INCLUSION MODIFICATION WITH MG TREATMENT FOR 35CRNI3MOV STEEL

The effects of Mg on the inclusion characteristics of 35CrNi3MoV steel have been studied. The results show that Mg treatment reduces obvious ly the amount of inclusion in the steel. Magnesium and oxygen in liqui d steel form dispersed fine particles of MgO, to which other oxides or sulphides nucleated at heterogeneity and grown during solidification. In this way the inclusions are modified. The small spherical inclusio ns containing MgO have been observed in the Mg treated steel in contra st to the large angular inclusions with Al2O3 in the conventional stee l. Especially the elongated MnS inclusion is replaced by small MgS . M gO or MgS. MnS . MgO complex inclusion. The formation of inclusions ha ve been discussed.