Argon-passing station pre-refining method for improving purity of bearing steel

Abstract

The invention discloses an argon-passing station pre-refining method for improving the purity of bearing steel, and belongs to the technical field of metal smelting. According to the method, a deoxidizing agent, a carburant, an alloy and pre-refining slag are sequentially added at intervals in the tapping process, the adding amount of aluminum is controlled to be 83%-88% of the total adding amount of aluminum, the adding amount of ferrochrome is controlled to be 90%-95% of the total adding amount of chromium, and the adding amount of silicon is controlled to be 52%-60% of the total adding amount of silicon; before argon station treatment, lime and pre-refining slag are added in the last stage of tapping, so that the ratio of the total slag amount before argon station treatment to the total slag amount of LF refining slag is 0.48-1.00; the method comprises the following steps: pre-refining slag in an argon station, fully melting the pre-refined slag and absorbing inclusions, controlling the slag components after reaction to be 56-60% of omega (CaO), 2-4% of omega (MgO), 28-33% of omega (Al2O3), 3-7% of omega (SiO2) and 0.2-0.6% of omega (FeO + MnO), and controlling the ratio of CaO to (Al2O3.SiO2) to be 0.22-0.38. By means of the method, early removal, generation and size control of the inclusions are achieved.

Description

technical field [0001] The invention relates to the technical field of metal smelting, in particular to a pre-refining method for improving the purity of bearing steel through an argon station. Background technique [0002] The formation of large-sized inclusions is closely related to the control of the metallurgical process. At present, the process route of "primary smelting furnace (converter or electric furnace) + LF refining furnace + RH / VD vacuum refining furnace + casting" is generally adopted in the smelting of bearing steel. The primary smelting furnace The mixing and inclusion of gold in tapping slag, the reaction between high-basic refining slag and molten steel during the refining process, mass transfer and modification of inclusions have become important sources of large-sized inclusions. In order to improve the purity of bearing steel, Chinese patent CN109402327B discloses "An Extra-furnace Refining Production Method for Ultra-Pure High-Carbon Chromium Bearing S...

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Problems solved by technology

Chinese patent CN111793772A discloses "A high-efficiency production process of high-standard bearing steel". This process cancels the LF refining furnace process, and uses an alloy melting furnace to heat the alloy to solve the problem of large temperature drop of molten steel in the tapping process, so that the molten steel after tapping It can go directly to the RH station for vacuum treatment, avoiding slag entanglement in the refining process, and reducing the denaturation of alumina inclusions to calcium aluminate. However, this process does not consider the removal of liquid inclusions formed by slag entanglement during tapping. Moreover, the requirements for controlling the temperature of the converter smelting are high, and the requirements for the end point C are low, which will lead to a substantial increase in the oxygen source in the steel, an increase in the number of inclusions, it is difficult to guarantee the stability of product quality, and there are still deficiencies in the control of purity

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