热轧平整带钢C翘机理分析及措施

Mechanism analysis of C warp defects of hot rolled strip in temper and its countermeasures

针对某厂S620GT热轧带钢平整后由下C翘改变为上C翘且其高度平均值达35.9mm的问题,对带钢C翘方式改变的机理进行了研究。分析认为,平整机下支撑辊传动造成带钢上下表面塑性变形区、前后滑区长度、前后滑值、中性点位置、摩擦力大小等变化,形成上下表面应力差,产生上C翘缺陷。通过开展有限元分析,明确了平整工作辊的配辊要求,即上工作辊辊径大于下工作辊辊径,辊径差在3mm以内;对比分析工艺参数,开展DOE试验,得到张力为影响热轧平整C翘的关键影响因子,轧制力、弯辊力为重要影响因子,并得到工艺参数的最优组合(张力220kN、轧制力4000kN、弯辊力-50kN)。平整工艺参数优化后,C翘缺陷高度平均值从35.9mm降至21.5mm,C翘缺陷控制的准确性与稳定性显著提高。

Aiming at the problem that the S620GT hot rolled strip changed from lower C warp to upper C warp and its average height reached 35.9mm after tempered,the change mechanism of the C warp mode of strip was studied.According to the analysis,the transmission of lower support roll driving caused changes in the plastic deformation zone on the upper and lower surfaces of the strip,the length of the front and rear sliding zones,the values of the front and rear slip,the position of the neutral point,and the amount of friction.Through carrying out finite element analysis,the roll matching requirements of the work rolls were clarified,and the roll diameter of the upper work roll was larger than the lower work roll diameter,and the roll diameter difference was within 3mm.The process parameters were compared and analyzed,and the design of experiment(DOE)test was carried out.It found out that tension was the key influencing factor on C warp,and rolling force and bending force were important influencing factors,and the optimal combination of process parameters(tension was 220kN,rolling force was 4000kN and bending force was-50kN)was obtained.After the optimization of the process parameters,the average height of C warp defect was reduced from 35.9mm to 21.5mm,and the accuracy and stability of C warp defect control were significantly improved.