PR-182-124505-R04 Developing Tools to Assure Safety Against Crack Propagation

Recent industry experience is showing that modern lower grade steels (X60 to X70) are not having the same fracture behavior as older steels of the same grade. As a major consequence, past material qualification test methods may be no longer valid for these new steels and may not provide safe design guidance, both for the evaluation of the brittle to ductile transition temperature and for the prediction of ductile fracture arrest requirements. MAT-8-1 Project Phase 2 was specifically focused on brittle-to-ductile transition temperature assessment and may ultimately lead to reliable testing methods to evaluate the behavior of modern steels, to allow the industry to design safe gas pipelines. Specific small and full-scale experimental activities have been carried out, with the aim to verify the correspondence between the brittle-to-ductile transition temperatures determined using different small-scale sample geometries and comparing the results with four full-scale West Jefferson tests.