Smelting method of sulfur bearing steel

Abstract

The invention relates to the technical field of ferrous metallurgy, in particular to a smelting method of sulfur bearing steel. The smelting method of the sulfur bearing steel comprises steps as follows: a, lime, a slag modifier and a compound deoxidizer are added to steel tapping slag of an electric furnace, so that the content of CaO is 30wt%-45wt% and the content of Al2O3 is 35wt%-45wt% in the slag; b, molten steel is sent into an LF (ladle furnace), the LF is powered on for slagging, the slag modifier is added to control the flowability of furnace slag, the furnace slag is turned into white slag through diffusion and deoxygenation, sulfur is fed into the LF for sulfur alloying, and calcification treatment is performed during LF steel tapping; c, slagging-off operation is performed after smelting by the LF is completed; d, the molten steel is transferred to a VD (vacuum degassing) furnace for smelting, and vacuum treatment is performed; a covering agent is added to a molten steel surface after degassing, and argon gas is adjusted for flexible argon blowing for 15-40 min. The content of S before and after VD treatment changes more slightly, the loss of sulfur in the steel after VD treatment is lower, the loss rate is smaller than or equal to 0.005%, the content of sulfur in molten steel after VD treatment is stably controlled, and stable product quality is obtained.

Description

technical field [0001] The invention relates to the technical field of iron and steel metallurgy, in particular to a method for smelting sulfur-containing steel. Background technique [0002] At present, in order to improve the quality of steel and reduce harmful gases in steel, more and more molten steel has been vacuum degassed. The production of sulfur-containing steel is carried out after sulfur alloying after vacuum treatment, and the sulfur content is controlled to the target range by feeding the sulfur iron wire after VD is broken. The main problem of this process is: feeding the sulfur iron wire after VD breaking, The recovery rate of sulfur is low and unstable, and the fluctuation range is large. It is necessary to re-feed the sulfur wire several times to make the sulfur content in the steel meet the target requirements. Due to the low melting point of the sulfur iron powder, the molten steel is violently boiled, resulting in secondary oxidation of the molten steel ...

AI Technical Summary

Problems solved by technology

The production of sulfur-containing steel is carried out after sulfur alloying after vacuum treatment, and the sulfur content is controlled to the target range by feeding the sulfur iron wire after VD is broken. The main problem of this process is: feeding the sulfur iron wire after VD breaking, The recovery rate of sulfur is low and unstable, and the fluctuation range is large. It is necessary to re-feed the sulfur wire several times to make the sulfur content in the steel meet the target requirements. Due to the low melting point of the sulfur iron powder, the molten steel is violently boiled, resulting in secondary oxidation of the molten steel and The molten steel absorbs a large amount of air, causing secondary pollution to the pure molten steel; after the sulfur wire is fed, the time for loading the steel is short, and the sulfur-containing inclusions cannot fully float out of the molten steel, and the pourability of the molten steel is poor, resulting in the nozzle of the continuous casting machine. Blockage, when the nozzle blockage is serious, it will cause unplanned shutdown of the continuous casting machine, which will seriously affect the stability of production and increase the cost of smelting; Large fluctuations, unable to guarantee the stability of the sulfur content in the finished continuous casting slab, which poses a potential threat to the quality of the continuous casting slab