Abstract: The cracking formation factors of steel 430F rolled bar are analyzed by scanning electron microscope, ultra- high temperature laser confocal microscope, Gleeble-3500 and other experimental equipment combined with professional image processing software, the modification effect and mechanism of each element and the high temperature mechanical properties. The results show that the control of MnS morphology in 430F steel is poor, and the tiny crack caused by long strip MnS is the main reason for cracking. Fine MnS ・ Al₂O₃ • MgO is formed by magnesium modification and coarse MnS • (Te) is formed by tellurium modification to obviously improve the morphology of MnS, no cracks were found in the rolled products. The reduction of area of steel 430F changes obviously at high temperature, while the tensile strength changes significantly at low temperature, therefore, with increasing the starting rolling temperature of unmodified steel from 1180 °C to 1 200 ~ 1210 P and reducing the final rolling temperature from 1000 °C to 970 ~ 980 °C , the yield of products can increases from 85% to 95%.

摘要： 采用了扫描电镜、超高温激光共聚焦显微镜、Gleeble-3500等试验设备结合专业图像处理软件分析了430F钢轧材的开裂原因,各元素的改质效果及机理以及高温力学性能。结果表明,430F钢中MnS形态控制较差,长条状MnS所引起的细小裂纹是造成轧材开裂的主要原因;镁改质形成的细小MnS·Al₂O₃·MgO以及碲改质形成的粗大MnS·（Te）都使MnS的形貌得到了明显改善,未发现轧材裂纹;430F钢材的断面收缩率在高温段变化较为明显,而抗拉强度在低温段的变化较为显著,因此,将未改质钢开轧温度由1180 ℃提高至1200～1210℃,终轧温度由1 000 ℃降低至970～980 ℃,成材率由85%提高至95%。

关键词: 430F高硫易切削不锈钢, MnS改质, 轧制参数, 成材率