Differences of corrosion fatigue behaviors among 316LN base metal, 316LN heat-affected zone and 308L weld metal in a safe-end weld joint in borated and lithiated high-temperature water

Abstract Corrosion fatigue behaviors of 316LN base metal (BM), 316LN heat-affected zone (HAZ) and 308L weld metal (WM) in a safe-end weld joint were investigated in borated and lithiated high-temperature water. It was found that the 316LN HAZ showed the highest environmentally assisted fatigue (EAF) effect and the 308L WM had the lowest EAF effect. The corrosion fatigue cracking mechanisms are discussed in 316LN BM, 316LN HAZ and 308L WM by considering the effects of welding residual strain, corrosion resistance and δ-ferrite.