CN-122012856-A - Method for controlling morphology of nonmetallic inclusion in cord steel

Abstract

The invention relates to a method for controlling the morphology of nonmetallic inclusion in cord steel, which comprises the following steps of 1) controlling molten steel components, namely preparing Fe-Si-Mg-Al quaternary alloy and adding the Fe-Si-Mg-Al quaternary alloy in a cored wire mode, 2) controlling refining slag system, wherein the content of w (CaO)/w (SiO 2 )=0.8～1.2,w(MgO)=6%～9%,w(Al 2 O 3 ) is less than 10.0%. According to the invention, according to the quality control requirement of the cord steel, the control function of the nonmetallic inclusion with strong metal magnesium and the converter-refining-continuous casting production process are combined, so that the nonmetallic inclusion of the cord steel is controlled from two aspects of controlling the molten steel component of the cord steel and controlling the refining slag component, and the quality of the cord steel is effectively improved.

Inventors

• HUANG JIAN
• MIN YI
• LIU ZHANGMAN
• Tian Weiyang
• XING WEIYI
• FU QIANG
• LIU ZHENHAI

Assignees

• 本溪北营钢铁（集团）股份有限公司

Dates

Publication Date

20260512

Application Date

20260119

Claims (4)

1. 1. A method of controlling the morphology of nonmetallic inclusions in a cord steel, comprising the steps of: 1) Controlling the molten steel composition; (1) Preparing a quaternary Fe-Si-Mg-Al alloy: adopting a master alloy smelting process to prepare an Fe-Si-Mg-Al quaternary alloy, wherein the content of Si in the Fe-Si-Mg-Al quaternary alloy is 30% -40% by mass percent, the content of Mg is 8.5% -10%, the content of Al is 1.0% -3.0%, the balance is Fe and unavoidable impurities, and the total content of Ca, S and P in the impurities is less than 1.0%; (2) Adding a quaternary alloy of Fe-Si-Mg-Al: The Fe-Si-Mg-Al alloy is added into molten steel in a cored wire mode, after LF refining alloying adjustment, the molten steel is fed into the cored wire when the temperature is controlled to 1580-1620 ℃, the steel is fed in batches with the feeding quantity of 1.8-4.0 m/t, the wire feeding speed is 2.5-3.0 m/s, the wire feeding position is opposite to an air brick at the bottom of a steel ladle, and the soft argon blowing time after wire feeding is more than or equal to 18min; 2) Refining slag system control; Adding slag-forming materials in batches at the earlier stage of LF furnace smelting to form foam-type reducing slag, and keeping the foaming-type reducing slag for more than 20 minutes, wherein the slag components of refining slag are w (CaO)/w (SiO 2 )=0.8～1.2,w(MgO)=6%～9%,w(Al 2 O 3 ) <10.0%, the melting temperature of the refining slag is less than or equal to 1350 ℃, the viscosity of the refining slag is 0.5-1.0 Pa.s, and the surface tension of the refining slag is 0.3-0.5N/m.
2. 2. A method for controlling the morphology of nonmetallic inclusions in a cord steel according to claim 1, wherein the parameters of the cored wire are bransted 9-11 mm in wire diameter, 0.40-0.50 mm in iron sheet thickness, 470-490 g/m in wire weight and 215-240 g/m in core weight.
3. 3. The method of controlling the morphology of nonmetallic inclusions in a steel cord according to claim 1, wherein the cored wire is fed in batches at intervals of greater than 1 minute.
4. 4. A method of controlling the morphology of nonmetallic inclusions in a cord steel as recited in claim 1, wherein the slag-forming material includes lime and aluminum ash balls.

Description

Method for controlling morphology of nonmetallic inclusion in cord steel Technical Field The invention relates to the technical field of production of cord steel, in particular to a method for controlling the morphology of nonmetallic inclusion in cord steel. Background The cord steel is a key material for producing the radial tire frame of the automobile, and can effectively improve the bearing capacity, safety and wear resistance of the tire. The quality of the cord steel is mainly affected by chemical components and nonmetallic inclusions. The chemical components mainly affect the structure and mechanical properties of the cord steel, and with the development and application of modern molten iron pretreatment and external refining technology, the chemical components such as carbon, sulfur, phosphorus and the like in the cord steel are precisely controlled, so that the key for improving the quality of the cord steel at present is the control of nonmetallic inclusions. The nonmetallic inclusion mainly affects the yield, when the cord steel is produced, the drawing is required to be carried out for 200m continuously or the drawing is required to be carried out for 1 ton wire breakage times to be no more than 4 times, so that the nonmetallic inclusion in the steel is required to be controlled closely and strictly, firstly, the types of the nonmetallic inclusion are required to be controlled, the hard nonmetallic inclusion such as Al 2O3, tiN, ti (CN) and the like is not deformed along with a steel matrix in the rolling, drawing and twisting processes, the wire breakage is very easy to occur in the processes of drawing and stranding, so that the plasticization of the inclusion is required to be controlled, secondly, the particle size of the inclusion is required, the monofilament diameter of the steel cord can reach 0.15mm or even finer, and the particle size of the inclusion is required to be controlled to be more than 2% of the monofilament diameter, so that the tiny dispersion of the inclusion is required to be controlled. In order to control the properties of nonmetallic inclusions in the cord steel, various methods including chemical composition control, slag making process optimization, rare earth treatment and the like are tried, so that certain beneficial effects are achieved, the quality control level of the cord steel is effectively improved, but the quality problem of the cord steel caused by nonmetallic inclusions exists in different degrees in industrial production. The magnesium metal has extremely strong inclusion modifying capability due to high activity, and more importantly, the magnesium non-metallic inclusion formed by the magnesium metal has obvious dispersion characteristic and is not easy to polymerize into large-particle inclusion in steel, so the magnesium metal is beneficial to the mechanical property and the processing property of steel. At present, the application of magnesium metal in steel is increasingly emphasized and gradually popularized, but the application of magnesium metal in cord steel is not reported yet. Disclosure of Invention The invention provides a method for controlling the morphology of nonmetallic inclusion in cord steel, which combines the powerful nonmetallic inclusion control function of metal magnesium and converter-refining-continuous casting production process according to the quality control requirement of the cord steel, controls nonmetallic inclusion of the cord steel from two aspects of controlling molten steel components of the cord steel and controlling refining slag components, and effectively improves the quality of the cord steel. In order to achieve the above purpose, the invention is realized by adopting the following technical scheme: a method of controlling the morphology of nonmetallic inclusions in a cord steel, comprising the steps of: 1) Controlling the molten steel composition; (1) Preparing a quaternary Fe-Si-Mg-Al alloy: adopting a master alloy smelting process to prepare an Fe-Si-Mg-Al quaternary alloy, wherein the content of Si in the Fe-Si-Mg-Al quaternary alloy is 30% -40% by mass percent, the content of Mg is 8.5% -10%, the content of Al is 1.0% -3.0%, the balance is Fe and unavoidable impurities, and the total content of Ca, S and P in the impurities is less than 1.0%; (2) Adding a quaternary alloy of Fe-Si-Mg-Al: The Fe-Si-Mg-Al alloy is added into molten steel in a cored wire mode, after LF refining alloying adjustment, the molten steel is fed into the cored wire when the temperature is controlled to 1580-1620 ℃, the steel is fed in batches with the feeding quantity of 1.8-4.0 m/t, the wire feeding speed is 2.5-3.0 m/s, the wire feeding position is opposite to an air brick at the bottom of a steel ladle, and the soft argon blowing time after wire feeding is more than or equal to 18min; 2) Refining slag system control; Adding slag-forming materials in batches at the earlier stage of LF furnace smelting to form foam-type reducing