A parametric study of thermal and residual stress fields in lined pipe welding

Abstract

Welded lined cylindrical structures such as boilers, pressure vessels and transportation pipes are widely used in the oil and gas industries because an inexpensive outer layer is protected from corrosion by a thinner expensive layer, which is made of a corrosion resistant alloy (CRA). Welding in the lined pipe is of two different types, where the first one, so called weld overlay (lap-weld), is deployed to seal the liner with the outer pipe whilst the other one, known as girth welding (butt-weld), is deposited to join two specimens of lined pipe together. Therefore, the precise prediction of the thermal and residual stress fields due to the combination of two different types of circumferential welding is a major concern regarding welded lined pipes to avoid sudden failure during service. Six parametric studies have been conducted primarily to examine the influence of welding properties (weld overlay and girth welding materials), geometric parameters (weld overlay and liner) and welding process parameters (heat input) on the thermal and residual stress fields. All predicted results obtained from a 3-D FE model based on the ABAQUS code are validated against small-scale experimental results. Furthermore, in this study, the effect of mesh size has been investigated.