ABSTRACT
One of the most acute problems of transit pipelines in Ukraine is the initiation and the growth of stress corrosion cracks which can eventually lead to a catastrophic fracture. Laboratory investigations (Krasowsky et al. 2012) of this degradation mechanism reveal the great impact of high stresses on the crack growth rate. Distribution of stress corrosion defects observed over time in pipeline also shows that the density of the defect colonies increases essentially with pressure, and the hoop stress that equals approximately 65% of yielding stress is the threshold value for their appearance (Zheng et al. 2000). It is also noted in work (Zheng et al. 2000) that the abovementioned stress level is presumably a lower bound estimation for the crack initiation threshold.
