Effect of Humidity on High Temperature Oxidation of AISI 430 Stainless Steel

In order to investigate the high temperature oxidation behavior of AISI 430 stainless steel in atmosphere with humidity, the thermogravimetric analysis (TGA) has been conducted for different duration under air with variable absolute humidity (from 0% to 5%) at 800 °C and 900 °C. XRD has been used to determine residual stresses in each layer and in substrate. It has been found that the oxidation kinetics and residual stresses were affected by the water vapor. After oxidation, the oxide scale composed of an inner Chromia (Cr2O3) layer and an outer Mn1.5Cr1.5O4 spinel layer, while breakaway oxidation happened with the introduction of water vapor at 900 °C. The residual stresses in each of oxide layer are in compression and their levels varied with oxidation conditions.