Full-scale dent rebound test of X65 steel oil pipeline

Dents may negatively affect pipeline service safety and accessibility of the pigs or inspection detectors. To predict the rebound conditions after removal of the stone support and improve the understanding to fitness for service assessment, full-scale dent rebound test was conducted for an X65 steel oil pipeline in China. The test results show that both dents of smooth type and sharp type have rebound over 40%, and degrees of such rebound decrease with increases in depths of such dents. Through excavation test of pipeline bottom dents, it is found that actual measured results coincide well with above test results. Due to impacts of actual forms, eclipse deformation, pressures, scratches and other factors related to metallic losses, actual measurements reveal higher dispersity.