Through-thickness distribution of residual stresses in Q345qD butt-welded steel plates

Welding residual stress measurements were performed on 16-, 40-, 60-, 80-, and 100-mm-thick, welded Q345qD steel plates. The through-thickness stresses are almost uniformly distributed in the thin specimen (16 mm). In 40-mm-thick specimen, the stresses exhibit slight fluctuations as function of thickness. The through-thickness longitudinal and transverse stresses generally exhibit C-shaped distributions in thicker specimens (60, 80 and 100 mm), while longitudinal stresses exhibit Σ-shaped distributions in these specimens at the weld centerline. High longitudinal stress (≥250 MPa) regions occur predominantly at the surfaces and centers of the cross-sections, while high transverse stress regions occur predominantly in the surface layers. The longitudinal stress is almost always tensile at the mid-thickness regions of the welds, while the transverse stress is compressive. The longitudinal and transverse stresses distributions generally range from −250 to 550 MPa. Commonly used empirical equations for residual stresses distribution were modified to expand their range of application based on the data obtained in present work.