A method for smelting low-sulfur ultra-low-nitrogen molten steel in a converter

Abstract

The invention discloses a method for a converter to smelt low-sulfur and ultra-low nitrogen molten steel, and mainly aims at solving the technical problem that w[S] <= 0.0035 percent and w[N] >= 0.0012 percent in chemical components of converter tapping molten steel produced by smelting in the converter in the prior art are hard to implement. The technical solution of the invention is that the method for the converter to smelt the low-sulfur and ultra-low nitrogen molten steel comprises the following steps: adding scrap steel, and charging molten iron; performing early-stage converter smelting, intermediate-stage converter smelting and later-stage converter smelting; tapping immediately after converter smelting is ended; and deslagging. According to the method disclosed by the invention, by defining a ratio of a metal charge to a slag forming auxiliary material of the converter and sulfur content, and by controlling the early stage, the intermediate-stage and the later stage of converter smelting, tapping and deslagging, smelting of w[S] <= 0.0035 percent and w[N] >= 0.0012 percent in the chemical components of the converter tapping molten steel is realized. The method disclosed by the invention has a stable process; the smelting hit rate of the chemical components of the molten steel is high, and the production cost of the low-sulfur and ultra-low nitrogen molten steel is reduced.

Description

technical field [0001] The invention relates to a method for smelting molten steel in a converter, in particular to a method for smelting low-sulfur and ultra-low-nitrogen molten steel in a converter, and belongs to the technical field of converter steelmaking. Background technique [0002] At present, some high-quality steels have high requirements for the elements sulfur and nitrogen at the same time. For example, non-oriented electrical steel generally requires w[S]≤0.0040%, w[N]≤0.0020%. The traditional desulphurization method needs multiple combined process measures such as pre-desulfurization of molten iron, control of sulfur content in converter, use of ladle refining furnace (LF furnace, Ladle Furnace) for desulphurization, and vacuum circulation degassing method for powder spraying desulphurization to control sulfur content. For smelting steel types with w[S]≤0.0040%, the existing converter steelmaking process cannot meet the requirement of w[S]≤0.0040% in converte...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a method for smelting low-sulfur and ultra-low-nitrogen molten steel in a converter, which mainly solves the problem of w[S]≤0.0035% and w[N]≤0.0012 in the chemical composition of the converter tapping molten steel produced by converter smelting in the prior art. % Difficult to implement technical issues

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