A method for repairing a wall surface crack of a flame tube

Abstract

The application provides a method for repairing cracks on the wall surface of a flame tube, comprising the following steps: marking a window boundary line on the wall surface of a repaired part, the window boundary line containing ablation and / or local intensive cracks; cutting the repaired part along the window boundary line to cut off the area defined by the window boundary line, thereby forming a window to be repaired on the repaired part; marking a patch boundary line on a patch source part, the patch boundary line corresponding to the window on the repaired part; cutting the patch source part along the patch boundary line to obtain a patch; and welding the patch at the window of the repaired part; wherein the repaired part is a flame tube returned to the factory for repair; the patch source part is an out-of-tolerance part of an inner wall and outer wall assembly or an inner wall and outer wall part of a newly manufactured flame tube, and the patch does not have an out-of-tolerance characteristic. In the case of regional intensive cracks or burns on the wall surface of the flame tube, the inner wall and outer wall of the flame tube are not replaced, thereby reducing repair cost and shortening the repair cycle.

Description

Technical Field

[0001] This invention relates to the field of repairing the flame tube of an aircraft generator, and more specifically to a method for repairing cracks in the wall of the flame tube. Background Technology

[0002] The combustor is a critical component of an aero-engine, located inside the combustion chamber unit. It is the primary site of combustion, operating at temperatures as high as 1400K, making it the component subjected to the highest temperature load in the engine. Its main function is to mix fuel and compressed air from the compressor for combustion, converting the chemical energy of the fuel into heat energy to heat the high-pressure air compressed by the compressor, which then expands and performs work in the turbine and exhaust system. The combustor is made of high-temperature alloy materials; however, due to its long-term operation in a high-temperature, high-pressure, and high-load environment, stress-induced cracks can appear on its walls after a certain period of use, posing a significant safety hazard to the engine. Therefore, aero-engines require periodic maintenance after a certain service life cycle. Because of the combustor's complex structure, long manufacturing cycle, and high value, replacing it with a new part would significantly increase engine costs, resulting in substantial economic losses, and would also severely extend the engine's repair cycle. Summary of the Invention

[0003] The purpose of this invention is to provide a repair method for flame tube wall cracks that appear in areas of dense cracks or burns after an aircraft engine is returned to the factory. This method does not require replacing the inner and outer walls of the flame tube, thus reducing repair costs and shortening the repair cycle.

[0004] This invention is achieved through the following technical solution:

[0005] A method for repairing cracks in the wall of a flame tube includes:

[0006] Draw lines on the wall of the repair part to mark the window boundary lines containing ablation and / or localized dense cracks;

[0007] Cut along the window boundary line on the repair part to remove the area defined by the window boundary line, thus forming the window to be repaired on the repair part;

[0008] Draw lines on the source part of the patch to mark the patch boundary line corresponding to the window described on the repair part;

[0009] The patch is obtained by cutting along the boundary line of the patch source part;

[0010] The patch is welded to the window of the repair part;

[0011] The repair part is a flame tube returned to the factory for repair; the patch source part is a newly manufactured flame tube inner and outer wall assembly or an out-of-tolerance part of the flame tube inner and outer wall components, and the patch does not have out-of-tolerance characteristics.

[0012] Preferably, both the window and the patch are rectangular in shape.

[0013] Preferably, the distance between the circumferential boundary line of the window and the end of the upper air film tongue at the location of the window is not less than 2.5 mm, and the distance between the lower circumferential boundary line and the end of the lower air film tongue at the location of the window is greater than the total length of the lower air film groove transverse wall and the lower air film tongue.

[0014] Preferably, the window boundary line satisfies the following conditions: when the window boundary line is located in the second and / or third air film section, the lower circumferential boundary line of the window boundary line is at least 9.1 mm away from the end of the lower air film tongue at the location of the window, and the axial boundary line is at least 5.8 mm away from the edge of the main combustion hole; when the window boundary line is located in the fourth and / or fifth air film section, the lower circumferential boundary line of the window boundary line is at least 7.6 mm away from the end of the lower air film tongue at the location of the window, and the axial boundary line is at least 5.8 mm away from the edge of the mixing hole.

[0015] Preferably, the patch is welded to the window of the repair part, specifically including:

[0016] S1, perform clamp repair on the window and patch to be repaired;

[0017] S2, insert the patch into the window of the repair part to be repaired;

[0018] S3, perform symmetrical positioning welding along the butt joint gap between the patch and the repair part's window;

[0019] S4. Adjust the shape of the patch to ensure that the mating gap between the patch and the window of the repair part is within 0.15mm and the misalignment between the patch and the wall substrate of the repair part is within 0.2mm.

[0020] S5, on the flame side of the repair part, bevel the joint between the patch and the window;

[0021] S6. Sand the weld seam around the patch and within 20mm of its two sides, and clean it with degreasing cotton soaked in acetone.

[0022] S7, perform argon arc welding on the weld between the window of the repair part and the surrounding area of ​​the patch;

[0023] S8, perform clamp repair on the argon arc weld around the patch.

[0024] Furthermore, when the crack in the repaired part extends to the bottom of the air film groove below the air film tongue, or when the axial weld of the patch needs to cross the air film tongue, or when there is a blockage in the air film hole, after S4 and before S5, it also includes: machining a U-shaped clearance groove at the position directly opposite the crack at the bottom of the air film groove on the air film tongue, or at the position corresponding to the axial weld of the patch, or at the position corresponding to the blockage in the air film hole.

[0025] Furthermore, prior to S1, the process also includes: grinding through cracks in the uncut area of ​​the repair part in a Y-shape, sanding and cleaning the ground area, repairing the sanded area with argon arc welding after cleaning, and then repairing the argon arc welded area with clamps.

[0026] Furthermore, prior to S1, the process also includes: grinding the ablation outside the window boundary line on the repair part in a concave shape, sanding and cleaning the ground area, repairing the sanded area with argon arc welding after cleaning, and then repairing the argon arc welded area with clamps.

[0027] Furthermore, prior to S1, the process also includes: grinding and peeling off the surface layer of shallow overheating marks or shallow dense cracks outside the window boundary line on the repair part, sanding and cleaning the ground area, repairing the sanded area with argon arc welding after cleaning, and then repairing the argon arc welded area with clamps.

[0028] Furthermore, prior to S1, the process also includes: grinding and creating V-grooves in the non-penetrating cracks in the uncut area of ​​the repair part, sanding and cleaning the ground area, repairing the sanded area with argon arc welding after cleaning, and then repairing the argon arc welded area with clamps.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] This invention addresses the issue that during the manufacturing of new flame tube inner and outer wall components, the complexity of these components inevitably leads to out-of-tolerance parts due to dimensional deviations. While these out-of-tolerance parts cannot be directly assembled onto the engine, their other characteristics conform to the dimensional requirements of the flame tube drawings. Scrapping these parts directly would result in significant economic losses. This invention, after fully considering the structure and usage of the flame tube components, utilizes out-of-tolerance parts generated during the new product stage, provided their deviations are under control, as source parts (donors) for patching. Based on the wall damage of overhauled return parts (recipients) after use, a specific sized cutting area is marked at the damaged location, and the damage is completely or partially removed. Then, a patch of the same size is cut from the same location on the source part and welded to the damaged area of ​​the return part using argon arc welding. This solves the problem of repairing returned flame tube parts and also achieves the rational utilization of out-of-tolerance parts, saving substantial funds and reducing scrap losses.

[0031] Furthermore, the advantage of forming both the window and the supplementary segment into rectangles is that the process is simple, easy to cut and repair, and easier to mark the cutting lines for features such as the gas film tongue, main combustion hole, and mixing hole on the parts.

[0032] Furthermore, the size requirements of the window boundary line designed in this invention can ensure that the upper and lower cutting lines of the window and patch avoid the upper gas film tongue and the lower gas film groove transverse wall, and that the axial cutting lines avoid the main combustion hole and mixing hole, which can effectively meet the functional requirements of the main combustion hole and mixing hole in the flame tube.

[0033] Furthermore, this invention provides specific methods for fitting and welding the patch and the window. The small gap fit and misalignment between the patch and the window of the repaired part ensure the consistency of the patch's position and the surface profile between the patch and the substrate, making the airflow in the flow channel smoother and minimizing airflow turbulence. Especially when the patch contains main combustion holes and mixing holes, the consistency of the main combustion holes and mixing holes after welding the patch can achieve stable combustion, stabilize engine performance, and reduce performance degradation.

[0034] Furthermore, when the crack extends to the bottom of the film gas groove below the film gas tongue, or when the axial weld of the patch needs to cross the double wall, or when there is a blockage in the film gas hole, a U-shaped clearance groove is machined on the film gas tongue to avoid the weld below the film gas tongue, which facilitates the subsequent repair of the crack extending to the bottom of the film gas groove, the welding of the patch, or the opening of the blocked film gas hole. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the inner wall structure of the flame tube;

[0036] Figure 2 A schematic diagram of the damage morphology of the inner wall surface of the flame tube;

[0037] Figure 3 This is a schematic diagram showing the cutting location of the window on the inner wall of the flame tube;

[0038] Figure 4 A schematic diagram of the damaged area outside the window on the inner wall of the flame tube;

[0039] Figure 5 A schematic diagram of the grinding structure for the damaged area outside the window on the inner wall of the flame tube;

[0040] Figure 6 A schematic diagram of argon arc welding in the damaged area outside the window;

[0041] Figure 7 This is a schematic diagram showing the structure and location of the U-shaped groove opening. Detailed Implementation

[0042] To further understand the present invention, the present invention will be described below with reference to embodiments. These descriptions are only for further explaining the features and advantages of the present invention and are not intended to limit the claims of the present invention.

[0043] Hereinafter, the flame tube returned to the factory for repair is referred to as the repair part (as the recipient), and the flame tube inner and outer wall components or inner and outer wall parts that are out of tolerance produced during the new product manufacturing process are referred to as the patch source part (as the donor). In a specific embodiment of the present invention, the flame tube refers to the flame tube of an aero-engine.

[0044] The method for repairing cracks in the flame tube wall of the present invention specifically includes the following steps:

[0045] (1) Shaping: For bulges on the wall of the repair part, after shimming the back with a pad, use a hammer to tap and shape the bulge area to restore it to its original shape as much as possible. There should be no obvious visual difference. It is strictly forbidden to tap and correct bulges while the part is suspended in the air without shimming, as this may cause unnecessary secondary deformation of the repair part. (2) Shaping the inner and outer walls of the flame tube... Figure 1 For the burned and deformed area, use a pry bar to insert into the air film groove for correction, so that the collapsed and deformed area of ​​the air film tongue can be restored to its original surface state as much as possible, and there should be no obvious difference visually.

[0046] (2) Marking: According to the specific location of ablation and localized dense cracks on the repaired part, follow the example shown. Figure 2 Draw lines on the repair part (recipient) to mark the location and boundary lines of the window to be excavated, which includes areas of ablation and / or localized dense cracks.

[0047] When drawing lines, try to make the shape of the window to be excavated a regular rectangle while ensuring the dimensions.

[0048] The circumferential boundary line of the window must be at least 2.5 mm from the edge of its upper air film tongue (the end of the upper air film tongue), and the circumferential boundary line of the lower air film tongue must be at least 2.5 mm from the end of its lower air film tongue. Figure 3 ).

[0049] When marking ablation or locally concentrated crack areas (circumferential cutting lines should not pass through the gas film tongue or its vertical wall), such as Figure 2 As shown, when the window boundary line is located in the second and / or third gas film section, its lower circumferential boundary line is at least 9.1 mm in front of the trailing edge (the end of the lower gas film tongue), and its axial boundary line is at least 5.8 mm away from the edge of the main combustion hole; when the window boundary line is located in the fourth and / or fifth gas film section, its lower circumferential boundary line is at least 7.6 mm in front of the trailing edge (the end of the lower gas film tongue), and its axial boundary line is at least 5.8 mm away from the edge of the mixing hole.

[0050] (3) Cutting the window to be excavated: Based on the window boundary line defined by the lines marked on the wall of the repair part ( Figure 2 ), excise the ablation and / or locally dense crack defects enclosed by the window boundary line, such as Figure 4 As shown.

[0051] (4) Grinding and cleaning: Grind the through cracks in the uncut area of ​​the repair part wall in a Y-shape. Figure 5 (a)); The ablation outside the boundary line (i.e., the ablation that cannot be included in the window to be excavated according to the above marking requirements) is ground in a concave shape. Figure 5 (b) The grinding depth is approximately 1 / 2 of the wall thickness of the repaired part or leaves a 0.5mm impermeable layer; shallow overheating marks or shallow dense cracks outside the boundary line are ground off by removing surface defects. Figure 5 (c) The grinding depth is approximately 1 / 2 the thickness of the inner wall of the repaired part. V-grooves are ground into non-penetrating cracks on the flame tube wall. Figure 5 (d) The groove depth is about 1 / 2 of the wall thickness of the repair part or leaves a bottom of 0.5mm to prevent penetration; use sandpaper to sand the grinding area outside the window cutting line (boundary line) to remove the surface oxide layer until a bright metallic luster is exposed, and clean the sanded area with degreasing cotton soaked in acetone.

[0052] (5) Argon arc welding: according to Figure 6 The area shown is repaired by argon arc welding, Class I weld.

[0053] When welding repairs involve the gas film groove / gas film tongue, a copper backing plate should be inserted into the gas film groove before welding to improve the forming quality of the back of the gas film tongue, and at the same time control the amount of deformation of the gas film tongue.

[0054] (6) Grinding: Grind all welded repair areas on the inner wall of the repaired part to make a smooth transition with the main body. The weld reinforcement should not exceed 0.3mm. For hard-to-reach areas on the flameless side, the weld repair area should be uniformly transitioned, and the weld reinforcement should not exceed 1mm (the thickness of the base material should not be reduced).

[0055] (7) Radiographic inspection: Radiographic inspection shall be carried out on all welded repair parts on the inner wall surface of the repaired parts in accordance with HB20160-2014, Class I welds.

[0056] (8) Fluorescence detection: Perform fluorescence detection on all welded repair parts on the inner wall surface of the repaired parts in accordance with HB / Z61-1998, and conduct acceptance in accordance with Q / S10-1238-2018 for Class I welds.

[0057] (9) Marking on the patch source part: Based on the number, actual position, and actual size of the windows cut out on the repair part (recipient), mark the patch source part (donor) with dimensions exactly the same as the part to be repaired, as shown in the example. Mark the position and boundary line of the patch to be prepared on the patch source part (donor). The position and size of the patch correspond to the position and size of the windows cut out on the repair part.

[0058] When marking lines, while ensuring dimensions, try to process the patch shape into a regular rectangular patch. If necessary, adjustments can be made according to the actual position and size of the window on the repair part to ensure the fitting quality.

[0059] When marking the patch to be prepared (the circumferential boundary line should not pass through the gas film tongue or the vertical wall of the gas film tongue), if the patch boundary line is located in the second and / or third gas film segment, its lower circumferential boundary line should be at least 9.1 mm in front of the trailing edge (the end of the lower gas film tongue), and its axial boundary line should be at least 5.8 mm away from the edge of the main combustion hole; if the patch boundary line is located in the fourth and / or fifth gas film segment, its lower circumferential boundary line should be at least 7.6 mm in front of the trailing edge (the end of the lower gas film tongue), and its axial boundary line should be at least 5.8 mm away from the edge of the mixing hole.

[0060] This step is only performed when the part (recipient) to be repaired has ablation or localized dense cracks that cannot be repaired by conventional processes and must be repaired by inlay welding patch process.

[0061] (10) Cutting and preparing the patch: The patch is prepared by cutting at the same location as the window of the patch source part (donor) and the repair part (recipient). That is, the patch is obtained by cutting along the patch boundary line on the patch source part.

[0062] The source parts (donors) of the patch should comply with quality procedures, and the source parts (donors) of the patch should be able to prove that there are no quality problems in the cut area.

[0063] The source component (donor) of the patch should meet the relevant life control requirements.

[0064] The patch size should be equal to or slightly larger than the window size to be repaired, to ensure adequate clamping allowance.

[0065] When cutting, try to maintain the integrity of the original markings on the source part of the patch. When it is necessary to pass through the marked location, the markings should be transferred according to the original marking method so that the remaining parts are traceable and manageable.

[0066] The patch source component (donor) includes, but is not limited to, the inner and outer wall components of the flame tube, and may also be other components such as the inner and outer walls from which the required patch can be cut. The patch portion on the patch source component does not exhibit any out-of-tolerance characteristics. The out-of-tolerance components and out-of-tolerance characteristics mentioned above are conventional technical terms in the art and will be understood by those skilled in the art.

[0067] The four corners of the window and patch are machined with radius R, ideally R3±1. This reduces welding stress at the corners of the patch and ensures tool strength during corner machining. The radius R is a process requirement; the R value is not a specific, mandatory acceptance requirement, but rather depends on the actual fit between the patch and the window.

[0068] This step is performed only when necessary, and only when the wall surface of the part to be repaired has ablation / localized dense crack defects that require repair using a patch welding process.

[0069] (11) Repairing windows and patches: Repair the windows of the parts to be fitted with patches, remove the spatter and burrs around them, and repair the remelted layer on the window section to expose a bright metallic luster. At the same time, the windows to be fitted with patches should be as regular as possible after repair.

[0070] According to the shape and size of the window to be filled on the repair part (recipient), the patch to be welded is repaired by clamping, removing the remelted layer and burrs around the patch to expose a bright metallic luster, while ensuring that the gap between the patch and the window to be filled on the repair part is within 0.15mm.

[0071] (12) Assembly: Fill the patch to be welded into the window of the patch to be welded on the wall of the repair part, adjust the position of the patch so that the gap between the window and the patch to be welded along the surrounding surface is within 0.15mm, and the misalignment between the patch and the inner wall substrate of the repair part is within 0.2mm.

[0072] (13) Tack welding: Along the weld between the patch and the window to be repaired on the wall of the repair part, 4-8 symmetrical tack welds are made, Class I welds.

[0073] (14) Correction: Ensure that the gap between the patch to be welded and the window to be repaired on the wall of the repair part is within 0.15mm, and the misalignment between the patch to be welded and the base of the repair part (including the misalignment in the wall thickness direction and the axial misalignment, the axial misalignment can be obtained by checking the misalignment of the end of the air film tongue between the patch and the adjacent base, or by checking the misalignment of the shoulder where the air film hole is located between the patch and the adjacent base) is within 0.2mm.

[0074] (15) U-shaped clearance groove: When the crack extends to the bottom of the gas film groove below the gas film tongue in the double-wall area, or when the axial weld of the patch to be welded needs to cross the double wall (corresponding area of ​​the gas film tongue), or when there is a blockage in the gas film hole, a U-shaped clearance groove is machined as shown in the figure at the position directly opposite the crack at the bottom of the gas film groove on the gas film tongue, or at the position corresponding to the axial weld of the patch to be welded, or at the position corresponding to the blocked gas film hole. Figure 7 (Avoid the weld seam below the film gas tongue) so that subsequent repairs can be made to cracks extending to the bottom of the film gas groove, longitudinal welds can be applied to the patch, or blocked film gas holes can be cleared.

[0075] (16) Beveling: On the flame side, beveling the area between the patch and the window to be repaired on the wall around the patch to be welded, ensuring that the beveling depth is about 1 / 2 of the wall thickness of the repaired part, or leaving a 0.5mm bottom without penetration.

[0076] (17) Sanding and cleaning: Sand the weld seam around the patch and within 20mm of its two sides with sandpaper, and clean it with degreased cotton soaked in acetone.

[0077] (18) Argon arc welding: Argon arc welding is performed on the weld seams of the repair part wall window and around the patch, Class I weld seams.

[0078] Argon gas protection should be used during welding. A welding support can be used for argon gas protection; for parts with significant structural limitations, a custom-made welding support can also be used.

[0079] When welding the gas film tongue, a copper backing plate should be placed in the gas film groove to improve the forming quality of the back of the gas film tongue, and at the same time, it can also control the amount of deformation of the gas film tongue.

[0080] If the air film pores are blocked, electrical discharge drilling should be performed beforehand without sealing the air film tongue.

[0081] (19) Visual inspection: Visually inspect the argon arc weld around the patch at the repair part wall surface, Class I weld.

[0082] Inspect the film vents at the welded patch area; no blockages are allowed. If any blockages are found, mark the specific location, number, and diameter of the blockage on the physical object and record the details for future hole clearing.

[0083] (20) When the patch is installed on the wall of the repaired part, the argon arc weld around the patch is smoothly connected to the main body, the weld height shall not exceed 0.3mm, and it is not allowed to be recessed into the base of the repaired part.

[0084] For hard-to-reach areas on the flameless side, the repair area should be welded evenly, and the weld reinforcement should not exceed 1mm (regardless of whether it is the flameless side or the flameless side, the thickness of the base material should not be reduced).

[0085] For welds extending into the film cooling tank, the weld should be clamped to make it flush with the tank, and no weld beads are allowed at the bottom radius (R). The inlet or mixing hole should also be clamped. The outlet height of the film cooling tank near the weld should be checked and corrected to be no less than 1.7 mm. This step is not necessary if the film cooling tank is functioning properly, has not been repaired, or the weld is far from the tank.

[0086] (21) Radiographic inspection: Radiographic inspection shall be carried out on the argon arc weld around the patch at the patch on the wall of the repair part in accordance with HB20160-2014, and the acceptance shall be carried out in accordance with Q / S10-1238-2018, Class I weld.

[0087] (22) Fluorescence detection: Perform fluorescence detection on the argon arc weld around the patch at the wall of the repair part according to HB / Z61-1998, Class I weld.

[0088] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for repairing cracks in the wall of a flame tube, characterized in that, include: Draw lines on the wall of the repair part to mark the window boundary lines containing ablation and / or localized dense cracks; the window boundary lines meet the following requirements: the circumferential boundary line of the window boundary line is not less than 2.5 mm from the end of the upper gas film tongue at the location of the window, and the distance of the lower circumferential boundary line of the window boundary line from the end of the lower gas film tongue at the location of the window is greater than the total length of the lower gas film groove transverse wall and the lower gas film tongue; when the window boundary line is located in the second and / or third gas film segment, the distance of the lower circumferential boundary line of the window boundary line from the end of the lower gas film tongue at the location of the window is at least 9.1 mm, and the axial boundary line is at least 5.8 mm from the edge of the main combustion hole; when the window boundary line is located in the fourth and / or fifth gas film segment, the distance of the lower circumferential boundary line of the window boundary line from the end of the lower gas film tongue at the location of the window is at least 7.6 mm, and the axial boundary line is at least 5.8 mm from the edge of the mixing hole; Cut along the window boundary line on the repair part to remove the area defined by the window boundary line, thus forming the window to be repaired on the repair part; Draw lines on the source part of the patch to mark the patch boundary line corresponding to the window described on the repair part; The patch is obtained by cutting along the boundary line of the patch source part; The patch is welded to the window of the repair part, specifically including: S1, perform clamp repair on the window and patch to be repaired; S2, insert the patch into the window of the repair part to be repaired; S3, perform symmetrical positioning welding along the butt joint gap between the patch and the repair part's window; S4. Adjust the shape of the patch to ensure that the mating gap between the patch and the window of the repair part is within 0.15mm and the misalignment between the patch and the wall substrate of the repair part is within 0.2mm. S5, on the flame side of the repair part, bevel the joint between the patch and the window; S6. Sand the weld seam around the patch and within 20mm of its two sides, and clean it with degreasing cotton soaked in acetone. S7, perform argon arc welding on the weld between the window of the repair part and the surrounding area of ​​the patch; S8, perform clamp repair on the argon arc weld around the patch; When the crack in the repaired part extends to the bottom of the air film groove below the air film tongue, or when the axial weld of the patch needs to cross the air film tongue, or when there is a blockage in the air film hole, after S4 and before S5, it also includes: machining a U-shaped clearance groove at the position directly opposite the crack at the bottom of the air film groove on the air film tongue, or at the position corresponding to the axial weld of the patch, or at the position corresponding to the air film hole with a blockage. The repair part is a flame tube returned to the factory for repair; the patch source part is a newly manufactured flame tube inner and outer wall assembly or an out-of-tolerance part of the flame tube inner and outer wall components, and the patch does not have out-of-tolerance characteristics.

2. The method for repairing cracks in the flame tube wall according to claim 1, characterized in that, Both the window and the patch are rectangular in shape.

3. The method for repairing cracks in the flame tube wall according to claim 1, characterized in that, Before S1, it also includes: grinding through cracks in the uncut area of ​​the repair part in a Y-shape, sanding and cleaning the ground area, repairing the sanded area with argon arc welding after cleaning, and then repairing the argon arc welded area with clamps.

4. The method for repairing cracks in the flame tube wall according to claim 1, characterized in that, Before S1, it also includes: grinding the burn-out area outside the window boundary line on the repair part in a concave shape, sanding and cleaning the sanded area, repairing the sanded area with argon arc welding after cleaning, and then repairing the argon arc welded area with clamps.

5. The method for repairing cracks in the flame tube wall according to claim 1, characterized in that, Before S1, it also includes: grinding and peeling off the surface layer of shallow overheating marks or shallow dense cracks outside the window boundary line on the repair part, sanding and cleaning the grinding area, repairing the sanded area with argon arc welding after cleaning, and then repairing the argon arc welded area with clamps.

6. The method for repairing cracks in the flame tube wall according to claim 1, characterized in that, Before S1, it also includes: grinding and opening V-grooves in the non-penetrating cracks in the uncut area of ​​the repair part, sanding and cleaning the ground area, repairing the sanded area with argon arc welding after cleaning, and then repairing the argon arc welded area with clamps.

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