A heat treatment method for compressor impeller made of ASTM A705-630 material

Abstract

The invention discloses a heat treatment method for a compressor impeller made of ASTM A705-630 material, comprising: preliminary heat treatment: performing solution treatment and primary aging treatment on the wheel cover and wheel disc of the ASTM A705-630 material impeller before welding; welding the impeller: welding the wheel cover and wheel disc after the preliminary heat treatment to form an impeller; stress relief treatment: performing stress relief treatment on the impeller; performance heat treatment: performing secondary aging treatment, cold treatment and tertiary aging treatment on the impeller after the stress relief treatment. The heat treatment method for the compressor impeller made of ASTM A705-630 material of the invention can not only reduce the deformation problem of the impeller during the heat treatment process, but also improve the organizational structure stability of the impeller material, solve the problem of the impeller's dimensional deviation being too accurate in an overspeed test, and provide a guarantee for the safe operation of the compressor.

Description

Technical Field

[0001] The invention relates to the technical field of heat treatment, and in particular to a heat treatment method for a compressor impeller made of ASTM A705-630 material. Background Art

[0002] ASTM A705-630 steel is an American grade. Since this steel is low in carbon, high in chromium, and contains copper, its martensitic transformation temperature is higher than room temperature. After martensitic transformation and aging treatment, a dispersed copper-rich phase can be precipitated in the martensitic matrix, further improving the strength.

[0003] The traditional heat treatment scheme for ASTM A705-630 steel is solution treatment + aging treatment. The compressor impeller adopts the traditional heat treatment process, that is, the welded impeller is subjected to solution treatment + aging treatment. After the traditional heat treatment, the mechanical properties of the impeller have met the design requirements. According to the API 617 standard, the impeller needs to undergo an overspeed test before assembly to check the deformation and surface quality of the impeller. After the overspeed test of the impeller after traditional heat treatment, the dimensional deviation before and after the overspeed test often exceeds the standard requirements. The analysis shows that the main reason is that some unstable tissues undergo organizational transformation after the heat treatment of the material, causing the impeller structure to deform, posing a hidden danger to the safe operation of the machine owner. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a heat treatment method for a compressor impeller made of ASTM A705-630 material, so that the dimensional deviation of the heat-treated impeller before and after an overspeed test meets the standard requirements.

[0005] In order to solve the above problems, the present invention provides a heat treatment method for a compressor impeller made of ASTM A705-630 material, comprising:

[0006] Preparatory heat treatment, solution treatment and primary aging treatment of the impeller cover and impeller disc of ASTM A705-630 material before welding;

[0007] Welding the impeller, welding the wheel cover and wheel disc after the preliminary heat treatment to form the impeller;

[0008] Stress relief treatment: performing stress relief treatment on the impeller;

[0009] Performance heat treatment, the impeller after the stress relief treatment is subjected to secondary aging treatment, cold treatment and tertiary aging treatment.

[0010] Furthermore, the solution treatment temperature is 1026-1054° C., the holding time is ≥2 hours, and then cooled to room temperature.

[0011] Furthermore, the solution treatment further comprises: first heating to 800-900°C, keeping the temperature for ≥1h, heating to the solution treatment temperature at a rate of ≤100°C / h, keeping the temperature, and cooling to room temperature with water.

[0012] Furthermore, the primary aging treatment is: after the solution treatment, the temperature is kept at 600-640° C. for ≥5 h, and then air-cooled to room temperature.

[0013] Furthermore, the stress relief treatment is: heating at a rate of ≤50°C / h, keeping the temperature at 600-640°C for ≥5h, and then air cooling to room temperature.

[0014] Furthermore, the secondary aging treatment is: at a temperature of 800-900° C., keeping the temperature for ≥ 2 hours.

[0015] Furthermore, the secondary aging treatment also includes: heating at a rate of ≤70°C / h, keeping the temperature, and then oil cooling to room temperature.

[0016] Furthermore, the cold treatment is, after the secondary aging treatment, keeping the temperature at -50 to -75°C for ≥2h.

[0017] Furthermore, the cold treatment also includes: cooling at a rate of 2°C / min, and naturally heating to room temperature after heat preservation.

[0018] Furthermore, the three aging treatments are as follows: after the cold treatment, heating at a rate of ≤70°C / h, keeping the temperature at 480-635°C for ≥4h, and air cooling to room temperature after keeping the temperature.

[0019] The present invention provides a heat treatment method for a compressor impeller made of ASTM A705-630 material. In view of the complexity of the impeller structure, the present invention breaks the traditional inherent thinking and creatively proposes to subject the impeller cover and the impeller disc to high-temperature solution treatment and primary aging treatment, and reserve the dimensional deviation caused by the high-temperature solution treatment and the primary aging treatment, and then weld them into an impeller. After welding the impeller, no high-temperature solution treatment is performed, thereby reducing the deformation of the impeller during the high-temperature solution treatment. In addition, the impeller after welding is subjected to secondary aging treatment and cold treatment, which effectively reduces the unstable austenite content of the impeller after heat treatment, solves the problem that the dimensional deviation of the impeller exceeds the standard requirement value before and after the overspeed test, and improves the quality of the impeller. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A flow chart of a heat treatment method for a compressor impeller made of ASTM A705-630 material provided in an embodiment of the present invention.

[0021] Figure 2A schematic diagram of impeller coordinate inspection dimensions in a heat treatment method for a compressor impeller made of ASTM A705-630 material provided in an embodiment of the present invention.

[0022] Figure 3 A schematic diagram of the inspection dimensions of an impeller before and after an overspeed test in a heat treatment method for an ASTM A705-630 material compressor impeller provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0023] See also Figure 1 The embodiment of the present invention provides a heat treatment method for a compressor impeller made of ASTM A705-630 material, comprising:

[0024] The present invention provides a heat treatment method for a compressor impeller made of ASTM A705-630 material, comprising:

[0025] Preparatory heat treatment, solution treatment and primary aging treatment of the impeller cover and impeller disc of ASTM A705-630 material before welding;

[0026] Welding the impeller, welding the wheel cover and wheel disc after the preliminary heat treatment to form the impeller;

[0027] Stress relief treatment: performing stress relief treatment on the impeller;

[0028] Performance heat treatment, the impeller after the stress relief treatment is subjected to secondary aging treatment, cold treatment and tertiary aging treatment.

[0029] The heat treatment method for a compressor impeller made of ASTM A705-630 material provided in an embodiment of the present invention breaks the traditional inherent thinking in view of the complexity of the impeller structure and creatively proposes to subject the impeller cover and the impeller disc to high-temperature solution treatment and primary aging treatment, and reserve the dimensional deviation caused by the high-temperature solution treatment and primary aging treatment, and then weld them into an impeller. After welding the impeller, no high-temperature solution treatment is performed, thereby reducing the deformation of the impeller during the high-temperature solution treatment. In addition, the impeller after welding is subjected to secondary aging treatment and cold treatment, which effectively reduces the unstable austenite content of the impeller after heat treatment, solves the problem that the dimensional deviation of the impeller exceeds the standard requirement value before and after the overspeed test, and improves the quality of the impeller.

[0030] Furthermore, the solution treatment temperature is 1026-1054° C., the holding time is ≥2 hours, and then cooled to room temperature.

[0031] After solution treatment, alloy elements and carbides are fully integrated into austenite, and martensite and residual austenite are formed after cooling. If the solution treatment temperature is lower than 1026℃, the phase cannot be fully dissolved into austenite. If the temperature is higher than 1054℃, the structure of the material after heat treatment will be coarse, which will affect the mechanical properties of the material in the later stage and cause energy waste.

[0032] Furthermore, the solution treatment further comprises: first heating to 800-900°C, keeping the temperature for ≥1h, heating to the solution treatment temperature at a rate of ≤100°C / h, keeping the temperature, and cooling to room temperature with water.

[0033] During the solution treatment process, the temperature is kept at 800-900℃ and the heating rate is controlled at ≤100℃ / h to improve the temperature uniformity of the solution treatment process, ensure that the furnace temperature is consistent with the temperature of the parts, reduce the deformation of the material during the heat treatment process, and prevent the material from cracking. The rapid cooling method of water cooling is mainly to prevent the second phase from precipitating during the cooling process and affecting the mechanical properties of the subsequent materials.

[0034] Furthermore, the primary aging treatment is: after the solution treatment, the temperature is kept at 600-640° C. for ≥5 h, and then air-cooled to room temperature.

[0035] After the material has been aged once, dispersed intermetallic compounds are precipitated from the martensite to adjust the hardness of the material to meet the processing requirements. When the aging temperature is higher than 640°C, which exceeds the phase transition point Ac1 of the material, secondary martensite is formed in the material structure, the hardness increases, and the processing becomes difficult; when the aging temperature is lower than 600°C, the precipitated phase of the material is coherent with the matrix, the strength and hardness of the material are high, and it is not conducive to subsequent processing.

[0036] Furthermore, the stress relief treatment is: heating at a rate of ≤50°C / h, keeping the temperature at 600-640°C for ≥5h, and then air cooling to room temperature.

[0037] The purpose of stress relief is to eliminate the internal stress of the impeller during welding. If the temperature of stress relief is lower than 600℃, the internal stress will be less eliminated; if the temperature is higher than 640℃, secondary martensite will form in the material, generating new internal stress. Control the heating rate to ≤50℃ / h to ensure the uniformity of the impeller temperature during stress relief. Air cool to room temperature to prevent excessive second phase formation and internal stress.

[0038] Furthermore, the secondary aging treatment is: at a temperature of 800-900°C, keeping the temperature for ≥2h. The secondary aging treatment also includes: heating at a rate of ≤70°C / h, keeping the temperature, and then oil cooling to room temperature.

[0039] The purpose of secondary aging treatment is to dissolve carbon and alloy elements in austenite and reduce the concentration of alloy elements in the matrix. During cooling, due to the decrease in austenite stability, the martensite transformation point increases, so that more martensite is obtained and the unstable austenite content is reduced. When the secondary aging treatment temperature is higher than 900℃, the material strength is high, but the toughness becomes poor; when the temperature is lower than 800℃, the material strength cannot meet the design requirements.

[0040] The temperature is raised at a rate of ≤70℃ / h to improve the temperature uniformity of the secondary aging process and ensure that the furnace temperature is consistent with the temperature of the parts. After insulation, oil cooling to room temperature reduces the formation of the second phase and ensures that the material forms the corresponding martensitic structure.

[0041] Furthermore, the cold treatment is: after the secondary aging treatment, the temperature is kept at -50 to -75°C for ≥2h. The cold treatment also includes: cooling at a speed of 2°C / min, and naturally heating to room temperature after keeping the temperature.

[0042] The purpose of cold treatment is to transform the residual austenite that has not yet transformed at room temperature into martensite, so as to further reduce the content of unstable austenite. When the cold treatment temperature is lower than -75℃, the content of unstable austenite does not change significantly, and it causes energy waste, prolongs the time for the material to return to room temperature, and affects the production cycle; when the temperature is higher than -50℃, a lot of unstable austenite still exists.

[0043] Cooling at a rate of 2°C / min is to improve the temperature uniformity of the cold treatment process and ensure that the furnace temperature is consistent with the temperature of the parts. After insulation, the temperature is naturally raised to room temperature to reduce material deformation during the heating process.

[0044] Furthermore, the three aging treatments are as follows: after the cold treatment, heating at a rate of ≤70°C / h, keeping the temperature at 480-635°C for ≥4h, and air cooling to room temperature after keeping the temperature.

[0045] The purpose of triple aging is to adjust the comprehensive mechanical properties of the material to meet the design requirements. If the temperature is higher than 635°C, the strength of the material will be low and cannot meet the design requirements; if the temperature is lower than 480°C, the impact toughness of the material will be poor.

[0046] In summary, the embodiment of the present invention optimizes and improves the traditional heat treatment process of ASTM A705-630 steel, namely, solution treatment + aging, and proposes to subject the wheel cover and disc of the impeller to solution treatment and aging treatment, while the welded impeller is only subjected to aging treatment and cold treatment. The impeller is not subjected to high-temperature solution treatment after welding, thereby reducing the deformation of the impeller during the heat treatment process and improving the quality of the impeller; and by adding high-temperature aging treatment and cold treatment, the unstable austenite in the impeller heat treatment process is effectively reduced, the organizational structure stability of the impeller material is improved, and it is ensured that the dimensional deviation of the impeller before and after the overspeed test does not exceed the standard requirements, thereby providing a guarantee for the safe operation of the compressor.

[0047] Example 1 A heat treatment method for a compressor impeller made of ASTM A705-630 material

[0048] The impeller with a diameter of Φ450mm before heat treatment is produced. The heat treatment process includes: preliminary heat treatment of the impeller cover and disc, welding of the impeller, stress relief of the impeller after welding, and performance heat treatment after stress relief.

[0049] Preparatory heat treatment of impeller cover and impeller disc:

[0050] (1) Solution treatment: The impeller cover and disc forgings are heated to 800°C and kept at this temperature for 1 hour. The temperature is then raised to 1040°C at a rate of 70°C / h, kept at this temperature for 2 hours, and then cooled to room temperature with water.

[0051] (2) Primary aging treatment: After solution treatment, the forgings are heated to 620°C, kept at this temperature for 5 h, and then air-cooled to room temperature.

[0052] Welding impeller: The wheel cover and wheel disc that have been prepared for heat treatment are welded to form an impeller.

[0053] Stress relief treatment after impeller welding:

[0054] (1) Stress relief after welding: The welded impeller is heated to 620℃ at a rate of 40℃ / h, kept at this temperature for 5h and then air-cooled to room temperature.

[0055] Performance of impeller after stress relief heat treatment:

[0056] (2) Secondary aging treatment: The welded impeller is heated to 850°C at a rate of 40°C / h, kept at that temperature for 2h, and then oil-cooled to room temperature;

[0057] (3) Cold treatment: After high temperature aging treatment, the impeller is cooled to -50°C at a rate of 2°C / min, kept at this temperature for 2 hours, and then naturally heated to room temperature;

[0058] (4) Three aging treatments: The impeller after cold treatment is heated to 550°C at a rate of 30°C / h, kept at that temperature for 4h, and then air-cooled to room temperature.

[0059] Mechanical properties of wheel cover after heat treatment: Rm: 1038Mpa; Rp0.2: 970Mpa; A: 17%; Z: 60%; Kv2: 120 / 142 / 110J; HBW: 312, austenite content after heat treatment is 1.8%.

[0060] Mechanical properties of the wheel after heat treatment: Rm: 1026Mpa; Rp0.2: 954Mpa; A: 17%; Z: 62%; Kv2: 118 / 124 / 136J; HBW: 316, austenite content after heat treatment is 1.5%.

[0061] See also Figure 2 In Table 1, before treatment refers to: the preliminary heat treatment of the impeller cover and the wheel disc and after welding the impeller, and after treatment refers to: after the preliminary heat treatment of the impeller cover and the wheel disc, welding the impeller, stress relief treatment and performance heat treatment. The impeller size changes are shown in Table 1. It can be seen that the impeller coordinate size changes are not obvious.

[0062] Table 1 Impeller coordinate size change table of Example 1

[0063]

[0064] See also Figure 3 , Impeller outer diameter before overspeed test Size is 450mm, mouth diameter The size is 324.98mm, the inner hole diameter The size is 168.03mm.

[0065] Impeller outer diameter after overspeed test Size is 450mm, mouth diameter The size is 324.98mm, the inner hole diameter The size is 168.04mm.

[0066] The dimensional deviation of the impeller before and after over-rotation is 0mm for the outer diameter and 0% for the deviation; 0mm for the mouth ring diameter and 0% for the deviation; 0.01mm for the inner hole diameter and 0.006% for the deviation, which meets the standard requirements.

[0067] Comparative Example 1: Heat treatment method for a compressor impeller made of ASTM A705-630 material

[0068] The impeller with a diameter of Φ450mm before heat treatment is produced. The heat treatment includes: solution treatment and aging treatment after impeller welding stress relief.

[0069] (1) Solution treatment: The impeller is heated to 1038°C, kept at this temperature for 2 hours, and then cooled to room temperature with water;

[0070] (2) Aging treatment: The impeller is heated to 570°C, kept at this temperature for 4 hours, and then air-cooled to room temperature.

[0071] Mechanical properties of wheel cover after heat treatment: Rm: 1062Mpa; Rp0.2: 923Mpa; A: 15%; Z: 52%; Kv2: 100 / 106 / 90J; HBW: 322, austenite content after heat treatment is 6.3%.

[0072] The mechanical properties of the wheel after heat treatment are: Rm: 1058Mpa; Rp0.2: 936Mpa; A: 14%; Z: 50%; Kv2: 90 / 96 / 90J; HBW: 328, and the austenite content after heat treatment is 7.2%.

[0073] See also Figure 2 In Table 2, before treatment refers to: before impeller stress relief, solution treatment and aging treatment, and after treatment refers to: after impeller stress relief, solution treatment and aging treatment. The impeller size changes are shown in Table 2. It can be seen that the impeller coordinate size changes greatly.

[0074] Table 2 Impeller coordinate size change table of comparative example 1

[0075]

[0076] See also Figure 3 , Impeller outer diameter before overspeed test The size is 450.1mm, the diameter of the ring The size is 324.97mm, the inner diameter The size is 168.03mm.

[0077] Impeller outer diameter after overspeed test The size is 450.1mm, the diameter of the ring The size is 325.05mm, the inner hole diameter The size is 168.07mm.

[0078] The dimensional deviation of the impeller before and after over-rotation is 0mm in outer diameter, with a deviation of 0%; the difference in the ring diameter is 0.08mm, with a deviation of 0.025%; the difference in the inner hole diameter is 0.04mm, with a deviation of 0.024%. The deviations of the ring diameter and the inner hole diameter exceed the standard requirements.

[0079] Example 2 A heat treatment method for a compressor impeller made of ASTM A705-630 material

[0080] The impeller with a diameter of Φ900mm before heat treatment is produced. The heat treatment process includes preparatory heat treatment of impeller cover and disc, welding of impeller, stress relief of impeller after welding and performance heat treatment after stress relief.

[0081] Preparatory heat treatment of impeller cover and impeller disc:

[0082] (1) Solution treatment: The impeller cover and disc forgings are heated to 850°C and kept at this temperature for 2 hours. The temperature is then raised to 1035°C at a rate of 50°C / h, kept at this temperature for 5 hours, and then cooled to room temperature with water.

[0083] (2) Primary aging treatment: After solution treatment, the forgings are heated to 635°C, kept at this temperature for 15 h, and then air-cooled to room temperature.

[0084] Welding impeller: The wheel cover and wheel disc that have been prepared for heat treatment are welded to form an impeller.

[0085] Stress relief treatment after impeller welding:

[0086] (1) Stress relief after welding: The welded impeller is heated to 635℃ at a rate of 30℃ / h, kept at this temperature for 8h and then air-cooled to room temperature.

[0087] Impeller performance after stress relief heat treatment

[0088] (2) Secondary aging treatment: The welded impeller is heated to 850°C at a rate of 35°C / h, kept at that temperature for 3.5h, and then cooled to room temperature with oil;

[0089] (3) Cold treatment: After high temperature aging treatment, the impeller is cooled to -75°C at a rate of 2°C / min, kept at this temperature for 3.5 hours, and then naturally heated to room temperature;

[0090] (4) Three aging treatments: The impeller after cold treatment was heated to 510°C at a rate of 42°C / h, kept at that temperature for 6h, and then air-cooled to room temperature.

[0091] Mechanical properties of wheel cover after heat treatment: Rm: 1112Mpa; Rp0.2: 1038Mpa; A: 15%; Z: 40%; Kv2: 78 / 78 / 80J; HBW: 352, austenite content after heat treatment is 2.1%.

[0092] The mechanical properties of the wheel after heat treatment are: Rm: 1120Mpa; Rp0.2: 1042Mpa; A: 15%; Z: 44%; Kv2: 70 / 70 / 78J; HBW: 362, and the austenite content after heat treatment is 1.8%.

[0093] See also Figure 2 In Table 3, before treatment refers to: the preparatory heat treatment of the impeller cover and the wheel disc and after welding the impeller, and after treatment refers to: after the preparatory heat treatment of the impeller cover and the wheel disc, welding the impeller, stress relief treatment and performance heat treatment. The impeller size changes are shown in Table 3. It can be seen that the impeller coordinate size changes are not obvious.

[0094] Table 3 Impeller coordinate size change table of Example 2

[0095]

[0096] See also Figure 3 , Impeller outer diameter before overspeed test Size is 900mm, mouth diameter The size is 707.98mm, the inner hole diameter The size is 300.02mm.

[0097] Impeller outer diameter after overspeed test The size is 900.02mm, the diameter of the ring The size is 707.98mm, the inner hole diameter The size is 300.03mm.

[0098] The dimensional deviation of the impeller before and after over-rotation is 0.02mm in outer diameter and 0.002% in deviation; 0mm in mouth diameter and 0% in deviation; 0.01mm in inner hole diameter and 0.003% in deviation, which meets the standard requirements.

[0099] Comparative Example 2 Heat Treatment Method for a Compressor Impeller Made of ASTM A705-630 Material

[0100] The impeller with a diameter of Φ900mm before heat treatment is produced. The heat treatment process includes solution treatment and aging treatment after the impeller is welded to relieve stress.

[0101] (1) Solution treatment: The impeller is heated to 1042°C, kept at this temperature for 3.5 hours, and then cooled to room temperature with water;

[0102] (2) Aging treatment: The impeller is heated to 530°C, kept at this temperature for 6 hours, and then air-cooled to room temperature.

[0103] Mechanical properties of wheel cover after heat treatment: Rm: 1156Mpa; Rp0.2: 1012Mpa; A: 14%; Z: 48%; Kv2: 60 / 60 / 58J; HBW: 363, austenite content after heat treatment is 7.2%.

[0104] The mechanical properties of the wheel after heat treatment are: Rm: 1150Mpa; Rp0.2: 1022Mpa; A: 14%; Z: 52%; Kv2: 58 / 66 / 58J; HBW: 368, and the austenite content after heat treatment is 7.0%.

[0105] See also Figure 2 In Table 4, before treatment refers to: before impeller stress relief, solution treatment and aging treatment, and after treatment refers to: after impeller stress relief, solution treatment and aging treatment. The impeller size changes are shown in Table 4. It can be seen that the impeller coordinate size changes greatly.

[0106] Table 4 Impeller coordinate size change table of comparative example 2

[0107]

[0108] See also Figure 3 , Impeller outer diameter before overspeed test Size is 900mm, mouth diameter The size is 707.97mm, the inner hole diameter The size is 300.01mm.

[0109] Impeller outer diameter after overspeed test The size is 900.18mm, the diameter of the mouth ring The size is 708.19mm, the inner hole diameter The size is 300.28mm.

[0110] The dimensional deviation of the impeller before and after over-rotation is 0.18mm in outer diameter, with a deviation of 0.02%; the difference in the diameter of the mouth ring is 0.22mm, with a deviation of 0.031%; the difference in the inner hole diameter is 0.27mm, with a deviation of 0.09%. The deviations of the diameter of the mouth ring and the inner hole exceed the standard requirements.

[0111] It is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed. The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application. The above are only preferred implementation methods of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present application, and these improvements and variations should also be regarded as the protection scope of the present application.

Claims

1. A heat treatment method for compressor impeller made of ASTM A705-630 material. Features: include: Preparatory heat treatment, solution treatment and primary aging treatment of the impeller cover and impeller disc of ASTM A705-630 material before welding; Welding the impeller, welding the wheel cover and wheel disc after the preliminary heat treatment to form the impeller; Stress relief treatment: performing stress relief treatment on the impeller; Performance heat treatment, performing secondary aging treatment, cold treatment and tertiary aging treatment on the impeller after the stress relief treatment; Wherein, the solution treatment temperature is 1026-1054°C, the holding time is ≥2h, and then cooled to room temperature; The primary aging treatment is: after the solution treatment, the temperature is kept at 600-640°C for ≥5h, and then air-cooled to room temperature; The stress relief treatment is: keeping the temperature at 600-640°C for ≥5h, and then air cooling to room temperature; The secondary aging treatment is: at a temperature of 800-900°C, keeping warm for ≥2h; The cold treatment is to keep the temperature at -50 to -75°C for ≥2h after the secondary aging treatment; The three aging treatments are as follows: after the cold treatment, keeping the temperature at 480-635° C. for ≥4 hours, and then air cooling to room temperature.

2. The heat treatment method of the compressor impeller made of ASTM A705-630 material according to claim 1, Features: The solution treatment further comprises: first heating to 800-900°C, keeping the temperature for ≥1h, heating to the solution treatment temperature at a speed of ≤100°C / h, and cooling to room temperature with water after keeping the temperature.

3. The heat treatment method of the compressor impeller made of ASTM A705-630 material according to claim 1, Features: The stress relief treatment is performed by heating the temperature at a rate of ≤50°C / h.

4. The heat treatment method of the compressor impeller made of ASTM A705-630 material according to claim 1, Features: The secondary aging treatment further comprises: heating at a rate of ≤70°C / h, keeping the temperature and then oil cooling to room temperature.

5. The heat treatment method of the compressor impeller made of ASTM A705-630 material according to claim 1, Features: The cold treatment also includes: cooling at a rate of 2°C / min, and naturally heating to room temperature after heat preservation.

6. The heat treatment method of the compressor impeller made of ASTM A705-630 material according to claim 1, Features: The three aging treatments are heated at a rate of ≤70°C / h.

Images