CN113604631B - Method for inhibiting refining and resulfurization of low-sulfur steel in LF (ladle furnace) - Google Patents
Method for inhibiting refining and resulfurization of low-sulfur steel in LF (ladle furnace) Download PDFInfo
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- CN113604631B CN113604631B CN202110804125.XA CN202110804125A CN113604631B CN 113604631 B CN113604631 B CN 113604631B CN 202110804125 A CN202110804125 A CN 202110804125A CN 113604631 B CN113604631 B CN 113604631B
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/064—Dephosphorising; Desulfurising
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/0037—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00 by injecting powdered material
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/0087—Treatment of slags covering the steel bath, e.g. for separating slag from the molten metal
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C2007/0093—Duplex process; Two stage processes
Abstract
A method for inhibiting refining and resulfurization of low-sulfur steel in an LF (ladle furnace) comprises the following steps: desulfurizing molten iron of steel grade requiring that S content is not more than 0.03 wt%; smelting in a converter; refining in an LF furnace; pouring and subsequent processes, wherein the time from the end of molten steel pouring to the beginning of pouring the refining slag in the molten steel tank is controlled not to exceed 13 min; and then, filling the smelted low-sulfur molten steel into the molten steel tank, and conventionally refining the molten steel in an LF furnace and performing the subsequent processes. The invention firstly smelts a steel grade with the S content not more than 0.03wt% in one furnace, and controls the alkalinity of the refining slag in the LF furnace to be not more than 1.2 and the sulfur content in the refining slag to be not more than 0.2wt%, thereby reducing the sulfur content attached to the molten steel tank; after the low-sulfur molten steel to be refined is filled into the molten steel tank, the resulfurization of the low-sulfur steel after LF refining is stabilized to be not more than 0.001wt%, the rate of change of the low-sulfur steel is reduced to 1.25% from the original 15.78%, and the consumption of steel materials (molten iron slagging) is reduced by 2-3 kg/t.
Description
Technical Field
The invention relates to a smelting method of low-sulfur steel, and particularly belongs to a method for inhibiting refining and resulfurization of low-sulfur steel in an LF (ladle furnace). The invention is suitable for refining low-sulfur steel without desulfurization capability in the LF furnace.
Background
The molten steel tank is used for receiving molten steel and carrying out pouring operation in the steelmaking process. The molten steel tank is a large tool in the steel making process, and is unlikely to be replaced at any time, and components between an upper furnace and a lower furnace can generate interference in the process of changing the variety steel, such as: after the molten steel in the previous furnace is subjected to deep desulfurization, when steel types (cord steel, spring steel and industrial pure iron) which do not have desulfurization conditions in the LF furnace process are smelted, the molten steel tank can generate an obvious resulfurization phenomenon, the sulfur content is increased by 0.0015-0.005 wt%, and the molten steel components are possibly unqualified.
The 'resulfurization' reason in the ladle of the LF furnace is as follows: in refining, the pouring process, the slag can be attached to the jar wall, and when the operation of overturning the jar was carried out to the molten steel after pouring up, the molten steel can be poured completely because of the mobility, and partial slag can remain in the molten steel jar, and the sulfur content of molten steel can be influenced to the physicochemical characteristic of residue, weight in the jar: the sulfur content in the last furnace slag is high, when the steel grade is smelted by low-alkalinity slag or high-oxidizability slag, the sulfur capacity of the furnace slag is low, and the residual high-sulfur slag and low-sulfur molten steel generate sulfur diffusion and transfer, so that the sulfur content in the molten steel is increased, and resulfurization is formed. The higher the desulfurization efficiency of the last furnace is, the higher the sulfur content of the slag is, and the more serious the resulfurization phenomenon is.
At present, in order to relieve the influence of residues in a molten steel tank on 'resulfurization', three methods are generally adopted: firstly, the next pot of molten steel is continuously desulfurized in an LF furnace to produce high-alkalinity reducing slag, so that the desulfurization amount is far larger than the sulfur return amount, and the method is not suitable for all steel types, such as cord steel for producing acid slag and ultra-low carbon steel for producing high-oxidizability slag; secondly, the low-sulfur molten steel is produced by the converter, the molten steel tank is flushed, the content of residual sulfur in the tank is reduced, and a furnace dismantling machine is used for cleaning large slag blocks in the molten steel tank, so that not only is the cost of deep desulfurization of the molten iron increased, but also the fluctuation of the resulfurization of the next furnace is large as long as the low-sulfur molten steel is subjected to desulfurization reaction; and thirdly, the sulfur content of the molten steel tapped from the converter is further reduced, so that the resulfurization value is controlled within an acceptable range, and the overall cost of molten iron desulphurization is increased.
The related articles and patents are searched, and in a patent 'a method for preventing resulfurization in a molten steel tank after tapping', publication No. CN108950142A, 2-5 kg/t of steel lime and 0.5-1.5 kg/t of refined fluxing slag are added after the converter taps, the slag turning time is less than 15min after the molten steel tank is cast, and the molten steel tank containing the molten steel at the last time is used in a grading way: the normal tank does not need special control; the high sulfur pot is only used for the next time of the killed steel tapping pot (i.e. aluminum deoxidation, desulfurization). The method is characterized in that the reducing slag is desulfurized by adding aluminum (0.026 wt%), the desulfurization amount is approximately equal to the sulfur increase amount, the effect of no resulfurization is achieved, but the requirement on steel types is limited, and the method cannot be used for steel types which do not allow aluminum to be added or can not produce high-alkalinity reducing slag. The other articles adopt ways of improving the desulfurization efficiency of the LF furnace, rinsing the RH vacuum chamber and the like to reduce the influence of resulfurization, and do not analyze and solve the resulfurization of residues in the molten steel tank.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a method for preventing low-sulfur steel from being refined and resulfurized in an LF furnace, wherein the steel grade requiring the S content not more than 0.03wt% in the first furnace is smelted, the alkalinity of refining slag in the LF furnace is controlled to be not more than 1.2, and the sulfur content in the refining slag is controlled to be not more than 0.03wt%, so that the sulfur content attached to residues in a molten steel tank is reduced, and the resulfurization value of the low-sulfur steel refined and resulfurized in the LF furnace is stabilized to be not more than 0.001wt% after the low-sulfur molten steel to be refined is filled in the molten steel tank.
The measures for realizing the aim are as follows:
a method for inhibiting refining and resulfurization of low-sulfur steel in an LF (ladle furnace) is characterized by comprising the following steps: the method comprises the following steps:
1) the molten iron of steel grade with the S content not more than 0.03wt% is desulfurized, and the sulfur content in the desulfurized molten iron is controlled to be less than or equal to 0.02 wt%;
2) performing converter smelting, and controlling the sulfur content of molten steel at the smelting end point to be less than or equal to 0.025 wt%;
3) refining in an LF furnace:
adding lime according to 5-7 Kg/ton of steel, adding quartz sand according to 3-5 Kg/ton of steel after 5-20 min intervals, and continuously refining for not less than 5 min; then adding a covering agent according to 0.7-2 Kg per ton of steel; controlling the alkalinity of the refining slag to be less than or equal to 1.2 and the sulfur content in the refining slag to be less than or equal to 0.2 wt%;
4) pouring and subsequent processes are carried out, and the time from the end of molten steel pouring to the beginning of pouring the refining slag in the molten steel tank is controlled not to exceed 13 min;
5) and then, filling the smelted low-sulfur molten steel into the ladle furnace, and carrying out conventional refining and post-processing on the low-sulfur molten steel in an LF furnace.
Further: lime is added at 5.6-6.6 Kg per ton of steel.
Further, the method comprises the following steps: adding quartz sand into the steel at a ratio of 3.5-4.6 Kg/ton.
Further: the alkalinity of the refining slag is controlled to be less than or equal to 1.0.
Further: and controlling the time from the end of molten steel pouring to the beginning of pouring the refining slag in the molten steel tank to be less than 10 min.
Action and mechanism of the main process in the invention
The invention controls the sulfur content of the molten steel to be less than or equal to 0.025wt% at the smelting end point of the converter for the steel grade with the S content of less than or equal to 0.03wt%, because the sulfur content in the molten steel is increased after the sulfur content in the molten steel exceeds 0.025wt%, the use effect of the method can be influenced by the increase of the sulfur content in a small amount of cold steel and residues in the molten steel tank;
in the invention, during the refining of steel with the S content not more than 0.03wt% in an LF furnace, lime is added according to 5-7 Kg/ton steel, quartz sand is added according to 3-5 Kg/ton steel after 5-20 min, and then the refining is continued for not less than 5 min; then adding a covering agent according to 0.7-2 Kg per ton of steel; the alkalinity of the refining slag is controlled to be less than or equal to 1.2, and the sulfur content in the refining slag is controlled not to exceed 0.2wt%, because: by adding relatively fixed lime (CaO) amount and quartz Sand (SiO)2) Amount, regulating slag to low alkalinity slag (alkalinity formula)
The low alkalinity makes the slag not have the thermodynamic condition of desulfurization, the sulfur content of the slag is low, thus the sulfur of the molten steel tank is gathered in the molten steel, and the slag does not remain in the molten steel tank after the continuous casting is finished, and the low alkalinity slag has the characteristic of good fluidity, is difficult to crust, is easy to turn clean when the tank is turned over, and reduces the weight of the residue in the tank. The aim of relieving the influence of the residues in the molten steel tank on resulfurization is achieved. The refining time after the low-alkalinity slag is manufactured is more than or equal to 5min, the alkalinity is less than or equal to 1.2, and the sulfur content in the refining slag is not more than 0.2wt percent, so that the sulfur is better promoted to be transferred to the molten steel tank.
The invention does not exceed 13min from the end of molten steel pouring to the beginning of pouring the refining slag in the molten steel tank in the pouring and subsequent process stages because the temperature in the tank is reduced along with the increase of time, the slag is cooled and solidified and can not be completely discharged, so that the resulfurization phenomenon of the next furnace can be caused, the sulfur content is increased, and the invention is very unfavorable for refining low-sulfur steel.
Compared with the prior art, the method has the advantages that the steel grade with the S content not more than 0.03wt% is smelted in the first furnace, the alkalinity of the refining slag in the LF furnace is controlled to be not more than 1.2, the sulfur content in the refining slag is controlled to be not more than 0.2wt%, so that the sulfur content attached to the molten steel tank is reduced, the resulfurization of the low-sulfur steel refined by the LF furnace is stabilized to be not more than 0.001wt%, the rate of change of the low-sulfur steel is reduced to 1.25% from the original 15.78%, the target of tapping sulfur of the converter is improved by 0.0015 wt%, and the consumption of steel materials (slagging-off of molten iron) is reduced by 2-3 kg/t.
Detailed Description
The present invention is described in detail below:
example 1
The prior art is as follows:
the smelting steel is 82B, silicon deoxidized steel, the sulfur content in the tapped molten steel is 0.021 wt%, and the alkalinity of refining slag in an LF furnace is 2.68; the time from the end of molten steel pouring to the turning of a molten steel tank is 13 min; after hot repair, the steel cord is put into cord steel LX72A for production, and detection shows that: the sulfur in the tapping molten steel is 0.0083 wt%; after acid slag is produced in the LF furnace, the resulfurization is carried out to 0.0114 wt%, and the resulfurization is 0.0031 wt%.
The invention comprises the following steps:
1) the HPB300 steel grade with the required S content not exceeding 0.03wt percent; performing molten iron desulphurization, and controlling the sulfur content in the desulfurized molten iron to be 0.018 wt%;
2) performing converter smelting, wherein the sulfur content of molten steel at the smelting end point is 0.023 wt%;
3) refining in an LF furnace:
adding lime according to 5.4 Kg/ton steel, adding quartz sand according to 3.5 Kg/ton steel after 6min interval, and refining for 8 min; adding 0.82 Kg/ton steel covering agent; through detection, the alkalinity of the refining slag is 1.12, and the sulfur content in the refining slag is 0.089 wt%;
4) pouring and subsequent processes are carried out, and the time from the end of molten steel pouring to the beginning of pouring the refining slag in the molten steel tank is controlled to be 13 min;
5) then, the smelted molten steel of the low-sulfur steel (cord steel LX72A) is filled into the molten steel tank, and the molten steel of low sulfur is subjected to conventional refining and post-processing in an LF furnace.
By detecting the produced low-sulfur steel cord steel LX72A, the sulfur content in the molten steel of the steel is 0.0081 wt%, the sulfur is recovered to 0.009 wt% after acid slag is produced in an LF furnace, the sulfur increase is 0.0009 wt%, and the requirement of the steel cord steel LX72A is completely met.
Example 2
The prior art is as follows:
the steel grade is GM10Mn, the sulfur content in the tapped molten steel is 0.018 wt%, the alkalinity of the refining slag in the LF furnace is 0.89, the sulfur content in the refining slag is 0.043 wt%, and the time from the end of molten steel pouring to the time of a ladle-turning tank is 25 min; after hot repair, putting the ultra-low carbon steel DL05 into production, and detecting: the sulfur in the tapping molten steel is 0.0042 wt%; after heating and refining in an LF furnace, the resulfurization is carried out to 0.077 wt%, and the resulfurization is 0.0035 wt%.
The invention comprises the following steps:
1) steel grade GM10Mn, which requires an S content of no more than 0.025 wt%; carrying out molten iron desulphurization, and controlling the sulfur content in the desulfurized molten iron to be 0.014 wt%;
2) performing converter smelting, wherein the sulfur content of molten steel at the smelting end point is 0.019 wt%;
3) refining in an LF furnace:
adding lime at a rate of 6.7 Kg/ton steel, adding quartz sand at an interval of 6min at a rate of 4.9 Kg/ton steel, and refining for 10 min; adding 0.85Kg per ton of steel covering agent; through detection, the alkalinity of the refining slag is 0.93, and the sulfur content in the refining slag is 0.046 wt%;
4) pouring and subsequent processes are carried out, and the time from the end of pouring the molten steel to the beginning of pouring the refining slag in the molten steel tank is controlled to be 11 min;
5) and then, the smelted low-sulfur steel (ultra-low carbon steel DL05) molten steel is filled into the molten steel tank, and the low-sulfur molten steel is subjected to conventional refining and post-processing in an LF furnace.
By detecting the produced low-sulfur steel ultra-low-carbon steel DL05, the sulfur content in the molten steel is 0.0041 wt%, the sulfur is increased back to 0.0048 wt% after heating and refining in an LF furnace, and the sulfur increase is 0.0007 wt%, so that the requirement of ultra-low-carbon steel DL05 is met.
Example 3
The prior art is as follows:
the steel grade in the steel making is Q235: the sulfur content in the desulfurized molten iron is 0.035 wt%, the sulfur content in the tapped molten steel is 0.039 wt%, the alkalinity of the refining slag in the LF furnace is 0.96, and the time from the end of molten steel pouring to the time of a ladle tilting tank is 9 min; after hot repair, the steel cord is put into cord steel LX72A for production, and after detection: the sulfur in the tapping molten steel is 0.0087 wt%; after acid slag is produced in an LF furnace, the sulfur is returned to 0.0124 wt%, and the sulfur increase is 0.0043 wt%.
The invention comprises the following steps:
1) the steel grade HPB300 requiring S content not exceeding 0.030 wt%; after the molten iron desulphurization, the sulfur content in the molten iron after the desulphurization is controlled to be 0.019 wt%;
2) performing converter smelting, wherein the sulfur content of molten steel at the smelting end point is 0.022 wt%;
3) refining in an LF furnace:
adding lime according to 5.2 Kg/ton steel, adding quartz sand according to 3.3 Kg/ton steel after 6min interval, and refining for 7 min; adding 0.72 Kg/ton steel covering agent; through detection, the alkalinity of the refining slag is 1.04, and the sulfur content in the refining slag is 0.077 wt%;
4) pouring and subsequent processes are carried out, and the time from the end of molten steel pouring to the beginning of pouring the refining slag in the molten steel tank is controlled to be 8 min;
5) then, the smelted molten steel of the low-sulfur steel (cord steel LX72A) is filled into the molten steel tank, and the molten steel of low sulfur is subjected to conventional refining and post-processing in an LF furnace.
By detecting the produced low-sulfur steel cord steel LX72A, the sulfur content in the molten steel is 0.0054 wt%, after acid slag is produced in an LF furnace, the sulfur is recovered to 0.0060 wt%, the sulfur increase is 0.0006 wt%, and the requirement of the cord steel LX72A is met.
Example 4
The prior art is as follows:
the steel grade is HPB300, the sulfur content in the tapped molten steel is 0.018 wt%, the alkalinity of the refining slag in the LF furnace is 1.18, and the sulfur content in the refining slag is 0.43 wt%; the time from the end of molten steel pouring to the time of a ladle tilting is 9 min; after hot repair, the steel cord is put into cord steel LX72A for production, and detection shows that: the sulfur in the tapping molten steel is 0.0072 wt%; after acid slag is produced in an LF furnace, the sulfur is returned to 0.0121 wt%, and the sulfur increase is 0.0049 wt%.
The invention comprises the following steps:
1) steel grade GM10Mn, which requires an S content of no more than 0.025 wt%; the sulfur content in the desulfurized molten iron is 0.008 wt%;
2) performing converter smelting, wherein the sulfur content of molten steel at the smelting end point is 0.012 wt%;
3) refining in an LF furnace:
adding lime according to 5.9 Kg/ton steel, adding quartz sand according to 4.5 Kg/ton steel after 10min interval, and refining for 15 min; adding 0.86Kg per ton of steel covering agent; through detection, the alkalinity of the refining slag is 0.68, and the sulfur content in the refining slag is 0.057 wt%;
4) pouring and subsequent processes are carried out, and the time from the end of molten steel pouring to the beginning of pouring the refining slag in the molten steel tank is controlled to be 7 min;
5) then, the smelted molten steel of the low-sulfur steel (cord steel LX72A) is filled into the molten steel tank, and the molten steel of low sulfur is subjected to conventional refining and post-processing in an LF furnace.
By detecting the produced low-sulfur steel cord steel LX72A, the sulfur content in the molten steel of the steel is 0.0054 wt%, the sulfur is recovered to 0.0056 wt% after acid slag is produced in an LF furnace, the sulfur increase is 0.0002 wt%, and the requirement of the steel cord steel LX72A is met.
Example 5
The prior art is as follows:
the steel grade is HPB300, the sulfur content in the tapped molten steel is 0.018 wt%, refining is continued for 2min after quartz sand is added into an LF furnace, and the alkalinity of refining slag is 1.13; the time from the end of molten steel pouring to the time of a ladle tilting is 9 min; after hot repair, the steel cord is put into cord steel LX72A for production, and detection shows that: the sulfur in the tapping molten steel is 0.0053 wt%; after acid slag is produced in an LF furnace, the resulfurization is carried out to 0.0089 wt%, and the resulfurization is 0.0036 wt%.
The invention comprises the following steps:
1) steel grade GM10Mn, which requires an S content of no more than 0.025 wt%; the sulfur content in the desulfurized molten iron is 0.015 wt%;
2) performing converter smelting, wherein the sulfur content of molten steel at the smelting end point is 0.018 wt%;
3) refining in an LF furnace:
adding lime according to 5.3 Kg/ton steel, adding quartz sand according to 4.8 Kg/ton steel after 10min interval, and refining for 15 min; adding 0.89 Kg/ton steel covering agent; the detection shows that the alkalinity of the refining slag is 0.76 and the sulfur content in the refining slag is 0.068 wt%;
4) pouring and subsequent processes are carried out, and the time from the end of molten steel pouring to the beginning of pouring the refining slag in the molten steel tank is controlled to be 10 min;
5) then, the smelted molten steel of the low-sulfur steel (cord steel LX72A) is filled into the molten steel tank, and the molten steel of low sulfur is subjected to conventional refining and post-processing in an LF furnace.
By detecting the produced low-sulfur steel cord steel LX72A, the sulfur content in the molten steel is 0.0064 wt%, the sulfur is recovered to 0.0071 wt% after acid slag is produced in an LF furnace, the sulfur increase is 0.0007 wt%, and the requirement of the steel cord steel LX72A is met.
Example 6
The condition of smelting low-sulfur steel in the prior art is as follows:
the steel grade is HPB300, the sulfur content in the tapped molten steel is 0.013 wt%, the alkalinity of the LF refining slag is 1.18, and 0.28Kg of covering agent is added per ton of steel; the time from the end of molten steel pouring to the use of a ladle tilting tank is 11 min; after hot repair, putting the ultra-low carbon steel DL05 into production, and detecting: the sulfur in the tapping molten steel is 0.0045 wt%; after heating and refining in an LF furnace, the sulfur is returned to 0.0066 wt%, and the sulfur is increased to 0.0021 wt%.
The invention comprises the following steps:
1) the steel grade HPB300 requiring S content not exceeding 0.030 wt%; the sulfur content in the desulfurized molten iron is 0.011 wt%;
2) performing converter smelting, wherein the sulfur content of molten steel at the smelting end point is 0.015 wt%;
3) refining in an LF furnace:
adding lime according to 5.2 Kg/ton steel, adding quartz sand according to 3.1 Kg/ton steel after 8min interval, and refining for 15 min; adding 1.5 Kg/ton steel covering agent; the detection shows that the alkalinity of the refining slag is 0.96 and the sulfur content in the refining slag is 0.115 wt%;
4) pouring and subsequent processes are carried out, and the time from the end of pouring the molten steel to the beginning of pouring the refining slag in the molten steel tank is controlled to be 6.5 min;
5) and then, the smelted low-sulfur steel (ultra-low carbon steel DL05) molten steel is loaded into the molten steel tank, and the low-sulfur molten steel is subjected to conventional refining and post-processing in an LF furnace.
By detecting the produced low-sulfur steel DL05, the sulfur content in the molten steel is 0.0038 wt%, the sulfur is raised back to 0.0042 wt% after acid slag is produced in an LF furnace, the sulfur increase is 0.0004 wt%, and the requirement of ultra-low-carbon steel DL05 is met.
Claims (5)
1. A method for inhibiting refining and resulfurization of low-sulfur steel in an LF (ladle furnace) is characterized by comprising the following steps: the method comprises the following steps:
1) the molten iron of steel grade with the S content not more than 0.03wt% is desulfurized, and the sulfur content in the desulfurized molten iron is controlled to be less than or equal to 0.02 wt%;
2) performing converter smelting, and controlling the sulfur content of molten steel at the smelting end point to be less than or equal to 0.025 wt%;
3) refining in an LF furnace:
adding lime according to 5-7 Kg/ton of steel, adding quartz sand according to 3-5 Kg/ton of steel after 5-20 min intervals, and continuously refining for not less than 5 min; then adding a covering agent according to 0.7-2 Kg per ton of steel; controlling the alkalinity of the refining slag to be less than or equal to 1.2 and the sulfur content in the refining slag to be less than or equal to 0.2 wt%;
pouring and subsequent processes are carried out, and the time from the end of molten steel pouring to the beginning of pouring the refining slag in the molten steel tank is controlled not to exceed 13 min;
and then, filling the smelted low-sulfur molten steel into the molten steel tank, and carrying out conventional refining and post-working procedures on the low-sulfur molten steel in an LF (ladle furnace).
2. The method for inhibiting the refining and resulfurization of low-sulfur steel in an LF furnace according to claim 1, wherein the method comprises the following steps: lime is added according to 5.6-6.6 Kg per ton of steel.
3. The method for inhibiting the refining and resulfurization of low-sulfur steel in an LF furnace according to claim 1, wherein the method comprises the following steps: the quartz sand is added according to 3.5-4.6 Kg per ton of steel.
4. The method for inhibiting the refining and resulfurization of low-sulfur steel in an LF furnace according to claim 1, wherein the method comprises the following steps: controlling the alkalinity of the refining slag not to exceed 1.0.
5. The method for inhibiting the refining and resulfurization of low-sulfur steel in an LF furnace according to claim 1, wherein the method comprises the following steps: and controlling the time from the end of molten steel pouring to the beginning of pouring the refining slag in the molten steel tank to be less than 10 min.
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| CN103642969B (en) * | 2013-12-03 | 2015-10-14 | 攀钢集团攀枝花钢铁研究院有限公司 | A kind of hot metal containing V-Ti smelts the method that electrical steel process returns sulphur control |
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