Surface composition modification of high-carbon low-alloy steels oxidized at high temperature in air

Segregating alloys across a metal/oxide interface, which occurs when an iron alloy is heated at high temperature in air, was studied on five high-carbon low-alloy steels. The metallographic analyses showed differences between the oxidation kinetics, the decarburisation rates of the surfaces and the number of surface defects. The results of the AES analyses enabled the characterization of the concentration profiles of the alloy elements and to explain the differences observed between the oxidation kinetics, the decarburisation rates and the number of surface defects. All the concentration profiles are discussed and possible mechanisms are proposed in order to understand the profiles obtained.