凝固末端电磁搅拌对60Si2CrVAT连铸方坯凝固组织的影响

Effects of final electromagnetic stirring on solidification structure of 60Si2CrVAT spring steel billet

对M-EMS和M+F-EMS电磁搅拌作用下60Si2CrVAT弹簧钢铸坯的凝固组织进行了对比分析,从低倍组织、微观组织、碳偏析以及铸坯缺陷等方面入手分析,讨论了凝固末端电磁搅拌对铸坯凝固组织的影响。结果表明,凝固末端电磁搅拌可以显著改善60Si2CrVAT弹簧钢铸坯凝固组织,提高铸坯凝固组织的致密度,降低铸坯中心疏松和缩孔,而二次枝晶臂间距得到明显改善,中心等轴晶率明显提高,晶粒得到细化,从而显著地改善了铸坯的质量。

The effect of final electromagnetic stirring on solidification structure of high strength spring （HSS） steel 60Si2CrVAT continuous casting billet was studied. Analysis of the solidification structure is based on the macrostructure, the microstructure, the carbon segregation and the defects of the 60Si2CrVAT billet with M - EMS compared to that with M ＋ F - EMS. It is found that the solidification structure is modified by F - EMS, the tightness of the billet and the ratio of the equiaxed structure is considerably increased, the inner porosity and the shrinkage is remarkably reduced, the ratio of central carbon segregation decreases sharply, the secondary dendritic arm spacing is improved, the ratio of central equiaxed grain increases obviously, thus fine grain acquires. Therefore, the quality of the billet is modified by the F- EMS.