Effects of specimen geometry and loading mode on crack growth resistance curves of a high-strength pipeline girth weld

This work presents an investigation of the ductile tearing properties for a girth weld made of an API 5L X80 pipeline steel using experimentally measured crack growth resistance curves. Use of these materials is motivated by the increasing demand in the number of applications for manufacturing high strength pipes for the oil and gas industry including marine applications and steel catenary risers. Testing of the pipeline girth welds employed side-grooved, clamped SE(T) specimens and shallow crack bend SE(B) specimens with a weld centerline notch to determine the crack growth resistance curves based upon the unloading compliance (UC) method using the single specimen technique. Recently developed compliance functions and η-factors applicable for SE(T) and SE(B) fracture specimens with homogeneous material and overmatched welds are introduced to determine crack growth resistance data from laboratory measurements of load-displacement records.

This investigation is primarily supported by Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) through Grant 2009/ 54229-3 and by Agência Nacional de Petróleo, Gás Natural e Bio- combustíveis (ANP). The work of CR is also supported by the Bra- zilian Council for Scienti fi c and Technological Development (CNPq) through Grants 304132/2009-8 and 476581/2009-5. The authors acknowledge Tenaris-Confab Brasil and Lincoln Electric Brasil for providing support for the experiments described in this work. Helpful comments by a reviewer are gratefully acknowledged