High Temperature Oxidation Behavior of High Nitrogen 9%Cr Steels

摘要

High temperature oxidation behavior of high nitrogen steel with about 0.3 mass% of nitrogen has been investigated comparing with nitrogen-free steels and ASME grade 91. High temperature oxidation tests were carried out in air over the temperature range 750 to 850°C for 300 h at maximum. Weight gain was measured and oxide scales were observed using an optical microscope and analyzed with an electron probe X-ray microanalyzer. It was found that the oxidation resistance of the high nitrogen steel is superior to that of nitrogen-free steels and ASME grade 91. Furthermore, Cr concentration in the oxide scale of the high nitrogen steel was higher than that in other steels. These results indicate high nitrogen promotes the formation of the oxide scale with high concentration of Cr inhibiting oxidation from proceeding in the high nitrogen steel.