The Oxidation And Creep Behaviors Of P92 Steel In Steam At 600℃

The oxidation and creep behaviors of P92 steel in steam at 600℃were investigated by three point bending creep test method with small specimen. The machince was desigened for the creep test with small specimen, more steady and higher precision in different environment. Creep curves were measured from the sample under different forces in air and steam at 600℃. Then steady creep rate vs. force in air was used to evaluate the creep behavior based on Norton parameters B and n. In short time (200 h), slight deformation in oxidation was observed due to the protection of oxidation and thus improved the creep property. The thickness of oxidation under 250 N at 600℃was fitted to extract the steam oxidation rule. The microstructure surface morphologies were observed by SEM. A lot of holes were found as oxidation channels for exchange of metal ion and oxygen. The oxidation at the tensioned side was thicker than the compressed surface. The oxidation scale consisted of four distinctive layers including Fe3O4 as outer layer, CrFe2O4 as inner layer and two narrow transition layers. And the steam oxidation process mechanism were investigated. The theoretical formula was established for oxidation and creep model in order to predict the creep rate of oxidation. The matrtial parameters were fitted in terms of test data.