Analysis of a UNS N08800 hydrogen unit preheat tube that failed in service. Based on chemical and metallographic analyses the failure was attributed to liquid metal embrittlement by zinc. The zinc source is thought to be the Cu/Zn catalyst for the low temperature shift converter located downstream of the preheat tubes.
Results of exposing UNS R56404 forging and pipe product forms to liquid mercury over the 25°-232°C range while highly stressed at & beyond the alloy’s yield point via three loading modes are reported. Included are: sustained load 90 day C-ring tests, slow strain rate tensile testing, and rippled slow strain rate cyclic tensile loading.