Composition change in oxide inclusions of stainless steel by heat treatment

Abstract

It is known that the oxide composition in stainless steel changes during heat treatment; however, the precise conditions to cause change are not clear. Therefore, the conditions necessary to change the oxide composition by heat treatment have been investigated using steels with different concentrations of Si, Mn, Ni and Cr. The MnO-SiO 2 type inclusions changed into MnO-Cr 2 O 3 type inclusions in steel containing 18%Cr and 8%Ni after heat treatment with a low silicon concentration. At high silicon content, the MnO-SiO 2 type inclusion was stable after heat treatment. The change in the composition of oxide inclusions owing to heat treatment depended on the concentrations of Cr in steel. The critical Si content, below which the oxide composition change was observed after the heat treatment, decreased with the decrease in Cr content. In steel containing 1%Cr, the oxide composition change was not observed.

Reaction Between MnO-SiO2-FeO Solid Oxide and Solid Steel Deoxidized by Si and Mn During Heat Treatment at 1473 K (1200 °C)

“…Shibata et al [1,2] investigated the solid-state reaction at the interface between Fe-Cr steel and MnO-SiO 2 oxide created by heat treatment at 1473 K (1200°C) using the diffusion couple method. It was shown that MnO-SiO 2 -type inclusions changed to MnO-Cr 2 O 3 -type inclusions in the case of low Si content in the steel.…”

Mechanism of Change in Chemical Composition of Oxide Inclusions in Fe–Cr Alloys Deoxidized with Mn and Si by Heat Treatment at 1473 K

“…Later, Kimura et al 6) reported the change in the chemical composition of the oxide inclusions of stainless steel without the hot rolling process. Shibata et al 7) also recently investigated the effect of Cr content in the Fe-Cr alloy deoxidized by Mn and Si on the change in the chemical composition of the © 2011 ISIJ oxide inclusions without the hot rolling process by heat treatment at 1 473 K for 60 min. The change in the chemical composition of the oxide inclusions from MnO-SiO2 to MnO-Cr2O3 has been observed above 1 mass% Cr with low Si concentrations by heat treatment.…”

Modification of the inclusions in austenitic stainless steel by adding tellurium and zirconium

“…2,3 And while the sulphur improves the machining, it also causes a decrease in the corrosion resistance 4 and a slight lowering of the toughness and a general decrease of the mechanical properties.…”