热轧带钢残余应力相关板形缺陷机理分析及攻关措施

对残余应力相关板形缺陷归纳统计,按产生机理划分为瓢曲与翘曲两大类问题,侧弯与C翘分别是瓢曲和翘曲典型代表缺陷。侧弯与浪形存在相互对应关系,分析显性浪形、隐性浪形控制现状,发现精轧存在人工修改目标凸度设定值现象;建立平整机三维有限元模型,对比分析不同凸度带钢平整后横向应力分布情况,采用“小凸度+空过平整”措施,侧弯平均值从15.2降低至4.97 mm。因下支撑辊传动,带钢变形区存在搓轧区导致带钢上下表面应力差,导致C翘缺陷产生,这种现象通过动态显性有限元分析进一步得到验证,对比分析工艺参数,开展试验设计(DOE),通过工艺参数优化,C翘平均值从27.6降低至10.5 mm。

Mechanism analysis and research measures of residual stress-related plate shape defects in hot rolled strip

The residual stress-related plate shape defects are summarized and classified into two categories: buckling and warping according to the production mechanism, camber and C warp were typical representative defects of buckling and warping. It was found that the wave and the camber had a corresponding relationship. By analyzing the current situation of the visible wave shape and the invisible wave shape, it was found that there was a manual modification of the target crown setting value. A three-dimensional finite element model of the temper mill was established, and the stress distribution of the different strip crowns after rolling was compared and analyzed. By adopting the "small crown + non-rolling through the temper" measure, the average value of the camber defects was reduced from 15.2 to 4.97 mm. Due to the lower support roller transmission, the presence of the rolling zone in the strip deformation zone leaded to different stresses in the upper and lower surface of the strip, which caused the occurrence of C warp defects. This phenomenon was further verified by dynamic explicit finite element analysis. The process parameters were compared and analyzed, and the Design of Experiment (DOE) was carried out to further optimize the process parameters, and the mean value of the warping defect was reduced from 27.6 to 10.5 mm.