GH625 alloy and heat treatment method and application thereof

Abstract

The invention relates to a heat treatment method for improving the high-temperature yield strength of a GH625 hot rolled plate, and belongs to the field of metal heat treatment. The GH625 alloy is a solid solution strengthening type high-temperature alloy with Cr, Mo and Nb as main strengthening elements and is widely applied to the industries of aviation, chemical engineering, nuclear power and the like. However, the high-temperature yield strength of the GH625 hot rolled plate cannot meet the specific technical standard after standard heat treatment in a traditional manufacturing process. Therefore, the invention provides a method for combining solid solution and aging heat treatment, so that the yield strength of the alloy is remarkably improved. The specific method comprises the steps of sample preparation, solid solution heat treatment, aging heat treatment and high-temperature tensile property testing. By means of the heat treatment method, the yield strength of the GH625 alloy is remarkably improved, and effective technical support is provided for application of the alloy under the high-temperature condition.

Description

Technical Field

[0001] The present invention relates to the field of metal heat treatment, and in particular to a GH625 alloy and a heat treatment method and application thereof. Background Art

[0002] GH625 alloy is an important high-temperature alloy, widely used in aerospace, nuclear energy, chemical industry, oil field and other industries. Its main elements are chromium (Cr), molybdenum (Mo) and niobium (Nb), and the alloy formed has good creep resistance and corrosion resistance in high temperature environment. GH625 alloy is usually used to manufacture key components that withstand high temperature and high pressure, such as gas turbine blades, nuclear reactor components, etc., and can maintain excellent mechanical properties at a high temperature of 950℃.

[0003] The traditional GH625 alloy manufacturing process mainly relies on a combination of vacuum induction melting and electroslag remelting, and the final plate is formed after forging and hot rolling. Although the plate can meet the technical standards of the chemical industry for yield strength after solution treatment, the existing technology is unable to meet the requirements of some special industries for temperatures greater than 320MPa, 275MPa, and 230mPa at 650℃, 750℃, and 850℃, respectively.

[0004] The existing heat treatment process usually adopts the method of solid solution treatment to improve the comprehensive properties of the alloy. However, this process has several significant defects:

[0005] Insufficient yield strength: The yield strength of GH625 alloy obtained after standard heat treatment under high temperature conditions cannot meet the technical standards, especially in demanding applications such as aviation and nuclear power.

[0006] Insufficient control of microstructure: Conventional heat treatment methods have limited effect in improving the microstructure of alloys, resulting in uneven distribution of precipitation phases inside the alloy, making it difficult to form an ideal strengthening structure, and thus unable to significantly improve high-temperature performance.

[0007] Residual stress problem: Due to the traditional processing method, the temperature gradient during the cooling process often leads to the formation of residual stress inside the material, which not only affects the long-term stability of the material, but may also cause fatigue damage under high temperature and high load conditions.

[0008] Therefore, it is urgent to design a GH625 alloy and a heat treatment method thereof to solve the problem that the yield strength of the GH625 alloy obtained by conventional methods in the prior art cannot meet the requirements of technical standards. Summary of the invention

[0009] The technical problem to be solved by the present invention is to provide a heat treatment method for GH625 alloy to solve the problem of insufficient high temperature yield strength caused by conventional manufacturing methods in the prior art, especially when the yield strength cannot meet industry standards in certain high temperature applications.

[0010] In order to solve the above technical problems, the present invention provides a heat treatment method of GH625 alloy, comprising the following steps:

[0011] S1: Take the alloy raw material to be heat treated, sample it and prepare it to obtain a tensile specimen;

[0012] S2: Solution heat treatment: heating the sample obtained in step S1 to 1100-1200° C., keeping the temperature for 15-30 minutes, and cooling;

[0013] S3: Aging heat treatment: The sample after the solution heat treatment in step S2 is heated to 600-700° C., kept at this temperature for 20-30 hours, and cooled to complete the heat treatment of the GH625 alloy.

[0014] Compared with the prior art, a heat treatment method for GH625 alloy in the present application has the following advantages: the traditional single heat treatment process in the prior art is changed to a combination of solution heat treatment and aging heat treatment. The direct technical principle is that through two stages of heat treatment, the alloy undergoes phase transformation and precipitation under different temperature conditions, forming a δ phase to strengthen the microstructure of the material, and significantly improves the high temperature yield strength of the alloy. This technical effect not only solves the problem of insufficient strength caused by traditional heat treatment methods, but also ensures the reliability of the alloy under high temperature conditions; specifically, the above-mentioned manufacturing method includes: first, improving the matrix strength of the alloy through solution heat treatment, and then further enhancing the high temperature performance of the material through the formation of precipitation phases during the aging heat treatment process. This process reflects the synergistic effect between the heat treatment steps, so that the GH625 alloy can meet the high temperature yield strength requirements of specific industries while maintaining the toughness and plasticity of the material.

[0015] In a possible implementation, in step S2, the temperature of the solution treatment is 1130-1150° C., and the holding time is 15-25 minutes.

[0016] In a possible implementation, in step S2, the temperature of the solution heat treatment is 1140° C., and the holding time is 20 minutes.

[0017] Compared with the existing technology, the above technical scheme can improve the distribution uniformity of the strengthening phase in the alloy by accurately controlling the temperature and holding time of the solution heat treatment, further narrowing the temperature range and the holding time range, and ultimately improving the mechanical properties of the material.

[0018] In a possible implementation, in step S3, the temperature of the aging heat treatment is 640-660° C., and the holding time is 22-26 hours.

[0019] In a possible implementation, in step S3, the temperature of the aging heat treatment is 650° C., and the holding time is 24 hours.

[0020] Compared with the prior art, the above technical solution can further promote the precipitation of the δ phase in the alloy by optimizing the aging heat treatment conditions and further limiting the aging temperature and holding time, thereby further improving the high temperature yield strength of the GH625 alloy and making it better adaptable to high temperature applications.

[0021] In a possible implementation, in steps S2 and S3, the heating device is an electric heating furnace.

[0022] Compared with the prior art, the above technical solution can ensure heating uniformity and temperature stability during the heat treatment process, thereby improving the overall performance of the GH625 alloy.

[0023] In a possible implementation manner, in steps S2 and S3, the cooling method is: air cooling after exiting the furnace.

[0024] Compared with the existing technology, the above technical solution can ensure that the alloy forms a good microstructure and strengthening phase during the cooling process after heat treatment, thereby improving the high temperature yield strength of the material.

[0025] Another technical problem to be solved by the present invention is to provide a GH625 alloy to solve the problem of insufficient yield strength of conventional alloys.

[0026] In order to solve the above technical problems, the present invention provides a GH625 alloy, characterized in that the GH625 alloy is obtained by any one of the heat treatment methods of claims 1 to 7, and the components of the GH625 alloy include: C: 0.047-0.050%, Mn: 0.010-0.015%, Si: 0.040-0.045%, S: 0.0010-0.0020%, P: 0.0030-0.0040%, Nb+Ta: 3.50-3.70%, Cr: 22.00-22.50%, Al: 0.22-0.25%, Ti: 0.18-0.22%, Co: 0.045-0.050%, Mo: 9.00-9.10%, Fe: 0.15-0.20%, Cu: 0.0090-0,0100%, and the balance is Ni and other inevitable impurities.

[0027] Compared with the prior art, the heat treatment method of a GH625 alloy in this application has the following advantages: the single alloy formula in the prior art is changed to an optimized alloy composition design to achieve synergy between the elements. By optimizing the alloy formula, the strength and toughness of the material are significantly improved, and the linkage effect of solid solution and aging heat treatment is combined to comprehensively solve the problem of insufficient high-temperature yield strength mentioned in the background technology. This technical solution not only ensures the stable performance of the GH625 alloy under high temperature conditions, but also provides reliable guarantee for the application of the alloy in harsh environments such as high temperature and high pressure.

[0028] In a possible implementation manner, the composition of the GH625 alloy includes, by mass ratio, C: 0.049%, Mn: 0.013%, Si: 0.044%, S: 0.0016%, P: 0.0037%, Nb+Ta: 3.68%, Cr: 22.25%, Al: 0.24%, Ti: 0.20%, Co: 0.047%, Mo: 9.04%, Fe: 0.19%, Cu: 0.0098%, and the balance is Ni and other inevitable impurities.

[0029] Compared with the prior art, the above technical solution further optimizes the alloy composition, further improves the strength and toughness of the material, and solves the problem of insufficient yield strength of conventional alloys.

[0030] Another technical problem to be solved by the present invention is to provide applications of the GH625 alloy, which includes applying the GH625 alloy to equipment manufacturing in aviation, chemical industry, nuclear power, and oil fields.

[0031] By applying the above-mentioned GH625 alloy to the equipment manufacturing in aviation, chemical industry, nuclear power, and oil field, the yield performance of the equipment in high-temperature applications is improved, and it also has strong mechanical strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is the δ phase diagram of the grain boundary precipitation after aging treatment of GH625 plate. DETAILED DESCRIPTION

[0033] First, those skilled in the art should understand that these implementations are only used to explain the technical principles of the embodiments of the present application, and are not intended to limit the protection scope of the embodiments of the present application. Those skilled in the art can make adjustments to them as needed to adapt to specific application scenarios.

[0034] The present invention provides a heat treatment method for GH625 alloy, comprising the following steps:

[0035] S1: Take the alloy raw material to be heat treated, sample it and prepare it to obtain a tensile specimen;

[0036] S2: Solution heat treatment: heating the sample obtained in step S1 to 1100-1200° C., keeping the temperature for 15-30 minutes, and cooling;

[0037] S3: Aging heat treatment: The sample after the solution heat treatment in step S2 is heated to 600-700° C., kept at this temperature for 20-30 hours, and cooled to complete the heat treatment of the GH625 alloy.

[0038] As a preferred solution, in step S2, the temperature of the solution treatment is 1130-1150°C, and the holding time is 15-25 minutes.

[0039] As a preferred solution, in step S2, the temperature of the solution heat treatment is 1140° C. and the holding time is 20 minutes.

[0040] As a preferred solution, in step S3, the temperature of the aging heat treatment is 640-660° C., and the holding time is 22-26 hours.

[0041] As a preferred solution, in step S3, the temperature of the aging heat treatment is 650° C. and the holding time is 24 hours.

[0042] As a preferred solution, in steps S2 and S3, the heating equipment is an electric heating furnace.

[0043] As a preferred solution, in steps S2 and S3, the cooling method is: air cooling after exiting the furnace.

[0044] The present invention also provides a GH625 alloy, which is obtained by the above-mentioned heat treatment method, and the components of the GH625 alloy include: C: 0.047-0.050%, Mn: 0.010-0.015%, Si: 0.040-0.045%, S: 0.0010-0.0020%, P: 0.0030-0.0040%, Nb+Ta: 3.50-3.70%, Cr: 22.00-22.50%, Al: 0.22-0.25%, Ti: 0.18-0.22%, Co: 0.045-0.050%, Mo: 9.00-9.10%, Fe: 0.15-0.20%, Cu: 0.0090-0,0100%, and the balance is Ni and other inevitable impurities.

[0045] As a preferred solution, the composition of the GH625 alloy includes, by mass ratio, C: 0.049%, Mn: 0.013%, Si: 0.044%, S: 0.0016%, P: 0.0037%, Nb+Ta: 3.68%, Cr: 22.25%, Al: 0.24%, Ti: 0.20%, Co: 0.047%, Mo: 9.04%, Fe: 0.19%, Cu: 0.0098%, and the balance is Ni and other inevitable impurities.

[0046] The following further describes the technical solution of the present invention in combination with the above technical solution, and provides an embodiment combined with specific data:

[0047] Embodiment 1:

[0048] This embodiment provides a GH625 alloy and a heat treatment method and application thereof. The GH625 alloy includes the following components:

[0049] C: 0.049%, Mn: 0.013%, Si: 0.044%, S: 0.0016%, P: 0.0037%, Nb+Ta: 3.68%, Cr: 22.25%, Al: 0.24%, Ti: 0.20%, Co: 0.047%, Mo: 9.04%, Fe: 0.19%, Cu: 0.0098%, the remainder is Ni and other inevitable impurities.

[0050] The application includes applying the GH625 alloy to equipment manufacturing in aviation, chemical industry, nuclear power, and oil fields.

[0051] The heat treatment method of the GH625 alloy comprises:

[0052] S1: Take the alloy raw material to be heat treated, sample on the plate, process the high temperature tensile specimen, and obtain the tensile specimen;

[0053] S2: Solution heat treatment: Place the sample processed in step S1 into a chamber-type electric heating furnace, heat it to 1140°C and keep it warm for 20 minutes, then take the sample out of the heating furnace and air cool it to room temperature;

[0054] S3: Aging heat treatment: The sample after the solution treatment is put back into the chamber electric heating furnace, heated to 650°C for 24 hours, then the sample is taken out of the heating furnace and air-cooled to room temperature.

[0055] Test high temperature tensile properties: The product samples prepared in Example 1 were respectively placed in the heating furnace of the high temperature tensile testing machine, heated to 650°C, 750°C, and 850°C, respectively, and kept warm for 10 minutes before applying force to break the samples, and the yield strength was measured. The samples were compared with those subjected to only the solution heat treatment in step S2. The results are shown in Table 1 below. Figure 1 The δ phase precipitated from the grain boundary of GH625 plate during aging treatment Figure 1 Question 1 also further illustrates that Nb and Ni form a δ phase, which precipitates at the grain boundaries to strengthen the material and improve its high temperature yield strength.

[0056] Table 1 GH625 sheet yield strength (650℃ aging)

[0057]

[0058] It can be seen that the yield strength of the sample that has only been subjected to solution treatment is much lower than that of the sample that has undergone the specially designed solution + aging heat treatment of the present invention, and the performance of the sample that has been heat treated by the present invention is completely beyond the standard.

[0059] Embodiment 2:

[0060] This embodiment provides a GH625 alloy and a heat treatment method and application thereof. The GH625 alloy includes the following components:

[0061] C: 0.047%, Mn: 0.010%, Si: 0.040%, S: 0.0010%, P: 0.0030%, Nb+Ta: 3.50%, Cr: 22.00%, Al: 0.22%, Ti: 0.18%, Co: 0.045%, Mo: 9.00%, Fe: 0.15%, Cu: 0.0090%, the remainder is Ni and other inevitable impurities.

[0062] The application includes applying the GH625 alloy to equipment manufacturing in aviation, chemical industry, nuclear power, and oil fields.

[0063] The heat treatment method of the GH625 alloy comprises:

[0064] S1: Take the alloy raw material to be heat treated, sample on the plate, process the high temperature tensile specimen, and obtain the tensile specimen;

[0065] S2: Solution heat treatment: Place the processed sample in step S1 into a chamber-type electric heating furnace, heat it to 1130°C, and keep it at this temperature for 15 minutes. Then take the sample out of the heating furnace and air cool it to room temperature.

[0066] S3: Aging heat treatment: The sample after the solution treatment is put back into the chamber electric heating furnace, heated to 600°C, kept warm for 20 hours, then taken out of the heating furnace and air-cooled to room temperature.

[0067] Embodiment 3:

[0068] This embodiment provides a GH625 alloy and a heat treatment method and application thereof. The GH625 alloy includes the following components:

[0069] C: 0.050%, Mn: 0.015%, Si: 0.045%, S: 0.0020%, P: 0.0040%, Nb+Ta: 3.70%, Cr: 22.50%, Al: 0.25%, Ti: 0.22%, Co: 0.050%, Mo: 9.10%, Fe: 0.20%, Cu: 0,0100%, the balance is Ni and other inevitable impurities.

[0070] The application includes applying the GH625 alloy to equipment manufacturing in aviation, chemical industry, nuclear power, and oil fields.

[0071] The heat treatment method of the GH625 alloy comprises:

[0072] S1: Take the alloy raw material to be heat treated, sample on the plate, process the high temperature tensile specimen, and obtain the tensile specimen;

[0073] S2: Solution heat treatment: Place the sample processed in step S1 into a chamber-type electric heating furnace, heat it to 1150°C, and keep it at this temperature for 25 minutes. Then take the sample out of the heating furnace and air cool it to room temperature.

[0074] S3: Aging heat treatment: The sample after the solution treatment is put back into the chamber electric heating furnace, heated to 660°C, and kept at this temperature for 26 hours. Then the sample is taken out of the heating furnace and air-cooled to room temperature.

[0075] Embodiment 4:

[0076] The alloy composition of Example 4 is the same as that of Example 1, except that the temperature of the aging heat treatment is different, specifically including:

[0077] The heat treatment method of the GH625 alloy comprises:

[0078] S1: Take the alloy raw material to be heat treated, sample on the plate, process the high temperature tensile specimen, and obtain the tensile specimen;

[0079] S2: Solution heat treatment: Place the sample processed in step S1 into a chamber-type electric heating furnace, heat it to 1140°C and keep it warm for 20 minutes, then take the sample out of the heating furnace and air cool it to room temperature;

[0080] S3: Aging heat treatment: The sample after the solution treatment is put back into the chamber electric heating furnace, heated to 620℃ for 24 hours, then the sample is taken out of the heating furnace and air-cooled to room temperature.

[0081] Embodiment 5:

[0082] The alloy composition of Example 5 is the same as that of Example 1, except that the temperature of the aging heat treatment is different, specifically including:

[0083] The heat treatment method of the GH625 alloy comprises:

[0084] S1: Take the alloy raw material to be heat treated, sample on the plate, process the high temperature tensile specimen, and obtain the tensile specimen;

[0085] S2: Solution heat treatment: Place the sample processed in step S1 into a chamber-type electric heating furnace, heat it to 1140°C and keep it warm for 20 minutes, then take the sample out of the heating furnace and air cool it to room temperature;

[0086] S3: Aging heat treatment: The sample after the solution treatment is put back into the chamber electric heating furnace, heated to 600°C for 24 hours, then the sample is taken out of the heating furnace and air-cooled to room temperature.

[0087] The samples that were solution treated at 1120° C. in Example 4 and Example 5 were subjected to aging treatment at 620° C. and 700° C. for 24 hours, respectively. The yield strengths measured are shown in Tables 2 and 3 below.

[0088] Table 2 GH625 sheet yield strength (620℃ aging)

[0089]

[0090] Table 3 GH625 sheet yield strength (700℃ aging)

[0091]

[0092] Compared with the sample of Example 1 in Table 1, although the yield strength of Examples 4 and 5 is lower than that of Example 1, good yield strength is obtained, which solves the problems existing in the background technology. This further proves that by controlling the temperature range and time of heat treatment within the range of the heat treatment method of the present invention, the high temperature yield performance of GH625 alloy can be achieved, solving the problems in the prior art.

[0093] Through the above embodiments, it is further proved that the present invention provides a heat treatment method for improving the high temperature yield strength of GH625 hot-rolled plate, which combines the dual processes of solution heat treatment and aging heat treatment, and significantly improves the mechanical properties of GH625 alloy at high temperature. Its technical principle is to first perform solution heat treatment in the range of 1100-1200°C to improve the matrix strength of the alloy, and then perform aging heat treatment in the range of 600-700°C to promote the precipitation of the δ phase inside the alloy, thereby achieving a strengthening effect. This method effectively solves the problem of insufficient high temperature yield strength faced by traditional heat treatment processes, ensuring that the GH625 alloy can meet the strict requirements of aviation, chemical and nuclear power industries for material properties.

[0094] By optimizing the heat treatment process parameters, including the holding temperature and time, the present invention achieves uniform precipitation of the strengthening phase in the alloy, thereby improving the high-temperature yield strength. This synergistic effect not only improves the tensile strength of the GH625 alloy, but also ensures the reliability and stability of the material under high-temperature environments, providing strong technical support for the wide application of the alloy under harsh conditions such as high temperature and high pressure. At the same time, the present invention further strengthens the interaction between the elements and improves the comprehensive performance of the material through the design and adjustment of the alloy composition, so that it performs well in practical applications.

[0095] In the description of the embodiments of the present application, it should be noted that in the description of the present application, terms such as "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings. This is only for the convenience of description, and does not indicate or imply that the device or component must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present application.

[0096] In the description of the present application, the description with reference to the terms "one embodiment", "some embodiments", "in the present embodiment", "specific example", or "some examples" etc. means that the specific features, mechanisms, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, mechanisms, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0097] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A heat treatment method for GH625 alloy, characterized in that: The following steps are involved: S1: Take the alloy raw material to be heat treated, sample it and prepare it to obtain a tensile specimen; S2: Solution heat treatment: heating the sample obtained in step S1 to 1100-1200° C., keeping the temperature for 15-30 minutes, and cooling; S3: Aging heat treatment: The sample after the solution heat treatment in step S2 is heated to 600-700° C., kept at this temperature for 20-30 hours, and cooled to complete the heat treatment of the GH625 alloy.

2. The heat treatment method of GH625 alloy according to claim 1, characterized in that: In step S2, the conditions of the solution heat treatment are: the sample obtained in step S1 is subjected to a temperature of 1130-1150° C., kept at that temperature for 15-25 minutes, and then cooled.

3. The heat treatment method of GH625 alloy according to claim 2, characterized in that: The conditions of the solution heat treatment are as follows: the sample obtained in step S1 is subjected to a temperature of 1140° C., kept at that temperature for 20 minutes, and then cooled.

4. The heat treatment method of GH625 alloy according to claim 1, characterized in that: The conditions of the aging heat treatment are: heating the sample after the solution heat treatment in step S2 to 640-660° C., keeping the temperature for 22-26 hours, and cooling.

5. The heat treatment method of GH625 alloy according to claim 4, characterized in that: The conditions of the aging heat treatment are: heating the sample after the solution heat treatment in step S2 to 650° C., keeping the temperature for 24 hours, and cooling.

6. The heat treatment method of GH625 alloy according to claim 1, characterized in that: In the steps S2 and S3, the heating device is an electric heating furnace.

7. The heat treatment method of GH625 alloy according to claim 1, characterized in that: In the steps S2 and S3, the cooling method is: air cooling after exiting the furnace.

8. A GH625 alloy, characterized in that: The GH625 alloy is obtained by the heat treatment method according to any one of claims 1 to 7, and the composition of the GH625 alloy includes: C: 0.047-0.050%, Mn: 0.010-0.015%, Si: 0.040-0.045%, S: 0.0010-0.0020%, P: 0.0030-0.0040%, Nb+Ta: 3.50-3.70%, Cr: 22.00-22.50%, Al: 0.22-0.25%, Ti: 0.18-0.22%, Co: 0.045-0.050%, Mo: 9.00-9.10%, Fe: 0.15-0.20%, Cu: 0.0090-0,0100%, and the balance is Ni and other inevitable impurities.

9. The GH625 alloy according to claim 8, characterized in that: In terms of mass ratio, the composition of the GH625 alloy includes: C: 0.049%, Mn: 0.013%, Si: 0.044%, S: 0.0016%, P: 0.0037%, Nb+Ta: 3.68%, Cr: 22.25%, Al: 0.24%, Ti: 0.20%, Co: 0.047%, Mo: 9.04%, Fe: 0.19%, Cu: 0.0098%, and the balance is Ni and other inevitable impurities.

10. An application of the GH625 alloy according to any one of claims 8 to 9, characterized in that: The application includes applying the GH625 alloy to equipment manufacturing in aviation, chemical industry, nuclear power, and oil fields.

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