EFFECT OF ALLOYING ELEMENTS ON THE 1ST ST EPS OF OXIDATION OF A LOW-ALLOY STEEL BETWEEN 600 AND 800-DEGREES-C

The behaviour of an extra-soft steel is studied during oxidation treat ment made in oxygen between 600 and 800-degrees-C for durations of les s than 10 min. The kinetics of oxide formation are measured by thermog ravimetry and by nuclear microanalysis. The segregation and internal o xidation of alloy elements were observed by scanning electron microsco py, energy dispersive X analysis, luminous discharge spectroscopy and transmission electron microscopy. A preferential concentration of thes e elements near the metal-oxide interface has thus been shown, which m akes it possible to explain the modification of the oxidation kinetics with respect to the one of unalloyed iron.