Welding Residual Distortions in Ring-Stiffened Pipes

Abstract

A fast and simple method for the determination of the residual deformation for a class of welding problems, ring-stiffened pipes, is proposed. The method can predictradial as well as angular distortion of the thin-walled pipe-ring-stiffener/flange assembly. The pipe and stiffener material is elasto-plastic. In particular, the accumulation of deformation in multipass welding is incorporated in the model. Each weld pass is treated separately. This facilitates the assessment of the influence of the sequence in which the weld passes are deposited on the residual deformation state. The method will be included in a conversational knowledge-based “expert” system for the production of a welded ring-stiffened pipe.

Simple thermo-elastic–plastic models for welding distortion simulation

“…The increasing power and capability of computer systems mean that direct, detailed computational simulations are feasible to some extent. However, simplifications seem to be necessary in practice, as noted by Josefson [3] and Lindgren [4] and, as noted by Bachorsky et al [5], it is important to keep computational times within a reasonable industrial time frame. Aside from the computational challenges, significant complexities arise because the thermal and mechanical properties of the weld zone and parent material are temperature-, time-and ratedependent, and they are subject also to step variations due to material phase state changes.…”

Influence of a welding sequence on the welding residual stress of a thick plate

“…Not only is it difficult to guarantee the dimensions of the work piece, but also the existence of welding residual stress will reduce the rigidity and fatigue strength of the metal structure. Therefore, it is important to construct a feasible welding sequence before welding in order to reduce the residual stress after welding, and, thus, guarantee the welding quality of the workpiece [10][11][12][13][14]. During production, researchers have accumulated a lot of experience on how to arrange the welding sequence [15][16][17][18][19][20][21][22], but the experience usually aims at a certain concrete work piece instead of a general suitability.…”

Analysis of welding distortion due to narrow-gap welding of upper port plug

“…However, simplifications seem to be necessary in practice [19], as noted by Josefson et al [20] and Lindgren [21], it is important to keep computational times within a reasonable industrial time frame.…”