CRACK INITIATION AND GROWTH RESISTANCE IN PRESSURE-VESSEL MATERIALS

The crack initiation and propagation has been studied in two typical pressure vessel alloys ( 1 2Mo and 2 1 4 Cr -1 Mo) in the temperature range of 30-400°C using elastic-plastic fracture mechanics approaches. The study has also been conducted in the heat affected zone (HAZ) of weldments from these alloys. The J and CTOD crack growth resistance curves have been obtained based on average crack growth as well as the maximum crack growth approaches. The latter approach may be used to obtain a conservative estimate of crack growth resistance from subsize specimens. With increasing temperature the crack initiation toughness and tearing resistance are found to vary in different manners, i.e. the initiation toughness increases though crack growth resistance decreases and vice versa. The HAZ toughness appears to be less than that of the base metals. © 1990.