Abstract:

Combining scanning electron microscopy and large sample electrolysis, the composition and source of inclusions in the surface linear defects of W800 grade non-oriented electrical steel in the CSP process were studied. SPSS software was used to regress and analyze the main factors which affected the surface linear defects in the steelmaking process. Research shows that the content of large inclusions in the steady state casting process is 5.39 mg/10 kg. The large inclusions which cause linear defects on the surface of non-oriented electrical steel are mainly deoxidized products, magnesia-aluminum spinel and ladle top slag, and the main types are Al₂O₃, MgO-Al₂O₃, CaO-Al₂O₃-MgO and CaO-Al₂O₃-SiO₂. The cleanliness of steel in the unsteady casting process reduces significantly, and the proportion of linear defects on the surface of the hot-rolled sheet increases. The main factors affecting the surface linear defects are w(CaO)/w(Al₂O₃) at the top slag of RH exit, oxygen level at the end of RH deoxidation and minimum tonnage of tundish in continuous casting process.

Key words: CSP process, non-oriented electrical steel, linear defects, regression analysis