Cyclic Oxidation of Fe-18Cr-21Mn-0.65N Austenitic Stainless Steel at 400-700 degrees C

摘要

Low nickel, nitrogen stabilized austenitic stainless steel has not been explored for its application in the temperature range of 400-700 degrees C. In the present investigation, nitrogen stabilized austenitic stainless steel (Fe-18Cr-21Mn-0.65 N) was oxidized cyclically from 400 to 700 degrees C up to 100 h. The effect of moist airflow on oxidation behavior from 400 to 700 degrees C was systematically studied gravimetrically and the oxidized surfaces were characterized using SEM(EDS) and XRD. Mn diffused from the matrix to surface and reacted with the oxygen associated with the passive chromia layer and formed non-protective Mn(2)O(3)and spinels of the oxides of Fe, Cr and Mn. At 700 degrees C, there was rapid vaporization of Cr and consequent reduction in weight gain in dynamic air as compared with that in static air. Precipitation of Cr2N of different morphology was established through TEM analysis.