Abstract

MATUSEVICH, Ariel E; MANCINI, Reinaldo A  and  GIUDICI, Alejandro J. Fracture toughness evaluation of a natural-gas pipeline material. Rev. LatinAm. Metal. Mater. [online]. 2012, vol.32, n.2, pp.253-260. ISSN 0255-6952.

This paper presents the fracture toughness evaluation of the Ferreyra natural-gas pipeline, which has been in service in the city of Córdoba, Argentina, for more than forty years. For the pipeline under analysis, we obtained the critical stressintensity factors (K_Ic) of the pipe body and its weld seam, in a temperature range that included the lower part of the transition region, the upper shelf and the lower shelf. The determination of K_Ic was carried out indirectly, through empirical correlations between fracture toughness and standard Charpy V-notch impact test results. Because the wall thickness of the pipe under analysis did not allow the preparation of standard size Charpy V-notch specimens, impact tests were executed using subsize specimens. Impact energy results were converted to standard Charpy energy values using appropriate formulas. We show that the fractomechanical properties of the pipe weld seam are lower than those of the pipe body.

Keywords : Fracture toughness; gas pipes; Charpy V-notch impact test; critical stress-intensity factor.