Smelting process for production of super-low sulphur steel

Abstract

A smelting process for the production of super-low sulphur steel belongs to the technical field of steelmaking, and adopts the process route of molten iron magnesium jetting desulfuration pretreatment-converter smelting-ladle dusting-LF Furnace refining-RH refining-continuous casting. The smelting process is characterized in that the molten iron pretreatment adopts magnesium particle jetting for desulfuration; the converter smelting adopts high-grade steel scrap and lime; during tapping, ferro-aluminum is used for strong deoxygenation and slag surface deoxygenation is conducted; the ladle dusting is used for controlling reasonable jetting speed and dust consumption; the LF Furnace refining is used for controlling the feeding quantity of high-alkalinity refining slag and the bottom jetting flow rate of a ladle; and after refining, the oxidizing property and the alkalinity of steel slag are guaranteed. The invention has the advantages that super-low sulphur steel making can be realized fast on the condition that the sulphur content at the end point of the converter cannot be controlled stably; the dusting desulfuration jetting of the ladle lasts for 10 to 15 min; the desulfuration during the LF Furnace refining lasts for 15 to 30 min; the content of sulphur in steel can be controlled within 0.0010 percent fast and stably; and the batch stable control of super-low sulphur steel can be realized.

Description

technical field [0001] The invention belongs to the technical field of steelmaking, and in particular relates to a method for producing ultra-low sulfur steel, especially realizing stable control of sulfur content in steel when smelting ultra-low sulfur steel. Background technique [0002] In addition to special steel types, sulfur is a harmful element in steel, which can cause hot embrittlement of steel, and can also adversely affect the mechanical properties of steel by forming sulfide inclusions. With the increasing demand for high-grade steel, the quality requirements for steel are becoming more and more stringent. During the smelting process, the sulfur content in the steel is required to be as low as possible, especially for pipelines, containers, etc. Steel grades require that the sulfur content be less than 0.0010%. Therefore, whether the stable control of ultra-low sulfur content in steel can be achieved becomes the key to the production of ultra-low sulfur steel. ...

AI Technical Summary

Problems solved by technology

[0005] According to the patent search related to the domestic ultra-low sulfur steel smelting control process, there are currently two methods for the ultra-low sulfur steel smelting control process: one is to use special desulfurization materials to desulfurize molten steel in the refining process, the biggest problem of this process One is that the control is unstable, and it is difficult to meet the needs of mass production; one is to use KR hot metal desulfurization pretreatment and follow-up supplementary desulfurization for ultra-low sulfur steel smelting. This method puts forward requirements for smelting equipment, and it is only for iron and steel enterprises with KR equipment. And the desulfurization of ultra-low carbon steel has certain limitations

[0006] Based on the above reasons, this patent proposes a new smelting process for the production of ultra-low sulfur steel: hot metal spray magnesium desulfurization pretreatment-converter-ladle powder spray-LF furnace refining-RH refining-continuous casting, realizing ultra-low sulfur steel batches According to the needs of production, this kind of process is used to smelt ultra-low sulfur steel, and no patent related to this process can be found after searching