Experimental measurement of biaxial thermal stress fields caused by arc welding

The strain field within thin steel plates during gas metal arc welding has been studied using resistance strain gauges and digital image correlation, allowing the initial formation of stresses around the weld seam to be observed. Major features of the transient stress field have been identified, and are explained with reference to the underlying thermal and mechanical processes. A comparison of stresses occurring during bead-on-plate and butt welding shows they are very similar. The assumptions and limitations associated with determination of the stress state are addressed, and the application of such methods to the problem of reducing welding residual stresses is discussed.

► The formation of residual stresses during arc welding has been observed.
► Aspects of the transient thermal stress field, and their underlying causes, are discussed.
► Plastic strain is confined to a relatively narrow region around the weld line.
► Stresses during bead-on-plate and butt weld geometries are very similar.
► Two methods of strain measurement during arc welding are compared.