A heat treatment method for high-strength, light-weight, wear-resistant high-manganese steel castings

Abstract

The present invention relates to a heat treatment method for a high-strength, tough, lightweight, wear-resistant high-manganese steel casting, and the steps are as follows: pretreatment: coating an anti-oxidation protective coating on the surface of the high-manganese steel casting; water toughening treatment: heating the high-manganese steel casting to the water toughening temperature at a preset speed, keeping the temperature and then water quenching; cryogenic treatment: cooling the high-manganese steel casting after water toughening to the cryogenic treatment temperature and keeping the temperature; aging treatment: heating the high-manganese steel casting after cryogenic treatment to the aging temperature and keeping the temperature, keeping the temperature, and then air cooling to room temperature, and the interval between cryogenic treatment and aging treatment is not more than 1h; shot peening treatment: shot peening treatment is performed on the surface of the high-manganese steel casting after aging treatment. The present invention utilizes a combination of water toughening, cryogenic treatment and aging treatment to obtain a single austenite structure, obtain an effective dispersed nano-scale carbide structure, and effectively improve the grain refinement and solid solution strengthening effect of the high-strength, tough, lightweight high-manganese steel.

Description

Technical Field

[0001] The invention relates to the technical field of heat treatment of light high manganese steel, and more particularly to a heat treatment method for a high-strength, light, wear-resistant high manganese steel casting. Background Art

[0002] High manganese steel has been used as a wear-resistant material for nearly a hundred years. With the intensification of energy problems and the deterioration of service conditions, a new type of Fe-Mn-Al-C lightweight high manganese steel was developed in the 1960s. Subsequently, people have conducted extensive research on the casting process, forging process, alloying and heat treatment of Fe-Mn-Al-C lightweight high manganese steel. The heat treatment of Fe-Mn-Al-C lightweight high manganese steel is also called water toughening treatment. Water toughening treatment is to heat the lightweight high manganese steel to a certain temperature (generally 800-1100℃), keep it warm for a period of time, and quench it with water to room temperature to obtain a single austenite structure. Aging treatment is to continue to heat the sample after water toughening treatment in a heat treatment furnace to a certain temperature and keep it warm for a certain period of time. However, after water toughening and aging treatment, the carbides of lightweight high manganese steel are coarse and unevenly distributed, and it is difficult to control the precipitation of carbides. The high manganese steel finally obtained cannot meet the actual production requirements of modern equipment. Therefore, it is necessary to study the heat treatment process based on the new lightweight high manganese steel.

[0003] After searching, the Chinese patent application number is: 201910839718.2, and the name of the invention is: A heat treatment method for improving the mechanical properties of Fe-Mn-Al-C TRIP steel. The application discloses a heat treatment method for improving the mechanical properties of Fe-Mn-Al-C TRIP steel, wherein the smelted steel ingot is heated to 1200-1230°C, kept warm for 2-2.5 hours, and then forged into a steel billet; then, the billet is kept warm at 1200-1250°C for 2-2.5 hours and then rolled, the starting rolling temperature is 1150-1200°C, and the final rolling temperature is 850-900°C; then, it is quenched at 650-750°C, kept warm for 1-1.5 hours, and water quenched to room temperature; tempered at 200-220°C and kept warm for 1-1.5 hours, and then air-cooled to room temperature. This application overcomes the shortcomings of the prior art of high heat treatment cost and complex process of TRIP steel. It adopts quenching + tempering process. Compared with critical heat treatment, bainite isothermal transformation and austenite reverse transformation, this method is simple to operate and has better performance than conventional hot-rolled TRIP steel. However, this application still has room for further optimization in terms of operational convenience.

[0004] Chinese patent application number: CN201811512971.9 (A process for preparing an automobile inspection fixture that is not easily damaged). This invention patent provides a process for preparing a high manganese steel automobile inspection fixture. Step six adopts cryogenic treatment, and liquid nitrogen gas method is used to spray liquid nitrogen onto the mold through a nozzle. The liquid nitrogen acts on the metal surface for 20 to 30 seconds. The purpose is to eliminate the unbalanced stress on the metal surface caused by steps three, four, and five, and improve the performance of the mold. Many researchers have done a lot of work in this regard, improved the relevant processes of heat treatment, and gained more heat treatment experience, but they all face the dilemma of poor comprehensive performance, low initial yield or only high strength, very low toughness, long heat treatment process flow, complex process technology (forging, rolling, quenching, tempering), and low production efficiency.

[0005] In summary, how to regulate the distribution and size of carbides in the structure of lightweight high manganese steel castings after an effective heat treatment method, so as to obtain high-strength, tough, lightweight, wear-resistant high manganese steel with good comprehensive performance, reduce production costs and improve production efficiency is a problem that needs to be urgently solved by technical personnel in this field. Summary of the invention

[0006] Purpose of the invention:

[0007] In view of the problem that the above-mentioned prior art has poor comprehensive performance of light high manganese steel due to the distribution and size of carbides in the structure of light high manganese steel castings, the purpose of the present invention is to provide a heat treatment method for high-strength and tough light high manganese steel castings used in the wear-resistant field, which uses a combination of water toughening, deep cooling and aging treatment to obtain a single austenite structure, obtain an effective dispersed nano-scale carbide structure, and effectively improve the grain refinement and solid solution strengthening effect of high-strength and tough light high manganese steel. In order to achieve the above purpose, the technical solution provided by the present invention is:

[0008] A heat treatment method for a high-strength, light-weight, wear-resistant high-manganese steel casting comprises the following steps:

[0009] S1. Pretreatment: Anti-oxidation protective coating is applied on the surface of high manganese steel castings;

[0010] S2. Water toughening treatment: heat the high manganese steel casting at a preset speed to the water toughening temperature, which is 1040-1200℃, keep it warm for 30min to 90min, and then water quench it;

[0011] S3. Cryogenic treatment: Cool the high manganese steel casting after water toughening to the cryogenic treatment temperature and keep it warm for 1h to 48h;

[0012] S4, aging treatment: heat the high manganese steel casting after deep freezing treatment to the aging temperature and keep it warm for 30min to 240min, then air cool it to room temperature, and the interval between deep freezing and aging treatment shall not exceed 1h;

[0013] S5. Shot peening: The surface of high manganese steel castings after aging treatment is shot peened.

[0014] Preferably, the oxidation protective coating is Al2O3-SiO2-Na2O, and the components by mass percentage are SiO2: 65-70%, Al2O3: 10-20%, ZrO2: 3-5%, B2O3: 1-5%, MgO: 2-7%, CaO: 2-4%, Na2O: 4-9%, and Others: 3-10%.

[0015] Preferably, the oxidation protection coating is a high-temperature anti-oxidation coating prepared by spraying on the surface of high-strength, tough, lightweight, wear-resistant high-manganese steel.

[0016] Preferably, the preset speed in S2 is not less than 100°C / h.

[0017] Preferably, the water toughening temperature of the workpiece in S2 is 1050°C and the holding time is 1h.

[0018] Preferably, the cryogenic treatment temperature in S3 is -130°C to -196°C.

[0019] Preferably, in S3, the workpiece is deep-cooled to -196°C, kept warm for 12 hours, and quenched in water to room temperature, with the water temperature not higher than 20°C.

[0020] Preferably, the aging temperature in S4 is 450-650°C.

[0021] Preferably, in S4, the aging temperature of the workpiece is 550° C., the holding time is 1 hour, and then the workpiece is air-cooled to room temperature.

[0022] Preferably, the shot peening is performed on the surface of the sample using a pneumatic shot peening machine; the main parameters of the shot peening are: air pressure 0.18-0.5 MPa, shot material is cast steel 30, shot diameter is 0.2 mm, spray time is 2-60 min, and spray angle is 85°.

[0023] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0024] (1) The present invention can obtain Fe-Mn-Al-C lightweight high manganese steel with a density range of 6.6 g / cm 3 ~7.0g / cm 3 , which is 10% to 15% lower than traditional steel. It can obtain high-strength, light-weight, wear-resistant high-manganese steel with a tensile strength of 700 to 850 MPa and an elongation of 45 to 55%. It has better performance than samples treated by conventional heat treatment processes and is expected to become an effective process for obtaining high-strength, light-weight, wear-resistant high-manganese steel.

[0025] (2) The heat treatment method of a high-strength, high-toughness, light-weight, wear-resistant high-manganese steel casting of the present invention significantly increases the content of carbides in the treated steel body and significantly makes the distribution uniform. The uniform distribution of nano-carbides can significantly improve the comprehensive performance of Fe-Mn-Al-C series light-weight high-manganese steel, thereby extending the service life of the material and having a good application prospect.

[0026] (3) Compared with the conventional heat treatment method of Fe-Mn-Al-C steel, the heat treatment method of the present invention has a strength-ductility product of 33Gpa% to 46Gpa% for high-strength, high-toughness, light-weight, wear-resistant high-manganese steel. The steel body after treatment has a strength-ductility product of 33Gpa% to 46Gpa%, which is much higher than the steel requirement of 30Gpa% for automobiles, and has better comprehensive performance.

[0027] (4) The coating of the present invention can improve the surface quality of lightweight high manganese steel and prevent high-temperature decarburization and oxidation.

[0028] (5) Compared with heat treatment after rolling, the heat treatment method of the high-strength, high-toughness, light-weight, wear-resistant high-manganese steel casting of the present invention has a simple operation process and is easy to implement; the whole process takes less time, and the solid solution and aging treatment are both short-term treatments; thereby reducing production costs, without damaging samples, and causing no pollution to the environment, and is a green treatment process.

[0029] (6) The heat treatment method of the present invention for high-strength, high-toughness, light-weight, wear-resistant high-manganese steel can significantly improve the strength while maintaining a high plasticity compared to conventional heat treatment (water toughening plus aging), thereby obtaining high-strength, high-toughness, light-weight, wear-resistant high-manganese steel castings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Figure 2 is a metallographic microstructure diagram of the lightweight wear-resistant high manganese steel of the present invention, wherein a) is the metallographic microstructure of the high-strength and tough lightweight high manganese steel in the cast state; b) is the metallographic microstructure of the high-strength and tough lightweight high manganese steel after heat treatment but without deep cooling of the present invention; Figure c) is the metallographic microstructure of the high-strength and tough lightweight high manganese steel after heat treatment and deep cooling of the present invention.

[0031] Figure 2 The stress-strain curve of the lightweight wear-resistant high manganese steel of the present invention includes stress-strain curves of no cryogenic treatment (marked as conventional water toughening treatment in the figure), cryogenic treatment for 1 hour, cryogenic treatment for 12 hours, and cryogenic treatment for 48 hours. DETAILED DESCRIPTION

[0032] The present invention will be further described below in conjunction with the embodiments.

[0033] Embodiment 1

[0034] A heat treatment method for a high-strength, light-weight, wear-resistant high-manganese steel casting comprises the following steps:

[0035] S1. Pretreatment: Anti-oxidation protective coating is applied on the surface of high-strength, light-weight, wear-resistant high-manganese steel castings;

[0036] The high-strength, tough, lightweight, wear-resistant high manganese steel described in the present application is a Fe-Mn-Al-C system or a Fe-Mn-C system lightweight high manganese steel. In this embodiment, the Fe-Mn-Al-C system is used as an example for illustration. The composition of the lightweight high manganese steel is Mn22-32% by mass; Al7-11%; C1.0-1.5%, and the rest is Fe and unavoidable impurities.

[0037] Mn: It is the main alloying element of high manganese steel and also the main element for stabilizing austenite. Mn is easily dissolved in austenite, can expand the γ phase region, and promote the formation of a single austenite structure. When the carbon content remains unchanged, as the manganese content increases, the high manganese steel structure will first change from pearlite to martensite, and then further transform into austenite. If the manganese content is reduced, the stability of austenite may be reduced, the toughness will be reduced, but the work hardening performance can be enhanced. When the manganese content is too high, the thermal conductivity of the steel is reduced and it is easy to form a transgranular structure. Manganese can strongly promote the growth of austenite grains, make the austenite grains coarser, and easily produce columnar crystals. It also increases the condensation shrinkage of high manganese steel and forms thermal cracks.

[0038] C: It can promote the formation of austenite structure. If the C content is too low, it will be difficult to form a single-phase austenite structure and the work hardening ability will be insufficient. C will dissolve into the austenite matrix and play a role in solid solution strengthening, which can increase the hardness and strength of high manganese steel and reduce toughness and plasticity.

[0039] Al: The main purpose of adding is to reduce density. Only more than 7% Al can reduce the density of high manganese steel to 7g / cm 3 Below, the purpose of lightweight is achieved. However, too high Al content will reduce the γ phase area. And Al is a ferrite stabilizing element, which promotes the formation of ferrite structure and reduces the work hardening ability of high manganese steel; it reduces the activity of carbon, increases the solubility of carbon in austenite, and reduces the precipitation of carbides.

[0040] The oxidation protection coating is a high-temperature oxidation protection coating prepared on the surface of high-strength, tough, lightweight, wear-resistant high manganese steel by spraying. The oxidation protection coating is Al2O3-SiO2-Na2O, and its composition is SiO2 (65wt% to 70wt%), Al2O3 (10wt% to 20wt%), ZrO2 (3wt% to 5wt%), B2O3 (1wt% to 5wt%), MgO (2wt% to 7wt%), CaO (2wt% to 4wt%), Na2O (4wt% to 9wt%), and Other (3wt% to 10wt%). This coating adopts a slurry spraying method, with widely distributed natural minerals and metallurgical solid waste as the main raw materials, to produce a heat treatment coating that can be sprayed on the surface of steel billets at room temperature to 700°C. This coating can improve the surface quality of lightweight high manganese steel and prevent high-temperature decarburization and oxidation. When cooled from high temperature to room temperature, the coating on the surface of the coated sample automatically peels off, and there is almost no coating residue; while the surface of the blank sample is attached with a layer of oxide that is extremely difficult to remove, and it will decarburize at high temperature to form a carbon layer. The coating process of other coatings is complicated and the raw material cost is high, such as: solution precursor-plasma spraying method, first using chemical reagents to prepare the precursor, and then using plasma spraying equipment to prepare the coating; and the preparation of spinel coating also requires the use of glycine-nitrate method to first burn and synthesize spinel raw materials; LSM and LSCF coatings use rare earth elements and Co, Sr, etc. as raw materials, and are deposited and coated in an aerosol box. Without anti-oxidation treatment, the number, size, and distribution of carbides in steel cannot be controlled, and its strengthening effect cannot be predicted, and the quality of the finished steel cannot be guaranteed, so the yield rate decreases and the production efficiency decreases, so oxidation protection coating is very necessary.

[0041] S2, water toughening treatment: heat the sample steel at a preset speed to the water toughening temperature, the water toughening temperature is 1050℃, keep it warm for 1h and then water quench it in water with a temperature not higher than 20℃. The water temperature after quenching is not higher than 50℃;

[0042] The preset speed is not less than 100℃ / h. During the heating process, brittle carbides gradually dissolve into austenite. A higher heating rate provides a greater superheat for the solid solution of carbides, so that the carbides are completely dissolved, thereby strengthening the cryogenic treatment, obtaining better results, and improving the strength and plasticity of lightweight high manganese steel.

[0043] S3, cryogenic treatment: cool the water-toughened sample to a cryogenic treatment temperature between -130℃ and -196℃, and keep it warm for 1 hour; preferably, the workpiece cryogenic temperature is -196℃. The sample steel obtained in S2 is immersed in nitrogen at -130℃ to -196℃, and kept warm for 1 to 48 hours; it is generally believed that the effect of cryogenic treatment on the workpiece structure and performance is greater than that of shallow cryogenic treatment, and the lower the temperature, the better the effect of cryogenic treatment, so -196℃ is used for cryogenic treatment. The precipitation of fine carbides takes time. If the cryogenic treatment time is too long, it will lead to a waste of resources and even a decrease in material performance; if the cryogenic time is insufficient, the full effect of cryogenic treatment cannot be exerted.

[0044] S4. Aging treatment: Heat the sample after cryogenic treatment to 550℃ and keep it warm for 1h, then air-cool it to room temperature (25℃), and the interval between cryogenic treatment and aging treatment should not be more than 1h. This is to retain the dislocations formed during the cryogenic process and ensure the treatment effect of the steel after aging.

[0045] S5. Shot peening: The surface of high manganese steel castings after aging treatment is shot peened.

[0046] The shot peening treatment uses a pneumatic shot peening machine to perform shot peening treatment on the surface of the sample; the main parameters of the shot peening are: air pressure 0.18-0.5MPa, shot material is cast steel 30, shot diameter 0.2mm, spray time 2-60min, spray angle 85°. This technology can be used to prepare a surface layer with nanocrystalline structure characteristics on the surface of light high manganese steel, thereby improving the surface hardness and extending the service life of light high manganese steel.

[0047] Figure 1 The metallographic microstructure diagrams of lightweight wear-resistant high manganese steel before and after heat treatment, wherein Figure a) is the metallographic microstructure of high-strength and tough lightweight high manganese steel in the cast state; b) is the metallographic microstructure of high-strength and tough lightweight high manganese steel after heat treatment but without deep cooling of the present invention; Figure c) is the metallographic microstructure of high-strength and tough lightweight high manganese steel after heat treatment and deep cooling of the present invention. From Figure a), it can be observed that the structure is a single austenite structure, and no carbides are observed; from Figure b), it can be observed that the structure is a single austenite structure, carbides are precipitated, but the number of carbides is small, and they are agglomerated in one piece, with a large size and uneven distribution; from Figure c), it can be observed that the structure is also a single austenite structure, but many fine carbides are precipitated, and the grain size is obviously smaller than the cast state. Fine dispersed carbides are obtained through the process treatment of the present invention, and these fine dispersed carbides will inhibit the growth of grains, obtain fine austenite structures, and ultimately improve the strength and toughness of the steel in a coordinated manner.

[0048] Figure 2The stress-strain curves of lightweight wear-resistant high manganese steel before and after heat treatment. The figure contains stress-strain curves without cryogenic treatment (marked as conventional water toughening treatment in the figure), cryogenic 1h, cryogenic 12h, and cryogenic 48h. It can be observed from the figure that the strength of the sample after cryogenic treatment is improved, but the plasticity is slightly reduced. When cryogenically treated for 48h, the strength can be improved but the toughness is not reduced. This is attributed to the beneficial effect of cryogenic treatment on the distribution of carbide morphology and size. Nano-scale finely dispersed carbides greatly improve the comprehensive properties of lightweight high manganese steel.

[0049] According to the national standard GB / T 228.1-2010, a quasi-static uniaxial tensile test was carried out at room temperature on an ETM105D electronic universal testing machine with a crosshead speed of 2.5 mm / min. Each set of tensile data is the average of at least 3 tensile results. Finally, the density range of Fe-Mn-Al-C lightweight high manganese steel is 6.6 g / cm 3 ~7.0g / cm 3 , 10% to 15% lower than conventional steel. The tensile strength is 750-850MPa, the elongation is 45%-55%, and the strength-plasticity product is 33Gpa% to 46Gpa%. The strength-plasticity product is a comprehensive performance indicator that characterizes the strength and toughness level of metal materials - static toughness (which can be approximately characterized by the "strength-plasticity product"). It is the product of the tensile strength of steel and the elongation after fracture (i.e., elongation). Its value is approximately equal to the area enclosed by the tensile curve of the steel, which represents the energy absorbed by the steel during the tensile test or the work done by the external force when the specimen is broken. The calculation formula is U T =σ b ×δ.

[0050] The steel used in this embodiment is Fe-25Mn-7Al-C, and the heat treatment process is water toughening temperature 1050℃, insulation for 1h; deep cooling for 1h, aging at 550℃, insulation for 1h; conventional heat treatment process 1# steel is Fe-32Mn-9Al-1.4C, and the heat treatment process is water toughening temperature 1050℃, insulation for 1.5h; aging at 500℃, insulation for 3h; conventional heat treatment process 2# steel is Fe-32Mn-9Al-1.4C, and the heat treatment process is water toughening temperature 1050℃, insulation for 1.5h; aging at 600℃, insulation for 3h. Conventional heat treatment process 3# steel is Fe-32Mn-9Al-1.4C, and the heat treatment process is water toughening temperature 1050℃, insulation for 1.5h; aging at 500℃, insulation for 2h. Conventional heat treatment process 4# steel is Fe-32Mn-9Al-1.4C, heat treatment process is water toughening temperature 1050℃, heat preservation 1.5h; aging 600℃, heat preservation 4h. The mechanical properties of light high manganese steel in different states are shown in Table 1.

[0051] Table 1 Mechanical properties of lightweight high manganese steel in different states

[0052]

[0053]

[0054] As can be seen from Table 1, the present invention can effectively improve the mechanical properties of Fe-Mn-Al-C series lightweight high manganese steel, whether it is yield, tensile strength or elongation, all of which are greatly improved. The heat treatment process of the present invention improves the tensile strength by 28.7% and the elongation by 1000% compared with conventional heat treatment 2#. Compared with conventional heat treatment 1#, both tensile strength and yield are reduced, but the elongation of No. 1 is only 8.4%. As can be seen from Table 1, the strength-plasticity product of the present invention is better than that of other conventional heat-treated samples. The heat treatment process of this article can significantly improve the strength while still maintaining a high plasticity to obtain high-strength and lightweight high manganese steel castings.

[0055] Embodiment 2

[0056] The steel used in this embodiment is Fe-25Mn-7Al-C, and the heat treatment process is water toughening temperature 1050℃, insulation for 1h; deep cooling for 12h, aging at 550℃, insulation for 1h; the steel used in the embodiment is Fe-25Mn-7Al-C, which has not been deep-cooled. The water toughening temperature is 1050℃, insulation for 1h; deep cooling for 0h; aging at 550℃, insulation for 1h, and the interval between deep cooling and aging treatment does not exceed 1h. The best yield strength obtained in this embodiment is 667Mpa. The tensile strength is 798Mpa and the elongation is 45.5%. The conventional heat treatment process 1# steel is Fe-32Mn-9Al-1.4C, and the heat treatment process is water toughening temperature 1050℃, insulation for 1.5h; aging at 450℃, insulation for 1h. Conventional heat treatment process 2# steel is Fe-32Mn-9Al-1.4C, and the heat treatment process is water toughening temperature 1050℃, heat preservation 1.5h; aging 450℃, heat preservation 4h. From Table 2, it can be seen that the strength and plasticity product of this patent is better than other conventional heat treatment samples. The heat treatment process in this paper can significantly improve the strength while still maintaining a high plasticity, and obtain high-strength and light-weight high-manganese steel castings.

[0057] Table 2 Mechanical properties of lightweight high manganese steel in different states

[0058]

[0059] Embodiment 3

[0060] Water toughening temperature 1050℃, keep warm for 1h; deep cooling 48h; aging 550℃, keep warm for 1h, the interval between deep cooling and aging treatment is no more than 1h, and this embodiment obtains the best elongation of 55%. Yield strength 580Mpa, tensile strength 779Mpa, elongation 55.0%. Yield strength 580Mpa, tensile strength 779Mpa, elongation 55.0%. Conventional heat treatment process 1# steel is Fe-32Mn-9Al-1.4C, heat treatment process is water toughening temperature 1050℃, keep warm for 1.5h; aging 500℃, keep warm for 3h. Conventional heat treatment process 2# steel is Fe-32Mn-9Al-1.4C, heat treatment process is water toughening temperature 1050℃, keep warm for 1.5h; aging 500℃, keep warm for 4h. It can be seen from Table 3 that the strength and plasticity product of this patent is better than other conventional heat-treated samples. The heat treatment process in this paper can significantly improve the strength while maintaining a high plasticity to obtain high-strength, tough, lightweight high-manganese steel castings.

[0061] Table 3 Mechanical properties of lightweight high manganese steel in different states

[0062]

[0063]

[0064] Embodiment 4

[0065] Water toughening temperature 950℃, keep warm for 1.5h; deep cooling for 1h; aging at 450℃, keep warm for 1.5h, the interval between deep cooling and aging treatment shall not exceed 1h. Yield strength 642Mpa, tensile strength 789Mpa, elongation 45.0%.

Claims

1. A heat treatment method for high-strength, light-weight, wear-resistant high-manganese steel castings, characterized in that: The following steps are involved: S1. Pretreatment: The surface of the high manganese steel casting is coated with an anti-oxidation protective coating to prevent high-temperature decarburization and oxidation; the high manganese steel casting is a Fe-Mn-Al-C series or Fe-Mn-C series lightweight high manganese steel; S2. Water toughening treatment: heat the high manganese steel casting at a preset speed to the water toughening temperature, which is 1040-1200℃, keep it warm for 30min to 90min, and then water quench it; S3. Cryogenic treatment: Cool the high manganese steel casting after water toughening to the cryogenic treatment temperature, the cryogenic treatment temperature is -130℃~-196℃, keep warm for 1h~48h, and obtain fine dispersed carbides; S4, aging treatment: heat the high manganese steel casting after deep cooling treatment to the aging temperature, the aging temperature is 450-650℃, the insulation time is 30min~240min, and then air-cool to room temperature, and the interval between deep cooling and aging treatment is no more than 1h; S5. Shot peening: The surface of high manganese steel castings after aging treatment is shot peened.

2. The heat treatment method of a high-strength, light-weight, wear-resistant high-manganese steel casting according to claim 1, characterized in that: The oxidation protection coating is Al2O3-SiO2-Na2O, and the components are SiO2: 65-70%, Al2O3: 10-20%, ZrO2: 3-5%, B2O3: 1-5%, MgO: 2-7%, CaO: 2-4%, Na2O: 4-9%, and others: 3-10% by mass percentage.

3. The heat treatment method of a high-strength, light-weight, wear-resistant high-manganese steel casting according to claim 1, characterized in that: The oxidation protection coating is a high-temperature oxidation protection coating prepared on the surface of high-strength, tough, lightweight, wear-resistant high-manganese steel by a spraying method.

4. The heat treatment method of a high-strength, light-weight, wear-resistant high-manganese steel casting according to claim 1, characterized in that: The preset speed in S2 is not less than 100℃ / h.

5. The heat treatment method of a high-strength, light-weight, wear-resistant high-manganese steel casting according to claim 1, characterized in that: The water toughening temperature of the workpiece in S2 is 1050℃ and the holding time is 1h.

6. The heat treatment method of a high-strength, light-weight, wear-resistant high-manganese steel casting according to claim 1, characterized in that: In S3, the workpiece is deep-cooled to -196°C, kept warm for 12h, and then quenched in water to room temperature with the water temperature not higher than 20°C.

7. The heat treatment method of a high-strength, light-weight, wear-resistant high-manganese steel casting according to claim 1, characterized in that: In S4, the workpiece aging temperature is 550 °C, the holding time is 1 h, and then air-cooled to room temperature.

8. The heat treatment method of a high-strength, light-weight, wear-resistant high-manganese steel casting according to claim 1, characterized in that: The shot peening treatment uses a pneumatic shot peening machine to perform shot peening on the surface of the sample; the main parameters of the shot peening are: air pressure 0.18-0.5MPa, shot material is cast steel 30, shot diameter is 0.2mm, spray time is 2-60min, and spray angle is 85°.

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