阅读说明：本技术 一种双流板坯连铸机生产高碳钢的方法 (Method for producing high-carbon steel by double-flow slab continuous casting machine ) 是由 厚健龙 曹树卫 欧阳瑜 黄重 郭永谦 孙拓 高新军 向华 徐筱芗 李洪燃 陈丛虎 于 2020-11-12 设计创作，主要内容包括：本发明公开了一种双流板坯连铸机生产高碳钢的方法,该方法具体为：将液态高碳钢钢水通过长水口从钢包罐浇注至中间包罐,再通过浸入式水口浇注至结晶器内,液态钢水在结晶器内冷却凝固,形成厚度均匀的带液芯的坯壳,随着连铸拉速,在二冷室内全部凝固,最后由火焰切割机切割成需要的定尺的板坯。利用该方法在双流板坯连铸机上生产高碳钢,可以减轻高碳钢的中心疏松、中心偏析,减少表面缺陷,提高高碳钢连铸坯质量。(The invention discloses a method for producing high-carbon steel by a double-flow slab continuous casting machine, which comprises the following steps: liquid high-carbon steel molten steel is poured into the crystallizer through the submerged nozzle from the ladle tank to the tundish tank, the liquid molten steel is cooled and solidified in the crystallizer to form a uniform-thickness blank shell with a liquid core, the blank shell is completely solidified in a secondary cooling chamber along with the continuous casting pulling speed, and finally the blank shell is cut into a required fixed-length plate blank by a flame cutting machine. The method for producing the high-carbon steel on the double-flow slab continuous casting machine can reduce the center porosity and the center segregation of the high-carbon steel, reduce the surface defects and improve the quality of the high-carbon steel continuous casting billet.)

1. A method for producing high-carbon steel by a double-flow slab continuous casting machine is characterized by comprising the following steps: liquid high-carbon steel molten steel is poured into the crystallizer through the submerged nozzle from the ladle tank to the tundish tank, the liquid molten steel is cooled and solidified in the crystallizer to form a uniform-thickness blank shell with a liquid core, the blank shell is completely solidified in a secondary cooling chamber along with the continuous casting pulling speed, and finally the blank shell is cut into a required fixed-length plate blank by a flame cutting machine.

2. A method of producing high carbon steel in a dual flow slab caster according to claim 1, wherein said liquid high carbon steel molten steel has the composition: c: 0.48-0.55 wt%, Si: 0.17-0.37 wt%, Mn: 0.50-0.80wt%, P is less than or equal to 0.030wt%, S is less than or equal to 0.030wt%, Als: 0.005-0.020 wt%, and the balance of Fe and inevitable impurities.

3. The method for producing high-carbon steel by using the double-flow slab continuous casting machine as claimed in claim 1, wherein the temperature of the molten steel of the liquid high-carbon steel in the ladle tank is 1540-1555 ℃.

4. The method for producing high-carbon steel by the double-flow slab continuous casting machine according to claim 1, wherein the molten steel of the high-carbon steel is cast from a ladle to a crystallizer in a way of no oxidation protection in the whole process, and specifically comprises the following steps: the ladle pot to the tundish pot adopt a long nozzle, a sealing gasket and argon protection pouring, the contact between the molten steel and the air is isolated by a covering agent in the tundish, the submerged nozzle and the argon protection pouring are adopted from the tundish pot to the crystallizer, and the contact between the molten steel and the air is isolated by high-carbon steel protective slag in the crystallizer.

5. The method for producing high carbon steel in a dual flow slab caster as claimed in claim 1, wherein the temperature of the molten steel of the high carbon steel in said tundish is 1505-1535 ℃.

6. The method for producing high-carbon steel by using the double-flow slab caster as claimed in claim 1, wherein the crystallizer is cooled by cooling water, the wide surface of the cooling water of the crystallizer is 4550-.

7. The method of claim 1, wherein said shell is withdrawn from said mold at a low withdrawal rate in the range of 0.75-0.85 m/min.

8. A method for producing high carbon steel in a dual flow slab caster according to claim 1, wherein said shell is pulled from said mold by a secondary cooling step, said secondary cooling step being a forced cooling step, and the cooling water is in the range of 0.95 to 1.15kg/t steel.

9. The method for producing high carbon steel by using a dual-flow slab caster as claimed in claim 8, wherein electromagnetic stirring is adopted in the secondary cooling process, the electromagnetic stirring current intensity is 450-550A, and the frequency is 5.5-6.5 Hz.

Technical Field

The invention belongs to the technical field of continuous casting, and particularly relates to a method for producing high-carbon steel by a double-flow slab continuous casting machine.

Background

High carbon steels are mainly used for the manufacture of precision tools, also known as tool steels. However, when the high-carbon steel is produced by continuous casting of the double-flow slab, the internal quality of the casting blank is easy to cause problems, such as center porosity, center segregation, internal cracks and the like, and the serious surface of the casting blank has horizontal and longitudinal cracks.

Disclosure of Invention

The invention aims to provide a method for producing high-carbon steel by a double-flow slab continuous casting machine, which can reduce the center porosity and center segregation of the high-carbon steel, reduce the surface defects and improve the quality of a high-carbon steel continuous casting billet by producing the high-carbon steel on the double-flow slab continuous casting machine.

In order to achieve the purpose, the invention adopts the technical scheme that:

a method for producing high-carbon steel by a double-flow slab continuous casting machine comprises the following steps: liquid high-carbon steel molten steel is poured into the crystallizer through the submerged nozzle from the ladle tank to the tundish tank, the liquid molten steel is cooled and solidified in the crystallizer to form a uniform-thickness blank shell with a liquid core, the blank shell is completely solidified in a secondary cooling chamber along with the continuous casting pulling speed, and finally the blank shell is cut into a required fixed-length plate blank by a flame cutting machine.

Preferably, the molten steel of the liquid high-carbon steel produced by the production method comprises the following components: c: 0.48-0.55 wt%, Si: 0.17-0.37 wt%, Mn: 0.50-0.80wt%, P is less than or equal to 0.030wt%, S is less than or equal to 0.030wt%, Als: 0.005-0.020 wt%, and the balance of Fe and inevitable impurities.

Preferably, the temperature of the liquid high-carbon steel molten steel in the ladle pot of the production method is 1540-1555 ℃.

Preferably, in the production method, the molten steel is poured from the ladle to the crystallizer in a non-oxidation protection manner in the whole process, and the method specifically comprises the following steps: the ladle pot to the tundish pot adopt a long nozzle, a sealing gasket and argon protection pouring, the contact between the molten steel and the air is isolated by a covering agent in the tundish, the submerged nozzle and the argon protection pouring are adopted from the tundish pot to the crystallizer, and the contact between the molten steel and the air is isolated by high-carbon steel protective slag in the crystallizer.

In the preferred embodiment of the present invention, the covering agent for a tundish in the above-mentioned method has a low melting point and spreadabilityGood, adsorbable inclusion, good heat preservation effect, little smoke dust, and is not suitable for crusting, and the components are as follows: SiO 2₂：20.0-30.0wt%，CaO：25.0-35.0wt%，Al₂O₃：3.0-4.0wt%，MgO：3.0-7.0wt%，Fe₂O₃：≤1.2wt%，C：30.0-40.0wt%。

Preferably, the high-carbon steel casting powder used in the crystallizer in the method is low-melting-point, high-viscosity and low-alkalinity high-carbon steel casting powder suitable for low drawing speed, the spreadability and the heat preservation performance of the high-carbon steel casting powder are good, the high-carbon steel casting powder is not agglomerated, invariable and stable in consumption in the using process, slag strips are small, and the quality defects of adhesion between a blank shell and a crystallizer copper plate or cracks, slag inclusion, scab and the like caused by the casting powder cannot occur; the consumption is 0.40-0.50kg/t, and the components are as follows: SiO 2₂：27.0-29.0wt%，CaO：29.0-32.0wt%，Al₂O₃：3.0-4.0wt%，NaO：8-11wt%，Fe₂O₃：0.4-0.6wt%，C：6.0-10.0wt%。

Preferably, in the method, the temperature of the molten steel of the high-carbon steel in the tundish is 1505-1535 ℃.

Preferably, the crystallizer in the method adopts cooling water to carry out forced cooling, the wide surface of the cooling water of the crystallizer is 4550-.

Preferably, the method is characterized in that the blank shell is drawn out from the crystallizer at a low drawing speed, and the drawing speed is in a range of 0.75-0.85 m/min.

Preferably, the method adopts secondary cooling for pulling the blank shell out of the crystallizer, wherein the secondary cooling is strong cooling, and the range of cooling water is 0.95-1.15kg/t steel.

Preferably, in the method, the blank shell is pulled out from the crystallizer by secondary cooling, electromagnetic stirring is adopted in the secondary cooling process, the electromagnetic stirring current intensity is 450-550A, and the frequency is 5.5-6.5 Hz.

Compared with the prior art, the invention has the beneficial effects that:

1. the invention adopts the whole process of non-oxidation protection pouring, has stable molten steel quality, low steel inclusion content, stable production in the continuous casting pouring process, no bonding of a blank shell and a crystallizer copper plate, stable crystallizer casting powder performance, undetermined consumption and no casting powder agglomeration.

2. In the continuous casting production process, the invention adopts lower tundish temperature and low casting speed, the crystallizer and secondary cooling are both strong secondary cooling, electromagnetic stirring is adopted, the center segregation of the slab is lighter, the slab has no center looseness and intermediate cracks, and the surface of the slab has no defects of cracks, slag inclusion and the like.

The production method ensures the reliable and stable quality of the high-carbon steel poured by the double-flow slab continuous casting machine.

Detailed Description

The technical solutions and effects of the present invention will be further described with reference to specific examples, but the scope of the present invention is not limited thereto.

Example 1

Within this company, high carbon steel slabs with a thickness of 210mm and a width of 1290mm are produced.

(1) The high-carbon steel comprises the following components: 0.48wt%, Si: 0.28wt%, Mn: 0.63wt%, P: 0.018wt%, S: 0.011wt%, Als: 0.008wt%, and the balance Fe and inevitable impurities.

(2) The temperature of the liquid high-carbon steel molten steel in the ladle pot is 1550 ℃.

(3) The ladle to the tundish adopt a long nozzle, a sealing gasket and argon non-oxidation protection pouring, and a covering agent is manually added on the surface of molten steel in the tundish to isolate the molten steel from air.

(4) Pouring from the tundish to the crystallizer by adopting an immersion nozzle and argon protection, and manually adding high-carbon steel covering slag into the crystallizer to isolate the high-carbon steel covering slag from air, wherein the consumption of the covering slag is 0.42kg/t steel.

(5) The temperature of the molten steel in the tundish is 1518 ℃.

(6) The width of cooling water of the crystallizer is 4550L/min, and the width of cooling water of the crystallizer is 550L/min.

(7) The pulling speed range is 0.85 m/min.

(8) The specific water amount of the second cooling water is as follows: 0.98kg/t steel.

(9) The secondary cooling electromagnetic stirring current intensity is 480A, and the frequency is 5.5 Hz.

The high carbon steel obtained in this example, low power rating, was: the center segregation C is 0.5 grade, has no center porosity, no shrinkage cavity, no middle crack and no other internal defects, and has the surface quality as follows: no surface defects such as longitudinal crack, transverse crack and slag inclusion, and the quality of the product meets the technical requirements.

Example 2

In this company, high carbon steel slabs are produced with a thickness of 230mm and a width of 1290 mm.

(1) The high-carbon steel comprises the following components: 0.50wt%, Si: 0.28wt%, Mn: 0.72wt%, P: 0.016wt%, S: 0.003wt%, Als: 0.011wt%, and the balance Fe and inevitable impurities.

(2) The molten steel temperature of the liquid high-carbon steel in the ladle tank is 1540 ℃.

(3) The ladle to the tundish adopt a long nozzle, a sealing gasket and argon non-oxidation protection pouring, and a covering agent is manually added on the surface of molten steel in the tundish to isolate the molten steel from air.

(4) Pouring from the tundish to the crystallizer by adopting an immersion nozzle and argon protection, and manually adding high-carbon steel covering slag into the crystallizer to isolate the high-carbon steel covering slag from air, wherein the consumption of the covering slag is 0.41kg/t steel.

(5) The tundish molten steel temperature was 1508 ℃.

(6) The wide surface of the cooling water of the crystallizer is 4650L/min, and the narrow surface is 570L/min.

(7) The pulling rate is 0.75 m/min.

(8) The specific water amount of the second cooling water is as follows: 1.10kg/t steel.

(9) The secondary cooling electromagnetic stirring current intensity is 500A, and the frequency is 6.0 Hz.

The high carbon steel obtained in this example, low power rating, was: the center segregation C is 0.5 grade, has no center porosity, no shrinkage cavity, no middle crack and no other internal defects, and has the surface quality as follows: no surface defects such as longitudinal crack, transverse crack and slag inclusion, and the quality of the product meets the technical requirements.

Example 3

In this company, high carbon steel slabs are produced with a thickness of 230mm and a width of 1290 mm.

(1) The high-carbon steel comprises the following components: 0.54wt%, Si: 0.28wt%, Mn: 0.68wt%, P: 0.015wt%, S: 0.008wt%, Als: 0.015wt%, the balance being Fe and inevitable impurities.

(2) The liquid high-carbon steel molten steel temperature of the ladle tank is 1545 ℃.

(3) The ladle to the tundish adopt a long nozzle, a sealing gasket and argon non-oxidation protection pouring, and a covering agent is manually added on the surface of molten steel in the tundish to isolate the molten steel from air.

(4) Pouring from the tundish to the crystallizer by adopting an immersion nozzle and argon protection, and manually adding high-carbon steel covering slag into the crystallizer to isolate the high-carbon steel covering slag from air, wherein the consumption of the covering slag is 0.43kg/t steel.

(5) The temperature of the molten steel in the tundish is 1510 ℃.

(6) The width of cooling water of the crystallizer is 5000L/min, and the narrow surface is 600L/min.

(7) The pulling speed range is 0.80 m/min.

(8) The specific water amount of the second cooling water is as follows: 1.15kg/t steel.

(9) The secondary cooling electromagnetic stirring current intensity is 550A, and the frequency is 6.5 Hz.

The high carbon steel obtained in this example, low power rating, was: the center segregation C is 1.0 grade, has no center porosity, no shrinkage cavity, no middle crack and no other internal defects, and has the surface quality as follows: no surface defects such as longitudinal crack, transverse crack and slag inclusion, and the quality of the product meets the technical requirements.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.