M-EMS对45钢矩形坯铸态组织和溶质分布均匀性的影响
Effect of M-EMS on the as-cast structure and solute distribution homogeneity of 45 steel rectangular blooms
陈亮 1汤群伟 2王璞 1陈刚 2扈凯 2李伟涛 2张家泉1
作者信息
- 1. 北京科技大学冶金与生态工程学院,北京 100083
- 2. 潍坊特钢集团有限公司技术中心,山东潍坊 262400
- 折叠
摘要
以某钢厂断面尺寸200 mm× 240 mm的45钢连铸矩形坯生产为例,通过工业试验探究了 M-EMS电流强度对铸坯铸态组织和溶质分布均匀性的影响.结果表明,M-EMS会使铸坯柱状晶产生一定角度的偏转,中心的等轴晶率随M-EMS电流强度增大而增大;然而,相较于等轴晶区,柱状晶区的溶质分布均匀性更好;在较大的M-EMS电流强度下,由于钢液的冲刷作用,铸坯皮下产生了负偏析,其位置与枝晶偏转区域相对应,同时在铸坯内部CET位置处产生了较严重的正偏析,铸坯均质性恶化.适当降低M-EMS电流强度,尽管铸坯等轴晶区面积减小,但其全断面的成分均匀性得到明显提高,其中,等轴晶区的碳极差和标准差均比强搅拌工况下降低一半以上,有效提升了铸坯全断面的均质性.
Abstract
The production of 45 steel continuous casting rectangular bloom with a cross-section of 200 mm×240 mm in a steel plant is taken as an example,and the effects of M-EMS current intensity on the microstructure and solute distribution uniformity of the billet were investigated by industrial experiments.The results show that M-EMS can produce a certain angle deflection of columnar crystals in the bloom castings,and the equiaxed grain ratio increases with the enhancing M-EMS current intensity.It is noted,however,that the solute distribution uniformity in the co-lumnar crystal region is much better as compared to in the equiaxed crystal region.Additionally,a under skin nega-tive segregation band occurs frequently while with the conventional high M-EMS current intensity,which,corre-sponding to the dendritic deflection area as well,should be produced by the EMS induced liquid flow scouring effect of molten steel.At the same time,severe positive segregation is often observed at the CET position inside the strand,which deteriorates the homogeneity of the strand remarkably.By appropriately reducing the M-EMS current intensity,the composition uniformity of the bloom entire cross-section is significantly improved,although the equi-axed crystal area of the strand decreases.Accordingly,the carbon extreme range and standard deviation of the equi-axed crystal zone are reduced by more than half compared to those under strong stirring conditions,which is benefi-cial to an upgrading chemical homogeneity of the bloom castings.
关键词
矩形坯/M-EMS/铸态组织/均质性/枝晶偏转/柱状晶向等轴晶转变Key words
rectangular bloom/M-EMS/cast structure/homogeneity/columnar crystal deflection/CET引用本文复制引用
出版年
2024
NETL
NSTL
万方数据