Smelting method of medium-high-carbon sulfur-lead complex system free-cutting structural steel

Abstract

The invention discloses a smelting method of medium-high-carbon sulfur-lead complex system free-cutting structural steel. The smelting method comprises the processes of primary smelting, LF refining and vacuum degassing refining, wherein the process of primary smelting involves an electric furnace or a converter, and during tapping, sulphur or ferrous sulfide blocks are used according to the requirements for the original S content in steel and the components of steel balls and the desulfurization rate of an initial slag system during special steel tapping to achieve resulfurization; lime and high-purity quartz sand are adopted for preparing components of the main slag system, a deoxidizing agent and alloy containing C, Si, Al and Mn are taken as deoxidation alloying materials, and harmfuloccluded foreign substances are well controlled. By means of the smelting method, consideration to the good gas removal effect and good control over lead content can be guaranteed, and the situation that the gas content rises again to a great extent due to leading operation after vacuumizing is avoided; and meanwhile, through the combination of different vacuum modes and leading modes, a process dedusting system can be effectively utilized to collect lead vapor, the environment is prevented from being affected, and a great effect is achieved.

Description

technical field [0001] The invention relates to a method for smelting free-cutting steel, in particular to a method for smelting medium-high carbon sulfur-lead composite system free-cutting structural steel, belonging to the technical field of metallurgy. Background technique [0002] At present, there are many smelting and production processes for "sulfur free-cutting steel" in the domestic iron and steel industry, but there are very few smelting and production processes for "sulfur-lead composite free-cutting steel", and none of them can produce high-quality medium-high carbon lead-containing free-cutting structural steel. production. The existing problems are: (1) Vacuum degassing treatment and effective control of sulfur content cannot be taken into account. (2) The uniformity of lead and the control of gas content in steel cannot be taken into account. (3) It is impossible (even lacking this technology) to control the poor surface of the slab caused by the lead and su...

AI Technical Summary

Problems solved by technology

[0002] At present, there are many smelting and production processes for "sulfur free-cutting steel" in the domestic iron and steel industry, but there are very few smelting and production processes for "sulfur-lead composite free-cutting steel", and none of them can produce high-quality medium-high carbon lead-containing free-cutting structural steel. production

The existing problems are: (1) It cannot take into account the effective control of vacuum degassing treatment and sulfur content

(2) The uniformity of lead and the control of gas content in steel cannot be taken into account

(3) It is impossible (or even lacks this technology) to control the poor surface of the slab caused by the lead and sulfur in the steel, resulting in the need for surface grinding of the slab before rolling, which increases the cost