Three-dimensional mapping of the residual stress field in a locally rolled aluminium alloy specimen

Detrimental residual stresses that occur in welded joints can be removed by rolling the weld seam. In this study we show that rolling could be applied to much thicker-section welds than has previously been attempted. A residual stress field introduced by localised rolling of an aluminium alloy specimen was studied to establish whether the plastic deformation caused by rolling would be sufficient to treat thick-section welds. It was modelled using finite element analysis and characterised using detailed neutron diffraction measurements. During rolling, plastic deformation occurs through the entire thickness of the specimen and strongly compressive residual stresses are created in the rolled area. Some features of the three-dimensional residual stress field, such as a region of tensile stress beyond the end of the rolled area, could be detrimental to structural integrity. It is recommended that these should be taken into account in the design of rolling-based weld treatment and surface treatment processes.