Abstract: The effect of RH desulphurization on inclusions in non oriented electrical steel through conventional process (continuous casting + hot rolling) and CSP process has been studied in this paper. When the amount of CaO-CaF2 desulfurizer is 1～4 kg/t， the RH desulfurization rate is about 25 %. The high oxidation of final slag and low MI value are one of the reasons for the desulfurization effect. The RH of CSP process is deoxidized by “aluminium followed by silicon”. The inclusions are mainly AlN, MnS, CaS and a small amount of calcium aluminate. At this time, the total amount of inclusions is mainly affected by nitrogen content, and the sulfur content is proportional to the density of sulfide inclusions. The RH of conventional process is deoxidized by “silicon followed by aluminium”. The content of oxide inclusions and AlN inclusions in the sample is equal, and the amount of Ca inclusions only accounts for about 12 % of the total inclusions. The corrosion of CaF2 from desulfurizer to refractories results in the amount of Mg inclusions in RH desulfurization sample twice as much as that in non-desulfurization.

Key words: RH desulphurization, inclusion, Non oriented electrical steel