Influence of crucible material on inclusions in 95Cr saw-wire steel deoxidized by Si-Mn

Abstract

To investigate the interaction mechanism between 95Cr saw-wire steel and different refractories, we conducted laboratory experiments at 1873 K. Five crucible materials (SiO₂, Al₂O₃, MgO·Al₂O₃, MgO, and MgO-CaO) were used. The results indicate that SiO₂, Al₂O₃, and MgO·Al₂O₃ are not suitable for smelting low-oxygen, low-[Al]_s 95Cr saw-wire steel, mainly because they react with the elements in the molten steel and pollute the steel samples. By contrast, MgO-CaO is an ideal choice to produce 95Cr saw-wire steel. It offers three advantages: (i) It does not decompose by itself at the steelmaking temperature of 1873 K because it exhibits good thermal stability; (ii) [C], [Si], and [Mn] in molten steel cannot react with it to increase the [O] content; and (iii) it not only desulfurizes and dephosphorizes but also removes Al₂O₃ inclusions from the steel simultaneously. As a result, the contents of the main elements ([C], [Si], [Mn], [Cr], N, T.O (total oxygen)) in the steel are not affected and the content of impurity elements ([Al]_s, P, and S) can be perfectly controlled within the target range. Furthermore, the number and size of inclusions in the steel samples decrease sharply when the MgO-CaO crucible is used.

Keywords

nonmetallic inclusions / 95Cr saw-wire steel / crucible material / MgO-CaO refractory

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