A comparative study of high temperature oxidation behaviour in AISI 304 and AISI 439 stainless steels was performed between 850 and 950 °C, in oxygen and Ar-H2–H2O (100 vpm H2) atmospheres.
(1) Concerning the effect of the atmosphere on oxidation behaviour of each steel, our results show that: The oxidation resistance of the AISI 439 does not depend on the atmosphere. On the other hand, the AISI 304 steel has the same oxidation behaviour in both atmospheres, at 850 °C, but, at higher temperatures, its oxidation rate dramatically increases in oxygen atmosphere, in comparison to that observed in Ar-H2-H2O atmosphere.
(2) Concerning the performance of the steels under oxidation, our results show that: The AISI 439 steel has higher oxidation resistance than the AISI 304, in oxidizing atmosphere, for temperatures above 850 °C, while the AISI 304 steel has higher oxidation resistance than the AISI 439, in low pO2 atmosphere, in all the temperature range investigated.
(3) In most cases, a Cr2O3 protective scale was formed, whose growth kinetics follows a parabolic law. The exception was for the AISI 304 steel, at 950 °C, in oxygen atmosphere, which forms an iron oxide external scale, non-adherent, which results in a higher oxidation rate.