A heat treatment process for high-manganese steel with high yield strength, high plasticity and high and low temperature toughness

Abstract

This invention discloses a heat treatment process for high-manganese steel with high yield strength, high plasticity, and high-low temperature toughness, comprising the following steps: hot rolling, cold rolling, warm rolling, and low-temperature annealing of a high-manganese steel billet to obtain high-manganese steel. This invention, through a hot rolling + cold rolling + warm rolling + low-temperature annealing process, obtains a microstructure consisting of a mixture of coarse grains (5 μm) with high local dislocation density and ultrafine grains (200-800 nm) with abundant dynamic recrystallization. Through multiple strengthening mechanisms such as fine grain strengthening and dislocation strengthening, a yield strength of 1100-1350 MPa at -196℃, a tensile strength of 1300-1600 MPa, an elongation of 40%-74%, and an impact toughness of 110-140 J / cm² are achieved. 2 High manganese steel.

Description

Technical Field

[0001] This invention belongs to the technical field of low-temperature steel, specifically relating to a heat treatment process for high-manganese steel with high yield strength, high plasticity and high and low temperature toughness. Background Technology

[0002] The rapid development of marine energy projects such as offshore platforms, oil and gas transport vessels, and pipelines not only requires a large amount of high-strength, high-toughness, and low-temperature steel, but also places higher demands on its performance. Over the past few decades, nickel-based low-temperature steels (0.5-9Ni, wt.%) have gradually replaced more expensive materials such as austenitic stainless steel, Invar alloys, and nickel-chromium alloys due to their superior low-temperature performance. However, my country's nickel resources are relatively scarce and have remained expensive, leading to heavy reliance on imports and persistently high costs for nickel steel. In recent years, researchers have been developing high-manganese austenitic low-temperature steels by replacing nickel with the austenitic stabilizing element manganese. This technology reduces costs while exhibiting higher tensile strength, elongation, and work hardening rate, demonstrating considerable development potential.

[0003] However, there are very few strengthening methods for fully austenitic high-manganese steel, resulting in a low room temperature yield strength of only 200-400 MPa, which severely limits the application of this type of material in marine engineering. Although dispersion strengthening and deformation strengthening can significantly increase its yield strength to 400-600 MPa, this leads to a significant reduction in the plasticity and toughness of the steel. This not only causes the problem of "strength-plasticity inversion" but may also lead to the "ductile-brittle transition" phenomenon, which is rare in face-centered cubic steel, thus impairing its low-temperature performance. Summary of the Invention

[0004] This invention provides a heat treatment process for high-manganese steel with high yield strength, high plasticity, and high and low temperature toughness, which can solve the problems of low yield strength and insufficient low temperature toughness of high-manganese steel for low temperature applications in the prior art.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] In one aspect, this invention provides a heat treatment process for high-manganese steel with high yield strength, high plasticity, and high and low temperature toughness, comprising the following steps:

[0007] High-manganese steel is obtained by hot rolling, cold rolling, warm rolling, and low-temperature annealing of high-manganese steel billets.

[0008] As a further embodiment of the present invention, the hot rolling process is as follows: the high manganese steel billet is heated and then hot rolled to a thickness of 20-25 mm, and then air-cooled to room temperature.

[0009] Optionally, the lower limit of the thickness of the hot-rolled high-manganese steel billet is independently selected from 20mm, 21mm, 22mm, and 22.5mm, and the upper limit of the thickness of the hot-rolled high-manganese steel billet is independently selected from 23mm, 24mm, and 25mm.

[0010] As a further embodiment of the present invention: the hot rolling process specifically involves heating the high-manganese steel billet to 1100-1200°C, holding it at that temperature for more than 2 hours, and then performing multi-step hot rolling.

[0011] Preferably, in the hot rolling process, the reduction rate per pass is 20% to 25%.

[0012] Optionally, the lower limit of the hot rolling heating temperature is independently selected from 1100℃, 1110℃, 1120℃, 1130℃, and 1140℃; the upper limit of the hot rolling heating temperature is independently selected from 1150℃, 1160℃, 1170℃, 1180℃, 1190℃, and 1200℃.

[0013] Optionally, the heat preservation time can be independently selected from 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 6h, 7h, 8h, 9h, and 10h.

[0014] Optionally, the hot rolling pass reduction rate is independently selected from 20%, 21%, 22%, 23%, 24%, and 25%.

[0015] As a further aspect of the present invention, the cold rolling process is as follows: the hot-rolled high-manganese steel billet is cold-rolled to a thickness of 10-12 mm.

[0016] Optionally, the lower limit of the thickness of the cold-rolled high-manganese steel billet is independently selected from 10mm, 10.5mm, and 11mm, and the upper limit of the thickness of the cold-rolled high-manganese steel billet is independently selected from 11.5mm, 11.8mm, and 12mm.

[0017] As a further embodiment of the present invention: the total cold rolling reduction rate is 40-50%;

[0018] Preferably, the cold rolling pass reduction rate is ≥12%.

[0019] Optionally, the lower limit of the total cold rolling reduction rate is independently selected from 40%, 42%, 44%, and 45%; the upper limit of the total cold rolling reduction rate is independently selected from 46%, 48%, and 50%.

[0020] Optionally, the cold rolling pass reduction rate is independently selected from 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, 35%, 40%, 45%, and 50%.

[0021] As a further embodiment of the present invention, the warm rolling process is as follows: the cold-rolled high-manganese steel billet is warm-rolled to a thickness of 5-6 mm and then air-cooled to room temperature.

[0022] Optionally, the lower limit of the thickness of the high-manganese steel billet after warm rolling is independently selected from 5mm, 5.2mm, 5.4mm, and 5.5mm, and the upper limit of the thickness of the high-manganese steel billet after warm rolling is independently selected from 5.6mm, 5.8mm, and 6mm.

[0023] As a further embodiment of the present invention: the warm rolling temperature is 600-680℃, and the holding time is 0.2-1h;

[0024] Preferably, the warm rolling temperature is 630–670℃ and the holding time is 0.4–0.6h.

[0025] Optionally, the lower limit of the warm rolling temperature is independently selected from 600℃, 610℃, 620℃, 630℃, and 640℃; the upper limit of the warm rolling temperature is independently selected from 650℃, 660℃, 670℃, and 680℃.

[0026] Optionally, the lower limit of the warm rolling holding time is independently selected from 0.2h, 0.3h, 0.4h, 0.5h, and 0.6h; the upper limit of the warm rolling holding time is independently selected from 0.7h, 0.8h, 0.9h, and 1.0h.

[0027] As a further embodiment of the present invention: the total reduction rate during warm rolling is 50% to 65%;

[0028] Preferably, the reduction rate of the warm rolling pass is ≥20%.

[0029] In this invention, the lower limit of the total reduction rate in warm rolling is independently selected from 50%, 52%, 54%, and 56%; the upper limit of the total reduction rate in warm rolling is independently selected from 58%, 60%, 62%, 64%, and 65%.

[0030] Optionally, the reduction rate of the warm rolling pass is independently selected from 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38%, 40%, 45%, 50%, 55%, 60%, and 65%.

[0031] As a further embodiment of the present invention: the low-temperature annealing treatment is: heating and holding the warm-rolled high-manganese steel billet at a certain temperature, and then water-cooling it to room temperature;

[0032] Preferably, the temperature range for low-temperature annealing is 500–800℃, and the holding time is 0.2–1 h;

[0033] More preferably, the low-temperature annealing temperature range is 580–700℃, and the holding time is 0.3–0.4 h;

[0034] More preferably, the low-temperature annealing temperature range is 630℃, and the holding time is 0.35h.

[0035] Optionally, the lower limit of the low-temperature annealing temperature is independently selected from 500℃, 550℃, 580℃, 600℃, 620℃, 630℃, and 650℃; the upper limit of the low-temperature annealing temperature is independently selected from 680℃, 700℃, 750℃, and 800℃.

[0036] Optionally, the lower limit of the temperature holding time for low-temperature annealing is independently selected from 0.2h, 0.3h, 0.35h, 0.4h, and 0.5h; the upper limit of the temperature holding time for low-temperature annealing is independently selected from 0.6h, 0.7h, 0.8h, 0.9h, and 1.0h.

[0037] As a further embodiment of the present invention, the formula of the high-manganese steel billet is as follows: C: 0.2-0.6%; Si: 0.02-0.1%; Mn: 17.0-28.0%; Al: 0.5-3%; N: 0.004-0.010%; P: ≤0.005%; S: ≤0.002%; with the balance being Fe.

[0038] Optionally, the carbon content is independently selected from 0.2%, 0.3%, 0.4%, 0.5%, and 0.6%.

[0039] Optionally, the silicon content is independently selected from 0.02%, 0.04%, 0.06%, 0.08%, and 0.1%.

[0040] Optionally, the manganese content is independently selected from 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, and 28%.

[0041] Optionally, the aluminum content is independently selected from 0.5%, 0.8%, 1%, 1.5%, 2%, 2.5%, and 3%.

[0042] Optionally, the nitrogen content is independently selected from 0.004%, 0.005%, 0.006%, 0.007%, 0.008%, 0.009%, and 0.010%.

[0043] The beneficial effects of this invention are as follows:

[0044] This invention employs a hot-rolling + cold-rolling + warm-rolling + low-temperature annealing process. The hot and cold rolling processes induce sufficiently large deformation in the as-cast microstructure to refine the grains, eliminating casting defects and porosity, while simultaneously providing sufficient strain storage energy and nucleation driving force for subsequent dynamic recrystallization. Warm rolling generates a synergistic mechanism of dynamic recrystallization and dynamic recovery. Dynamic recrystallization produces a large number of fine ultrafine grains, providing grain boundary strengthening; dynamic recovery preserves the high dislocation density and dislocation wall morphology in the local matrix, providing dislocation strengthening. Low-temperature annealing produces static recrystallization, increasing the recrystallization fraction and the proportion of ultrafine grains. Traditional methods for preparing bulk heterogeneous high-manganese steel generally utilize large deformation cold rolling followed by single-step annealing to produce completely static recrystallization, resulting in very low dislocation density and insufficiently fine ultrafine grain size. This invention utilizes a combination of cold rolling and warm rolling multi-step processes, introducing a coupling mechanism of dynamic recovery, dynamic recrystallization, and static recrystallization to obtain a heterogeneous structure that mixes high dislocation density coarse grains (5μm) with submicron-level ultrafine grains (200-800nm). During low-temperature stretching, multiple strengthening and toughening mechanisms are generated, including dislocation strengthening, grain refinement strengthening, twin-induced plasticity, and back stress strengthening, exhibiting high yield strength, high plasticity, and excellent low-temperature toughness. Compared with existing processes, this invention's process can obtain high-manganese steel materials with low cost, good weldability, and superior mechanical properties, and is also easily implemented using existing equipment. Attached Figure Description

[0045] Figure 1 The electron backscattering diffraction microstructure, grain size distribution, and local orientation deviation of the high-manganese steel in Example 1 of this invention. Figure 1 a, 1b, 1c, where 1a is the microstructure inverse pole figure; 1b is the grain size distribution diagram; and 1c is the local orientation deviation diagram.

[0046] Figure 2 The electron backscattering diffraction structure, grain size distribution, and local orientation deviation of the high-manganese steel in Example 2 of this invention. Figure 2 a, 2b, 2c, where 2a is the microstructure inverse pole figure; 2b is the grain size distribution diagram; and 2c is the local orientation deviation diagram.

[0047] Figure 3 The electron backscattering diffraction microstructure, grain size distribution, and local orientation deviation of the high-manganese steel in Example 3 of this invention. Figure 3 a, 3b, 3c, where 3a is the microstructure inverse pole figure; 3b is the grain size distribution diagram; and 3c is the local orientation deviation diagram.

[0048] Figure 4 The electron backscattering diffraction microstructure, grain size distribution, and local orientation deviation of the high-manganese steel in Comparative Example 1 of this invention are shown. Figure 4 a, 4b, 4c, where 4a is the microstructure inverse pole figure; 4b is the grain size distribution diagram; and 4c is the local orientation deviation diagram.

[0049] Figure 5 This is a comparison chart of the impact toughness of high manganese steel in Examples 1-4 and Comparative Examples 1-2 at 25°C and -196°C. Detailed Implementation

[0050] The present invention will be further illustrated below with reference to specific embodiments and comparative examples. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0051] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0052] Example 1

[0053] The original high-manganese steel billet No. 1, with a thickness of 50 mm and Fe-17Mn-0.6C-3Al-0.1Si-0.01N-0.004P-0.002S (wt.%), was subjected to hot rolling, cold rolling, warm rolling, and low-temperature annealing treatments, as follows:

[0054] (1) Heat to 1200℃ and hold for 2 hours, then perform multi-step hot rolling to 20mm thickness, with a pass reduction of 25%, and air cool to room temperature;

[0055] (2) Cold rolling: The hot-rolled steel plate is cold-rolled to a thickness of 12mm, with a total cold rolling reduction of 40% and a pass reduction of 15%.

[0056] (3) Warm rolling: The cold-rolled steel plate is heated to 600℃, held for 1 hour and then warm rolled to 4.2mm thickness. The total reduction rate of warm rolling is 65%, the reduction rate per pass is 20%, and it is air-cooled to room temperature.

[0057] (4) Low temperature annealing treatment: The steel plate after warm rolling is heated to 800℃ and held for 0.2h, and then cooled to room temperature by water.

[0058] The high-manganese steel sample No. 1 after rolling and heat treatment was examined under the electron backscatter diffraction probe of a scanning electron microscope. Specific microstructure, grain size distribution, and local orientation deviation diagrams are shown below. Figure 1 a, 1b, and 1c.

[0059] Example 2

[0060] The original high-manganese steel billet No. 2, with a thickness of 50 mm and Fe-28Mn-0.2C-0.5Al-0.02Si-0.004N-0.004P-0.002S (wt.%), was subjected to hot rolling, cold rolling, warm rolling, and low-temperature annealing treatments, as follows:

[0061] (1) Heat to 1100℃ and hold for 2 hours, then perform multi-step hot rolling to 20mm thickness, with a pass reduction of 25%, and air cool to room temperature;

[0062] (2) Cold rolling: The hot-rolled steel plate is cold-rolled to a thickness of 10mm, with a total cold rolling reduction rate of 50% and a pass reduction rate of 15%.

[0063] (3) Warm rolling: The cold-rolled steel plate is heated to 680℃, held for 0.2h and then warm rolled to 5mm thickness. The total reduction rate of warm rolling is 50%, the reduction rate per pass is 20%, and then air-cooled to room temperature.

[0064] (4) Low temperature annealing treatment: The steel plate after warm rolling is heated to 500℃ and held for 1 hour, and then cooled to room temperature by water.

[0065] The high-manganese steel sample No. 2 after rolling and heat treatment was examined under the electron backscatter diffraction probe of a scanning electron microscope. Specific microstructure, grain size distribution, and local orientation deviation diagrams are shown below. Figure 2 a, 2b, and 2c.

[0066] Example 3

[0067] The original high-manganese steel billet No. 3, with a thickness of 50 mm and Fe-24Mn-0.45C-2Al-0.08Si-0.004N-0.004P-0.002S (wt.%), was subjected to hot rolling, cold rolling, warm rolling, and low-temperature annealing treatments, as follows:

[0068] (1) Heat to 1150℃ and hold for 2 hours, then perform multi-step hot rolling to 20mm thickness, with a pass reduction of 25%, and air cool to room temperature;

[0069] (2) Cold rolling: The hot-rolled steel plate is cold-rolled to a thickness of 10mm, with a total cold rolling reduction rate of 50% and a pass reduction rate of 15%.

[0070] (3) Warm rolling: The cold-rolled steel plate is heated to 630℃, held for 0.5h and then warm rolled to 5.5mm thickness. The total reduction rate of warm rolling is 55%, the reduction rate per pass is 20%, and it is air-cooled to room temperature.

[0071] (4) Low-temperature annealing treatment: The steel plate after warm rolling is heated to 630℃ and held for 0.4h, and then cooled to room temperature by water.

[0072] The high-manganese steel sample No. 3, after rolling and heat treatment, was examined under the electron backscatter diffraction probe of a scanning electron microscope. Specific microstructure, grain size distribution, and local orientation deviation diagrams are shown below. Figure 3 a, 3b, and 3c.

[0073] Example 4

[0074] The original high-manganese steel billet No. 4, with a thickness of 50mm and Fe-22Mn-0.6C-1.5Al-0.08Si-0.004N-0.004P-0.002S (wt.%), was subjected to hot rolling, cold rolling, warm rolling, and low-temperature annealing treatments, as follows:

[0075] (1) Heat to 1200℃ and hold for 2 hours, then perform multi-step hot rolling to 20mm thickness, with a pass reduction of 25%, and air cool to room temperature;

[0076] (2) Cold rolling: The hot-rolled steel plate is cold-rolled to 11mm thickness, with a total cold rolling reduction rate of 45% and a pass reduction rate of 15%.

[0077] (3) Warm rolling: The cold-rolled steel plate is heated to 630℃, held for 0.5h and then warm rolled to 5mm thickness. The total reduction rate of warm rolling is 50%, the reduction rate per pass is 20%, and then air-cooled to room temperature.

[0078] (4) Low temperature annealing treatment: The steel plate after warm rolling is heated to 680℃ and held for 0.3h, and then cooled to room temperature by water.

[0079] Comparative Example 1

[0080] The original high-manganese steel billet No. 5, with a thickness of 50 mm and Fe-24Mn-0.45C-2Al-0.08Si-0.004N-0.004P-0.002S (wt.%), was subjected to hot rolling, cold rolling, and low-temperature annealing treatment, as follows:

[0081] (1) Heat to 1200℃ and hold for 2 hours, then perform multi-step hot rolling to 20mm thickness, with a pass reduction of 25%, and air cool to room temperature;

[0082] (2) Cold rolling: The hot-rolled steel plate is cold-rolled to a thickness of 10mm, with a total cold rolling reduction rate of 50% and a pass reduction rate of 15%.

[0083] (3) Low temperature annealing treatment: The steel plate after warm rolling is heated to 680℃ and held for 0.2h, and then cooled to room temperature by water.

[0084] The high-manganese steel sample No. 1 after rolling and heat treatment was examined under the electron backscatter diffraction probe of a scanning electron microscope. Specific microstructure, grain size distribution, and local orientation deviation diagrams are shown below. Figure 4 a, 4b, and 4c.

[0085] Comparative Example 2

[0086] The original high-manganese steel billet No. 6, with a thickness of 50 mm and Fe-24Mn-0.45C-2Al-0.08Si-0.004N-0.004P-0.002S (wt.%), was subjected to hot rolling, cold rolling, warm rolling, and low-temperature annealing treatments, as follows:

[0087] (1) Heat to 1200℃ and hold for 2 hours, then perform multi-step hot rolling to 20mm thickness, with a pass reduction of 25%, and air cool to room temperature;

[0088] (2) Cold rolling: The hot-rolled steel plate is cold-rolled to a thickness of 10mm, with a total cold rolling reduction rate of 50% and a pass reduction rate of 15%.

[0089] (3) Warm rolling: The cold-rolled steel plate is heated to 500℃, held for 0.5h and then warm rolled to 5mm thickness. The total reduction rate of warm rolling is 50%, the reduction rate per pass is 20%, and then air-cooled to room temperature.

[0090] (3) Low temperature annealing treatment: The steel plate after warm rolling is heated to 680℃ and held for 0.2h, and then cooled to room temperature by water.

[0091] Example 5

[0092] The high-manganese steel samples 1#, 2#, 3#, and 5# from Examples 1-3 and Comparative Example 1 were observed for grain size distribution and dislocation density using electron backscattering diffraction. Specific results are shown in [link to results]. Figure 1 , Figure 2 , Figure 3 , Figure 4 .

[0093] Depend on Figure 1 a- Figure 4 As can be seen from a, after multiple rolling steps and subsequent low-temperature annealing, the grain size of high manganese steel exhibits a clear bicrystalline distribution phenomenon: the grains of samples 1#-3# are heterogeneous structures consisting of equiaxed fine grains and elongated coarse grains, while the grains of sample 5# are all equiaxed ultrafine grains.

[0094] Depend on Figure 1 b- Figure 4 b indicates that the fine grain size of sample 5 is coarser than that of samples 1-3, while the coarse grain size is smaller. That is, the grain size distribution of samples 1-3 is wider and the average grain size is smaller.

[0095] Depend on Figure 1 c- Figure 4 As can be seen from c, samples 1#-3# have a high dislocation density, and local high-density dislocation walls can be observed in the coarse-grained region, while sample 5# is in a completely recrystallized state with a very low dislocation density.

[0096] Example 6

[0097] Tensile tests were conducted on high-manganese steel samples 1#-6# from Examples 1-4 and Comparative Examples 1-2 at liquid nitrogen temperature. The tensile tests were performed according to ASTM standard (E 8M-04), with the tensile direction along the rolling direction, on a Zwick / Roell Z100 universal testing machine. The specific results are shown in Table 1.

[0098] Table 1. Test results of the embodiments and comparative sample of the present invention.

[0099]

[0100] As shown in Table 1, after multi-step rolling and low-temperature annealing, the yield strength, tensile strength, uniform elongation, and strength-ductility product of the six samples at liquid nitrogen temperature were significantly improved compared to those at room temperature. The low-temperature yield strength of the high-manganese steel samples 1-4# in Examples 1-4 all reached over 1100 MPa. Sample 5#, obtained without an intermediate warm rolling process, had the lowest low-temperature yield strength. Sample 6#, rolled at a lower temperature, achieved a yield strength above 1100 MPa, but its elongation was very low, only 30.5%. More importantly, compared to samples 5# and 6#, samples 1#-4# showed a significant increase in yield strength, while also increasing low-temperature elongation to 74%, with an overall strength-ductility product at low temperature reaching 110 GPa.%. This is attributed to the coupled strengthening and toughening mechanism of fine-grain strengthening, dislocation strengthening, twinning-induced plasticity, and back stress strengthening. By controlling the grain size distribution and dislocation density, yield strength, plasticity, and strength-ductility product were simultaneously improved.

[0101] Example 7

[0102] High-manganese steel samples 1-6# from Examples 1-4 and Comparative Examples 1-2 were subjected to impact tests at room temperature and liquid nitrogen temperature, respectively. Standard Charpy V-notch specimens were used, and the tests were conducted on a 300J impact testing machine. Specific results are shown in […]. Figure 5 After multiple rolling and low-temperature annealing processes, samples 1-4 also achieved higher impact toughness values ​​(110-140 J·cm) at liquid nitrogen temperature compared to samples 5 and 6. -2 This significantly exceeds the ASTM standard value of 42.5 J / cm for impact toughness of high manganese steel. 2 While possessing high yield strength and high plasticity, it can still ensure very high low-temperature toughness, thus obtaining a high-strength and high-toughness high-manganese steel for ultra-low temperatures.

[0103] In summary, this invention effectively overcomes the various shortcomings of the prior art and has high industrial application value.

[0104] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for producing a high-manganese steel having high yield strength, high ductility and high low-temperature toughness, characterized by, The method comprises the following steps: high manganese steel billets are processed by hot rolling, cold rolling, warm rolling and low temperature annealing to obtain high manganese steel, and the formula of the high manganese steel billets is as follows: C: 0.2-0.6%; Si: 0.02-0.1%; Mn: 17.0-28.0%; Al：0.5～3%； N：0.004～0.010%； P：≤0.005%； S: ≤0.002%; the balance is Fe; Specifically, the method comprises the following steps: (1) the high manganese steel billets are heated to 1100-1200 DEG C and kept for more than 2 hours, and then multi-step hot rolling is performed with a pass reduction rate of 20-25%, and the high manganese steel billets are rolled to a thickness of 20-25 mm and air-cooled to room temperature; (2) the high manganese steel billets after hot rolling are cold rolled to a thickness of 10-12 mm, and the total cold rolling reduction rate is 40-50%, and the pass reduction rate of cold rolling is greater than or equal to 12%; (3) the high manganese steel billets after cold rolling are warm rolled at a temperature of 600-680 DEG C for 0.2-1 hours, and the high manganese steel billets are rolled to a thickness of 5-6 mm and air-cooled to room temperature, and the total warm rolling reduction rate is 50-65%, and the pass reduction rate of warm rolling is greater than or equal to 20%; (4) the high manganese steel billets after warm rolling are heated and kept, and then water-cooled to room temperature to obtain high manganese steel, and the low temperature annealing temperature is 500-800 DEG C, and the keeping time is 0.2-1 hours.

2. The method of producing high-manganese steel with high yield strength, high ductility and high low-temperature toughness according to claim 1, characterized in that, The warm rolling temperature is 630-670 DEG C, and the keeping time is 0.4-0.6 hours.

3. The method of producing high-manganese steel with high yield strength, high ductility and high low-temperature toughness according to claim 1, characterized in that, The low temperature annealing temperature is 580-700 DEG C, and the keeping time is 0.3-0.4 hours.

4. The method of producing high-manganese steel with high yield strength, high ductility and high low-temperature toughness according to claim 3, characterized in that, The low temperature annealing temperature is 630 DEG C, and the keeping time is 0.35 hours.

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