Investigation of the possibility of introducing yttrium oxide by vacuum induction melting to produce nickel-free stainless steel

Abstract

The possibility of smelting an oxide-dispersed strengthening steel alloy using five different approaches involving the introduction of finely dispersed Y2O3 particles into liquid Fe-13Cr steel alloy under vacuum conditions has been investigated. To achieve the objective, five series of experiments were carried out, each differing in the conditions and process of the experiments. Two series of melting, were performed to evaluate the possibility of mechanical introduction of yttrium oxide into the melt under different conditions of introduction. The subsequent three series, were carried out to study the possibility of oxidation of metallic yttrium in the melt with the formation of yttrium oxide particles. In these experiments such parameters as duration of melt holding time and residual pressure in the furnace chamber were varied. When the obtained ingots were analysed by X-ray fluorescence (XRF), inductively coupled plasma atomic emission spectroscopy (ICP-AES) and energy dispersive X-ray spectroscopy (EDS), it was found that a significant amount of yttrium oxide was not successfully incorporated into the steel volume. A method using oxidation of metallic yttrium in the melt by reduction of added iron oxide was found to be the most promising.