为了研究LF-VD精炼工艺的脱硫效果，进行了9炉工业试验。通过对BOF-LF-VD和KR-BOF-LF-VD工艺冶炼中厚板钢中硫含量和炉渣成分的分析，研究了炉渣成分和工艺参数对脱硫的影响。结果表明，采用适宜的精炼渣系，通过LF-VD精炼能把钢中硫质量分数从转炉终点200×10-6左右脱至20×10-6以下；炉渣成分[w((MgO))]=4%～7%、[w((SiO2))]=7%～11%、[w((CaO))/[w((Al2O3))+w((SiO2))]]=1.62时，实现最高硫分配比接近500；VD精炼比LF精炼钢液搅拌强烈，能进一步脱硫。研究结果对优化中厚板炉外精炼脱硫工艺具有指导意义。

Nine heats of industrial trials were performed to investigate the desulfurization effectiveness of LF-VD refining process. The influence of slag composition and operating parameters on desulfurization was studied by analysis of sulfur content in steel and slag composition during production of plate steel by BOF-LF-VD and KR-BOF-LF-VD process. The results show that mass percent of sulfur in steel can be decreased to below 20×10-6 from 200×10-6 at the end of BOF refining with suitable refining slag. The highest sulfur distribution close to 500 can be achieved with [w((MgO))]=4%-7%、[w((SiO2))]=7%-11%，[w((CaO))/[w((Al2O3))+w((SiO2))]]=1.62 slag. VD refining can realize further desulfurization than LF refining because of better molten steel bath stirring.The present results are considered to be useful in optimizing secondary refining desulfurization process during plate steel production.