High-Temperature Oxidation Resistance of Austenitic Stainless Steels

The oxidation kinetic curves of four kinds of austenitic stainless steel at 700°C was measured by weighting method. It is showed that the oxidation curves of those austenitic stainless steels follow the parabolic law. The mass gain of 800Al steel. is the least of all. The surfacemorphology and structure of the oxide scale were studied by scanning electron microscopy and X-ray diffraction methods. It is found that adense oxide scale formed at 700°C in all four austenitic stainless steels. In austenitic stainless steel with high Mn content, scales are mainly composed of Mn2O3 and the spinel MnFe2O4. Scales of austenitic stainless steel with high Cr content but without element Al are composed by Cr2O3 and the small amount of spinel FeCr2O4 . Scales of austenitic stainless steel with element Al and Cr are composed of (Fe0.6Cr0.4)2O3 and Al oxide, showing the excellent oxidation resistance property.