连铸坯窄面凹陷缺陷产生原因分析及预防

Cause analysis and prevention of narrow-face concave defect of continuous casting billet

本文针对连铸坯窄面纵向凹陷缺陷,借助连铸坯缺陷宏观形貌分析、连铸坯低倍酸洗分析、金相组织分析和化学成分检测等手段,结合连铸坯生产工艺,分析了连铸坯窄面纵向凹陷缺陷产生原因。确定了连铸结晶器窄面冷却水量不合理造成的铸坯初生坯壳冷却不均,结晶器锥度过大对结晶器坯壳产生挤压是缺陷产生的主要原因。通过采取结晶器冷却水量优化、结晶器窄面锥度调整控制及保护渣性能优化等措施,有效提高了连铸板坯表面质量,杜绝了连铸坯窄面纵向凹陷缺陷发生。

In this paper,the causes of longitudinal concave defects on narrow surface of continuous casting billet were analyzed by means of macroscopic morphology analysis,low-power pickling analysis,metallographic analysis and chemical composition detection,and combined with the production technology of continuous casting billet.It is determined that the main cause of the defects is the uneven cooling of the primary billet shell caused by the unreasonable cooling water on the narrow side of the continuous casting mold,and the extrusion of the mold shell caused by the excessive taper.The surface quality of continuous casting slab was improved effectively by optimizing the cooling water quantity of mold,adjusting and controlling the taper of mold narrow surface and optimizing the performance of protective slag,and the longitudinal concave defect of narrow surface of continuous casting slab was prevented.