Fatigue crack propagation in welded joint of austenitic steel for nuclear power engineering

The crack propagation characteristics were obtained for Cr-Ni type austenitic steel 08Kh18N10T under variable stress in the individual zones of a welded joint on a pipe. Measurements of the threshold deviation of the stress intensity factor, ΔKp, showed that the root zone of the pipe welded joint was the weakest point as concerns crack propagation. The threshold values obtained for the filler metal on the pipe outer surface were considerably greater than those for the root zone of the welded joint and slightly greater than those for the base material and for the transition between the joint and the base material. The measured propagation response showed that the rate of fatigue crack propagation was for the base material higher by up to one order for low ΔK than for the filler joint and the root zone of the joint. (J.B.). 5 figs., 3 tabs., 6 refs