20CrMo钢中大颗粒夹杂物来源的示踪研究

Study on Large Particle Inclusion Origin in the 20CrMo Steel by Tracer Method

采用Ba CO3示踪法标定20Cr Mo钢大颗粒夹杂物的来源。示踪标定方法包括(1)LF炉精炼初期加入示踪剂和(2)VD结束加入示踪剂两种。扫描电镜分析结果示出:示踪标定方法(1)LF炉精炼过程含Ba夹杂物逐渐向钢中转移,VD之后和棒材中夹杂物全部含有Ba元素;示踪标定方法(2)的软吹结束和棒材中检验未发现含Ba夹杂物。以上说明20Cr Mo钢中夹杂物的来源为LF精炼和VD处理钢包顶渣卷入钢水中的细小渣滴,再与钢水发生化学反应,未及时上浮去除,形成了最终的大颗粒夹杂物形态。

BaCO_3 tracer method calibrate generation mechanism of large inclusions for 20 Cr Mo steel was adopted. There were two kinds of tracer method,including tracer added（1） in initial of LF refining profess and（2） after VD treatment. SEM results of tracer（1） analysis show that containing barium inclusions transfer to liquid steel during LF refining process gradually,and inclusions all contain barium after VD treatment or in bar;Tracer（2） show that there was no barium inclusions after soft blowing or in bar andyzed by SEM. Generation mechanism of 20 Cr Mo steel inclusions was fine＂ slag drop＂,ladle slag mixed into liquid steel,during LF refining and VD treatment,which occurring chemical reaction with liquid steel,and floating removal no timely. The large inclusions morphology was formed finally.