Efficient production process of high-standard bearing steel

Abstract

The invention belongs to the technical field of steelmaking processes, and relates to an efficient production process of high-standard bearing steel, A "BOF-RH-CC" process route is adopted. An alloy is melted by an alloy melting furnace, the problem of the large temperature drop of molten steel caused by the addition of a large amount of ferrochrome and other alloys during a tapping process is ingeniously solved, after the tapping is carried out, the molten steel can be directly subjected to vacuum treatment at a RH station, through the elimination of a LF refining furnace, the production efficiency is improved, the problem of slag entrapment in refining slag is solved, meanwhile, the situation that a slag-steel is reacted in a LF slagging submerged arc heating process, so that Al2O3 inclusions are transformed into calcium aluminates that are not conducive to subsequent control is avoided, the inclusions can be controlled in the whole process to be solid Al2O3 with high removing efficiency, after the RH vacuum is performed, the Al2O3 inclusions are efficiently removed, the total oxygen of the molten steel is controlled to 3.0-4.5 ppm, and meanwhile, because the Al2O3 inclusions inthe steel are controlled, the excessive proportion of calcium aluminate inclusions of the steel type B and type Ds is greatly reduced.

Description

technical field [0001] The invention belongs to the technical field of steelmaking technology, and in particular relates to a high-efficiency production technology of high-standard bearing steel. Background technique [0002] Bearings are required to have high resistance to contact fatigue due to high alternating loads during service. The research results show that the lower the total oxygen in the steel and the fewer the number of large-size inclusions in the steel, the higher the fatigue life of the steel. Therefore, bearing steel should not only pursue low total oxygen, but also strictly control the large-size inclusions in the steel. [0003] At present, domestic bearing steel production processes are roughly divided into two categories, one is produced by die casting, such as Chinese patent application number CN201611079071.0 "Smelting method of high-purity bearing steel" and Chinese patent application number CN201710622627.4" A method for manufacturing carburized bear...

AI Technical Summary

Problems solved by technology

②Although aluminum deoxidation is used in the tapping process, the inclusions after tapping are solid Al with high removal efficiency. 2 o 3 , but during the LF treatment of molten steel, due to operations such as slag making and submerged arc heating, the slag steel reacts, making Al 2 o 3 Inclusions are easily transformed into calcium-aluminate, which is not conducive to subsequent control. Even if vacuum treatment is performed, it cannot be removed well, thus increasing the probability of B-type or Ds-type calcium-aluminate inclusions exceeding the standard in steel.

[0005] Although the use of LF refining will bring many problems, for bearing steel with high alloy content, due to the limited control of the tapping temperature of the converter, and the large amount of ferrochrome added during the tapping process, the temperature of the molten steel after tapping is low, and the molten steel can only reach LF furnace is used for heating and alloying treatment. At present, iron and steel enterprises including Xingcheng Special Steel adopt this production process. This method not only reduces the production efficiency of bearing steel, but also does not improve the quality of steel.

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