L51807 Characterization of Axial Flaws in Pipelines with a Focus of Stress Corrosion Cracks

This report presents the results of a series of projects that involved: (1) characterizing the behavior of crack colonies associated with stress-corrosion cracking (SCC); (2) developing failure criteria to provide safety without undue conservatism; and (3) developing criteria to characterize crack coalescence prior to SCC leaks. Analytical details are given for the various types of axial cracks, with a focus on short, deep cracks, patches of SCC cracks often found in field-digs, and deep, co-parallel cracks. All analyses were done in a fracture mechanics framework for use in developing criteria to ensure safety and assess the serviceability of natural gas transmission pipelines.