Method of controlling molten steel pourability under condition of calcium-free treatment

Abstract

The invention provides a method of controlling molten steel pourability under the condition of calcium-free treatment. The method comprises the steps of: (1) carrying out pre-deoxidation before entering an LF (Ladle) furnace, ensuring end point carbon of a converter to be no more than 0.30 percent by virtue of a converter catching carbon technology, adding 2.5Kg of ferro-manganese-aluminum in the process from steel tapping to a steel ladle, and removing at least 95 percent of free oxygen in the molten steel; (2) rapidly producing white slags by virtue of the LF furnace, and ensuring the keeping time of the white slags to be no less than 12minutes; (3) carrying out LF furnace argon blowing-electrifying intelligent control, and intelligently controlling an LF furnace bottom blowing rate by phases and heating powers; and (4) carrying out argon blowing control by phases by virtue of a VD (Vacuum Ladle) furnace. With the adoption of the control method, the amount of molten steel continuous casting furnaces capable of treating without calcium reaches 45, and non-planned nozzle change due to poor molten steel mobility which is caused by reasons of steel breakout, nozzle clogging and the like does not exist.

Description

technical field [0001] The invention belongs to the field of converter steelmaking, and in particular relates to a method for controlling the castability of molten steel under calcium-free treatment conditions. Background technique [0002] The results of experimental research in recent years generally believe that brittle inclusions (Si, Al and Ti-containing nitrides) have a great influence on the contact fatigue life of bearings. The Swedish SKF company once pointed out that the effect of calcium aluminate in oxides is worse than that of alumina. Therefore, in order to reduce the influence of calcium aluminate inclusions on the fatigue life of bearing steel, it is required that the molten steel cannot be treated with calcium. [0003] Laiwu Iron and Steel Special Steel Division adopts a calcium-free treatment process in the production process of bearing steel, but in the casting process, there are often problems such as continuous casting nozzle nodules, unable to raise t...

AI Technical Summary

Problems solved by technology

[0005] In order to overcome the deficiencies of the above technologies, the present invention provides a method for controlling the pourability of molten steel under the condition of calcium-free treatment, so as to avoid the phenomenon of poor fluidity of molten steel caused by reasons such as leaking steel and overholes, resulting in unplanned water changes.

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