Abstract
The fatigue strength of welded joints has been investigated in synthetic sea water. The welded beam which contains yield strength magnitude tensile strength has been fatigued at R=0.1. The small welded specimens of which residual stress is not high enough to be yield strength has been tested at σmax=σy condition. The results of both tests coincided well for each other. The automatic detection of fatigue crack initiation life has been developed by using eddy current detector. This method was effective even in synthetic sea water. It has been revealed that the fatigue crack initiation life shares 10% in fracture life in synthetic sea water, and 20% in air.
