Measurement of surface residual stresses and testing mechanical properties of high-strength steel butt joints obtained by hybrid laser/gas metal arc welding

Abstract

Hybrid laser/gas metal arc welding was applied to join the thick high-strength steel in square butt joints with narrow gaps. An X-ray diffraction technique was used to measure the surface residual stress distribution of high-strength steel by a hybrid laser/gas metal arc welding in a butt joint configuration. The influence of welding parameters, including welding speed and wire feeding rate, on the residual stress distribution and mechanical properties of the hybrid weld was experimentally studied. The obtained results show that there exist high compressive transverse and longitudinal residual stresses along the centerline of the weld. However, high tensile transverse and longitudinal stresses are located in the nearby heat-affected zone. An increase in the welding speed definitely decreases the residual stress concentration. A good weld quality of high-strength steel butt welds without cracking or defects can be achieved by a hybrid laser/gas metal arc welding technique.