Material property relationships for pipeline steels and the potential for application of NDE

The oil and gas industry in the USA has an extensive infrastructure of pipelines, 70% of which were installed prior to 1980, and almost half were installed during the 1950s and 1960s. Ideally the mechanical properties (i.e. yield strength, tensile strength, transition temperature, and fracture toughness) of a steel pipe must be known in order to respond to detected defects in an appropriate manner. Neither current in-ditch methods nor the ILI inspection data have yet determined and map the desired mechanical properties with adequate confidence. In the quest to obtain the mechanical properties of a steel pipe using a nondestructive method, it is important to understand that there are many inter-related variables. This paper reports a literature review and an analysis of a sample set of data. There is promise for correlating the results of NDE measurement modalities to the information required to develop relationships between those measurements and the mechanical measurements desired for pipelines to ensure proper response to defects which are of significant threat.