生产20CrMnTiH钢的最佳CaO-Al2O3渣系成分

 研究了某厂冶炼20CrMnTiH钢所用精炼渣的成分变化对钢液中w(T［O］)与夹杂物成分的影响。基于Factsage软件探讨了精炼渣成分变化对钢液中w(T［O］)的影响机制，指出精炼渣碱度R、w(CaO)/w(Al2O3)以及MI指数是通过改变渣中的Al2O3活度与CaO活度，提高精炼渣的“Al2O3”容量，以达到降低w(T［O］)的目的，并在此基础上提出了适合冶炼20CrMnTiH钢的精炼渣系成分(质量分数)：CaO 50%~55%，Al2O3 30%~35%，SiO2 6%~8%，MgO 5%~8%，其他不超过3%。通过工业试验发现，使用此渣系后铸坯中的w(T［O］)降至10×10-6。

Best Composition of CaO-Al2O3 Slag System for Refining of 20CrMnTiH Steel

The effect of the refining slag composition changing on total oxygen content and inclusions was investigated. The mutual influences between slag and molten steel were studied by factsage thermodynamic calculation software. The results show that the effects of slag indexes are mainly attributed to the changes of activities of CaO and Al2O3. The higher “Al2O3 capacity” induced by the changes of activities of CaO and Al2O3 in slag is helpful to decrease the T.O content. Meanwhile, the proper refining slag content for smelting 20CrMnTiH is proposed on this basis, which is CaO 50%-55%, Al2O3 30%-35%, SiO2 6%-8%, MgO 5%-8%, others≤3%. Through industrial test using this refining slag, the result shows that the total oxygen in slab is reduced to 10×10-6.