High-carbon high-manganese frog steel and smelting process thereof

Abstract

The invention relates to high-carbon high-manganese frog steel and a smelting process thereof, the elongation and impact absorption energy of the high-carbon high-manganese frog steel can meet the performance use requirements of the frog steel, the high-carbon high-manganese frog steel comprises the following chemical components in percentage by weight: 1.00%-1.30% of C, 0.30%-0.80% of Si, 12.0%-14.0% of Mn, less than or equal to 0.030% of P, less than or equal to 0.015% of S, less than or equal to 0.15% of Cu and the balance of ferrum, and the production process of the steel adopts an electric furnace to melt waste steel, melting the high-manganese alloy and the stub bar in an induction furnace, carrying out ladle argon blowing refining, vacuum degassing and casting to form a steel ingot, carrying out hot feeding or air cooling on the steel ingot, and then feeding the steel ingot to a forging station for forging to form a frog forge piece; the components, the gas content and the normal-temperature impact energy of the steel for the high-carbon and high-manganese frog product produced by the process all meet the requirements, and the service life meets the actual requirements.

Description

Technical Field

[0001] The invention belongs to the technical field of steelmaking process, and relates to a high-carbon high-manganese frog steel and a smelting process thereof, wherein both the elongation and the impact absorption energy can meet the performance requirements of the frog steel. Background Art

[0002] At present, the use of high-carbon and high-manganese steel frog products in the market is very large. In the past, they were all produced by cast steel, and the tonnage of goods used was not high; especially the elongation and impact absorption energy could not meet the performance requirements of frog steel. Through research, it was found that forged high-carbon and high-manganese steel frog products can replace the existing cast high-manganese steel frog products, so as to meet the performance requirements of steel frog products that meet the elongation and impact absorption energy. At the same time, through the development of new high-carbon and high-manganese frog steel products, the demand for railway frog products will gradually be formed, which can meet the current needs of railway frog products for elongation and impact absorption energy performance. In the study of high-carbon and high-manganese frog steel products, it was found that in order to further improve the purity of the molten steel during the smelting process of high-carbon and high-manganese steel, vacuum degassing is required. In the vacuum degassing process, more manganese elements evaporate. Since this steel belongs to austenitic steel, the gas requirements are not strict. In order to reduce the loss of manganese elements, it can be considered to appropriately increase the vacuum degree during the vacuum degassing process to reduce the loss of manganese elements. Summary of the invention

[0003] The object of the present invention is to overcome the shortcomings of the prior art and provide a high carbon and high manganese frog steel and a smelting process thereof, which is produced by using electric furnace smelting + vacuum refining and casting into steel ingots to manufacture high carbon and high manganese frog steel. The frog product steel smelted by the process has [P]≤0.020%, [S]≤0.003%, [Mn]12.5-13.0%, elongation (A)≥40 / %, and impact absorption energy KU2 (normal temperature)≥150 / J, meeting the use requirements of frog steel.

[0004] The object of the present invention is achieved in that: A high-carbon and high-manganese frog steel comprises the following chemical components in weight percentage: C1.00%-1.30%, Si0.30%-0.80%, Mn12.0%-14.0%, P≤0.030%, S≤0.015%, Cu≤0.15%, and the balance is iron.

[0005] A high-carbon and high-manganese frog steel, wherein the high-carbon and high-manganese frog steel comprises the following chemical components as the best choice according to weight percentage: C 1.00%-1.20%, Si 0.40%-0.80%, Mn 12.5%-13.5%, Cr≤0.20%, Mo≤0.20%, V≤0.10%, P≤0.020%, S≤0.005%, Cu≤0.15%, and the balance is iron.

[0006] A smelting process of a high-carbon and high-manganese frog steel comprises the following steps: melting scrap steel in an electric furnace, refining with argon blowing in a ladle, vacuum degassing, casting into steel ingots, and hot or air-cooling the steel ingots before sending them to a forging section for forging into frog forgings; specifically, the following steps are included: Step 1), batching: the furnace charge includes 40-60% high-quality scrap steel or high-quality steel scraps, 20-40% pig iron, and 30-50% return steel head according to weight percentage. Miscellaneous scrap steel and oily steel scraps are not allowed; according to the batching situation, 20.0-30.0kg / t of lime and 5.0-10.0kg / t of carburizer are added into the furnace to control the sum of the five harmful elements As+Sn+Pb+Sb+Bi in the finished frog material to be ≤0.020%; Step 2), electric arc furnace: Electric furnace tapping control [C] ≥ 0.30%, [P] ≤ 0.005%, tapping temperature ≥ 1640 ° C, lime 4.0 ~ 6.0 kg / t, aluminum block 2.0 ~ 4.0 kg / t, high manganese 30.0 ~ 50.0 kg / t, ferrosilicon 2.0 ~ 5.0 kg / t are added with the steel flow during the tapping process, and the amount of steel left in the electric furnace is ≥ 5 tons to ensure that there is no slag when tapping; Step 3), induction furnace: the charge includes 40-60% high manganese steel or carbon steel head, 20-40% high manganese or medium manganese alloy, and 10-40% steel scraps according to weight percentage. The charge is required to be clean and oil-free. The composition is confirmed by spectrum before use to ensure that the composition of the charge head and steel scraps entering the furnace meets the use requirements and that the alloy elements after adding steel do not exceed the upper limit of the process requirements; the induction furnace equipment and lining meet the smelting requirements, the charging should be tight at the bottom and loose at the top, the direction of the charge should be consistent with the longitudinal direction of the furnace, and long materials are not allowed to be placed horizontally or obliquely in the furnace. The charge should be substantial and full. During the smelting process, the raw materials should be pried or knocked with dry wooden sticks to prevent the raw materials from bridging and generating high temperature. After the charge of the induction furnace is melted, the temperature is 1570-1600℃ for sampling. Before tapping, calcium silicon powder or aluminum insertion 1.0-2.0kg / t is added for deoxidation at a temperature of 1580-1620℃. After checking the composition, the electric furnace is used for tapping; Step 4), ladle furnace: After the ladle furnace is in place, argon is first connected for stirring, heating and refining, and the temperature is adjusted to ≥1550℃. According to the amount of slag, 4-6.0kg / t of lime and 1-2.0kg / t of fluorite are added. After slag is slag-forming, 1-2.0kg / t of calcium carbide and 2.0-4.0kg / t of carbon powder or ferrosilicon powder deoxidizer are added. The slag is electrified, and the temperature is measured, sampled, and the chemical composition is adjusted after the slag is white. During refining, 1.0-2.0kg / t of carbon powder and 1.0-2.0kg / t of calcium silicon powder or ferrosilicon powder are used in small batches and multiple batches for deoxidation and a reducing atmosphere is maintained to ensure uniform composition temperature and white slag for ≥20 minutes. The composition is adjusted according to the target value and the white slag is ensured to be hung; Step 5), vacuum degassing: temperature 1550 ~ 1570 ℃ from the LF furnace bag into the vacuum tank, adjust the argon flow rate before pumping, ensure that the molten steel and slag surface fluctuate slightly, and do not adjust the argon flow rate during the pumping process. Keep at 200mbar for ≥ 20 minutes before breaking the air. After breaking the air, determine hydrogen and oxygen online to control [H] ≤ 3.0ppm, [O] ≤ 5.0ppm, take a glass tube sample to analyze the [N] content, and control [N] ≤ 50ppm; control residual [Al] ≤ 0.020%; Step 6), carefully select the ingot mold before production, preferably the ingot mold with good inner wall quality, and the use temperature ≥50℃; the flow steel bricks in the soup channel system should be dried more, and mullite flow steel bricks should be used. Carefully select them before use to ensure that the pouring system is clean and dry; the calming time is ≥10 minutes, and argon is filled in the mold and argon is used to protect the pouring before pouring; pouring temperature: 1440~1460℃; control the steel flow to enter the mold smoothly, and scattered flow pouring is not allowed. The pouring time is implemented according to the upper and lower limits, and the riser part is fully poured; medium and low carbon mold casting slag is hung in the mold, and the insufficient part is added after pouring; after adding the heating agent, carbonized rice husk is added in time to ensure the shrinkage compensation effect; the ingot is hot transported or air cooled after demoulding, and the surface is cleaned after air cooling.

[0007] The beneficial effects of the present invention are as follows: The present invention adds 20-40% pig iron and 30-50% return steel head during batching, controls As+Sn+Pb+Sb+Bi in the raw materials to be ≤0.020%, adds lime, aluminum block, high manganese and ferrosilicon with the steel flow during the steel tapping process of the electric arc furnace; melts the high manganese alloy and the head in the induction furnace, refines with argon blowing in the ladle furnace, heats up, deoxidizes, desulfurizes, adjusts the alloy composition, vacuum degasses, and casts into steel ingots. The steel ingots are sent to the forging company after hot or air cooling to be forged into frog forgings. The finished product inspection shows that the frog product steel [P] is 0.018%, [S] is 0.002%, [Mn] is 12.90%, the elongation (A) is ≥40 / %, and the impact absorption energy KU2 (normal temperature) is ≥150 / J, which meets the use requirements of customers. DETAILED DESCRIPTION

[0008] A high-carbon and high-manganese frog steel comprises the following chemical components in weight percentage: C1.00%-1.30%, Si0.30%-0.80%, Mn12.0%-14.0%, P≤0.030%, S≤0.015%, Cu≤0.15%, and the balance is iron.

[0009] A high-carbon and high-manganese frog steel, the following chemical components are optimally selected according to weight percentage: C1.00%-1.20%, Si0.40%-0.80%, Mn12.5%-13.5%, Cr≤0.20%, Mo≤0.20%, V≤0.10%, P≤0.020%, S≤0.005%, Cu≤0.15%, and the balance is iron.

[0010] A smelting process of high-carbon and high-manganese frog steel, which adopts electric furnace to melt scrap steel, ladle argon blowing refining, vacuum degassing, casting into steel ingots, hot or air-cooled steel ingots and then sent to forging section for forging into frog forgings; specifically includes the following steps: Step 1), batching: the furnace charge includes 40-60% high-quality scrap steel or high-quality steel scraps, 20-40% pig iron, and 30-50% return steel head according to weight percentage. Miscellaneous scrap steel and oily steel scraps are not allowed; according to the batching situation, 20.0-30.0kg / t of lime and 5.0-10.0kg / t of carburizer are added into the furnace to control the sum of the five harmful elements As+Sn+Pb+Sb+Bi in the finished frog material to be ≤0.020%; Step 2), electric arc furnace: Electric furnace tapping control [C] ≥ 0.30%, [P] ≤ 0.005%, tapping temperature ≥ 1640 ° C, lime 4.0 ~ 6.0 kg / t, aluminum block 2.0 ~ 4.0 kg / t, high manganese 30.0 ~ 50.0 kg / t, ferrosilicon 2.0 ~ 5.0 kg / t are added with the steel flow during the tapping process, and the amount of steel left in the electric furnace is ≥ 5 tons to ensure that there is no slag when tapping; Step 3), induction furnace: the charge includes 40-60% high manganese steel or carbon steel head, 20-40% high manganese or medium manganese alloy, and 10-40% steel scraps according to weight percentage. The charge is required to be clean and oil-free. The composition is confirmed by spectrum before use to ensure that the composition of the charge head and steel scraps entering the furnace meets the use requirements and that the alloy elements after adding steel do not exceed the upper limit of the process requirements; the induction furnace equipment and lining meet the smelting requirements, the charging should be tight at the bottom and loose at the top, the direction of the charge should be consistent with the longitudinal direction of the furnace, and long materials are not allowed to be placed horizontally or obliquely in the furnace. The charge should be substantial and full. During the smelting process, the raw materials should be pried or knocked with dry wooden sticks to prevent the raw materials from bridging and generating high temperature. After the charge of the induction furnace is melted, the temperature is 1570-1600℃ for sampling. Before tapping, calcium silicon powder or aluminum insertion 1.0-2.0kg / t is added for deoxidation at a temperature of 1580-1620℃. After checking the composition, the electric furnace is used for tapping; Step 4), ladle furnace: After the ladle furnace is in place, argon is first connected for stirring, heating and refining, and the temperature is adjusted to ≥1550℃. According to the amount of slag, 4-6.0kg / t of lime and 1-2.0kg / t of fluorite are added. After slag is slag-forming, 1-2.0kg / t of calcium carbide and 2.0-4.0kg / t of carbon powder or ferrosilicon powder deoxidizer are added. The slag is electrified, and the temperature is measured, sampled, and the chemical composition is adjusted after the slag is white. During refining, 1.0-2.0kg / t of carbon powder and 1.0-2.0kg / t of calcium silicon powder or ferrosilicon powder are used in small batches and multiple batches for deoxidation and a reducing atmosphere is maintained to ensure uniform composition temperature and white slag for ≥20 minutes. The composition is adjusted according to the target value and the white slag is ensured to be hung; Step 5), vacuum degassing: temperature 1550 ~ 1570 ℃ from the LF furnace bag into the vacuum tank, adjust the argon flow rate before pumping, ensure that the molten steel and slag surface fluctuate slightly, and do not adjust the argon flow rate during the pumping process. Keep at 200mbar for ≥ 20 minutes before breaking the air. After breaking the air, determine hydrogen and oxygen online to control [H] ≤ 3.0ppm, [O] ≤ 5.0ppm, take a glass tube sample to analyze the [N] content, and control [N] ≤ 50ppm; control residual [Al] ≤ 0.020%; (Target 0.010-0.020%); Step 6), carefully select the ingot mold before production, preferably the ingot mold with good inner wall quality, and the use temperature ≥50℃; the flow steel bricks in the soup channel system should be dried more, and mullite flow steel bricks should be used. Carefully select them before use to ensure that the pouring system is clean and dry; the calming time is ≥10 minutes, and argon is filled in the mold and argon is used to protect the pouring before pouring; pouring temperature: 1440~1460℃; control the steel flow to enter the mold smoothly, and scattered flow pouring is not allowed. The pouring time is implemented according to the upper and lower limits, and the riser part is fully poured; medium and low carbon mold casting slag is hung in the mold, and the insufficient part is added after pouring; after adding the heating agent, carbonized rice husk is added in time to ensure the shrinkage compensation effect; the ingot is hot transported or air cooled after demoulding, and the surface is cleaned after air cooling.

[0011] Example 1: The chemical composition and mechanical properties of the high-carbon and high-manganese steel for frog products forged by vacuum refined steel ingots are shown in the table below; the test results show that the high-carbon and high-manganese steel for frog products produced by the process of the present invention has a composition, gas content, and (room temperature) impact energy that meet the requirements, and the service life meets the actual requirements.

[0012] Appendix: The chemical composition of high carbon and high manganese frog product steel is as follows: Table 1 Chemical composition (m%) element Target ingredients This embodiment C 1.00-1.30 1.08 Si 0.30-0.80 0.50 Mn 12.0-14.0 12.90 P ≤0.030 0.018 S ≤0.015 0.002 Cr ≤0.20 0.13 Mo ≤0.20 0.10 V ≤0.10 0.03 Cu ≤0.20 0.06 As ≤0.010 0.007 Sn ≤0.005 0.004 Pb ≤0.010 0.002 Sb ≤0.010 0.001 Bi ≤0.005 0.001 Appendix: High carbon and high manganese frog steel gas is as follows Table 2: Table 2 Gas (ppm) element Target This embodiment [H] ≤5.0 2.8 [O] ≤20 13 [N] ≤80 68 Appendix: The mechanical properties of high carbon and high manganese frog steel are shown in Table 3: Table 3 Mechanical properties element Target Requirements This embodiment Rp0.2 ≥390 (Mpa) 430 (Mpa) Rm ≥900 (Mpa) 1230 (Mpa) A ≥40% 45% (Normal temperature) KU2 ≥150（J） 170（J） .

Claims

1. A high carbon and high manganese frog steel, characterized in that: The high carbon and high manganese frog steel comprises the following chemical components in weight percentage: C 1.00%-1.30%, Si 0.30%-0.80%, Mn 12.0%-14.0%, P≤0.030%, S≤0.015%, Cu≤0.15%, and the balance is iron.

2. A high carbon and high manganese frog steel, characterized in that: The high carbon and high manganese frog steel preferably includes the following chemical components in weight percentage: C 1.00% to 1.20%, Si 0.40% to 0.80%, Mn 12.5% ​​to 13.5%, Cr≤0.20%, Mo≤0.20%, V ≤0.10%, P≤0.020%, S≤0.005%, Cu≤0.15%, and the balance is iron.

3. A smelting process for a high carbon and high manganese frog steel as claimed in claim 1 or 2, characterized in that: The smelting process of the high carbon and high manganese frog steel comprises the following steps: melting scrap steel in an electric furnace, refining with argon blowing in a ladle, vacuum degassing, casting into steel ingots, and hot or air cooling the steel ingots before sending them to a forging section for forging into frog forgings; the specific steps include: Step 1), batching: the furnace charge includes 40-60% high-quality scrap steel or high-quality steel scraps, 20-40% pig iron, and 30-50% return steel head according to weight percentage. Miscellaneous scrap steel and oily steel scraps are not allowed; according to the batching situation, 20.0-30.0kg / t of lime and 5.0-10.0kg / t of carburizer are added into the furnace to control the sum of the five harmful elements As+Sn+Pb+Sb+Bi in the finished frog material to be ≤0.020%; Step 2), electric arc furnace: Electric furnace tapping control [C] ≥ 0.30%, [P] ≤ 0.005%, tapping temperature ≥ 1640 ° C, lime 4.0 ~ 6.0 kg / t, aluminum block 2.0 ~ 4.0 kg / t, high manganese 30.0 ~ 50.0 kg / t, ferrosilicon 2.0 ~ 5.0 kg / t are added with the steel flow during the tapping process, and the amount of steel left in the electric furnace is ≥ 5 tons to ensure that there is no slag when tapping; Step 3), induction furnace: the charge includes 40-60% high manganese steel or carbon steel head, 20-40% high manganese or medium manganese alloy, and 10-40% steel scraps by weight. The charge is required to be clean and oil-free. The composition is confirmed by spectrum before use to ensure that the composition of the charge and steel scraps meets the use requirements and that the alloy elements after adding steel do not exceed the upper limit of the process requirements; The induction furnace equipment and lining meet the smelting requirements. The charging should be tight at the bottom and loose at the top. The direction of the charging should be consistent with the longitudinal direction of the furnace. Long materials are not allowed to be placed horizontally or diagonally in the furnace. The charging should be sufficient and full. During the smelting process, the raw materials should be pried or knocked with dry wooden sticks to prevent the raw materials from bridging and generating high temperature. After the charging of the induction furnace is melted, the temperature is 1570-1600℃ for sampling. Before tapping, add calcium silicon powder or insert aluminum 1.0-2.0kg / t for deoxidation, the temperature is 1580-1620℃, and after checking the composition, cooperate with the electric furnace for tapping; Step 4), ladle furnace: After the ladle furnace is in place, argon is first connected for stirring, heating and refining, and the temperature is adjusted to ≥1550℃. According to the amount of slag, 4-6.0kg / t of lime and 1-2.0kg / t of fluorite are added. After slag is slag-forming, 1-2.0kg / t of calcium carbide and 2.0-4.0kg / t of carbon powder or ferrosilicon powder deoxidizer are added. The slag is electrified, and the temperature is measured, sampled, and the chemical composition is adjusted after the slag is white. During refining, 1.0-2.0kg / t of carbon powder and 1.0-2.0kg / t of calcium silicon powder or ferrosilicon powder are used in small batches and multiple batches for deoxidation and a reducing atmosphere is maintained to ensure uniform composition temperature and white slag for ≥20 minutes. The composition is adjusted according to the target value and the white slag is ensured to be hung; Step 5), vacuum degassing: temperature 1550 ~ 1570 ℃ from the LF furnace bag into the vacuum tank, adjust the argon flow rate before pumping, ensure that the molten steel and slag surface fluctuate slightly, and do not adjust the argon flow rate during the pumping process. Keep at 200mbar for ≥ 20 minutes before breaking the air. After breaking the air, determine hydrogen and oxygen online to control [H] ≤ 3.0ppm, [O] ≤ 5.0ppm, take a glass tube sample to analyze the [N] content, and control [N] ≤ 50ppm; control residual [Al] ≤ 0.020%; Step 6), carefully select the ingot mold before production, preferably the ingot mold with good inner wall quality, and the use temperature ≥50℃; the flow steel bricks in the soup channel system should be dried more, and mullite flow steel bricks should be used. Carefully select them before use to ensure that the pouring system is clean and dry; the calming time is ≥10 minutes, and argon is filled in the mold and argon is used to protect the pouring before pouring; pouring temperature: 1440~1460℃; control the steel flow to enter the mold smoothly, and scattered flow pouring is not allowed. The pouring time is implemented according to the upper and lower limits, and the riser part is fully poured; medium and low carbon mold casting slag is hung in the mold, and the insufficient part is added after pouring; after adding the heating agent, carbonized rice husk is added in time to ensure the shrinkage compensation effect; the ingot is hot transported or air cooled after demoulding, and the surface is cleaned after air cooling.