Method for steelmaking by using induction furnace and electric arc furnace

Abstract

The invention discloses a method for smelting steel by using an induction furnace and an electric arc furnace in a dual connection. The induction furnace is used to melt scrap steel and perform carbon addition and temperature increase to form molten steel. After the molten steel is deslagging, it is added into an electric arc furnace for oxidation, decarbonization and phosphorus removal. The invention completes the melting period in the smelting process of the electric arc furnace in the induction furnace, reduces the oxidation loss of scrap steel in the melting process, and saves oxygen electrodes; a certain carbon addition treatment is performed in the induction furnace, and the molten steel melted in the induction furnace is added into the electric arc furnace by using a ladle for oxidation, decarbonization and dephosphorization treatment. The purity requirement of the molten steel is met through the carbon-oxygen reaction in the later oxidation and decarbonization treatment.

Description

Technical Field

[0001] The invention belongs to the technical field of scrap steel smelting, and specifically relates to a method for smelting steel using a dual-connection induction furnace and an electric arc furnace. Background Art

[0002] Competition in the heavy machinery industry market is becoming increasingly fierce. While ensuring product quality, further reducing production costs has become the foundation for heavy machinery manufacturers. The production cost of steel ingots has the greatest impact on the cost of forging products, and reducing the production cost of steel ingots has become a top priority. The traditional heavy machinery industry ingot production process is electric arc furnace + refining furnace + vacuum degassing + atmospheric injection (argon protection). The electric arc furnace is loaded with scrap steel for power transmission and oxygen blowing and melting. During the oxygen blowing and melting process, some steel materials will be oxidized and lost, and the consumption of oxygen and electrodes during the smelting and power transmission process is relatively large. If you only use induction furnace + refining furnace + vacuum degassing + atmospheric injection (argon protection), since there is no oxidation reaction process during the melting period of the induction furnace, it is difficult to meet the purity requirements of the molten steel. Summary of the invention

[0003] The purpose of the present invention is to solve the above technical problems and provide a method for smelting steel using a dual induction furnace and an electric arc furnace, which has stable operation and can reduce the burning loss of steel materials during the melting period, reduce oxygen and electrode consumption, so that the smelted steel meets the quality requirements.

[0004] To achieve the above-mentioned purpose, the present invention provides a method for smelting steel using an induction furnace and an electric arc furnace in a dual connection, wherein the induction furnace is used to melt scrap steel and perform carbon addition and temperature increase to form molten steel, and the molten steel is added to the electric arc furnace after slag removal for oxidation, decarburization, and phosphorus removal. The present invention completes the melting period in the electric arc furnace smelting process in the induction furnace, reduces the oxidation loss of scrap steel in the melting process, and saves oxygen electrodes; performs a certain carbon addition treatment in the induction furnace, and uses a ladle to add the molten steel melted in the induction furnace to the electric arc furnace for oxidation, decarburization, and dephosphorization treatment, and meets the requirements for the purity of the molten steel water through the carbon-oxygen reaction in the later oxidation and decarburization treatment.

[0005] Furthermore, the specific process of melting scrap steel and performing carbonization and heating to form molten steel in the induction furnace is as follows: adding scrap steel into the induction furnace, adding a carbonizer (carbon content 90%) in 2 to 3 batches to carbonize the scrap steel to a carbon content of 0.90 to 1.2% when half of the scrap steel is added, preventing large boiling during the addition process, and then adding the other half of the scrap steel into the induction furnace;

[0006] After all the scrap steel is melted, the temperature is raised to 1560-1580℃, samples are taken to analyze the chemical composition and the chemical composition is adjusted until it meets the target composition; then the temperature of the molten steel is raised to 1600-1620℃, the furnace is tilted and slag is removed, and the slag removal amount is ≥80%; after slag removal, the temperature is continued to be raised to 1650-1670℃ for steel tapping; after steel tapping, the molten steel is loaded into a ladle, and the ladle is then transferred to the slag removal station for slag removal, and the slag removal amount is ≥95%.

[0007] Furthermore, the molten steel is added into an electric arc furnace after deslagging for oxidation, decarburization and dephosphorization. The specific process is as follows:

[0008] Before feeding, the electric arc furnace is shaken to level and the furnace threshold is raised; first load bottom lime, then add carbon balls into the electric arc furnace according to the carbon content of the induction furnace to facilitate slag making in advance, and finally load scrap steel to form the bottom; after the feeding is completed, power is supplied for the first time, and after the well is drilled, start adding molten steel, and pour the molten steel into the "well" from above. The position where the molten steel is added should be as close to the front of the furnace as possible to facilitate oxygen blowing and decarburization, increase heat, and control the speed of molten steel addition.

[0009] After adding the molten steel, and while ensuring that the scrap steel is melted, the second power supply is sent to control the temperature of the molten pool. After the charge is melted, the third power supply is sent to control the temperature of the molten steel.

[0010] At the same time, a single-tube oxygen blowing is used to increase the oxygen supply. The depth and angle of the oxygen blowing tube can be adjusted at any time during the oxygen blowing process. In the early stage, shallow slag blowing is used for P removal. During the P removal operation, the temperature is controlled at 1540-1560℃. In the later stage, deep blowing is used for C removal to achieve dephosphorization and decarburization.

[0011] Furthermore, the amount of the recarburizer added in each batch is equal, and the total amount of the recarburizer added is 5-6 kg per ton of scrap iron.

[0012] Furthermore, the induction furnace lining adopts a neutral lining, the composition of the neutral lining includes 86-89% Al2O3 and 8-10% MgO by mass percentage, and the density is ≥3.05g / cm 3 , refractoriness is greater than 1750℃.

[0013] Furthermore, the harmful elements Sn﹤0.020%, Sb﹤0.020%, As﹤0.020%, Pb﹤0.020%, Bi﹤0.020%, Cu﹤0.25% in the scrap steel are made to have chemical purity [P]≤0.030%, [S]≤0.030% to ensure the smelting quality.

[0014] Furthermore, the first power transmission control voltage is 320-360V and the current is 20000-22000A, the second power transmission control voltage is 310-320V and the current is 22500-23500A, and the third power transmission control voltage is 290-300V and the current is 24000-25000A.

[0015] Furthermore, the amount of bottom lime is 600-800 kg; when the induction furnace is tapping steel, if C≤0.70%, carbon balls are added at 3-4 kg / ton of molten steel; if C≥0.70%, no carbon balls are added; the amount of scrap steel loaded is 2-4 t; and the molten steel is added within 1-2 minutes.

[0016] Furthermore, the oxygen blowing oxygen supply pressure is limited to 0.6-0.8 MPa.

[0017] Furthermore, the decarburization amount ΔC in the steel smelting process is ≥0.5%, the lower limit of the oxidation end point C of carbon steel is 0.03-0.10%, and the lower limit of the oxidation end point C of alloy steel is 0.05-0.15%; the sampling temperature of the end of oxidation after the removal of C and P is completed is ≥1630°C.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention completes the melting period in the electric arc furnace smelting process in the induction furnace, thereby reducing the oxidation loss of scrap steel in the melting process and saving oxygen electrodes; and performs certain carbonization treatment and slag removal operations in the induction furnace, and uses a ladle to pour the molten steel in the induction furnace into the electric arc furnace for oxidation decarburization and dephosphorization treatment, and meets the requirements for the purity of the molten steel through the carbon-oxygen reaction in the later oxidation decarburization treatment.

[0019] Compared with the traditional electric arc furnace smelting method, the steel ingot produced by this method has a steel material recovery rate increased from 85-87% to 93-95%, the electrode consumption has been reduced from 3.0-3.2 kg / ton of scrap steel to 1.0-1.2 kg / ton of scrap steel, and the oxygen consumption has been reduced from 45-48 kg / ton of scrap steel. 3 / ton of scrap steel reduced to 10 ~ 13M 3 / ton of scrap steel, and the product quality can meet the forging production needs of the heavy machinery industry. This production method can replace the electric arc furnace production method in the heavy machinery industry. DETAILED DESCRIPTION

[0020] The present invention will be further described below in conjunction with specific embodiments.

[0021] Example 1

[0022] The method of using an induction furnace and an electric arc furnace to smelt steel in pairs, uses an induction furnace to melt scrap steel and perform carbonization and temperature increase to form molten steel, and after the molten steel is deslagging, it is added into an electric arc furnace for oxidation, decarburization, and phosphorus removal. The present invention completes the melting period in the electric arc furnace smelting process in the induction furnace, reduces the oxidation loss of scrap steel in the melting process, and saves oxygen electrodes; performs a certain carbonization treatment in the induction furnace, and uses a ladle to add the molten steel melted in the induction furnace into the electric arc furnace for oxidation, decarburization, and dephosphorization treatment, and meets the requirements for the purity of the molten steel water through the carbon-oxygen reaction of the later oxidation and decarburization treatment.

[0023] The specific process of melting scrap steel in an induction furnace and performing carbon increase and heating to form molten steel is as follows: adding scrap steel into the induction furnace, and when half of the scrap steel has been added, adding carbon increaser (carbon content 90%) in two batches to increase carbon content to 1.0% to prevent large boiling during the adding process, and then adding the other half of the scrap steel into the induction furnace; the amount of carbon increaser added in the two batches is equal, and the total amount of carbon increaser added is 5kg of carbon increaser per ton of scrap iron.

[0024] After all the scrap steel is melted, the temperature is raised to 1580℃, samples are taken to analyze the chemical composition and the chemical composition is adjusted until it meets the target composition; then the temperature of the molten steel is raised to 1620℃, the furnace is tilted and slag is removed, and the slag removal amount is ≥80%; after slag removal, the temperature is continued to be raised to 1650℃ for steel tapping; after steel tapping, the molten steel is loaded into a ladle, and the ladle is then transferred to the slag removal station for slag removal, and the slag removal amount is ≥95%.

[0025] After the molten steel is deslagging, it is added into the electric arc furnace for oxidation, decarburization and dephosphorization. The specific process is as follows:

[0026] Before feeding, the electric arc furnace is shaken to level and the furnace threshold is raised; first, 800 kg of bottom lime is loaded, and then carbon balls are added into the electric arc furnace according to the carbon content of the induction furnace (C≤0.70% when the induction furnace is tapping steel, and carbon balls are added at 3 kg / ton of molten steel) to facilitate slag making in advance, and finally 2 tons of scrap steel is loaded as the base; after the feeding is completed, power is supplied for the first time, and after the well drilling is completed, molten steel is started to be added, and the molten steel is poured into the "well" from above. The position where the molten steel is added should be as close to the front of the furnace as possible to facilitate oxygen blowing and decarburization, increase the heat, and control the speed of molten steel addition, and the molten steel should be added within 1 minute.

[0027] After adding the molten steel, and while ensuring the melting of scrap steel, power is supplied for the second time to control the molten pool temperature. After the charge is melted, power is supplied for the third time to control the molten steel temperature. The first power supply controls the voltage at 340V and the current at 21000A, the second power supply controls the voltage at 319V and the current at 22000A, and the third power supply controls the voltage at 300V and the current at 24000A.

[0028] At the same time, a single-tube oxygen blowing is used to increase the oxygen supply. The oxygen blowing pressure is limited to 0.6-0.8MPa. The depth and angle of the oxygen blowing tube can be adjusted at any time during the oxygen blowing process. In the early stage, shallow slag blowing is used for P removal. During the P removal operation, the temperature is controlled at 1540℃. In the later stage, deep blowing is used for C removal to achieve dephosphorization and decarburization.

[0029] In the above steel smelting process, the decarburization amount △C is ≥0.5%, the lower limit of the oxidation end point C of carbon steel is 0.03-0.10%, and the lower limit of the oxidation end point C of alloy steel is 0.05-0.15%; the sampling temperature of the end of oxidation after decarbonization and dephosphorization is completed is ≥1630℃.

[0030] In the above, the induction furnace lining adopts a neutral lining, the composition of the neutral lining includes 86-89% Al2O3 and 8-10% MgO by mass percentage, and the density is ≥3.05g / cm 3 , refractoriness is greater than 1750℃.

[0031] The harmful elements Sn﹤0.020%, Sb﹤0.020%, As﹤0.020%, Pb﹤0.020%, Bi﹤0.020%, Cu﹤0.25% in scrap steel should be controlled to make [P]≤0.030%, [S]≤0.030% to ensure the smelting quality.

[0032] Compared with the traditional electric arc furnace smelting method, the steel ingot produced by this method can increase the steel material recovery rate from the original 87% to 93%, the electrode consumption is reduced from the original 3.2Kg / ton of scrap steel to 1.2Kg / ton of scrap steel, and the oxygen consumption is reduced from the original 48M 3 / ton of scrap steel reduced to 13M 3 / ton of scrap steel.

[0033] Example 2

[0034] The method of using an induction furnace and an electric arc furnace to smelt steel in pairs, uses an induction furnace to melt scrap steel and perform carbonization and temperature increase to form molten steel, and after the molten steel is deslagging, it is added into an electric arc furnace for oxidation, decarburization, and phosphorus removal. The present invention completes the melting period in the electric arc furnace smelting process in the induction furnace, reduces the oxidation loss of scrap steel in the melting process, and saves oxygen electrodes; performs a certain carbonization treatment in the induction furnace, and uses a ladle to add the molten steel melted in the induction furnace into the electric arc furnace for oxidation, decarburization, and dephosphorization treatment, and meets the requirements for the purity of the molten steel water through the carbon-oxygen reaction of the later oxidation and decarburization treatment.

[0035] The specific process of melting scrap steel in an induction furnace and performing carbon increase and heating to form molten steel is as follows: adding scrap steel into the induction furnace, and when half of the scrap steel has been added, adding carbon increaser (carbon content 90%) in three batches to increase carbon content to 1.2% to prevent large boiling during the adding process, and then adding the other half of the scrap steel into the induction furnace; the amount of carbon increaser added in the two batches is equal, and the total amount of carbon increaser added is 6 kg of carbon increaser per ton of scrap iron.

[0036] After all the scrap steel is melted, the temperature is raised to 1560℃, samples are taken to analyze the chemical composition and the chemical composition is adjusted until it meets the target composition; then the temperature of the molten steel is raised to 1600℃, the furnace is tilted and slag is removed, and the slag removal amount is ≥80%; after slag removal, the temperature is continued to be raised to 1670℃ for steel tapping; after steel tapping, the molten steel is loaded into a ladle, and the ladle is then transferred to the slag removal station for slag removal, and the slag removal amount is ≥95%.

[0037] After the molten steel is deslagging, it is added into the electric arc furnace for oxidation, decarburization and dephosphorization. The specific process is as follows:

[0038] Before feeding, the electric arc furnace is shaken to level and the furnace threshold is raised; first, 600 kg of bottom lime is loaded, and then carbon balls are added into the electric arc furnace according to the carbon content of the induction furnace (C≤0.70% when the induction furnace is tapping steel, and carbon balls are added at 4 kg / ton of molten steel) to facilitate slag making in advance, and finally 2 tons of scrap steel is loaded as the base; after the feeding is completed, power is supplied for the first time, and after the well drilling is completed, molten steel is started to be added, and the molten steel is poured into the "well" from above. The position where the molten steel is added should be as close to the front of the furnace as possible to facilitate oxygen blowing and decarburization, increase the heat, and control the speed of molten steel addition. The molten steel should be added within 2 minutes.

[0039] After adding the molten steel, and while ensuring the melting of scrap steel, power is supplied for the second time to control the molten pool temperature. After the charge is melted, power is supplied for the third time to control the molten steel temperature. The first power supply controls the voltage at 320V and the current at 20000A, the second power supply controls the voltage at 320V and the current at 22500A, and the third power supply controls the voltage at 290V and the current at 25000A.

[0040] At the same time, a single-tube oxygen blowing is used to increase the oxygen supply. The oxygen blowing pressure is limited to 0.6-0.8MPa. The depth and angle of the oxygen blowing tube can be adjusted at any time during the oxygen blowing process. In the early stage, shallow slag blowing is used for P removal. During the P removal operation, the temperature is controlled at 1560℃. In the later stage, deep blowing is used for C removal to achieve dephosphorization and decarburization.

[0041] In the above steel smelting process, the decarburization amount △C is ≥0.5%, the lower limit of the oxidation end point C of carbon steel is 0.03-0.10%, and the lower limit of the oxidation end point C of alloy steel is 0.05-0.15%; the sampling temperature of the end of oxidation after decarbonization and dephosphorization is completed is ≥1630℃.

[0042] Compared with the traditional electric arc furnace smelting method, the steel ingot produced by this method can increase the steel material recovery rate from the original 87% to 95%, the electrode consumption is reduced from the original 3.0Kg / ton of scrap steel to 1.2Kg / ton of scrap steel, and the oxygen consumption is reduced from the original 46M 3 / ton of scrap steel reduced to 12M 3 / ton of scrap steel.

[0043] Example 3

[0044] The method of using an induction furnace and an electric arc furnace to smelt steel in pairs, uses an induction furnace to melt scrap steel and perform carbonization and temperature increase to form molten steel, and after the molten steel is deslagging, it is added into an electric arc furnace for oxidation, decarburization, and phosphorus removal. The present invention completes the melting period in the electric arc furnace smelting process in the induction furnace, reduces the oxidation loss of scrap steel in the melting process, and saves oxygen electrodes; performs a certain carbonization treatment in the induction furnace, and uses a ladle to add the molten steel melted in the induction furnace into the electric arc furnace for oxidation, decarburization, and dephosphorization treatment, and meets the requirements for the purity of the molten steel water through the carbon-oxygen reaction of the later oxidation and decarburization treatment.

[0045] The specific process of melting scrap steel in an induction furnace and performing carbon increase and heating to form molten steel is as follows: adding scrap steel into the induction furnace, and when half of the scrap steel has been added, adding carbon increaser (carbon content 90%) in three batches to increase carbon content to 1.2% to prevent large boiling during the adding process, and then adding the other half of the scrap steel into the induction furnace; the amount of carbon increaser added in the two batches is equal, and the total amount of carbon increaser added is 6 kg of carbon increaser per ton of scrap iron.

[0046] After all the scrap steel is melted, the temperature is raised to 1570℃, samples are taken to analyze the chemical composition and the chemical composition is adjusted until it meets the target composition; then the temperature of the molten steel is raised to 1610℃, the furnace is tilted and slag is removed, and the slag removal amount is ≥80%; after slag removal, the temperature is continued to be raised to 1660℃ for steelmaking; after steelmaking, the molten steel is loaded into a ladle, and the ladle is then transferred to the slag removal station for slag removal, and the slag removal amount is ≥95%.

[0047] After the molten steel is deslagging, it is added into the electric arc furnace for oxidation, decarburization and dephosphorization. The specific process is as follows:

[0048] Before feeding, the electric arc furnace is shaken to level and the furnace threshold is raised; first, 700 kg of bottom lime is loaded, and then carbon balls are added to the electric arc furnace according to the carbon content of the induction furnace (carbon balls are not added when C ≥ 0.70% during steelmaking from the induction furnace) to facilitate slag making in advance, and finally 3 tons of scrap steel is loaded to form the bottom; after the feeding is completed, power is supplied for the first time, and after the well is drilled, molten steel is added, and the molten steel is poured into the "well" from above. The position where the molten steel is added should be as close to the front of the furnace as possible to facilitate oxygen blowing and decarburization, increase the heat, and control the speed of molten steel addition. The molten steel should be added within 2 minutes.

[0049] After adding the molten steel, and while ensuring the melting of scrap steel, power is supplied for the second time to control the molten pool temperature. After the charge is melted, power is supplied for the third time to control the molten steel temperature. The first power supply controls the voltage at 360V and the current at 21500A, the second power supply controls the voltage at 310V and the current at 23500A, and the third power supply controls the voltage at 295V and the current at 25000A.

[0050] At the same time, a single-tube oxygen blowing is used to increase the oxygen supply. The oxygen blowing pressure is limited to 0.6-0.8MPa. The depth and angle of the oxygen blowing tube can be adjusted at any time during the oxygen blowing process. In the early stage, shallow slag blowing is used for P removal. During the P removal operation, the temperature is controlled at 1560℃. In the later stage, deep blowing is used for C removal to achieve dephosphorization and decarburization.

[0051] In the above steel smelting process, the decarburization amount △C is ≥0.5%, the lower limit of the oxidation end point C of carbon steel is 0.03-0.10%, and the lower limit of the oxidation end point C of alloy steel is 0.05-0.15%; the sampling temperature of the end of oxidation after decarbonization and dephosphorization is completed is ≥1630℃.

[0052] Compared with the traditional electric arc furnace smelting method, the steel ingot produced by this method can increase the steel material recovery rate from the original 85% to 93%, the electrode consumption is reduced from the original 3.1Kg / ton of scrap steel to 1.1Kg / ton of scrap steel, and the oxygen consumption is reduced from the original 45M 3 / ton of scrap steel reduced to 10M 3 / ton of scrap steel.

Claims

1. A method for steelmaking using an induction furnace and an electric arc furnace, characterized in that: An induction furnace is used to melt scrap steel and increase carbon and temperature to form molten steel. After slag removal, the molten steel is added into an electric arc furnace for oxidation, decarburization and dephosphorization.

2. The method for steelmaking using a dual induction furnace and an electric arc furnace according to claim 1, characterized in that: The specific process of melting scrap steel and performing carbonization and heating to form molten steel in the induction furnace is as follows: adding scrap steel into the induction furnace, adding a carbonizer in 2 to 3 batches to carbonize the scrap steel until the carbon content reaches 0.90 to 1.2% when half of the scrap steel is added, and then adding the other half of the scrap steel into the induction furnace; After all the scrap steel is melted, the temperature is raised to 1560-1580℃, samples are taken to analyze the chemical composition and the chemical composition is adjusted until it meets the target composition; then the temperature of the molten steel is raised to 1600-1620℃, the furnace is tilted and slag is removed, and the slag removal amount is ≥80%; after slag removal, the temperature is continued to be raised to 1650-1670℃ for steel tapping; after steel tapping, the molten steel is loaded into a ladle, and the ladle is then transferred to the slag removal station for slag removal, and the slag removal amount is ≥95%.

3. The method for steelmaking using a dual-connection induction furnace and an electric arc furnace according to claim 2, characterized in that: After the slag removal, the molten steel is added into an electric arc furnace for oxidation, decarburization and dephosphorization. The specific process is as follows: Before feeding, the electric arc furnace is shaken to level and the furnace threshold is raised; first load the bottom lime, then add carbon balls into the electric arc furnace according to the carbon content of the induction furnace, and finally load the scrap steel as the bottom; after the feeding is completed, power is supplied for the first time, and after the drilling is completed, start adding molten steel and control the speed of adding molten steel. After adding the molten steel, and while ensuring that the scrap steel is melted, the second power supply is sent to control the temperature of the molten pool. After the charge is melted, the third power supply is sent to control the temperature of the molten steel. At the same time, a single-tube oxygen blowing is used to increase the oxygen supply. The depth and angle of the oxygen blowing tube can be adjusted at any time during the oxygen blowing process. In the early stage, shallow slag blowing is used for P removal. During the P removal operation, the temperature is controlled at 1540-1560℃. In the later stage, deep blowing is used for C removal to achieve dephosphorization and decarburization.

4. The method for steelmaking using a dual induction furnace and an electric arc furnace according to claim 2, characterized in that: The amount of the recarburizer added in each batch is equal, and the total amount of the recarburizer added is 5-6 kg of recarburizer per ton of scrap iron.

5. The method for steelmaking using a dual induction furnace and an electric arc furnace according to claim 1, characterized in that: The induction furnace lining adopts a neutral lining, the composition of the neutral lining includes 86-89% Al2O3 and 8-10% MgO by mass percentage, and the density is ≥3.05g / cm 3 , refractoriness is greater than 1750℃.

6. The method for steelmaking using a dual induction furnace and an electric arc furnace according to claim 1, characterized in that: The harmful elements Sn﹤0.020%, Sb﹤0.020%, As﹤0.020%, Pb﹤0.020%, Bi﹤0.020%, Cu﹤0.25% in the scrap steel are made to be chemically purified to achieve [P]≤0.030% and [S]≤0.030%.

7. The method for steelmaking using a dual induction furnace and an electric arc furnace according to claim 3, characterized in that: The first power transmission control voltage is 320-360V and the current is 20000-22000A, the second power transmission control voltage is 310-320V and the current is 22500-23500A, and the third power transmission control voltage is 290-300V and the current is 24000-25000A.

8. The method for steelmaking using a dual induction furnace and an electric arc furnace according to claim 3, characterized in that: The amount of bottom lime is 600-800kg; when the induction furnace is tapping steel, if C≤0.70%, carbon balls are added at 3-4kg / ton of molten steel, and if C≥0.70%, no carbon balls are added; the amount of scrap steel loaded is 2-4t; and the molten steel is added within 1-2 minutes.

9. The method for steelmaking using a dual induction furnace and an electric arc furnace according to claim 3, characterized in that: The oxygen blowing and supply pressure is limited to 0.6-0.8 MPa.

10. The method for steelmaking using a dual-connection induction furnace and an electric arc furnace according to claim 3, characterized in that: The decarburization amount ΔC in the steel smelting process is ≥0.5%, the lower limit of the oxidation end point C of carbon steel is 0.03-0.10%, and the lower limit of the oxidation end point C of alloy steel is 0.05-0.15%; the sampling temperature of the end of oxidation after the removal of C and P is completed is ≥1630°C.