STUDY OF RESIDUAL STRESS IN PRESSURE VESSEL STEELS.

This investigation determined the levels of residual stress found in three pressure vessel steel weldments using the blind hole drilling and Battelle chip removal techniques. Surface residual stresses both longitudinal and transverse to a multipass submerged arc weld seam were measured in a heavy section A543 Class 1 weldment made with a high strength welding electrode. Residual stresses perpendicular and parallel to the weld seam were high and tensile at the weld surface in the center of the weldment length, but decline sharply as the cut face is approached. The maximum tensile stresses were less than the yield strength. Large residual compressive stresses were found at the center thickness of the weld on the cut face. A737 microalloyed steel weldments were also made using the submerged arc process and a matching strength electrode. Nearly full stress relief could be achieved after a treatment of 2 hrs at 550 degree C.