Silicon deoxidizing process for silicon-contained steel grades

Abstract

The invention provides a silicon deoxidizing process for silicon-contained steel grades. The silicon deoxidizing process includes the following steps that a silicon iron deoxidizing agent is added when converter tapping is conducted by 1/5, then an aluminum iron deoxidizing agent is added when converter tapping is conducted by 2/3, and for the steel grades, not including the rectangular billet steel grades, requiring the silicon content in steel to be larger than 0.10% by mass fraction, the addition quantity of the silicon iron deoxidizing agent is that 100 kg of the silicon iron deoxidizing agent is added in every 175 tons of steel, and the addition quantity of the aluminum iron deoxidizing agent is that 100-200 kg of the aluminum iron deoxidizing agent is added in every 175 tons of steel; and for the steel grades requiring the silicon content in steel to be 0.06%-0.10% and requiring the manganese content to be lower than 1.00%, the addition quantity of the silicon iron deoxidizing agent is that 30 kg of the silicon iron deoxidizing agent is added in every 175 tons of steel, and the addition quantity of the aluminum iron deoxidizing agent is that 200-300 kg of the aluminum iron deoxidizing agent is added in every 175 tons of steel. According to the silicon deoxidizing process, by adjusting the manner and sequence of deoxidizing alloying, the molten steel quality is improved whole the deoxidizing cost is substantially reduced. The deoxidizing method is good in deoxidizing effect and free of other bad influences; and meanwhile, because compared with aluminum deoxidizing, inclusions formed in molten steel through silicon deoxidizing are easier to float, the nozzle blockage and flow stop probability of the continuous casting working procedure is also decreased.

Description

Technical field [0001] The invention belongs to the technical field of steelmaking production, and particularly relates to a silicon deoxidation process for silicon-containing steel grades. Background technique [0002] At the end of converter steelmaking smelting, molten steel dissolves in excess oxygen. The excess oxygen precipitates when molten steel solidifies to form oxide inclusions and bubbles. The resulting oxide inclusions remain in the steel, which will reduce the steel’s plasticity, impact toughness and other mechanical properties. The high content of oxygen can also produce defects such as subcutaneous bubbles and looseness, and aggravate the harmful effects of sulfur, which directly affects the quality of casting billets and steel products. [0003] At present, the deoxidation method of steel grades smelted in steel plants is generally based on aluminum-iron deoxidation. The advantage of aluminum deoxidation is that the aluminum grain is finer and the deoxidation effec...

AI Technical Summary

Problems solved by technology

[0003] At present, the deoxidation method of steel smelted in steel mills is generally based on aluminum-iron deoxidation. The advantage of aluminum deoxidation is that the aluminum grains are finer and the deoxidation effect is very obvious, but the disadvantage is that the cost of aluminum-iron deoxidation is high, and aluminum deoxidizer is easy to form Al 2 o 3 The inclusions cause water blocking or non-downflow, so a new deoxidation method is needed that can reduce the cost of deoxygenation and solve the problem of water blocking and non-downflow

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