Innovative Nondestructive Method Determines Fracture Toughness of In-Service Pipelines

This companion paper to IPC04-0357 demonstrates that ABI® can determine fracture toughness of in-service pipelines nondestructively in the field, enabling meaningful fitness-for-purpose decisions without cutting specimens from operating pipelines.

While yield strength determines the pipe's resistance to plastic collapse under internal pressure, fracture toughness determines its resistance to crack propagation from defects such as stress corrosion cracks, seam weld flaws, or mechanical damage. Both properties are needed for a comprehensive fitness-for-purpose assessment — and ABI® provides both from a single in-situ test.

The paper introduces pipeline operators to ABI®'s dual capability: yield strength for B31G-type corrosion assessments and fracture toughness for crack-like defect assessments using engineering critical assessment (ECA) methods such as API 579 / BS 7910. This combination makes ABI® the only in-situ technique that can provide both of the fundamental material properties needed for pipeline fitness-for-purpose evaluation.

The field applicability of fracture toughness measurement is particularly significant because conventional fracture toughness testing requires large specimens (typically 25 mm thick) machined from pipe cutouts — a destructive, expensive process that requires pipeline shutdown and segment removal.