Quantitative evaluation of inclusion in deoxidation of Fe-10 mass pct Ni alloy with Si, Ti, Al, Zr, and Ce

The composition, size, number, and morphology of the inclusions in deoxidation of Fe-10 mass pet Ni alloys with 0.2 mass pct M (M = Si, Ti, Al, Zr, and Ce) containing mostly 60 to 130 mass ppm oxygen were studied as a function of holding time at 1873 K. It was found that the initial primary inclusions contained FeO and the FeO content decreased with an increase of deoxidation power and holding time. The mean spatial diameter of inclusions tends to increase with increasing holding time, but did not show the systematic trend with respect to the deoxidation power. The number of particle sections per unit area decreased with decreasing deoxidation power and increasing holding time. In the absence of stirring of melt, the growth rate of the mean spatial diameter of inclusions and the removal rate of particle sections per unit area decreased rapidly with increasing holding time and approached a constant after 10 minutes. The morphology of inclusions was found to be spherical, polyhedral (except Si), and irregular including cluster, and the mean spatial diameter of these inclusions increased with increasing holding time.