CN110616362A - Steelmaking method of high manganese steel for low-temperature environment - Google Patents

Abstract

The invention discloses a steelmaking method of high manganese steel for a low-temperature environment, which comprises the working procedures of electric furnace steelmaking, LF refining furnace refining and VD furnace refining, wherein the electric furnace steelmaking comprises the steps of electric furnace charging, smelting power supply, steelmaking oxygen blowing process, slag charging and steel tapping, the LF refining furnace refining comprises the steps of ladle heating, refining white slag, deoxidation and desulfurization and alloy addition, and the VD furnace refining comprises the steps of molten steel component fine adjustment, vacuumizing treatment, argon control and soft blowing after vacuum breaking. The molten high manganese steel produced by the steelmaking method of the invention comprises the following steps: the Mn is more than or equal to 22.5 percent, the P is less than or equal to 0.007 percent, the S is less than or equal to 0.003 percent, and the manganese alloy yield is more than or equal to 96 percent, so that the technical problems of high manganese alloy content, high yield, strict requirements on phosphorus and sulfur impurities, high difficulty in steel-making production and the like of the high manganese steel for the low-temperature environment are solved, a feasible scheme is provided for large-scale production of the high manganese steel for the low-temperature environment in the aspect of steel-making, and the method can be widely used in.

Description

Steelmaking method of high manganese steel for low-temperature environment

Technical Field

The invention belongs to the technical field of metallurgy, and particularly relates to a steel-making method of high manganese steel used in a low-temperature environment.

Background

At present, the low-temperature steel plate and the ultralow-temperature steel plate mainly use 9Ni steel, for example, Liquefied Natural Gas (LNG) is usually stored and transported at-163 ℃, the material for the LNG storage tank is 9Ni steel, and because noble metal nickel is used as a main alloy element in the steel and is delivered in a heat treatment state, the 9Ni steel needs a large amount of precious nickel resources to be alloyed in the production and manufacturing process, so the resource consumption pressure is high, and the corresponding production cost is high, and therefore, a novel steel plate material for the ultralow-temperature environment is urgently needed to be developed.

The high manganese steel for low temperature environment adds certain Mn element into the steel to make the steel plate present austenite structure characteristic at room temperature, the performances of low-temperature strength, toughness, fatigue resistance, corrosion resistance and the like of the alloy are not much different from those of 9Ni steel, the plasticity of the alloy is far superior to that of 9Ni steel, the ideal performance of the high manganese steel used in low temperature environment can be kept under the extremely low temperature condition, and the production cost is far lower than that of the 9Ni steel, the market prospect is good, but the high manganese steel used in low temperature environment has high alloy content, strict requirements on phosphorus and sulfur impurity elements, the manganese alloy content of general steel is less than or equal to 2 percent, the manganese content of the steel grade is more than or equal to 22.5 percent, the metal manganese is a strong oxidizing element and is easy to oxidize to form oxidizing slag, and the steel is faced with the high manganese alloy, how to add, how to melt, how to ensure the yield of manganese alloy, how to ensure the purity of molten steel and the like are problems which need to be solved urgently.

Disclosure of Invention

The invention aims to provide a steel-making method of high manganese steel used in low-temperature environment.

In order to solve the technical problems, the invention adopts the technical scheme that: a steel-making method of high manganese steel used in low temperature environment comprises the working procedures of electric furnace steel-making, LF refining furnace refining and VD furnace refining, and the specific process steps are as follows:

(1) an electric furnace steelmaking process: the electric furnace steelmaking comprises electric furnace charging, smelting power supply, steelmaking oxygen blowing process, slag charge adding and steel tapping;

a. when an electric furnace is charged, controlling the charging proportion of molten iron according to 35-40%, and taking the rest as scrap steel;

b. smelting and supplying power, wherein medium voltage is adopted during arcing to keep relatively stable electric arc combustion, waste steel is quickly penetrated through a well to prevent strong electric arc from radiating a furnace cover, the electric arc is shielded after being electrified for 1-2 min, the maximum power supply is used for accelerating melting, and when the waste steel is melted for 65-70%, the power supply is reduced to continuously supply power, increase the temperature and melt;

c. in the steelmaking oxygen blowing process, the initial oxygen blowing period is 3-5 min from the beginning of oxygen blowing, the oxygen lance is selected to be in a burner mode, scrap steel around the oxygen lance is rapidly heated, the middle oxygen blowing period is 6-15 min, the oxygen lance blows oxygen in a supersonic speed mode to finish molten steel decarburization and stirring tasks, the later oxygen blowing period is 16-18 min, carbon powder of 5-8 kg/t steel is blown into a molten pool according to the condition of foamed slag, submerged arc operation is carried out, the electric energy utilization rate is improved, and the heat transfer rate is accelerated;

d. adding slag materials, wherein in the melting period of each basket of materials, lime is added for slagging after power is transmitted for 3-5 min, the total amount of added lime is 25-30 kg/t steel, 70% of the total amount of lime is added in the melting period, lime with the total amount of 30% is added after sampling and slag flowing, light-burned dolomite is added according to the condition of slag to increase the MgO content in the slag to 6-8%, and if the effect of foamed slag is poor, the carbon can be sprayed for adjustment;

e. tapping by an electric furnace, wherein molten steel components and temperature at the tapping end point meet requirements, opening an argon blowing valve at the bottom of a ladle, enabling argon flow to be 50-60 NL/min, opening a tapping hole inserting plate, starting tapping, controlling the tapping amount to be 75-78% of the total planned smelting amount, enabling the molten steel P to be less than or equal to 0.005%, enabling the inclination angle of a furnace body to be 15-40 degrees during tapping, ensuring smooth and stable tapping, closely observing a tapping counter and the steel flow, immediately tilting the furnace body when the planned tapping amount or the slag discharge amount is reached, confirming that argon is smooth after tapping, keeping the argon flow, and ensuring slag-free tapping;

(2) and (3) refining process of an LF refining furnace: the LF refining furnace refining comprises seat ladle heating, refining for making white slag, deoxidizing and desulfurizing and adding alloy;

heating an LF refining ladle, blowing argon to measure temperature after the LF refining ladle, wherein the flow of the argon is 80-100 NL/min, carrying out power transmission and heating according to the temperature condition, wherein the power transmission and heating time is 20-25 min, and the heating is carried out to 1580-1600 ℃;

b. refining to produce white slag, wherein in the refining and heating process, 8-10 kg/t of steel carbon powder is added for pre-deoxidation, 3-4 kg/t of steel lime and 1.5-2.0 kg/t of steel fluorite are added for primary submerged arc slagging, 3-5 kg/t of steel ferrosilicon is added for deoxidation, 2.0-3.0 kg/t of steel calcium carbide auxiliary submerged arc is added in front of a furnace, the slag condition in the process is dilute and suitable, the submerged arc is good, and the white slag is kept all the time;

c. deoxidizing and desulfurizing, wherein when the temperature of molten steel rises to 1580-1600 ℃, power transmission is stopped, 0.7-0.9 kg/t of steel Al wire is fed for deoxidizing and desulfurizing, the flow of argon is adjusted to 500-600 NL/min, the large argon is fully stirred for deoxidizing and desulfurizing, the end point O is less than or equal to 0.0030 percent, and the end point S is less than or equal to 0.003 percent;

d. adding alloy, namely starting to add manganese alloy after white slag is formed in refining slag, adding 18-20 kg/t of steel manganese alloy each time, then feeding power, raising the temperature and melting the alloy, adding the manganese alloy after the manganese alloy is completely melted, and then feeding power, raising the temperature and melting, wherein the manganese alloy is continuously added in such a way to meet the component requirement;

(3) and a VD furnace refining process: the VD furnace refining comprises fine adjustment of molten steel components, vacuumizing treatment, argon control and soft blowing after air breaking;

a. the preparation before vacuumizing, after the molten steel is subjected to LF refining treatment, the component temperature meets the requirement, the steel slag is well deoxidized and has good fluidity, the free space of the liquid level of the steel ladle is more than or equal to 800mm, and the good argon blowing at the bottom of the steel ladle is ensured;

b. fine adjustment of molten steel components to enable the molten steel components to meet internal control requirements;

c. vacuumizing, wherein the vacuum degree is less than or equal to 66.7Pa, and the vacuum retention time is more than or equal to 10 min;

d. argon is used for controlling, wherein the argon is adopted 4-5 min before vacuum maintenance, the argon flow is controlled to be 200-240 NL/min, the argon is turned to be small to be in a soft blowing state in the later period of vacuum maintenance, and the argon flow is controlled to be 50-80 NL/min;

e. and (3) soft blowing is carried out after the vacuum is broken, the soft blowing is carried out for 10-15 min after the vacuum is finished, the argon flow is controlled to be 30-50 NL/min in the soft blowing process, meanwhile, the carbonized rice hulls are added on the slag surface to prevent molten steel from sucking air, and the steel is poured by a ladle.

The invention relates to scrap steel used for charging an electric furnace in the step (1): the alloy content is less than or equal to 2.0 percent, P is less than or equal to 0.020 percent, and S is less than or equal to 0.10 percent.

In the step (1), a medium power supply voltage of 600-700 KV is firstly adopted during smelting power supply and arc striking.

According to the invention, after the smelting power supply in the step (1) is electrified for 1-2 min, the electric arc is shielded, and the 1000KW maximum power supply is used for accelerating melting.

When 65-70% of smelting power supply scrap steel in the step (1) is melted, reducing power supply to 700-800 KW, and continuing to supply power, raise temperature and melt.

The molten high manganese steel produced by the steelmaking method of the invention comprises the following steps: c: 0.35-0.55%, Si: 0.10-0.50%, Mn is more than or equal to 22.5%, P is less than or equal to 0.007%, S is less than or equal to 0.003%, Cr: 3.00-4.00%, Cu: 0.30-0.70%, and the balance of Fe and inevitable impurities.

The high manganese steel molten steel produced by the steelmaking method has the Mn of more than or equal to 22.5 percent, the manganese alloy yield of more than or equal to 96 percent, high molten steel purity, low impurity content of P, S, P of less than or equal to 0.007 percent and S of less than or equal to 0.003 percent, and meets the technical requirements of high manganese alloy content, high yield and low phosphorus and sulfur impurity content.

Adopt the produced beneficial effect of above-mentioned technical scheme to lie in: 1. according to the invention, the molten steel is subjected to deoxidation and desulfurization treatment before a large amount of Mn alloy is added, the Mn alloy is added after slag is whitened, and a mode of adding and heating for melting is adopted in the Mn alloy adding process, so that the problems that excessive Mn alloy is added at one time, a large amount of Mn alloy floats on the molten steel to cause power transmission difficulty and the total smelting time is too long due to alloy adding in power failure are avoided. 2. In order to reduce the P, S content in molten steel, the P content in the steel is strictly controlled when the steel is tapped from the primary smelting furnace, the P content of the steel tapped from the primary smelting furnace is ensured to be less than or equal to 0.05 percent, and the P is removed again at an LF refining position after the steel is tapped from the converter; the auxiliary material added in the LF refining adopts the auxiliary material with low P, S content, and the use amount of lime is increased and the stirring time of argon gas is prolonged compared with the common steel in the LF position S removing process. 3. The invention solves the technical problems of high manganese alloy content, strict requirements on phosphorus and sulfur impurity content, high difficulty in steel-making production and the like of the high manganese steel used in the low-temperature environment, provides a feasible scheme for large-scale production of the high manganese steel used in the low-temperature environment in the aspect of steel making, and can be widely applied to steel-making production of the high manganese steel. 4. The high manganese steel molten steel produced by the steelmaking method of the invention has Mn more than or equal to 22.5 percent, manganese alloy yield more than or equal to 96 percent, high molten steel purity, P, S low impurity content, P less than or equal to 0.007 percent and S less than or equal to 0.003 percent, and meets the technical requirements of high manganese alloy content, high yield and low phosphorus and sulfur impurity content.

Detailed Description

The present invention will be described in further detail with reference to specific examples.

Example 1

The steel-making method of the high manganese steel for the low-temperature environment comprises the working procedures of electric furnace steel-making, LF refining furnace refining and VD furnace refining, and the specific process steps are as follows:

(1) an electric furnace steelmaking process: the electric furnace steelmaking comprises electric furnace charging, smelting power supply, steelmaking oxygen blowing process, slag charge adding and steel tapping;

a. when the electric furnace is charged, the charging proportion of molten iron is 35 percent, and the balance is scrap steel;

b. smelting and supplying power, wherein 620KV medium power supply voltage is adopted during arc starting, an arc is shielded after the arc is electrified for 2min, 1000KW maximum power supply power is used for accelerating melting, and when 65% of scrap steel is melted, the power supply power is reduced to 730KW for continuous power supply, temperature rise and melting are carried out;

c. in the steelmaking oxygen blowing process, the initial oxygen blowing period is 3-5 min from the beginning of oxygen blowing, the oxygen lance is selected to be in a burner mode, scrap steel around the oxygen lance is rapidly heated, the middle oxygen blowing period is 6-15 min, the oxygen lance blows oxygen in a supersonic speed mode to finish molten steel decarburization and stirring tasks, the later oxygen blowing period is 16-18 min, carbon powder of 7kg/t steel is blown to a molten pool according to the condition of foamed slag, submerged arc operation is carried out, the utilization rate of electric energy is improved, and the heat transfer rate is accelerated;

d. adding slag materials, wherein in the melting period of each basket of materials, lime is added for slagging after 5min of power transmission, the total amount of added lime is 25kg/t steel, 70% of the total amount of lime is added in the melting period, 30% of lime is added after sampling and slag flowing, and light-burned dolomite is added according to the condition of slag to increase the MgO content in the slag to 6%;

e. tapping steel from an electric furnace, opening a ladle bottom argon blowing valve, opening a tap hole inserting plate with argon flow of 60NL/min, starting tapping, controlling the tapping amount to be 75% of the total planned smelting amount, and adding molten steel P: 0.005 percent, the tilting angle of the furnace body is 15 degrees when tapping, the smooth and stable tapping is ensured, the tapping counter and the steel flow are closely observed, the furnace body is immediately tilted when the tapping amount is reached, the argon is ensured to be smooth after tapping, the argon flow is kept, and the slag-free tapping is ensured;

(2) and (3) refining process of an LF refining furnace: the LF refining furnace refining comprises seat ladle heating, refining for making white slag, deoxidizing and desulfurizing and adding alloy;

heating an LF refining ladle, blowing argon to measure temperature after the LF refining ladle, wherein the argon flow is 90NL/min, carrying out power transmission heating according to the temperature condition, and carrying out power transmission heating for 20min to 1580 ℃;

b. refining to produce white slag, wherein in the refining and heating process, 8kg/t of steel carbon powder is added for pre-deoxidation, 3kg/t of steel lime and 1.5kg/t of steel fluorite are added for primary submerged arc slagging, 5kg/t of steel ferrosilicon is added for deoxidation, 3.0kg/t of steel calcium carbide auxiliary submerged arc is added in front of a furnace, the process slag condition is dilute and suitable, the submerged arc is better, and the white slag is kept all the time;

c. and (3) deoxidizing and desulfurizing, wherein when the temperature of molten steel is increased to 1580 ℃, power transmission is stopped to feed 0.8kg/t of steel Al wire, deoxidizing and desulfurizing are carried out, meanwhile, the flow of argon is adjusted to 500NL/min, large argon is fully stirred and desulfurized, and the end point O: 0.0020%, S: 0.002%;

d. adding alloy, namely adding manganese alloy after white slag is formed in refining slag, adding 18kg/t of steel manganese alloy each time, then feeding power, raising the temperature and melting the alloy, adding the manganese alloy after the manganese alloy is completely melted, feeding power, raising the temperature and melting, and continuously adding the manganese alloy in such a way to meet the component requirement;

(3) and a VD furnace refining process: the VD furnace refining comprises fine adjustment of molten steel components, vacuumizing treatment, argon control and soft blowing after air breaking;

a. the preparation before vacuumizing, after the molten steel is subjected to LF refining treatment, the component temperature meets the requirement, the steel slag is good in deoxidation and good in fluidity, the free space of the liquid level of a steel ladle is 1000mm, and the good argon blowing at the bottom of the steel ladle is ensured;

b. fine adjustment of molten steel components to enable the molten steel components to meet internal control requirements;

c. vacuumizing, wherein the vacuum degree is 66.7Pa, and the vacuum retention time is 10 min;

d. argon control, wherein large argon is adopted 4min before vacuum maintaining, the argon flow is 200NL/min, the argon is reduced to a soft blowing state in the later period of vacuum maintaining, and the argon flow is 80 NL/min;

e. and (3) soft blowing is carried out after the air is broken, soft blowing is carried out for 10min after the vacuum is finished, the argon flow in the soft blowing process is 50NL/min, meanwhile, the carbonized rice hulls are added on the slag surface to prevent the molten steel from sucking air, and the steel is poured by a ladle.

The molten steel produced by the high manganese steel making method in the low-temperature environment of the embodiment comprises the following steps: mn: 24%, P: 0.006%, S: 0.002 percent and 96 percent of manganese alloy yield, and meets the technical requirements of high manganese alloy content, high yield and low phosphorus and sulfur impurity content.

Example 2

The steel-making method of the high manganese steel for the low-temperature environment comprises the working procedures of electric furnace steel-making, LF refining furnace refining and VD furnace refining, and the specific process steps are as follows:

(1) an electric furnace steelmaking process: the electric furnace steelmaking comprises electric furnace charging, smelting power supply, steelmaking oxygen blowing process, slag charge adding and steel tapping;

a. when the electric furnace is charged, the charging proportion of molten iron is 40 percent, and the balance is scrap steel;

b. smelting and supplying power, wherein a 650KV medium power supply voltage is adopted during arc striking, an arc is shielded after the arc is electrified for 1min, the 1000KW maximum power supply power is used for accelerating melting, and when 70% of scrap steel is melted, the power supply power is reduced to 750KW for continuous power supply, temperature rise and melting are carried out;

c. in the steelmaking oxygen blowing process, the initial oxygen blowing period is 3-5 min from the beginning of oxygen blowing, the oxygen lance is selected to be in a burner mode, scrap steel around the oxygen lance is rapidly heated, the middle oxygen blowing period is 6-15 min, the oxygen lance blows oxygen in a supersonic speed mode to finish molten steel decarburization and stirring tasks, the later oxygen blowing period is 16-18 min, carbon powder of 8kg/t steel is blown into a molten pool according to the condition of foamed slag, submerged arc operation is carried out, the utilization rate of electric energy is improved, and the heat transfer rate is accelerated;

d. adding slag materials, wherein in the melting period of each basket of materials, lime is added for slagging after power is transmitted for 3min, the total amount of added lime is 30kg/t steel, 70 percent of the total amount of lime is added in the melting period, 30 percent of lime is added after sampling and slag flowing, and light-burned dolomite is added according to the condition of slag to increase the MgO content in the slag to 7 percent;

e. tapping steel from an electric furnace, opening a ladle bottom argon blowing valve, opening a tap hole inserting plate with argon flow of 50NL/min, starting tapping, controlling the tapping amount to be 78% of the total planned smelting amount, and adding molten steel P: 0.003 percent, when tapping, the tilting angle of the furnace body is 25 degrees, ensure smooth and steady tapping, observe tapping counter and steel flow closely, return to the furnace body immediately when reaching the tapping amount, confirm the argon is unblocked after tapping, and keep the argon flow, guarantee the slag-free tapping;

(2) and (3) refining process of an LF refining furnace: the LF refining furnace refining comprises seat ladle heating, refining for making white slag, deoxidizing and desulfurizing and adding alloy;

heating an LF refining ladle, blowing argon to measure temperature after the LF refining ladle, wherein the argon flow is 90NL/min, carrying out power transmission and heating according to the temperature condition, wherein the power transmission and heating time is 20min, and the temperature is raised to 1600 ℃;

b. refining to produce white slag, wherein in the refining and heating process, 10kg/t of steel carbon powder is added for pre-deoxidation, 4kg/t of steel lime and 1.5kg/t of steel fluorite are added for primary submerged arc slagging, 4kg/t of steel ferrosilicon is added for deoxidation, 3.0kg/t of steel calcium carbide auxiliary submerged arc is added in front of a furnace, the process slag condition is dilute and suitable, the submerged arc is better, and the white slag is kept all the time;

c. and (3) deoxidizing and desulfurizing, wherein when the temperature of molten steel is increased to 1600 ℃, the Al wire of 0.8kg/t steel is fed in by stopping power transmission, deoxidizing and desulfurizing are carried out, meanwhile, the flow of argon is adjusted to 600NL/min, the large argon is fully stirred and desulfurized, and the end point O: 0.0030%, S: 0.003%;

d. adding alloy, namely adding manganese alloy after white slag is formed in refining slag, adding 20kg/t of steel manganese alloy each time, then feeding power, raising the temperature and melting the alloy, adding the manganese alloy after the manganese alloy is completely melted, and feeding power, raising the temperature and melting the manganese alloy, wherein the manganese alloy is continuously added in such a way to meet the component requirement;

(3) and a VD furnace refining process: the VD furnace refining comprises fine adjustment of molten steel components, vacuumizing treatment, argon control and soft blowing after air breaking;

a. the preparation before vacuumizing, after the molten steel is subjected to LF refining treatment, the component temperature meets the requirement, the steel slag is good in deoxidation and good in fluidity, the free space of the liquid level of a steel ladle is 800mm, and the good argon blowing at the bottom of the steel ladle is ensured;

b. fine adjustment of molten steel components to enable the molten steel components to meet internal control requirements;

c. vacuumizing, wherein the vacuum degree is 66.7Pa, and the vacuum retention time is 11 min;

d. argon control, wherein large argon is adopted 5min before vacuum maintenance, the argon flow is 240NL/min, the argon is reduced to a soft blowing state in the later period of vacuum maintenance, and the argon flow is 50 NL/min;

e. and (3) soft blowing is carried out after the air is broken, soft blowing is carried out for 15min after the vacuum is finished, the argon flow in the soft blowing process is 30NL/min, meanwhile, the carbonized rice hulls are added on the slag surface to prevent the molten steel from sucking air, and the steel is poured by a ladle.

The molten steel produced by the high manganese steel making method in the low-temperature environment of the embodiment comprises the following steps: mn: 23%, P: 0.007%, S: 0.003 percent and the manganese alloy yield is 97 percent, and the technical requirements of high manganese alloy content, high yield and low phosphorus and sulfur impurity content are met.

Example 3

The steel-making method of the high manganese steel for the low-temperature environment comprises the working procedures of electric furnace steel-making, LF refining furnace refining and VD furnace refining, and the specific process steps are as follows:

(1) an electric furnace steelmaking process: the electric furnace steelmaking comprises electric furnace charging, smelting power supply, steelmaking oxygen blowing process, slag charge adding and steel tapping;

a. when the electric furnace is charged, the charging proportion of molten iron is 37 percent, and the balance is scrap steel;

b. smelting and supplying power, wherein a medium power supply voltage of 600-700 KV is adopted during arc starting, an arc is shielded after the arc is electrified for 1.5min, the 1000KW maximum power supply is used for accelerating melting, and when 68% of scrap steel is melted, the power supply power is reduced to 700-800 KW for continuous power supply and temperature rise melting;

c. in the steelmaking oxygen blowing process, the initial oxygen blowing period is 3-5 min from the beginning of oxygen blowing, the oxygen lance is selected to be in a burner mode, scrap steel around the oxygen lance is rapidly heated, the middle oxygen blowing period is 6-15 min, the oxygen lance blows oxygen in a supersonic speed mode to finish molten steel decarburization and stirring tasks, the later oxygen blowing period is 16-18 min, carbon powder of 5kg/t steel is blown into a molten pool according to the condition of foamed slag, submerged arc operation is carried out, the utilization rate of electric energy is improved, and the heat transfer rate is accelerated;

d. adding slag materials, wherein in the melting period of each basket of materials, lime is added for slagging after power is transmitted for 4min, the total amount of added lime is 27kg/t steel, 70 percent of the total amount of lime is added in the melting period, 30 percent of lime is added after sampling and slag flowing, and light-burned dolomite is added according to the condition of slag to increase the MgO content in the slag to 6 percent;

e. tapping steel from an electric furnace, opening a ladle bottom argon blowing valve, opening a tap hole inserting plate with argon flow of 55NL/min, and starting tapping, wherein the tapping amount controls 76% of the total planned smelting amount, and the molten steel P: 0.004%, during tapping, the tilting angle of the furnace body is 40 degrees, so that smooth and stable tapping is ensured, the tapping counter and the steel flow are closely observed, the furnace body is tilted immediately when the tapping amount is reached, the argon is ensured to be smooth after tapping, the argon flow is kept, and slag-free tapping is ensured;

(2) and (3) refining process of an LF refining furnace: the LF refining furnace refining comprises seat ladle heating, refining for making white slag, deoxidizing and desulfurizing and adding alloy;

heating an LF refining ladle, blowing argon to measure temperature after the LF refining ladle, wherein the argon flow is 80NL/min, carrying out power transmission heating according to the temperature condition, and carrying out power transmission heating for 22min to 1590 ℃;

b. refining to produce white slag, wherein in the refining and heating process, 10kg/t of steel carbon powder is added for pre-deoxidation, 3kg/t of steel lime and 2.0kg/t of steel fluorite are added for primary submerged arc slagging, 4kg/t of steel ferrosilicon is added for deoxidation, 3.0kg/t of steel calcium carbide auxiliary submerged arc is added in front of a furnace, the process slag condition is rare and proper, the submerged arc is better, and the white slag is kept all the time;

c. and (3) deoxidizing and desulfurizing, wherein when the temperature of molten steel rises to 1590 ℃, power transmission is stopped, a 0.7kg/t steel Al wire is fed, deoxidizing and desulfurizing are carried out, meanwhile, the flow of argon is adjusted to 550NL/min, large argon is fully stirred and desulfurized, and the end point O: 0.0025%, S: 0.002%;

d. adding alloy, namely adding manganese alloy after white slag is formed in refining slag, adding 19kg/t of steel manganese alloy each time, then feeding power, raising the temperature and melting the alloy, adding the manganese alloy after the manganese alloy is completely melted, feeding power, raising the temperature and melting, and continuously adding the manganese alloy in such a way to meet the component requirement;

(3) and a VD furnace refining process: the VD furnace refining comprises fine adjustment of molten steel components, vacuumizing treatment, argon control and soft blowing after air breaking;

a. the preparation before vacuumizing, after the molten steel is subjected to LF refining treatment, the component temperature meets the requirement, the steel slag is good in deoxidation and fluidity, the free space of the liquid level of a steel ladle is 900mm, and the good argon blowing at the bottom of the steel ladle is ensured;

b. fine adjustment of molten steel components to enable the molten steel components to meet internal control requirements;

c. vacuumizing, wherein the vacuum degree is 66Pa, and the vacuum retention time is 12 min;

d. argon control, wherein large argon is adopted 4min before vacuum maintenance, the argon flow is 220NL/min, the argon is reduced to a soft blowing state in the later period of vacuum maintenance, and the argon flow is 60 NL/min;

e. and (3) soft blowing is carried out after the air is broken, soft blowing is carried out for 12min after the vacuum is finished, the argon flow in the soft blowing process is 40NL/min, meanwhile, the carbonized rice hulls are added on the slag surface to prevent the molten steel from sucking air, and the steel is poured by a ladle.

The molten steel produced by the high manganese steel making method in the low-temperature environment of the embodiment comprises the following steps: mn: 23.5%, P: 0.005%, S: 0.002 percent and 97 percent of manganese alloy yield, and meets the technical requirements of high manganese alloy content, high yield and low phosphorus and sulfur impurity content.

Example 4

The steel-making method of the high manganese steel for the low-temperature environment comprises the working procedures of electric furnace steel-making, LF refining furnace refining and VD furnace refining, and the specific process steps are as follows:

(1) an electric furnace steelmaking process: the electric furnace steelmaking comprises electric furnace charging, smelting power supply, steelmaking oxygen blowing process, slag charge adding and steel tapping;

a. when the electric furnace is charged, the charging proportion of molten iron is 39%, and the balance is scrap steel;

b. smelting and supplying power, wherein 610KV medium power supply voltage is adopted during arc starting, an arc is shielded after the arc is electrified for 1.8min, 1000KW maximum power supply power is used for accelerating melting, and when 66% of scrap steel is melted, the power supply power is reduced to 720KW for continuous power supply, temperature rise and melting are carried out;

c. in the steelmaking oxygen blowing process, the initial oxygen blowing period is 3-5 min from the beginning of oxygen blowing, the oxygen lance is selected to be in a burner mode, scrap steel around the oxygen lance is rapidly heated, the middle oxygen blowing period is 6-15 min, the oxygen lance blows oxygen in a supersonic speed mode to finish molten steel decarburization and stirring tasks, the later oxygen blowing period is 16-18 min, carbon powder of 6kg/t steel is blown to a molten pool according to the condition of foamed slag, submerged arc operation is carried out, the utilization rate of electric energy is improved, and the heat transfer rate is accelerated;

d. adding slag materials, wherein in the melting period of each basket of materials, lime is added for slagging after power is supplied for 4.3min, the total amount of added lime is 29kg/t steel, 70 percent of the total amount of lime is added in the melting period, 30 percent of lime is added after sampling and slag flowing, and light-burned dolomite is added according to the condition of slag to increase the MgO content in the slag to 6 percent;

e. tapping steel from an electric furnace, opening a ladle bottom argon blowing valve, opening a tap hole inserting plate with argon flow of 50NL/min, starting tapping, controlling the total planned smelting amount by the tapping amount to be 77%, and adding molten steel P: 0.0035 percent, during tapping, the tilting angle of the furnace body is 30 degrees, the smooth and stable tapping is ensured, the tapping counter and the steel flow are closely observed, the furnace body is tilted immediately when the tapping amount is reached, the argon is ensured to be smooth after tapping, the argon flow is kept, and the slag-free tapping is ensured;

(2) and (3) refining process of an LF refining furnace: the LF refining furnace refining comprises seat ladle heating, refining for making white slag, deoxidizing and desulfurizing and adding alloy;

heating an LF refining ladle, blowing argon to measure temperature after the LF refining ladle, wherein the argon flow is 90NL/min, carrying out power transmission heating according to the temperature condition, and carrying out power transmission heating for 24min to 1585 ℃;

b. refining to produce white slag, wherein in the refining and heating process, 10kg/t of steel carbon powder is added for pre-deoxidation, 4kg/t of steel lime and 1.8kg/t of steel fluorite are added for primary submerged arc slagging, 4kg/t of steel ferrosilicon is added for deoxidation, 2.0kg/t of steel calcium carbide auxiliary submerged arc is added in front of a furnace, the process slag condition is dilute and suitable, the submerged arc is better, and the white slag is kept all the time;

c. and (3) deoxidizing and desulfurizing, wherein when the temperature of the molten steel is increased to 1585 ℃, the Al wire of 0.8kg/t steel is stopped feeding by power transmission, deoxidizing and desulfurizing are carried out, meanwhile, the flow of argon is adjusted to 520NL/min, the large argon is fully stirred and desulfurized, and the end point O: 0.0020%, S: 0.001 percent;

d. adding alloy, namely adding manganese alloy after white slag is formed in refining slag, adding 18kg/t of steel manganese alloy each time, then feeding power, raising the temperature and melting the alloy, adding the manganese alloy after the manganese alloy is completely melted, feeding power, raising the temperature and melting, and continuously adding the manganese alloy in such a way to meet the component requirement;

(3) and a VD furnace refining process: the VD furnace refining comprises fine adjustment of molten steel components, vacuumizing treatment, argon control and soft blowing after air breaking;

a. the preparation before vacuumizing, after the molten steel is subjected to LF refining treatment, the component temperature meets the requirement, the steel slag is good in deoxidation and good in fluidity, the free space of the liquid level of the steel ladle is 950mm, and the good argon blowing at the bottom of the steel ladle is ensured;

b. fine adjustment of molten steel components to enable the molten steel components to meet internal control requirements;

c. vacuumizing, wherein the vacuum degree is 62Pa, and the vacuum maintaining time is 10.5 min;

d. argon control, wherein large argon is adopted 4min before vacuum maintenance, the argon flow is 230NL/min, the argon is reduced to a soft blowing state in the later period of vacuum maintenance, and the argon flow is 70 NL/min;

e. and (3) soft blowing is carried out after the air is broken, soft blowing is carried out for 14min after the vacuum is finished, the argon flow in the soft blowing process is 35NL/min, meanwhile, the carbonized rice hulls are added on the slag surface to prevent the molten steel from sucking air, and the steel is poured by a ladle.

The molten steel produced by the high manganese steel making method in the low-temperature environment of the embodiment comprises the following steps: mn: 25%, P: 0.004%, S: 0.001 percent and the manganese alloy yield is 98 percent, and the technical requirements of high manganese alloy content, high yield and low phosphorus and sulfur impurity content are met.

Example 5

The steel-making method of the high manganese steel for the low-temperature environment comprises the working procedures of electric furnace steel-making, LF refining furnace refining and VD furnace refining, and the specific process steps are as follows:

(1) an electric furnace steelmaking process: the electric furnace steelmaking comprises electric furnace charging, smelting power supply, steelmaking oxygen blowing process, slag charge adding and steel tapping;

a. when the electric furnace is charged, the charging proportion of molten iron is 36 percent, and the balance is scrap steel;

b. smelting and supplying power, wherein 680KV medium power supply voltage is adopted during arc striking, electric arc is shielded after 1.6min of electrification, 1000KW maximum power supply is used for accelerating melting, power supply power is reduced to 770KW when the scrap steel is melted by 69%, and power supply is continuously supplied, temperature is raised and melting is carried out;

c. in the steelmaking oxygen blowing process, the initial oxygen blowing period is 3-5 min from the beginning of oxygen blowing, the oxygen lance is selected to be in a burner mode, scrap steel around the oxygen lance is rapidly heated, the middle oxygen blowing period is 6-15 min, the oxygen lance blows oxygen in a supersonic speed mode to finish molten steel decarburization and stirring tasks, the later oxygen blowing period is 16-18 min, carbon powder of 7kg/t steel is blown to a molten pool according to the condition of foamed slag, submerged arc operation is carried out, the utilization rate of electric energy is improved, and the heat transfer rate is accelerated;

d. adding slag materials, wherein in the melting period of each basket of materials, lime is added for slagging after power is supplied for 4.5min, the total amount of added lime is 26kg/t steel, 70 percent of the total amount of lime is added in the melting period, 30 percent of lime is added after sampling and slag flowing, and light-burned dolomite is added according to the condition of slag to increase the MgO content in the slag to 7 percent;

e. tapping steel from an electric furnace, opening a ladle bottom argon blowing valve, opening a tap hole inserting plate with argon flow of 50NL/min, starting tapping, controlling the tapping amount to be 76.5% of the total planned smelting amount, and adding molten steel P: 0.0045 percent, the tilting angle of the furnace body is 30 degrees when tapping, which ensures smooth and steady tapping, the tapping counter and the steel flow are closely observed, the furnace body is immediately tilted when the tapping amount is reached, the argon is confirmed to be smooth after tapping, the argon flow is kept, and the slag-free tapping is ensured;

(2) and (3) refining process of an LF refining furnace: the LF refining furnace refining comprises seat ladle heating, refining for making white slag, deoxidizing and desulfurizing and adding alloy;

heating an LF refining ladle, blowing argon to measure temperature after the LF refining ladle, wherein the argon flow is 80NL/min, carrying out power transmission heating according to the temperature condition, and carrying out power transmission heating for 21min to 1595 ℃;

b. refining to produce white slag, wherein in the refining and heating process, 8kg/t of steel carbon powder is added for pre-deoxidation, 3.5kg/t of steel lime and 1.8kg/t of steel fluorite are added for primary submerged arc slagging, 3kg/t of steel ferrosilicon is added for deoxidation, 2.5kg/t of steel calcium carbide auxiliary submerged arc is added in front of a furnace, the process slag condition is rare and proper, the submerged arc is better, and the white slag is kept all the time;

c. and (3) deoxidizing and desulfurizing, wherein when the temperature of the molten steel rises to 1595 ℃, the feeding of 0.7kg/t steel Al wire is stopped to perform deoxidizing and desulfurizing, meanwhile, the flow of argon is adjusted to 570NL/min, the large argon is fully stirred and desulfurized, and the end point O: 0.0025%, S: 0.003%;

d. adding alloy, namely adding manganese alloy after white slag is formed in refining slag, adding 19kg/t of steel manganese alloy each time, then feeding power, raising the temperature and melting the alloy, adding the manganese alloy after the manganese alloy is completely melted, feeding power, raising the temperature and melting, and continuously adding the manganese alloy in such a way to meet the component requirement;

(3) and a VD furnace refining process: the VD furnace refining comprises fine adjustment of molten steel components, vacuumizing treatment, argon control and soft blowing after air breaking;

a. the preparation before vacuumizing, after the molten steel is subjected to LF refining treatment, the component temperature meets the requirement, the steel slag is good in deoxidation and good in fluidity, and the free space of the liquid level of a steel ladle is 850mm, so that good argon blowing at the bottom of the steel ladle is ensured;

b. fine adjustment of molten steel components to enable the molten steel components to meet internal control requirements;

c. vacuumizing, wherein the vacuum degree is 60Pa, and the vacuum retention time is 11.5 min;

d. argon control, wherein large argon is adopted 4min before vacuum maintenance, the argon flow is 210NL/min, the argon is reduced to a soft blowing state in the later period of vacuum maintenance, and the argon flow is 65 NL/min;

e. and (3) soft blowing is carried out after the air is broken, soft blowing is carried out for 11min after the vacuum is finished, the argon flow in the soft blowing process is 45NL/min, meanwhile, the carbonized rice hulls are added on the slag surface to prevent the molten steel from sucking air, and the steel is poured by a ladle.

The molten steel produced by the high manganese steel making method in the low-temperature environment of the embodiment comprises the following steps: mn: 24.5%, P: 0.005%, S: 0.003 percent and the manganese alloy yield is 96 percent, and meets the technical requirements of high manganese alloy content, high yield and low phosphorus and sulfur impurity content.

Example 6

The steel-making method of the high manganese steel for the low-temperature environment comprises the working procedures of electric furnace steel-making, LF refining furnace refining and VD furnace refining, and the specific process steps are as follows:

(1) an electric furnace steelmaking process: the electric furnace steelmaking comprises electric furnace charging, smelting power supply, steelmaking oxygen blowing process, slag charge adding and steel tapping;

a. when the electric furnace is charged, the charging proportion of molten iron is 38 percent, and the balance is scrap steel;

b. smelting and supplying power, wherein 660KV medium power supply voltage is adopted during arc starting, an arc is shielded after the arc is electrified for 1.2min, 1000KW maximum power supply power is used for accelerating melting, and when 67% of scrap steel is melted, the power supply power is reduced to 750KW for continuous power supply and temperature rise melting;

c. in the steelmaking oxygen blowing process, the initial oxygen blowing period is 3-5 min from the beginning of oxygen blowing, the oxygen lance is selected to be in a burner mode, scrap steel around the oxygen lance is rapidly heated, the middle oxygen blowing period is 6-15 min, the oxygen lance blows oxygen in a supersonic speed mode to finish molten steel decarburization and stirring tasks, the later oxygen blowing period is 16-18 min, carbon powder of 6kg/t steel is blown to a molten pool according to the condition of foamed slag, submerged arc operation is carried out, the utilization rate of electric energy is improved, and the heat transfer rate is accelerated;

d. adding slag materials, wherein in the melting period of each basket of materials, lime is added for slagging after power is supplied for 3.5min, the total amount of added lime is 28kg/t steel, 70 percent of the total amount of lime is added in the melting period, 30 percent of lime is added after sampling and slag flowing, and light-burned dolomite is added according to the condition of slag to increase the MgO content in the slag to 7 percent;

e. tapping steel from an electric furnace, opening a ladle bottom argon blowing valve, opening a tap hole inserting plate with argon flow of 50NL/min, starting tapping, controlling the tapping amount to be 77.5% of the total planned smelting amount, and adding molten steel P: 0.002%, during tapping, the tilting angle of the furnace body is 15 degrees, so that smooth and stable tapping is ensured, the tapping counter and the steel flow are closely observed, the furnace body is immediately tilted when the tapping amount is reached, the argon is ensured to be smooth after tapping, the argon flow is kept, and slag-free tapping is ensured;

(2) and (3) refining process of an LF refining furnace: the LF refining furnace refining comprises seat ladle heating, refining for making white slag, deoxidizing and desulfurizing and adding alloy;

heating an LF refining ladle, blowing argon to measure temperature after the LF refining ladle, wherein the argon flow is 90NL/min, carrying out power transmission heating according to the temperature condition, and carrying out power transmission heating for 23min to 1582 ℃;

b. refining to produce white slag, wherein in the refining and heating process, 9kg/t of steel carbon powder is added for pre-deoxidation, 3kg/t of steel lime and 1.5kg/t of steel fluorite are added for primary submerged arc slagging, 4.3kg/t of steel ferrosilicon is added for deoxidation, 2.8kg/t of steel calcium carbide auxiliary submerged arc is added in front of a furnace, the slag condition in the process is rare and proper, the submerged arc is better, and the white slag is kept all the time;

c. and (3) deoxidizing and desulfurizing, wherein when the temperature of the molten steel is increased to 1582 ℃, the Al wire of 0.9kg/t steel is fed in by stopping power transmission, deoxidizing and desulfurizing are carried out, meanwhile, the flow of argon is adjusted to 540NL/min, the large argon is fully stirred and desulfurized, and the end point O: 0.0030%, S: 0.002%;

d. adding alloy, namely adding manganese alloy after white slag is formed in refining slag, adding 18kg/t of steel manganese alloy each time, then feeding power, raising the temperature and melting the alloy, adding the manganese alloy after the manganese alloy is completely melted, feeding power, raising the temperature and melting, and continuously adding the manganese alloy in such a way to meet the component requirement;

(3) and a VD furnace refining process: the VD furnace refining comprises fine adjustment of molten steel components, vacuumizing treatment, argon control and soft blowing after air breaking;

a. the preparation before vacuumizing, after the molten steel is subjected to LF refining treatment, the component temperature meets the requirement, the steel slag is good in deoxidation and fluidity, the free space of the liquid level of a steel ladle is 980mm, and the good argon blowing at the bottom of the steel ladle is ensured;

b. fine adjustment of molten steel components to enable the molten steel components to meet internal control requirements;

c. vacuumizing, wherein the vacuum degree is 55Pa, and the vacuum retention time is 13 min;

d. argon control, wherein large argon is adopted 5min before vacuum maintaining, the argon flow is 225NL/min, the argon is reduced to a soft blowing state in the later period of vacuum maintaining, and the argon flow is 55 NL/min;

e. and (3) soft blowing is carried out after the air is broken, soft blowing is carried out for 13min after the vacuum is finished, the argon flow in the soft blowing process is 32NL/min, meanwhile, the carbonized rice hulls are added on the slag surface to prevent the molten steel from sucking air, and the steel is poured by a ladle.

The molten steel produced by the high manganese steel making method in the low-temperature environment of the embodiment comprises the following steps: mn: 25.5%, P: 0.006%, S: 0.002 percent and 97 percent of manganese alloy yield, and meets the technical requirements of high manganese alloy content, high yield and low phosphorus and sulfur impurity content.

Example 7

The steel-making method of the high manganese steel for the low-temperature environment comprises the working procedures of electric furnace steel-making, LF refining furnace refining and VD furnace refining, and the specific process steps are as follows:

(1) an electric furnace steelmaking process: the electric furnace steelmaking comprises electric furnace charging, smelting power supply, steelmaking oxygen blowing process, slag charge adding and steel tapping;

a. when the electric furnace is charged, the charging proportion of molten iron is 36.5 percent, and the balance is scrap steel;

b. smelting and supplying power, wherein a medium power supply voltage of 600KV is adopted during arc starting, an arc is shielded after the arc is electrified for 1.7min, the melting is accelerated by using the maximum power supply power of 1000KW, and when the scrap steel is melted by 66.8%, the power supply power is reduced to 800KW for continuous power supply, temperature rise and melting are carried out;

c. in the steelmaking oxygen blowing process, the initial oxygen blowing period is 3-5 min from the beginning of oxygen blowing, the oxygen lance is selected to be in a burner mode, scrap steel around the oxygen lance is rapidly heated, the middle oxygen blowing period is 6-15 min, the oxygen lance blows oxygen in a supersonic speed mode to finish molten steel decarburization and stirring tasks, the later oxygen blowing period is 16-18 min, carbon powder of 5kg/t steel is blown into a molten pool according to the condition of foamed slag, submerged arc operation is carried out, the utilization rate of electric energy is improved, and the heat transfer rate is accelerated;

d. adding slag materials, wherein in the melting period of each basket of materials, lime is added for slagging after power is transmitted for 4.5min, the total amount of added lime is 27.2kg/t steel, 70 percent of the total amount of lime is added in the melting period, 30 percent of lime is added after sampling and slag flowing, and light-burned dolomite is added according to the condition of slag to increase the MgO content in the slag to 8 percent;

e. tapping steel from an electric furnace, opening a ladle bottom argon blowing valve, opening a tap hole inserting plate with argon flow of 60NL/min, starting tapping, controlling the tapping amount to be 75.5% of the total planned smelting amount, and adding molten steel P: 0.0025 percent, when tapping, the tilting angle of the furnace body is 40 degrees, ensuring smooth and stable tapping, closely observing a tapping counter and steel flow, immediately tilting the furnace body when the tapping amount is reached, confirming the smoothness of argon after tapping, keeping the flow of argon and ensuring slag-free tapping;

(2) and (3) refining process of an LF refining furnace: the LF refining furnace refining comprises seat ladle heating, refining for making white slag, deoxidizing and desulfurizing and adding alloy;

heating an LF refining ladle, blowing argon to measure temperature after the LF refining ladle, wherein the argon flow is 100NL/min, carrying out power transmission heating according to the temperature condition, wherein the power transmission heating time is 23.5min, and the heating is carried out to 1597 ℃;

b. refining to produce white slag, wherein in the refining and heating process, 9kg/t of steel carbon powder is added for pre-deoxidation, 4kg/t of steel lime and 2.0kg/t of steel fluorite are added for primary submerged arc slagging, 5kg/t of steel ferrosilicon is added for deoxidation, 2.0kg/t of steel calcium carbide auxiliary submerged arc is added in front of a furnace, the process slag condition is dilute and suitable, the submerged arc is better, and the white slag is kept all the time;

c. and (3) deoxidizing and desulfurizing, wherein when the temperature of molten steel is increased to 1597 ℃, power transmission is stopped, 0.8kg/t of steel Al wire is fed, deoxidizing and desulfurizing are carried out, meanwhile, the flow of argon is adjusted to 580NL/min, large argon is fully stirred and desulfurized, and the end point O: 0.0020%, S: 0.001 percent;

d. adding alloy, namely adding manganese alloy after white slag is formed in refining slag, adding 20kg/t of steel manganese alloy each time, then feeding power, raising the temperature and melting the alloy, adding the manganese alloy after the manganese alloy is completely melted, and feeding power, raising the temperature and melting the manganese alloy, wherein the manganese alloy is continuously added in such a way to meet the component requirement;

(3) and a VD furnace refining process: the VD furnace refining comprises fine adjustment of molten steel components, vacuumizing treatment, argon control and soft blowing after air breaking;

a. the preparation before vacuumizing, after the molten steel is subjected to LF refining treatment, the component temperature meets the requirement, the steel slag is good in deoxidation and good in fluidity, and the free space of the liquid level of a steel ladle is 830mm, so that the good argon blowing at the bottom of the steel ladle is ensured;

b. fine adjustment of molten steel components to enable the molten steel components to meet internal control requirements;

c. vacuumizing, wherein the vacuum degree is 58Pa, and the vacuum retention time is 15 min;

d. argon control, wherein large argon is adopted 4min before vacuum maintenance, the argon flow is 215NL/min, the argon is reduced to a soft blowing state in the later period of vacuum maintenance, and the argon flow is 75 NL/min;

e. and (3) soft blowing is carried out after the air is broken, soft blowing is carried out for 12.5min after the vacuum is finished, the argon flow in the soft blowing process is 38NL/min, meanwhile, the carbonized rice hulls are added on the slag surface to prevent the molten steel from sucking air, and the steel is poured by a ladle.

The molten steel produced by the high manganese steel making method in the low-temperature environment of the embodiment comprises the following steps: mn: 26%, P: 0.004%, S: 0.001 percent and the manganese alloy yield is 98 percent, and the technical requirements of high manganese alloy content, high yield and low phosphorus and sulfur impurity content are met.

Example 8

The steel-making method of the high manganese steel for the low-temperature environment comprises the working procedures of electric furnace steel-making, LF refining furnace refining and VD furnace refining, and the specific process steps are as follows:

(1) an electric furnace steelmaking process: the electric furnace steelmaking comprises electric furnace charging, smelting power supply, steelmaking oxygen blowing process, slag charge adding and steel tapping;

a. when the electric furnace is charged, the charging proportion of molten iron is 38.2 percent, and the balance is scrap steel;

b. smelting and supplying power, wherein 700KV medium power supply voltage is adopted during arc starting, the arc is shielded after being electrified for 1.3min, 1000KW maximum power supply is used for accelerating melting, and when 67.5% of scrap steel is melted, the power supply power is reduced to 700KW for continuous power supply and temperature rise melting;

c. in the steelmaking oxygen blowing process, the initial oxygen blowing period is 3-5 min from the beginning of oxygen blowing, the oxygen lance is selected to be in a burner mode, scrap steel around the oxygen lance is rapidly heated, the middle oxygen blowing period is 6-15 min, the oxygen lance blows oxygen in a supersonic speed mode to finish molten steel decarburization and stirring tasks, the later oxygen blowing period is 16-18 min, carbon powder of 8kg/t steel is blown into a molten pool according to the condition of foamed slag, submerged arc operation is carried out, the utilization rate of electric energy is improved, and the heat transfer rate is accelerated;

d. adding slag materials, wherein in the melting period of each basket of materials, lime is added for slagging after power is supplied for 3.8min, the total amount of added lime is 29.3kg/t steel, 70 percent of the total amount of lime is added in the melting period, 30 percent of lime is added after sampling and slag flowing, and light-burned dolomite is added according to the condition of slag to increase the MgO content in the slag to 7 percent;

e. tapping steel from an electric furnace, opening a ladle bottom argon blowing valve, opening a tap hole inserting plate with argon flow of 55NL/min, starting tapping, controlling the tapping amount to be 77.4% of the total planned smelting amount, and adding molten steel P: 0.0042 percent, the tilting angle of the furnace body is 30 degrees when tapping, which ensures smooth and steady tapping, the tapping counter and the steel flow are closely observed, the furnace body is immediately tilted when the tapping amount is reached, the argon is confirmed to be smooth after tapping, the argon flow is kept, and the slag-free tapping is ensured;

(2) and (3) refining process of an LF refining furnace: the LF refining furnace refining comprises seat ladle heating, refining for making white slag, deoxidizing and desulfurizing and adding alloy;

heating an LF refining ladle, blowing argon to measure temperature after the LF refining ladle, wherein the argon flow is 80NL/min, carrying out power transmission heating according to the temperature condition, wherein the power transmission heating time is 25min, and the heating is carried out to 1588 ℃;

b. refining to produce white slag, wherein in the refining and heating process, 9kg/t of steel carbon powder is added for pre-deoxidation, 3kg/t of steel lime and 1.7kg/t of steel fluorite are added for primary submerged arc slagging, 4kg/t of steel ferrosilicon is added for deoxidation, 2.0kg/t of steel calcium carbide auxiliary submerged arc is added in front of a furnace, the process slag condition is dilute and suitable, the submerged arc is better, and the white slag is kept all the time;

c. and (3) deoxidizing and desulfurizing, wherein when the temperature of the molten steel is increased to 1588 ℃, the Al wire of 0.7kg/t steel is stopped feeding by power transmission, deoxidizing and desulfurizing are carried out, meanwhile, the flow of argon is adjusted to 530NL/min, the large argon is fully stirred and desulfurized, and the end point O: 0.0025%, S: 0.003%;

d. adding alloy, namely adding manganese alloy after white slag is formed in refining slag, adding 18kg/t of steel manganese alloy each time, then feeding power, raising the temperature and melting the alloy, adding the manganese alloy after the manganese alloy is completely melted, feeding power, raising the temperature and melting, and continuously adding the manganese alloy in such a way to meet the component requirement;

(3) and a VD furnace refining process: the VD furnace refining comprises fine adjustment of molten steel components, vacuumizing treatment, argon control and soft blowing after air breaking;

a. the preparation before vacuumizing, after the molten steel is subjected to LF refining treatment, the component temperature meets the requirement, the steel slag is good in deoxidation and good in fluidity, the free space of the liquid level of a steel ladle is 880mm, and the good argon blowing at the bottom of the steel ladle is ensured;

b. fine adjustment of molten steel components to enable the molten steel components to meet internal control requirements;

c. vacuumizing, wherein the vacuum degree is 50Pa, and the vacuum retention time is 14 min;

d. argon control, wherein large argon is adopted 4min before vacuum maintenance, the argon flow is 235NL/min, the argon is reduced to a soft blowing state in the later period of vacuum maintenance, and the argon flow is 58 NL/min;

e. and (3) soft blowing is carried out after the air is broken, soft blowing is carried out for 13.5min after the vacuum is finished, the argon flow in the soft blowing process is 43NL/min, meanwhile, the carbonized rice hulls are added on the slag surface to prevent the molten steel from sucking air, and the steel is poured by a ladle.

The molten steel produced by the high manganese steel making method in the low-temperature environment of the embodiment comprises the following steps: mn: 22.5%, P: 0.006%, S: 0.003 percent and the manganese alloy yield is 96 percent, and meets the technical requirements of high manganese alloy content, high yield and low phosphorus and sulfur impurity content.

Although the present invention has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that: modifications and equivalents may be made thereto without departing from the spirit and scope of the invention and it is intended to cover in the claims the invention as defined in the appended claims.

Claims (7)

1. A steel-making method of high manganese steel used in low temperature environment is characterized in that the steel-making method comprises the working procedures of electric furnace steel-making, LF refining furnace refining and VD furnace refining, and the specific process steps are as follows:

(1) an electric furnace steelmaking process: the electric furnace steelmaking comprises electric furnace charging, smelting power supply, steelmaking oxygen blowing process, slag charge adding and steel tapping;

a. when an electric furnace is charged, controlling the charging proportion of molten iron according to 35-40%, and taking the rest as scrap steel;

b. smelting and supplying power, wherein medium voltage is adopted during arc striking, electric arc is shielded after the arc is electrified for 1-2 min, the maximum power supply power is used for accelerating melting, and when scrap steel is melted by 65-70%, the power supply power is reduced to continuously supply power and increase the temperature for melting;

c. in the steelmaking oxygen blowing process, the initial oxygen blowing period is 3-5 min from the beginning of oxygen blowing, the oxygen lance is selected to be in a burner mode, scrap steel around the oxygen lance is rapidly heated, the middle oxygen blowing period is 6-15 min, the oxygen lance blows oxygen in a supersonic speed mode to finish molten steel decarburization and stirring tasks, the later oxygen blowing period is 16-18 min, carbon powder of 5-8 kg/t steel is blown into a molten pool according to the condition of foamed slag, submerged arc operation is carried out, the electric energy utilization rate is improved, and the heat transfer rate is accelerated;

d. adding slag materials, wherein in the melting period of each basket of materials, lime is added for slagging after power is transmitted for 3-5 min, the total amount of added lime is 25-30 kg/t steel, 70% of the total amount of lime is added in the melting period, lime with the total amount of 30% is added after sampling and slag flowing, light-burned dolomite is added according to the condition of slag to increase the MgO content in the slag to 6-8%, and if the effect of foamed slag is poor, the carbon can be sprayed for adjustment;

e. tapping by an electric furnace, wherein molten steel components and temperature at the tapping end point meet requirements, opening an argon blowing valve at the bottom of a ladle, enabling argon flow to be 50-60 NL/min, opening a tapping hole inserting plate, starting tapping, controlling the tapping amount to be 75-78% of the total planned smelting amount, enabling the molten steel P to be less than or equal to 0.005%, enabling the inclination angle of a furnace body to be 15-40 degrees during tapping, ensuring smooth and stable tapping, closely observing a tapping counter and the steel flow, immediately tilting the furnace body when the planned tapping amount or the slag discharge amount is reached, confirming that argon is smooth after tapping, keeping the argon flow, and ensuring slag-free tapping;

(2) and (3) refining process of an LF refining furnace: the LF refining furnace refining comprises seat ladle heating, refining for making white slag, deoxidizing and desulfurizing and adding alloy;

heating an LF refining ladle, blowing argon to measure temperature after the LF refining ladle, wherein the flow of the argon is 80-100 NL/min, carrying out power transmission and heating according to the temperature condition, wherein the power transmission and heating time is 20-25 min, and the heating is carried out to 1580-1600 ℃;

b. refining to produce white slag, wherein in the refining and heating process, 8-10 kg/t of steel carbon powder is added for pre-deoxidation, 3-4 kg/t of steel lime and 1.5-2.0 kg/t of steel fluorite are added for primary submerged arc slagging, 3-5 kg/t of steel ferrosilicon is added for deoxidation, 2.0-3.0 kg/t of steel calcium carbide auxiliary submerged arc is added in front of a furnace, the slag condition in the process is dilute and suitable, the submerged arc is good, and the white slag is kept all the time;

c. deoxidizing and desulfurizing, wherein when the temperature of molten steel rises to 1580-1600 ℃, power transmission is stopped, 0.7-0.9 kg/t of steel Al wire is fed for deoxidizing and desulfurizing, the flow of argon is adjusted to 500-600 NL/min, the large argon is fully stirred for deoxidizing and desulfurizing, the end point O is less than or equal to 0.0030 percent, and the end point S is less than or equal to 0.003 percent;

d. adding alloy, namely starting to add manganese alloy after white slag is formed in refining slag, adding 18-20 kg/t of steel manganese alloy each time, then feeding power, raising the temperature and melting the alloy, adding the manganese alloy after the manganese alloy is completely melted, and then feeding power, raising the temperature and melting, wherein the manganese alloy is continuously added in such a way to meet the component requirement;

(3) and a VD furnace refining process: the VD furnace refining comprises fine adjustment of molten steel components, vacuumizing treatment, argon control and soft blowing after air breaking;

a. the preparation before vacuumizing, after the molten steel is subjected to LF refining treatment, the component temperature meets the requirement, the steel slag is well deoxidized and has good fluidity, the free space of the liquid level of the steel ladle is more than or equal to 800mm, and the good argon blowing at the bottom of the steel ladle is ensured;

b. fine adjustment of molten steel components to enable the molten steel components to meet internal control requirements;

c. vacuumizing, wherein the vacuum degree is less than or equal to 66.7Pa, and the vacuum retention time is more than or equal to 10 min;

d. argon is used for controlling, wherein the argon is adopted 4-5 min before vacuum maintenance, the argon flow is controlled to be 200-240 NL/min, the argon is turned to be small to be in a soft blowing state in the later period of vacuum maintenance, and the argon flow is controlled to be 50-80 NL/min;

e. and (3) soft blowing is carried out after the vacuum is broken, the soft blowing is carried out for 10-15 min after the vacuum is finished, the argon flow is controlled to be 30-50 NL/min in the soft blowing process, meanwhile, the carbonized rice hulls are added on the slag surface to prevent molten steel from sucking air, and the steel is poured by a ladle.

2. The method for producing high manganese steel for use in low temperature environments as claimed in claim 1, wherein said step (1) of charging the electric furnace with scrap steel: the alloy content is less than or equal to 2.0 percent, P is less than or equal to 0.020 percent, and S is less than or equal to 0.10 percent.

3. The steel-making method of high manganese steel for low-temperature environment according to claim 1, wherein a medium power supply voltage of 600-700 KV is firstly adopted when smelting power supply and arc striking in step (1).

4. The method for making high manganese steel used in low temperature environment according to claim 1, wherein electric arc is shielded after the smelting power supply in step (1) is electrified for 1-2 min, and the melting is accelerated by using 1000KW maximum power supply.

5. The steel-making method of high manganese steel for low-temperature environment according to claim 1, wherein when 65-70% of the smelting power supply scrap steel in the step (1) is melted, the power supply is reduced to 700-800 KW, and power supply is continuously supplied to increase the temperature for melting.

6. The method for producing high manganese steel for use in a cryogenic environment as claimed in any one of claims 1 to 5, wherein said steel-making method produces molten high manganese steel having: c: 0.35-0.55%, Si: 0.10-0.50%, Mn is more than or equal to 22.5%, P is less than or equal to 0.007%, S is less than or equal to 0.003%, Cr: 3.00-4.00%, Cu: 0.30-0.70%, and the balance of Fe and inevitable impurities.

7. The method for making high manganese steel used in low temperature environment according to any one of claims 1 to 5, wherein the molten steel of high manganese steel produced by the steel making method has Mn not less than 22.5%, manganese alloy yield not less than 96%, high purity of molten steel, low content of P, S impurity, P not more than 0.007%, S not more than 0.003%.