Fatigue Properties of Explosive Bonded 321/Q370qD Double-layer Metal Laminate Butting Weld Joints

Through axial pulse-tension fatigue test, fatigue properties of explosive bonded 321/Q370qD double-layer metal laminate butting weld joints were studied. The fatigue S-N curves and fatigue strength (2×106 cycles) under the confidence degree of 50% and 97.7% were attained by mathematical statistics calculation, and fatigue strength under two different confidence degrees was both higher than designing value. Specimen fracture surface were observed and the results manifested that most of fatigue cracks initiated from base-layer of the bonded plate butting weld joints and individual from clad. Some obvious fatigue striations and typical dimples could be seen at stable crack growth district and final fracture zone respectively. Fracture mechanics analysis indicated that the driving force of which component fatigue crack started from was relevant to products of cyclic yield strength and elastic modulus of different components of the bonded plate butting weld joints.