热轧钢板表面斑点缺陷分析

Analysis on Spot Defects on Surface of Hot-Rolled Steel Sheet

利用扫描电镜、光学显微镜等检测手段,对热轧钢板表面斑点缺陷进行了检验,分析了该缺陷的特征及产生原因。结果表明,热轧钢板表面斑点缺陷宏观特征为密集分布的近似圆形亮点,微观特征为异常粗大铁素体晶粒;层流冷却水不稳定过渡沸腾是导致斑点缺陷产生的主要原因;温度、板形等条件对斑点缺陷的产生均有较大影响。

pot defects on the surface of a hot-rolled steel sheet are checked by the scanning electron microscope and optical microscope, and the features of the defect and causes leading to the defect are analyzed. The analytical results show that features of macrostructure of spot defects on the surface of the hot-rolled steel sheet are similar like luminous points that are densely distributed around and those of microstructures are ferrite grains that are abnormally coarsened. The excessive boiling of the laminar cooling water due to its unstabitily is the main cause leading to spot defects while some other factors such as temperature and profile also have major influences on forming spot defects on the surface of the sheet.