Strain-rate damage model for Alloy 600 in primary water

The objective of this project is to provide the mechanical property data required for the development of a strain rate damage model for environmentally-assisted cracking of Alloy 600 tubing and to perform stress corrosion tests from which critical strain rate damage model parameters may be determined for Alloy 600 in primary water environments of PWR reactors. An evaluation phase was conducted on sixteen candidate program materials. Four heats of material were chosen. Tensile tests were performed at several strain rates at temperatures from 75 degree F. Stress relaxation tests were conducted at 600 degree F, 680 degree F and 750 degree F. This material property data can be combined with state-of-the-art finite element creep analyses to compute the strain rate damage function for stress corrosion cracking of Alloy 600 steam generator tubing as a function of geometry and loading. Critical strain rate damage parameters were determined for four heats of mill-annealed Alloy 600 tubing in primary water environments at 680 degree F by conducting slow strain rate stress corrosion tests as a function of strain rate. Effects of prior cold work and variations in primary water chemistry on these critical damage parameters are included. 10 refs., 41 figs., 16 tabs