Abstract:In the present work, based on the systematic analysis of the factors contributed to the formation of slab cracks and inclusions under unsteady casting, the following modified casting pocesses were proposed: regular check on the cleaniness of tundish, protected casting of steel in the whole process, application of reducing cover agents of tundish and refractory materials and modification of the content of argon gas before casting. It was also proposed to take measures like the application of rapid casting speed lifting process, raise of superheat, optimization of inserting depth of submerged water nozzle. The combination of the effects of above processes was believed to reduce the occurrence of slab cracks and inclusions formed during unsteady casting. The productive practice has proved that taking the metioned processes effectively reduced the formation of slab cracks and inclusions under unsteady casting.