Dynamic recrystallization test method for steel grade sensitive to deformation due to temperature change and application of dynamic recrystallization test method

Abstract

The invention provides a dynamic recrystallization test method and application of a steel grade sensitive to deformation due to temperature change, and the method comprises the following steps: welding a thermocouple at the middle position of the cylindrical surface of a sample, the interval between the positive electrode and the negative electrode of the thermocouple being 1.0 + / -0.2 mm; a graphite gasket is arranged between the contact surfaces of the clamp and the sample to form a sample-clamp system; the thickness of the graphite gasket is 0.05 to 0.15 mm; placing the sample-clamp system in a vacuum chamber, vacuumizing until the pressure is less than or equal to 1 * 10 <-3 > Pa, and filling inert protective gas until the pressure is 0.1-0.3 MPa; and heating to 900-1150 DEG C at the speed of 5-15 DEG C / s, preserving heat for 30-120 seconds, and monitoring the temperature of the sample in real time through a thermocouple. The test method provided by the invention has good application in dynamic recrystallization behavior tests of high manganese steel and duplex stainless steel. The method is simple and convenient to operate.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal material testing, and in particular relates to a dynamic recrystallization test method for temperature-sensitive deformation-sensitive steel and its application. Background Art

[0002] In the study of high-temperature deformation behavior of metallic materials, dynamic recrystallization (DRX) is a key mechanism that determines the material's hot working properties and microstructural evolution. This is especially true for temperature-sensitive steels such as high-manganese steel and austenitic stainless steel, whose dynamic recrystallization behavior directly affects the material's ultimate mechanical properties and processing design. Dynamic recrystallization is the process by which work hardening is eliminated and the material's plasticity is restored through the nucleation and growth of grains when the material is subjected to high temperature and stress. This plays an important role in improving the material's formability, optimizing the hot working process, and enhancing the material's ultimate performance.

[0003] However, traditional thermal simulation testing machines simulate thermal processing processes through resistance heating and compression deformation. However, when testing deformation-sensitive steels, the results of dynamic recrystallization tests are often inaccurate. Based on this, this application proposes a dynamic recrystallization test method and application for temperature-sensitive deformation-sensitive steels. Summary of the Invention

[0004] The main purpose of the present invention is to provide a dynamic recrystallization test method and application of steel grades that are sensitive to temperature changes and deformation, aiming to solve the technical problem in the prior art that the heating deformation of the sample affects the test results in the dynamic recrystallization test.

[0005] To achieve the above object, the present invention provides a dynamic recrystallization test method for temperature-sensitive deformation-sensitive steel, comprising the following steps:

[0006] A thermocouple is welded in the middle of the cylindrical surface of the sample, and the interval between the positive and negative poles of the thermocouple is 1.0±0.2 mm.

[0007] A graphite gasket is arranged between the contact surface of the fixture and the sample to form a sample-fixture system; wherein the thickness of the graphite gasket is 0.05-0.15mm, and the purity of the graphite is ≥99.9%.

[0008] The sample-fixture system was placed in a vacuum chamber and evacuated to a vacuum of ≤1×10 -3 After reaching Pa, inert protective gas is filled in to a pressure of 0.1-0.3 MPa.

[0009] Then, the sample is heated to a target temperature of 900 to 1150° C. at a rate of 5 to 15° C. / s, kept at that temperature for 30 to 120 seconds, and the temperature of the sample is monitored in real time by a thermocouple.

[0010] According to an embodiment of the present application, the graphite gasket is a flexible graphite composite gasket, and its operating temperature is 200-1200°C.

[0011] Wherein, the graphite gasket works under an inert protective atmosphere, and the inert protective atmosphere is argon or helium.

[0012] The flexible graphite composite gasket comprises, by mass fraction, ≥95% of expanded graphite and 1-3% of an antioxidant dispersed between graphite layers; the antioxidant is one of sodium borate and zirconium phosphate.

[0013] According to the embodiment of the present application, the resistivity of the graphite gasket is 8 to 12 μΩ·m, the compression rebound rate is ≥85%, and the friction coefficient is 0.12 to 0.15.

[0014] According to an embodiment of the present application, the fixture is made of metal material, including at least one of copper and aluminum; the roughness of the contact surface between the sample and the fixture is ≤0.8 μm.

[0015] According to an embodiment of the present application, when the local temperature difference ΔT of the sample is greater than 10° C., axial compression deformation is applied.

[0016] During the compression deformation process, the current density fluctuation is ≤±5%, and the drum shape symmetry (major axis / minor axis ratio) of the sample is ≤1.10.

[0017] The strain rate of compression deformation is 0.1~10s -1 , true strain 0.2~1.0.

[0018] According to an embodiment of the present application, the compression deformation process adopts segmented strain rate control, including:

[0019] The first stage: strain rate is 2 to 5s -1 , the true strain is 0.05~0.15.

[0020] The second stage: strain rate is 0.1~1s -1 , the true strain is 0.15~0.50.

[0021] The interval between the first stage and the second stage is 1 to 3 seconds, and the temperature fluctuation during the interval is ≤±5°C.

[0022] According to an embodiment of the present application, the welding point of the thermocouple is 1.0 to 2.0 mm away from the end face of the sample.

[0023] According to an embodiment of the present application, the sample is a cylindrical sample with a diameter of 8 to 12 mm and a height of 10 to 15 mm.

[0024] According to the embodiment of the present application, the welding thermocouple adopts a pulse laser welding process with a welding energy of 10 to 15 J / mm 2 , solder joint diameter ≤ 0.3mm.

[0025] The present invention also provides an application of the above-mentioned dynamic recrystallization test method for steel grades that are sensitive to temperature changes and deformation in dynamic recrystallization behavior testing of high manganese steel and duplex stainless steel.

[0026] Compared with the prior art, this application has the following beneficial effects:

[0027] The present application provides a dynamic recrystallization test method and application for steel grades that are sensitive to temperature changes and deformation. By welding a thermocouple in the middle of the cylindrical surface of the sample, the internal temperature of the sample can be accurately measured, thereby improving the uniformity and reliability of the temperature measurement. A graphite gasket of suitable thickness is set between the contact surface of the fixture and the sample. Because graphite has good electrical conductivity and flexibility, it is easy to deform when in contact, thereby increasing the friction between the contact surface of the fixture and the sample, improving the contact heat conduction efficiency, and effectively avoiding or reducing the current fluctuation of the sample during the heating process and the impact of the buffer fixture on the sample when static. By placing the sample-fixture system in a vacuum chamber, the surface oxidation of the sample is suppressed and the accuracy of the test is improved. Afterwards, different heating rates are combined to capture the dynamic recrystallization process of the sample to monitor the temperature of the sample. Through the mutual cooperation of the above steps, the sample is kept at a stable temperature during the heating process, and the temperature is balanced at various locations on the sample. Moreover, the method of the present invention is simple and easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0029] Figure 1 This is a flow chart of the dynamic recrystallization test method for temperature-sensitive deformation steel of the present invention;

[0030] Figure 2 The stress-strain curve of the dynamic recrystallization of a temperature-sensitive deformation-sensitive steel obtained by the method of the present invention is shown in FIG.

[0031] Figure 3 This is the stress-strain curve of dynamic recrystallization of deformation-sensitive steels subjected to temperature changes using traditional methods.

[0032] The realization of the objectives, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0033] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0034] Moreover, the technical solutions between the various embodiments of the present invention may be combined with each other, but this must be based on the fact that ordinary technicians in this field can implement them. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0035] To achieve the above object, the present invention provides a dynamic recrystallization test method for temperature-sensitive deformation-sensitive steel, comprising the following steps:

[0036] S1: A thermocouple is welded in the middle of the cylindrical surface of the sample, with the spacing between the positive and negative electrodes of the thermocouple being 1.0±0.2 mm.

[0037] In some embodiments, a thermocouple is welded in the middle of the cylindrical surface of the sample, wherein the sample needs to be polished and wiped in advance. For example, use sandpaper to polish to make the surface smooth and flat. After polishing is completed, wipe the dust and impurities on the surface of the sample to ensure that the surface is clean and oil-free, so as to reduce the contact resistance caused by the surface roughness of the sample to ensure the quality of welding and the heat conduction effect. By welding the thermocouple to the sample in close contact, the internal temperature of the sample can be accurately measured, and the risk of damage caused by mechanical stress during the test can be reduced. And ensure that the welding point is firm and reliable to improve the heat conduction efficiency between the thermocouple and the sample, thereby ensuring the accuracy and stability of the temperature measurement.

[0038] In some embodiments, the spacing between the positive and negative electrodes of the thermocouple is 1.0±0.2 mm, which helps the thermocouple to contact the sample more evenly, thereby improving the uniformity and reliability of temperature measurement and reducing measurement errors.

[0039] In some embodiments, the welding location should be as far away as possible from stress-bearing areas of the specimen and areas that may experience thermal deformation to prevent deformation or stress concentration from affecting the thermocouple's measurement results. Furthermore, the thermocouple should be protected from mechanical damage or chemical corrosion during the welding process. If the thermocouple is damaged, it should be replaced promptly.

[0040] S2: A graphite gasket is arranged between the contact surface of the fixture and the sample to form a sample-fixture system; wherein the graphite gasket has a thickness of 0.05 to 0.15 mm and a purity of the graphite of ≥99.9%.

[0041] In some embodiments, a sample with a thermocouple welded thereto is placed in a fixture, and a graphite gasket is placed between the contact surface of the fixture and the sample. The specific dimensions of the fixture and the sample are not specifically limited. If the selected fixture matches the size and shape of the sample, displacement or loosening due to mismatch between the fixture and the sample can be avoided, resulting in poor heat conduction or damage to the sample. In addition, a tight fit between the contact surface of the sample and the fixture can be ensured. Because the graphite gasket has good thermal conductivity and chemical stability, it can remain stable at high temperatures, preventing the sample from directly contacting the fixture to produce heat conduction or chemical reaction. In addition, graphite can increase the friction between the sample and the fixture to keep the sample from shifting during the test and in closer contact, thereby improving the accuracy of the test results.

[0042] In some specific embodiments, the thickness of the graphite gasket is 0.1 mm.

[0043] In some embodiments, graphite has a layered structure, with layers connected by van der Waals forces, and carbon atoms within the layers connected by covalent bonds. This structure makes graphite appear to have a certain greasy feel on a macro scale, but when there are slight unevenness between the graphite gasket and the contact surface, the layered structure of graphite will increase the complexity of the contact point, thereby generating greater friction during relative motion. In addition, the hardness of the graphite surface is relatively low. When interacting with the contact surface, graphite gaskets with a thickness of 0.05 to 0.15 mm are more likely to deform, thereby increasing the actual contact area with the sample and increasing friction. Graphite also has good electrical conductivity and flexibility, thereby reducing the current fluctuations of the sample during the heating process and the impact of the buffer fixture on the sample when static. The compression resilience of the graphite gasket can absorb micro-displacements between the fixture and the sample to prevent the sample from falling off.

[0044] S3: Place the sample-fixture system in a vacuum chamber and evacuate the chamber to a vacuum of ≤1×10 -3 After the sample reaches 1000 Pa, an inert protective gas is introduced to a pressure of 0.1-0.3 MPa. This step primarily provides an oxygen-free environment to prevent chemical reactions at high temperatures. The inert gas effectively isolates the oxygen in the air and protects the sample surface.

[0045] In some embodiments, the sample-fixture system is placed in a vacuum chamber, ensuring that it is correctly positioned to prevent displacement of the sample-fixture system during vacuuming, and ensuring that the vacuum chamber is well sealed. All valves and openings are closed, and then the vacuum pump is started to evacuate the chamber. The pressure in the vacuum chamber is then reduced to the desired vacuum level of ≤1×10 - 3 Pa, then turn off the vacuum pump, open the valve of the inert gas cylinder, fill the inert gas into the vacuum chamber through the filling pipe, and fill the inert protective gas to a pressure of 0.1~0.3MPa.

[0046] S4: heating the sample to a target temperature of 900-1150° C. at a rate of 5-15° C. / s, maintaining the temperature for 30-120 seconds, and monitoring the temperature of the sample in real time via a thermocouple.

[0047] In some embodiments, heating the sample at a rate of 5-15°C / s ensures uniform temperature distribution and avoids local overheating or overcooling. Holding the sample allows it to fully reach thermal equilibrium at the target temperature, ensuring consistent temperatures within and on the surface, resulting in a uniform heat treatment. After holding the sample, the sample is allowed to cool naturally to ensure a safe and effective cooling process.

[0048] The above-mentioned dynamic recrystallization test method for steel grades that are sensitive to temperature changes and deformation realizes dual-point synchronous monitoring of the temperature field of the sample by welding a thermocouple in the middle position of the cylindrical surface of the sample. A graphite gasket with a suitable thickness is set between the contact surface of the fixture and the sample, thereby increasing the friction between the contact surface of the fixture and the sample, improving the contact heat conduction efficiency, and effectively avoiding or reducing the current fluctuation of the sample during the heating process and the impact of the buffer fixture on the sample in static state. By placing the sample-fixture system in a vacuum chamber, the surface oxidation of the sample is suppressed and the accuracy of the test is improved. Afterwards, different heating rates are used to capture the dynamic recrystallization process of the sample to monitor the temperature of the sample. Through the mutual cooperation of the above steps, the sample maintains a stable temperature during the heating process, and the temperature at various locations on the sample is balanced. Moreover, the method of the present invention is simple and easy to operate.

[0049] In some embodiments, the graphite gasket is a flexible graphite composite gasket, and its operating temperature is 200-1200°C.

[0050] Wherein, the graphite gasket works under an inert protective atmosphere, and the inert protective atmosphere is argon or helium.

[0051] The flexible graphite composite gasket comprises, by mass fraction, ≥95% of expanded graphite and 1-3% of an antioxidant dispersed between graphite layers; the antioxidant is one of sodium borate and zirconium phosphate.

[0052] In some embodiments, under the protection of argon or helium, the oxidation resistance of the graphite gasket is significantly improved, effectively preventing the oxidation of graphite at high temperatures. It can also effectively isolate oxygen in the air and protect the surface of the sample.

[0053] In some embodiments, expanded graphite is the primary component of the graphite gasket, exhibiting excellent flexibility and elasticity, capable of adapting to deformation caused by temperature changes while maintaining good sealing properties. Antioxidants are dispersed between the graphite layers, effectively enhancing the graphite gasket's antioxidant properties and extending its service life. For example, if the antioxidant is sodium borate, it forms a protective film at high temperatures that covers the graphite surface, preventing it from coming into contact with oxygen and thus providing an antioxidant effect. This further enhances the graphite gasket's service life and reliability.

[0054] In some embodiments, the resistivity of the graphite gasket is 8-12 μΩ·m, the compression rebound rate is ≥85%, and the friction coefficient is 0.12-0.15.

[0055] Graphite is a good conductor of electricity with low resistivity. A high compression rebound rate indicates that a graphite gasket can recover at least 85% of its original thickness after pressure is applied. This ensures that the gasket maintains its sealing performance after repeated use and compression, preventing permanent deformation and failure. Regulating the friction coefficient of a graphite gasket provides excellent self-lubricating properties, reducing friction and wear during installation.

[0056] In some embodiments, the fixture is made of metal material, including at least one of copper and aluminum; and the roughness of the contact surface between the sample and the fixture is ≤0.8 μm.

[0057] In some embodiments, the fixture is made of metal, including at least one of copper and aluminum. Ensure that the fixture surface is smooth and free of scratches or defects. Use a high-precision surface roughness meter to ensure that the contact surface between the specimen and the fixture has a roughness of ≤ 0.8 μm. If the roughness does not meet the requirements, polishing or grinding can be used.

[0058] In some embodiments, axial compression deformation is applied when the local temperature difference ΔT of the sample is greater than 10°C.

[0059] During the compression deformation process, the current density fluctuation is ≤±5%, and the drum shape symmetry (major axis / minor axis ratio) of the sample is ≤1.10.

[0060] The strain rate of compression deformation is 0.1~10s -1 , true strain is 0.2~1.0.

[0061] In some embodiments, a thermocouple is used to monitor the temperature distribution of the sample in real time. When the local temperature difference ΔT of the sample is greater than 10°C, axial compression deformation is performed, and the contact gap is compensated by plastic deformation of the graphite gasket. This can avoid excessive thermal stress or thermal deformation of the sample. For example, the sample is placed on a compression testing machine to ensure good contact between the sample and the fixture. -1 Axial compression deformation is applied at a strain rate of 1000 to ensure that the specimen's deformation behavior remains within a controllable range. During the compression process, the specimen's deformation is monitored in real time to ensure that current density fluctuations remain ≤±5%, thereby minimizing the impact of current density fluctuations on specimen deformation. The specimen's drum symmetry (major axis / minor axis ratio) is maintained at ≤1.10 to prevent excessive uneven deformation.

[0062] In some embodiments, the compression deformation process adopts segmented strain rate control, including:

[0063] The first stage: strain rate is 2 to 5s -1 , the true strain is 0.05~0.15.

[0064] The second stage: strain rate is 0.1~1s -1 , the true strain is 0.15~0.50.

[0065] The interval between the first stage and the second stage is 1 to 3 seconds, and the temperature fluctuation during the interval is ≤±5°C.

[0066] In some embodiments, the compression deformation process is controlled by a segmented strain rate, dividing the entire compression deformation process into multiple stages, each with a different strain rate. The deformation behavior of the specimen and the change in current density are observed to ensure uniform deformation of the specimen.

[0067] In some embodiments, the welding point of the thermocouple is 1.0 to 2.0 mm away from the end face of the sample.

[0068] In some embodiments, the welding point of the thermocouple is 1.0 mm away from the end face of the sample to ensure that the temperature measurement can accurately reflect the temperature change at the end of the sample while avoiding measurement errors caused by the welding point being too far away.

[0069] In some embodiments, the sample is a cylindrical sample with a diameter of 8 to 12 mm and a height of 10 to 15 mm.

[0070] In some embodiments, regulating the size and shape of the sample can ensure the accuracy and repeatability of experimental data, providing reliable data support for material research and application.

[0071] In some embodiments, the welding thermocouple is performed using a pulsed laser welding process with a welding energy of 10 to 15 J / mm. 2 , solder joint diameter ≤ 0.3mm.

[0072] In some embodiments, the weld spot diameter is selected based on the welding energy and the thermocouple material. For example, if the thermocouple material is nickel-chromium-nickel-aluminum, the appropriate welding energy should be determined based on the melting point and thermal conductivity of the material to ensure a secure weld without cold joints. The weld spot diameter can ensure the accuracy and quality of the weld. Excessive welding energy and / or weld spot diameter may cause overheating or damage to the thermocouple material, while insufficient welding energy and / or weld spot diameter may result in a weak weld.

[0073] According to the application of the above-mentioned dynamic recrystallization test method for temperature-sensitive deformation steel grades in the dynamic recrystallization behavior test of high manganese steel and duplex stainless steel.

[0074] In some embodiments, the dynamic recrystallization test method of the present invention is used to conduct hot compression experiments on high manganese steel and duplex stainless steel, which significantly improves the test effect of the stress-strain curve.

[0075] For further understanding of the present invention, now illustrate with examples:

[0076] Example 1

[0077] The specimen was made of high-manganese steel, with a diameter of 10 mm and a height of 12 mm. A thermocouple was welded to the center of the cylindrical surface of the specimen. A graphite gasket was placed between the contact surface of the fixture and the specimen, forming a specimen-fixture system. The graphite gasket was 0.1 mm thick and had a purity of ≥99.9%.

[0078] The sample-fixture system was placed in a vacuum chamber and the vacuum was evacuated to 0.6×10 -3 After the sample is heated to 0.15 MPa, an inert protective gas is introduced to the sample to obtain a stress-strain curve. The sample is then heated to a target temperature of 950°C at a rate of 5-15°C / s and kept at that temperature for 60 seconds. The temperature of the sample is monitored in real time by a thermocouple, and a stress-strain curve is obtained.

[0079] Comparative Example 1

[0080] The sample was made of high manganese steel with a diameter of 8 mm and a height of 12 mm. A thermocouple was welded to the center of the cylindrical surface of the sample. Then, the fixture was directly brought into contact with the sample using the traditional method. The sample was then placed in a vacuum chamber and the vacuum was evacuated to 0.6 × 10 -3 After the sample is heated to 0.15 MPa, an inert protective gas is introduced to the sample to obtain a stress-strain curve. The sample is then heated to a target temperature of 1000°C at a rate of 5-15°C / s and kept at that temperature for 60 seconds. The temperature of the sample is monitored in real time by a thermocouple, and a stress-strain curve is obtained.

[0081] in, Figure 1 This is a flow chart of the dynamic recrystallization test method for temperature-sensitive deformation steel of the present invention; Figure 2 The stress-strain curve of the dynamic recrystallization of a temperature-sensitive deformation-sensitive steel obtained by the method of the present invention is shown in FIG. Figure 3 This is the stress-strain curve of dynamic recrystallization of deformation-sensitive steels subjected to temperature changes using traditional methods.

[0082] Therefore, combined Figure 2 and Figure 3 It can be seen that the stress-strain curve obtained by the dynamic recrystallization test method of the present invention shows a good linear relationship. Figure 2 In the stress-strain curve, a relatively flat platform appears, indicating that during the recrystallization process, the stress of the sample material remains relatively stable while the strain continues to increase. This also proves that this method is suitable for dynamic recrystallization tests on steel grades that are sensitive to temperature changes and deformation.

[0083] The present invention can accurately measure the internal temperature of the sample by welding a thermocouple in the middle of the cylindrical surface of the sample, thereby improving the uniformity and reliability of the temperature measurement. A graphite gasket with a suitable thickness is provided between the contact surface of the fixture and the sample, thereby increasing the friction between the contact surface of the fixture and the sample, improving the contact heat conduction efficiency, and effectively avoiding or reducing the current fluctuation of the sample during the heating process and the impact of the buffer fixture on the sample in static state. By placing the sample-fixture system in a vacuum chamber, the surface oxidation of the sample is suppressed and the accuracy of the test is improved. Afterwards, different heating rates are combined to capture the dynamic recrystallization process of the sample to monitor the temperature of the sample. Through the mutual cooperation of the above steps, the sample maintains a stable temperature during the heating process, and the temperature at various locations on the sample is balanced. Moreover, the method of the present invention is simple and easy to operate.

[0084] In summary, the above technical solutions of the present invention are only preferred embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention's description and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A dynamic recrystallization test method for steel grades that are sensitive to temperature changes, characterized in that: The following steps are involved: S1: Weld a thermocouple in the middle of the cylindrical surface of the sample, with the spacing between the positive and negative electrodes of the thermocouple being 1.0 ± 0.2 mm; S2: A graphite gasket is placed between the contact surface of the fixture and the sample to form a sample-fixture system; wherein the graphite gasket has a thickness of 0.05 to 0.15 mm and a purity of graphite of ≥99.9%; S3: placing the sample-fixture system in a vacuum chamber, evacuating the chamber to a pressure of ≤1×10-3Pa, and then filling the chamber with inert protective gas to a pressure of 0.1-0.3MPa; S4: heating the sample to a target temperature of 900-1150° C. at a rate of 5-15° C. / s, maintaining the temperature for 30-120 seconds, and monitoring the temperature of the sample in real time via a thermocouple.

2. The dynamic recrystallization test method for temperature-sensitive deformation steel according to claim 1, characterized in that: The graphite gasket is a flexible graphite composite gasket, and its operating temperature is 200-1200°C; Wherein, the graphite gasket works under an inert protective atmosphere, and the inert protective atmosphere is argon or helium; The flexible graphite composite gasket comprises, by mass fraction, ≥95% of expanded graphite and 1-3% of an antioxidant dispersed between graphite layers; the antioxidant is one of sodium borate and zirconium phosphate.

3. The dynamic recrystallization test method for temperature-sensitive deformation steel according to claim 1, characterized in that: The resistivity of the graphite gasket is 8-12 μΩ·m, the compression rebound rate is ≥85%, and the friction coefficient is 0.12-0.

15.

4. The dynamic recrystallization test method for temperature-sensitive deformation steel according to claim 1, characterized in that: The fixture is made of metal material, including at least one of copper and aluminum; the roughness of the contact surface between the sample and the fixture is ≤0.8 μm.

5. The dynamic recrystallization test method for temperature-sensitive deformation steel according to claim 1, characterized in that: When the local temperature difference ΔT of the sample is greater than 10°C, axial compression deformation is applied; Wherein, during the compression deformation process, the current density fluctuation is ≤±5%, and the drum symmetry (major axis / minor axis ratio) of the sample is ≤1.10; The strain rate of compression deformation is 0.1~10s-1, and the true strain is 0.2~1.

0.

6. The dynamic recrystallization test method for temperature-sensitive deformation steel according to claim 5, characterized in that: The compression deformation process adopts segmented strain rate control, including: The first stage: the strain rate is 2 to 5 s-1, and the true strain is 0.05 to 0.15; The second stage: the strain rate is 0.1 to 1s-1, and the true strain is 0.15 to 0.50; The interval between the first stage and the second stage is 1 to 3 seconds, and the temperature fluctuation during the interval is ≤±5°C.

7. The dynamic recrystallization test method for temperature-sensitive deformation steel according to claim 1, characterized in that: The welding point of the thermocouple is 1.0 to 2.0 mm away from the end face of the sample.

8. The dynamic recrystallization test method for temperature-sensitive deformation steel according to claim 1, characterized in that: The sample is a cylindrical sample with a diameter of 8 to 12 mm and a height of 10 to 15 mm.

9. The dynamic recrystallization test method for temperature-sensitive deformation steel according to claim 1, characterized in that: The welding thermocouple adopts pulse laser welding technology, and the welding energy is 10-15J / mm 2 , solder joint diameter ≤ 0.3mm.

10. Application of the dynamic recrystallization test method for temperature-sensitive deformation steel according to any one of claims 1 to 9 in dynamic recrystallization behavior testing of high manganese steel and duplex stainless steel.

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