The method of magnetic levitation assisted silicon and its alloys to modify aluminum oxide inclusions in steel

Abstract

The invention relates to the field of smelting and specifically relates to a smelting method for removing a large quantity of inclusions by use of a silicon-containing alloy under the promotion of magnetic levitation and nodulizing the rest inclusion particles. The smelting method is characterized in that 1) pure silicon is used independently as a modifier, and quickly smelted under the action of magnetic levitation to remove inclusions of above 10 microns to a large extent, and the quantity of the residual inclusions are lower than that of treatment by use of other modifiers by two orders of magnitude, 2) the liquid steel is under the influence of the levitation force in a crucible and the pollution on the liquid steel caused by the crucible is reduced, and 3) the liquid steel is stirred violently under the action of the magnetic force, so that the removal of the inclusions in the steel is accelerated and the residual inclusions are modified into smooth spheres. The smelting method has excellent effects on reducing the quantity of large-size inclusions in the steel and nodulizing the rest inclusions to obtain dispersed spherical particles, and a new effective way is provided for the modification of alumina inclusions in the liquid steel.

Description

technical field [0001] The invention relates to the field of iron and steel metallurgy, specifically a smelting method for adding pure silicon or a silicon-containing alloy to steel to modify inclusions in a directional magnetic field and reducing the number of inclusions in the steel. Adding silicon to oxidize the steel The aluminum inclusions are adjusted into spherical particles below 10 microns, and the aluminum oxide inclusions dispersed in the steel are wrapped by low-melting aluminosilicate to form smooth spheres, which greatly improves the life and mechanical properties of the material. Background technique [0002] Non-metallic inclusions in steel have a significant impact on the strength, plasticity, fracture, toughness, cutting performance, and pitting of steel. Since the researcher of Nippon Steel proposed the oxide metallurgy technology at the International Iron and Steel Conference in 1990, people have paid attention to the metallurgy technology in steel. With ...

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Problems solved by technology

[0005] The traditional calcium-silicon treatment process is currently commonly used in smelting aluminum-killed steel in factories. It has a certain degree of effect on the inclusions in the modified steel and the improvement of steel properties, but it also faces some difficulties [3]

For example, since the density of calcium is lower than that of molten steel, it cannot sink into the steel. When adding calcium-containing alloys to the molten pool, it needs to be injected or fed with cored wire to effectively add; the vapor pressure of calcium is very high, and in steel The solubility in the liquid is very small; the oxide inclusions of calcium-based alloy modified aluminum, the modified product obtained by it is not easy to remove, when the liquid phase is formed on the periphery of the inclusion particles, it hinders the denaturation reaction. The product of CaO·Al 2 o 3 Not easily deformed, micro-cracks will be formed during high-grade hard wire cold drawing or rolling, resulting in deterioration of the properties of the steel

[0006] In the traditional process of silicon-calcium alloy treatment, the treatment effect of calcium on inclusions is poor, and a large amount of CaO·Al is formed by inclusions with alumina. 2 o 3 Large number of particles, inclusions, and limited spheroidization

However, under the magnetic levitation assisted process of this patent, the modification effect is greatly improved; further, the modification effect of pure silicon in the process of inclusion treatment is rarely mentioned. It is generally believed that pure silicon is easy to form chain inclusions and should not be used alone use

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