Feasibility of diagnosing corrosion cracking in main pipelines

With a view to assessing various diagnostic techniques for corrosion and stress-corrosion flaws, results of an in-pipe inspection of a pipeline section have been analyzed. The statistical data are presented in the form of plots of flaw dimensions versus their positions over the length of the inspected part of the pipeline and also over the pipe cross section. In order to identify common characteristics of corrosion and stress-corrosion flaws, results of the in-pipe inspection of the pipeline were analyzed, and it turned out that there are essential differences in most parameters of the corrosion and stress-corrosion flaws. The analysis took into account geographical features of the pipeline and protecting potentials in the inspected parts of the pipeline. The most essential differences between the corrosion and stress-corrosion cracking are in the distributions of the flaws over the inspected pipeline division. The pipeline sections with higher densities of stress-corrosion flaws contained smaller numbers of corrosion flaws, and vice versa. The ultimate aim of the reported research was to compare the opportunities offered by direct and indirect diagnostic techniques designed to detect corrosion cracking in main pipelines.