / ferrite ratio of the weld is restored to a level close to that of the base metal. This ensures that the welded joint has corrosion resistance and mechanical properties comparable to the base metal. Furthermore, this gas protection process, combined with precisely controlled welding heat input parameters, ensures that the microstructure and corrosion resistance of the welded joint of duplex stainless steel sheet meet the application requirements. Attached Figure Description

[0033] Figure 1 This is a first three-dimensional structural schematic diagram of a dual-phase stainless steel sheet welding device described in this application;

[0034] Figure 2 This is a second perspective sectional view of a duplex stainless steel sheet welding apparatus described in this application;

[0035] Figure 3 This is a left view of a welding apparatus for duplex stainless steel sheets as described in this application;

[0036] Figure 4 This is a first partial sectional view of a welding apparatus for duplex stainless steel sheets as described in this application;

[0037] Figure 5 This is a second partial sectional view of a duplex stainless steel sheet welding apparatus described in this application;

[0038] Figure 6 This is a partial structural schematic diagram of the pressing mechanism and the moving mechanism of the duplex stainless steel sheet welding device described in this application;

[0039] Figure 7 This is an enlarged view of section A of the duplex stainless steel sheet welding apparatus described in this application;

[0040] Figure 8 This is a diagram showing the state of a cylindrical tube in a duplex stainless steel sheet welding apparatus as described in this application.

[0041] Figure 9 This is a third partial sectional view of a duplex stainless steel sheet welding apparatus described in this application;

[0042] Figure 10 This is an enlarged view of section B of the duplex stainless steel sheet welding apparatus described in this application;

[0043] Figure 11 This is a partial sectional view of the welding mechanism of the duplex stainless steel sheet welding apparatus described in this application;

[0044] Figure 12 This is an enlarged view of section C of the duplex stainless steel sheet welding apparatus described in this application.

[0045] Explanation of reference numerals in the attached drawings: 1-Base frame, 2-Mounting plate, 3-First electric push rod, 4-Cylindrical tube, 4a-Groove, 5-Fixing rod, 6-Cross, 7-Electromagnet, 8-Inlet pipe, 9-Outlet pipe, 21-First electric slide rail, 22-First electric slider, 23-Support plate, 24-Hydraulic cylinder, 25-Pressing plate, 25a-Arc surface, 31-Second electric slide rail, 32-Second electric slider, 33-Second electric push rod, 34-Fixing plate, 35-Electric suction cup, 41-Evacuation pipe, 42-Inlet pipe, 43-Airbag, 44-Fixing tube, 51-Bracket, 52-Third electric slide rail, 53-Third electric slider, 54-Third electric push rod, 55-Welding torch, 56-Fourth electric push rod, 57-L-shaped plate, 58-Protective shell, 59-Outlet pipe, 60-First conveying pipe, 61-Second conveying pipe, 62-Rubber strip. Detailed Implementation

[0046] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0047] To simplify the disclosure of this invention, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this invention, but those skilled in the art will recognize the application of other processes and / or the use of other materials. Example

[0048] A welding apparatus for duplex stainless steel sheets, such as Figure 1-8 As shown, it includes a base frame 1, on which a mounting plate 2 is fixedly connected;

[0049] A first electric push rod 3 is fixedly connected to the mounting plate 2. The telescopic end of the first electric push rod 3 is equipped with a multi-stage telescopic mechanism, which is composed of multiple iron cylindrical tubes 4. The multiple cylindrical tubes 4 adopt a concentric nested telescopic design, and their diameters decrease from the outermost layer to the innermost layer. A fixing rod 5 is fixedly connected to the mounting plate 2, and a cross 6 is fixedly connected to the fixing rod 5. The cross 6 is fixedly connected to the innermost cylindrical tube 4, and an electromagnet 7 is fixedly connected to the inner ring surface of the cylindrical tube 4.

[0050] A pressing mechanism is connected to the inner wall of the mounting plate 2. The pressing mechanism can press the stainless steel sheet. With the cooperation of the cylindrical tube 4, the stainless steel sheet will be pressed into a cylindrical shape. A welding mechanism is connected to the mounting plate 2. The welding mechanism can weld the joints of the cylindrical stainless steel sheet.

[0051] The cylindrical tube 4 has a cavity inside for containing coolant, and the cavity on the cylindrical tube 4 is connected to the inlet pipe 8 and the outlet pipe 9.

[0052] The pressing mechanism includes an electric slide rail 21 fixedly connected to the inner wall of the mounting plate 2, a first electric slider 22 slidably connected to the electric slide rail 21, a support plate 23 fixedly connected to the first electric slider 22, a hydraulic cylinder 24 fixedly connected to the support plate 23, and a pressing plate 25 fixedly connected to the telescopic part of the hydraulic cylinder 24.

[0053] One side of the pressing plate 25 is set as an arc surface 25a.

[0054] It also includes a moving mechanism, which is connected to the base frame 1. A second electric push rod 33 is fixedly connected to the moving mechanism, and a fixed plate 34 is fixedly connected to the telescopic part of the second electric push rod 33.

[0055] When using this duplex stainless steel sheet welding device, in the initial state, the electromagnet 7 is energized, generating magnetic force to attract and fix multiple iron cylindrical tubes 4, so as to maintain a stable nested structure. The inlet pipe 8 and the outlet pipe 9 are connected to an external pump through flexible hoses for coolant circulation.

[0056] Next, when it is necessary to press the stainless steel sheet into a large-diameter cylindrical shape, the external transfer device is controlled to accurately place the sheet on the two pressing plates 25. Then, the first electric slider 22 is controlled to slide upward on the first electric slide rail 21. The support plate 23, hydraulic cylinder 24, pressing plate 25 and stainless steel sheet move synchronously with the first electric slider 22. Then, the stainless steel sheet will contact the bottom of the outermost cylindrical tube 4. Next, the second electric push rod 33 is controlled to move the fixing plate 34 upward. The fixing plate 34 will contact the stainless steel sheet and firmly press the stainless steel sheet against the cylindrical tube 4. This avoids the stainless steel sheet from moving on the cylindrical tube 4 after being pressed into a cylindrical shape by the pressing plate 25, which would cause a deviation between the joint and the weld of the rolled stainless steel sheet.

[0057] As the pressing plate 25 continues to move upward, it will compress the stainless steel sheet. During this process, the telescopic part of the hydraulic cylinder 24 retracts, allowing the pressing plate 25 to move along the outer circumference of the cylindrical tube 4, gradually pressing the stainless steel sheet into a cylindrical shape. Figure 3 As shown, by setting one side of the pressing plate 25 as an arc surface 25a, when the arc surface 25a on the pressing plate 25 contacts and presses the stainless steel sheet, it effectively avoids the pressing plate 25 from scratching the surface of the stainless steel sheet. In this way, the pressing plate 25 will press the two ends of the rolled stainless steel sheet joint, so that the two ends of the joint are attached to the surface of the cylindrical tube 4, thereby avoiding the two ends of the stainless steel sheet joint from warping outward due to the elasticity of the stainless steel sheet itself, which would cause the joint of the stainless steel sheet to have openings and misalignment at the joint of the rolled stainless steel sheet, thus affecting the subsequent welding quality.

[0058] It should be noted that during the rolling process of the stainless steel sheet, an external pump is simultaneously controlled to deliver coolant to the cavity in the cylindrical tube 4 through a hose and an inlet pipe 8. After the cavity is filled with coolant, the external pump is controlled to extract the coolant from the cavity through a hose and an outlet pipe 9, so that the coolant in the cavity is in a flowing state. Therefore, when the welding mechanism welds the joint of the rolled stainless steel sheet, the heat generated by the stainless steel sheet will be transferred to the cylindrical tube 4, and the heat of the cylindrical tube 4 will be carried away by the coolant. In this way, the cylindrical tube 4 can continuously perform heat transfer treatment on the stainless steel sheet, so that the stainless steel sheet is effectively cooled, thereby achieving an active heat dissipation effect on the welding area and effectively suppressing the thermal deformation of the sheet.

[0059] Next, when it is necessary to press the stainless steel sheet into a small-to-medium diameter cylindrical shape, the electromagnet 7 on the outermost cylindrical tube 4 is de-energized. The electromagnet 7 loses its magnetic attraction to the middle cylindrical tube 4. Then, the telescopic part of the first electric push rod 3 retracts, causing the outermost cylindrical tube 4 to move to the left. The corresponding electromagnet 7, inlet pipe 8, and outlet pipe 9 move synchronously with the cylindrical tube 4, causing the middle cylindrical tube 4 to leak out. Figure 8 As shown in the left figure, it should be noted that during the movement of the outermost cylindrical tube 4, the electromagnet 7 on the middle cylindrical tube 4 is still energized, while the innermost cylindrical tube 4 is fixed by the cross 6. Therefore, during the movement of the outermost cylindrical tube 4, the outermost cylindrical tube 4 will not cause the middle cylindrical tube 4 to move, thus ensuring the accuracy of the position of the middle cylindrical tube 4. Then, repeat the above pressing steps to complete the pressing of the stainless steel sheet into a cylindrical shape with a small to medium diameter.

[0060] When it is necessary to press a stainless steel sheet into a small-diameter cylindrical shape, the electromagnet 7 on the middle layer cylindrical tube 4 is de-energized. The electromagnet 7 loses its magnetic attraction to the innermost cylindrical tube 4. Then, the telescopic part of the first electric push rod 3 retracts, causing the outermost and middle layer cylindrical tubes 4 to move to the left. The corresponding electromagnet 7, inlet pipe 8, and outlet pipe 9 move synchronously with the cylindrical tube 4, causing the innermost cylindrical tube 4 to leak out. Figure 8 As shown in the right figure;

[0061] Thus, through the above-mentioned design of a cylindrical tube 4 with a multi-level concentric nested iron structure and integrated electromagnetic locking and cooling cavity, the device has achieved a significant improvement in function and performance. This design drives the cylindrical tubes 4 at each level to perform axial telescopic movement through the first electric push rod 3, and with the on / off circuit control of the electromagnet 7, it achieves rapid and accurate adaptation to multiple diameter specifications with a single mold core. This effectively solves the problems of work interruption, high labor intensity and low production efficiency caused by the need to replace the entire mold core every time a different diameter cylinder is processed in the prior art. At the same time, through the synergistic action of the hydraulic cylinder 24 and the arc-shaped pressing plate 25, the pressing plate 25 can adapt to the contour of cylindrical tubes 4 with different outer diameters and make stable contour-following movements along its outer ring surface, gradually pressing the stainless steel sheet into a cylindrical shape. This structure enhances the adaptability to forming workpieces of different diameters and solves the problem that the corresponding extrusion equipment must be adjusted or replaced simultaneously after changing the mold core in the traditional process, further improving the integration of the equipment and the continuity of the process. Example

[0062] Based on Example 1, such as Figure 9-12As shown, a groove 4a is provided on the cylindrical tube 4, and an air extraction pipe 41 and an air inlet pipe 42 pass through the cylindrical tube 4. The port of the air extraction pipe 41 is located at the rightmost end of the groove 4a. An air bag 43 is fixedly connected in the groove 4a, and a fixing pipe 44 is connected to the air bag 43. The fixing pipe 44 is connected to the air inlet pipe 42.

[0063] The welding mechanism includes a bracket 51 fixedly connected to the mounting plate 2, a third electric slide rail 52 fixedly connected to the bracket 51, a third electric slider 53 slidably connected to the third electric slide rail 52, a third electric push rod 54 fixedly connected to the third electric slider 53, and a welding torch 55 fixedly connected to the telescopic part of the third electric push rod 54.

[0064] The welding mechanism also includes a fourth electric push rod 56 fixedly connected to the bracket 51. An L-shaped plate 57 is fixedly connected to the telescopic part of the fourth electric push rod 56. A protective shell 58 is fixedly connected to the L-shaped plate 57. The protective shell 58 is made of rubber. An air outlet pipe 59 is fixedly connected to the right end of the protective shell 58. A first conveying pipe 60 and a second conveying pipe 61 are fixedly connected to the left end of the protective shell 58. A rubber strip 62 is provided on the top of the protective shell 58. The rubber strip 62 is made of high-temperature resistant material.

[0065] It should be noted that the air extraction pipe 41, air inlet pipe 42, air outlet pipe 59, first delivery pipe 60 and second delivery pipe 61 are all connected to the external pump via flexible hoses.

[0066] Next, after the stainless steel sheet is rolled into a circle, the seam of the rolled stainless steel sheet will be located at the groove 4a on the cylindrical tube 4. Then, the external pump is controlled to deliver pure nitrogen into the groove 4a through the hose and the air inlet pipe 42. During this process, some nitrogen will enter the airbag 43 through the fixed pipe 44, causing the airbag 43 to expand slightly. The expanded airbag 43 will seal the gap between the groove 4a and the cylindrical stainless steel sheet, forming a closed space between the groove 4a and the cylindrical stainless steel sheet to prevent oxygen from entering. At the same time, the external pump is controlled to extract the air from the groove 4a through the hose and the air extraction pipe 41, so that the groove 4a contains pure nitrogen. Thus, when welding at the stainless steel sheet seam, the pure nitrogen in the groove 4a can protect the back of the stainless steel sheet seam, preventing it from being oxidized at high temperatures, achieving the good effect of "single-sided welding and double-sided forming".

[0067] Meanwhile, the specific steps for welding the stainless steel sheet joints are as follows: Control the third electric push rod 54 to move the welding torch 55 towards the stainless steel sheet joint. Simultaneously, control the fourth electric push rod 56 to lower the L-shaped plate 57. The protective shell 58, air outlet pipe 59, first delivery pipe 60, second delivery pipe 61, and rubber strip 62 move down synchronously with the L-shaped plate 57. The welding head of the welding torch 55 will then contact the stainless steel sheet joint. Since the protective shell 58 is made of rubber, its lower surface will be in close contact with the surface of the stainless steel sheet. The two ends of the protective shell 58 are secured to the edges of the cylindrical stainless steel sheet, creating a sealed space between the protective shell 58, rubber strip 62, and the stainless steel sheet. Next, control the external pump to extract air from this space through the hose and air outlet pipe 59. Simultaneously, control the external pump to supply argon gas (90%-95%) into this space through the hose and second delivery pipe 61. A nitrogen (5%-10%) mixture is introduced to accelerate the expulsion of air from the space. After a short period of time, the air in the space will be completely expelled. At this point, the pump on the exhaust pipe 59 will be shut off. Then, the third electric slider 53 can be controlled to move to the right on the third electric slide rail 52. The third electric push rod 54 and the welding torch 55 move synchronously with the third electric slider 53. During this process, the welding torch 55 is simultaneously controlled to weld the stainless steel sheet joint. Furthermore, during welding, argon (90%-95%) gas is introduced from inside the protective shell 58. The nitrogen (5%-10%) mixture effectively protects the electric arc and molten pool (i.e., the metal melting and forming the weld) generated during welding from contamination by oxygen and nitrogen in the air, ensuring a stable welding process and good weld quality. At the same time, by precisely controlling the nitrogen content at 5%-10%, the weld metal can be supplemented with the necessary nitrogen element. As a strong austenite forming element, nitrogen can effectively promote the reformation and stabilization of austenite in the weld metal during the cooling process, so that the final austenite / ferrite ratio of the weld is restored to a level close to that of the base metal. This ensures that the welded joint has corrosion resistance and mechanical properties comparable to the base metal. Moreover, this gas protection process, combined with the precise control of welding heat input parameters, ensures that the microstructure and corrosion resistance of the welded joint of duplex stainless steel thin plate meet the application requirements.

[0068] It should be noted that during the movement of the welding torch 55, the rubber strip 62 has a corresponding deformation capability. Therefore, the moving welding torch 55 will force the rubber strip 62 around it to undergo concave deformation. The deformed rubber strip 62 is always wrapped around the welding head of the welding torch 55, thereby avoiding the gap between the welding torch 55 and the rubber strip 62, which would allow air to enter the protective shell 58 through the gap and affect the welding process.

[0069] After the stainless steel sheet joint is welded, the external pump is controlled to extract all the mixed gas inside the protective shell 58 through the hose and the exhaust pipe 59. Then the pump on the exhaust pipe 59 is turned off. Next, the external pump is controlled to deliver pure nitrogen into the protective shell 58 through the hose and the first delivery pipe 60, so that the nitrogen fills the entire space inside the protective shell 58. In this way, the pure nitrogen protects the front side of the stainless steel sheet joint and prevents it from being oxidized at high temperatures. Example

[0070] Based on Example 2, such as Figure 7 As shown, the moving mechanism includes a second electric slide rail 31 fixedly connected to the base frame 1, a second electric slider 32 slidably connected to the second electric slide rail 31, the second electric slider 32 being fixedly connected to the second electric push rod 33, and an electric suction cup 35 fixedly connected inside the fixed plate 34.

[0071] A welding process for duplex stainless steel sheets, the specific steps of which are as follows:

[0072] S1. Preparation and positioning: Place the duplex stainless steel sheet on the pressing plate 25 through the external transfer device, control the first electric slider 22 to move upward along the first electric slide rail 21, so that the sheet contacts the outer wall of the outermost cylindrical tube 4; then control the second electric push rod 33 to drive the fixing plate 34 to move upward, and the fixing plate 34 will adsorb and press the sheet against the surface of the cylindrical tube 4.

[0073] S2, Rolling and forming: Start the hydraulic cylinder 24 to drive the pressing plate 25 with the arc surface 25a to move along the outer ring surface of the cylindrical tube 4 to gradually press the stainless steel sheet into a cylindrical shape and ensure that the two ends of its joint are tightly fitted.

[0074] S3. Diameter adjustment: If it is necessary to process small and medium diameter cylinders, control the corresponding level of electromagnet 7 to de-energize and drive the first electric push rod 3 to retract, so that the outermost cylindrical tube 4 moves axially and exposes the working surface of the mold core of the target diameter. Repeat step S2 to complete the rolling.

[0075] S4. Back gas protection: After rolling, the seam is aligned with the groove 4a; pure nitrogen is introduced into the groove 4a through the air inlet pipe 42, and the airbag 43 is expanded to seal the gap between the groove 4a and the cylindrical stainless steel sheet. At the same time, the air in the groove is replaced with pure nitrogen through the air extraction pipe 41 to form a back protective environment.

[0076] S5. Welding protection preparation: Control the fourth electric push rod 56 to drive the protective shell 58 to move down, so that a sealed space is formed between the protective shell 58, the rubber strip 62 and the stainless steel sheet; then exhaust the air in the space through the air outlet pipe 59, and introduce a mixed protective gas composed of 90%-95% argon and 5%-10% nitrogen through the second delivery pipe 61.

[0077] S6. Welding execution: Start the welding torch 55 and control the third electric slider 53 to move at a constant speed along the third electric slide rail 52 to weld the butt joint.

[0078] S7. Post-weld front protection: After welding is completed, the mixed gas inside the protective shell 58 is discharged, and pure nitrogen is introduced into the shell through the first delivery pipe 60 to provide front protection for the high-temperature weld.

[0079] S8. Demolding: When it is necessary to remove the cylindrical stainless steel sheet from the cylindrical tube 4, control the second electric push rod 33 to move the fixing plate 34 down so that the fixing plate 34 is no longer pressing against the stainless steel sheet. Then control the second electric slider 32 to slide to the right on the second electric slide rail 31, so that the cylindrical stainless steel sheet will separate from the cylindrical tube 4. Then, it can be removed from the electric suction cup 35 by the worker or electric clamp.

[0080] It should be noted that, in the initial state, the suction head of the electric suction cup 35 extends from the upper end of the fixing plate 34, so that the suction head of the electric suction cup 35 can subsequently adsorb the cylindrical stainless steel sheet. Then, when the fixing plate 34 firmly presses the stainless steel sheet against the cylindrical tube 4, the suction head of the electric suction cup 35 will retract downward. At this time, the suction head of the electric suction cup 35 will contact the stainless steel sheet and adsorb and fix it. Thus, after the joint of the stainless steel sheet is welded, when it is necessary to remove it from the cylindrical tube 4... When removing the column tube 4, control the second electric push rod 33 to move the fixing plate 34 down, so that the fixing plate 34 is no longer pressing against the stainless steel plate. Then control the second electric slider 32 to slide to the right on the second electric slide rail 31. The second electric push rod 33, the fixing plate 34, the electric suction cup 35 and the cylindrical stainless steel plate move synchronously with the second electric slider 32. Then the cylindrical stainless steel plate will detach from the column tube 4. Then it can be removed from the electric suction cup 35 by the worker or electric clamp.

[0081] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows for communication; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0082] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

Claims

1. A welding apparatus for duplex stainless steel sheets, characterized in that, Includes a base frame (1), on which a mounting plate (2) is fixedly connected; A first electric push rod (3) is fixedly connected to the mounting plate (2). The telescopic end of the first electric push rod (3) is provided with a multi-stage telescopic mechanism, which is composed of multiple iron cylindrical tubes (4). The multiple cylindrical tubes (4) adopt a concentric nested telescopic design, and their diameter decreases from the outermost layer to the innermost layer. A fixing rod (5) is fixedly connected to the mounting plate (2). A cross (6) is fixedly connected to the fixing rod (5). The cross (6) is fixedly connected to the innermost cylindrical tube (4). An electromagnet (7) is fixedly connected to the inner ring surface of the cylindrical tube (4). A pressing mechanism is connected to the inner wall of the mounting plate (2). The pressing mechanism includes an electric slide rail (21) fixed to the inner wall of the mounting plate (2). A first electric slider (22) is slidably connected to the electric slide rail (21). A support plate (23) is fixed to the first electric slider (22). A hydraulic cylinder (24) is fixed to the support plate (23). A pressing plate (25) is fixed to the telescopic part of the hydraulic cylinder (24). With the cooperation of the cylindrical tube (4), the stainless steel sheet is pressed into a cylindrical shape by the pressing plate (25). A welding mechanism is connected to the mounting plate (2). The welding mechanism can weld the joint of the cylindrical stainless steel sheet.

2. The duplex stainless steel sheet welding apparatus according to claim 1, characterized in that, The cylindrical tube (4) has a cavity inside for containing coolant, and the cavity on the cylindrical tube (4) is connected to the inlet pipe (8) and the outlet pipe (9).

3. The duplex stainless steel sheet welding apparatus according to claim 1, characterized in that, One side of the pressing plate (25) is set as an arc surface (25a).

4. The duplex stainless steel sheet welding apparatus according to claim 1, characterized in that, It also includes a moving mechanism, on which the base frame (1) is connected, and a second electric push rod (33) is fixedly connected to the moving mechanism. The telescopic part of the second electric push rod (33) is fixedly connected to a fixing plate (34).

5. The welding apparatus for duplex stainless steel sheets according to claim 1, characterized in that, The cylindrical tube (4) has a groove (4a) and an air extraction pipe (41) and an air inlet pipe (42) pass through it. The port of the air extraction pipe (41) is located at the rightmost end of the groove (4a). An air bag (43) is fixedly connected in the groove (4a). A fixing pipe (44) is connected to the air bag (43). The fixing pipe (44) is connected to the air inlet pipe (42).

6. The duplex stainless steel sheet welding apparatus according to claim 1, characterized in that, The welding mechanism includes a bracket (51) fixedly connected to the mounting plate (2), a third electric slide rail (52) fixedly connected to the bracket (51), a third electric slider (53) slidably connected to the third electric slide rail (52), a third electric push rod (54) fixedly connected to the third electric slider (53), and a welding gun (55) fixedly connected to the telescopic part of the third electric push rod (54).

7. The welding apparatus for duplex stainless steel sheets according to claim 6, characterized in that, The welding mechanism also includes a fourth electric push rod (56) fixedly connected to the bracket (51). The telescopic part of the fourth electric push rod (56) is fixedly connected to an L-shaped plate (57). A protective shell (58) is fixedly connected to the L-shaped plate (57). The protective shell (58) is made of rubber. An air outlet pipe (59) is fixedly connected to the right end of the protective shell (58). A first conveying pipe (60) and a second conveying pipe (61) are fixedly connected to the left end of the protective shell (58). A rubber strip (62) is provided on the top of the protective shell (58). The rubber strip (62) is made of high-temperature resistant material.

8. The welding apparatus for duplex stainless steel sheets according to claim 4, characterized in that, The moving mechanism includes a second electric slide rail (31) fixedly connected to the base frame (1), a second electric slider (32) slidably connected on the second electric slide rail (31), the second electric slider (32) being fixedly connected to the second electric push rod (33), and an electric suction cup (35) fixedly connected inside the fixed plate (34).

9. A welding process for duplex stainless steel sheets, using the welding apparatus for duplex stainless steel sheets as described in claim 8, characterized in that, The specific steps are as follows: S1. Preparation and positioning: Place the duplex stainless steel sheet on the pressing plate (25) through the external transfer device, control the first electric slider (22) to move upward along the first electric slide rail (21) so that the sheet contacts the outer wall of the outermost cylindrical tube (4); then control the second electric push rod (33) to drive the fixing plate (34) to move upward, and the fixing plate (34) will adsorb and press the sheet against the surface of the cylindrical tube (4); S2, Rolling and forming: Start the hydraulic cylinder (24) and drive the pressing plate (25) with the arc surface (25a) to move along the outer ring surface of the cylindrical tube (4) to gradually press the stainless steel sheet into a cylindrical shape and ensure that the two ends of its joint are tightly fitted. S3. Diameter adjustment: If it is necessary to process small and medium diameter cylinders, control the electromagnet (7) of the corresponding level to de-energize and drive the first electric push rod (3) to retract, so that the outermost cylindrical tube (4) moves axially and exposes the working surface of the mold core of the target diameter. Repeat step S2 to complete the rolling. S4. Back gas protection: After rolling, the seam is aligned with the groove (4a); pure nitrogen gas is introduced into the groove (4a) through the air inlet pipe (42), and the airbag (43) is expanded to seal the gap between the groove (4a) and the cylindrical stainless steel sheet. At the same time, the air in the groove is replaced with pure nitrogen gas through the air extraction pipe (41) to form a back protective environment. S5. Welding protection preparation: Control the fourth electric push rod (56) to drive the protective shell (58) to move down, so that a sealed space is formed between the protective shell (58), the rubber strip (62) and the stainless steel sheet; then exhaust the air in the space through the air outlet pipe (59), and introduce a mixed protective gas composed of 90%-95% argon and 5%-10% nitrogen through the second delivery pipe (61); S6. Welding execution: Start the welding gun (55), control the third electric slider (53) to move at a constant speed along the third electric slide rail (52) to weld the butt joint; S7. Post-weld front protection: After welding is completed, the mixed gas inside the protective shell (58) is discharged, and pure nitrogen is introduced into the shell through the first delivery pipe (60) to provide front protection for the high-temperature weld. S8. Demolding: When it is necessary to remove the cylindrical stainless steel sheet from the cylindrical tube (4), control the second electric push rod (33) to move the fixing plate (34) down so that the fixing plate (34) is no longer pressing against the stainless steel sheet. Then control the second electric slider (32) to slide to the right on the second electric slide rail (31), so that the cylindrical stainless steel sheet will separate from the cylindrical tube (4). Then, the worker or electric clamp can remove it from the electric suction cup (35).

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