CN115354133B - Method for preventing local recrystallization of monocrystalline superalloy blade - Google Patents

Abstract

The invention discloses a method for preventing local recrystallization of a monocrystalline superalloy blade, which comprises the following steps in sequence: placing the monocrystal superalloy blade into a vacuum heat treatment furnace for recovery treatment; taking out the single-crystal superalloy blade from the vacuum heat treatment furnace, and directly mechanically polishing and grinding part of the blade; cleaning the mechanically polished single-crystal superalloy blade, and removing mechanically polished traces by adopting a local electrolytic machining or chemical corrosion mode; and carrying out solid solution aging treatment on the single-crystal superalloy blade. According to the technical scheme, the problem that the single-crystal superalloy blade is recrystallized in the subsequent solution heat treatment process due to the fact that large casting residual stress locally exists in the casting process due to the fact that the blade structure is complex can be effectively prevented.

Description

A method to prevent local recrystallization of single crystal high temperature alloy blades

Technical field

The invention belongs to the technical field of manufacturing aeroengine turbine blades, and specifically relates to a method for preventing local recrystallization of single crystal high-temperature alloy blades.

Background technique

Turbine blades are one of the most critical parts in turbine engines. They work in harsh environments and are subject to high temperatures and high stress. Single-crystal superalloys eliminate almost all grain boundaries and have good high-temperature comprehensive properties. They are considered key materials for manufacturing advanced aerospace engines and ground gas turbine turbine blades.

For single crystal superalloys, in order to obtain good mechanical properties, complete heat treatment is usually used, but the solution treatment temperature is high and the recrystallization tendency is large. On the one hand, compared with the grain boundaries produced during the casting solidification process, the strength of recrystallized grain boundaries is significantly lower; on the other hand, recrystallization produces transverse grain boundaries, forming a weak link in the blade and seriously affecting the performance of the blade. Therefore, single crystal superalloys and oriented columnar crystal blades must avoid recrystallization as much as possible.

During the directional solidification process of the blade, due to the complex shape of the blade, there is excessive casting residual stress concentration in the shrinkage area during the solidification and cooling process. After the directional solidification is completed, the large casting residual stress will cause subsequent solution heat treatment. Recrystallization defects are prone to occur.

The formation of recrystallization is because the casting stress or external stress during the blade preparation process produces a certain plastic deformation in the blade and stores a certain amount of strain energy. During the subsequent high-temperature heat treatment process, the strain energy is released in the form of recrystallization. Plastic deformation caused by casting stress due to solidification shrinkage during the casting process. If the density is high, it will cause recrystallization during the heat treatment process. This kind of recrystallization is usually relatively fixed in position and has strong repeatability, large size, and small quantity. feature. Under normal circumstances, if this kind of recrystallization occurs on the blade surface, the entire blade will be scrapped, which is also an important factor restricting the blade qualification rate. Therefore, there is an urgent need to develop a method to prevent local recrystallization of single crystal superalloy blades to reduce the risk of recrystallization in the blades and thereby improve the blade manufacturing qualification rate.

The invention patent application publication number CN107557869A discloses a method to avoid recrystallization of the platinum wire core support position of single crystal high-temperature alloy turbine blades. The blade core support position is polished with a hand-held grinder + felt wheel low-stress polishing + chemical corrosion surface treatment + The sequential method of step recovery heat treatment reduces the plastic strain layer and residual stress at the blade core support position; the corrosive liquid for chemical corrosion is hydrogen peroxide and hydrochloric acid, and the volume ratio of the corrosive liquid is H ₂ O ₂ :HCl=1: 8-10; the step recovery heat treatment is: (700-850℃)/(2-4h)+(1200-1230℃)/(0.5-1h)+(1250-1270℃)/(0.5-1h)+( 1200-1230℃)/(0.5-1h)+(1280-1300℃)/(0.5-1h)+(1250-1270℃)/(0.5-1h)+(1280-1300℃)/(0.5-1h) , the heating rate in all heating stages is ≤10℃/min. After the heat preservation time is reached, use furnace cooling to below 200℃ and release. This technical solution is a method to avoid recrystallization designed for the position of the platinum wire core support of single crystal high-temperature alloy turbine blades. Its operation sequence, process parameters, etc. are only suitable for avoiding recrystallization at the position of the platinum wire core support of the blade and are not applicable to the blade body. ; In addition, mechanical polishing and chemical corrosion are performed first, followed by recovery heat treatment. This sequence of operations is not conducive to promoting recrystallization nucleation, so recrystallization will still occur during subsequent solid solution aging treatment.

Contents of the invention

During the directional solidification process of single crystal superalloy blades, due to the complex shape of the blades, there is excessive casting residual stress concentration in the shrinkage area during the solidification and cooling process. After the directional solidification is completed, large casting residual stresses can easily lead to Recrystallization defects occur during subsequent solution heat treatment. The purpose of the present invention is to prevent single-crystal high-temperature alloy blades from recrystallizing during the subsequent solution heat treatment process due to the large local casting residual stress during the casting process due to the complex structure of the blade.

In order to achieve the above objectives, the present invention provides a method for preventing partial recrystallization of single crystal high-temperature alloy blades, which includes the following steps in sequence:

Step 1: Place the single crystal high-temperature alloy blade in a vacuum heat treatment furnace for recovery treatment;

Step 2: Take out the single crystal high-temperature alloy blade from the vacuum heat treatment furnace, and directly mechanically polish part of the blade;

Step 3: Clean the mechanically polished single crystal high-temperature alloy blades, and then use local electrolytic processing or chemical corrosion to remove traces of mechanical polishing;

Step 4: Perform solid solution aging treatment on the single crystal high-temperature alloy blades.

For the method of preventing partial recrystallization of single crystal high-temperature alloy blades of the present invention, the processing sequence is: recovery treatment, mechanical polishing, local electrolytic processing or chemical corrosion, and solid solution aging treatment. In this field, technicians generally believe that it is forbidden to use mechanical means to directly treat the blade body before solid solution aging treatment of single crystal superalloy blades. If the blade body is directly mechanically treated, it will promote recrystallization during the solid solution aging process. occur. However, the present invention overcomes the technical prejudice. It uses mechanical means to directly treat the blade body before the solid solution aging treatment of the blade, and combines the steps of restoring the blade before the mechanical treatment. Ultimately, it effectively avoids the solidification of single crystal high-temperature alloy blades. Recrystallization occurs during solution aging.

The gradual gradient recovery treatment from low temperature to high temperature can effectively recover the casting residual stress. When the residual stress is large, the core of recrystallized grains has been formed on the local surface of the single crystal blade. However, the structural characteristics of high-temperature alloy materials determine that the recrystallization grain boundary migration resistance before solid solution is large and difficult to grow. The controlling link in the recrystallization process of single crystal superalloy is nucleation.

Use hand-held electric, pneumatic or other polishing equipment to polish and repair the blades to remove areas with greater stress on the blade surface. After subsequent treatment, it can effectively prevent nucleation during the solid solution treatment process, or remove the core of recrystallized grains that have formed during the recovery process. .

Use non-mechanical polishing methods such as local electrolytic machining to remove all mechanical polishing traces to prevent the plastic deformation caused by polishing from nucleating during the solution treatment process. Since mechanical polishing will form a severe plastic deformation layer on the surface, although the thickness is thin, it will still promote the formation of recrystallized grains during the solution treatment process. For the above-mentioned mechanical polishing with careful operation, the deformed layer is very thin and can be effectively removed by non-mechanical methods.

Preferably, in step one, a gradient recovery treatment process is adopted that gradually progresses from low temperature to high temperature. The specific process is: heating from room temperature to 400-600°C at a heating rate of 2-5°C/min, and holding the temperature for 5-6 hours. ; Continue heating to 650-700°C at a heating rate of 2-5°C/min and keep warm for 4-5 hours; Continue heating to 870-900°C at a heating rate of 2-5°C/min and keep warm for 1-2 hours; At a heating rate of 2-5℃/min, continue to heat to 1100-1150℃ and keep warm for 1-2h; at a heating rate of 2-5℃/min, continue to heat to 1200-1250℃ and keep warm for 0.5-1h; at a heating rate of 2-5℃/min, keep warm for 0.5-1h; At a heating rate of 5°C/min, continue to heat to 1250-1280°C and keep warm for 0.5-1h; then cool to 280-300°C and come out of the oven.

In any of the above solutions, it is preferred that in step two, the mechanical polishing tool used is a handheld electric grinding tool or a handheld pneumatic grinding tool, the grinding head size is 80-120 mesh, and the grinding thickness is 0.02-0.05 mm.

In any of the above solutions, it is preferred that in step three, local electrolytic machining is used to remove traces of mechanical polishing, and the mechanically polished blades are partially electrolytically etched or polished.

In any of the above solutions, it is preferred that during the local electrolytic processing, the blade is used as the anode and the high-temperature alloy material is used as the cathode; the electrolyte ratio is NaCl:HCl:H ₂ O=1-3g:1-5ml :100ml, voltage is 5-30V, current is 7-15A, electrolytic processing time is 5-10s. During the electrolytic machining process, low voltage (such as 5-6V voltage) can be used for electrolytic corrosion, or high voltage can be used for electrolytic polishing. Due to manual operation, the voltage needs to be controlled within a safe voltage range below 36V. The present invention has proved through a large number of experiments that the proportion of electrolyte is controlled within the range of NaCl:HCl: _H2O =1-3g:1-5ml:100ml, and the electrolytic processing time is controlled within the range of 5-10s, which can ensure sufficient removal Processing marks, and will not damage areas without processing marks.

In any of the above solutions, preferably, in step three, chemical etching is used to remove traces of mechanical polishing, and all the blades are immersed in the corrosive liquid for corrosion. Since manual mechanical polishing is used, the depth of plastic deformation during processing is shallow, so chemical etching can also be used to remove all traces of mechanical polishing.

In any of the above solutions, it is preferred that during the chemical etching process, the ratio of the corrosive liquid is HCl:H ₂ O ₂ =100ml:10-15ml.

In any of the above solutions, it is preferred that in step four, the solid solution treatment process is: place the single crystal high-temperature alloy blade in a vacuum heat treatment furnace, heat from room temperature to 1290°C at a temperature rise rate of 10°C/min, and maintain the temperature. 1h; continue heating to 1300℃ at a heating rate of 10℃/min and keep warm for 2h; continue heating to 1315℃ at a heating rate of 10℃/min and keep warm for 4h.

In any of the above solutions, it is preferred that in step four, the aging treatment process is: after the solution treatment process is completed, forced cooling to 550°C; heating to 1120°C at a heating rate of 10°C/min, holding for 4 hours, and then Forced cooling to 550°C; heating to 870°C at a heating rate of 10°C/min, holding for 32 hours, then forced cooling to 300°C, and released from the oven.

The method of preventing partial recrystallization of single crystal high-temperature alloy blades of the present invention has the following beneficial effects:

1. First, a recovery treatment is performed, which can effectively remove the casting residual stress at the local stress concentration of the blade, or the stress concentration accumulates on the blade surface. Then, mechanical polishing is used to efficiently remove the local stress concentration structure, and finally local electrolytic machining or other non-concentrated parts are used. Mechanical polishing eliminates plastic deformation caused by mechanical polishing, thereby effectively avoiding recrystallization during the subsequent solution treatment process due to the large local casting residual stress concentration in the blade casting.

2. The use of mechanical polishing can achieve large margin processing and can effectively remove the large residual stress areas that exist locally in single crystal blades. The use of non-mechanical polishing methods such as electrolytic processing can further remove the plasticity caused by mechanical polishing. deformation, thereby effectively preventing the local occurrence of larger recrystallized grains in the single crystal blade.

Description of the drawings

Figure 1 is a photo of a blade in which recrystallization has been eliminated in a preferred embodiment of the method for preventing local recrystallization of single crystal high-temperature alloy blades according to the present invention. The processing sequence is: recovery treatment, mechanical polishing, electrolytic processing, and solid solution aging treatment. ;

Figure 2 is a photo of a blade that has recrystallized in a pair of examples of a method for preventing local recrystallization of single crystal high-temperature alloy blades that does not follow the present invention. The processing sequence is: mechanical polishing, electrolytic processing, recovery treatment, and solid solution aging treatment. .

Annotations in the figure: 1-Recrystallized grains.

Detailed ways

In order to further understand the content of the present invention, the present invention will be described in detail below with reference to specific embodiments.

Example 1:

According to a preferred embodiment of the method for preventing partial recrystallization of single crystal high-temperature alloy blades of the present invention, the following steps are included in order:

Step 1: Place the single crystal high-temperature alloy blade in a vacuum heat treatment furnace for recovery treatment;

Step 2: Take out the single crystal high-temperature alloy blade from the vacuum heat treatment furnace, and directly mechanically polish part of the blade;

Step 3: Clean the mechanically polished single crystal high-temperature alloy blades, and then use local electrolytic processing or chemical corrosion to remove traces of mechanical polishing;

Step 4: Perform solid solution aging treatment on the single crystal high-temperature alloy blades.

In step one, a gradient recovery process is adopted that gradually progresses from low temperature to high temperature. The specific process is: heating from room temperature to 400°C at a heating rate of 2°C/min, and holding for 6 hours; at a heating rate of 2°C/min, Continue to heat to 650°C and keep warm for 5 hours; continue to heat to 870°C at a heating rate of 2°C/min and keep warm for 2 hours; continue heating to 1100°C at a heating rate of 2°C/min and keep warm for 2 hours; keep warm for 2 hours at a heating rate of 2°C/min. At a heating rate of 1200°C, keep warm for 1 hour; at a heating rate of 2°C/min, continue heating to 1250°C and keep warm for 1 hour; cool to 280°C and come out of the oven.

In step two, a handheld electric grinding tool is used to directly mechanically polish part of the blade. The grinding head size is 80 mesh and the grinding thickness is 0.05mm.

In step three, local electrolytic machining is used to remove traces of mechanical polishing. During the electrolytic machining process, the blade is used as the anode and the high-temperature alloy material is used as the cathode; the electrolyte ratio is NaCl:HCl:H ₂ O=3g :5ml:100ml, the voltage is 5V, the current is 7A, and the electrochemical processing time is 10s.

In step four, the solid solution treatment process is: place the single crystal high-temperature alloy blade in a vacuum heat treatment furnace, heat it from room temperature to 1290°C at a heating rate of 10°C/min, and hold it for 1 hour; use a heating rate of 10°C/min. , continue to heat to 1300°C and keep warm for 2 hours; continue to heat to 1315°C at a heating rate of 10°C/min and keep warm for 4 hours. The aging treatment process is: after the solution treatment process is completed, forced cooling to 550°C; heating to 1120°C at a heating rate of 10°C/min, holding for 4 hours, and then forced cooling to 550°C; heating at a heating rate of 10°C/min. Heat to 870°C, keep warm for 32 hours, then force cool to 300°C and take it out of the oven. Forced cooling is performed by passing in argon gas after quenching.

In this embodiment, second-generation single crystal DD6 turbine blades are selected, and a total of 100 blades are selected for recrystallization elimination processing at the same time, focusing on the transition fillet area between the blade body and the edge plate, because there is a large residual stress in this area. As shown in Figure 1, after being processed by the method of this embodiment, local recrystallization of the blades is completely eliminated, and the pass rate reaches more than 98%, that is, 98 blades out of 100 blades have completely eliminated recrystallization.

For the method of preventing partial recrystallization of single crystal high-temperature alloy blades in this embodiment, the processing sequence is: recovery treatment, mechanical polishing, electrolytic processing, and solid solution aging treatment. In this field, technicians generally believe that it is forbidden to use mechanical means to directly treat the blade body before solid solution aging treatment of single crystal superalloy blades. If the blade body is directly mechanically treated, it will promote recrystallization during the solid solution aging process. occur. However, this embodiment overcomes the technical bias and uses mechanical means to directly treat the blade body before the solid solution aging treatment, combined with the steps of restoring the blade before mechanical treatment, which ultimately effectively avoids the problem of single crystal high-temperature alloy blades being damaged. Recrystallization occurs during solid solution aging.

The gradual gradient recovery treatment from low temperature to high temperature can effectively recover the casting residual stress. When the residual stress is large, the core of recrystallized grains has been formed on the local surface of the single crystal blade. Use hand-held electric polishing equipment to polish and repair the blades to remove areas with greater stress on the blade surface. After subsequent treatment, it can effectively prevent nucleation during the solid solution treatment process, or remove the core of recrystallized grains that have formed during the recovery process. Local electrolytic machining is used to completely remove traces of mechanical polishing and prevent the plastic deformation caused by polishing from nucleating during the solid solution treatment process.

Example 2:

According to another preferred embodiment of the method for preventing partial recrystallization of single crystal high-temperature alloy blades according to the present invention, the process sequence, equipment used, principles, beneficial effects, etc. are basically the same as those of Embodiment 1, except that:

In step one, a gradient recovery process is used that gradually progresses from low temperature to high temperature. The specific process is: heating from room temperature to 500°C at a heating rate of 3°C/min, and holding for 5.5 hours; heating at a heating rate of 3°C/min. , continue to heat to 680°C and keep warm for 4.5h; continue to heat to 885°C at a heating rate of 3°C/min and keep warm for 1.5h; continue heating to 1125°C at a heating rate of 3°C/min and keep warm for 1.5h; At a heating rate of 3℃/min, continue to heat to 1225℃ and hold for 0.75h; at a heating rate of 3℃/min, continue to heat to 1265℃ and hold for 0.75h; cool to 290℃ with the furnace and release.

In step two, a handheld electric grinding tool is used to directly mechanically polish part of the blade. The grinding head size is 120 mesh and the grinding thickness is 0.02mm.

In step three, electrolytic machining is used to remove traces of mechanical polishing. During the electrolytic machining process, the blade is used as the anode and the high-temperature alloy material is used as the cathode; the electrolyte ratio is NaCl:HCl:H ₂ O=1g: 3ml: 100ml, the voltage is 15V, the current is 15A, and the electrolytic processing time is 8s.

Embodiment three:

According to another preferred embodiment of the method for preventing partial recrystallization of single crystal high-temperature alloy blades according to the present invention, the process sequence, equipment used, principles, beneficial effects, etc. are basically the same as those of Embodiment 1, except that:

In step one, a gradient recovery process is adopted that gradually progresses from low temperature to high temperature. The specific process is: heating from room temperature to 600°C at a heating rate of 5°C/min, and holding for 5 hours; at a heating rate of 5°C/min, Continue to heat to 700°C and keep warm for 4 hours; continue to heat to 900°C at a heating rate of 5°C/min and keep warm for 1 hour; continue heating to 1150°C at a heating rate of 5°C/min and keep warm for 1 hour; continue heating to 900°C at a heating rate of 5°C/min and keep warm for 1 hour. At a heating rate of 1250℃, keep warm for 0.5h; at a heating rate of 5℃/min, continue heating to 1280℃ and keep warm for 0.5h; cool to 300℃ with the furnace and take it out.

In step two, a handheld electric grinding tool is used to directly mechanically polish part of the blade. The grinding head size is 120 mesh and the grinding thickness is 0.03mm.

In step three, electrolytic machining is used to remove traces of mechanical polishing. During the electrolytic machining process, the blade is used as the anode and the high-temperature alloy material is used as the cathode; the electrolyte ratio is NaCl:HCl:H ₂ O=2g: 1ml: 100ml, the voltage is 10V, the current is 12A, and the electrolytic processing time is 5s.

Embodiment 4:

According to another preferred embodiment of the method for preventing partial recrystallization of single crystal high-temperature alloy blades according to the present invention, the process sequence, equipment used, principles, beneficial effects, etc. are basically the same as those in Embodiments 1 to 3, except that:

In the third step, chemical etching is used to remove traces of mechanical polishing, and all the blades are immersed in the corrosive liquid for corrosion. The ratio of the corrosive liquid is HCl:H ₂ O ₂ =100ml:10ml.

In this embodiment, second-generation single crystal DD6 turbine blades are selected, and a total of 100 blades are selected for recrystallization elimination processing at the same time, focusing on the transition fillet area between the blade body and the edge plate, because there is a large residual stress in this area. After being processed by the method of this embodiment, local recrystallization of the blades is completely eliminated, and the pass rate reaches more than 95%, that is, 95 blades out of 100 blades have completely eliminated recrystallization.

Embodiment five:

According to another preferred embodiment of the method for preventing partial recrystallization of single crystal high-temperature alloy blades according to the present invention, the process sequence, equipment used, principles, beneficial effects, etc. are basically the same as those of Embodiment 4, except that:

In the third step, chemical corrosion is used to remove traces of mechanical polishing, and all the blades are immersed in a corrosive liquid for corrosion. The ratio of the corrosive liquid is HCl:H ₂ O ₂ =100ml:15ml.

Comparative Example 1:

Comparative Example 1 was not processed according to the method of preventing local recrystallization of single crystal high-temperature alloy blades of the present invention. The processing sequence of Comparative Example 1 was: mechanical polishing, electrolytic processing, recovery treatment, and solid solution aging treatment.

In this comparative example, the process parameters and equipment used in the four stages of mechanical polishing, electrolytic machining, recovery treatment, and solution aging treatment are exactly the same as those in the first embodiment, except that the processing sequence is different.

In this comparison example, second-generation single crystal DD6 turbine blades were selected, and a total of 100 blades were selected for recrystallization elimination processing at the same time, focusing on the transition fillet area between the blade body and the edge plate, because there is a large residual stress in this area. As shown in Figure 2, after being processed by the method of this comparative example, the blade qualification rate is only 48%, that is, only 48 blades out of 100 blades have completely eliminated recrystallization. The recrystallized crystals can be clearly seen from Figure 2. 1 grain.

Comparative Example 2:

Comparative Example 2 was not processed according to the method of preventing local recrystallization of single crystal high-temperature alloy blades of the present invention. The processing sequence of Comparative Example 2 was: mechanical polishing, electrolytic processing, and solid solution aging treatment.

In this comparative example, the process parameters and equipment used in the three stages of mechanical polishing, electrolytic processing, and solution aging treatment are exactly the same as those in Example 1, except that no recovery treatment is performed.

In this comparison example, second-generation single crystal DD6 turbine blades were selected, and a total of 100 blades were selected for recrystallization elimination processing at the same time, focusing on the transition fillet area between the blade body and the edge plate, because there is a large residual stress in this area. After being processed by the method of this comparative example, the blade qualification rate is only 13%, that is, only 13 blades out of 100 blades have completely eliminated recrystallization.

Special note: The technical solution of the present invention involves many parameters, and the synergy between each parameter needs to be comprehensively considered in order to obtain the beneficial effects and significant progress of the present invention. Moreover, the value range of each parameter in the technical solution was obtained through a large number of tests. For each parameter and the combination of each parameter, the inventor has recorded a large amount of test data. Due to space limitations, the specific test data will not be disclosed here.

It is easy for those skilled in the art to understand that the method for preventing local recrystallization of single crystal high-temperature alloy blades of the present invention includes any combination of the above-mentioned content of the invention and the specific embodiments of the description of the present invention and the various parts shown in the drawings. The length is limited. In order to make the description concise, each scheme composed of these combinations is not described one by one. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims (4)

1. A method for preventing local recrystallization of a single crystal superalloy blade comprises the following steps in sequence:

step one: placing the monocrystal superalloy blade into a vacuum heat treatment furnace for recovery treatment;

step two: taking out the single-crystal superalloy blade from the vacuum heat treatment furnace, and directly mechanically polishing and grinding part of the blade;

step three: cleaning the mechanically polished single-crystal superalloy blade, and removing mechanically polished traces by adopting a local electrolytic machining or chemical corrosion mode;

step four: carrying out solid solution aging treatment on the monocrystal superalloy blade;

in the first step, a gradient recovery treatment process gradually progressing from low temperature to high temperature is adopted, and the specific process is that the temperature is heated to 400-600 ℃ from room temperature at a heating rate of 2-5 ℃/min, and the temperature is kept for 5-6h; continuously heating to 650-700 ℃ at a heating rate of 2-5 ℃/min, and preserving heat for 4-5h; continuously heating to 870-900 ℃ at the heating rate of 2-5 ℃/min, and preserving heat for 1-2h; continuously heating to 1100-1150 ℃ at a heating rate of 2-5 ℃/min, and preserving heat for 1-2h; continuously heating to 1200-1250 ℃ at a heating rate of 2-5 ℃/min, and preserving heat for 0.5-1h; continuously heating to 1250-1280 ℃ at a heating rate of 2-5 ℃/min, and preserving heat for 0.5-1h; cooling to 280-300 ℃ along with the furnace, and discharging;

in the second step, the adopted mechanical polishing tool is a hand-held electric grinding tool or a hand-held pneumatic grinding tool, the granularity of the grinding head is 80-120 meshes, and the polishing thickness is 0.02-0.05mm;

in the third step, in the local electrolytic machining process, the blade is used as an anode, and a high-temperature alloy material is used as a cathode; the electrolyte is prepared from NaCl, HCl and H ₂ O=1-3 g:1-5ml:100ml, voltage 5-30V, current 7-15A, electrolytic processing time 5-10s.

2. The method for preventing localized recrystallization of single crystal superalloy blades according to claim 1, wherein: and thirdly, removing the trace of mechanical polishing by adopting a local electrolytic machining mode, and carrying out electrolytic corrosion or electrolytic polishing on the local part of the blade subjected to mechanical polishing.

3. The method for preventing localized recrystallization of single crystal superalloy blades according to claim 1, wherein: and thirdly, removing the trace of mechanical polishing and grinding by adopting a chemical corrosion mode, and completely soaking the blade in a corrosion liquid for corrosion.

4. A method of preventing localized recrystallization of a single crystal superalloy blade according to claim 3, wherein: in the chemical etching process, the ratio of the etching liquid is HCl to H ₂ O ₂ ＝100ml:10-15ml。