Abstract:Causes for surface indentations of 80 steel were analyzed and reasonable precautions were put forward. It is pointed out that changes of chemical composition, pouring temperature, casting speed, water, slag etc. can only weaken the surface indentations. Only by adjusting crystallizer water jacket, water gap, vibration level, can the surface indentation can be resolved completely. When the surface depression disappeared after the breakout, corner crack also disappeared and billet quality is guaranteed.