The effect of repair welds on the high temperature low cycle fatigue life of the nickel base superalloy IN738LC

This paper considers the effects of repair welds on the high temperature low cycle fatigue behaviour of the alloy lN738LC. The welding processes considered include electron beam. TIG and laser beam welding. In all except the case of one TIG welded sample welding is found to lead to a reduction in fatigue life by approximately an order of magnitude. The mechanism for failure is different for each welding method considered but in all cases premature failure can be attributed to poor weld quality In the one case of successful welding the welded sample was found to behave in a similar manner to that of the virgin alloy.