Effect of nitrogen, carbon and tungsten on high-temperature oxidation of 12%Cr-15%Mn austenitic steel

Abstract

Oxidation behavior of Fe-12%Cr-15%Mn alloy has been studied in air at 773 to 973 K. The oxidation rate of the alloy was very low at 773 K, and the effect of each alloying element on the oxidation did not identified. At above 873 K, the oxidation behavior was affected by the ratio of N/C and tungsten content in the alloy; the increase of N/C and tungsten content increased oxidation resistance of the alloy. Results of EPMA showed that thin Fe-Cr nitride layer was formed adjacent to the alloy surface when the ratio of N/C was proper, which was useful to prevent the oxidation of alloy. It also showed that homogeneous mono layer oxide was formed on the W-containing alloy, whereas four layer oxide was formed on the W-free alloy. Beneficial effect of tungsten may be related to this homogenization action. Small addition of vanadium and titanium was also effective to improve the oxidation resistance of the alloy. It is confirmed that the oxide formed on the alloy with good oxidation resistance was mainly composed of (Mn, Cr)2O3.