CN111549197A - Continuous casting method for high-aluminum steel plate blank - Google Patents
Continuous casting method for high-aluminum steel plate blank Download PDFInfo
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- CN111549197A CN111549197A CN202010453719.6A CN202010453719A CN111549197A CN 111549197 A CN111549197 A CN 111549197A CN 202010453719 A CN202010453719 A CN 202010453719A CN 111549197 A CN111549197 A CN 111549197A
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- continuous casting
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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
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/10—Supplying or treating molten metal
- B22D11/11—Treating the molten metal
- B22D11/111—Treating the molten metal by using protecting powders
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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
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- Treatment Of Steel In Its Molten State (AREA)
Abstract
The invention discloses a high-aluminum steel slab continuous casting method, which comprises the following steps: s1, primarily smelting in a converter, and stopping blowing the converter to obtain the free oxygen with the target of 500ppm and the upper limit of 600 ppm; s2, refining; s3, continuous casting, namely pouring the refined molten steel into a crystallizer for continuous casting to obtain a continuous casting slab, wherein the casting powder in the crystallizer comprises the following chemical elements in percentage by mass: SiO22：25％～35％、Al2O3：0.5％～1.5％、CaO：35％～45％、MgO：0.6％～1.2％、Na2O：4％～7％、F—：7％～14％、Li2O：1.5％～2.5％、F.C：1.8％～2.8％、T.C：3％～5％、H2O is less than or equal to 0.5 percent, the alkalinity of the covering slag is 1.1 to 1.4, the melting temperature range is 1100 to 1180 ℃, and the viscosity is 0.08 to 0.15 Pa.s. The invention can eliminate the red marks in the continuous casting process of the high-aluminum steel, stabilize the casting process, improve the continuous casting yield, reduce the scrap rate and lighten the longitudinal direction of the plate blankAnd the labor intensity and cost of manual cleaning are reduced.
Description
Technical Field
The invention belongs to the technical field of steel smelting and continuous casting, and particularly relates to a high-aluminum steel plate blank continuous casting method.
Background
High-aluminum steel (Al content is about 0.5%), and the production process of the high-aluminum steel slab is generally converter-refining-continuous casting. In the converter production standard, the blowing-out free oxygen target is 750ppm, the upper limit is 1000ppm, the actual control condition fluctuation is large and reaches 1129ppm at most, and thus the initial Al is caused2O3More inclusions are generated, but the existing production process of the high-aluminum steel plate blank does not process Al in molten steel2O3The content is specially controlled. In continuous castingIn the process, Al in molten steel and SiO in crystallizer casting powder2The reaction is violent, and Al in the high-aluminum steel is simultaneously2O3Higher content of Al2O3The impurities float to the covering slag. Two factors act simultaneously, resulting in SiO in the mold flux2Reduced content of Al2O3The content is increased, the modification of the covering slag is serious, the thermocouple curve of the crystallizer is greatly fluctuated, and the red board alarm is activated when the two thermocouple curves are crossed. In addition, due to the denaturation of the mold flux, the cooling of the meniscus is uneven, deep longitudinal cracks are easy to appear on the plate blank, and the cracks cover the whole plate surface.
The above discussion is intended to introduce the reader to various aspects of art that may be related to various aspects of the present invention, which are described and/or claimed below, and is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention, and is therefore to be understood in this light, and not as an admission of prior art.
Disclosure of Invention
In order to solve the technical problem, the invention provides a high-aluminum steel plate blank continuous casting method.
The purpose of the invention is realized by the following technical scheme: the high-aluminum steel slab continuous casting method comprises the following steps:
s1, primary smelting, wherein the primary smelting is carried out by using a converter, the blowing-out of the converter is stopped, the free oxygen target is 500ppm, and the upper limit is 600 ppm;
s2, refining, namely refining the primarily refined molten steel;
s3, continuous casting, namely injecting the refined molten steel into a tundish, pouring the molten steel into a crystallizer from the tundish, and continuously casting to obtain a continuous casting plate blank, wherein the chemical elements of the casting powder in the crystallizer are as follows by mass percent: SiO22：25％～35％、Al2O3：0.5％～1.5％、CaO：35％～45％、MgO：0.6％～1.2％、Na2O：4％～7％、F—：7％～14％、Li2O：1.5％～2.5％、F.C：1.8％～2.8％、T.C：3％～5％、H2O is less than or equal to 0.5 percent, and the alkalinity of the covering slag is 1.1-1.4, the melting temperature range is 1100-1180 ℃, and the viscosity is 0.08-0.15 Pa.s.
As a further improvement, the covering slag comprises the following chemical elements in percentage by mass: SiO22：32.55％、Al2O3：0.98％、CaO：40.86％、MgO：0.78％、Na2O：5.71％、F—：10.50％、Li2O：1.92％、F.C：2.2％、T.C：4.3％、H2O：0.2％
As a further improvement, the alkalinity of the casting powder is 1.25, the melting point is 1171 ℃, and the viscosity is 0.12 Pa.s.
The invention provides a high-aluminum steel slab continuous casting method, which comprises the following steps: s1, primary smelting, wherein the primary smelting is carried out by using a converter, the blowing-out of the converter is stopped, the free oxygen target is 500ppm, and the upper limit is 600 ppm; s2, refining, namely refining the primarily refined molten steel; s3, continuous casting, namely injecting the refined molten steel into a tundish, pouring the molten steel into a crystallizer from the tundish, and continuously casting to obtain a continuous casting plate blank, wherein the chemical elements of the casting powder in the crystallizer are as follows by mass percent: SiO22：25％～35％、Al2O3：0.5％～1.5％、CaO：35％～45％、MgO：0.6％～1.2％、Na2O：4％～7％、F—：7％～14％、Li2O：1.5％～2.5％、F.C：1.8％～2.8％、T.C：3％～5％、H2O is less than or equal to 0.5 percent, the alkalinity of the covering slag is 1.1 to 1.4, the melting temperature range is 1100 to 1180 ℃, and the viscosity is 0.08 to 0.15 Pa.s. The invention reduces the initial Al through reducing the blowing-out free oxygen of the converter2O3Generating inclusions; SiO in the covering slag2The content reduction inhibits the aluminum-silicon reaction to a certain extent. The combined action of the two factors reduces Al in the casting powder in the casting process2O3The modification degree of the casting powder is reduced, the casting stability is improved, and the red cards are eliminated. By inhibiting the mold flux from denaturing and increasing the alkalinity, the uniformity of meniscus cooling is improved, the incidence of slab longitudinal cracking is reduced, and slab longitudinal cracking is reduced and depth is reduced. The invention can eliminate the red marks in the continuous casting process of the high-aluminum steel, stabilize the casting process, improve the continuous casting yield and reduce the scrapAnd the longitudinal crack of the plate blank can be reduced, and the labor intensity and the cost of manual cleaning are reduced.
Detailed Description
In order to make those skilled in the art better understand the technical solution of the present invention, the present invention is further described in detail below, and it should be noted that the embodiments of the present application and features of the embodiments may be combined with each other without conflict.
The embodiment of the invention provides a high-aluminum steel slab continuous casting method, which comprises the following steps:
and S1, primary smelting, wherein the converter is used for primary smelting, and molten steel obtained by the primary smelting is tapped into a ladle. The blowing-out of the converter is stopped during primary smelting, the free oxygen target is 500ppm, and the upper limit is 600 ppm; aiming at the condition of large fluctuation of blowing-stopping free oxygen of the existing converter, the manufacturing standard is newly established, the blowing-stopping free oxygen target is 500ppm, the upper limit is 600ppm, the lower limit is greatly reduced compared with the prior art, and Al is reduced from the source2O3The purity of the molten steel is improved.
S2, refining, namely refining the primarily refined molten steel, feeding aluminum and alloy for fine adjustment in the refining process, and adjusting the components of the molten steel to the middle limit of the components of the steel grade;
and S3, continuous casting, namely, pouring the refined molten steel into a tundish, pouring the molten steel into a crystallizer from the tundish, and continuously casting to obtain a continuous casting plate blank. In order to promote slow cooling of meniscus, reduce longitudinal cracking of plate blank and inhibit Al-Si reaction, the protecting slag used by a crystallizer is improved, firstly, the alkalinity is improved, secondly, the content of SiO2 is reduced, and the specific formula and physical and chemical indexes of the protecting slag are as follows:
the alkalinity of the covering slag used by the crystallizer is increased to 1.1-1.4 from the existing 0.9-1.2, the slow cooling of a meniscus is promoted, and the longitudinal crack of a plate blank is reduced; the content of SiO2 in the casting powder is reduced, and the aluminum-silicon reaction is inhibited to a certain extent.
The high-aluminum steel plate blank continuous casting method provided by the embodiment of the invention reduces the initial Al through reducing the blowing-out free oxygen of the converter2O3Generating inclusions; SiO in the covering slag2The content reduction inhibits the aluminum-silicon reaction to a certain extent. The combined action of the two factors reduces Al in the casting powder in the casting process2O3The modification degree of the casting powder is reduced, the casting stability is improved, and the red cards are eliminated. By inhibiting the mold flux from denaturing and increasing the alkalinity, the uniformity of meniscus cooling is improved, the incidence of slab longitudinal cracking is reduced, and slab longitudinal cracking is reduced and depth is reduced. The invention can eliminate the red marks in the continuous casting process of the high-aluminum steel, stabilize the casting process, improve the continuous casting yield, reduce the scrap, reduce the longitudinal crack of the plate blank and reduce the labor intensity and the cost of manual cleaning.
In the production embodiment of the invention, the blowing-out of the converter during primary smelting is stopped to obtain the free oxygen target of 500ppm and the upper limit of 600ppm, and the chemical elements of the covering slag comprise the following components in percentage by mass: SiO22：32.55％、Al2O3：0.98％、CaO：40.86％、MgO：0.78％、Na2O：5.71％、F—：10.50％、Li2O：1.92％、F.C：2.2％、T.C：4.3％、H2O: 0.2 percent. The alkalinity of the covering slag is 1.25, the melting point is 1171 ℃, and the viscosity is 0.12 Pa.s. The following is compared with the prior production example before improvement:
production example before improvement: the red cards are high-speed distributed in the pouring process, at least 2 times of card reporting are carried out in each furnace on average, the speed is rapidly reduced to 0.1m/min during card reporting, and the liquid level fluctuation is large. After the red cards occur, double pouring lines appear on the plate blanks due to rapid speed reduction, the double pouring lines are cut by 600mm, so that great waste is caused, and even no complete plate blanks can be used when the red cards occur continuously; the surface of the slab has many longitudinal cracks and is deep, and the whole surface of the slab is covered usually.
Production examples of the invention: no red card is generated, and the liquid level, the position of the stopper rod and the pulling speed are stable; the surface longitudinal crack of the plate blank is obviously reduced, and the longitudinal crack depth is obviously shallow.
The method is implemented when 6 months begin in 2019 of Zhanjiang for Bao steel, 15-furnace high-alumina steel is produced until 8 months, the continuous casting pouring condition is good, and no red alarm occurs. The incidence rate of longitudinal crack of the plate blank is obviously reduced compared with the prior art; wherein no longitudinal cracks are found in 81828 and 83365 furnaces.
The invention is not only suitable for high-aluminum steel, but also suitable for other high-strength steel. And subsequently, the blowing-out of the converter of all high-strength steel is stopped, the free oxygen is strictly controlled, the purity of the molten steel is improved, and certain effect is achieved on improving the surface cracks of the plate blank of the high-strength steel.
In the description above, numerous specific details are set forth in order to provide a thorough understanding of the present invention, however, the present invention may be practiced in other ways than those specifically described herein, and therefore should not be construed as limiting the scope of the present invention.
In conclusion, although the present invention has been described with reference to the preferred embodiments, it should be noted that, although various changes and modifications may be made by those skilled in the art, they should be included in the scope of the present invention unless they depart from the scope of the present invention.
Claims (3)
1. The continuous casting method of the high-aluminum steel slab is characterized by comprising the following steps of:
s1, primary smelting, wherein the primary smelting is carried out by using a converter, the blowing-out of the converter is stopped, the free oxygen target is 500ppm, and the upper limit is 600 ppm;
s2, refining, namely refining the primarily refined molten steel;
s3, continuous casting, namely injecting the refined molten steel into a tundish, pouring the molten steel into a crystallizer from the tundish, and continuously casting to obtain a continuous casting plate blank, wherein the chemical elements of the casting powder in the crystallizer are as follows by mass percent: SiO22：25％～35％、Al2O3：0.5％～1.5％、CaO：35％～45％、MgO：0.6％～1.2％、Na2O：4％～7％、F—：7％～14％、Li2O：1.5％～2.5％、F.C：1.8％～2.8％、T.C：3％～5％、H2O is less than or equal to 0.5 percent, the alkalinity of the covering slag is 1.1 to 1.4, the melting temperature range is 1100 to 1180 ℃, and the viscosity is 0.08 to 0.15 Pa.s.
2. The continuous casting method of the high-aluminum steel slab as claimed in claim 1, wherein the mold flux comprises the following chemical elements in percentage by mass:
SiO2：32.55％、Al2O3：0.98％、CaO：40.86％、MgO：0.78％、Na2O：5.71％、F—：10.50％、Li2O：1.92％、F.C：2.2％、T.C：4.3％、H2O：0.2％。
3. the high-aluminum steel slab continuous casting method according to claim 1 or 2, characterized in that the mold flux has a basicity of 1.25, a melting point of 1171 ℃, and a viscosity of 0.12 pa.s.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010453719.6A CN111549197A (en) | 2020-05-26 | 2020-05-26 | Continuous casting method for high-aluminum steel plate blank |
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| CN202010453719.6A CN111549197A (en) | 2020-05-26 | 2020-05-26 | Continuous casting method for high-aluminum steel plate blank |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113817968A (en) * | 2021-09-07 | 2021-12-21 | 南京钢铁股份有限公司 | Continuous casting production method for square billet of medium-carbon high-aluminum steel |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103014221A (en) * | 2012-12-17 | 2013-04-03 | 莱芜钢铁集团有限公司 | Method for producing high-aluminum steel plate blanks |
| CN105177215A (en) * | 2015-08-28 | 2015-12-23 | 常州东大中天钢铁研究院有限公司 | Efficient production process of high aluminum-alloy-content structure round steel |
| CN108176831A (en) * | 2017-12-28 | 2018-06-19 | 西峡龙成冶金材料有限公司 | A kind of high-aluminum steel continuous crystallizer protecting slag |
| CN108348992A (en) * | 2015-11-05 | 2018-07-31 | 新日铁住金株式会社 | Continuously casting covering slag and continuous casing |
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2020
- 2020-05-26 CN CN202010453719.6A patent/CN111549197A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103014221A (en) * | 2012-12-17 | 2013-04-03 | 莱芜钢铁集团有限公司 | Method for producing high-aluminum steel plate blanks |
| CN105177215A (en) * | 2015-08-28 | 2015-12-23 | 常州东大中天钢铁研究院有限公司 | Efficient production process of high aluminum-alloy-content structure round steel |
| CN108348992A (en) * | 2015-11-05 | 2018-07-31 | 新日铁住金株式会社 | Continuously casting covering slag and continuous casing |
| CN108176831A (en) * | 2017-12-28 | 2018-06-19 | 西峡龙成冶金材料有限公司 | A kind of high-aluminum steel continuous crystallizer protecting slag |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113817968A (en) * | 2021-09-07 | 2021-12-21 | 南京钢铁股份有限公司 | Continuous casting production method for square billet of medium-carbon high-aluminum steel |
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Application publication date: 20200818 |