Experimental study on residual stresses in stud welding based on X-ray diffraction and the blind-hole method

During the stud welding process, residual stresses are inevitably induced due to the significant temperature gradients and associated heterogeneous thermal expansion and contraction. These residual stresses significantly influence the mechanical properties of the welded structure. Quantitative evaluation of the welding residual stress distribution on the steel plate surface was performed using X-ray diffraction (XRD) and the blind-hole method. Results demonstrate that the radial residual stress initially increases and subsequently decreases with increasing distance from the weld ring. The circumferential residual stress is characterized as compressive throughout the measured region, also exhibiting an initial increase, followed by a decrease, and a subsequent increase with greater distance from the weld center. Both radial and circumferential stresses form a compressive stress zone within the weld and its immediate vicinity, with a peak value of approximately 170 MPa. The significant solid-state phase transformations occurring in the weld metal and the adjacent heat-affected zone lead to the development of compressive stresses upon cooling. The compressive stresses observed in the base metal region, far from the weld, are likely attributable to the initial rolling stresses inherent to the steel plate.