高酸性环境用超低硫管线钢冶炼工艺研究

Study on Melting Process of Ultra-low Sulfur Steel for Linepipe Used under High-acid Service Condition

介绍了在铁水预处理难以达到深度脱硫的条件下,以脱硫热力学和动力学理论为基础,对铁水预处理、转炉炼钢、炉外精炼等工序的工艺进行优化。通过对铁水预处理采用复合脱硫剂、转炉冶炼控制硫含量以及出钢脱硫、LF精炼双渣深度脱硫等各工序脱硫进行合理分配,达到了弥补铁水预处理未能深度脱硫、减小LF精炼炉脱硫负荷的目的,冶炼出w(S)≤0.001%、Ca/S≥2.0、夹杂物均不大于0.5级的高酸性环境用超低硫管线钢。

Since it is hard to get deep desulfurization of hot metal just though pre-treatment process,related processes such as hot-metal pre-treatment,converter steel-making and off-furnace refining are optimized based on the theories of both thermodynamics and dynamics concerning desulfurization.Relevant technological measures are taken to properly and quantitatively control desulfurization level in process steps like hot metal pre-treatment with compound desulfurizer,sulfur content control in converter melting,desulfurizing in tapping and dual-slag deep desulfurizing in LF refining,so as to compensate the inefficiency of deep desulfurization during hot metal pre-treatment,and reduce the desulfurization intensity of the LF process.As a result,it is successful to produce the ultra-low sulfur steel for linepipe to be used under hi-acid service condition,which is in possession of w（S） ≤0.001%,Ca/S≥2.0 and inclusion ratings of A,B,C and D not higher than 0.5.