基于热加工图法的热轧SAE4137棒材表面质量控制

 采用MMS-200热模拟试验机，在变形速率为0.1~10 s-1、变形温度为900~1 150 ℃以及最大变形量为70%的变形条件下对SAE4137钢进行等温热压缩试验。依据试验结果，基于动态材料模型以及Murthy失稳判定准则下，绘制出SAE4137钢在不同真应变下的热加工图，得到SAE4137钢在成形时的加工稳定区、失稳区以及推荐加工区间。通过微观组织分析进行验证，并结合南钢中间方坯（215 mm×235 mm）经过4道次精轧轧制[?]150 mm大棒材实际情况，预判SAE4137钢棒材生产过程中表面可能产生的缺陷及位置。

Surface Quality Control for Hot Rolling SAE4137 Bar Based on Processing Map Method

Isothermal compression experiments of SAE4137 steel were performed on an MMS-200 thermal-mechanical simulator at the strain rate ranging from 0.1 to 10 s-1, the deformation temperature ranging from 900 to 1 150 ℃ and the maximum height reduction of 70%. On the basis of the experimental results, dynamic material model and Murthy flow instability criterion, the processing maps for SAE4137 steel were constructed at the different true strains. The stable regions, flow instability regions and the recommended processing region were obtained for SAE4137 steel. Based on the analysis of microstructure and the practical condition of making intermediate billet (215 mm×235 mm) into [?]150 mm large bar through 4-pass finishing rolling in Nanjing Steel, the surface defect and its position of SAE4137 bar in production process were predicted.