Experimental study on generation characteristics of weld buckling distortion in thin plate

Abstract

In this study, a systematic investigation on the effect of welding conditions on longitudinal bending and angular distortions generated in welded thin plate was experimentally performed with a focus on whether or not the weld buckling distortion occurs. Real-time measurements of temperature profiles and distortion behavior during welding of thin plate were also performed for a more detailed understanding of generation process of weld distortion in thin plate. As the results, longitudinal bending distortion monotonically increases, in which the degree is different depending on the plate thickness, with the weld heat input. Meanwhile, angular distortion does not show a linear increase with the weld heat input and can be arranged coordinately by a curve convex to the parameter of mechanical melting zone, which was proposed based on the theory of inherent strain by authors in previous study, when the weld buckling distortion does not occur. In this regard, however, angular distortion also approximately monotonically increases with either the weld heat input or the parameter of mechanical melting zone, when the weld buckling distortion occurs. This is because the angular distortion-generation process proceeds in the following two stages; angular distortion is primary generated due to inhomogeneous temperature distribution through thickness during welding and secondary in association with buckling behavior during cooling process after welding. This secondary stage results in buckling-induced large angular distortion in welded thin plate. It was thus clarified that it is important to understand the generation characteristics of weld buckling-induced inherent stress and strain especially in the secondary stage for accurate predicting and controlling the weld buckling distortion in thin plate.