CN111876555A - Smelting method for stably controlling sulfur content of non-quenched and tempered steel - Google Patents
Smelting method for stably controlling sulfur content of non-quenched and tempered steel Download PDFInfo
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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
- C21C7/06—Deoxidising, e.g. killing
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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
- C21C5/30—Regulating or controlling the blowing
- C21C5/35—Blowing from above and through the bath
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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
- 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
- C21C7/072—Treatment with gases
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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
- C21C7/076—Use of slags or fluxes as treating agents
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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
- C21C7/10—Handling in a vacuum
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
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Abstract
The invention discloses a smelting method for stably controlling the sulfur content of non-quenched and tempered steel, which comprises the following steps: (1) smelting in a converter; (2) treating the furnace and an argon station; (3) LF refining; (4) RH degassing treatment; (5) continuous casting; the method strictly controls the sulfur content of the charging scrap steel during charging, and performs strong dephosphorization in the early stage of smelting, high-speed carbon-drawing operation, and post-furnace and deoxidation operation; strictly controlling the adding proportion of manufactured slag materials, the component content of refining slag and the alkalinity of slag in an LF refining stage; then, fine adjustment is carried out on the slag according to the change trend of the sulfur content in the process, the sulfur content at the outlet is controlled according to the upper limit of the protocol standard, the degassing process ensures that the slag surface is not greatly stirred, the casting is protected in the whole casting process, and a neutral covering agent is protected; by adopting the method, the qualification rate of the sulfur content of the steel smelting components can reach 100 percent, and meanwhile, a basis is provided for the production of other sulfur-containing non-quenched and tempered steels.
Description
Technical Field
The invention relates to the technical field of steel smelting, in particular to a smelting method for stably controlling the sulfur content of non-quenched and tempered steel.
Background
With the development of the Chinese machinery manufacturing industry, the automobile industry, the petrochemical industry and the railway traffic, the requirements of various industries on high-performance materials, particularly special steel, are greatly increased. The development of the steel for the automobile has the prerequisites of technical improvement, structure adjustment, variety optimization, quality improvement and product optimization. Meanwhile, the sustainable development of the special steel production is premised on resource conservation, energy conservation and environmental protection.
The development of manufacturing industry has enabled a large number of high performance materials to be applied in the automotive industry, including the development of high quality, high performance steels. The connecting rod is a key part of an automobile engine, a split type design is generally used in the past, 42CrMo is used, the 42CrMo steel contains high-value molybdenum alloy, the price is higher, and the split type connecting rod has the problem of combination precision. At the beginning of the century, the domestic automobile industry used non-quenched and tempered steel with lower price and higher combination precision for making the expansion-broken connecting rod by using the national experiences of Germany, Japan, America, Italy and the like.
The non-quenched and tempered steel used for the automobile engine expansion-fracture connecting rod has unstable quality after localization, and is mainly characterized in that: after the connecting rod is broken, the deformation is excessive, and the joint surface of the body and the cover is obviously dislocated (stepped); the metallographic phase or the grain size can not meet the requirements; the expansion and the breakage are not easy to happen; the slag is seriously removed after the expansion and the fracture. The reason is analyzed, the content ratio range of various elements of the non-quenched and tempered steel material produced in China is obviously higher than that of foreign materials, particularly wider than the requirements of Germany, Japan, Italy and other countries, and the gap exists in the aspects of component control range and stability. The non-quenched and tempered steel used for the expansion-fracture connecting rod is a material using lower alloy elements, particularly less expensive alloy materials are used, the steel-making cost is lower, but the price is high, the key point is that the proportion range of the content of each alloy element of the steel is narrow, accurate control is needed, great difficulty is brought to smelting, the smelting process of a steel mill is needed to be accurately controlled, the quality stability of the material is ensured, and the localization of the non-quenched and tempered steel for the expansion-fracture connecting rod is comprehensively realized.
The connecting rod has high tensile strength, high torsion resistance and high toughness, but has certain brittleness for expansion fracture, the expansion fracture is not facilitated without certain brittleness, the brittleness is high, the toughness is low, slag is easy to fall, the toughness is high, the expansion fracture is not easy to occur, the expansion fracture material is a contradiction, and how to unify the contradictions is to solve the problem of accurate control of narrow components of each element of steel used for the expansion fracture connecting rod.
The sulfur element is considered as harmful impurities in general special steel, the lower the control is required to be, the better the control is, and in the non-quenched and tempered steel for the spalling connecting rod, a certain content of sulfur is required to be combined with manganese in the steel, so that the sulfur in the steel forms MnS with a higher melting point, a FeS film on a grain boundary is avoided, the hot brittleness of the steel is eliminated, the hot workability is improved, and the non-quenched and tempered steel plays a very beneficial role. Because of its chemical properties in steel, sulfur is very likely to enter slag from molten steel in a reducing atmosphere, resulting in unstable and difficult control of sulfur content in steel. How to accurately and stably control the sulfur content in steel is a difficult problem in producing non-quenched and tempered steel in various steel mills.
Before the invention is put forward, a plurality of smelting methods for producing non-quenched and tempered steel and controlling the sulfur content are provided, and a specially produced refining slag system is mainly used for controlling, but on one hand, the smelting cost is generally higher, and the corrosion to steel ladle refractory is serious; on the other hand, the requirement on the skill level of operators is high, and the actual control is easy to cause large sulfur content fluctuation due to artificial factors.
Disclosure of Invention
The invention aims to provide a smelting method for stably controlling the sulfur content of non-quenched and tempered steel, which ensures that the sulfur content of steel does not have large loss in the processes of LF refining, RH vacuum treatment and continuous casting and pouring by a slag system process control method in the refining process, stably controls the content within the range of 0.010 percent, and ensures that the sulfur content of smelting components in the steel reaches the target of standard control requirements.
The smelting method for stably controlling the sulfur content of non-quenched and tempered steel is characterized by comprising the following steps of:
(1) converter smelting process
Charging scrap steel and a steel material containing Si: 0.30-0.60%, S: the molten iron is qualified at the temperature T of more than or equal to 1300 ℃, the total loading amount of the molten iron and the scrap steel is 140-150T, and the mass percentage content of the molten iron is controlled to be 85-90%;
secondly, a top-bottom combined blowing mode is adopted, dephosphorization in the earlier stage of smelting is enhanced, and high-speed carbon drawing operation is carried out;
thirdly, ensuring that the steel is poured out once, controlling the end point carbon to be 0.20-0.40%, reducing the oxygen activity in the molten steel, and reducing the consumption of deoxidizing materials in the subsequent procedures;
(2) post-furnace and argon station processing
Strengthening the pre-deoxidation operation after the furnace, wherein the alloy components are distributed to the lower limit range of the standard requirement, the middle and upper limit of sulfur distribution, and the bottom blowing argon strength is controlled, so that the secondary pollution of the molten steel exposed to air is reduced, and the total bottom blowing time is 4-6 min;
(3) LF refining
Power transmission and slagging: adding a slag making material before refining and power transmission, adding an alkaline slag making material and an acidic slag making material according to a ratio of 2:1, simultaneously adding 1kg/t of magnesia, controlling the total slag material addition according to 8-10 kg/t, and controlling the mass percentage content of main components of the refining slag as follows: CaO: 45-49% of SiO2：25～30% ，Al2O3: 15-20%, MgO: 9-12%, FeO + MnO: not more than 1.0 percent, controlling R to be 1.8-2.2, namely ensuring that the slag is alkalescent, and adding a diffusion deoxidizer in the power transmission process;
secondly, power is cut off after the slag is completely melted, the slag is adhered, the condition of the cooled slag is further observed, the weakly alkaline slag is gray black and has a small amount of hanging wires, and if the slag is grey white and can be naturally pulverized, acid slag making materials are added for slag mixing;
after the slag is well adjusted, carrying out LF refining normal component adjustment, carrying out slag fine adjustment according to the process sulfur content variation trend, controlling the outbound sulfur content according to the upper limit of the protocol standard, and entering internal control requirements for other components;
(4) RH degassing treatment
In the RH degassing and calcification treatment process, the steel slag is prevented from being stirred greatly in the whole process;
after the components are qualified through inspection and the temperature is proper, hanging the molten steel to a continuous casting platform for casting;
(5) continuous casting
The protective pouring is carried out in the whole continuous casting process, and the tundish covering agent is made of a neutral material.
In the step (3), quartz sand is used as an acid slagging agent, active lime is used as an alkaline slagging agent, and according to the ratio of 2:1 of the alkaline slagging agent to the acid slagging agent, the adding amount of the active lime is 5-7kg/t, and the adding amount of the quartz sand is 2.5-3.5 kg/t.
The fine adjustment of the slag according to the change trend of the sulfur content in the step (3) is specifically as follows: if the first refining sample is analyzed, the reduction amplitude of the sulfur content is more than or equal to 0.003 percent compared with the argon sample of the converter, and then 20-50kg of quartz sand is added; when the reduction of the sulfur content is less than 0.003% compared with the converter argon sample as the first sample of refining, no slag adjustment is required.
In the step (5), the covering agent is made of one or two of neutral vermiculite and carbonized chaff, and can be made of other neutral materials according to the actual conditions of various factories to prevent the molten steel of the alkaline covering agent from generating desulfurization reaction in the continuous casting process.
In the process method, the important point to be controlled is the LF refining process parameters, according to the desulfurization reaction principle ([ FeS ] + (CaO) = (CaS) + (Fe)) in the refining process, the conditions of high alkalinity, reducing atmosphere, high temperature and the like of the slag are favorable for the desulfurization reaction, and the reducing atmosphere and the high temperature are necessary conditions for ensuring the steel quality in the refining process, so the reduction of the alkalinity of the slag becomes an effective means for reducing the sulfur distribution coefficient of the slag in order to inhibit the desulfurization reaction in the refining process.
Through process practice, the basicity R of the refining slag is controlled within the range of 1.8-2.2, so that the relative stable state between sulfur in molten steel and sulfur in the slag can be basically ensured, and the slag is specifically controlled to achieve the basicity measures and principles: the CaO content and the SiO2 content of the quartz sand in the active lime are both about 90 percent, the CaO content and the SiO2 content of the quartz sand are added according to the proportion of 2:1, and the alkalinity R of the slag is basically controlled within the range of 1.8-2.2, namely the slag is ensured to be alkalescent; meanwhile, the reducing characteristic of the slag is carefully controlled, so that the molten steel can be fully deoxidized, and the high desulfurization activity of the slag caused by over-deoxidation is avoided; a certain amount of magnesia is added to ensure that the slag contains about 10 percent of MgO, thereby reducing the corrosion of weakly alkaline slag to the ladle magnesia carbon brick.
The invention has the beneficial effects that:
(1) the qualified rate of the sulfur content of the smelting components of the steel reaches 100 percent;
(2) the whole process and the fine control of the refining slag system are realized, and the stable control of the sulfur content in the refining, vacuum and pouring processes is realized within the range of 0.010 percent;
(3) provides basis for the production of other sulfur-containing non-quenched and tempered steels.
Detailed Description
In order to better explain the technical solution of the present invention, the technical solution of the present invention is further described below with reference to specific examples, which are only exemplary to illustrate the technical solution of the present invention and do not limit the present invention in any way.
Example 1
In the embodiment, according to the agreement standard signed with a user, the sulfur content of the smelting component of the steel needs to be controlled within the range of 0.060-0.070%, and according to the chemical property of sulfur in the steel, the existing method is adopted, so that the smelting component of the steel is extremely unstable in the reducing atmosphere in the refining process, is influenced by deoxidation, slag system and stirring, and is easily caused to have low sulfur content in the smelting component of the steel in the later vacuum treatment and continuous casting processes, and the requirement of the agreement standard cannot be met.
Therefore, in the embodiment, the smelting method for stably controlling the sulfur content of the non-quenched and tempered steel is adopted for smelting, and the method specifically comprises the following steps:
the present embodiment performs smelting by using the existing 130-ton combined blown converter smelting-LF refining-RH degassing-billet continuous casting process flow of a steel plant, and comprises the following steps:
(1) converter smelting process
Charging high-quality plate scrap 20t, molten iron 127t, total charging amount 147t, molten iron ingredient Si: 0.48%, S: 0.026%, temperature T: 1362 deg.C;
secondly, adopting a top-bottom combined blowing mode to carry out high-speed carbon-drawing operation, wherein the adding amount of active lime is 4.1t, and the phosphorus content in the first furnace is 0.024%;
and thirdly, once the steel is poured out, the end point carbon is 0.31 percent.
(2) Post-furnace and argon station processing
Pre-deoxidizing after the furnace, adding 2kg/t of aluminum ingot, distributing other alloy components to the lower limit range of standard requirements, adding 240kg of ferrous sulfide, distributing the sulfur in the steel to about 0.068%, and keeping the total argon blowing time of an argon station for 5min45 s;
(3) LF refining
Power transmission and slagging: 650kg of active lime, 320kg of quartz sand and 150kg of magnesia slag making materials are added before refining and power transmission, and 150kg of calcium carbide is added in batches after power transmission for 5 min;
secondly, transmitting electricity for 12min, observing the thorough melting of the slag, stopping the power supply, observing the slag condition by adhering the slag, replenishing 30kg of quartz sand, taking a slag sample, and rapidly analyzing the components of the slag: CaO: 47.34% of SiO2：25.89% ，Al2O3：17.65%，MgO：10.25%，FeO+MnO：0.74% ，R：1.88；
Thirdly, sampling and analyzing, wherein the sulfur content of the first refining is 0.064%, 20kg of ferrous sulfide is added, other components are normally adjusted, and the sulfur content of the LF refining furnace outlet is 0.067%;
(4) RH degassing treatment
Maintaining pressure and degassing for 11min at RH, adding 400m calcium iron wire for calcification treatment, sampling before ladle lifting, with sulfur content of 0.065%, and lifting molten steel to a continuous casting platform for casting;
(5) continuous casting
The continuous casting adopts a large-ladle argon-sealed protective sleeve and a submerged nozzle for protection and pouring, and the tundish covering agent is compounded with vermiculite and carbonized chaff for heat preservation;
in the middle stage of pouring, finished samples of the tundish are taken, the smelting components all meet the standard requirements of the protocol, and the sulfur content is 0.064%.
Example 2
In the embodiment, the sulfur content of the smelting composition of the steel needs to be controlled within the range of 0.035-0.045%.
The smelting method for stably controlling the sulfur content of the non-quenched and tempered steel comprises the following steps:
(1) converter smelting process
Charging 20t of high-quality scrap steel and 126t of molten iron, wherein the total charging amount is 146t, and the content of molten iron is Si: 0.46%, S: 0.029%, temperature T: 1378 deg.C;
secondly, adopting a top-bottom combined blowing mode to carry out high-speed carbon drawing operation, adding 3.9t of active lime, and taking the phosphorus content in the first furnace to be 0.021%;
thirdly, steel is poured out once, and the end point carbon is 0.23%;
(2) post-furnace and argon station processing
Pre-deoxidizing after the furnace, adding 2kg/t of aluminum ingot, distributing other alloy components to the lower limit range of standard requirements, adding 110kg of ferrous sulfide, distributing the sulfur in the steel to about 0.046%, and keeping the total argon blowing time of an argon station for 5min to 24 s;
(3) LF refining
Power transmission and slagging: 650kg of active lime, 310kg of quartz sand and 150kg of magnesia slag-making materials are added before refining and power transmission, and 150kg of calcium carbide is added in batches after power transmission for 5 min;
transmitting electricity for 12min, observing the slag thoroughly, cutting off the power, observing the slag condition by adhering slag, taking a slag sample, and rapidly analyzing the components of the slag: CaO: 47.26% of SiO2：25.61% ，Al2O3：18.82%，MgO：9.38%，FeO+MnO：0.62% ，R：1.85；
Thirdly, sampling and analyzing, wherein the sulfur content of the first refining is 0.042%, 10kg of ferrous sulfide is added, other components are normally adjusted, and the sulfur content of the LF refining furnace outlet is 0.041%;
(4) RH degassing treatment
Maintaining pressure and degassing for 10min at RH, adding 400m calcium iron wire for calcification treatment, sampling before ladle lifting, with sulfur content of 0.040%, and lifting molten steel to a continuous casting platform for casting;
(5) continuous casting
The continuous casting adopts a large-ladle argon-sealed protective sleeve and a submerged nozzle for protection and pouring, and the tundish covering agent is compounded with vermiculite and carbonized chaff for heat preservation;
in the middle stage of pouring, finished samples of the tundish are taken, the smelting components all meet the standard requirements of the protocol, and the sulfur content is 0.038%.
Example 3
In this example, the sulfur content of the steel melting composition needs to be controlled in the range of 0.015 to 0.025%.
The smelting method for stably controlling the sulfur content of the non-quenched and tempered steel comprises the following steps:
(1) converter smelting process
Charging 23t of high-quality scrap steel, 125t of molten iron, 148t of total charging amount, Si: 0.42%, S: 0.028%, temperature T: 1364 deg.C;
secondly, adopting a top-bottom combined blowing mode to carry out high-carbon-drawing operation, adding 3.9t of active lime, and taking the phosphorus content in the first furnace to be 0.019%;
thirdly, steel is poured out once, and the end point carbon is 0.24%;
(2) post-furnace and argon station processing
Pre-deoxidizing after the furnace, adding 2kg/t of aluminum ingot, distributing other alloy components to the lower limit range of standard requirements, adding no ferrous sulfide, and blowing argon for 5min in an argon station for 17 min17 s;
(3) LF refining
Power transmission and slagging: 650kg of active lime, 300kg of quartz sand and 150kg of magnesia slag-making materials are added before refining and power transmission, and 150kg of calcium carbide is added in batches after power transmission for 5 min;
transmitting electricity for 12min, observing the slag thoroughly, cutting off the power, observing the slag condition by adhering slag, taking a slag sample, and rapidly analyzing the components of the slag: CaO: 49.37% of SiO2：25.22% ，Al2O3：17.62%，MgO：9.59%，FeO+MnO：0.67% ，R：1.96；
Thirdly, sampling and analyzing, wherein the sulfur content of the first refining sample is 0.025 percent, the components are normally adjusted, and the sulfur content before LF wire feeding is 0.023 percent;
(4) RH treatment
Adding 400m calcium iron wire in calcification treatment, sampling before ladle lifting, wherein the sulfur content is 0.022%, and lifting molten steel to a continuous casting platform for pouring;
(5) continuous casting
The continuous casting adopts a large-ladle argon-sealed protective sleeve and a submerged nozzle for protection and pouring, and the tundish covering agent is compounded with vermiculite and carbonized chaff for heat preservation;
in the middle stage of pouring, finished samples of the tundish are taken, the smelting components all meet the requirements of the protocol standard, and the sulfur content is 0.022%.
It can be seen from the above examples that the sulfur content can be strictly controlled within the required range by the method of the present invention, which shows that the method of the present invention has significant effect in controlling the stability of the sulfur content.
Claims (4)
1. A smelting method for stably controlling the sulfur content of non-quenched and tempered steel is characterized by comprising the following steps:
(1) converter smelting process
Charging scrap steel and a steel material containing Si: 0.30-0.60%, S: the molten iron is qualified at the temperature T of more than or equal to 1300 ℃, the total loading amount of the molten iron and the scrap steel is 140-150T, and the mass percentage content of the molten iron is controlled to be 85-90%;
secondly, a top-bottom combined blowing mode is adopted, dephosphorization in the earlier stage of smelting is enhanced, and high-speed carbon drawing operation is carried out;
thirdly, ensuring that the steel is poured out once, controlling the end point carbon to be 0.20-0.40%, reducing the oxygen activity in the molten steel, and reducing the consumption of deoxidizing materials in the subsequent procedures;
(2) post-furnace and argon station processing
Strengthening the pre-deoxidation operation after the furnace, wherein the alloy components are distributed to the lower limit range of the standard requirement, the middle and upper limit of sulfur distribution, and the bottom blowing argon strength is controlled, so that the secondary pollution of the molten steel exposed to air is reduced, and the total bottom blowing time is 4-6 min;
(3) LF refining
Power transmission and slagging: adding a slag making material before refining and power transmission, adding an alkaline slag making material and an acidic slag making material according to a ratio of 2:1, simultaneously adding 1kg/t of magnesia, controlling the total slag material addition according to 8-10 kg/t, and controlling the mass percentage content of main components of the refining slag as follows: CaO: 45-49% of SiO2：25～30% ，Al2O3: 15-20%, MgO: 9-12%, FeO + MnO: not more than 1.0 percent, controlling R to be 1.8-2.2, namely ensuring that the slag is alkalescent, and adding a diffusion deoxidizer in the power transmission process;
secondly, power is cut off after the slag is completely melted, the slag is adhered, the condition of the cooled slag is further observed, the weakly alkaline slag is gray black and has a small amount of hanging wires, and if the slag is grey white and can be naturally pulverized, acid slag making materials are added for slag mixing;
after the slag is well adjusted, carrying out LF refining normal component adjustment, carrying out slag fine adjustment according to the process sulfur content variation trend, controlling the outbound sulfur content according to the upper limit of the protocol standard, and entering internal control requirements for other components;
(4) RH degassing treatment
In the RH degassing and calcification treatment process, the steel slag is prevented from being stirred greatly in the whole process;
after the components are qualified through inspection and the temperature is proper, hanging the molten steel to a continuous casting platform for casting;
(5) continuous casting
The protective pouring is carried out in the whole continuous casting process, and the tundish covering agent is made of a neutral material.
2. The smelting method for stably controlling the sulfur content of non-quenched and tempered steel according to claim 1, wherein the smelting method comprises the following steps: in the step (3), quartz sand is used as an acid slagging agent, active lime is used as an alkaline slagging agent, and according to the ratio of 2:1 of the alkaline slagging agent to the acid slagging agent, the adding amount of the active lime is 5-7kg/t, and the adding amount of the quartz sand is 2.5-3.5 kg/t.
3. The smelting method for stably controlling the sulfur content of non-quenched and tempered steel according to claim 1, wherein the smelting method comprises the following steps: the fine adjustment of the slag according to the change trend of the sulfur content in the step (3) specifically comprises the following steps: if the first refining sample is analyzed, the reduction amplitude of the sulfur content is more than or equal to 0.003 percent compared with the argon sample of the converter, and then 20-50kg of quartz sand is added; when the reduction of the sulfur content is less than 0.003% compared with the converter argon sample as the first sample of refining, no slag adjustment is required.
4. The smelting method for stably controlling the sulfur content of non-quenched and tempered steel according to claim 1, wherein the smelting method comprises the following steps: in the step (5), the covering agent is made of one or two of neutral vermiculite and carbonized chaff, so that the molten steel serving as an alkaline covering agent is prevented from being subjected to desulfurization reaction in the continuous casting process.
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Cited By (3)
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| CN113403448A (en) * | 2021-06-29 | 2021-09-17 | 宝武集团鄂城钢铁有限公司 | Smelting method for quickly raising temperature of refining furnace under condition of low-alkalinity slag |
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