400mm特厚板坯中心偏析控制的研究

Research on central segregation control of 400 mm ultra-thick slab

通过对板坯宽度方向1/4,1/2和3/4处的C、S化学成分对比分析和射钉试验结果分析,可知400 mm特厚板坯凝固末端为"W"型凝固方式。基于此分析,研究了板坯凝固末端"W"型凝固的形成原因和动态轻压下重要参数Fs对中心偏析控制的影响,得出结论:在铸机二级中利用板坯宽度方向1/4处凝固固相率FS1代替板坯中心凝固固相率Fs实施轻压下是必要的,优化后铸坯中心偏析100%控制在C类1.5等级以下水平。

By comparing the chemical composition of C and S at 1/4,1/2 and 3/4 in the width direction of the slab and the results of the nail test,it is known that the solidified terminal of the 400 mm thick slab is a"W"solidification method.Based on this analysis,the formation cause of the"W"type solidification at the solidification terminal of the slab and the influence of the important parameter Fs of the dynamic soft reduction on the central segregation control are studied.The conclusion:when implementing soft reduction,it is necessary to use the solidification rate FS1 at 1/4 of the slab width to replace the solidification rate Fs in the slab center in level 2 system.After optimization,the center segregation of the slab is 100%controlled below the level of class C 1.5.