Measurement of residual stress in arc welded lap joints by cosα X-ray diffraction method

The welding residual stress of lap joints of thin steel sheets was measured by the cosα X-ray diffraction method and compared with the numerical simulation. The longitudinal residual stress in the region near the weld is close to the yield strength of the base metal. The welding residual stress distribution is asymmetrical on the two plates and two sides of the weld because of the asymmetrical geometry of the lap joint. A higher residual stress was observed on the lower plate of lap joints. The longitudinal residual stress has almost the uniform distribution along the weld line except near two ends. The influencing length near two ends of the weld line is about 20-30 mm. The maximum tensile value of the longitudinal residual stress of the lap joint of the high strength steel TS590 is higher than that of the mild steel TS270.