65Mn高碳钢全流程夹杂物演变规律研究

Study on the Evolution of Inclusions in the Whole Process of 65Mn High Carbon Steel

为了研究65Mn工具钢全流程夹杂物的演变规律,通过全流程取样,分析了钢水的全氧和氮含量,铸坯的全氧含量可以控制在8×10^(-6)以内,成品氮含量控制在40×10^(-6)以内。利用自动扫描电镜对非金属夹杂物的组分、尺寸、数密度等变化特征进行了统计分析。全流程钢中非金属夹杂物的数密度整体呈降低趋势,从LF进站到出站,非金属夹杂物去除率为67%,铸坯中夹杂物数量密度为6.85个/mm^(2)。另外对各工序典型非金属夹杂物的成分制作了三元相图,分析了夹杂物的成分组成,以及全流程典型夹杂物的变化规律。

In order to study the evolution law of inclusions in the whole process of 65Mn tool steel,the total oxygen and nitrogen contents of molten steel were analyzed through the whole process sampling.The total oxygen content of the casting billet could be controlled to less than 8×10^(-6),and the nitrogen content of the finished product could be controlled to less than 40×10^(-6).The composition,size and number density of nonmetallic inclusions were analyzed by automatic scanning electron microscopy.The number density of non-metallic inclusions in the whole process showed a decreasing trend.From LF entry to exit,the removal rate of non-metallic inclusions was 67%,and the number density of inclusions in the casting billet was 6.85/mm^(2).In addition,the ternary phase diagram of the typical non-metallic inclusions in each process is made,the composition of inclusions is analyzed,and the change rule of typical inclusions in the whole process is analyzed.