Influence of clamping on distortion of welded S355 T-joints

Abstract

Welding almost always leads to some distortion of a structure due to its strongly time dependent and localised heat input. This distortion is usually undesirable and causes problems related to alignment and fit-up tolerances with adjacent structures. Considerable research has been carried out on different mitigation methods to reduce distortion to manageable levels; however, most of this has been for a single, simple set of clamping conditions. In practice, clamping is often required and the choice of restraint conditions and subsequent influence on distortion should be explored. This paper examines gas metal arc welds made on S355 T-joints under different clamping conditions. Measured welding temperatures and subsequent part distortions are shown for two different clamping conditions and compared to simulations. The interaction of the clamps and the workpiece due to the material reaction is examined by recording the transient clamping force. It is shown that the clamping condition strongly affects the welding distortion amplitude and might even alter the distortion mode.