含硫钢8620RH夹杂物控制技术工艺实践

Inclusions control technique in production of sulfur-bearing steel 8620RH

江苏沙钢集团淮钢特钢股份有限公司采用90 t顶吹转炉拉碳操作法,控制转炉终点C质量分数为0.07%～0.15%,出钢过程加入合金铝脱氧,采用CaO-Al_2O_3-SiO_2高碱度渣精炼,真空处理,连铸过热度控制在15～30℃,M＋F二段电磁搅拌,全过程吹氩保护浇铸,生产200 mm×200 mm 8620RH钢坯,并堆垛缓冷。实践证明：通过调整Ca/Al（不小于0.13）、控制成品Al含量、控制软吹时间等工艺措施,硫化物级别成功控制2.5级以内,且浇铸过程比较稳定,没有出现明显结瘤现象,验证了新工艺对改善硫化物夹杂有显著的效果。

The 200 mm×200 mm casting billet of steel 8620 RH is produced at Jiangsu Shagang Group Huaigang Special Steel Co Ltd by using 90 t BOF top blowing conwerter melting with carbon catch operation to control the converter end [C] 0.07%-0.15%,adding aluminium-iron in ladle during tapping for oxidation,using CaO-Al_2O_3-SiO_2 high alkalinity slag refining,vacuum processing,casting superheat control in 15-30 ℃,M＋F electromagnetic stirring,the whole process of argon protective casting and stacking slow cooling. Practice has proved that：by adjusting the Ca/Al（≥0.13）,control the finished product Al content,control soft-blowing time,sulfide levels within the successful control of 2.5,and the casting process is relatively stable,with no apparent nodulation phenomenon,verified new technology to improve the sulfide inclusions have a significant effect.