Experimental and numerical study of deformations and stresses in butt-welded plates

Abstract: Deformations and stresses in butt-welding of plates are studied. Temperatures, strains, residual stresses and change in gap width in front of the heat source are calculated and measured. In particular, the change in gap width in front of the heat source during welding and residual stresses after welding are studied. The change in gap width is of interest in automatic welding production, and the residual stresses are of importance in design of welded structures. The sensitivity for variation of the values of the material properties, plate width, welding speed and heat input are investigated. Also the influence of the tack-welding procedure is analysed. The finite element method is used in the numerical simulations. Temperature dependence of the material properties and phase transformations are considered. A thermoelastoplastic material model is used and plane stress conditions are assumed. Good agreements between calculated and measured values of the studied quantities are obtained. The risk for hot cracking is numerically studied. Low welding speed and high heat input increases the risk for hot cracks to occur. A method to measure residual deformations is presented. The white light speckle technique is used to record the released residual deformations. The method is destructive. Experiments are performed and compared with corresponding calculated values.