Influence of postweld heat treatment on the variation of residual stresses in 50 mm thick welded ferritic steel plates

Abstract

The effects of postweld heat treatment (PWHT) on residual stress levels in a submerged-arc weld in a 50 mm thick BS 1501-224 ferritic steel are examined. Surface and through-thickness measurements of residual stress were made before and after PWHT. The maximum residual stress was found in the direction parallel to the weld at about mid-thickness coincident with the initial root run. After PWHT the maximum residual stress (in the range 100–140 MPa) was in the same direction and location, and also at the surface. The maximum PWHT residual stresses were up to 50 MPa higher than predicted from earlier weld metal relaxation results. There was, however, agreement between maximum effective residual stress and stress relaxation results for this and earlier studies.