Influence Of Oxidation Temperature On The Behaviour Of Sintered Ferritic Stainless Steels

摘要

The influence of oxidation temperature on two vacuum sintered ferritic stainless steels (AISI 409L Nb and AISI 434L) was studied. A complete microstructural study was carried out, evaluating also porosity. Oxidation tests were carried out at four different temperatures (700, 800, 900, and 1000℃), by means of isothermal experiments in air atmosphere for times up to 240 hours. Oxidation rate was evaluated by mass gain, and thermogravimetric tests were also carried out to analyse the rapid evolution of the attack during the first hours of exposure. The oxidized samples were studied by X-ray diffraction and SEM to determine the formed oxides and the influence of temperature and length of the exposure on the nature and structure of the scales. Results obtained made possible to see the important influence that the composition of the base metal and the porosity have in the oxidation behaviour at high temperatures of stainless steels manufactured by powder metallurgy.