Mechanical stress improvement process

摘要

A process for reducing the residual welding stresses in the weld metal, heat-affected zone and in the adjacent base metal of steel piping that have been butt welded to each other end to end by means of a circumferential weld which comprises mechanically introducing compressive stresses in said weld metal, heat-affected zone and adjacent base metal higher than their individual yield strengths but not exceeding their ultimate strengths in compression.