A special welding method for sealing surface of high temperature and high pressure valve

Abstract

The present invention provides a special welding method for the sealing surface of a high-temperature and high-pressure valve, belonging to the technical field of welding the sealing surface of a high-temperature and high-pressure valve; it comprises a welding gun and a workbench, the workbench is rotatably connected with a rotating plate, and a splash-proof assembly, the splash-proof assembly is used to prevent the welding liquid from splashing during welding, and the splash-proof assembly comprises a fixed sleeve fixedly sleeved on the outer wall of the welding gun. The present invention uses high-frequency pulses to release high-energy electric energy between an electrode and a metal base material at a high frequency by setting welding parameters, and controls the occurrence of cracks that are prone to occur during the process through artificial control, fully fuses the welding material to the surface layer of the valve core and valve seat, melts and diffuses the ionic welding material into the base material matrix, forms a metallurgical bond, effectively improves the welding effect of the sealing surface of the valve core and valve seat of the high-temperature and high-pressure valve during welding, makes the valve less susceptible to damage during the operation of the unit, improves the service life of the valve, and reduces the maintenance frequency of the valve.

Description

Technical Field

[0001] The invention relates to the technical field of high-temperature and high-pressure valve sealing surface welding, and in particular to a special welding method for high-temperature and high-pressure valve sealing surfaces. Background Art

[0002] As the parameters of large-scale power station units increase, high-temperature and high-pressure equipment also increase. More and more Stellite alloy materials are used on site as the sealing surface of high-temperature and high-pressure valves. Stellite alloy uses cobalt as the main component and contains a considerable amount of nickel, chromium, tungsten and a small amount of molybdenum, niobium, tantalum, titanium and other alloy elements. It has excellent comprehensive properties such as high-temperature oxidation resistance, wear resistance and corrosion resistance. During the operation of the unit, high-temperature and high-pressure valves need to be used to adjust the parameters. Due to the repeated opening and closing of the valve, the combined influence of uncertain factors such as high temperature and high pressure and the violent impact of the valve stem has an impact on it. The valve core and valve seat are prone to cracking or surface wear, which makes it impossible to effectively close the valve, which will affect the safe operation of the unit. In addition, the plasticity and toughness of the Stellite alloy are poor, and longitudinal and radial cracks are prone to occur at the surfacing position. In severe cases, there is a risk of falling off the sealing surface, which will endanger the safety of the unit to a certain extent.

[0003] Large power station units usually use imported valves as an important factor to improve safety when operating at high parameters. When problems occur with the valve core and valve seat, it is impossible to return the valve to the factory for repair in consideration of factors such as time, construction period, and cost. The valve core and valve seat are plated with Stellite alloy and traditional welding methods such as tungsten inert gas arc welding are used. The arc welding has high heat input, large thermal shock to the substrate, wide heat-affected zone, and large deformation of the substrate metal around the molten pool. It is necessary to preheat before welding and control the interlayer temperature, and perform high-temperature heat treatment and slow cooling after welding. Improper operation can easily cause defects to expand and cause The valve core and valve seat cannot be repaired and have reached the scrap condition. The welding materials of the sealing surface of the valve core and valve seat of the high-temperature and high-pressure valve are generally Stellite alloy welding wire and welding rod. Since the weldability of Stellite alloy is very poor and cracks are very easy to appear, the preheating and interlayer temperature must be controlled in a higher temperature range, which brings great difficulties to on-site welding and subsequent processing. Moreover, after a period of operation, the sealing surface will still crack again. The use of other materials to replace Stellite alloy cannot meet the performance requirements of the unit during operation, and cannot ensure the long-term safe operation of the unit.

[0004] In the prior art, when welding the sealing surface of the valve core and valve seat of a high-temperature and high-pressure valve, it is necessary to slowly cool the sealing surface after welding. When cooling down, cracks will usually appear in the welding layer of the sealing surface due to cooling down too quickly, affecting the quality of welding. At the same time, since the welding fluid at high temperature is prone to sputtering, fine pits and metal branches will be generated during welding, which will cause the welding layer to be uneven and affect the use of the sealing surface. Therefore, the present application provides a special welding method for the sealing surface of a high-temperature and high-pressure valve to meet the needs. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a special welding method for the sealing surface of a high-temperature and high-pressure valve to solve the problem that when the existing high-temperature and high-pressure valve sealing surface is made of Stellite alloy, longitudinal and radial cracks are easily generated at the surfacing position during welding. In severe cases, there is a risk of the sealing surface falling off, which endangers the safety of the unit to a certain extent. When problems occur on the sealing surface of the valve core and valve seat, it is difficult to repair. When welding the sealing surface of the valve core and valve seat of the high-temperature and high-pressure valve, it is necessary to cool the sealing surface after welding. When cooling down, cracks will usually appear in the welding layer of the sealing surface due to the too fast cooling, affecting the quality of welding. At the same time, due to the high temperature, the welding fluid is prone to sputtering, which will cause fine pits and metal branches during welding, which will cause the welding layer to be uneven and affect the use of the sealing surface.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] A special welding method for the sealing surface of a high-temperature and high-pressure valve includes the following steps:

[0008] S1. Change welding process and parameters: Based on the argon arc welding method, high-frequency pulses are used to release high-energy electrical energy between the electrode and the metal base material at high frequency. Through artificial control, the occurrence of cracks that are prone to occur during the process is controlled, the welding material is fully melted on the surface layer of the valve core and valve seat, and the ionic welding material is melted and diffused into the base material matrix to form a metallurgical bond;

[0009] S2. Welding repair: Before base welding, preheat the base metal to 350-400℃. During welding, the temperature should be maintained during rapid welding, and the thickness of the weld layer should be strictly controlled. After welding, heat treatment should be performed immediately and slowly cooled to room temperature. Non-destructive testing methods such as penetration should be used to ensure that the welding is qualified. Tungsten electrodes should be used during welding, and 99.99% argon gas should be used as the shielding gas during welding.

[0010] S3. Welding transition: ERNiCrMo-3 welding material is used for material transition, the weld thickness is about 1mm, before base welding, the conventional base metal is preheated to 150-200℃, we adopt the method of increasing the preheating temperature to 350-400℃ and welding with heat, in order to improve the bonding strength between the cladding layer and the base metal, the base welding layer adopts a relatively high welding current for rapid welding;

[0011] S4. Grinding of transition welding layer: Use Stellite6 welding material to weld the high temperature and wear-resistant layer to restore the valve closing surface performance. Perform overall heat treatment after welding and strictly control the cooling speed;

[0012] When the above steps are used to weld the sealing surface of a high-temperature and high-pressure valve, welding equipment is specifically involved, including a welding gun and a workbench, the workbench is rotatably connected with a rotating plate, and a splash-proof assembly, the splash-proof assembly is used to prevent the welding liquid from splashing during welding, the splash-proof assembly includes a fixed sleeve fixedly sleeved on the outer wall of the welding gun, a pair of limit grooves are opened on the fixed sleeve, one of the limit grooves is slidably connected to a limit rod, one end of the limit rod is fixedly connected to a first mounting plate, the first mounting plate is fixedly connected to a second mounting plate by a fixing screw, the welding gun is arranged at a middle position between the first mounting plate and the second mounting plate, the other end of the limit rod is fixedly connected to a baffle, the bottom of the inner wall of the baffle is fixedly connected to a collection box, and a slow cooling assembly, the slow cooling assembly is used to prevent the weldment from cooling down too quickly after welding.

[0013] Preferably, the baffle is made of a high temperature resistant material.

[0014] Preferably, the first mounting plate and the second mounting plate are both in an arc-shaped structure.

[0015] Preferably, the baffle is in a fan-shaped structure.

[0016] Preferably, the slow cooling component includes a limit plate sleeved on the rotating plate, the welding part is sleeved on the limit plate, a groove is provided on one side of the limit plate, a plurality of springs are fixedly connected to the limit plate, one end of the spring is fixedly connected to a movable plate, the movable plate is slidably connected to the inner wall of the groove, a pair of slots are provided on the inner wall of the limit plate, each of the slots is clamped with an elastic sheet, the top of a pair of elastic sheets is fixedly connected with the same clamping block, the clamping block is slidably connected to the inner wall of the groove, a heat preservation cover is fixedly connected to one side of the clamping block, and the heat preservation cover covers the outside of the welding part.

[0017] Preferably, the cross-section of the limiting plate is an L-shaped structure.

[0018] Preferably, the elastic sheet is made of elastic metal material, and a heat insulation pad is provided on the surface of the elastic sheet.

[0019] Preferably, the elastic sheet is in an L-shaped structure.

[0020] Preferably, the limiting plate is made of a high temperature resistant material.

[0021] Preferably, the outer surface of the heat-insulating cover is made of heat-insulating material.

[0022] Compared with the prior art, the present invention has at least the following beneficial effects:

[0023] In the above scheme, by setting the welding parameters, high-frequency pulses are used to release high-energy electrical energy at high frequency between the electrode and the metal base material. Through artificial control, the occurrence of cracks that are prone to occur during the process is controlled, the welding material is fully fused to the surface layer of the valve core and valve seat, and the ionic welding material is melted and diffused into the base material matrix to form a metallurgical bond, which effectively improves the welding effect of the sealing surface of the valve core and valve seat of the high-temperature and high-pressure valve during welding, making the valve less susceptible to damage during the operation of the unit, thereby increasing the service life of the valve and reducing the maintenance frequency of the valve.

[0024] Through the welding material repair technology set up, when the sealing surface of the valve cracks during the operation of the unit, the cracks can be repaired. Before the base welding, the base metal is preheated to 350-400℃. During the welding process, the temperature should be maintained for rapid welding, and the thickness of the weld layer should be strictly controlled. After welding, heat treatment should be carried out immediately and slowly cooled to room temperature. Non-destructive testing methods such as penetration are carried out to ensure that the welding is qualified, the transition weld layer is welded, and the transition weld layer is evenly polished, which effectively solves the cracking problem of the Stellite alloy and restores the original performance of the Stellite alloy. The sealing surface cladding layer avoids the occurrence of problems such as cracks or explosions during the entire welding process, saves construction time and cost, innovates construction procedures and quality control, improves the quality of cladding joints, improves long-term safe operation, and also restores the original state and performance of the Stellite alloy surface material, and efficiently repairs and greatly reduces maintenance costs.

[0025] Through the baffle, when welding, use the welding gun to aim at the weldment and weld the weldment. During welding, the welding liquid will splash, and the welding liquid will splash onto the baffle, and will not splash onto the place where it has been welded, effectively avoiding the problem of fine pits and metal branches during welding, improving the flatness of the welding layer, and improving the use effect of the sealing surface of the weldment.

[0026] Through the provided collecting box, the welding liquid splashed onto the inner wall of the baffle can slide along the inner wall of the baffle into the inside of the collecting box. After welding is completed, the fixing screws can be unscrewed to separate the first mounting plate and the second mounting plate. The first mounting plate can be slid upward along the welding gun. When the limiting rod leaves the limiting groove, the first mounting plate, the limiting rod and the baffle can be removed, and the welding liquid in the collecting box can be collected and recycled.

[0027] Through the set limit groove, when in use, the direction of the baffle can be adjusted according to the welding direction, the limit rod is placed in the limit groove, the limit rod is slid downward, and the second mounting plate and the first mounting plate are fixed with fixing screws. Then the welded parts can be welded to achieve the effect of adjusting the direction of the baffle according to needs.

[0028] By setting the limit plate, when in use, the welding part is sleeved on the limit plate, and the limit plate is sleeved on the rotating plate. At this time, under the action of the spring, the outer wall of the movable plate is flush with the outer wall of the limit plate, so that the limit plate is in a closed state. When welding the welding part, the welding liquid will not splash into the groove, and the welding part can be welded with a welding gun. After the welding is completed, the clamping block is clamped in the groove so that the elastic sheet is aligned with the groove position, the elastic sheet is pinched inwardly to make the elastic sheet shrink inwardly, and the clamping block is pressed downward until the elastic sheet is engaged with the clamping groove, so as to realize the installation of the insulation cover, effectively realize the insulation of the welding part, avoid the problem of cracks in the welding layer caused by too fast cooling of the welding part, and improve the welding quality. After removing the entire slow cooling assembly, the slow cooling assembly can be wrapped with asbestos cloth to further improve the slow cooling effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings, which are incorporated herein and constitute a part of the specification, illustrate embodiments of the present disclosure and, together with the description, further serve to explain the principles of the present disclosure and to enable those skilled in the relevant art to make and use the present disclosure.

[0030] Figure 1 A schematic diagram of the three-dimensional structure of the welding gun, splash protection assembly, workbench and slow cooling assembly;

[0031] Figure 2 Schematic diagram of the three-dimensional structure of the welding gun and splash guard assembly;

[0032] Figure 3 A partially cutaway three-dimensional structural schematic diagram of the workbench and slow cooling assembly assembly;

[0033] Figure 4 A schematic diagram of a partially cut-away side view of the workbench and slow cooling assembly assembly;

[0034] Figure 5 for Figure 2 The enlarged structural diagram at A in the middle;

[0035] Figure 6 for Figure 3 The enlarged structural diagram at B in the middle;

[0036] Figure 7 for Figure 4 Enlarged structural diagram at point C in the middle.

[0037] [reference numerals]

[0038] 1. Welding gun; 2. Workbench; 3. Rotating plate; 4. Splash-proof assembly; 5. Slow cooling assembly; 6. Fixed sleeve; 7. Limiting groove; 8. Limiting rod; 9. First mounting plate; 10. Fixing screw; 11. Second mounting plate; 12. Baffle; 13. Collecting box; 14. Limiting plate; 15. Spring; 16. Movable plate; 17. Slot; 18. Elastic sheet; 19. Block; 20. Insulation cover; 21. Welding piece; 22. Groove.

[0039] As shown in the figure, in order to clearly implement the structure of the embodiment of the present invention, specific structures and devices are marked in the figure, but this is only for illustrative purposes and is not intended to limit the present invention to the specific structure, device and environment. According to specific needs, ordinary technicians in this field can adjust or modify these devices and environments, and the adjustments or modifications made are still included in the scope of the attached claims. DETAILED DESCRIPTION

[0040] The following is a detailed description of a special welding method for a high-temperature and high-pressure valve sealing surface provided by the present invention in conjunction with the accompanying drawings and specific embodiments. At the same time, it is explained here that in order to make the embodiments more detailed, the following embodiments are the best and preferred embodiments, and those skilled in the art may also adopt other alternative methods to implement some known technologies; and the accompanying drawings are only for a more specific description of the embodiments, and are not intended to specifically limit the present invention.

[0041] It should be noted that the references to "one embodiment", "an embodiment", "an exemplary embodiment", "some embodiments" and the like in the specification indicate that the embodiments described may include specific features, structures or characteristics, but not every embodiment may include the specific features, structures or characteristics. In addition, when describing specific features, structures or characteristics in conjunction with an embodiment, it should be within the knowledge of technicians in the relevant field to implement such features, structures or characteristics in conjunction with other embodiments.

[0042] In general, a term can be understood, at least in part, from its use in context. For example, depending, at least in part, on the context, the term "one or more" as used herein can be used to describe any feature, structure, or characteristic in the singular sense, or can be used to describe a combination of features, structures, or characteristics in the plural sense. Additionally, the term "based on" can be understood as not necessarily intended to convey an exclusive set of factors, but can instead, depending, at least in part, on the context, allow for the presence of other factors that are not necessarily explicitly described.

[0043] It will be understood that the meaning of “on,” “over,” and “above” in this disclosure should be interpreted in the broadest manner, so that “on” means not only “directly on” something, but also includes the meaning of being “on” something with intervening features or layers therebetween, and “on” or “over” means not only “on” or “above” something, but also includes the meaning of being “on” or “above” something with no intervening features or layers therebetween.

[0044] Additionally, spatially relative terms such as "under," "beneath," "lower," "above," "upper," and the like may be used herein for descriptive convenience to describe the relationship of one element or feature to another element or features, as shown in the accompanying drawings. Spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the accompanying drawings. The device may be oriented in other ways, and the spatially relative descriptors used herein may be similarly interpreted accordingly.

[0045] like Figure 1-7 As shown, an embodiment of the present invention provides a special welding method for a high-temperature and high-pressure valve sealing surface, comprising the following steps:

[0046] S1. Change welding process and parameters: Based on the argon arc welding method, high-frequency pulses are used to release high-energy electrical energy between the electrode and the metal base material at high frequency. Through artificial control, the occurrence of cracks that are prone to occur during the process is controlled, the welding material is fully melted on the surface layer of the valve core and valve seat, and the ionic welding material is melted and diffused into the base material matrix to form a metallurgical bond;

[0047] S2. Welding repair: Before base welding, preheat the base metal to 350-400℃. During welding, the temperature should be maintained during rapid welding, and the thickness of the weld layer should be strictly controlled. After welding, heat treatment should be performed immediately and slowly cooled to room temperature. Non-destructive testing methods such as penetration should be used to ensure that the welding is qualified. Tungsten electrodes should be used during welding, and 99.99% argon gas should be used as the shielding gas during welding.

[0048] S3. Welding transition: ERNiCrMo-3 welding material is used for material transition, the weld thickness is about 1mm, before base welding, the conventional base metal is preheated to 150-200℃, we adopt the method of increasing the preheating temperature to 350-400℃ and welding with heat, in order to improve the bonding strength between the cladding layer and the base metal, the base welding layer adopts a relatively high welding current for rapid welding;

[0049] S4. Grinding of transition welding layer: Use Stellite6 welding material to weld the high temperature and wear-resistant layer to restore the valve closing surface performance. Perform overall heat treatment after welding and strictly control the cooling speed;

[0050] When the above steps are used to weld the sealing surface of a high-temperature and high-pressure valve, welding equipment is specifically involved, including a welding gun 1 and a workbench 2. The welding gun 1 is a prior art and can be used for surfacing welding on a welded part 21. A rotating plate 3 and a splash-proof assembly 4 are rotatably connected to the workbench 2. The splash-proof assembly 4 is used to prevent the welding liquid from splashing during welding. The splash-proof assembly 4 includes a fixed sleeve 6 fixedly sleeved on the outer wall of the welding gun 1. A pair of limit grooves 7 are provided on the fixed sleeve 6, one of which is slidably connected to a limit rod 8. One end of the limit rod 8 is fixedly connected to a first mounting plate 9, and the first mounting plate 9 is fixedly connected to a second mounting plate 11 by a fixing screw 10. The welding gun 1 is arranged at a middle position between the first mounting plate 9 and the second mounting plate 11. The other end of the limit rod 8 is fixedly connected to a baffle 12, and a collection box 13 and a slow cooling assembly 5 are fixedly connected to the bottom of the inner wall of the baffle 12. The slow cooling assembly 5 is used to prevent the welded part 21 from cooling down too quickly after welding.

[0051] By setting the welding parameters, high-frequency pulses are used to release high-energy electrical energy at high frequency between the electrode and the metal base material. Through artificial control, the occurrence of cracks that are prone to occur during the process is controlled, the welding material is fully fused to the surface layer of the valve core and valve seat, and the ionic welding material is melted and diffused into the base material matrix to form a metallurgical bond, which effectively improves the welding effect of the sealing surface of the valve core and valve seat of the high-temperature and high-pressure valve during welding, making the valve less susceptible to damage during the operation of the unit, thereby increasing the service life of the valve and reducing the frequency of valve maintenance.

[0052] Through the welding material repair technology, when the sealing surface of the valve cracks during the operation of the unit, the cracks can be repaired. Before the base welding, the base metal is preheated to 350-400℃. During the welding process, the temperature should be maintained for rapid welding, and the thickness of the weld layer should be strictly controlled. After welding, heat treatment should be carried out immediately, slowly cooled to room temperature, and non-destructive testing methods such as penetration should be carried out to ensure that the welding is qualified, weld the transition weld layer, and evenly grind the transition weld layer, which effectively solves the cracking problem of the Stellite alloy and restores the original performance of the Stellite alloy. The sealing surface cladding layer avoids the occurrence of problems such as cracks or explosions during the entire welding process, saves construction time and cost, innovates construction procedures and quality control, improves the quality of cladding joints, improves long-term safe operation, and also restores the original state and performance of the Stellite alloy surface material, and efficiently repairs and greatly reduces maintenance costs.

[0053] By setting the baffle 12, during welding, the welding gun 1 is used to aim at the welding part 21, and the welding part 21 is welded. During welding, the welding liquid splashes, and the welding liquid splashes onto the baffle 12, and does not splash onto the place where the welding has been done, which effectively avoids the problem of fine pits and metal branches during welding, improves the flatness of the welding layer, and improves the use effect of the sealing surface of the welding part 21.

[0054] Through the provided collecting box 13, the welding liquid splashed onto the inner wall of the baffle 12 can slide along the inner wall of the baffle 12 into the collecting box 13. After welding is completed, the fixing screws 10 can be unscrewed to separate the first mounting plate 9 and the second mounting plate 11. The first mounting plate 9 can be slid upward along the welding gun 1. When the limiting rod 8 leaves the limiting groove 7, the first mounting plate 9, the limiting rod 8 and the baffle 12 can be removed, and the welding liquid in the collecting box 13 can be collected and recycled.

[0055] By setting the limiting groove 7, when in use, the direction of the baffle 12 can be adjusted according to the welding direction, the limiting rod 8 is placed in the limiting groove 7, the limiting rod 8 is slid downward, and the second mounting plate 11 and the first mounting plate 9 are fixed by the fixing screws 10. Then, the welding part 21 can be welded to achieve the effect of adjusting the direction of the baffle 12 as needed.

[0056] In this embodiment, if Figure 2 As shown, the baffle 12 is made of a high temperature resistant material, preferably an aluminum alloy, and the baffle 12 is in a fan-shaped structure, which increases the anti-sputtering area to a certain extent and improves the anti-sputtering effect.

[0057] In this embodiment, if Figure 2 and Figure 5 As shown, the first mounting plate 9 and the second mounting plate 11 are both in an arc-shaped structure, which is compatible with the welding gun 1 and better fixes the first mounting plate 9 and the second mounting plate 11.

[0058] As an implementation method in this embodiment, Figure 1-7 As shown, the slow cooling component 5 includes a limit plate 14 sleeved on the rotating plate 3, and a welding part 21 is sleeved on the limit plate 14. A groove 22 is provided on one side of the limit plate 14. A plurality of springs 15 are fixedly connected to the limit plate 14. One end of the spring 15 is fixedly connected to a movable plate 16. The movable plate 16 is slidably connected to the inner wall of the groove 22. A pair of slots 17 are provided on the inner wall of the limit plate 14. An elastic sheet 18 is clamped on each slot 17. The top of the pair of elastic sheets 18 is fixedly connected to the same clamping block 19. The clamping block 19 is slidably connected to the inner wall of the groove 22. A heat preservation cover 20 is fixedly connected to one side of the clamping block 19. The heat preservation cover 20 covers the outside of the welding part 21.

[0059] By setting the limiting plate 14, when in use, the welding piece 21 is sleeved on the limiting plate 14, and the limiting plate 14 is sleeved on the rotating plate 3. At this time, under the action of the spring 15, the outer wall of the movable plate 16 is flush with the outer wall of the limiting plate 14, so that the limiting plate 14 is in a closed state. When welding the welding piece 21, the welding liquid will not splash into the groove 22. The welding gun 1 can be used to weld the welding piece 21. After the welding is completed, the clamping block 19 clamps the groove 22. The elastic sheet 18 is aligned with the groove 22, and the elastic sheet 18 is pinched inward to shrink inward. The card block 19 is pressed downward until the elastic sheet 18 is engaged with the card groove 17, thereby installing the thermal insulation cover 20. The thermal insulation of the welded part 21 is effectively achieved, and the problem of cracks in the welding layer caused by the welded part 21 cooling down too quickly is avoided, thereby improving the welding quality. After removing the entire slow-cooling component 5, the slow-cooling component 5 can be wrapped with asbestos cloth to further improve the slow-cooling effect.

[0060] In this embodiment, if Figure 3 As shown, the cross-section of the limiting plate 14 is L-shaped, which is convenient for placing the weldment 21 on the limiting plate 14. The limiting plate 14 is made of a high temperature resistant material, preferably an aluminum alloy, to avoid the limiting plate 14 being affected by excessive welding temperature.

[0061] In this embodiment, if Figure 3 and Figure 6 As shown, the elastic sheet 18 is made of elastic metal material, preferably spring steel, so that the elastic sheet 18 is elastic. A heat insulation pad is provided on the surface of the elastic sheet 18 to prevent the elastic sheet 18 from being affected by the surrounding temperature when using it. The elastic sheet 18 is in an L-shaped structure, which is convenient for clamping the elastic sheet 18 with the slot 17 when fixing the insulation cover 20.

[0062] In this embodiment, if Figure 3 As shown, the outer surface of the insulation cover 20 is made of insulation material, specifically aluminum silicate fiberboard. The aluminum silicate fiberboard has low thermal conductivity and can slowly insulate the weld 21, effectively avoiding the influence of too fast cooling speed on the welding layer of the weld 21.

[0063] The technical solution provided by the present invention, through the set welding parameters, utilizes high-frequency pulses to release high-energy electrical energy at high frequency between the electrode and the metal base material, and through artificial control, the occurrence of cracks that are prone to occur in the process is controlled, the welding material is fully fused to the surface layer of the valve core and valve seat, and the ionic welding material is melted and diffused into the base material matrix to form a metallurgical bond, which effectively improves the welding effect of the sealing surface of the valve core and valve seat of the high-temperature and high-pressure valve during welding, makes the valve less susceptible to damage during the operation of the unit, improves the service life of the valve, and reduces the maintenance frequency of the valve.

[0064] Through the welding material repair technology, when the sealing surface of the valve cracks during the operation of the unit, the cracks can be repaired. Before the base welding, the base metal is preheated to 350-400℃. During the welding process, the temperature should be maintained for rapid welding, and the thickness of the weld layer should be strictly controlled. After welding, heat treatment should be carried out immediately, slowly cooled to room temperature, and non-destructive testing methods such as penetration should be carried out to ensure that the welding is qualified, weld the transition weld layer, and evenly grind the transition weld layer, which effectively solves the cracking problem of the Stellite alloy and restores the original performance of the Stellite alloy. The sealing surface cladding layer avoids the occurrence of problems such as cracks or explosions during the entire welding process, saves construction time and cost, innovates construction procedures and quality control, improves the quality of cladding joints, improves long-term safe operation, and also restores the original state and performance of the Stellite alloy surface material, and efficiently repairs and greatly reduces maintenance costs.

[0065] Through the baffle, when welding, use the welding gun to aim at the weldment and weld the weldment. During welding, the welding liquid will splash, and the welding liquid will splash onto the baffle, and will not splash onto the place where it has been welded, effectively avoiding the problem of fine pits and metal branches during welding, improving the flatness of the welding layer, and improving the use effect of the sealing surface of the weldment.

[0066] Through the provided collecting box, the welding liquid splashed onto the inner wall of the baffle can slide along the inner wall of the baffle into the inside of the collecting box. After welding is completed, the fixing screws can be unscrewed to separate the first mounting plate and the second mounting plate. The first mounting plate can be slid upward along the welding gun. When the limiting rod leaves the limiting groove, the first mounting plate, the limiting rod and the baffle can be removed, and the welding liquid in the collecting box can be collected and recycled.

[0067] Through the set limit groove, when in use, the direction of the baffle can be adjusted according to the welding direction, the limit rod is placed in the limit groove, the limit rod is slid downward, and the second mounting plate and the first mounting plate are fixed with fixing screws. Then the welded parts can be welded to achieve the effect of adjusting the direction of the baffle according to needs.

[0068] By setting the limit plate, when in use, the welding part is sleeved on the limit plate, and the limit plate is sleeved on the rotating plate. At this time, under the action of the spring, the outer wall of the movable plate is flush with the outer wall of the limit plate, so that the limit plate is in a closed state. When welding the welding part, the welding liquid will not splash into the groove, and the welding part can be welded with a welding gun. After the welding is completed, the clamping block is clamped in the groove so that the elastic sheet is aligned with the groove position, the elastic sheet is pinched inwardly to make the elastic sheet shrink inwardly, and the clamping block is pressed downward until the elastic sheet is engaged with the clamping groove, so as to realize the installation of the insulation cover, effectively realize the insulation of the welding part, avoid the problem of cracks in the welding layer caused by too fast cooling of the welding part, and improve the welding quality. After removing the entire slow cooling assembly, the slow cooling assembly can be wrapped with asbestos cloth to further improve the slow cooling effect.

[0069] The present invention covers any substitution, modification, equivalent method and scheme made on the essence and scope of the present invention. In order to make the public have a thorough understanding of the present invention, specific details are described in detail in the following preferred embodiments of the present invention, but those skilled in the art can fully understand the present invention without the description of these details. In addition, in order to avoid unnecessary confusion about the essence of the present invention, well-known methods, processes, procedures, components and circuits are not described in detail.

[0070] A person skilled in the art will appreciate that all or part of the steps in the above-mentioned embodiment method can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc.

[0071] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A special welding method for the sealing surface of a high-temperature and high-pressure valve, characterized in that: The steps include: S1. Change welding process and parameters: Based on the argon arc welding method, high-frequency pulses are used to release high-energy electrical energy between the electrode and the metal base material at high frequency. Through artificial control, the occurrence of cracks that are prone to occur during the process is controlled, the welding material is fully melted on the surface layer of the valve core and valve seat, and the ionic welding material is melted and diffused into the base material matrix to form a metallurgical bond; S2. Welding repair: Before base welding, preheat the base metal to 350-400℃. During welding, the temperature should be maintained and the welding should be performed quickly. The thickness of the welding layer should be strictly controlled. After welding, heat treatment should be performed immediately, and the temperature should be slowly lowered to room temperature. Penetrant non-destructive testing should be performed to ensure that the welding is qualified. Tungsten electrodes should be used during welding, and 99.99% argon gas should be used as the shielding gas during welding. S3. Welding transition: ERNiCrMo-3 welding material is used for material transition, the weld thickness is 1mm, before base welding, the conventional base metal is preheated to 150-200℃, the preheating temperature is increased to 350-400℃ and heat welding is performed, in order to improve the bonding strength between the cladding layer and the base metal, the base welding layer is welded quickly with a relatively high welding current; S4. Grinding of transition welding layer: Use Stellite6 welding material to weld the high temperature and wear-resistant layer to restore the valve closing surface performance. Perform overall heat treatment after welding and strictly control the cooling speed; When the above steps are used to weld the sealing surface of a high-temperature and high-pressure valve, welding equipment is also involved, including a welding gun and a workbench, and a rotating plate is rotatably connected to the workbench; A splash-proof assembly, the splash-proof assembly is used to prevent the welding liquid from splashing during welding, the splash-proof assembly includes a fixed sleeve fixedly sleeved on the outer wall of the welding gun, a pair of limit grooves are provided on the fixed sleeve, a limit rod is slidably connected to one of the limit grooves, one end of the limit rod is fixedly connected to a first mounting plate, the first mounting plate is fixedly connected to a second mounting plate by a fixing screw, the welding gun is arranged at a middle position between the first mounting plate and the second mounting plate, the other end of the limit rod is fixedly connected to a baffle, and a collection box is fixedly connected to the bottom of the inner wall of the baffle; A slow cooling component, which is used to prevent the welding parts from cooling down too quickly after welding; The slow cooling component includes a limit plate sleeved on the rotating plate, the welding part is sleeved on the limit plate, a groove is provided on one side of the limit plate, a plurality of springs are fixedly connected to the limit plate, one end of the spring is fixedly connected to a movable plate, the movable plate is slidably connected to the inner wall of the groove, a pair of slots is provided on the inner wall of the limit plate, each of the slots is clamped with an elastic sheet, the tops of the pair of elastic sheets are fixedly connected with the same clamping block, the clamping block is slidably connected to the inner wall of the groove, a heat preservation cover is fixedly connected to one side of the clamping block, and the heat preservation cover covers the outside of the welding part.

2. The special welding method for the sealing surface of a high-temperature and high-pressure valve according to claim 1 is characterized in that: The baffle is made of a high temperature resistant material.

3. The special welding method for the sealing surface of a high-temperature and high-pressure valve according to claim 1 is characterized in that: The first mounting plate and the second mounting plate are both in an arc-shaped structure.

4. The special welding method for sealing surface of high temperature and high pressure valve according to claim 1 is characterized in that: The baffle is in a fan-shaped structure.

5. The special welding method for the sealing surface of a high-temperature and high-pressure valve according to claim 1 is characterized in that: The cross section of the limiting plate is an L-shaped structure.

6. The special welding method for the sealing surface of a high-temperature and high-pressure valve according to claim 1 is characterized in that: The elastic sheet is made of elastic metal material, and a heat insulation pad is arranged on the surface of the elastic sheet.

7. The special welding method for sealing surface of high temperature and high pressure valve according to claim 1 is characterized in that: The elastic sheet is in an L-shaped structure.

8. The special welding method for sealing surface of high temperature and high pressure valve according to claim 1 is characterized in that: The material of the limiting plate is a high temperature resistant material.

9. The special welding method for sealing surface of high temperature and high pressure valve according to claim 1 is characterized in that: The material of the outer surface of the heat-insulating cover is a heat-insulating material.

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