Research on Behavior of Inclusions before and after Calcium Treatment in Non-oriented Silicon Steel

Behavior of inclusions before and after calcium treatment in non-oriented silicon steel was researched by investigating changes of compositions,types,shapes and sizes of inclusions before and after calcium treatment,for the purpose of providing theoretical guidance for calcium treatment of non-oriented silicon steel in actual situation.Results indicated that Al₂O₃ and Al₂O₃-MgO were main types of inclusions before calcium treatment,sometimes AlN maybe precipitate in the outer of inclusions.Al₂O₃-MgOCaS-CaO system inclusions with a small amount of SiO₂ or AlN were dominant after calcium treatment.The shapes of inclusions changed from polygon or irregular before calcium treatment into spherical or near spherical,furthermore,the sizes of inclusions constantly increased.Furthermore,ratio of inclusions including calcium sharply increased from 10 percent before calcium treatment to 74.5 percent after calcium treatment.Meanwhile,the ratio of inclusions including calcium decreased when calcium treatment time extended,which suggested that calcium treatment was beneficial to aggregation,grow-up,floating and removal of inclusions.