Abstract
Selection of a good testing method is important in research on stress-corrosion of oil and gas pipelines, especially the transgranular type of cracking that occurs in a near-neutral pH environment with a relatively low crack growth rate. The distinct characteristics of this SCC phenomenon have posed some considerable challenges for laboratory research, and the uncertainties in the mechanism of crack initiation and propagation hinder an accurate lifetime prediction of the affected pipelines.
This paper summarizes, first of all, the findings on TGSCC of pipelines from both field evidence and laboratory tests. Results of slow strain rate testing (SSRT) carried out using tapered cylindrical tensile specimens are presented. SSRT is characterized by the large scatter in the resulting data and by the uncertainty in simulation of the actual operating conditions of oil and gas pipelines. SCC testing on full-size pipes represents a different approach with the capacity to simulate closely the environmental and loading conditions of pipelines. The experimental setup and methodology being developed are described and a comparison is made of the different test methods.
