The Initiation of Long-Term Creep Rupture Tests on the First Alloy 709 Commercial Heat

A systematic creep tests were conducted as part of a multi-lab effort to identify the material conditions for Alloy 709 Code Case Project. Nine candidate material conditions were studied with three melt conditions each with three S/A temperatures 1050, 1100 and 1150°C. The three melt conditions included AOD, ESR and ESR + Homogenization. The screening creep rupture tests were conducted under 600°C, 330MPa. AOD 1100 and ESR 1100 have been identified to be the top two material conditions for the Code Case project after a comprehensive evaluation. Long-term creep tests were initiated on AOD 1100 at the ORNL. The six creep tests were started at temperatures from 550 to 800°C, stresses from 38 to 309 MPa to target rupture time 60,000 hours. The loading strains agreed with those obtained from tensile tests at the corresponding temperatures.