Effect of Heating Process on Precipitation Behavior of Inclusions in Continuous Casting Slab of Non-oriented Silicon Steel

By using scanning electron microscope(SEM) and inclusion analyzer, the precipitation behaviors of inclusions in non-oriented silicon steel 50WH470 continuous casting slab at different heating temperatures and holding time were investigated.Thermodynamic simulations of the inclusions were performed using the Thermo-Calc thermodynamic software.The results show that the cast slab mainly contains three types of inclusions: AlN, MnS and AlN-MnS.Between the heating temperatures ranging from 1050 to 1250 ℃ and holding time from 20 min to 180 min, the number of the inclusions increases first and then decreases with the temperature and holding time increasing.At 1110 ℃ holding for 40 min, the number of the inclusions reaches a maximum value of 242 mm^-2, and those with average size more than 1 μm accounts for 96.8%, which indicates that the inclusions extensively precipitate out and grow up.