CN109097525B - Smelting method of high-cleanness chromium-molybdenum steel - Google Patents
Smelting method of high-cleanness chromium-molybdenum steel Download PDFInfo
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- CN109097525B CN109097525B CN201811004864.5A CN201811004864A CN109097525B CN 109097525 B CN109097525 B CN 109097525B CN 201811004864 A CN201811004864 A CN 201811004864A CN 109097525 B CN109097525 B CN 109097525B
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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
- C21C5/52—Manufacture of steel in electric furnaces
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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
- C21C7/0006—Adding metallic additives
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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
- 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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- 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 of high-cleanness chromium-molybdenum steel, which comprises the working procedures of primary smelting, refining and vacuum treatment of an electric furnace; and in the refining process, calcium carbide is used in refining, so that foamed slag can be quickly formed at a low temperature, the heating rate is increased, the refining power consumption is reduced, the air suction of molten steel is reduced, the secondary oxidation of the molten steel is reduced, a certain amount of pure calcium wires are fed after the vacuum is finished, the deep deoxidation effect can be enhanced, and simultaneously, inclusions in steel can be modified, and the damage of the inclusions to the steel is reduced. The invention realizes the improvement of the cleanliness of the chromium-molybdenum steel by brand new novel steel-making processes of firstly compounding weak deoxidation, then feeding aluminum for deep deoxidation, prolonging the vacuum retention time, prolonging the soft blowing time, performing calcium treatment after vacuum and the like, the content of an O element in the obtained molten steel can reach below 10ppm, the thickness and fineness of A, B, C, D types of impurities analyzed in finished steel are respectively less than or equal to 0.5 grade, the uniformity of the steel plate structure is obviously increased, the mechanical property of the steel plate is improved, and the invention has wide application value.
Description
Technical Field
The invention belongs to the technical field of metallurgy, and particularly relates to a smelting method of high-cleanness chromium-molybdenum steel.
Background
Compared with a converter, the control of the electric furnace end point carbon is difficult, and the steel tapping peroxidation condition is common. If a single manganese alloy and aluminum particle pre-deoxidation mode is adopted in the tapping process, aluminum consumption is increased due to early investment of the aluminum strong deoxidizer under the peroxidation condition, the problems that a large amount of aluminum oxide inclusions are difficult to remove and the like are faced, and finally the quality of molten steel is adversely affected. In addition, the tapping condition of the electric furnace is more rigorous for the chromium molybdenum steel with lower requirement on the content of the finished product [ P ].
In recent years, with the increasing improvement of safety and reliability of petrochemical and coal chemical industry equipment by safety supervision departments at home and abroad, the requirements of related design units and manufacturing plants on inclusion control level, flaw detection level, [ O ] content in steel and other cleanliness of medium-high temperature pressure-bearing chromium-molybdenum steel are more and more strict, and part of the requirements are even close to the limit smelting level of the steel.
Therefore, aiming at the current situations of peroxidation and the like commonly existing in electric furnace tapping, technological innovation is correspondingly carried out on a molten steel pre-deoxidation system, a refining deoxidation method and a vacuum treatment mode, and the cleanliness of the chromium-molybdenum molten steel is particularly necessary to be further improved.
Disclosure of Invention
The invention aims to solve the technical problem of providing a smelting method of high-cleanness chromium-molybdenum steel, and particularly relates to a smelting method for improving the purity of chromium-molybdenum molten steel.
In order to solve the technical problems, the invention adopts the technical scheme that: a smelting method of high-cleanness chromium-molybdenum steel comprises the working procedures of primary smelting in an electric furnace, refining and vacuum treatment; in the refining process, the ladle is transferred to a refining position and is added with 0.3-0.4kg/t of steel carbon powder and 1.5-2.0kg/t of steel calcium carbide for pre-deoxidation; in the vacuum treatment process, 1.4-1.6kg/t of steel pure calcium wire is fed into the molten steel after vacuum treatment, and the ladle is used for casting after the normal pressure soft blowing time is more than or equal to 20 min.
According to the initial smelting process of the electric furnace, C is less than or equal to 0.10 percent and P is less than or equal to 0.005 percent after smelting of the electric furnace, steel is normally tapped, molten steel is tapped into a red ladle which is normally circulated, and a pre-deoxidation material, namely, calcium-silicon alloy, of 0.6-0.8kg/t steel is added along with steel flow in the tapping process.
In the refining process, 1.8-2.0 kg/t of aluminum wire is fed once after white slag is discharged, chromium-molybdenum-containing alloy is added for alloying, the total retention time of white slag is more than or equal to 50min, and the ladle is used for slagging off.
According to the vacuum treatment process, 0.5-1.5kg/t of steel lime is added after the VOD seat ladle is subjected to slagging, then the vacuum pumping is performed, and the holding time is more than or equal to 30min when the vacuum degree is below 60 Pa.
According to the vacuum treatment process, the slagging lime is added after the VOD ladle, and the CaO content is more than or equal to 90%.
The content of the O element in the molten steel obtained by the smelting method can reach below 10 ppm.
According to the analysis of the inclusions in the finished steel produced by the smelting method, the thickness and fineness of A, B, C, D inclusions are less than or equal to 0.5 grade.
The high-cleanness chromium-molybdenum steel detection method of the invention has the following standard references: the determination standard of the content of the non-metallic inclusions in the steel refers to GB/T10561-2005 national standard; the determination standard of the oxygen content in the steel refers to the GB/T11261-2006 national standard.
Adopt the produced beneficial effect of above-mentioned technical scheme to lie in: 1. the invention adds the silicon-calcium alloy in the initial smelting tapping process to lead the molten steel to form 12CaO 7Al with low melting point in advance2O3When the production rhythm is short, the full floating of inclusions is facilitated, the production accidents of ladle nozzle nodulation and the like are reduced, and the quality of cast ingots/blanks is improved. 2. According to the invention, the calcium carbide is used in the refining process, so that the foam slag can be quickly formed at a low temperature, the heating rate is improved, the refining power consumption is reduced, the air suction of molten steel is reduced, the secondary oxidation of the molten steel is reduced, the cost is low, and the operability is strong; the deoxidation product generated by the calcium carbide is gas, the deoxidation product is not left in the steel or slag, and the molten steel cannot be subjected to the deoxidation treatmentCauses new pollution and forms protective atmosphere in the refining process, thereby reducing the contact of molten steel and air for oxidation. 3. According to the invention, a certain amount of pure calcium wires are fed after the vacuum is finished, so that the deep deoxidation effect can be enhanced, and simultaneously, the impurities in the steel can be modified, and the harm of the impurities to the steel is reduced. 4. The invention realizes the improvement of the cleanliness of the chromium-molybdenum steel by brand new novel steel-making processes of firstly compounding weak deoxidation, then feeding aluminum for deep deoxidation, prolonging the vacuum retention time, prolonging the soft blowing time, performing calcium treatment after vacuum and the like, the content of O element in the obtained molten steel can reach below 10ppm, the thickness and fineness of A, B, C, D types of impurities analyzed in the finished steel are respectively less than or equal to 0.5 grade, the uniformity of the steel plate structure is obviously increased, the mechanical property of the steel plate is improved, and the invention has wide application value.
Detailed Description
The present invention will be described in further detail with reference to specific examples.
Example 1
The smelting method of the high-cleanness chromium-molybdenum steel 12Cr1MoVR comprises the working procedures of primary smelting, refining and vacuum treatment of an electric furnace, and comprises the following specific process steps:
(1) an electric furnace primary smelting process: c, after the electric furnace smelting is finished: 0.10%, P: 0.005 percent of steel is normally tapped, molten steel is tapped into a red ladle which is normally circulated, and the pre-deoxidized material silicon-calcium alloy of 0.6kg/t steel is added along with steel flow in the tapping process;
(2) a refining procedure: transferring the steel ladle to a refining position, adding 0.3kg/t steel carbon powder and 1.5kg/t steel calcium carbide for pre-deoxidation, feeding 1.8kg/t steel of an aluminum wire at one time after white slag is generated, adding chromium-molybdenum-containing alloy for alloying, keeping the total white slag time for 50min, and lifting the ladle for slagging off;
(3) a vacuum treatment process: and adding 0.5kg/t steel of high-quality lime with 90% of CaO content into the VOD ladle for slagging, vacuumizing, keeping the vacuum degree at 60Pa for 30min, feeding 1.4kg/t steel pure calcium wire into the molten steel after the vacuum is finished, sampling and analyzing the O content in the molten steel to be 9ppm after normal-pressure soft blowing is carried out for 20min, and then hoisting the ladle for casting.
And (3) obtaining a finished steel plate after rolling and heat treatment, sampling on the steel plate, and analyzing, wherein the thickness of A, B, C, D-type inclusions in the steel is analyzed to be less than or equal to 0.5 grade.
Example 2
The smelting method of the high-cleanness chromium-molybdenum steel 12Cr2Mo1R comprises the working procedures of primary smelting, refining and vacuum treatment of an electric furnace, and comprises the following specific process steps:
(1) an electric furnace primary smelting process: c, after the electric furnace smelting is finished: 0.09%, P: 0.005 percent of steel is normally tapped, molten steel is tapped into a red ladle which is normally circulated, and the pre-deoxidation material silicon calcium alloy of 0.65kg/t steel is added along with steel flow in the tapping process;
(2) a refining procedure: transferring the steel ladle to a refining position, adding 0.33kg/t steel carbon powder and 1.7kg/t steel calcium carbide for pre-deoxidation, feeding 1.9kg/t steel of an aluminum wire at one time after white slag is generated, adding chromium-molybdenum-containing alloy for alloying, keeping the total white slag time for 52min, and lifting the ladle for slagging off;
(3) a vacuum treatment process: and adding 0.9kg/t steel of high-quality lime with the CaO content of 91% into the VOD ladle for slagging, vacuumizing, keeping the vacuum degree at 60Pa for 32min, feeding 1.45kg/t steel pure calcium wire into the molten steel after the vacuum is finished, sampling and analyzing the O content in the molten steel to be 8ppm after normal-pressure soft blowing is carried out for 22min, and then hoisting the ladle for casting.
And (3) obtaining a finished steel plate after rolling and heat treatment, sampling on the steel plate, and analyzing, wherein the thickness of A, B, C, D-type inclusions in the steel is analyzed to be less than or equal to 0.5 grade.
Example 3
The smelting method of the high-cleanness chromium-molybdenum steel 12Cr2Mo1VR comprises the working procedures of primary smelting, refining and vacuum treatment of an electric furnace, and comprises the following specific process steps:
(1) an electric furnace primary smelting process: c, after the electric furnace smelting is finished: 0.08%, P: 0.004%, normally tapping, tapping molten steel into a normally-circulated red packet, and adding a pre-deoxidized material silicon-calcium alloy of 0.7kg/t steel along with steel flow in the tapping process;
(2) a refining procedure: transferring the steel ladle to a refining position, adding 0.35kg/t steel carbon powder and 1.85kg/t steel calcium carbide for pre-deoxidation, feeding 1.9kg/t steel of an aluminum wire at one time after white slag is generated, adding chromium-molybdenum-containing alloy for alloying, keeping the total white slag time for 53min, and lifting the ladle for slagging off;
(3) a vacuum treatment process: adding 1.1kg/t of high-quality lime steel with 92% of CaO content into a VOD ladle for slagging, vacuumizing, keeping the vacuum degree at 60Pa for 33min, feeding 1.5kg/t of steel pure calcium wire into molten steel after vacuum is finished, sampling and analyzing the content of O in the molten steel to be 9ppm after normal-pressure soft blowing is carried out for 23min, and then hoisting the ladle for casting.
And (3) obtaining a finished steel plate after rolling and heat treatment, sampling on the steel plate, and analyzing, wherein the thickness of A, B, C, D-type inclusions in the steel is analyzed to be less than or equal to 0.5 grade.
Example 4
The smelting method of the high-cleanness chromium-molybdenum steel 14Cr1MoR comprises the working procedures of primary smelting in an electric furnace, refining and vacuum treatment, and comprises the following specific process steps:
(1) an electric furnace primary smelting process: c, after the electric furnace smelting is finished: 0.07%, P: 0.004%, normally tapping, tapping molten steel to a normally-circulated red ladle, and adding a pre-deoxidization material silicon-calcium alloy of 0.75kg/t steel along with steel flow in the tapping process;
(2) a refining procedure: transferring the steel ladle to a refining position, adding 0.38kg/t steel carbon powder and 1.9kg/t steel calcium carbide for pre-deoxidation, feeding 1.9kg/t steel of an aluminum wire at one time after white slag is generated, adding chromium-molybdenum-containing alloy for alloying, keeping the total white slag time for 54min, and lifting the ladle for slagging off;
(3) a vacuum treatment process: adding 1.3kg/t of high-quality lime steel with 94 percent of CaO content into a VOD ladle for slagging, vacuumizing, keeping the vacuum degree at 60Pa for 34min, feeding 1.55kg/t of steel pure calcium wire into molten steel after vacuum is finished, sampling and analyzing the O content in the molten steel to be 9ppm after soft blowing for 24min under normal pressure, and then hoisting the ladle for casting.
And (3) obtaining a finished steel plate after rolling and heat treatment, sampling on the steel plate, and analyzing, wherein the thickness of A, B, C, D-type inclusions in the steel is analyzed to be less than or equal to 0.5 grade.
Example 5
The smelting method of the high-cleanness chromium-molybdenum steel 15CrMoR comprises the working procedures of primary smelting in an electric furnace, refining and vacuum treatment, and comprises the following specific process steps:
(1) an electric furnace primary smelting process: c, after the electric furnace smelting is finished: 0.06%, P: 0.003 percent of steel is normally tapped, molten steel is tapped into a red ladle which is normally circulated, and the pre-deoxidation material silicon calcium alloy of 0.8kg/t steel is added along with steel flow in the tapping process;
(2) a refining procedure: transferring the steel ladle to a refining position, adding 0.4kg/t of steel carbon powder and 2.0kg/t of steel calcium carbide for pre-deoxidation, feeding 2.0kg/t of aluminum wire after slag is white, adding chromium-molybdenum-containing alloy for alloying, keeping the total retention time of white slag for 55min, and lifting the ladle for slagging off;
(3) a vacuum treatment process: adding 1.5kg/t of high-quality lime steel with the CaO content of 95% into a VOD ladle for slagging, vacuumizing, keeping the vacuum degree at 60Pa for 35min, feeding 1.6kg/t of steel pure calcium wire into molten steel after the vacuum is finished, sampling and analyzing the O content in the molten steel to be 10ppm after 25min of normal-pressure soft blowing, and then hoisting the ladle for casting.
And (3) obtaining a finished steel plate after rolling and heat treatment, sampling on the steel plate, and analyzing, wherein the thickness of A, B, C, D-type inclusions in the steel is analyzed to be less than or equal to 0.5 grade.
Although the present invention has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that: modifications and equivalents may be made thereto without departing from the spirit and scope of the invention and it is intended to cover in the claims the invention as defined in the appended claims.
Claims (3)
1. The smelting method of the high-cleanness chromium-molybdenum steel is characterized by comprising the working procedures of primary smelting in an electric furnace, refining and vacuum treatment; in the electric furnace primary smelting process, C is less than or equal to 0.10 percent and P is less than or equal to 0.005 percent after the electric furnace smelting is finished, normal tapping is carried out, molten steel is tapped into a red ladle which is normally circulated, and a pre-deoxidation material, namely calcium-silicon alloy, of 0.6-0.8kg/t steel is added along with steel flow in the tapping process; in the refining process, the steel ladle is transferred to a refining position and is matched with 0.3-0.4kg/t steel carbon powder and 1.5-2.0kg/t steel calcium carbide for pre-deoxidation, 1.8-2.0 kg/t steel is fed into an aluminum wire for one time after white slag is generated, chromium-molybdenum-containing alloy is added for alloying, the total retention time of white slag is more than or equal to 50min, and the ladle is hung for slag skimming; in the vacuum treatment process, 1.4-1.6kg/t of steel pure calcium wire is fed into molten steel after vacuum treatment, the ladle is used for casting after the normal pressure soft blowing time is more than or equal to 20min, the content of the O element in the obtained molten steel is less than 10ppm, and the impurity content in the finished steel is analyzed, so that the thickness of A, B, C, D types of impurities is less than or equal to 0.5 grade.
2. The method for smelting high-cleanness chromium-molybdenum steel according to claim 1, wherein in the vacuum treatment process, after VOD ladle, 0.5-1.5kg/t of steel lime is added for slagging, and then vacuum pumping is carried out, and the holding time is not less than 30min under the vacuum degree of 60 Pa.
3. The smelting method of high-cleanness chromium-molybdenum steel according to claim 1 or 2, characterized in that in the vacuum treatment process, lime for slagging is added after VOD ladle, and the CaO content is more than or equal to 90%.
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| CN109868406A (en) * | 2019-01-30 | 2019-06-11 | 舞阳钢铁有限责任公司 | A kind of smelting process of high-performance 15CrMoR steel |
| CN110093556A (en) * | 2019-03-26 | 2019-08-06 | 舞阳钢铁有限责任公司 | A kind of end socket 12Cr2Mo1R steel plate and its production method |
| CN110607417B (en) * | 2019-09-30 | 2021-09-24 | 舞阳钢铁有限责任公司 | Method for smelting ultra-low phosphorus chromium molybdenum steel by using dephosphorization slag outside furnace |
| CN114107595A (en) * | 2021-11-03 | 2022-03-01 | 中天钢铁集团有限公司 | Obtaining solid Al2O3Refining process of inclusions |
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| CN101328555B (en) * | 2007-06-22 | 2010-06-30 | 湖北新冶钢有限公司 | Mixing method of high quality low phosphor and sulfur high-alloy steel |
| KR101412566B1 (en) * | 2012-07-31 | 2014-07-02 | 현대제철 주식회사 | Manufacturing method of ultra-low carbon steel using electric furnace |
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| CN108300835A (en) * | 2018-01-04 | 2018-07-20 | 舞阳钢铁有限责任公司 | A method of hydrogen chrome-molybdenum steel field trash is faced in control |
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