FEA of Electrode Velocity Effect on Thermal Cycle and Residual Stress in Pipes Connected by Multi Pass Weld

Abstract

This study is involved on modeling a standard welding procedure specification (SWPS) for a multi pass weld of pipes, and the effect of increase in electrode velocity on thermal cycle and induced residual stress have been investigated. A double ellipsoidal model for weld heat source density and an appropriate coordinate system with a rotation around the pipe is adopted to simulate properly the sequence of weld properly. A 3D finite element analysis (FEA) is carried out using a commercial code and the validation of the model is confirmed by previous works. Temperature‐dependent thermo‐mechanical behavior for material properties and birth and death technique for elements of deposited filler layer are employed to model the weld. By a thermal analysis and uncouple residual stress the peak temperature, cooling rate, weld pool geometry and induced residual stress in heat affected zone (HAZ) are evaluated. The results indicate that peak temperatures against the time reasonably follows the sequence of weld and by increasing electrode velocity, the value of peak temperatures in a certain point of HAZ is reduced. The final hoop residual stress pattern for points underlying in HAZ influenced by the rise in electrode velocity, however the axial residual stress seems to be more influenced.