DETERMINATION OF THROUGH THICKNESS RESIDUAL STRESS IN THICK BUT JOINT

Abstract

Through thickness residual stresses in mild steel butt welded joints were investigated by Deep Hole Drilling method. To study the feasibility of Deep Hole Drilling technique to measure the residual stresses, first of all, validation of DHD technique was carried out. The validation of DHD technique was performed by four point bent test of a rectangular bar. During the Four point bend test, the bar was deformed partially plastic in order to induce the residual stresses. Afterthat the theoretical residual stresses were computed by strain gauges mounted on the bar at different locations along the thickness of the bar. A standard DHD procedure was adopted to measure the change in diameter. Afterthat the experimental obtained residual stresses by DHD technique were compared to check the accuracy of the DHD method. After validating the DHD technique, the residual stresses were determined in the single V groove and double V groove butt welded joints. The through thickness longitudinal and transverse residual stresses were represented for the mild steel welded joints.