Influence of Vibration Stress Relief (VSR) on the Residual Stress and Microstructure in Welded Plate of DH36 Low Alloy High Strength Steel

Welded components of DH36 low alloy high strength steel are widely used in offshore oil platforms and ships building. Stress reliving treatments to these welded components is of great importance. Vibration stress relief (VSR) method is an novel technology to release stress in welded components. In this study, 10×200×1000mm DH 36 steel plates were welded and then treated by VSR for about 1 hour. After the treatment, the residual stress was decreased by 29-72% at the welded toe, where the highest residual stress occurs. The metallographic microstructure of the joint was not changed by VSR. Investigation by transmission electron microscope (TEM) revealed that the amount of dislocations was increased at the welded toe. We hope this study can provide theoretical and practical fundamentals for widespread application of VSR on welded offshore engineering components.