Deployment of Alumina Forming Austenitic (AFA) Stainless Steel

The purpose of the project was to accelerate the deployment and further the development of a new family of heat-resistant alloys developed at ORNL: alumina-forming austenitic (AFA) stainless steels. Initial laboratory scale evaluation indicated that AFA alloys possess exceptional high-temperature oxidation resistance while retaining creep properties similar to other advanced austenitic stainless steels. The AFA steels therefore represent a low-cost alternative to Ni-base alloys and a high performance alternative to conventional advanced austenitic steels. Deployment of AFA steels into turbine and other energy-related applications can lead to improved efficiencies by achieving higher operating temperatures and/or improved durability and component lifetime at costs comparable to currently used alloys. The development and scale up of optimized AFA alloy compositions in both wrought and cast forms, including generation of a database of thermo-physical, mechanical, welding/joining, and high-temperature corrosion properties was needed to enable consideration and adoption of these new materials in applications ranging from turbines, heat exchangers, and fuel cells to boilers and chemical/petrochemical processing. The project consisted of four primary tasks: commercial demonstrations, property database development, alloy development and optimization and evaluation of as-cast properties.