CN111485066A - Method for controlling inclusions in heavy rail steel by adopting refining slag - Google Patents
Method for controlling inclusions in heavy rail steel by adopting refining slag Download PDFInfo
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- CN111485066A CN111485066A CN202010280766.5A CN202010280766A CN111485066A CN 111485066 A CN111485066 A CN 111485066A CN 202010280766 A CN202010280766 A CN 202010280766A CN 111485066 A CN111485066 A CN 111485066A
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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
- 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
Abstract
The invention discloses a method for controlling inclusions in heavy rail steel by using refining slag, which comprises the following components in percentage by weight: 45 to 60 percent of CaO, 6 to 12 percent of MgO and SiO2:20％～30％，Al2O3The method comprises the steps of less than or equal to 6 percent, less than or equal to 1 percent of FeO and MnO, and the balance of impurities which do not affect slag systems, wherein after slagging is carried out in an L F furnace and the first heating is carried out for 10min, slagging is completed, the components of refined slag meet the requirements, the second heating is carried out for 10-30min according to the temperature requirement of molten steel, then the refined slag is hung in a VD furnace, vacuum degassing is carried out in the VD furnace, the deep vacuum time is more than 15min, the deep vacuum degree is less than 67Pa, then soft blowing is carried out, the liquid level is ensured not to be exposed with the molten steel by controlling the flow of bottom blowing argon, and the soft blowing time is not less than 10 min.
Description
Technical Field
The invention relates to the technical field of ferrous metallurgy, in particular to a method for controlling inclusions in heavy rail steel by using refining slag.
Background
The heavy rail steel takes U75V as an example, the product is mainly applied to 60kg/m and 75kg/m steel rails, higher and higher requirements are provided for the quality and performance of the product, and higher requirements are provided for the quantity, size and the like of the inclusions. The refining slag has very important influence on inclusions in steel, and the refining slag mainly has the following effects: absorbing non-metallic inclusion in steel and preventing secondary oxidation of molten steel. The refining slag needs to have metallurgical properties of purifying molten steel, heating by submerged arc, preventing gas suction, and further removing sulfur, oxygen and the like in steel. The metallurgical reaction in the process of refining the molten steel is carried out between slag steel interfaces, and the quality of the molten steel and the smooth running stability of the refining process are influenced by the refined slag after refining.
The Chinese patent with the application number of 201721435864.1 discloses that a refining slag furnace is adopted to ensure that the free-cutting steel refining slag keeps FeO and MnO in a certain proportion, the proper alkalinity can reach oxygen control, low desulfurization rate and low dephosphorization rate, silicate inclusions in steel can be fully adsorbed, but the removal condition of the inclusions is not quantitatively analyzed. The invention controls the inclusions in the steel by the components of the refining slag aiming at the heavy rail steel, so that the total number of the inclusions in the steel is reduced during refining.
The Chinese patent with application number 201510998643.4 discloses a low-alkalinity refining slag system and a refining process, which ensure the desulfurization of refining, and only analyzes the influence of refining slag on the removal of sulfur, but does not analyze the removal condition of inclusions. The invention achieves the purpose of controlling inclusions in steel in the refining process by optimizing the refining slag system.
The Chinese patent with application number of 201610892473.6 discloses a refining slag for bearing steel, which improves the proportion of oxygen content in the steel less than 8ppm after being used, and eliminates coarse inclusions of B and D. The invention optimizes the refining slag components aiming at the heavy rail steel, reduces the number of inclusions and the proportion of large-particle inclusions in the steel in the refining process and improves the cleanliness of the molten steel.
Disclosure of Invention
The invention aims to provide a method for controlling inclusions in heavy rail steel by using refining slag, so as to solve a series of problems of reducing the number of the inclusions in the steel, reducing the proportion of large-particle inclusions and the like.
In order to solve the technical problems, the invention adopts the following technical scheme:
a method for controlling inclusions in heavy rail steel by adopting refining slag comprises the following components in percentage by weight: 45 to 60 percent of CaO, 6 to 12 percent of MgO and SiO2:20％～30％，Al2O3Less than or equal to 6 percent, less than or equal to 1 percent of FeO and MnO, and the balance of impurities which have no influence on slag systems;
slagging in an L F furnace, heating for the first time for 10min, completing slagging to enable the refining slag components to reach the requirements, heating for the second time for 10-30min according to the temperature requirement of molten steel, and then hoisting to a VD furnace;
vacuum degassing treatment is carried out in a VD furnace, the deep vacuum time is more than 15min, the deep vacuum degree is less than 67Pa, then soft blowing is carried out, the liquid level is ensured not to be exposed with the molten steel by controlling the flow of bottom blowing argon, and the soft blowing time is not less than 10 min.
Further, the refining slag comprises the following components in percentage by weight: 47.89% of CaO, 9.46% of MgO and SiO2:27.88％，Al2O34.52 percent, less than or equal to 0.69 percent of FeO and MnO, and the balance of impurities which have no influence on slag systems.
Further, the refining slag comprises the following components in percentage by weight: 53.07% of CaO, 7.64% of MgO and SiO2:25.83％，Al2O34.93 percent, less than or equal to 0.55 percent of FeO and MnO, and the balance of impurities which do not influence the slag system.
Further, the refining slag comprises the following components in percentage by weight: 48.45 percent of CaO, 10.57 percent of MgO and SiO2:29.27％，Al2O35.49 percent, less than or equal to 0.66 percent of FeO and MnO, and the balance of impurities which have no influence on slag systems.
Further, the refining slag comprises the following components in percentage by weight: 46.21 percent of CaO, 10.94 percent of MgO and SiO2:29.11％，Al2O33.88 percent, less than or equal to 0.69 percent of FeO and MnO, and the balance of impurities which have no influence on slag systems.
Further, the refining slag comprises the components according to the weight percentageThe ratio is as follows: 46.77% of CaO, 10.55% of MgO and SiO2:28.78％，Al2O33.96 percent, less than or equal to 0.68 percent of FeO and MnO, and the balance of impurities which have no influence on slag systems.
Compared with the prior art, the invention has the beneficial technical effects that:
in the refining process, the refining slag is adopted for heavy rail steel to reduce the number of inclusions in the steel, particularly reduce large-particle inclusions, improve the cleanliness of molten steel and improve the powerful guarantee for the subsequent production process.
Analyzing the situation of the inclusions in the steel when L F is in place and VD is out of place, the inclusions in the steel are reduced by 70.33%.
Detailed Description
The implementation steel grade is U75V, the weight of the ladle is 150t, and the number of implementation furnaces is 5.
The chemical components of the refining slag are shown in the following table, wherein the refining slag comprises 45-60% of CaO, 6-12% of MgO, 20-30% of SiO2, less than or equal to 6% of Al2O3, (FeO + MnO) less than or equal to 1%, and the balance of impurities which have no influence on slag systems: p2O5、S、Fe2O3. The chemical components of the refining slag of the furnace 5 are shown in the following table 1:
TABLE 1 refining slag chemical composition
3. Refining production process
L F and VD production process parameters are shown in the following table 2, slagging is completed after a L F furnace is used for slagging and heating for 10min for the first time, the components of refined slag reach the requirements, heating is carried out for 10-30min for the second time according to the temperature requirement of molten steel, then the refined slag is hung to a VD furnace, vacuum degassing is carried out in the VD furnace, the deep vacuum time is more than 15min, the deep vacuum degree is less than 67Pa, then soft blowing is carried out, the bottom blowing argon flow is controlled, the liquid level is ensured not to be exposed to the molten steel, and the soft blowing time is not less than 10 min.
TABLE 2L F production Process parameters
4. Inclusion condition in steel
L F production process steel inclusions are shown in the following table 3, and the analysis of the inclusions in the steel at L F in-position and VD off-position shows that the inclusions in the steel are reduced by 70.33% when L F in-position and 27 VD off-position are in average, thereby showing that the refining slag is beneficial to adsorbing the inclusions in the steel, reducing the level of the inclusions in the steel and improving the quality of molten steel.
TABLE 3 number of inclusions in steels
The above-described embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solutions of the present invention can be made by those skilled in the art without departing from the spirit of the present invention, and the technical solutions of the present invention are within the scope of the present invention defined by the claims.
Claims (6)
1. A method for controlling inclusions in heavy rail steel by using refining slag is characterized by comprising the following steps: the refining slag comprises the following components in percentage by weight: 45 to 60 percent of CaO, 6 to 12 percent of MgO and SiO2:20％～30％，Al2O3Less than or equal to 6 percent, less than or equal to 1 percent of FeO and MnO, and the balance of impurities which have no influence on slag systems;
slagging in an L F furnace, heating for the first time for 10min, completing slagging to enable the refining slag components to reach the requirements, heating for the second time for 10-30min according to the temperature requirement of molten steel, and then hoisting to a VD furnace;
vacuum degassing treatment is carried out in a VD furnace, the deep vacuum time is more than 15min, the deep vacuum degree is less than 67Pa, then soft blowing is carried out, the liquid level is ensured not to be exposed with the molten steel by controlling the flow of bottom blowing argon, and the soft blowing time is not less than 10 min.
2. The method for controlling inclusions in heavy rail steel by using refining slag according to claim 1The method of (2), characterized by: the refining slag comprises the following components in percentage by weight: 47.89% of CaO, 9.46% of MgO and SiO2:27.88％，Al2O34.52 percent, less than or equal to 0.69 percent of FeO and MnO, and the balance of impurities which have no influence on slag systems.
3. The method for controlling inclusions in heavy rail steel using a refining slag according to claim 1, wherein: the refining slag comprises the following components in percentage by weight: 53.07% of CaO, 7.64% of MgO and SiO2:25.83％，Al2O34.93 percent, less than or equal to 0.55 percent of FeO and MnO, and the balance of impurities which do not influence the slag system.
4. The method for controlling inclusions in heavy rail steel using a refining slag according to claim 1, wherein: the refining slag comprises the following components in percentage by weight: 48.45 percent of CaO, 10.57 percent of MgO and SiO2:29.27％，Al2O35.49 percent, less than or equal to 0.66 percent of FeO and MnO, and the balance of impurities which have no influence on slag systems.
5. The method for controlling inclusions in heavy rail steel using a refining slag according to claim 1, wherein: the refining slag comprises the following components in percentage by weight: 46.21 percent of CaO, 10.94 percent of MgO and SiO2:29.11％，Al2O33.88 percent, less than or equal to 0.69 percent of FeO and MnO, and the balance of impurities which have no influence on slag systems.
6. The method for controlling inclusions in heavy rail steel using a refining slag according to claim 1, wherein: the refining slag comprises the following components in percentage by weight: 46.77% of CaO, 10.55% of MgO and SiO2:28.78％，Al2O33.96 percent, less than or equal to 0.68 percent of FeO and MnO, and the balance of impurities which have no influence on slag systems.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010280766.5A CN111485066A (en) | 2020-04-10 | 2020-04-10 | Method for controlling inclusions in heavy rail steel by adopting refining slag |
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| CN202010280766.5A CN111485066A (en) | 2020-04-10 | 2020-04-10 | Method for controlling inclusions in heavy rail steel by adopting refining slag |
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106222362A (en) * | 2016-07-22 | 2016-12-14 | 武汉钢铁股份有限公司 | A kind of method of refining of spring steel |
| CN109082500A (en) * | 2018-08-28 | 2018-12-25 | 包头钢铁（集团）有限责任公司 | The control method of rail hydrogen content |
-
2020
- 2020-04-10 CN CN202010280766.5A patent/CN111485066A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106222362A (en) * | 2016-07-22 | 2016-12-14 | 武汉钢铁股份有限公司 | A kind of method of refining of spring steel |
| CN109082500A (en) * | 2018-08-28 | 2018-12-25 | 包头钢铁（集团）有限责任公司 | The control method of rail hydrogen content |
Non-Patent Citations (1)
| Title |
|---|
| 王玉昌等: "高速重轨钢洁净度与均质性控制关键技术", 《中国冶金》 * |
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