Wear-resistant high-manganese steel and preparation method thereof

Abstract

The invention discloses wear-resistant high-manganese steel and a preparation method thereof, and belongs to the technical field of wear-resistant steel. The wear-resistant high manganese steel comprises the following components in percentage by mass: 0.9-1.1% of C, 0.2-0.6% of Si, 17-19% of Mn, 1.5-2.5% of Cr, less than or equal to 0.003% of P, less than or equal to 0.003% of S, less than or equal to 0.003% of Al and the balance of Fe. The preparation method of the wear-resistant high-manganese steel comprises the following steps: S1, weighing the raw materials according to the composition proportion, and smelting the raw materials to obtain a solution; s2, the solution is subjected to continuous casting, a casting blank with the thickness ranging from 150 mm to 300 mm is obtained, fixed-length cutting is conducted on the casting blank, and a plate blank is obtained; s3, the plate blank is put into a heating furnace to be heated, hot rolling is conducted on the plate blank, and a rolled plate with the thickness ranging from 2 mm to 50 mm is obtained; s4, the rolled plate is subjected to solid solution water toughening heat treatment; and S5, the rolled plate is subjected to finishing and shearing, and the wear-resistant steel plate is obtained. By adopting the wear-resistant high-manganese steel and the preparation method thereof, the problems that existing high-manganese steel is low in tensile strength, poor in comprehensive performance and complex in manufacturing process can be solved.

Description

Technical Field

[0001] The invention relates to the technical field of wear-resistant steel, in particular to a wear-resistant high manganese steel and a preparation method thereof. Background Art

[0002] Wear-resistant high manganese steel plays an important role in many fields such as mining, construction, railway, agricultural machinery and steel industry with its unique high wear resistance and good toughness. The traditional production process of wear-resistant high manganese steel is to use sand casting. The material utilization rate of sand casting is relatively low, and the manufacturing process is complicated, the scrap rate of finished parts is high, and the difficulty of machining is relatively large. In addition, the internal structure of cast high manganese steel is loose, and casting defects such as sand holes and pores cannot be avoided, which affects the wear resistance of high manganese steel products.

[0003] Existing patent 202210711116.0 discloses a low-cost high manganese steel plate and its production method. The chemical composition and mass percentage of the low-cost high manganese steel plate are: C: 0.44-0.60%, Si: 0.22-0.60%, Mn: 22-26%, P≤0.010%, S≤0.005%, Cr: 3-6%, Al: 0.02-0.07%, N: 0.08-0.12%, and the balance is Fe and unavoidable impurities. The production method includes smelting, heating, rolling, and relaxation cooling processes. The present invention does not need to add precious Ni elements, makes full use of N elements to expand the austenite zone, and cooperates with high-temperature rolling and post-rolling relaxation cooling processes to obtain high-manganese steel plates with excellent comprehensive mechanical properties and good low-temperature impact toughness. It can be used as a new steel material for LNG storage tanks; at the same time, the production process does not require heat treatment, and the production cost is low. Although the above patent discloses the production of high manganese steel plates by rolling, the yield strength of the obtained high manganese steel plates is 450 MPa and the tensile strength is 870 MPa, and the strength of the high manganese steel plates is relatively low. Summary of the invention

[0004] The purpose of the present invention is to provide a wear-resistant high manganese steel and a preparation method thereof, so as to solve the problems of low tensile strength, poor comprehensive performance and complicated manufacturing process of the existing high manganese steel.

[0005] To achieve the above-mentioned object, the present invention provides a wear-resistant high manganese steel, comprising the following components in mass percentage: C 0.9%-1.1%, Si 0.2%-0.6%, Mn 17%-19%, Cr 1.5%-2.5%, P ≤0.003%, S ≤0.003%, Al ≤0.003%, and the balance Fe.

[0006] Preferably, the alloy comprises the following components in mass percentage: C 1.0%, Si 0.3%, Mn 18%, Cr 2%, P ≤0.002%, S ≤0.003%, Al ≤0.003%, rare earth 0.1%, and the balance Fe.

[0007] The preparation method of wear-resistant high manganese steel comprises the following steps: S1. Weigh the raw materials according to the component ratio, and melt the raw materials to obtain a solution; S2, continuously casting the solution to obtain a casting billet with a thickness of 150 mm to 300 mm, and cutting the casting billet to a fixed length to obtain a slab; S3, placing the slab into a heating furnace for heating, and hot rolling the slab to obtain a rolled plate with a thickness of 2 mm to 50 mm; S4, performing solution water toughening heat treatment on the rolled plate; S5. Finish the rolled plate and obtain the wear-resistant steel plate after shearing.

[0008] Preferably, in S1, smelting comprises the following steps: S11, placing the weighed raw materials into an EAF furnace for smelting; S12, after 60 minutes of power on, blowing oxygen into the EAF furnace for fluxing; S13, after the melting is complete, the mass percentage of C in the molten steel is 0.05%-0.1%; remove the oxide slag, add CaO slag to the solution, add Al powder, C powder and Si powder to reduce the slag after it is evenly mixed; S14, analyzing the composition of the molten steel, adjusting the Mn element content in the molten steel according to the composition ratio; removing the slag before tapping, adding CaO slag material for homogenization, and the oxygen activity in the molten steel is ≤1000ppm; S15. Refining is carried out in a LF furnace. Deoxidizer and CaO slag are added to the ladle. Silica is added to the ladle, and high-purity argon is introduced for refining. After stirring the slag for 3min-5min, the Ca wire is fed, the composition of the molten steel is adjusted, the calming time is not less than 3min, carbonized rice is added for heat preservation, and the ladle is poured.

[0009] Preferably, in S13, the addition amount of CaO slag is 0.5%-1.5%.

[0010] Preferably, in S14, the steel tapping temperature is 1600°C-1650°C.

[0011] Preferably, in S15, the pouring temperature of the first ladle is 1445°C-1450°C, and the pouring temperature of the following ladle is 1442°C-1447°C.

[0012] Preferably, in S2, the temperature of the molten steel in the continuous casting tundish is 1410°C-1435°C, the pulling speed is 0.4m / min-1.0m / min, and the emergence time is 120 seconds-150 seconds.

[0013] Preferably, in S3, the temperature of the preheating section of the heating furnace is 600℃-800℃, the temperature of the heating section is 1150℃-1200℃, the temperature of the soaking section is 1150℃-1200℃, the preheating time of the slab in the preheating section is not less than 30min, and the heating time of the slab in the heating furnace is not less than 4h; the second opening temperature of hot rolling is not less than 1000℃, and the final rolling temperature is not less than 820℃.

[0014] Preferably, in S4, the heat treatment temperature of the solution heat treatment is 1000°C-1100°C, the holding time is 1.5 min / 1 mm thickness, and the cooling is water cooling to room temperature within 1 min.

[0015] The advantages and positive effects of the wear-resistant high manganese steel and the preparation method thereof of the present invention are: 1. The present invention reduces the cost of materials and improves the plasticity and toughness of materials while obtaining high-strength steel plates by adjusting the contents of Mn, Si, C and Cr elements in high manganese steel, thereby having good comprehensive mechanical properties.

[0016] 2. The present invention adopts continuous casting and hot rolling to produce high manganese steel, and rolls high manganese steel into steel plates, which increases the material utilization rate by more than 30%, and the steel plates can be cut and bent as needed, which expands the application range of high manganese steel and is suitable for large-scale production. The high manganese steel prepared by hot rolling has a dense and uniform internal structure and more stable performance, which is conducive to improving the wear resistance of high manganese steel.

[0017] 3. The present invention performs a solution heat treatment on the hot-rolled steel plate, heats the rolled plate to 1050°C for insulation, so that the second phase particles are fully dissolved in the matrix, and then quickly cools it to room temperature to avoid the re-precipitation of the second phase particles, thereby improving the overall toughness and ductility of the material and improving the machinability of the material; the solution heat treatment can reduce the residual stress inside the material, and the rapid cooling helps to form a fine and uniform microstructure, thereby improving the wear resistance and toughness of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The present invention is a preparation flow chart of an embodiment of the present invention. DETAILED DESCRIPTION

[0019] A wear-resistant high manganese steel comprises the following components in percentage by mass: C 0.9%-1.1%, Si 0.2%-0.6%, Mn17%-19%, Cr 1.5%-2.5%, P ≤0.003%, S ≤0.003%, Al ≤0.003%, and the balance Fe.

[0020] Mn: As the main alloying element of high manganese steel, high concentration of manganese (usually more than 10%) can form austenite structure, providing good toughness and ductility. Manganese can also combine with sulfur (S) to form MnS, avoiding brittleness caused by sulfides. However, too high Mn elements increase the hardness and brittleness of the material, affect the deformation ability of the material, and make processing difficult; and too much Mn elements will lead to coarse grains and weaken the toughness and plasticity of the material. Therefore, the content of Mn elements is controlled at 17%-19%.

[0021] C: The carbon content will affect the hardness and wear resistance of high manganese steel. The right amount of carbon helps to form hard carbides, enhance wear resistance, and carbon can maintain the austenite structure and ensure the hardness of high manganese steel. However, too much carbon will reduce the toughness of the material. Therefore, the content of C element is controlled at 0.9%-1.1%.

[0022] Cr: Enhances corrosion resistance and wear resistance, promotes the formation of dense austenite grains, and forms hard carbides with carbon. However, too much chromium not only increases material cost, but also increases welding difficulty and causes cracking problems. And too much chromium will promote uneven distribution of hard phases and affect the comprehensive mechanical properties of the material. Chromium will also complicate phase change behavior during heat treatment, resulting in poor controllability of the material. Therefore, the content of Cr is controlled at 1.5%-2.5%.

[0023] Si: Silicon can promote the formation of austenite, and work with manganese to improve the hardenability of the material, which helps to obtain a uniform microstructure and improve the overall performance of the material. However, too high a silicon content will increase the hardness and brittleness of the material, affect the toughness and plasticity of the material, and lead to poor forming performance of the material. Therefore, the content of Si is controlled at 0.2%-0.6%.

[0024] The preparation method of wear-resistant high manganese steel comprises the following steps: S1. Weigh the raw materials according to the component ratio, and melt the raw materials to obtain a solution.

[0025] Smelting includes the following steps: S11. Put the weighed raw materials into the EAF furnace for smelting. P in the molten metal is ≤ 0.04%.

[0026] S12. After 60 minutes of power-on, oxygen is blown into the EAF furnace for fluxing.

[0027] S13. After complete melting, the mass percentage of C in the molten steel is 0.05%-0.1%, the slag P≤0.005%, and the slag temperature is not less than 1630℃. Clear the oxide slag, add CaO slag to the solution, and the addition amount of CaO slag is 0.5%-1.5%. After the slag is homogenized, add Al powder, C powder and Si powder to reduce and make white slag.

[0028] S14. After the slag changes color, the steel liquid is analyzed for components. Carbon manganese, medium carbon manganese and electrolytic manganese are added to the steel liquid according to the composition ratio to adjust the Mn element content in the steel liquid. C powder and Si powder are added to the steel liquid for reduction. Before tapping, part of the slag is removed and CaO slag is added for homogenization.

[0029] Before tapping, keep as much slag as possible, and the slag added during tapping flows into the ladle along with the molten steel. Before tapping, the molten steel should be oxygenated, and C powder or C balls should be added for deoxidation according to the oxygen activity, and the oxygen activity in the molten steel should be controlled to be ≤1000ppm. Add 2.5kg / t of SiAl into the ladle.

[0030] The tapping temperature is 1600℃-1650℃.

[0031] S15. Refining is performed in a LF furnace, and the final composition of the molten steel is determined in the LF furnace.

[0032] Add deoxidizer and CaO slag into the ladle. In a 40-ton ladle, add CaO slag into the ladle in 1-3 batches, with each batch adding 100-300kg of CaO slag and the total amount of CaO slag added not exceeding 300kg. When adding CaO slag, ensure that the slag has good fluidity and the slag color turns white. SiFe powder or C powder is used to deoxidize the slag surface in the ladle.

[0033] Add 130kg of silica to the ladle, and introduce high-purity argon for stirring and refining. The Ar gas flow rate is controlled in principle so that the molten steel does not turn over the slag surface. After stirring and slagging for 3min-5min, feed 80-100m of Ca wire, adjust the final composition of the molten steel, and the calming time is not less than 3min. Add carbonized rice for heat preservation, and pour from the hanging ladle.

[0034] The liquidus temperature of molten steel is 1380℃. The pouring temperature of the first ladle is 1445℃-1450℃, and the pouring temperature of the follower ladle is 1442℃-1447℃. If it is a cold ladle or a standby ladle, the ladle temperature needs to be increased by 5℃.

[0035] S2, continuously casting the solution to obtain a casting billet with a thickness of 150 mm to 300 mm, and cutting the casting billet to a predetermined length to obtain a slab.

[0036] For a slab with a thickness of 200 mm, the size of the submerged nozzle is 80 mm*40 mm, the inclination angle is 15°, and the immersion depth is 90 mm-100 mm.

[0037] The water volume of the crystallizer is 2300L / min on the wide side and 320L / min on the narrow side. The taper of the crystallizer is 1.25, and the width shrinkage of the casting is 1.027%.

[0038] The temperature of the continuous casting tundish is ≥1000℃ and the baking time is not less than 4 hours.

[0039] The temperature of the molten steel in the continuous casting tundish is 1410℃-1435℃. The pulling speed is 0.4m / min-0.6m / min, and the emergence time is 120s-150s. The relationship between the pouring temperature and the pulling speed of the slab with a thickness of 200mm is shown in Table 1.

[0040] Table 1 Corresponding relationship between pouring temperature and casting speed of 200mm billet

[0041] For a slab with a thickness of 150 mm, the size of the submerged nozzle is 80 mm*40 mm, the inclination angle is 15°, and the immersion depth is 90 mm-100 mm.

[0042] The water volume of the crystallizer is 2750L / min on the wide side and 250L / min on the narrow side. The taper of the crystallizer is 1.25, and the width shrinkage of the ingot is 1.027%.

[0043] The temperature of the continuous casting tundish is ≥1000℃ and the baking time is not less than 4 hours.

[0044] The temperature of the molten steel in the continuous casting tundish is 1410℃-1435℃. The pulling speed is 0.7m / min-1.0m / min, and the emergence time is 120s-150s. The relationship between the pouring temperature and the pulling speed of the slab with a thickness of 150mm is shown in Table 2.

[0045] Table 2 Corresponding relationship between pouring temperature and casting speed of 150mm billet

[0046] The ingot is cooled to 400°C and cut to a fixed length to obtain a slab, which is then hot-transferred to a heating furnace for hot rolling.

[0047] S3, placing the slab into a heating furnace for heating, and hot rolling the slab to obtain a rolled plate.

[0048] The temperature of the preheating section of the heating furnace is 600℃-800℃, the temperature of the heating section is 1150℃-1200℃, and the temperature of the soaking section is 1150℃-1200℃. The preheating time of the slab in the preheating section is not less than 30min, and the heating time of the slab in the heating furnace is not less than 4h.

[0049] Before hot rolling, the slab needs to be dephosphorized. Precise dephosphorization is performed in the first few passes of the rough rolling stage to ensure that the slab surface is completely dephosphorized and the iron oxide scale is removed. In the finishing rolling stage, according to the actual steel temperature and the condition of the surface iron oxide scale, 1-2 more dephosphorizations are appropriately added to ensure that the iron oxide scale is completely removed. The dephosphorization water pressure is not less than 15MPa.

[0050] The rolling process includes flattening by the roughing mill, widening by the roughing mill, and lengthening by the finishing mill.

[0051] Adjust the direction of the billet to ensure that the first small end enters the rolling mill. According to the thickness of the small end of the billet and the length of the intermediate billet after flattening, flattening rolling is carried out on the basis of ensuring that the length of the intermediate billet is ≤2400mm.

[0052] According to the size of the billet after flattening, calculate the widening position of the small end width, and take the widening position of the small end width as the order width.

[0053] The second rolling temperature shall not be less than 1000℃, no temperature control in the middle, and the final rolling temperature shall not be less than 820℃.

[0054] The thickness of the rolled plate after finish rolling is 2mm-50mm.

[0055] Main points of operation in the rough rolling stage: 1. In the longitudinal rolling and flattening stage, the small end of each pass enters the rolling mill and needs to turn 180° after the mill; 2. Use the outer head of the push bed to clamp the small end of the blank to make it as centered as possible; 3. To reduce temperature drop, the descaling frequency should be determined according to the condition of the oxidized iron scale.

[0056] Key points of finishing rolling operation: 1. During the rolling process, use the pusher to clamp the steel plate appropriately and then gradually open it a little to ensure that the big end does not hang on the pusher and try to ensure that the steel plate is centered; 2. The rolling mill should prepare steel wire ropes in advance to lift the steel plates. If large bends or hanging frames occur during the rolling process, it is strictly forbidden to enter the rolling mill.

[0057] S4. Perform solution water toughening heat treatment on the rolled plate.

[0058] The heat treatment temperature of the solution heat treatment is 1000℃-1100℃, the insulation time is 1.5min for every 1mm thickness, and the cooling time is water cooling to room temperature within 1min.

[0059] Solution heat treatment allows the second phase particles to be fully dissolved in the matrix, and then quickly cooled to room temperature to avoid the re-precipitation of the second phase particles, thereby improving the overall toughness and ductility of the material and improving the material's machinability; solution heat treatment can reduce the residual stress inside the material, and rapid cooling helps to form a fine and uniform microstructure, improving the wear resistance and toughness of the material.

[0060] S5. Finish the rolled plate and obtain the wear-resistant steel plate after shearing.

[0061] Before straightening the rolled plate, the temperature of the rolled plate shall not be lower than 650°C. The roll gap setting shall be adjusted according to the positive tolerance of Q235B, and the roll gap can be appropriately raised according to the actual situation to protect the working roll surface of the straightening machine.

[0062] Example 1

[0063] The preparation method of wear-resistant high manganese steel comprises the following steps: S1. Weigh the raw materials according to the component ratio, and melt the raw materials to obtain a solution.

[0064] Smelting includes the following steps: S11. Put the weighed raw materials into the EAF furnace for smelting. P in the molten metal is ≤ 0.04%.

[0065] S12. After 60 minutes of power-on, oxygen is blown into the EAF furnace for fluxing.

[0066] S13. After complete melting, the mass percentage of C in the molten steel is 0.05%-0.1%, the slag P≤0.005%, and the slag temperature is not less than 1630℃. Clear the oxide slag, add CaO slag to the solution, and the addition amount of CaO slag is 0.5%-1.5%. After the slag is homogenized, add Al powder, C powder and Si powder to reduce and make white slag.

[0067] S14. After the slag changes color, the steel liquid is analyzed for components. Carbon manganese, medium carbon manganese and electrolytic manganese are added to the steel liquid according to the composition ratio to adjust the Mn element content in the steel liquid. C powder and Si powder are added to the steel liquid for reduction. Before tapping, part of the slag is removed and CaO slag is added for homogenization.

[0068] Before tapping, keep as much slag as possible, and the slag added during tapping flows into the ladle along with the molten steel. Before tapping, the molten steel should be oxygenated, and C powder or C balls should be added for deoxidation according to the oxygen activity, and the oxygen activity in the molten steel should be controlled to be ≤1000ppm. Add 2.5kg / t of SiAl into the ladle.

[0069] The steel tapping temperature is 1610℃.

[0070] S15. Refining is performed in a LF furnace, and the final composition of the molten steel is determined in the LF furnace.

[0071] Add deoxidizer and CaO slag into the ladle. Add CaO slag into the ladle in 3 batches in a 40-ton ladle, with 100 kg added to each batch. When adding CaO slag, ensure that the slag has good fluidity and the slag color turns white. Use SiFe powder or C powder to deoxidize the slag surface in the ladle.

[0072] 130kg of silica is added to the ladle, and high-purity argon is introduced for stirring and refining. The Ar gas flow rate is controlled in principle so that the molten steel does not turn over the slag surface. After stirring and slagging for 5 minutes, 80 meters of Ca wire is fed, and the final composition of the molten steel is adjusted. The calming time is not less than 3 minutes, and carbonized rice is added for heat preservation, and the ladle is poured.

[0073] The liquidus temperature of molten steel is 1380℃. The pouring temperature of the first ladle is 1445℃-1450℃, and the pouring temperature of the follower ladle is 1442℃-1447℃. If it is a cold ladle or a standby ladle, the ladle temperature needs to be increased by 5℃.

[0074] S2, continuously casting the solution to obtain a 150 mm thick ingot, and cutting the ingot to a predetermined length to obtain a slab.

[0075] The size of the immersion nozzle is 80mm*40mm, the inclination angle is 15°, and the immersion depth is 95mm.

[0076] The water volume of the crystallizer is 2750L / min on the wide side and 250L / min on the narrow side. The taper of the crystallizer is 1.25, and the width shrinkage of the ingot is 1.027%.

[0077] The temperature of the continuous casting tundish is ≥1000℃ and the baking time is not less than 4 hours.

[0078] The temperature of the molten steel in the continuous casting tundish is 1410°C-1420°C. The pulling speed is 0.96m / min-1.0m / min, and the emergence time is 120 seconds.

[0079] The ingot is cooled to 400°C and cut to a fixed length to obtain a slab, which is then hot-transferred to a heating furnace for hot rolling.

[0080] S3, placing the slab into a heating furnace for heating, and hot rolling the slab to obtain a rolled plate.

[0081] The temperature of the preheating section of the heating furnace is 600°C, the temperature of the heating section is 1150°C, and the temperature of the soaking section is 1150°C. The preheating time of the slab in the preheating section is 30 minutes, and the heating time of the slab in the heating furnace is 4 hours.

[0082] Before hot rolling, the slab needs to be dephosphorized. Precise dephosphorization is performed in the first few passes of the rough rolling stage to ensure that the slab surface is completely dephosphorized and the iron oxide scale is removed. In the finishing rolling stage, according to the actual steel temperature and the condition of the surface iron oxide scale, 1-2 more dephosphorizations are appropriately added to ensure that the iron oxide scale is completely removed. The dephosphorization water pressure is not less than 15MPa.

[0083] The rolling process includes flattening by the roughing mill, widening by the roughing mill, and lengthening by the finishing mill.

[0084] Adjust the direction of the billet to ensure that the first small end enters the rolling mill. According to the thickness of the small end of the billet and the length of the intermediate billet after flattening, flattening rolling is carried out on the basis of ensuring that the length of the intermediate billet is ≤2400mm.

[0085] According to the size of the billet after flattening, calculate the widening position of the small end width, and take the widening position of the small end width as the order width.

[0086] The second rolling temperature is not less than 1000℃, there is no temperature control in the middle, and the final rolling temperature is 820℃.

[0087] The thickness of the rolled plate after finish rolling is 10 mm.

[0088] S4. Perform solution water toughening heat treatment on the rolled plate.

[0089] The heat treatment temperature of the solution heat treatment is 1050℃, the holding time is 15min, and the cooling time is 40S.

[0090] S5. Finish the rolled plate and obtain the wear-resistant steel plate after shearing.

[0091] Example 2

[0092] The preparation method of wear-resistant high manganese steel comprises the following steps: S1. Weigh the raw materials according to the component ratio, and melt the raw materials to obtain a solution.

[0093] Smelting includes the following steps: S11. Put the weighed raw materials into the EAF furnace for smelting. P in the molten metal is ≤ 0.04%.

[0094] S12. After 60 minutes of power-on, oxygen is blown into the EAF furnace for fluxing.

[0095] S13. After complete melting, the mass percentage of C in the molten steel is 0.05%-0.1%, the slag P≤0.005%, and the slag temperature is not less than 1630℃. Clear the oxide slag, add CaO slag to the solution, and the addition amount of CaO slag is 0.5%-1.5%. After the slag is homogenized, add Al powder, C powder and Si powder to reduce and make white slag.

[0096] S14. After the slag changes color, the steel liquid is analyzed for components. Carbon manganese, medium carbon manganese and electrolytic manganese are added to the steel liquid according to the composition ratio to adjust the Mn element content in the steel liquid. C powder and Si powder are added to the steel liquid for reduction. Before tapping, part of the slag is removed and CaO slag is added for homogenization.

[0097] Before tapping, keep as much slag as possible, and the slag added during tapping flows into the ladle along with the molten steel. Before tapping, the molten steel should be oxygenated, and C powder or C balls should be added for deoxidation according to the oxygen activity, and the oxygen activity in the molten steel should be controlled to be ≤1000ppm. Add 2.5kg / t of SiAl into the ladle.

[0098] The steel tapping temperature is 1610℃.

[0099] S15. Refining is performed in a LF furnace, and the final composition of the molten steel is determined in the LF furnace.

[0100] Add deoxidizer and CaO slag into the ladle. Add CaO slag into the ladle in 3 batches in a 40-ton ladle, with 100 kg added to each batch. When adding CaO slag, ensure that the slag has good fluidity and the slag color turns white. Use SiFe powder or C powder to deoxidize the slag surface in the ladle.

[0101] 130kg of silica is added to the ladle, and high-purity argon is introduced for stirring and refining. The Ar gas flow rate is controlled in principle so that the molten steel does not turn over the slag surface. After stirring and slagging for 5 minutes, 80 meters of Ca wire is fed, and the final composition of the molten steel is adjusted. The calming time is not less than 3 minutes, and carbonized rice is added for heat preservation, and the ladle is poured.

[0102] The liquidus temperature of molten steel is 1380℃. The pouring temperature of the first ladle is 1445℃-1450℃, and the pouring temperature of the follower ladle is 1442℃-1447℃. If it is a cold ladle or a standby ladle, the ladle temperature needs to be increased by 5℃.

[0103] S2, continuously casting the solution to obtain a 150 mm thick ingot, and cutting the ingot to a predetermined length to obtain a slab.

[0104] The size of the immersion nozzle is 80mm*40mm, the inclination angle is 15°, and the immersion depth is 95mm.

[0105] The water volume of the crystallizer is 2750L / min on the wide side and 250L / min on the narrow side. The taper of the crystallizer is 1.25, and the width shrinkage of the ingot is 1.027%.

[0106] The temperature of the continuous casting tundish is ≥1000℃ and the baking time is not less than 4 hours.

[0107] The temperature of the molten steel in the continuous casting tundish is 1410°C-1420°C. The pulling speed is 0.96m / min-1.0m / min, and the emergence time is 120 seconds.

[0108] The ingot is cooled to 400°C and cut to a fixed length to obtain a slab, which is then hot-transferred to a heating furnace for hot rolling.

[0109] S3, placing the slab into a heating furnace for heating, and hot rolling the slab to obtain a rolled plate.

[0110] The temperature of the preheating section of the heating furnace is 600°C, the temperature of the heating section is 1150°C, and the temperature of the soaking section is 1150°C. The preheating time of the slab in the preheating section is 30 minutes, and the heating time of the slab in the heating furnace is 4 hours.

[0111] Before hot rolling, the slab needs to be dephosphorized. Precise dephosphorization is performed in the first few passes of the rough rolling stage to ensure that the slab surface is completely dephosphorized and the iron oxide scale is removed. In the finishing rolling stage, according to the actual steel temperature and the condition of the surface iron oxide scale, 1-2 more dephosphorizations are appropriately added to ensure that the iron oxide scale is completely removed. The dephosphorization water pressure is not less than 15MPa.

[0112] The rolling process includes flattening by the roughing mill, widening by the roughing mill, and lengthening by the finishing mill.

[0113] Adjust the direction of the billet to ensure that the first small end enters the rolling mill. According to the thickness of the small end of the billet and the length of the intermediate billet after flattening, flattening rolling is carried out on the basis of ensuring that the length of the intermediate billet is ≤2400mm.

[0114] According to the size of the billet after flattening, calculate the widening position of the small end width, and take the widening position of the small end width as the order width.

[0115] The second rolling temperature is not less than 1000℃, there is no temperature control in the middle, and the final rolling temperature is 820℃.

[0116] The thickness of the rolled plate after finish rolling is 10 mm.

[0117] S4. Perform solution water toughening heat treatment on the rolled plate.

[0118] The heat treatment temperature of the solution heat treatment is 1050℃, the holding time is 15min, and the cooling time is 40S.

[0119] S5. Finish the rolled plate and obtain the wear-resistant steel plate after shearing.

[0120] Example 3

[0121] The preparation method of wear-resistant high manganese steel comprises the following steps: S1. Weigh the raw materials according to the component ratio, and melt the raw materials to obtain a solution.

[0122] Smelting includes the following steps: S11. Put the weighed raw materials into the EAF furnace for smelting. P in the molten metal is ≤ 0.04%.

[0123] S12. After 60 minutes of power-on, oxygen is blown into the EAF furnace for fluxing.

[0124] S13. After complete melting, the mass percentage of C in the molten steel is 0.05%-0.1%, the slag P≤0.005%, and the slag temperature is not less than 1630℃. Clear the oxide slag, add CaO slag to the solution, and the addition amount of CaO slag is 0.5%-1.5%. After the slag is homogenized, add Al powder, C powder and Si powder to reduce and make white slag.

[0125] S14. After the slag changes color, the steel liquid is analyzed for components. Carbon manganese, medium carbon manganese and electrolytic manganese are added to the steel liquid according to the composition ratio to adjust the Mn element content in the steel liquid. C powder and Si powder are added to the steel liquid for reduction. Before tapping, part of the slag is removed and CaO slag is added for homogenization.

[0126] Before tapping, keep as much slag as possible, and the slag added during tapping flows into the ladle along with the molten steel. Before tapping, the molten steel should be oxygenated, and C powder or C balls should be added for deoxidation according to the oxygen activity, and the oxygen activity in the molten steel should be controlled to be ≤1000ppm. Add 2.5kg / t of SiAl into the ladle.

[0127] The steel tapping temperature is 1640℃.

[0128] S15. Refining is performed in a LF furnace, and the final composition of the molten steel is determined in the LF furnace.

[0129] Add deoxidizer and CaO slag into the ladle. Add CaO slag into the ladle in 3 batches in a 40-ton ladle, with 100 kg added to each batch. When adding CaO slag, ensure that the slag has good fluidity and the slag color turns white. Use SiFe powder or C powder to deoxidize the slag surface in the ladle.

[0130] 130kg of silica is added to the ladle, and high-purity argon is introduced for stirring and refining. The Ar gas flow rate is controlled in principle so that the molten steel does not turn over the slag surface. After stirring and slagging for 5 minutes, 80 meters of Ca wire is fed, and the final composition of the molten steel is adjusted. The calming time is not less than 3 minutes, and carbonized rice is added for heat preservation, and the ladle is poured.

[0131] The liquidus temperature of molten steel is 1380℃. The pouring temperature of the first ladle is 1445℃-1450℃, and the pouring temperature of the follower ladle is 1442℃-1447℃. If it is a cold ladle or a standby ladle, the ladle temperature needs to be increased by 5℃.

[0132] S2, continuously casting the solution to obtain a 200 mm thick ingot, and cutting the ingot to a predetermined length to obtain a slab.

[0133] The size of the immersion nozzle is 80mm*40mm, the inclination angle is 15°, and the immersion depth is 95mm.

[0134] The water volume of the crystallizer is 2750L / min on the wide side and 250L / min on the narrow side. The taper of the crystallizer is 1.25, and the width shrinkage of the ingot is 1.027%.

[0135] The temperature of the continuous casting tundish is ≥1000℃ and the baking time is not less than 4 hours.

[0136] The temperature of the molten steel in the continuous casting tundish is 1427-1432°C. The pulling speed is 0.44m / min-0.4m / min, and the emergence time is 140 seconds.

[0137] The ingot is cooled to 400°C and cut to a fixed length to obtain a slab, which is then hot-transferred to a heating furnace for hot rolling.

[0138] S3, placing the slab into a heating furnace for heating, and hot rolling the slab to obtain a rolled plate.

[0139] The temperature of the preheating section of the heating furnace is 700°C, the temperature of the heating section is 1200°C, and the temperature of the soaking section is 1200°C. The preheating time of the slab in the preheating section is 50 minutes, and the heating time of the slab in the heating furnace is 5 hours.

[0140] Before hot rolling, the slab needs to be dephosphorized. Precise dephosphorization is performed in the first few passes of the rough rolling stage to ensure that the slab surface is completely dephosphorized and the iron oxide scale is removed. In the finishing rolling stage, according to the actual steel temperature and the condition of the surface iron oxide scale, 1-2 more dephosphorizations are appropriately added to ensure that the iron oxide scale is completely removed. The dephosphorization water pressure is not less than 15MPa.

[0141] The rolling process includes flattening by the roughing mill, widening by the roughing mill, and lengthening by the finishing mill.

[0142] Adjust the direction of the billet to ensure that the first small end enters the rolling mill. According to the thickness of the small end of the billet and the length of the intermediate billet after flattening, flattening rolling is carried out on the basis of ensuring that the length of the intermediate billet is ≤2400mm.

[0143] According to the size of the billet after flattening, calculate the widening position of the small end width, and take the widening position of the small end width as the order width.

[0144] The second rolling temperature is not less than 1000℃, there is no temperature control in the middle, and the final rolling temperature is 840℃.

[0145] The thickness of the rolled plate after finish rolling is 20 mm.

[0146] S4. Perform solution water toughening heat treatment on the rolled plate.

[0147] The heat treatment temperature of the solution heat treatment is 1050℃, the holding time is 30min, and the cooling time is 30S.

[0148] S5. Finish the rolled plate and obtain the wear-resistant steel plate after shearing.

[0149] Example 4

[0150] The preparation method of wear-resistant high manganese steel comprises the following steps: S1. Weigh the raw materials according to the component ratio, and melt the raw materials to obtain a solution.

[0151] Smelting includes the following steps: S11. Put the weighed raw materials into the EAF furnace for smelting. P in the molten metal is ≤ 0.04%.

[0152] S12. After 60 minutes of power-on, oxygen is blown into the EAF furnace for fluxing.

[0153] S13. After complete melting, the mass percentage of C in the molten steel is 0.05%-0.1%, the slag P≤0.005%, and the slag temperature is not less than 1630℃. Clear the oxide slag, add CaO slag to the solution, and the addition amount of CaO slag is 0.5%-1.5%. After the slag is homogenized, add Al powder, C powder and Si powder to reduce and make white slag.

[0154] S14. After the slag changes color, the steel liquid is analyzed for components. Carbon manganese, medium carbon manganese and electrolytic manganese are added to the steel liquid according to the composition ratio to adjust the Mn element content in the steel liquid. C powder and Si powder are added to the steel liquid for reduction. Before tapping, part of the slag is removed and CaO slag is added for homogenization.

[0155] Before tapping, keep as much slag as possible, and the slag added during tapping flows into the ladle along with the molten steel. Before tapping, the molten steel should be oxygenated, and C powder or C balls should be added for deoxidation according to the oxygen activity, and the oxygen activity in the molten steel should be controlled to be ≤1000ppm. Add 2.5kg / t of SiAl into the ladle.

[0156] The steel tapping temperature is 1640℃.

[0157] S15. Refining is performed in a LF furnace, and the final composition of the molten steel is determined in the LF furnace.

[0158] Add deoxidizer and CaO slag into the ladle. Add CaO slag into the ladle in 3 batches in a 40-ton ladle, with 100 kg added to each batch. When adding CaO slag, ensure that the slag has good fluidity and the slag color turns white. Use SiFe powder or C powder to deoxidize the slag surface in the ladle.

[0159] 130kg of silica is added to the ladle, and high-purity argon is introduced for stirring and refining. The Ar gas flow rate is controlled in principle so that the molten steel does not turn over the slag surface. After stirring and slagging for 5 minutes, 80 meters of Ca wire is fed, and the final composition of the molten steel is adjusted. The calming time is not less than 3 minutes, and carbonized rice is added for heat preservation, and the ladle is poured.

[0160] The liquidus temperature of molten steel is 1380℃. The pouring temperature of the first ladle is 1445℃-1450℃, and the pouring temperature of the follower ladle is 1442℃-1447℃. If it is a cold ladle or a standby ladle, the ladle temperature needs to be increased by 5℃.

[0161] S2, continuously casting the solution to obtain a 200 mm thick ingot, and cutting the ingot to a predetermined length to obtain a slab.

[0162] The size of the immersion nozzle is 80mm*40mm, the inclination angle is 15°, and the immersion depth is 95mm.

[0163] The water volume of the crystallizer is 2750L / min on the wide side and 250L / min on the narrow side. The taper of the crystallizer is 1.25, and the width shrinkage of the ingot is 1.027%.

[0164] The temperature of the continuous casting tundish is ≥1000℃ and the baking time is not less than 4 hours.

[0165] The temperature of the molten steel in the continuous casting tundish is 1409°C. The pulling speed is 0.6m / min-0.55m / min, and the emergence time is 130 seconds.

[0166] The ingot is cooled to 400°C and cut to a fixed length to obtain a slab, which is then hot-transferred to a heating furnace for hot rolling.

[0167] S3, placing the slab into a heating furnace for heating, and hot rolling the slab to obtain a rolled plate.

[0168] The temperature of the preheating section of the heating furnace is 700°C, the temperature of the heating section is 1200°C, and the temperature of the soaking section is 1200°C. The preheating time of the slab in the preheating section is 50 minutes, and the heating time of the slab in the heating furnace is 5 hours.

[0169] Before hot rolling, the slab needs to be dephosphorized. Precise dephosphorization is performed in the first few passes of the rough rolling stage to ensure that the slab surface is completely dephosphorized and the iron oxide scale is removed. In the finishing rolling stage, according to the actual steel temperature and the condition of the surface iron oxide scale, 1-2 more dephosphorizations are appropriately added to ensure that the iron oxide scale is completely removed. The dephosphorization water pressure is not less than 15MPa.

[0170] The rolling process includes flattening by the roughing mill, widening by the roughing mill, and lengthening by the finishing mill.

[0171] Adjust the direction of the billet to ensure that the first small end enters the rolling mill. According to the thickness of the small end of the billet and the length of the intermediate billet after flattening, flattening rolling is carried out on the basis of ensuring that the length of the intermediate billet is ≤2400mm.

[0172] According to the size of the billet after flattening, calculate the widening position of the small end width, and take the widening position of the small end width as the order width.

[0173] The second rolling temperature is not less than 1000℃, there is no temperature control in the middle, and the final rolling temperature is 840℃.

[0174] The thickness of the rolled plate after finish rolling is 20 mm.

[0175] S4. Perform solution water toughening heat treatment on the rolled plate.

[0176] The heat treatment temperature of the solution heat treatment is 1050℃, the holding time is 30min, and the cooling time is 30S.

[0177] S5. Finish the rolled plate and obtain the wear-resistant steel plate after shearing.

[0178] Comparative Example 1

[0179] The preparation method of this comparative example is the same as that of Example 2, except that the content of Mn element in this comparative example is different from that in Example 2.

[0180] Comparative Example 2

[0181] The preparation method of this comparative example is the same as that of Example 2, except that the content of element C in this comparative example is different from that in Example 2.

[0182] The composition of high manganese steel in Examples 1-4 and Comparative Examples 1-2 is shown in Table 3.

[0183] Table 3 Composition of high manganese steel in Examples 1-4 and Comparative Examples 1-2

[0184] GB / T228 was used to test the room temperature tensile properties of the steel plate at the head or tail of the heat-treated rolled plate, and GB / T231.1 was used to test the hardness at any position of the heat-treated rolled plate. The mechanical properties of the high manganese steel rolled plates in Examples 1-4 and Comparative Examples 1-2 are shown in Table 4.

[0185] Table 4 Mechanical properties of high manganese steel rolled plates in Examples 1-4 and Comparative Examples 1-2

[0186] Therefore, the wear-resistant high manganese steel and the preparation method thereof described in the present invention can solve the problems of low tensile strength, poor comprehensive performance and complex manufacturing process of the existing high manganese steel.

[0187] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A wear-resistant high manganese steel, characterized in that: It includes the following components in mass percentage: C 0.9%-1.1%, Si 0.2%-0.6%, Mn 17%-19%, Cr 1.5%-2.5%, P ≤0.003%, S ≤0.003%, Al ≤0.003%, and the balance Fe.

2. The wear-resistant high manganese steel according to claim 1, characterized in that: It includes the following components in mass percentage: C 1.0%, Si 0.3%, Mn 18%, Cr 2%, P ≤0.002%, S ≤0.003%, Al ≤0.003%, rare earth 0.1%, and the balance Fe.

3. The method for preparing wear-resistant high manganese steel according to claim 1 or 2, characterized in that: The following steps are involved: S1. Weigh the raw materials according to the component ratio, and melt the raw materials to obtain a solution; S2, continuously casting the solution to obtain a casting billet with a thickness of 150 mm to 300 mm, and cutting the casting billet to a fixed length to obtain a slab; S3, placing the slab into a heating furnace for heating, and hot rolling the slab to obtain a rolled plate with a thickness of 2 mm to 50 mm; S4, performing solution water toughening heat treatment on the rolled plate; S5. Finish the rolled plate and obtain the wear-resistant steel plate after shearing.

4. The method for preparing wear-resistant high manganese steel according to claim 3, characterized in that: In S1, smelting includes the following steps: S11, placing the weighed raw materials into an EAF furnace for smelting; S12, after 60 minutes of power on, blowing oxygen into the EAF furnace for fluxing; S13, after the melting is complete, the mass percentage of C in the molten steel is 0.05%-0.1%; remove the oxide slag, add CaO slag to the solution, add Al powder, C powder and Si powder to reduce the slag after it is evenly mixed; S14, analyzing the composition of the molten steel, adjusting the Mn element content in the molten steel according to the composition ratio; removing the slag before tapping, adding CaO slag material for homogenization, and the oxygen activity in the molten steel is ≤1000ppm; S15. Refining is carried out in a LF furnace. Deoxidizer and CaO slag are added to the ladle. Silica is added to the ladle, and high-purity argon is introduced for refining. After stirring the slag for 3min-5min, the Ca wire is fed, the composition of the molten steel is adjusted, the calming time is not less than 3min, carbonized rice is added for heat preservation, and the ladle is poured.

5. The method for preparing wear-resistant high manganese steel according to claim 4, characterized in that: In the S13, the addition amount of CaO slag is 0.5%-1.5%.

6. The method for preparing wear-resistant high manganese steel according to claim 4, characterized in that: In the S14, the steel tapping temperature is 1600°C-1650°C.

7. The method for preparing wear-resistant high manganese steel according to claim 4, characterized in that: In S15, the pouring temperature of the first ladle is 1445°C-1450°C, and the pouring temperature of the following ladle is 1442°C-1447°C.

8. The method for preparing wear-resistant high manganese steel according to claim 3, characterized in that: In S2, the temperature of the molten steel in the continuous casting tundish is 1410°C-1435°C, the pulling speed is 0.4m / min-1.0m / min, and the emergence time is 120 seconds-150 seconds.

9. The method for preparing wear-resistant high manganese steel according to claim 3, characterized in that: In S3, the temperature of the preheating section of the heating furnace is 600°C-800°C, the temperature of the heating section is 1150°C-1200°C, the temperature of the soaking section is 1150°C-1200°C, the preheating time of the slab in the preheating section is not less than 30 minutes, and the heating time of the slab in the heating furnace is not less than 4 hours; the second opening temperature of hot rolling is not less than 1000°C, and the final rolling temperature is not less than 820°C.

10. The method for preparing wear-resistant high manganese steel according to claim 3, characterized in that: In the S4, the heat treatment temperature of the solution heat treatment is 1000°C-1100°C, the heat preservation is 1.5 minutes for every 1mm thickness, and the cooling is water cooling to room temperature within 1 minute.

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