Rare earth steel production method for preventing continuous casting nozzle from nodulating

Abstract

The invention belongs to the technical field of steelmaking, and relates to a rare earth steel production method for preventing a continuous casting nozzle from nodulating. The method comprises the procedures of electric arc furnace primary smelting, eccentric bottom tapping and deoxidation, furnace rear slagging-off, LF furnace slagging refining, RH vacuum refining, soft blowing treatment and continuous casting. In the electric arc furnace primary smelting procedure, furnace charge is direct reduced iron and low-sulfur waste steel, and the sulfur content in terminal steel of an electric arc furnace is controlled to be smaller than or equal to 0.006%; the eccentric bottom tapping technology is adopted, the slag amount of tapping is reduced, meanwhile, deoxidation is conducted in the tapping process, and the oxygen content in the deoxidized steel is smaller than or equal to 0.001%; in the furnace rear slagging-off procedure, slag formed in the electric arc furnace tapping process is removed; pre-melted refining slag and lime are added into an LF refining furnace again for slagging refining, the sulfur content in steel is controlled to be smaller than or equal to 0.0020% after LF refining is completed, and the oxygen content in the steel is controlled to be smaller than or equal to 0.001% in the LF refining process; a rare earth alloy is added in the RH vacuum refining process, and the nitrogen content in steel in the process is controlled to be smaller than or equal to 0.003%; and in the continuous casting process, argon is adopted for whole-process sealing protection, and the continuous casting nitrogen increasing amount is controlled to be smaller than or equal to 0.0003%.

Description

technical field [0001] The invention belongs to the technical field of steelmaking, and in particular relates to a rare earth steel production method for preventing continuous casting nozzle nodules. Background technique [0002] The role of rare earth elements in steel mainly includes the following aspects: modifying inclusions in steel, refining grains, purifying molten steel, microalloying, strengthening grain boundaries, affecting phase transformation process and improving final state structure, etc. Rare earths can denature the inclusions in steel, and rare earths can change the shape of S (sulfur element) and O (oxygen element) inclusions, and improve the transverse plasticity of materials; rare earth compounds can provide effective non-spontaneous nucleation cores, or segregation It hinders the growth of crystal nuclei on the crystallization interface, which can refine the solidified structure of molten steel and improve its performance; rare earth elements can react ...

AI Technical Summary

Problems solved by technology

However, the slag of the converter is relatively serious, which has a great impact on the purity of molten steel. If the slag of the converter is not well controlled, it will have serious consequences for the rare earth alloying method proposed in this patent, which will affect the yield of rare earth elements. and steel purity