Features of Distribution of Nonmetallic Inclusions by Glow of Hot-Rolled Blank from Fe–Ni–Cr Alloy

Inclusions in steels and alloys reduce deformation resistance, as well as mechanical, corrosion and other properties. Studies of inclusions in Fe–Ni–Cr alloys are important because products made from these materials are used under significant loads and exposure to aggressive environments. Identification of inclusions using optical and electron microscopy methods showed that a large proportion of inclusions are small refractory oxides MgO⋅Al2O3 in a shell of CaO⋅6Al2O3 of steelmaking origin. The sulfide component is released on refractory oxides, which leads to the formation of crystallization oxysulfide inclusions, which consist of oxides CaO⋅6Al2O3 in a sulfide shell. The share of oxide and oxysulfide inclusions is 93% of other types of inclusions. It is shown that the distribution of inclusions over the cross-section of a hot-rolled billet has a hereditary nature with the preservation of the distribution of inclusions of the original ingot. At the same time, an increase in the content of oxysulfide inclusions corresponds to a decrease in the content of sulfide inclusions located along the grain boundaries.