CN110904303A - Smelting method of rail steel - Google Patents
Smelting method of rail steel Download PDFInfo
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- CN110904303A CN110904303A CN201911050370.5A CN201911050370A CN110904303A CN 110904303 A CN110904303 A CN 110904303A CN 201911050370 A CN201911050370 A CN 201911050370A CN 110904303 A CN110904303 A CN 110904303A
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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
-
- 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
-
- 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
-
- 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
-
- 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
-
- 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
- Y02P10/20—Recycling
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Treatment Of Steel In Its Molten State (AREA)
Abstract
The invention relates to a method for smelting rail steel, which comprises the working procedures of molten iron pretreatment, converter smelting, RH refining and bloom continuous casting; the molten iron pretreatment process adopts a deep desulfurization mode, and the S content of the molten iron fed into the furnace is less than 0.001 wt%; in the converter smelting process, the temperature of the converter after the converter is controlled to be 80-100 ℃ above the liquidus line of the steel grade; simultaneously, the main components of Cao and SiO are added after the converter tapping23-5kg of MgO synthetic slag per ton of steel, ensuring that argon is blown for 3-5 minutes after the furnace, the slag is fully melted, and impurities are fully floated. The invention depends on the existing smelting system and raw materials, omits the LF refining process, and adds the raw materials to the existing processThe accurate control of the number greatly improves the production efficiency of rail steel smelting and greatly reduces the cost.
Description
Technical Field
The invention belongs to the technical field of metallurgy, and particularly relates to a method for smelting rail steel.
Background
Railway transportation is developing towards two directions of high speed and heavy weight, and increasingly higher requirements are put on the quality of steel rails. The areas of world-wide view in which rail technology is most developed are europe and america, where europe focuses on the development of high-speed railways and america prefer heavy haul railway transportation. At present, five steel rail production enterprises are in common in China, and the yield and the quality of the steel rail can meet the requirements of the development of the domestic railways.
However, domestic high-speed rail and railway construction peak periods are passed, and the yield of the domestic existing production line is supersaturated relative to the market. The existing market cannot completely digest the yield of the related steel rail plants, so the price of the steel rail is certainly influenced by market saturation in the next step, and the corresponding profit is gradually compressed. At present, how to reduce the production cost of ton steel while ensuring that the quality of the steel rail does not influence the driving safety of a train is a problem to be solved urgently in each steel mill.
The traditional steel rail smelting process comprises molten iron pretreatment, converter smelting, LF refining, RH refining and bloom continuous casting; the steel rail smelting period in the existing route is long, and the production cost is high due to material resistance, power consumption, production efficiency and the like.
Therefore, from the production cost of the steel rail, the cost influence of the steel making process is the largest, the iron making cost is basically fixed, the steel rolling cost is not changed greatly, only the fluctuation of the steel making cost is large, and the influencing factors include not only alloy, refractory materials, yield and the like, but also the influence of a process route.
Disclosure of Invention
The invention aims to solve the technical problem of providing a rail steel smelting method with low cost and high efficiency, and the method realizes the reduction of the cost while ensuring the quality of the rail steel by improving the existing smelting process route and parameters.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows:
a method for smelting rail steel comprises the working procedures of molten iron pretreatment, converter smelting, RH refining and bloom continuous casting;
in the molten iron pretreatment process, the raw materials of the lime sulfide and the passivated magnesium powder are sprayed into the molten iron, and the optimum ratio of the spraying ratio of the lime sulfide to the passivated magnesium powder is controlled to be 3.5: 1-3: 1, so that the deep desulfurization of the molten iron is realized, and the S content of the molten iron entering the furnace is ensured to be less than 0.001 wt%;
in the converter smelting process, the temperature after the converter is controlled to be 80-100 ℃ above the liquidus line of the steel grade; simultaneously, the main components of Cao and SiO are added after the converter tapping23-5kg of MgO synthetic slag per ton of steel, ensuring that argon is blown for 3-5 minutes after the furnace, the slag is fully melted, and impurities are fully floated.
In the RH refining process, after RH treatment is finished, the soft blowing time is more than 15 minutes, so that impurities are fully floated;
in the continuous casting process, a capping measure is adopted in the ladle in the casting process, so that the temperature drop in the process is reduced.
In the smelting method of the rail steel, in the converter smelting process, the main components of Cao and SiO are added after the steel is tapped from the converter23-5kg of MgO synthetic slag per ton of steel, wherein the synthetic slag comprises the following components in percentage by mass: CaO: 38-52% of SiO2：40-50%，MgO≤8%，P≤0.08%，S≤0.15%，CaF2≤5%。
In the traditional smelting process, LF plays a vital role, and has the important roles of warming, adjusting components and removing impurities of molten steel after the converter is primarily smelted, and providing molten steel with high cleanliness and moderate temperature for subsequent RH, so that the LF plays a very important role in the whole molten steel smelting process. The invention develops a new method, carries out the pre-desulfurization treatment of the molten iron by adopting a deep desulfurization mode, sprays the raw materials of the lime sulfide and the passivated magnesium powder into the molten iron, and controls the optimal proportion of the spraying proportion of the lime sulfide and the passivated magnesium powder to be 3.5:1 to 3:1 so as to realize the deep desulfurization of the molten iron and reduce the S content in the molten iron; in the converter process, the steel tapping temperature is increased, the synthetic slag is added after steel tapping to rapidly form slag, the argon blowing time is prolonged, and impurities are promoted to float upwards; in RH vacuum refining, the innovation of rail steel smelting process is realized by prolonging soft blowing time and further promoting the floating of impurities in molten steel and other process optimization, and the tasks of heating, desulfurizing, removing impurities, adjusting components and the like of LF in the original smelting process are successfully decomposed into molten iron desulfurizing, converter smelting and RH processing processes, so that the production efficiency is greatly improved on the premise of ensuring the quality.
Adopt the produced beneficial effect of above-mentioned technical scheme to lie in:
the invention depends on the existing smelting system and raw materials, saves the LF refining process, greatly improves the production efficiency of rail steel smelting and greatly reduces the cost by accurately controlling the existing process parameters. The method does not additionally increase the production cost, is simple and convenient to operate, has a stable effect, provides technical support for rail steel smelting cost and quality control, and has a wide application prospect.
Detailed Description
The present invention will be described in further detail with reference to specific examples.
Example 1
The steel for a certain rail comprises the following main components of 0.67-0.76wt% of C, 0.15-0.58 wt% of Si, 0.70-1.20 wt% of Mn, less than or equal to 0.030wt% of P, less than or equal to 0.025wt% of S, 120-ton top-bottom combined blown converter and 120-ton RH vacuum refining, and comprises the following steps: the S content of the molten iron fed into the converter after the molten iron is pre-desulfurized is 0.0009wt%, the temperature of the molten steel after the converter tapping is controlled to be 95 ℃ above the liquidus line of steel, 600kg of synthetic slag is added after the converter tapping, and the synthetic slag comprises the following components in percentage by mass: CaO: 38% of SiO2：50%，MgO：7%, P:0.05%，S:0.15%，CaF24.8 percent. Argon gas is blown for 5min after tapping, the soft blowing time is 20min after RH treatment, and the whole process of capping is adopted in the continuous casting process. The detection of inclusions after the steel rail is rolled completely meets the requirements of railway standards. Compared with the traditional smelting route, the method has the advantages that,the steel can be saved by 25-35min in each smelting furnace, and the cost is reduced by 50-70 yuan per ton.
Example 2
The embodiment is a certain rail steel, which comprises the following main components of 0.71-0.80 wt% of C, 0.50-0.80 wt% of Si, 0.75-1.05 wt% of Mn, 0.04-0.12% of V, less than or equal to 0.030wt% of P, less than or equal to 0.025wt% of S, 120 tons of top-bottom combined blown converter and 120 tons of RH vacuum refining, and comprises the following steps: the S content of the molten iron fed into the converter after the molten iron is pre-desulfurized is 0.0008wt%, the temperature of the molten steel after the converter tapping is controlled to be 85 ℃ above the liquidus line of steel, 500kg of synthetic slag is added after the converter tapping, and the synthetic slag comprises the following components in percentage by mass: CaO: 42% of SiO2：45%，MgO：8%, P:0.08%，S:0.12%，CaF24.8 percent. Argon is blown for 4min after tapping, the soft blowing time is 18min after RH treatment, and the ladle is covered in the whole process in the continuous casting process. The detection of inclusions after the steel rail is rolled completely meets the requirements of railway standards. Compared with the traditional smelting route, 30-40min can be saved during smelting of steel in each furnace, and the cost is reduced by 60-80 yuan per ton of steel.
Example 3
The steel of the present embodiment is a rail steel, and the main components of the rail steel comprise 0.72-0.80 wt% of C, 0.15-0.58 wt% of Si, 0.70-1.20 wt% of Mn, and Cr: 0.10 to 0.15 percent of P, less than or equal to 0.020 percent of P, less than or equal to 0.025 percent of S, 120 tons of top-bottom combined blown converter and 120 tons of RH vacuum refining, and comprises the following steps: the S content of the molten iron fed into the converter after the molten iron is pre-desulfurized is 0.0009wt%, the temperature of the molten steel after the converter tapping is controlled to be 80 ℃ above the liquidus line of steel, 400kg of synthetic slag is added after the converter tapping, and the synthetic slag comprises the following components in percentage by mass: CaO: 42% of SiO2：47%，MgO：7.5%, P:0.05%，S:0.10%，CaF23.35 percent. Argon is blown for 3min after tapping, the soft blowing time is 15min after RH treatment, and the ladle is covered in the whole process in the continuous casting process. The detection of inclusions after the steel rail is rolled completely meets the requirements of railway standards. Compared with the traditional smelting route, 20-25min can be saved during smelting of steel in each furnace, and the cost is reduced by 30-50 yuan per ton of steel.
Example 4
The steel of this embodiment is a rail steel, and the main components of the steel include C0.50-0.60 wt%, Si 0.20-0.60 wt%, Mn 1.00-1.25 wt%, P not more than 0.025wt%, S not more than 0.025wt%, and 120 tons of top and bottom coated steelThe converter blowing and 120-ton RH vacuum refining method comprises the following steps: the S content of the molten iron fed into the converter after the molten iron is pre-desulfurized is 0.0007wt%, the temperature of the molten steel after the converter tapping is controlled to be 100 ℃ above the liquidus line of steel, 400kg of synthetic slag is added after the converter tapping, and the synthetic slag comprises the following components in percentage by mass: CaO: 45% of SiO2：45%，MgO：7%, P:0.05%，S:0.10%，CaF22.85 percent. Argon is blown for 4min after tapping, the soft blowing time is 18min after RH treatment, and the ladle is covered in the whole process in the continuous casting process. The detection of inclusions after the steel rail is rolled completely meets the requirements of railway standards. Compared with the traditional smelting route, 20-25min can be saved during smelting of steel in each furnace, and the cost is reduced by 30-50 yuan per ton of steel.
Example 5
The steel of the present embodiment is a rail steel, and the main components of the rail steel comprise 0.72-0.80 wt% of C, 0.15-0.58 wt% of Si, 0.70-1.20 wt% of Mn, and Cr: 0.25 to 0.30 percent of the total weight of the components, less than or equal to 0.020 percent of P, less than or equal to 0.025 percent of S, 120 tons of top-bottom combined blown converter and 120 tons of RH vacuum refining, and the method comprises the following steps: the S content of the molten iron fed into the converter after the molten iron is pre-desulfurized is 0.0009wt%, the temperature of the molten steel after the converter tapping is controlled to be 90 ℃ above the liquidus line of steel, 450kg of synthetic slag is added after the converter tapping, and the synthetic slag comprises the following components in percentage by mass: CaO: 50% of SiO2：40%，MgO：5%, P:0.05%，S:0.15%，CaF24.8 percent. Argon is blown for 4min after tapping, the soft blowing time is 20min after RH treatment, and the ladle is covered in the whole process in the continuous casting process. The detection of inclusions after the steel rail is rolled completely meets the requirements of railway standards. Compared with the traditional smelting route, 20-25min can be saved during smelting of steel in each furnace, and the cost is reduced by 30-50 yuan per ton of steel.
Example 6
The steel of the present embodiment is a rail steel, and the main components of the rail steel include 0.90-1.05wt% of C, 0.20-0.60 wt% of Si, 1.00-1.30 wt% of Mn, and Cr: 0.25 to 0.30 percent of P, less than or equal to 0.020 percent of S, 120 tons of top-bottom combined blowing converter and 120 tons of RH vacuum refining, comprising the following steps: the S content of the molten iron fed into the converter after the molten iron is pre-desulfurized is 0.0007wt%, the temperature of the molten steel after the converter tapping is controlled to be 85 ℃ above the liquidus line of steel, 450kg of synthetic slag is added after the converter tapping, and the synthetic slag comprises the following components in percentage by mass: CaO: 45% of SiO2：45%，MgO：6%, P:0.03%，S:0.12%，CaF23.85 percent. . Argon gas is blown for 5min after tapping, soft blowing time is 25min after RH treatment, and the ladle is covered in the whole process in the continuous casting process. The detection of inclusions after the steel rail is rolled completely meets the requirements of railway standards. Compared with the traditional smelting route, 20-25min can be saved during smelting of steel in each furnace, and the cost is reduced by 30-50 yuan per ton of steel.
Claims (4)
1. A rail steel smelting method is characterized by comprising the following steps: comprises the working procedures of molten iron pretreatment, converter smelting, RH refining and bloom continuous casting;
the molten iron pretreatment process adopts a deep desulfurization mode, and the S content of the molten iron fed into the furnace is less than 0.001 wt%;
in the converter smelting process, the temperature after the converter is controlled to be 80-100 ℃ above the liquidus line of the steel grade; simultaneously, the main components of Cao and SiO are added after the converter tapping23-5kg of MgO synthetic slag per ton of steel, ensuring that argon is blown for 3-5 minutes after the furnace, the slag is fully melted, and impurities are fully floated.
2. The method for smelting the rail steel according to claim 1, wherein the method comprises the following steps: in the RH refining process, after RH treatment is finished, the soft blowing time is more than 15 minutes, so that impurities are fully floated;
in the continuous casting process, a capping measure is adopted in the ladle in the casting process, so that the temperature drop in the process is reduced.
3. The method for smelting the rail steel according to claim 1, wherein the method comprises the following steps: in the converter smelting process, the main components of Cao and SiO are added after the converter taps23-5kg of MgO synthetic slag per ton of steel, wherein the synthetic slag comprises the following components in percentage by mass: CaO: 38-45% of SiO2：40-50%，MgO≤8.0% ，P≤0.08%，S≤0.15%，CaF2≤5%。
4. The method for smelting the rail steel according to claim 1, wherein the method comprises the following steps: the molten iron pretreatment process adopts a deep desulfurization mode, adopts the method of blowing the raw materials of the lime sulfide and the passivated magnesium powder into the molten iron, and controls the blowing ratio of the lime sulfide and the passivated magnesium powder to be 3.5: 1-3: 1, so as to realize the deep desulfurization of the molten iron.
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| CN201911050370.5A CN110904303B (en) | 2019-10-31 | 2019-10-31 | Smelting method of rail steel |
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| CN201911050370.5A CN110904303B (en) | 2019-10-31 | 2019-10-31 | Smelting method of rail steel |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114277303A (en) * | 2021-11-23 | 2022-04-05 | 邯郸钢铁集团有限责任公司 | Smelting process for improving size and distribution form of A-type inclusions in heavy rail steel |
| CN115478128A (en) * | 2022-08-22 | 2022-12-16 | 邯郸钢铁集团有限责任公司 | Low-cost and high-efficiency LF refining method |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114277303A (en) * | 2021-11-23 | 2022-04-05 | 邯郸钢铁集团有限责任公司 | Smelting process for improving size and distribution form of A-type inclusions in heavy rail steel |
| CN115478128A (en) * | 2022-08-22 | 2022-12-16 | 邯郸钢铁集团有限责任公司 | Low-cost and high-efficiency LF refining method |
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| CN110904303B (en) | 2022-01-25 |
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