STUDY OF HIGH-TEMPERATURE OXIDATION OF MOLYBDENUM-CONTAINING STEELS

The oxidation kinetics of the steels EI981A (10Kh16N25M6AF), R6M5, and 25Kh3M3BTsA was studied at 700, 800, and 1000 degrees C. The catastro phic oxidation (CO) was observed only at 1000 degrees C and only for t he steels containing > 5% Mo. The stabilizing effect of tungsten on th e Laves phase due to the formation of isomorphous solid solution was e stablished. This effect does govern the oxidation rate of the steel, T he effect of W (5.8%) surpasses the effect of chromium (up to 16%) and nickel (25%) in the steels. The CO mechanism observed in the present work coincide with that studied earlier. The X-ray diffraction analysi s of the scale indicated that the main scale constituents are spinel a nd a rhombohedral phase.