Abstract: The steelmaking process flowsheet of tested sulphur bearing non-quenching and tempering steel 36MnVNS4 (/% : 0. 36C, 0. 66Si, 1. 00Mn, 0. 010P, 0. 045S, 0.26V, 0. 011 ON) is hot metal + scrap- 70 t EBT EAF-LF-square billet casting-rolling. The effect of LF both slag series- 19. 82% Al₂0₃, ( CaO)/( SiO₂) = 2. 64 and 14. 63% Al₂O₃, (CaO)/( SiO₂) =2. 15 on oxygen content in liquid after soft argon blowing, S yield after feeding S wire, and compound and morphology of inclusions in steel has been studied. Results show that refining by high basicity white slag is available to decrease the oxygen content in steel, but it is unfavourable to stabilize the sulphur content in steel； decreasing the refining slag basicity ( CaO)/( SiO₂) from 2. 64 to 2. 15 is favourable to stabilized control the sulphur content in steel, and the yield of sulphur increases from 35% to 75% ； with both refining process the distribution, morphology and ingredient of inclusions in steel are basically the same. By calcium treatment in ladle the long strip MnS inclusions modify to spheroid compound inclusions.

Key words: Sulphur Bearing Non-Quenching and Tempering Steel, LF Refining, Basicity of Refining Slag, Deoxidation, Calcium Treatment, Sulphide

摘要： 试验的36MnVNS4含硫非调质钢（/%:0.36C,0.66Si,1.00Mn,0.010P,0.045S,0.26V,0.0110N）的冶炼工艺流程为铁水+废钢-70 t EBT EAF-LF-方坯连铸-轧制。研究了LF 19.82%Al2O3,（CaO）/（SiO₂）=2.64和14.63%Al2O3,（CaO）/（SiO₂）=2.15两种渣系精炼对软吹后钢中氧含量,喂S线后S的收得率以及钢中夹杂物成分和形貌的影响。结果表明,高碱度白渣精炼工艺有利于钢中氧含量的降低,但不利于钢中硫含量的稳定;精炼渣碱度（CaO）/（SiO₂）由2.64降低至2.15时,有利于钢中硫含量的稳定控制,硫的回收率由35%提高至75%;两种精炼工艺下钢中的夹杂物分布、形貌和组成基本相同。通过钢包钙处理,长条状MnS夹杂转变为球状复合夹杂。