改善T91钢洁净度的生产实践

Production Practice on Improving Cleanliness of T91

基于抚钢二炼钢厂的生产数据,以改善T91的洁净度为目的。使用扫描电镜分析轧材中B类非金属夹杂物的化学成分,确定了夹杂物成分为Al-Mg-Ca-O或Al-Ca-O,是由铝脱氧产物与钢包耐材和钢包顶渣反应后逐渐演变而来。通过优化VOD还原阶段的渣料配比,降低渣料用量,同时改进LF炉精炼炉渣成分,提高了钢包顶渣的夹杂物吸附能力。将VOD吹氧脱碳的目标碳含量由≤0.03%修改为0.06%~0.07%,以减少氧化铝夹杂物产生量。T91轧材的洁净度水平达到氧含量平均值为25.2×10^(-6),B类夹杂物B细不高于1.5级、B粗不高于1.0级的控制水平。

On the basis of actual production data in the second steelmaking plant of Fu Steel,the objective is to improve cleanliness of T91.The chemical composition of B inclusion,Al-Mg-Ca-O or Al-Ca-O,was analysized by using SEM,which gradual evolution from the reaction between aluminum deoxidation products and ladle refractory or slag.The inclusions adsorption capacity of ladle top slag was increased,through optimizing slag proportion of VOD reduction stage,reducing slag dosage,and improving composition of refining slag.The production of oxide inclusions were reduced,by changing aim carbon after blowing oxygen decarbonization of VOD from less than 0.03%to 0.06%~0.07%.The average oxygen content can reach to 25.2×10^-6),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 1.0 in bar.