短流程热轧带钢拉窄问题分析及改进

Analysis and improvement of narrowing of hot rolled strip in short process

针对唐钢FTSR短流程热轧产线带钢拉窄问题,根据拉窄发生的位置将其分类为带钢头部拉窄、带钢后半段拉窄和带钢尾部拉窄。对现场张力设定、张力反馈、头部穿带过程及轧机抛钢过程进行了分析,确定了造成带钢拉窄的原因,即带钢头部张力控制偏高,导致带钢头部拉窄;R2和F1之间使用无活套的张力控制,计算的张力并不能真实反映出中间辊道带钢的实际张力,导致带钢后半段拉窄;活套进入小套量控制的时序过早,目标角度较小,导致带钢尾部拉窄。为此,从无活套张力控制、精轧穿带速度因子、冲击补偿功能、张力设定、小套量控制时序及目标角度等方面提出了优化措施,解决了带钢拉窄问题。现场应用表明,基本杜绝了带钢尾部拉窄低于公差下限的情况,拉窄卷数从21卷/月降至10卷/月以下。

Aiming at the problem of strip narrowing in the FTSR short flow hot rolling line of Tangshan Iron and Steel Co.,Ltd.,according to the location of strip narrowing,it was classified into strip head narrowing,striplatter half narrowing and strip tail narrowing.Based on the analysis of tension setting,tension feedback,head threading process and rolling mill throwing process,the causes of strip narrowing were determined,i.e.,the high tension control of strip head leads to strip head narrowing;the tension control without looper was used between R2 and F1 mill,and the calculated tension could not truly reflect the actual tension of the strip in the middle roller table,which resulting in the narrowing of the latter half of the strip;the timing of looper entering small quantity control was too early,and the target angle was small,which leads to the narrowing of the strip tail narrowing.Therefore,the optimization measures were put forward from the aspects of tension control without looper,threading speed factor of finishing rolling,impact compensation function,tension setting,control sequence of small quantity of looper and target angle,so as to solve the problems of strip narrowing.The field application show that the situation of strip tail narrowing lower than the lower limit of tolerance is basically eliminated,and the number of narrowing strips is reduced from 21 coils per month to less than10 coils per month.