Heavy-rail steel sulfur content controlling method

Abstract

The invention provides a heavy-rail steel sulfur content controlling method. According to the invention, sulfur weight during a converter tapping process is controlled, LF furnace and VD furnace slagging manners are improved, and casting parameters of a casting machine are adjusted. With the measures, desulphurization speed in the processes are effectively controlled, such that heavy-rail steel sulfur weight is stably controlled in a range of 0.08-0.20%. Compared to existing technologies, with the method provided by the invention, large-amplitude desulphurization of the LF furnace and the VD furnace can be realized, and desulphurization during the processes can be effectively controlled. With traditional technologies, included sulfide caused by large-amplitude desulphurization can hardly be sufficiently discharged. With the method provided by the invention, the problem is solved, such that a defect of over-standard heavy-rail steel sulfide is avoided. With the method, a sulfur weight of a tundish finished product is improved from 0.0052% to 0.0124%. The proportion of S>0.008% is improved from 42.6% to 99.1%, such that the quality qualification rate of heavy-rail steel is substantially improved.

Description

technical field [0001] The invention belongs to the technical field of steelmaking technology, and in particular relates to a method for controlling the sulfur weight percentage content (referred to as weight) of heavy rail steel. Background technique [0002] Hydrogen is a harmful element in heavy rail steel, so controlling the weight of hydrogen is an important indicator of heavy rail steel. When the heavy rail steel contains a certain amount of sulfur, it will help solidify the hydrogen element and reduce the influence of hydrogen on the steel quality. For heavy rail steel, the sulfur weight is usually required to be controlled between 0.008-0.020%. However, since the production of heavy rail steel generally needs to go through processes such as converter smelting-LF furnace (ladle refining furnace) refining-VD furnace (vacuum refining furnace) refining treatment and casting machine casting, most of the sulfur weight is removed after these processes , it is difficult to...

AI Technical Summary

Problems solved by technology

However, since the production of heavy rail steel generally needs to go through processes such as converter smelting-LF furnace (ladle refining furnace) refining-VD furnace (vacuum refining furnace) refining treatment and casting machine casting, most of the sulfur weight is removed after these processes , it is difficult to stably ensure that the sulfur weight is controlled above 0.008%

If sulfur-containing alloys are added in the refining process, although the requirement of controlling the sulfur weight above 0.008% can be achieved, with the addition of sulfur-containing alloys, the sulfide inclusions will also increase significantly, so that the sulfide inclusions exceed the weight. Rail steel requirements, resulting in excessive sulfide defects, directly affect the product quality pass rate