Control method of form of nonmetallic inclusion in steel

Abstract

The invention discloses a control method of the form of a nonmetallic inclusion in steel, and belongs to the field of metallurgy. The control method of the form of the nonmetallic inclusion in the steel comprises a converter melting step, a converter steel tapping step, an LF (ladle furnace) refining step and a continuous casting step, wherein, in the LF refining step, low-basicity refining slag and silicon-containing deoxidizer are added in at least two batches, the silicon-containing deoxidizer is added after the low-basicity refining slag is added each time, the addition of the low-basicity refining slag is between 10 and 18kg/ton steel, and the addition of the silicon-containing deoxidizer is between 1.2 and 3.0kg/ton steel. According to the method, the form of the nonmetallic inclusion (such as Al2O3, CaO, SiO2, MnO and the like) in cord steel, strand steel and other high-quality steel is effectively controlled, and the nonmetallic inclusion in the steel forms a low-melting and plastic composite inclusion, so that the service life of the steel and the drawing performance thereof are improved, and the product quality is increased.

Description

technical field [0001] The invention relates to a method for controlling the form of nonmetallic inclusions in molten steel, belonging to the field of metallurgy. Background technique [0002] With the development of science and technology, various manufacturing industries have more and more stringent requirements for steel materials, such as bearing steel, steel wire rope steel and steel cord steel, silicon steel, etc., and must strictly control the oxygen, nitrogen and other gases and non-metallic materials in the steel. content of inclusions. Some steel types, such as cord steel for automobile tires, in addition to the above requirements, even require that the inclusions in the controlled steel must meet certain shape requirements. [0003] Steel cord is mainly used in industrial fields such as the framework for tire meridian reinforcement and transmission belt. It has the characteristics of high strength and good toughness. The process of producing steel cord is to draw...

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Problems solved by technology

[0006] The control method of refining slag or ladle slag used in the production of cord steel disclosed in the above documents has the following deficiencies: use wollastonite or alloy slag to adjust the composition of the slag, because wollastonite or alloy slag are all made of minerals, and their composition fluctuates Large, slow melting speed, long refining time, difficult to accurately control the final slag composition of refining, using ferrosilicon powder to modify ladle slag, the above problems also exist, and the cost is high; on the other hand, converter tapping Failure to effectively cover and protect the molten steel during the process will increase the probability of the molten steel absorbing nitrogen and oxygen from the air, thus affecting the cleanliness of the molten steel

However, this process cannot effectively remove Al from steel 2 o 3 The shape of the inclusions changes into low-melting aluminate-based inclusions. If the Al2O3 in the produced steel does not transform into low-melting-point aluminate-based composite inclusions, the remaining Al in the steel 2 o 3 Inclusions are prone to wire breakage during the drawing and plying process of the cord steel, which affects the use of the cord steel

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