汽车齿轮钢8620RH的洁净度

以抚顺特殊钢股份有限公司一炼钢厂的生产数据为实践依据，以改善汽车齿轮钢8620RH的夹杂物和氧质量分数两个洁净度指标为目的，使用扫描电镜分析冶炼过程中LF炉(钢包精炼炉)初期、LF炉末期、VD（真空脱气）处理前以及软吹后4个节点的钢液中夹杂物形貌和成分，明确钢中夹杂物的演变过程。通过降低电炉终点氧质量分数分析LF精炼炉渣成分，强化LF炉白渣精炼操作以及控制VD处理后的软吹效果等措施，达到汽车齿轮钢8620RH氧质量分数平均值为0.001 17%，B类夹杂物中B细不高于1.5级、B粗不高于0.5级的冶炼控制水平。

Cleanliness of automobile gear steel 8620RH

On the basis of actual production data in the first steelmaking plant of FuSteel， the objective is to improve cleanliness indexes，including the inclusion and oxygen mass fraction of automobile gear steel 8620RH. Morphology and composition of inclusion in liquid steel were analyzed at 4 periods of the steelmaking process，namely initial stages of LF，the End of LF，before VD treatment and after soft blowing by using SEM. And the evolution process of inclusion in liquid steel was definite. Through decreasing the end of oxygen mass fraction of UHP，analyzing the slag composition of LF，strengthening the white slag operation of LF and controlling the soft blowing effect after VD，for automobile gear steel 8620RH，the average oxygen mass fraction can reach to 0.001 17%，B thin series rating of inclusions is no more than 1.5 and B coarse series rating of inclusions is less than or equal to 0.5.