易切削钢方坯凹陷原因分析及控制

Control and analysis of causes of indentations on billets of free cutting steel

对1215MS牌号易切削钢坯表面凹陷缺陷,采用抛丸、酸洗、金相、电子探针和能谱仪检测分析凹陷的特征,结合生产实践,研究分析凹陷产生原因及影响因素。试验研究表明,结晶器采用高振频、低振幅的正弦振动方式,降低结晶器冷却强度,提高二次冷却的均匀性,抑制坯壳过早收缩,优化保护渣性能,降低渣的黏度,提高浸入式水口对中精度,能够有效控制1215MS钢坯凹陷发生。

For the surface indentations on billet of the 1215MS free-cutting steel,the characteristics of the indentation were detected by shot blasting,pickling,metallographic analysis,electron probe and energy spectrometer. Combined with the production practice,the causes and influence factors of the indentation were studied. The experimental research shows that the indentation can be improved effectively and avoided by adopting sinusoidal vibration with high frequency and low amplitude for the mold,reducing the mold cooling rate,restraining constriction of billet shell early,optimizing the properties of mold lubricant,reducing the viscosity of slag,increasing the accuracy of SEN,and promoting the homogeneity of secondary cooling.