CREEP-RESISTANT, ALUMINA-FORMING AUSTENITIC STAINLESS STEELS FOR HIGHER TEMPERATURE USE IN POWER GENERATION SYSTEMS

摘要

A family of creep-resistant, alumina-forming austenitic (AFA) stainless steel alloys is under development at Oak Ridge National Laboratory for power generation applications in the 600-900 °C temperature range. These newly developed alloys exhibit a unique combination of excellent oxidation resistance via alumina scale formation and high-temperature creep strength, at comparable estimated raw material cost to commercially-available, advanced austenitic stainless steels. Recent efforts have found that Al and Nb levels significantly affect both oxidation and creep resistance of the AFA alloys at elevated temperatures. This paper overviews the alloy design strategy, and provides details about creep rupture-life studies at 750 - 850 ℃ and 70 -170 MPa and oxidation studies at 650 - 900 ℃ in air and in air with water vapor.