结晶器电磁搅拌对轴承钢大方坯碳偏析的影响

Influence of Mold Electromagnetic Stirring on Carbon Segregationon Continuously Cast Blooms of Bearing Steel

针对南钢大方坯连铸机轴承钢连铸电磁搅拌冶金效果不明显的问题,开展了优化轴承钢连铸结晶器电磁搅拌工艺参数的试验,对不同电磁搅拌参数及搅拌方式下铸坯和轧材碳偏析进行了研究。结果表明:大方坯心部和边部均为负偏析,1/4处为正偏析,320 mm×480 mm大方坯碳偏析指数基本在0.87～1.05,轧材碳偏析指数基本在0.94～1.03;正反交替的电磁搅拌有利于降低碳偏析,电磁搅拌的电流参数较大时,心部的负偏析较严重,随着搅拌电流的增大,产生的白亮带向铸坯中心移动并且白亮带宽度增大;轴承钢铸坯中的碳偏析会遗传到轧材上。

As metallurgical targets of mold electromagnetic stirring（M-EMS） in continuous casting of bloom for bearing steel were not fully achieved in Nanjing steel,experiments for optimizing process parameters of M-EMS were carried out.Carbon segregation of cast bloom and rolled products at different electromagnetic stirring parameters and stirring patterns was studied.The results show that there is negative segregation in the core and edge of bloom,and positive segregation in the 1/4x bloom,with the carbon segregation index of 320 mm×480 mm bloom at 0.87～1.05;the carbon segregation index of rolled metal is at 0.94～1.03.Positively and negatively alternating electromagnetic stirring is helpful to reduce the carbon segregation.When electromagnetic stirring current is relatively strong,negative segregation is severer in the core,and with the increase of the stirring electric current,the white zone moves to the bloom center and its width increases.The carbon segregation hands down from cast bloom to its rolled products.