Abstract
Low cycle fatigue strengths of load-carrying cruciform joints with incomplete penetration and strength under-match between base metal and deposit metal were studied. Fatigue tests were performed on specimens with five matching conditions and two sizes of incomplete penetration. Test results revealed that failure life was governed by crack propagation, and that crack propagation paths differed by matching and loading conditions. Also, fatigue strength of the joints was compared regarding the degree of strength matching and size of incomplete penetration. It was found that the effect of the strength matching on the fatigue strength becomes large in low cycle fatigue region by significantly reducing fatigue life of the specimen in the case of under-matched joints.
