CN102719728A - Technique for producing anti-acid pipeline steel by RH-LF-VD refining - Google Patents
Technique for producing anti-acid pipeline steel by RH-LF-VD refining Download PDFInfo
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Abstract
The invention relates to a technique for producing anti-acid pipeline steel by RH-LF-VD refining. According to the technique, convertor steel making and RH-LF-VD refining techniques are utilized to control the components of molten steel, thereby producing the low-carbon low-sulfur anti-acid (anti-HIC and anti-SCC) pipeline steel. The technique comprises the following steps: predesulfurizing molten iron, smelting in a convertor, carrying out RH vacuum decarburization, carrying out LF heating for desulfurization, carrying out VD vacuum decarburization, carrying out calcium treatment, carrying out soft blowing, continuously casting, and carrying out hot rolling. By using the secondary vacuum refining processes (RH vacuum refining and VD vacuum refining), the invention can reduce the decarburization load of the convertor, lower the oxidizability of the molten steel, eliminate the adverse effect of carburization in the LF furnace refining process, reduce the consumption of a strong deoxidizer, stabilize the production, ensure that the molten steel components are stably controlled within the production target, and satisfy the component control requirements of low carbon, low sulfur and high purity for anti-acid pipeline steel. The carbon content of the finished steel produced by the technical process provided by the invention can be controlled to 0.03%, and the sulfur content can be stably controlled to at most 0.0010%.
Description
Technical field
The invention belongs to the smelting production field of high-level antiacid pipe line steel, relate to the smelting technology that utilizes converter steelmaking and RH-LF-VD refining accurately to control composition in the steel, this technology can alleviate converter decarburization burden greatly; Reduce molten steel oxidation property and tapping temperature, prolong converter lining life, can give full play to LF stove refining desulfuration effect again; The disadvantageous effect of LF process carburetting is eliminated in RH and VD vacuum-treat, reduces strong reductor add-on, reduces deoxidation type inclusion in the steel; Improve purity, the heat composition is even, stable processing technique; Workable, satisfy of the Composition Control requirement of antiacid (anti-HIC and SCC) pipe line steel to low-carbon (LC), low-sulfur and high cleanliness.
Background technology
Pipe-line transportation is to grow distances oil, most economical, the rational mode of transport of Sweet natural gas, has characteristics such as efficient, economic, safe.Transport pipe forward heavy caliber, high pressure direction develop at present.Pipe line steel is requiring high-intensity also require to have simultaneously high low temperature arrest toughness and good welds property.And since the seventies in 20th century, considerable change has taken place in the exploitation condition of various countries' oil, Sweet natural gas, though Sweet natural gas has carried out purifying treatment, H before conveying at present
2The existence of S and water causes that corrosive pipeline is still inevitable.Also have some particular oils, gas to carry geographic pipe line steel also corrosion phenomenon can take place.Therefore pipe line steel is to resistance to corrosion in recent years, and requiring of particularly anti-hydrogen induced cracking (HIC) and sulphide stress corrosion (SCC) is increasingly high.
Hydrogen induced cracking (Hydrogen Induced Crack-HIC) is to be got in the steel by the Wasserstoffatoms that corrosion generates; Accumulate on the interface of MnS and mother metal; Along abnormal structure's expansion of carbon, manganese and phosphorous segregation or along the expansion of banded structure phase boundary,, produce big pressure when Wasserstoffatoms is combined into hydrogen molecule; Be parallel to rolling surface so form, along the crackle of rolling direction.
Sulphide stress corrosion (Stress Corrosion Cracking-SCC) is at H
2S and CO
2Under the effect Deng various acid ions in corrosive medium, soil and the underground water, it is inner that the Wasserstoffatoms that corrosion generates gets into steel through steel surface, and progressively be enriched in region of stress concentration, makes the steel embrittlement also along ftractureing perpendicular to the expansion of force-to-stretch direction.
Pipe line steel composition design philosophy with high anti-HIC and SCC ability is low-carbon (LC), low-sulfur, low-phosphorous, suitable manganese content, microalloying, high cleanliness.Linkage heat controlled rolling and controlled cooling (TMCP) technology reduces macrosegregation and banded structure simultaneously, obtains stable duplex structure, guarantees that pipe line steel has excellent mechanical property and antiacid corrosive nature.
Carbon is strengthening element traditional in the steel, also is most economical element strengthening element.Yet carbon has disadvantageous effect to the toughness of steel, plasticity, weldableness etc.And along with the increase of carbon content, HIC susceptibility increases.Pipe line steel can have good weldableness when carbon content is lower than 0.11%.When carbon content surpasses 0.05%, will cause the segregation of manganese and phosphorus to aggravate, when carbon content less than 0.04% the time, can effectively prevent the generation of HIC.Modern age, the evolution of pipe line steel was the process that constantly reduces carbon content, and general requirement is less than 0.10%, then adopted carbon less than 0.06% Ultra-low carbon content design to needing H.T. or antiacid (anti-HIC and SCC) pipe line steel.The dark decarburization of molten steel mainly is to utilize vacuum refinement to handle, and leans on the oxygen in the molten steel to carry out decarburization, and [C]+[O]={ the CO partial pressure of CO} reaction promotes decarburizing reaction to carry out, and produces low-carbon (LC) or ultra low-carbon steel through reducing.The topmost equipment of molten steel vacuum decarburization is refining of RH vacuum cycle and the refining of VD vacuum stirring.The RH refining has the advantages that speed of response is fast, efficient is high.RH can also carry out oxygen blast forces decarburization, and carbon content of molten steel is reduced to below 0.0010%.The VD refining is a kind of widely used vacuum refinement mode, has good decarburization condition equally, and existing both at home and abroad a lot of steel mills begin to adopt VD to handle to produce utmost point low-carbon (LC) or ultra low-carbon steel, and have obtained the good treatment effect.
Sulphur is the one of the chief elements of harm pipe line steel quality, antiacid (anti-HIC and SCC) performance of its severe exacerbation pipe line steel.Research shows: along with sulphur content in the molten steel increases, crack sensitivity significantly increases; Have only that < 0.0012% the time, HIC obviously reduces when sulphur in the steel.In addition, sulphur also causes the pipe line steel anisotropy, and toughness worsens on horizontal and thickness direction.Pipe line steel is very harsh to the requirement of sulphur content, for X60 and the antiacid pipe line steel of above rank, obtains antiacid goodly (anti-HIC and SCC) performance after satisfying tubulation, C in the steel 0.04%, S < 0.0010% in the while steel.At present the ultra-deep desulfuration technology has mainly been used the thought of system's control, and the sulphur content from the control raw and auxiliary material is set about, and begins to strengthen the desulfurization of each operation from molten iron pretreatment desulfurizing, and whole control is implemented step by step, has obtained good sweetening effectiveness.Molten iron pre-desulfurization is a kind of less expensive, effective sulfur method, in industrial production, is adopted widely.The sweetening power of converter is quite limited.Special under the very low situation of the original sulphur content of molten iron, owing to go into the sulphur that the furnace charges such as slag making material, steel scrap and refractory materials of stove are brought into, the converter process often occurs and return the sulphur phenomenon.Therefore, behind converter tapping, must carry out secondary desulfurization to molten steel.Utilize LF stove heated by electrodes, steel ladle bottom argon blowing, make high basicity slag and carry out dark desulfurization, the finished product sulphur content can be reduced to 0.0005%.
In order to satisfy the requirement of antiacid pipe line steel to molten steel composition, domestic each steel mill's main production process is a vacuum refinement (only through a vacuum refinement) technological process of hot metal pretreatment-top and bottom combined blown converter smelting-external refining (LF refining and RH or VD vacuum-treat combination)-continuous casting at present.The LF sweetening power is more intense, and desulfurization degree can reach 70% ~ 90% when smelting pipe line steel.But there is carburetting contradiction simultaneously in the LF desulfurization.RH or VD vacuum refinement possess effects such as decarburization, the degassing, but cause liquid steel temperature to reduce.Therefore molten steel decarburization and desulfurization and molten steel insulation exist contradiction and restriction of production in the production process.LF-RH technology for example; LF desulfurization heating process is before RH; And the prerequisite of desulfurization is that oxygen will be controlled at low-down level in the steel; Therefore handle at converter tapping and LF and in earlier stage will add reductor molten steel is carried out the dark sweetening effectiveness that deep deoxidation could guarantee LF, when this caused follow-up RH vacuum refinement oxygen decarburization, oxygen content in steel was not enough to carbon is removed to the level of steel grade requirement; Can only force decarburization through oxygen blast in molten steel, in steel, add reductor control oxygen level afterwards again in the scope of regulation.This has not only consumed too much reductor, and the inclusion in the steel is increased, and removes difficulty and strengthens.In addition since the RH operation after, liquid steel temperature is higher when requiring LF stove terminal point, guaranteeing the temperature drop of RH refining process, and because the LF refining process makes molten steel recarburization inevitably, carbon content will be taken off to lower level when therefore also requiring converter tapping.And for RH-LF technology; Because the LF refining process makes molten steel recarburization, therefore require the RH refining process will carbon content in the molten steel be taken off to lower level, could guarantee that carbon content is controlled in the scope of requirement in the finished product molten steel; RH treating processes difficulty strengthens, and molten steel temperature drop is also bigger.Temperature is higher when just requiring converter tapping in order to reduce the LF TRT (LF heated by electrodes process is long more, and molten steel recarburization is more), and carbon content is lower.Also there are identical problem in LF-VD or VD-LF technology.Above technology is for once RH or VD vacuum refinement process all; Promptly increase the converter smelting burden, reduce furnace life; The molten steel purity is relatively poor; Simultaneously for the requirement of LF and RH or VD vacuum refinement process also harshness relatively, promptly to the requirement of the raw material of whole each link of metallurgical technology flow process, equipment, operant level all than higher, to reach the stably manufactured difficulty of low or ultra low levels simultaneously bigger for carbon and sulphur content in the steel.Carbon, sulphur Composition Control instability in the Finished Steel, antiacid (anti-HIC and SCC) performance can not stably reaching standard.
Summary of the invention
In order to address the above problem; The object of the invention provides the LF of the existing vacuum refinement of a kind of elimination (only through a vacuum refinement) to cooperate with RH or LF cooperates the deficiency of explained hereafter low-carbon and low-sulphur steel with VD; Adopt the smelting technology of RH-LF-VD explained hereafter antiacid (anti-HIC and the SCC) pipe line steel of secondary vacuum refining (through the secondary vacuum refining); Stably manufactured satisfies the Composition Control requirement of antiacid pipe line steel to low-carbon (LC), low-sulfur and high cleanliness better.
Technical scheme of the present invention is: the technology of antiacid pipe line steel is produced in a kind of RH-LF-VD refining; Technical process is molten iron pre-desulfurization-converter smelting-RH vacuum decarburization-LF intensification desulfurization-VD vacuum decarburization-calcium processing-soft blow-continuous casting and hot rolling once more, specifically may further comprise the steps:
Molten iron pre-desulfurization: blast-meltedly at first carry out desulfurization,, select paddling process or the desulfurization of hot metal ladle blowing process for use according to the existing molten iron pre-desulfurization processing unit of each production unit through hot metal pretreatment; Behind the molten iron pre-desulfurization EO; Be rich in sulphur in the desulfurization slag, return sulphur, slag is removed totally for avoiding molten iron; The desulfurizing iron rate reaches 90%, goes in the stove molten iron sulphur content less than 0.003%;
Converter smelting: the molten iron that step 1 was handled adopts top and bottom combined blown converter to smelt, and in molten iron, adds 10 ~ 15% low-phosphorous, the low-sulfur steel scrap that account for the molten iron total amount, and whole smelting process is carried out blowing argon gas bottom whole process; Molten steel is fully stirred, so that the composition and the temperature of even molten steel, the endpoint molten steel carbon content is controlled at 0.08% ~ 0.12%; Oxygen level is 0.06% ~ 0.08%, phosphorus content≤0.008%, and tapping temperature is controlled at 1630 ~ 1660 ℃; Adopt the pushing off the slag operation during tapping, in case non-return phosphorus, wherein; The slag making material comprises: lime 50 ~ 65kg/t, light dolomite 15 ~ 25kg/t, and basicity of slag is controlled at 3.5 ~ 4.0;
RH vacuum refinement decarburization deoxidation: utilize the oxygen level of having more than needed in the molten steel behind the converter tapping in the step 2; Through vacuumizing reduction [C]+[O]={ CO partial pressure of CO} reaction; At vacuum pressure less than 100Pa; Adopt big recycle stream flow 1200 ~ 1400L/min to carry out vacuum cycle, treatment time 15min, carbon content of molten steel is controlled at 0.01% ~ 0.03% when reaching terminal point;
The LF slag adopts CaO-Al
2O
3-SiO
2The desulfurization of ternary basic slag system, basicity is controlled at 4.0-6.0, and FeO in the slag and MnO content are less than 0.8%; Adopt the heating of electrode submerged arc, after molten steel adds the LF stove, improve ladle bottom argon blowing rate to 400 ~ 600NL/ min; Treatment time is 35 ~ 45min; The molten steel sulphur content is≤0.0008% during the tapping of LF stove refining terminal point, and carbon content is 0.03% ~ 0.05%, and liquid steel temperature is 1620 ~ 1630 ℃;
The VD vacuum refinement decarburization degassing: the molten steel of above-mentioned steps is carried out the VD vacuum refinement; Less than 100Pa, adopt big recycle stream flow 1200 ~ 1400L/min to carry out vacuum cycle, treatment time 20 ~ 25min at vacuum pressure; Carry out vacuum decarburization, the degassing; Obtaining carbon content is 0.03% ~ 0.04%, and sulphur content is≤0.0010% molten steel, handles qualified molten steel through RH and carries out calcium processing and soft blow; The soft blow time is more than the 12min, must reach the antiacid pipe line steel that the composition of the antiacid performance of pipe line steel requires.
Composition requirement according to target; Utilize this technical process to produce; Carbon content can be stablized and is controlled at 0.03% in the Finished Steel, simultaneously sulphur content can stablize be controlled at≤0.0010%, satisfy of the Composition Control requirement of antiacid (anti-HIC and SCC) pipe line steel to low-carbon (LC), low-sulfur and high cleanliness.
After the molten steel smelting process finishes; Producer can become strand (slab, thin slab or circle base) with customer requirements with pouring molten steel according to self continuous casting installation for casting; Through controlled rolling and controlled cooling (TMCP), antiacid (anti-HIC and SCC) pipeline steel billet that organization of production and performance meet the demands.
Special feature of the present invention is: molten steel promptly is introduced into RH through the converter smelting molten steel and carries out vacuum cycle refining decarburization, deoxidation through the secondary vacuum refining process of RH-LF-VD; Carry out LF stove refining desulfuration afterwards; Get into VD subsequently and carry out the vacuum cycle refining, because the RH vacuum refinement has removed the carbon of the overwhelming majority in the steel, so VD vacuum refinement main purpose is the increment that removes LF refining process carbon, outgases, removes inclusion simultaneously, casts at last.
The invention has the advantages that: utilize the secondary vacuum refinery practice of RH-LF-VD to control composition in the steel, alleviate converter decarburization burden greatly, reduce molten steel oxidation property and tapping temperature, improve furnace life; Eliminate the disadvantageous effect of LF stove refining process carburetting, alleviated LF stove production burden; Reduce the use of strong reductor, reduce nonmetallic inclusionsin steel content; Stablize the whole process production process, guarantee that molten steel composition is controlled in the productive target, satisfy of the Composition Control requirement of antiacid (anti-HIC and SCC) pipe line steel low-carbon (LC), low-sulfur and high cleanliness.
The high-level antiacid pipe line steel market requirement is huge, and only Middle East in 2012 plans that antiacid X60 ~ X65 pipe line steel is 300,000 tons.High-level antiacid pipe line steel production difficulty is big; Market value is high, antiacid pipe line steel than the common pipe line steel market value of same level high 2000 yuan per ton, RH-LF-VD technology guarantees under the prerequisite of the quality of production in the high-level antiacid pipe line steel technology of stably manufactured; The multiple operation comprehensive matching; Through production practice, RH-LF-VD explained hereafter cost is increasing under 120 yuan of prerequisites, and steel grade is produced lumber recovery and brought up to more than 90% by 70% of single vacuum technology; According to 6500 yuan of calculating of antiacid pipe line steel ton steel production cost, the ton steel obtains direct economic benefit (6500/70%-6500/90%)-120=1943 unit.Process application of the present invention will realize the bumper harvests that economic benefit and social resources are practiced thrift.
Technical process of the present invention is fit to produce other simultaneously and requires low-carbon (LC) (Ultra-low carbon) steel grade of low-sulfur (super low sulfur) simultaneously.
The processing parameter of explained hereafter line pipe of the present invention and the contrast of single vacuum refining process are like following table.
Table 1
Embodiment
Below in conjunction with specific embodiment technical scheme of the present invention is described further.
The technology that antiacid pipe line steel is produced in a kind of RH-LF-VD refining of the present invention, technical process are molten iron pre-desulfurization-converter smelting-RH vacuum decarburization-LF intensification desulfurization-VD vacuum decarburization-calcium processing-soft blow-continuous casting and hot rolling once more, specifically may further comprise the steps:
Molten iron pre-desulfurization: blast-melted at first through the desulfurization of hot metal ladle blowing process, sweetening agent is a granule magnesium desulfurizer.Particle magnesium winding-up intensity is 8 ~ 12kg/min, and the carrier gas flux of carrying as pulvis is 120 ~ 150rn
3/ h, according to the initial sulphur content height of molten iron, MAGNESIUM METAL 99 consumption is 0.4 ~ 0.8kg/t, the quantity of slag is generally at 7 ~ 17kg/t.The processing cycle, hot metal temperature drop was 13 ~ 20 ℃ less than 22min, behind the molten iron pre-desulfurization EO, was rich in sulphur in the desulfurization slag, returned sulphur for avoiding molten iron, must slag be removed totally, and the desulfurizing iron rate is reached about 90%, went into the stove molten steel sulfur content less than 0.003%.
Converter smelting: adopt top and bottom combined blown converter to smelt; Whole smelting process is carried out whole process bottom blowing argon gas; Molten steel is fully stirred, so that the composition and the temperature of even molten steel, the converter terminal carbon content is controlled at 0.08% ~ 0.12% and gets final product; Oxygen level is 0.06% ~ 0.08%, phosphorus content≤0.008%.Consider the electrode submerged arc heating molten steel heating effect of LF refining furnace, the converter tapping temperature can reduce relatively, and the converter terminal tapping temperature is controlled at 1630 ~ 1660 ℃, improves converter lining life, prevents Molten Steel over-oxidation.Adopt the pushing off the slag operation during tapping, strict control is the quantity of slag down, in case non-return phosphorus.According to the needs of RH decarburization, adopt weak deoxidation operation during tapping, make oxygen level and carbon content satisfy RH vacuum natural decarbonization process demand.
RH vacuum refinement decarburization deoxidation: in the RH decarburization deoxidization technique, under not oxygen blown condition, vacuumize and carry out the decarburization of nature oxygen; [C]+[O]={ the CO partial pressure of CO} reaction promotes decarburization while deoxygenation to carry out, and carbon content is controlled at about 0.01% when reaching terminal point through reducing.
The dark desulfurization of LF stove refining: the LF slag adopts CaO-Al
2O
3-SiO
2The desulfurization of ternary basic slag system, (FeO+MnO) is less than 0.8% in the slag.Molten steel improves ladle bottom argon blowing rate to 400 ~ 600NL/ min behind the LF stove, the heating of LF stove electrode submerged arc, and desulfurization improves the molten steel purity, alloy fine setting, temperature adjustment.LF stove refining endpoint molten steel sulphur content is≤0.0008%.Because at LF stove refining process molten steel recarburization, LF stove refining endpoint carbon content is controlled at 0.03% ~ 0.05%.The liquid steel temperature that requires control to get into the VD refining station simultaneously is 1620 ~ 1630 ℃, and molten steel overheat is 15 ± 5 ℃ when guaranteeing casting.
The VD vacuum refinement decarburization degassing: because LF stove refining carburetting utilizes the VD pumping high vacuum to carry out vacuum decarburization, the degassing again.VD vacuum refinement terminal point carbon content of molten steel is controlled at 0.03%, and simultaneously sulphur content be controlled at≤0.0008%, reach the composition requirement of the antiacid performance of pipe line steel.Handle qualified molten steel through VD and can carry out calcium processing and soft blow as required, the soft blow time is controlled at more than the 12min.
Continuous casting: casting process requires the whole process protection casting.
Hot rolling: strand is cold through controlled rolling, control, the antiacid pipeline steel billet that organization of production and performance meet the demands.
Antiacid pipe line steel through molten iron pre-desulfurization-converter smelting-RH vacuum refinement-LF refining-VD vacuum refinement-continuous casting and hot rolling explained hereafter; Composition requirement according to target; Carbon content can be stablized and is controlled at 0.03%; Simultaneously sulphur content can stablize be controlled at≤0.0010%, satisfy the specification of quality of antiacid (anti-HIC and SCC) pipe line steel to low-carbon (LC), low-sulfur and high cleanliness.
Embodiment: China certain steel mill of south uses technical process of the present invention and smelts antiacid (anti-HIC and SCC) X65 pipe line steel; Idiographic flow: the antiacid X65 pipe line steel of 28.6mm thickness that molten iron pre-desulfurization-converter smelting-RH refining (decarburization deoxidation)-LF refining (intensification desulfurization)-VD refining (the decarburization degassing)-sheet billet continuous casting-hot rolling is produced; The Finished Steel carbon content is controlled at below 0.03%; Sulphur content is less than 0.0006%, and steel plate reaches antiacid survey requirement fully behind rolling tubulation.The sampling quality contrast sees the following form behind single vacuum (LF-RH) technology and two vacuum (RH-LF-VD) the process pipeline steel pipes.
Table 1
Table 1
The present invention can also have other practical implementation parameter, and the technical scheme that equal replacement of all employings or equivalent transformation form all drops within the scope of requirement protection of the present invention.
Claims (1)
1. technology that antiacid pipe line steel is produced in the RH-LF-VD refining, technical process is molten iron pre-desulfurization-converter smelting-RH vacuum decarburization-LF intensification desulfurization-VD vacuum decarburization-calcium processing-soft blow-continuous casting and hot rolling once more, it is characterized in that, specifically may further comprise the steps:
Molten iron pre-desulfurization: blast-meltedly at first carry out desulfurization,, select paddling process or the desulfurization of hot metal ladle blowing process for use according to the existing molten iron pre-desulfurization processing unit of each production unit through hot metal pretreatment; Behind the molten iron pre-desulfurization EO; Be rich in sulphur in the desulfurization slag, return sulphur, slag is removed totally for avoiding molten iron; The desulfurizing iron rate reaches 90%, goes in the stove molten iron sulphur content less than 0.003%;
Converter smelting: the molten iron that step 1 was handled adopts top and bottom combined blown converter to smelt, and in molten iron, adds 10 ~ 15% low-phosphorous, the low-sulfur steel scrap that account for the molten iron total amount, and whole smelting process is carried out blowing argon gas bottom whole process; Molten steel is fully stirred, so that the composition and the temperature of even molten steel, the endpoint molten steel carbon content is controlled at 0.08% ~ 0.12%; Oxygen level is 0.06% ~ 0.08%, phosphorus content≤0.008%, and tapping temperature is controlled at 1630 ~ 1660 ℃; Adopt the pushing off the slag operation during tapping, in case non-return phosphorus, wherein; The slag making material comprises: lime 50 ~ 65kg/t, light dolomite 15 ~ 25kg/t, and basicity of slag is controlled at 3.5 ~ 4.0;
RH vacuum refinement decarburization deoxidation: utilize the oxygen level of having more than needed in the molten steel behind the converter tapping in the step 2; Through vacuumizing reduction [C]+[O]={ CO partial pressure of CO} reaction; At vacuum pressure less than 100Pa; Adopt big recycle stream flow 1200 ~ 1400L/min to carry out vacuum cycle, treatment time 15min, carbon content of molten steel is controlled at 0.01% ~ 0.03% when reaching terminal point;
The LF slag adopts CaO-Al
2O
3-SiO
2The desulfurization of ternary basic slag system, basicity is controlled at 4.0-6.0, and FeO in the slag and MnO content are less than 0.8%; Adopt the heating of electrode submerged arc, after molten steel adds the LF stove, improve ladle bottom argon blowing rate to 400 ~ 600NL/ min; Treatment time is 35 ~ 45min; The molten steel sulphur content is≤0.0008% during the tapping of LF stove refining terminal point, and carbon content is 0.03% ~ 0.05%, and liquid steel temperature is 1620 ~ 1630 ℃;
The VD vacuum refinement decarburization degassing: the molten steel of above-mentioned steps is carried out the VD vacuum refinement; Less than 100Pa, adopt big recycle stream flow 1200 ~ 1400L/min to carry out vacuum cycle, treatment time 20 ~ 25min at vacuum pressure; Carry out vacuum decarburization, the degassing; Obtaining carbon content is 0.03% ~ 0.04%, and sulphur content is≤0.0010% molten steel, handles qualified molten steel through RH and carries out calcium processing and soft blow; The soft blow time is more than the 12min, must reach the antiacid pipe line steel that the composition of the antiacid performance of pipe line steel requires.
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| CN109161630A (en) * | 2018-09-25 | 2019-01-08 | 湖南华菱湘潭钢铁有限公司 | A kind of smelting process of HIC resistance pipeline steel |
| CN109881095A (en) * | 2019-03-14 | 2019-06-14 | 南京钢铁股份有限公司 | A kind of B grades of acid-resistant pipeline steel plate and smelting process |
| CN111926147A (en) * | 2020-08-04 | 2020-11-13 | 承德建龙特殊钢有限公司 | Method for producing low-sulfur and low-phosphorus steel by using semisteel water |
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| CN113322364B (en) * | 2021-05-20 | 2022-05-17 | 莱芜钢铁集团银山型钢有限公司 | Low-cost smelting method of ultra-high phosphorus molten iron of steel for polar region |
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| TWI560276B (en) * | 2014-06-04 | 2016-12-01 | China Steel Corp | Steel making method |
| CN109161630A (en) * | 2018-09-25 | 2019-01-08 | 湖南华菱湘潭钢铁有限公司 | A kind of smelting process of HIC resistance pipeline steel |
| CN109881095A (en) * | 2019-03-14 | 2019-06-14 | 南京钢铁股份有限公司 | A kind of B grades of acid-resistant pipeline steel plate and smelting process |
| CN111926147A (en) * | 2020-08-04 | 2020-11-13 | 承德建龙特殊钢有限公司 | Method for producing low-sulfur and low-phosphorus steel by using semisteel water |
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