Influence of test parameters on the cyclic oxidation behavior of AISI 310 and a new Fe-5.9Si-3.9Cr-4.5Ni-0.8C (wt.%) alloy

High-temperature cyclic oxidation is governed by various cycle parameters (maximum temperature, cooling and heating rates, exposure time at high temperature) and atmosphere (composition, temperature, and pressure), complicating the evaluation of the effect of each parameter by itself. This study used a factorial design to evaluate three influential parameters in cyclic oxidation: alloy composition, upper dwell time (UDT), and surface finish. The method requires fewer experiments than ones previously used and can identify interactions between parameter effects. Two alloys, a ferritic Fe-5.9Si-3.9Cr-4.5Ni-0.8C (FeSiCr) alloy and conventional austenitic stainless steel AISI 310 were exposed to air at 950 °C for 100 h. Two different surface finishes (#220 and #600 SiC sandpaper) and two UDTs (30 and 60 minutes) were used. Mass variation data from eight different exposure times and metal/oxide interface roughness were analyzed. The FeSiCr alloy oxide layer was also characterized to complement the statistical analysis results. It was observed that different test stages were governed by different parameters. The surface finish was relevant at the beginning of the test, whereas UDT was relevant at the end. Interactions were irrelevant thorough the test. FeSiCr presented a promising behavior, with similar mass variation and higher oxide spallation resistance than AISI 310. (author)