Effects of welding columnar grain orientation and strain rate on corrosion fatigue behavior of Alloy 52/52M weld metal in high-temperature water

摘要

Corrosion fatigue (CF) tests of Alloy 52/52 M weld metal from a safe-end welding joint of reactor pressure vessel were performed in B/Li high-temperature water. The CF cracks developed preferentially in 52 Mw with columnar grain orientation at a 45 degrees - 75 degrees angle to cyclic loading axis, rather than in 52b with columnar grain orientation parallel to loading axis. The environmental assisted fatigue effects were significant under lower strain amplitudes and the effect of strain rate on CF behavior was not significant. The CF cracking mechanism involved with welding columnar grain orientation is discussed.