CN113430448A - Method for preparing low-sulfur low-nitrogen low-hydrogen steel at low cost and product thereof - Google Patents
Method for preparing low-sulfur low-nitrogen low-hydrogen steel at low cost and product thereof Download PDFInfo
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- C22C33/00—Making ferrous alloys
- C22C33/04—Making ferrous alloys by melting
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- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/0006—Adding metallic additives
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- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
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- C21C7/06—Deoxidising, e.g. killing
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- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
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- C21C7/064—Dephosphorising; Desulfurising
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- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
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- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
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- C21C7/076—Use of slags or fluxes as treating agents
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- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
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Abstract
The invention discloses a method for preparing low-sulfur low-nitrogen low-hydrogen steel at low cost, which comprises the following steps: smelting in a primary smelting furnace, vacuum refining in a VD furnace and continuous casting. The temperature of the molten steel before the smelting and tapping of the primary smelting furnace is (T)L+180 ℃) +/-10 ℃; molten steel at the end of tappingTemperature is (T)L+130 ℃) +/-10 ℃; the S% in molten steel after tapping is less than or equal to 80ppm, and the slag thickness of steel slag is less than 0.07 m; the molten steel temperature when VD enters the station is (T)L+120 ℃) +/-10 ℃; the molten steel temperature after the completion of vacuum refining in the VD furnace is (T)L+60 ℃) plus or minus 10 ℃; the temperature of the molten steel in the continuous casting tundish is (T)L+20℃)±5℃；TLIs the liquidus temperature. According to the method for preparing the low-sulfur low-nitrogen low-hydrogen steel at low cost, the contents of sulfur, hydrogen and nitrogen in the molten steel can be efficiently reduced to be below target values, the process cost is greatly reduced, the refining time is shortened, the production rhythm is accelerated, and the refining efficiency is improved.
Description
Technical Field
The invention belongs to the technical field of steelmaking, and particularly relates to a method for preparing low-sulfur low-nitrogen low-hydrogen steel with a large furnace volume VD refining process at a fast pace and low cost and a product thereof.
Background
Sulfur is generally present in molten steel as MnS inclusions. Compared with a steel substrate, the MnS inclusion has better plasticity and is easily deformed into a strip shape in the rolling process. The MnS inclusions have a very serious influence on the Z-directional performance of the steel sheet. Therefore, high quality steel grades require strict requirements for sulfur content, and the sulfur content must be controlled to 0.005% or less. In addition, MnS in the steel is a major factor in the generation of HIC and SSCC cracks under acidic environmental conditions, and it is required to control the sulfur content to 0.002% or less, even 0.0015% or less.
For medium plate steel, the contents of hydrogen and nitrogen also affect the flaw detection requirements of the steel. The lower hydrogen content can ensure the Z-direction performance of the steel grade. In some steel grades, the hydrogen content cannot be improved by means of heap cooling and the like, and the hydrogen must be removed as much as possible in the smelting stage, so that the hydrogen content is controlled below 0.0002%.
In order to meet the requirements of steel grades on the contents of sulfur, hydrogen and nitrogen, a smelting process route generally adopts LF + VD or LF + RH double refining operation. Wherein, the operations of desulfurization and temperature rise are carried out through LF refining, and degassing is carried out through RH or VD vacuum refining to ensure that the components of the molten steel meet the performance requirements. But the double refining treatment process is long in time and high in production cost.
Chinese patent CN102644018B discloses a smelting process of a medium plate blank of hydrogen induced cracking resistant pipeline steel. The process comprises the following steps: deep desulfurization is carried out by LF refining, the sulfur content in molten steel is reduced to be below 0.0010%, and gas in the steel is removed by RH vacuum refining, so that the target requirements of [ H ] less than or equal to 1.2ppm and [ N ] less than or equal to 35ppm are met. Although the method provided by the Chinese patent meets the requirements of low sulfur, low hydrogen and low nitrogen content of steel grades, the LF and RH double refining treatment is adopted, the process period is long, and the production cost is high.
Therefore, it is necessary to develop a method for preparing a low-sulfur low-nitrogen low-hydrogen steel material with a large furnace volume and a fast pace by a VD refining process at a low cost so as to efficiently reduce the contents of sulfur, hydrogen and nitrogen in molten steel to be below target values.
Disclosure of Invention
In view of the problems, the invention provides a method for preparing low-sulfur low-nitrogen low-hydrogen steel with a large furnace volume VD refining process at a fast pace and low cost and a product thereof. According to the method for preparing the low-sulfur low-nitrogen low-hydrogen steel at low cost, the contents of sulfur, hydrogen and nitrogen in the molten steel can be efficiently reduced to be below target values by controlling the temperature of the molten steel before tapping, the temperature of the molten steel after tapping, the slag amount during tapping, deoxidation and slag modification during tapping, the temperature of the molten steel during VD arrival, the VD deep vacuum treatment time during VD, the temperature of the molten steel after VD furnace vacuum refining and the temperature of the molten steel in a continuous casting tundish, and meanwhile, the process cost is greatly reduced, the refining time is reduced, the production rhythm is accelerated, and the refining efficiency is improved.
The technical scheme of the invention for realizing the purpose is as follows:
in one aspect of the present invention, there is provided a method for producing a low-sulfur, low-nitrogen, and low-hydrogen steel at low cost, comprising: smelting in a primary smelting furnace, vacuum refining in a VD furnace and continuous casting; wherein:
in the smelting process of the primary smelting furnace, the temperature of molten steel before tapping is (T)L+180 ℃) +/-10 ℃; the temperature of the molten steel after tapping is (T)L+130 ℃) +/-10 ℃; after tapping, the S% in molten steel is less than or equal to 80ppm, and the slag thickness of the steel slag is less than 0.07 m;
in the vacuum refining process of the VD furnace, the molten steel temperature when VD enters the station is (T)L+120 ℃) +/-10 ℃; the molten steel temperature after the VD furnace vacuum refining is finished is (T)L+60℃)±10℃；
In the continuous casting process, the temperature of the molten steel in the continuous casting tundish is (T)L+20℃)±5℃；
Wherein, T isLIs the liquidus temperature.
In some embodiments of the invention, in the method for preparing low-sulfur low-nitrogen low-hydrogen steel at low cost, the temperature of the inner wall of the ladle before tapping is 1050-1200 ℃ during the smelting process of the primary smelting furnace.
In some embodiments of the invention, in the method for preparing low-sulfur low-nitrogen low-hydrogen steel at low cost, the temperature of the inner wall of the ladle before tapping is 1150-1180 ℃ in the process of smelting in the primary smelting furnace.
In some embodiments of the invention, in the method for producing a low-sulfur, low-nitrogen and low-hydrogen steel product at low cost, molten steel and steel slag are deoxidized and alloyed during tapping of the molten steel during smelting in the primary smelting furnace;
the deoxidation comprises the following steps: adding aluminum into molten steel and steel slag, wherein the addition amount of the aluminum is (1.45m +0.25 a)0+1.63d-80)Kg～(1.45m+0.25a0+1.63d +50) Kg; wherein m is the weight of molten steel (unit is t); a is0The oxygen activity (unit is ppm) of molten steel before tapping of the molten steel; d is the thickness of the steel slag (unit is mm).
In some embodiments of the present invention, in the method for producing a low-sulfur, low-nitrogen and low-hydrogen steel at low cost according to the present invention, slag is added to molten steel and steel slag for slag modification during the primary smelting process after the alloying process is completed;
wherein the slag comprises: lime, light burned dolomite, and fluorite;
the additive amount of the lime is 4.0-6.0 Kg/t steel, the additive amount of the light-burned dolomite is 1.0-2.0 Kg/t steel, and the additive amount of the fluorite is 0.5-1.0 Kg/t steel.
In some embodiments of the invention, in the method for preparing low-sulfur low-nitrogen low-hydrogen steel at low cost, the vacuum treatment time of the vacuum chamber with the pressure of less than or equal to 67Pa in the vacuum refining process of the VD furnace is 8-15 min.
In some embodiments of the invention, in the method for preparing low-sulfur low-nitrogen low-hydrogen steel at low cost, during the vacuum refining process of the VD furnace, the slag steel is stirred by blowing argon with a flow rate of 1.50-3.00 NL/(min. t steel) at a large bottom.
In some embodiments of the invention, in the method for preparing low-sulfur low-nitrogen low-hydrogen steel at low cost, the mass percentage of aluminum in molten steel when VD enters a station is 0.06-0.10% in the vacuum refining process of the VD furnace.
In some embodiments of the invention, in the method for preparing low-sulfur low-nitrogen low-hydrogen steel at low cost, the sulfur content in the molten steel after the smelting in the primary smelting furnace is finished is less than or equal to 0.008 percent by mass.
In some embodiments of the present invention, in the method for producing a low-sulfur, low-nitrogen and low-hydrogen steel product at low cost according to the present invention, after the vacuum refining in the VD furnace is completed, the steel slag comprises, by mass: 55-65% of CaO and Al2O3 30～35％、MgO 6～11％、SiO2 3～6％、(FeO+MnO)<0.8％；
The total slag amount of the steel slag is 7-10 Kg/t steel.
In some embodiments of the invention, in the method for preparing low-sulfur low-nitrogen low-hydrogen steel with low cost, after the VD furnace is finished with vacuum refining, the S% in the molten steel is less than or equal to 30ppm, the hydrogen content is less than or equal to 1.5ppm, and the nitrogen content is less than or equal to 35 ppm.
In another aspect of the present invention, there is provided a steel sheet manufactured by the method for manufacturing a low-sulfur, low-nitrogen, and low-hydrogen steel material at low cost according to the present invention.
Generally speaking, the production line furnace capacity of medium steel plate is generally large, and is 150-400 tons. The temperature drop of the molten steel in the furnace volume is relatively small in each stage, the addition amount of alloy required for partial varieties of steel is small, the required heat is small, the heat of the molten steel after leaving the primary smelting furnace can meet the smelting requirement of a VD (vacuum degassing) single-link process, and VD can simultaneously realize the conditions of desulfurization and degassing.
One or more technical embodiments of the present invention have at least the following technical effects or advantages:
(1) according to the method for preparing the low-sulfur low-nitrogen low-hydrogen steel at low cost, provided by the invention, the contents of sulfur, hydrogen and nitrogen in the molten steel can be efficiently reduced to be below target values by controlling the temperature of the molten steel before tapping, the temperature of the molten steel after tapping, the slag amount in the tapping process, the modification of the molten steel and slag, the temperature of the molten steel when VD is in station, the VD deep vacuum treatment time, the temperature of the molten steel after the VD furnace is in vacuum refining and the temperature of the molten steel in a continuous casting tundish, and meanwhile, the process cost is greatly reduced, the refining time is reduced, the production rhythm is accelerated, and the refining efficiency is improved.
(2) Aiming at the purpose of the invention, through a large number of optimization balance tests, in the process of smelting in the primary smelting furnace, the method for preparing the low-sulfur low-nitrogen low-hydrogen steel at low cost reduces the temperature drop of the molten steel in the tapping process by controlling the temperature of the inner wall of the steel ladle before tapping and controlling the addition amount of aluminum in the molten steel and the steel slag, reduces the oxidability of the molten steel and the furnace slag entering VD vacuum refining, and is favorable for rapid desulfurization.
Detailed Description
The present invention will be described in detail below with reference to specific embodiments and examples, and the advantages and various effects of the present invention will be more clearly apparent therefrom. It will be understood by those skilled in the art that these specific embodiments and examples are for the purpose of illustrating the invention and are not to be construed as limiting the invention.
Throughout the specification, unless otherwise specifically noted, terms used herein should be understood as having meanings as commonly used in the art. Accordingly, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. If there is a conflict, the present specification will control.
Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.
In order to solve the technical problems, the embodiment of the invention provides the following general ideas:
in one aspect of the present invention, there is provided a method for producing a low-sulfur, low-nitrogen, and low-hydrogen steel at low cost, comprising: smelting in a primary smelting furnace, vacuum refining in a VD furnace and continuous casting; wherein:
in the smelting process of the primary smelting furnace, the temperature of molten steel before tapping is (T)L+180 ℃) +/-10 ℃; the temperature of the molten steel after tapping is (T)L+130 ℃) +/-10 ℃; after tapping, the S% in molten steel is less than or equal to 80ppm, and the slag thickness of the steel slag is less than 0.07 m;
in the vacuum refining process of the VD furnace, the molten steel temperature when VD enters the station is (T)L+120 ℃) +/-10 ℃; the molten steel temperature after the VD furnace vacuum refining is finished is (T)L+60℃)±10℃；
In the continuous casting process, the temperature of the molten steel in the continuous casting tundish is (T)L+20℃)±5℃；
Wherein, T isLIs the liquidus temperature.
In the method for preparing the low-sulfur low-nitrogen low-hydrogen steel at low cost, the sulfur content and the hydrogen and nitrogen content in the molten steel can be efficiently reduced to be lower than target values by controlling the molten steel temperature before tapping, the molten steel temperature after tapping, the slag amount during tapping, the molten steel deoxidization and slag modification during tapping, the molten steel temperature during VD (vacuum distillation) station entry, the VD deep vacuum treatment time, the molten steel temperature after VD furnace vacuum refining and the molten steel temperature in a continuous casting tundish, and the sulfur content, the hydrogen content and the nitrogen content in the molten steel can be efficiently reduced to be lower than the target valuesMeanwhile, the process cost is greatly reduced, the refining time is shortened, the production rhythm is accelerated, and the refining efficiency is improved. Wherein the temperature of molten steel in a continuous casting tundish is limited to (T)L+20 ℃) +/-5 ℃, which is beneficial to improving the cleanliness of molten steel and the quality of casting blanks.
In some embodiments of the invention, in the method for preparing the low-sulfur low-nitrogen low-hydrogen steel material at low cost, the temperature of the inner wall of the ladle before tapping is 1050-1200 ℃ in the primary smelting furnace smelting process. The temperature of the inner wall of the steel ladle before tapping is limited to 1050-1200 ℃, so that the temperature drop in the tapping process of the converter can be obviously reduced.
In some embodiments of the invention, in the method for preparing the low-sulfur low-nitrogen low-hydrogen steel material at low cost, the temperature of the inner wall of the ladle before tapping is 1150-1180 ℃ in the smelting process of the primary smelting furnace. The temperature of the inner wall of the ladle before tapping is further limited to 1150-1180 ℃, so that the temperature drop in the tapping process of the converter can be further reduced.
In some embodiments of the invention, in the method for preparing a low-sulfur, low-nitrogen and low-hydrogen steel product at low cost, molten steel and steel slag are deoxidized and alloyed during tapping of the molten steel during smelting in the primary smelting furnace;
the deoxidation comprises the following steps: adding aluminum into molten steel and steel slag, wherein the addition amount of the aluminum is (1.45m +0.25 a)0+1.63d-80)Kg～(1.45m+0.25a0+1.63d +50) Kg; wherein m is the weight of the molten steel; a is0The oxygen activity of the molten steel before tapping of the molten steel is obtained; d is the thickness of the steel slag. The inventor has found that the adding amount of aluminum is limited to (1.45m +0.25 a)0+1.63d-80)Kg～(1.45m+0.25a0+1.63d +50) Kg, it can help to maintain the oxygen in the molten steel and slag at a very low level, thus creating a good reducing atmosphere for desulfurization.
In some embodiments of the invention, in the method for preparing a low-sulfur, low-nitrogen and low-hydrogen steel material at low cost, slag is added into molten steel and steel slag for slag modification after the alloying is completed in the primary smelting process;
wherein the slag comprises: lime, light burned dolomite, and fluorite;
the additive amount of the lime is 4.0-6.0 Kg/t steel, the additive amount of the light-burned dolomite is 1.0-2.0 Kg/t steel, and the additive amount of the fluorite is 0.5-1.0 Kg/t steel. According to the invention, the addition amount of lime is limited to 4.0-6.0 Kg/t steel, the addition amount of light-burned dolomite is 1.0-2.0 Kg/t steel, and the addition amount of fluorite is 0.5-1.0 Kg/t steel, so that the refining slag with high alkalinity and good fluidity can be formed, and the desulfurization capability of the refining slag is improved.
In some embodiments of the invention, in the method for preparing low-sulfur low-nitrogen low-hydrogen steel at low cost, the vacuum chamber pressure is less than or equal to 67Pa and the vacuum treatment time is 8-15 min in the vacuum refining process of the VD furnace. The invention limits the pressure of the vacuum chamber to be less than or equal to 67Pa, and the vacuum treatment time to be 8-15 min, thereby being beneficial to fully removing sulfur, hydrogen and nitrogen in the molten steel.
In some embodiments of the invention, in the method for preparing low-sulfur low-nitrogen low-hydrogen steel at low cost, during the vacuum refining process of the VD furnace, the slag steel is stirred by blowing argon with a flow rate of 1.50-3.00 NL/(min. t steel) at a large bottom. The invention limits the amount of argon blown at the large bottom, and is beneficial to the full and rapid contact of slag steel to realize the technical effect of rapid desulfurization.
In some embodiments of the invention, in the method for preparing a low-sulfur low-nitrogen low-hydrogen steel material at low cost, the mass percentage of aluminum in molten steel when VD enters a station is 0.06-0.10% in the vacuum refining process of the VD furnace. The mass percentage of aluminum in the molten steel when VD enters the station is 0.06-0.10%, which is beneficial to keeping the molten steel and the slag in the optimal reduction state and better promoting the desulfurization reaction.
The method for producing a low-sulfur, low-nitrogen, and low-hydrogen steel at low cost according to the present application will be described in detail with reference to examples, comparative examples, and experimental data.
Example 1:
in the present example, steel grade L245DP was selected, tap quantity 213t, liquidus temperature 1516 ℃ and oxygen activity a0580 ppm; the slag thickness d of the steel slag is 0.04m, the slag discharging thickness is 0.01m, and the thickness of the added slag is 0.03 m; the adopted processes are primary smelting furnace smelting, VD furnace vacuum refining and continuous casting.
Specifically, the method for preparing a low-sulfur low-nitrogen low-hydrogen steel material at low cost in this embodiment includes:
(1) primary smelting in a converter: the steel ladle is baked on line by adopting normal turnover, and the temperature of molten steel before tapping is 1698 ℃; the temperature of the molten steel after tapping is 1650 ℃; after tapping, the S% in the molten steel is 46ppm, and the slag thickness of the steel slag is 0.04 m; the temperature of the inner wall of the steel ladle before tapping is 1050 ℃; deoxidizing and alloying the molten steel and the steel slag in the process of tapping the molten steel; deoxygenation, comprising: adding aluminum into molten steel and steel slag, wherein the adding amount of the aluminum is 566 Kg; after the alloying is finished, slag charge is added for modifying the slag, wherein the addition amount of lime is 5.0Kg/t steel, the addition amount of light-burned dolomite is 1.0Kg/t steel, and the addition amount of fluorite is 0.5Kg/t steel.
(2) Vacuum refining in a VD furnace: the temperature of molten steel when VD enters the station is 1630 ℃; the temperature of the molten steel after the VD furnace vacuum refining is finished is 1575 ℃; the pressure of the vacuum chamber is less than or equal to 67Pa, and the vacuum treatment time is 8 min; when VD enters the station, the mass percent of aluminum in the molten steel is 0.079%; stirring the slag steel by adopting the large-bottom argon blowing amount with the flow rate of 1.50NL/(min t steel); after the vacuum refining of the VD furnace is finished, the steel slag comprises the following components in percentage by mass: CaO 58.25%, Al2O3 29.46％、MgO 7.13％、SiO23.17% and (FeO + MnO) 0.56%; the total slag amount of the steel slag is 7.5Kg/t steel. After completion of the vacuum refining in the VD furnace, the S% in the molten steel was 19ppm, the hydrogen content was 1.23ppm, and the nitrogen content was 28 ppm.
(3) Continuous casting: the temperature of the tundish is 1536 ℃, and the casting blank with the section of 250mm multiplied by 2400mm is cast by continuous casting.
Example 2:
in the embodiment, the steel grade Q345DH is selected, the steel tapping amount is 302t, the liquidus temperature is 1517 ℃, and the oxygen activity a is0556 ppm; the slag thickness d of the steel slag is 0.05m, the slag discharging thickness is 0.01m, and the thickness of the added slag is 0.04 m; the adopted process is primary smelting furnace smeltingVacuum refining and continuous casting in a VD furnace.
Specifically, the method for preparing a low-sulfur low-nitrogen low-hydrogen steel material at low cost in this embodiment includes:
(1) primary smelting in a converter: baking the steel ladle by adopting normal turnover online, wherein the temperature of molten steel before tapping is 1705 ℃; the temperature of the molten steel after tapping is 1640 ℃; after tapping, the S% in the molten steel is 69ppm, and the slag thickness of the steel slag is 0.05 m; the temperature of the inner wall of the ladle before tapping is 1080 ℃; deoxidizing and alloying the molten steel and the steel slag in the process of tapping the molten steel; deoxygenation, comprising: adding aluminum into molten steel and steel slag, wherein the addition amount of the aluminum is 682 Kg; after the alloying is finished, slag charge is added for modifying the slag, wherein the addition amount of lime is 6.0Kg/t steel, the addition amount of light-burned dolomite is 2.0Kg/t steel, and the addition amount of fluorite is 1.0Kg/t steel.
(2) Vacuum refining in a VD furnace: the temperature of molten steel when VD enters the station is 1630 ℃; the temperature of the molten steel after the VD furnace vacuum refining is finished is 1570 ℃; the pressure of the vacuum chamber is less than or equal to 67Pa, and the vacuum treatment time is 11 min; when VD enters the station, the mass percent of aluminum in the molten steel is 0.079%; stirring the slag steel by adopting the large-bottom argon blowing amount with the flow rate of 2.00NL/(min t steel); after the vacuum refining of the VD furnace is finished, the steel slag comprises the following components in percentage by mass: CaO 58.13%, Al2O3 30.29％、MgO 6.13％、SiO23.87 percent and 0.61 percent of (FeO + MnO); the total slag amount of the steel slag is 9.5Kg/t steel. After completion of the vacuum refining in the VD furnace, the S% in the molten steel was 22ppm, the hydrogen content was 1.12ppm, and the nitrogen content was 26 ppm.
(3) Continuous casting: the temperature of the tundish is 1537 ℃, and the continuous casting is carried out to obtain a casting blank with the section of 300mm multiplied by 2000 mm.
Example 3:
in the embodiment, the steel grade Q345Z-25 is selected, the tapping quantity is 152t, the liquidus temperature is 1517 ℃, and the oxygen activity a is0541 ppm; the slag thickness d of the steel slag is 0.04m, the slag discharging thickness is 0.01m, and the thickness of the added slag is 0.03 m; the adopted processes are electric furnace primary smelting, VD furnace vacuum refining and continuous casting.
Specifically, the method for preparing a low-sulfur low-nitrogen low-hydrogen steel material at low cost in this embodiment includes:
(1) primary smelting in a converter: baking the steel ladle on line by adopting normal turnover, wherein the temperature of molten steel before tapping is 1706 ℃; the temperature of the molten steel after tapping is 1654 ℃; after tapping, the S% in the molten steel is 38ppm, and the slag thickness of the steel slag is 0.04 m; the temperature of the inner wall of the ladle before tapping is 1180 ℃; deoxidizing and alloying the molten steel and the steel slag in the process of tapping the molten steel; deoxygenation, comprising: adding aluminum into molten steel and steel slag, wherein the addition amount of the aluminum is 474 Kg; after the alloying is finished, slag charge is added for modifying the slag, wherein the addition amount of lime is 5.3Kg/t steel, the addition amount of light-burned dolomite is 1.2Kg/t steel, and the addition amount of fluorite is 0.5Kg/t steel.
(2) Vacuum refining in a VD furnace: the temperature of molten steel when VD enters the station is 1642 ℃; the temperature of the molten steel after the VD furnace vacuum refining is finished is 1575 ℃; the pressure of the vacuum chamber is less than or equal to 67Pa, and the vacuum treatment time is 15 min; when VD enters the station, the mass percent of aluminum in the molten steel is 0.10 percent; stirring the slag steel by adopting the large-bottom argon blowing amount with the flow rate of 3.00NL/(min t steel); after the vacuum refining of the VD furnace is finished, the steel slag comprises the following components in percentage by mass: CaO 59.13%, Al2O3 29.30％、MgO 6.36％、SiO24.12% and (FeO + MnO) 0.53%; the total slag amount of the steel slag is 7.7Kg/t steel. After the completion of vacuum refining in the VD furnace, the S% in the molten steel was 16ppm, the hydrogen content was 1.08ppm, and the nitrogen content was 24 ppm.
(3) Continuous casting: the temperature of the tundish is 1540 ℃, and the continuous casting is carried out to obtain a casting blank with the section of 300mm multiplied by 2000 mm.
Comparative example 1:
in the embodiment, the steel grade Q345D is selected, the tapping quantity is 153t, the liquidus temperature is 1518 ℃, and the oxygen activity a0 is 642 ppm; the slag thickness d of the steel slag is 0.08m, the slag discharging thickness is 0.06m, and the thickness of the added slag is 0.02 m; the adopted processes are converter smelting, VD furnace vacuum refining and continuous casting.
Specifically, the method for preparing a low-sulfur low-nitrogen low-hydrogen steel material at low cost in this embodiment includes:
(1) primary smelting in a converter: the steel ladle is baked on line by adopting normal turnover, and the temperature of molten steel before tapping is 1680 ℃; the temperature of the molten steel after tapping is 1620 ℃; the temperature of the inner wall of the ladle before tapping is 1020 ℃; deoxidizing and alloying the molten steel and modifying slag in the process of tapping the molten steel; deoxygenation, comprising: adding 298Kg of aluminum into molten steel and steel slag; after the alloying is finished, slag charge is added for modifying the slag, wherein the addition amount of lime is 3.3Kg/t steel, the addition amount of light-burned dolomite is 0.9Kg/t steel, and the addition amount of fluorite is 0.5Kg/t steel.
(2) Vacuum refining in a VD furnace: the temperature of molten steel when VD enters the station is 1605 ℃; the temperature of the molten steel after the vacuum refining of the VD furnace is 1550 ℃; the pressure of the vacuum chamber is less than or equal to 67Pa, and the vacuum treatment time is 15 min; when VD enters the station, the mass percent of aluminum in the molten steel is 0.05 percent; stirring the slag steel by adopting the large-bottom argon blowing amount with the flow rate of 3.00NL/(min t steel); after the vacuum refining of the VD furnace is finished, the steel slag comprises the following components in percentage by mass: 49.13% CaO and Al2O3 31.30％、MgO 7.06％、SiO25.12% and (FeO + MnO) 1.53%; the total slag amount of the steel slag is 5.7Kg/t steel. After the completion of the vacuum refining in the VD furnace, the S% in the molten steel was 40ppm, the hydrogen content was 1.6ppm, and the nitrogen content was 38 ppm.
(3) Continuous casting: the temperature of the tundish is 1525 ℃, and the continuous casting is carried out to obtain a casting blank with the section of 300mm multiplied by 2000 mm.
From the above comparison of the above-described examples 1 to 3 of the present invention with comparative example 1, it can be seen that: according to the method for preparing the low-sulfur low-nitrogen low-hydrogen steel at low cost, the sulfur content and the hydrogen and nitrogen content in the molten steel can be efficiently reduced to be below target values by controlling the temperature of the molten steel before tapping, the temperature of the molten steel after tapping, the slag amount during tapping, deoxidation alloying and slag modification during tapping, the temperature of the molten steel when VD is in station, VD deep vacuum treatment time, the temperature of the molten steel after VD furnace vacuum refining and the temperature of the molten steel in a continuous casting tundish, and meanwhile, the process cost is greatly reduced, the refining time is reduced, the production rhythm is accelerated, and the refining efficiency is improved. In the comparative example 1, the temperature of all the subsequent molten steel is low due to the low temperature of the inner wall of the steel ladle, and the final continuous casting temperature is too low, so that the casting is easily interrupted; meanwhile, in the comparative example 1, the added aluminum amount and the slag charge amount of the steel are too low, and the mass percentage content of VD aluminum entering the station is too low, so that the final oxidizability of the furnace is too high, and the sulfur content cannot be reduced to below 20 ppm.
Finally, it should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (10)
1. A method for preparing low-sulfur low-nitrogen low-hydrogen steel at low cost comprises the following steps: smelting in a primary smelting furnace, vacuum refining in a VD furnace and continuous casting; the method is characterized in that:
in the smelting process of the primary smelting furnace, the temperature of molten steel before tapping is (T)L+180 ℃) +/-10 ℃; the temperature of the molten steel after tapping is (T)L+130 ℃) +/-10 ℃; after tapping, the S% in molten steel is less than or equal to 80ppm, and the slag thickness of the steel slag is less than 0.07 m;
in the vacuum refining process of the VD furnace, the molten steel temperature when VD enters the station is (T)L+120 ℃) +/-10 ℃; the molten steel temperature after the VD furnace vacuum refining is finished is (T)L+60℃)±10℃；
In the continuous casting process, the temperature of the molten steel in the continuous casting tundish is (T)L+20℃)±5℃；
Wherein, T isLIs the liquidus temperature.
2. The method for producing a low-sulfur, low-nitrogen and low-hydrogen steel material at low cost according to claim 1, wherein the temperature of the inner wall of the ladle before tapping is 1050 to 1200 ℃ during the primary smelting.
3. The method for producing a low-sulfur, low-nitrogen and low-hydrogen steel product at low cost according to claim 1 or 2, wherein molten steel and steel slag are deoxidized and alloyed during tapping of molten steel during the primary smelting;
the deoxidation comprises the following steps: adding aluminum into molten steel and steel slag, wherein the addition amount of the aluminum is (1.45m +0.25 a)0+1.63d-80)Kg～(1.45m+0.25a0+1.63d +50) Kg; wherein m is the weight of the molten steel; a is0The oxygen activity of the molten steel before tapping of the molten steel is obtained; d is the thickness of the steel slag.
4. The method for producing a low-sulfur, low-nitrogen and low-hydrogen steel product at low cost according to claim 1 or 2, wherein, during the primary smelting, after the alloying is completed, slag is added to the molten steel and the steel slag to modify the slag;
wherein the slag comprises: lime, light burned dolomite, and fluorite;
the additive amount of the lime is 4.0-6.0 Kg/t steel, the additive amount of the light-burned dolomite is 1.0-2.0 Kg/t steel, and the additive amount of the fluorite is 0.5-1.0 Kg/t steel.
5. The method for producing a low-sulfur, low-nitrogen and low-hydrogen steel material at low cost according to claim 1 or 2, wherein the vacuum treatment time for which the vacuum chamber pressure is less than or equal to 67Pa in the vacuum refining process in the VD furnace is 8-15 min.
6. The method for producing a low-sulfur, low-nitrogen and low-hydrogen steel material at low cost according to claim 1 or 2, wherein during the vacuum refining in the VD furnace, the slag steel is stirred by blowing argon gas at a flow rate of 1.50 to 3.00 NL/(min-t steel) at a large bottom.
7. The method for producing a low-sulfur, low-nitrogen and low-hydrogen steel product at low cost according to claim 1 or 2, wherein in the vacuum refining process of the VD furnace, the mass percentage of aluminum in molten steel when VD is at a station is 0.06-0.10%.
8. The method for producing a low-sulfur, low-nitrogen and low-hydrogen steel product as claimed in claim 1 or 2, wherein the sulfur content in the molten steel is 0.008% or less by mass after completion of the initial smelting in the initial smelting furnace.
9. The method for preparing low-sulfur low-nitrogen low-hydrogen steel material at low cost according to claim 1 or 2, wherein the steel slag comprises the following components in percentage by mass after the completion of vacuum refining in the VD furnace: 55-65% of CaO and Al2O3 30～35％、MgO 6～11％、SiO2 3～6％、(FeO+MnO)<0.8％；
The total slag amount of the steel slag is 7-10 Kg/t steel.
10. A steel sheet produced by the method for producing a low-sulfur, low-nitrogen, and low-hydrogen steel product at low cost according to any one of claims 1 to 9.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115491465A (en) * | 2022-09-23 | 2022-12-20 | 舞阳钢铁有限责任公司 | Method for producing low-alloy series steel grade by electric furnace-VD process |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001342512A (en) * | 2000-06-05 | 2001-12-14 | Sanyo Special Steel Co Ltd | Highly clean steel and production method |
| JP2015178646A (en) * | 2014-03-19 | 2015-10-08 | Ｊｆｅスチール株式会社 | Method of forming ingot of low-sulfur steel |
| CN108118115A (en) * | 2016-11-28 | 2018-06-05 | 宝山钢铁股份有限公司 | A kind of method of VD flows smelting high carbon chromium bearing steel |
| CN111321274A (en) * | 2020-04-16 | 2020-06-23 | 首钢京唐钢铁联合有限责任公司 | Method for controlling aluminum in molten steel in refining process |
| CN111334642A (en) * | 2020-03-12 | 2020-06-26 | 江阴兴澄特种钢铁有限公司 | Smelting and pouring method of sulfur-containing and nitrogen-containing molten steel |
-
2021
- 2021-06-18 CN CN202110680604.5A patent/CN113430448B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001342512A (en) * | 2000-06-05 | 2001-12-14 | Sanyo Special Steel Co Ltd | Highly clean steel and production method |
| JP2015178646A (en) * | 2014-03-19 | 2015-10-08 | Ｊｆｅスチール株式会社 | Method of forming ingot of low-sulfur steel |
| CN108118115A (en) * | 2016-11-28 | 2018-06-05 | 宝山钢铁股份有限公司 | A kind of method of VD flows smelting high carbon chromium bearing steel |
| CN111334642A (en) * | 2020-03-12 | 2020-06-26 | 江阴兴澄特种钢铁有限公司 | Smelting and pouring method of sulfur-containing and nitrogen-containing molten steel |
| CN111321274A (en) * | 2020-04-16 | 2020-06-23 | 首钢京唐钢铁联合有限责任公司 | Method for controlling aluminum in molten steel in refining process |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115491465A (en) * | 2022-09-23 | 2022-12-20 | 舞阳钢铁有限责任公司 | Method for producing low-alloy series steel grade by electric furnace-VD process |
| CN115491465B (en) * | 2022-09-23 | 2024-03-12 | 舞阳钢铁有限责任公司 | Method for producing low alloy series steel grade by electric furnace-VD process |
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