L51478 Ductile Fracture of Pipelines – Correlation between Fracture Velocity and Plastic Zone

This study examines the relationship between ductile tearing accompanying ductile crack extension and the arrest behavior of line pipe steel. Ten pipeline steels were selected to represent the spectrum of current manufacturing technology for X-70 pipe and detailed tensile properties were determined. The purpose of the study was to examine whether the extent of plastic deformation correlates with fracture velocity and/or arrest, and whether its extent can be predicted from metallurgical, geometric, and stress data. The results suggest that the total deformation accompanying fracture is not affected by work hardening rate or by the existence of fracture surface separations.