External refining method for refining high-carbon chromium bearing steel inclusion particles

Abstract

The invention relates to an external refining method for refining high-carbon chromium bearing steel inclusion particles. The method comprises the procedures of material control, BOF, RS, LF, RH, CC and rolling, BOF blowing oxygen decarbonization is further controlled, and the final carbon content ranges from 0.15% to 0.80%. More than 0.5 kg / t aluminum is added to molten steel during steel tappingaccording to an aluminum oxygen equilibrium diagram, so that the oxygen content in the steel after steel tapping is reduced to 30 ppm or below, and the steel tapping temperature is controlled to range from 1600 DEG C to 1700 DEG C. RS drossing operation is carried out after BOF converter smelting steel tapping, and slag in a steel ladle is removed. Refining slag is added during LF refining, the molar fraction of CaO in the refining slag is controlled to range from 40% to 60%, the aluminum content in the steel is controlled to range from 0.03% to 0.07%, and the oxygen content during steel tapping is controlled to be below 10 ppm, and the steel tapping temperature ranges from 1550 DEG C to 1610 DEG C. Argon stirring is carried out in the whole RH vacuum degassing process, and the vacuum state below 100 Pa is kept for 10 min or longer. A continuous casting process which is high in efficiency and low in cost and saves energy is adopted, the production process is perfected, the critical process is optimized, and the particles of fragile DS inclusion of the product are finer.

Description

technical field [0001] The invention belongs to the technical field of production of ultra-high-quality bearing steel, and in particular relates to an out-of-furnace refining production method of high-carbon chromium bearing steel. Background technique [0002] With the rapid development of the national economy, the application of bearings in our country continues to expand, and the existing key bearings for automobiles and railways generally increase the life and reliability requirements. Bearing life is required to travel more than 2.4 million kilometers. In this regard, the research on the relationship between steel quality and bearing life has achieved remarkable results, and the purity of steel is the primary factor affecting the life of bearing steel. [0003] It has been more than 40 years in my country to produce high-carbon chromium bearing steel by refining outside the furnace. With the improvement of equipment and technology level, the purity of steel has made gr...

AI Technical Summary

Problems solved by technology

However, the continuous casting steel or die casting steel produced by the high-efficiency refining method outside the furnace cannot be applied because of the problem of large particles of brittle inclusions.

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