石钢GCr15轴承钢实践

GCr15 Bearing Steel Production at Shijiazhuang Iron and Steel Company

介绍了石钢采用60tBOF-LF-VD-CC流程生产GCr15轴承钢的工艺实践，重点研究了工艺过程中氧含量的控制，工艺过程为：以60t氧气转炉作为轴承钢初炼炉，终点高拉碳，控制下渣量≤50mm；采用高碱度（R≥3．5）CaO-Si02-Al2O3渣系进行钢包精炼处理，实现了较好的脱硫和脱氧效果，通过合理的吹氩制度去除了更多的夹杂物；VD处理时真空度控制在67Pa以下，保持真空时间为10～20min，VD处理结束后进行吹氩弱搅拌4min以上，去除了更多的夹杂物，保证了较低的氧含量；石钢施行全流程保护浇注，有效地防止了钢液的二次氧化。最终成材氧的质量分数平均为9．5×10^-6，最低达7×10^-6，达到了国内先进水平，实现了转炉冶炼GCr15轴承钢的高效、高质、低成本生产。

The GCr15 bearing steel is produced by 60 t BOF-LF-VD-CC route at Shijiazhuang Iron and Steel Company. The key points of the practice are：close oxygen content control on BOF by catching carbon practice, control of the slag carry over during BOF tapping, using CaO-SiOz-Al2O3 slag with high basicity（R≥3.5） for LF refining, removal ot deoxidization products by effective argon blowing,with further removal during VD process under a vacuum less than 67 Pa and for 10-20 minutes and a weak stirring for more than 4 minutes at the end of VD process,protective casting to prevent re-oxidation. The average oxygen content of the final products was 9.5× 10^-6 ,with the lowest of 7×10^-6. The production of GCr15 bearing steel at Shijiazhuang steel is on the domestic top level with such efficient, low cost route.