Method for preventing and treating strain aging cracks after repair welding of nickel-based high-temperature alloy thin-wall casting with high Al and Ti contents

Abstract

The invention relates to a method for preventing and treating strain aging cracks after repair welding of a nickel-based superalloy thin-wall casting with high Al and Ti content, belongs to the technical field of material heat treatment, and solves the problems that in the prior art, the qualified rate of the high-Al and Ti-content superalloy thin-wall casting is low, the tendency of the strain aging cracks after repair welding is large, and a method for eliminating and preventing the cracks at the repair welding position lacks universality. A method for preventing and treating strain aging cracks after repair welding of a nickel-based high-temperature alloy thin-wall casting with high Al and Ti contents comprises pre-welding treatment and post-welding heat treatment, and the temperature rising speed of the post-welding heat treatment is larger than or equal to 10 DEG C / min. The tendency of post-welding strain aging cracks of the nickel-based superalloy with high Al and Ti contents is reduced, and the percent of pass of castings is improved.

Description

Technical Field

[0001] The invention relates to the technical field of material heat treatment, and in particular to a method for preventing and controlling strain aging cracks of a nickel-based high-temperature alloy casting with high Al and Ti contents after repair welding. Background Art

[0002] Nickel-based high-temperature alloys are widely used in the aviation field due to their excellent high-temperature strength and oxidation resistance. With the rapid development of my country's aviation industry, the thrust-to-weight ratio of aircraft engines has gradually increased, the service environment of the required materials has become more severe, and the alloying ratio of the required materials has also been continuously increasing. For example, a large amount of precipitation strengthening elements such as Al and Ti have been added to nickel-based high-temperature alloys to enhance the performance of the alloy. At the same time, the new generation of aircraft engine components are developing in the direction of integration, thin-walling, cavity complexity, and precision, which makes the minimum wall thickness of nickel-based high-temperature alloy components usually less than 3mm, and the integrated complex castings will inevitably have defects such as looseness, pores, and cracks during the casting process. We have to use repair welding to repair the casting defects, and heat treatment after welding to precipitate the strengthening phase of the alloy to improve the mechanical properties of the weld.

[0003] However, in nickel-based superalloys with high Al and Ti contents, a crack extending along the grain boundary will occur near the fusion zone during the post-weld aging treatment, which is called strain-age cracking (SAC). This crack is more likely to occur when the wall thickness is thin. The generation of this crack is related to the local accumulation of stress. Nickel-based superalloys with high Al and Ti contents will precipitate γ′-Ni3 (Al, Ti) phase and other phases during the post-weld heat treatment, resulting in local volume shrinkage of the alloy, generating tensile stress, and increasing the hardness of the alloy and reducing the plasticity. If this tensile stress is superimposed on the existing post-weld residual stress in the alloy, it may cause the total stress to exceed the plastic limit of the material and thus lead to the formation of SAC.

[0004] Although a lot of research has been carried out on SAC of nickel-based high-temperature alloy welds with high Al and Ti contents, there are differences between regular and straight welds and defect repair welds. The prevention and control methods for SAC of nickel-based high-temperature alloy repair welds are not sufficient, and are only targeted at specific castings and specific processes, which are accidental and lack universality. Summary of the invention

[0005] In view of the above analysis, an embodiment of the present invention aims to provide a method for preventing and controlling strain aging cracks of nickel-based high-temperature alloy castings with high Al and Ti contents after repair welding, so as to solve at least one of the problems of low qualified rate of existing high-temperature alloy thin-walled castings with high Al and Ti contents, large tendency of strain aging after repair welding, and lack of universality of the method for eliminating cracks at the repair welding.

[0006] An embodiment of the present invention provides a method for preventing and controlling strain aging cracks of a thin-walled nickel-based high-temperature alloy casting with high Al and Ti contents after repair welding, comprising pre-welding treatment and post-welding heat treatment, wherein the heating rate of the post-welding heat treatment is ≥10°C / min.

[0007] Specifically, the pre-welding treatment process is: using an oven or a heat treatment furnace to preheat the casting at 150-600° C. for 10-40 minutes, followed by furnace cooling or air cooling.

[0008] Furthermore, the post-weld heat treatment also includes post-weld solid solution, heating to the alloy standard solid solution temperature ±10°C at a rate of 10-30°C / min, keeping the temperature for a certain period of time, and air cooling.

[0009] Specifically, the post-weld solution heat preservation time is 10 minutes to 5 hours.

[0010] Furthermore, the post-weld heat treatment also includes post-weld aging, after solid solution welding and air cooling to room temperature, the temperature is raised to the alloy standard aging temperature ±10°C, kept at this temperature for a certain period of time, and air cooled.

[0011] Exemplarily, the post-weld aging holding time is 10 minutes to 4 hours.

[0012] Optionally, the post-weld solution is cooled to the alloy standard aging temperature ±10° C. by air cooling or furnace cooling, kept at this temperature for 10 min to 4 h, and air cooled.

[0013] It is worth noting that, based on mass fraction, the method for preventing and controlling strain aging cracks after repair welding is applicable to nickel-based high-temperature alloys with γ' phase forming elements Al+Ti≥5%.

[0014] It should be noted that the method for preventing and controlling strain aging cracks after repair welding is applicable to thin-walled parts with a wall thickness of ≤3 mm at the repair welding location.

[0015] Specifically, the room temperature tensile strength of the repair weld is not less than 85% of the base material.

[0016] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0017] 1. The present invention designs a complete pre-welding and post-welding heat treatment process and related process parameters for nickel-based high-temperature alloys with high Al and Ti contents, ensuring that there are no cracks inside or outside the repair welds after post-welding heat treatment, greatly improving the qualified rate of high-temperature alloy castings.

[0018] 2. The full-process prevention and control method for strain aging cracks of nickel-based high-temperature alloy repair welding castings provided by the present invention is applicable to all nickel-based high-temperature alloys, and has no requirements on the composition, wall thickness, and size of the castings;

[0019] Especially for alloy parts with Al+Ti≥5% and wall thickness≤3mm, the pre-welding and post-welding heat treatment processes provided by the present invention can still achieve crack-free inside and outside of the repair welding points after post-welding heat treatment, thereby expanding the application scope of the repair welding method for repairing high-temperature alloy parts.

[0020] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can become obvious from the description, or can be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0022] Figure 1 This is an X-ray fluorescence spectrum of the soldering point of Example 1 of the present invention;

[0023] Figure 2 This is an X-ray fluorescence spectrum of the soldering point of Example 2 of the present invention;

[0024] Figure 3 This is an X-ray fluorescence spectrum of the soldering point of Comparative Example 1 of the present invention;

[0025] Figure 4 This is the X-ray fluorescence spectrum of the soldering point of comparative example 2 of the present invention. DETAILED DESCRIPTION

[0026] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0027] At present, the development trend of the design and manufacturing of aero-engine components is high alloying, lightweight, thin-walled, complex and precise. The material characteristics of high alloying make it inevitable that castings will have multiple (usually >10) loose, pores, cracks and other defects, which need to be repaired by repair welding. Compared with regular and straight welds, the welds have a short residence time per unit area, while the weld repair residence time is long, the heat input is larger, and the stress field is concentrated, which will produce greater residual stress. It is necessary to eliminate the residual stress through multi-stage post-weld heat treatment and control the structural stress that may be generated during the heat treatment process to avoid cracking. Al and Ti elements are the main precipitation strengthening elements. Adding high Al and Ti elements can significantly improve the high temperature performance of the alloy. At the same time, through precipitation strengthening and grain refinement mechanisms, the overall performance of the material is improved, but it also increases the stress concentration and thermal crack sensitivity during welding and heat treatment; thin-wall design further increases the risk of crack initiation. Thin-walled structures are more susceptible to thermal stress during welding, leading to the formation and expansion of cracks.

[0028] Based on the above background, the development of a full-process prevention and control method for strain aging cracks in nickel-based high-temperature alloy thin-walled castings during repair welding is of great significance for improving the qualification rate of high-temperature alloy castings, solving the welding performance shortcomings caused by high alloying of Al and Ti and thin-walled castings, and promoting the practical application of high-performance nickel-based high-temperature alloys.

[0029] A specific embodiment of the present invention discloses a method for preventing and controlling strain aging cracks of a thin-walled nickel-based high-temperature alloy casting with high Al and Ti content after repair welding, comprising pre-welding treatment and post-welding heat treatment, wherein the heating rate of the post-welding heat treatment is ≥10°C / min.

[0030] Preferably, the pre-welding treatment process is: using an oven or a heat treatment furnace to preheat the casting at 150-600° C. for 10-40 minutes, followed by furnace cooling or air cooling.

[0031] By preheating before welding, the temperature difference during welding can be reduced, thereby reducing the thermal stress generated during the welding process and further reducing the residual stress after welding.

[0032] Furthermore, the post-weld heat treatment also includes post-weld solid solution, heating to the alloy standard solid solution temperature ±10°C at a rate of 10-30°C / min, keeping the temperature for a certain period of time, and air cooling.

[0033] The post-weld solution heat preservation time is 15 minutes to 5 hours.

[0034] First, the material is softened by rapid heating, and local plastic deformation is generated to release residual stress, preventing the occurrence of strain aging cracks caused by excessive local stress during subsequent processing; by rapidly heating over the γ′ phase precipitation temperature range, the welding residual stress that cannot be released during the heating process, the aging stress caused by the precipitation of the strengthening phase, and the thermal stress caused by uneven thermal expansion are effectively reduced, thereby effectively avoiding intergranular cracking caused by the superposition of the three. After welding, a part of the γ+γ′ eutectic phase and γ′ phase in the alloy is dissolved back by solid solution, and the precipitation amount of the eutectic phase and γ′ phase when they precipitate again is reduced, so as to improve plasticity, reduce organizational stress, and reduce crack sources; at the same time, the elements in the alloy are fully diffused, the chemical composition segregation of the alloy is reduced, and carbides will not precipitate in large quantities, thereby reducing the sensitivity of cracks.

[0035] In one possible design, the standard solution temperature is 1190°C, and the post-weld solution treatment is heated to 1190°C at a heating rate of 20°C / min, kept at this temperature for 0.5h, and then air-cooled.

[0036] Furthermore, the post-weld heat treatment also includes post-weld aging, heating to the alloy standard aging temperature ±10°C, keeping the temperature for a certain period of time, and air cooling.

[0037] The post-weld aging holding time is 15 minutes to 4 hours. If the holding time is too long, a large amount of carbides and other phases will be precipitated at the grain boundaries, which will reduce the plasticity, weaken the grain boundary strength, and easily crack due to stress.

[0038] In one possible design, the base material is K423A alloy, the standard aging temperature is 1060°C, and the post-weld aging treatment is heating to 1060°C, keeping warm for 0.5h, and air cooling.

[0039] Optionally, the post-weld solution is cooled to the alloy standard aging temperature ±10°C by air cooling or furnace cooling, kept at this temperature for 10min to 4h, and air cooled;

[0040] After solid solution air cooling to the standard aging temperature ±10℃ after welding, aging treatment is carried out. Compared with air cooling to room temperature and then heating to the aging temperature, although the mechanical properties of the repair weld are slightly worse, it can still meet the requirements for component use and save post-weld heat treatment time.

[0041] Specifically, the aging crack prevention method of the present invention is applicable to nickel-based high-temperature alloys with γ' phase forming elements Al+Ti≥5% by mass fraction.

[0042] For alloy parts with Al+Ti≥5% and wall thickness of the repair weld ≤3mm, through the existing aging heat treatment process, the casting precipitates γ' phase and other phases during the post-weld aging process, causing the matrix to shrink and generate tensile stress. After superposition with the local residual stress, it is easy to exceed the tensile limit of the thin wall, resulting in cracking of the thin wall. It is necessary to eliminate the residual stress and control the structural stress that may be generated during the heat treatment process through multi-stage post-weld heat treatment to avoid cracking. The present invention first effectively reduces the residual stress after welding through preheating before welding, and then dissolves most of the strengthening phases through the solid solution process, reduces the structural stress and reduces the crack source. In this way, after the γ' strengthening phase is precipitated again after the post-weld aging, the mechanical properties of the weld can be improved and the generation of strain aging cracks can be avoided.

[0043] Specifically, the room temperature tensile strength of the repair weld is not less than 85% of the base material.

[0044] It should be noted that if there are specific requirements for the alloy post-weld heat treatment process, after pre-weld treatment and repair welding, the heating rate for special post-weld heat treatment must not be lower than 10℃ / min.

[0045] For example, a K423A alloy transition section casting requires a post-weld heat treatment process of 1060℃ / 0.5h+3-4℃ / min cooling to 1000℃+air cooling to room temperature. The heating rate from room temperature to 1060℃ must not be less than 10℃ / min.

[0046] In summary, the present invention designs a complete pre-welding and post-welding heat treatment process and related process parameters for high Al and Ti content nickel-based high-temperature alloy thin-walled castings, ensuring that there are no cracks inside and outside the repair welds after post-welding heat treatment, greatly improving the qualified rate of high-temperature alloy castings, and has a wide range of applications without requirements on casting composition, wall thickness, and size.

[0047] The method for preventing and controlling strain aging cracks of nickel-based high-temperature alloy castings with high Al and Ti contents after repair welding of the present invention is described below in conjunction with specific embodiments.

[0048] Example 1

[0049] This embodiment provides a method for preventing and controlling strain aging cracks of nickel-based high-temperature alloy castings after repair welding.

[0050] The base material is K423A alloy, the standard solution temperature is 1190℃, and the standard aging temperature is 1060℃; the minimum wall thickness of the casting is 2mm, and 20 defects with a size ranging from Φ1-5mm are repaired by welding.

[0051] The specific process is:

[0052] 1. Preheating process before welding: Heat the casting to 150℃ in an oven and keep it warm for 20 minutes.

[0053] 2. Repair welding on defective parts of castings.

[0054] 3. Post-weld heat treatment:

[0055] 1. Solution treatment: heat to 1190℃ at a heating rate of 20℃ / min, keep warm for 0.5h, and air cool to room temperature;

[0056] 2. Aging treatment: heat to 1060℃ at a heating rate of 10℃ / min, keep warm for 0.5h, and air cool.

[0057] After the above process, no cracks were found inside all 20 welds, and the repair success rate was 100%; Figure 1 As shown, the results of fluorescence and X-ray testing show that there are no defects. The room temperature tensile strength of the base material is about 1052MPa, and the tensile strength of the repaired weld is about 966MPa. The tensile strength of the repaired weld is 91.8% of the tensile strength of the base material, which meets the requirement of 85% higher than the tensile strength of the base material.

[0058] Example 2

[0059] This embodiment provides a method for preventing and controlling strain aging cracks of nickel-based high-temperature alloy castings after repair welding.

[0060] The base material is K439B alloy, the standard solution temperature is 1160℃, and the standard aging temperature is 800℃; the wall thickness of the casting is 3mm, and 12 defects with a size ranging from Φ1-5mm are repaired by welding.

[0061] 1. Preheating process before welding: Heat the casting to 200℃ in an oven and keep it warm for 20 minutes.

[0062] 2. Repair welding on defective parts of castings.

[0063] 3. Post-weld heat treatment: Due to the requirements of component process specifications, post-weld heat treatment only performs solid solution treatment;

[0064] Solution treatment: heat up to 1160℃ at a heating rate of 10℃ / min, keep warm for 4h, and air cool.

[0065] No cracks were found inside the 11 solder joints after heat treatment. Figure 2 As shown, the fluorescence and X-ray test results of the crack-free weld area showed no defects; there was a slight crack in one weld area, and the repair success rate was 92%, and the casting could be used. The room temperature tensile strength of the base material was about 1190MPa, and the repaired weld was about 1226MPa, which was 85% higher than the base material tensile strength.

[0066] Example 3

[0067] This embodiment provides a method for preventing and controlling strain aging cracks of nickel-based high-temperature alloy castings after repair welding.

[0068] The base material is K423A alloy, the standard solution temperature is 1190℃, and the standard aging temperature is 1060℃; the minimum wall thickness of the casting is 2mm, and 20 defects with a size ranging from Φ1-5mm are repaired by welding.

[0069] The specific process is:

[0070] 1. Preheating process before welding: Heat the casting to 150℃ in an oven and keep it warm for 20 minutes.

[0071] 2. Repair welding on defective parts of castings.

[0072] 3. Post-weld heat treatment:

[0073] 1. Solution treatment: heat to 1190℃ at a heating rate of 20℃ / min, keep warm for 0.5h, and air cool to 1060℃;

[0074] 2. Aging treatment, keep warm for 0.5h, air cooling.

[0075] After the above process, no cracks were found inside all 20 welds, and the repair success rate was 100%. The results of fluorescence and X-ray testing showed no defects. The room temperature tensile strength of the base material was about 1052MPa, and the tensile strength of the repaired weld was about 908MPa. The tensile strength of the repaired weld was 86% of the tensile strength of the base material, which was higher than 85% of the tensile strength of the base material.

[0076] Comparative Example 1

[0077] This embodiment provides a method for preventing and controlling strain aging cracks of nickel-based high-temperature alloy castings after repair welding.

[0078] The base material is K423A alloy, the standard solution temperature is 1190℃, and the standard aging temperature is 1060℃; the minimum wall thickness of the casting is 2mm, and 18 defects with a size ranging from Φ1-5mm are repaired by welding.

[0079] The specific process is:

[0080] 1. No preheating treatment before welding.

[0081] 2. Repair welding on defective parts of castings.

[0082] 3. Post-weld heat treatment: Only aging treatment, heating to 1060℃ at a heating rate of 7℃ / min, keeping warm for 0.5h, and air cooling.

[0083] After the above process, no cracks were found inside 2 solder joints, but cracks appeared in 16 solder joints, and the repair success rate was only 11%, so the parts were scrapped. Figure 3 shown.

[0084] Comparative Example 2

[0085] This embodiment provides a method for preventing and controlling strain aging cracks of nickel-based high-temperature alloy castings after repair welding.

[0086] The base material is K423A alloy, the standard solution temperature is 1190℃, and the standard aging temperature is 1060℃; the minimum wall thickness of the casting is 2mm, and 20 defects with a size ranging from Φ1-5mm are repaired by welding.

[0087] The specific process is:

[0088] 1. No preheating treatment before welding.

[0089] 2. Repair welding on defective parts of castings.

[0090] 3. Post-weld heat treatment:

[0091] 1. Solution treatment, 730℃ / 4h, heating rate 10℃ / min, furnace cooling.

[0092] 2. Aging treatment, 1060℃ / 0.5h, air cooling, heating rate 10℃ / min.

[0093] After the above process, no cracks were found inside 5 solder joints, but cracks appeared in 15 solder joints. The repair success rate was only 25%, and the parts were scrapped. Figure 4 shown.

[0094] Comparative Example 3

[0095] This embodiment provides a method for preventing and controlling strain aging cracks of nickel-based high-temperature alloy castings after repair welding.

[0096] The base material is K423A alloy, the standard solution temperature is 1190℃, and the standard aging temperature is 1060℃; the minimum wall thickness of the casting is 2mm, and 13 defects with a size ranging from Φ1-5mm were repaired by welding.

[0097] The specific process is:

[0098] 1. Preheating process before welding: Heat the casting to 150℃ in a heat treatment furnace and keep it warm for 20 minutes.

[0099] 2. Repair welding on defective parts of castings.

[0100] 3. Post-weld heat treatment:

[0101] 1. Solution treatment: heat to 1190℃ at a heating rate of 5℃ / min, keep warm for 0.5h, and air cool;

[0102] 2. Aging treatment: heat to 1060℃ at a heating rate of 10℃ / min, keep warm for 0.5h, and air cool.

[0103] After the above process, no cracks were found inside 9 welds, cracks occurred in 4 weld areas, and the repair success rate was 70%.

[0104] Comparative Example 4

[0105] This embodiment provides a method for preventing and controlling strain aging cracks of nickel-based high-temperature alloy castings after repair welding.

[0106] The base material is K423A alloy, the standard solution temperature is 1190℃, and the standard aging temperature is 1060℃; the minimum wall thickness of the casting is 2mm, and 21 defects with a size ranging from Φ1-5mm were repaired by welding.

[0107] The specific process is:

[0108] 1. No preheating process before welding.

[0109] 2. Repair welding on defective parts of castings.

[0110] 3. Post-weld heat treatment:

[0111] 1. Solution treatment: heat to 1190℃ at a heating rate of 5℃ / min, keep warm for 0.5h, and air cool;

[0112] 2. Aging treatment: heat to 1060℃ at a heating rate of 10℃ / min, keep warm for 0.5h, and air cool.

[0113] After the above process, no cracks were found inside the 13 welds, cracks occurred in 8 weld areas, and the repair success rate was 61%.

[0114] Example 1 adopts the pre-welding and post-welding heat treatment processes of the complete nickel-based high-temperature alloy with high Al and Ti contents provided by the present invention, and the relevant process parameters meet the requirements of the present invention, the repair success rate of the repair welding is 100%, and there are no defects after fluorescence and X-ray detection results, and the tensile strength of the repair welding meets the requirement of 85% higher than the tensile strength of the base material; Compared with Example 1, Comparative Example 1 does not perform preheating before welding, and only performs aging treatment during the post-welding heat treatment, and the heating rate of the aging process is low, which does not meet the requirements of the present invention, resulting in the failure of defect repair and the scrapping of parts; Compared with Example 1, Comparative Example 2 does not perform preheating before welding, and the solution temperature of the post-welding heat treatment is lower than the standard solution temperature, resulting in the failure of defect repair and the scrapping of parts; Compared with Example 1, Comparative Example 3 has a lower heating rate of post-welding solution treatment, resulting in a low success rate of defect repair, and the casting cannot be guaranteed to be qualified; Compared with Example 1, Comparative Example 4 lacks preheating before welding and has a lower heating rate of solution treatment, resulting in a further reduction in the success rate of defect repair, and the casting cannot be guaranteed to be qualified.

[0115] Example 2 Due to the strict requirements of the component process specifications, only solution treatment is performed, and the relevant process parameters meet the requirements of the present invention. Although the defect repair success rate is less than 100%, the casting can be used.

[0116] Example 3 adopts the scheme of post-weld heat treatment by cooling the alloy to the standard aging temperature at the speed of air cooling after welding, which saves time. Although the tensile strength of the repair weld is not as good as that of Example 1, it can still meet the requirement of not less than 85% of the tensile strength of the base material.

[0117] In summary, the present invention designs a complete pre-weld and post-weld heat treatment process and related process parameters for nickel-based high-temperature alloys with high Al and Ti contents, ensuring that there are no cracks inside and outside the repair welds after post-weld heat treatment, greatly improving the qualified rate of high-temperature alloy castings, and has a wide range of applications without requirements for casting composition, wall thickness, and size.

[0118] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for preventing and controlling strain aging cracks of thin-walled nickel-based high-temperature alloy castings with high Al and Ti contents after repair welding, characterized in that: It includes pre-weld treatment and post-weld heat treatment, and the heating rate of the post-weld heat treatment is ≥10°C / min.

2. The control method according to claim 1, characterized in that: The pre-welding treatment process is: using an oven or a heat treatment furnace to preheat the casting at 150-550° C. for 10-40 minutes, followed by furnace cooling or air cooling.

3. The control method according to claim 1, characterized in that: The post-weld heat treatment also includes post-weld solid solution, heating at a rate of 10-30°C / min to the standard solid solution temperature of the alloy ±10°C, keeping the temperature for a certain period of time, and air cooling.

4. The control method according to claim 3, characterized in that: The post-welding solid solution holding time is 10 minutes to 5 hours.

5. The control method according to claim 4, characterized in that: The post-weld heat treatment also includes post-weld aging, after the post-weld solid solution is air-cooled to room temperature, the temperature is then raised to the alloy standard aging temperature ±10°C, kept at this temperature for a certain period of time, and air-cooled.

6. The control method according to claim 5, characterized in that: The post-weld aging insulation time is 10 minutes to 4 hours.

7. The control method according to claim 3, characterized in that: The post-weld solution is cooled to the alloy standard aging temperature ±10°C by air cooling or furnace cooling, kept at this temperature for 10min to 4h, and then air cooled.

8. The control method according to claim 1, characterized in that: Measured by mass fraction, the method for preventing and controlling strain aging cracks after repair welding is applicable to nickel-based high-temperature alloys with γ' phase forming elements Al+Ti≥5%.

9. The control method according to claim 1, characterized in that: The method for preventing and controlling strain aging cracks after repair welding is applicable to thin-walled parts with a wall thickness of ≤3 mm at the repair welding location.

10. The control method according to claim 9, characterized in that: The room temperature tensile strength of the repair weld shall not be less than 85% of the base material.

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