Production method of converter smelted low-sulphur steel

Abstract

The invention relates to a production method of converter smelted low-sulphur steel. The production method comprises following steps: 1, molten iron KR stirring desulfurized lime powder, fluorite, and aluminium slag are mixed at a ratio of 10:1:1, wherein ladle slagging-off rate is controlled to be 90% or higher, and the S content of molten iron put into a furnace is controlled to be 0.003% or lower; 2, reactor washing after smelting of a former batch of non low sulphur steel and before smelting of a first batch of low-sulphur steel is carried out; 3, remaining slag and double slag operation is adopted in smelting of low-sulphur steel. According to the production method, reactor washing, remaining slag, and double slag treatment are combined for smelting in a converter, and reactor washing after smelting of a former batch of non low sulphur steel and before smelting of a first batch of low-sulphur steel is carried out, so that the sulphur introduced by remaining slag operation of the first batch of low-sulphur steel smelting is reduced, combination of remaining slag and double slag is beneficial for stable control of end point low sulphur content, converter end point sulphur content is controlled to be 0.005% or lower stably, the lowest sulphur content is 0.001%, technical guarantee is provided for development of low-sulphur novel steel; and at the same time, converter average smelting period is shortened by 4min or longer, converter operation efficiency is increased, and production capacity is increased.

Description

technical field [0001] The invention relates to the technical field of converter steelmaking, in particular to a production method for converter smelting low-sulfur steel. Background technique [0002] Smelting low-sulfur steel such as spring steel and cord steel, and refining to produce low-basicity slag system, it does not have desulfurization ability, and the sulfur content at the end of the converter is required to be controlled within 0.005%. The limited desulfurization capacity of the converter has become a key control link. Improper operation can easily lead to high-sulfur end-point modified steel or return to the furnace, which seriously affects production. At present, there are the following three modes of converter low-sulfur steel smelting. [0003] The first is the traditional method. The slag-retaining single-slag method is used for smelting in the same converter, and the desulfurization is carried out by means of multiple spot blowing at the end point. In t...

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Problems solved by technology

[0005] The third is to adopt double-link smelting in two converters, and the patent application number is CN201110448292.1 A low-sulfur steel production method is to adopt double-link smelting, carry out KR desulfurization treatment, and then slag the molten iron into the dephosphorization furnace. After the blowing, the semi-steel is mixed into the decarburization furnace. After the blowing, the molten steel S is ≤0.005%, and the sulfur content at the end point is controlled stably. However, the smelting cycle of the duplex method is long, and the average smelting cycle is longer than 60 minutes.

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