A Time Saving Method to Compute Multi-Pass Weld Residual Stresses

Abstract

In order to obtain the residual stress field resulting from the welding process, numerical simulations of multi-pass welding have demonstrated their efficiency and have become an interesting alternative to practical measurements. However, in the context of engineering studies, it remains a difficult task to compute residual stresses for a very high number of passes with reasonable computation times. In this paper, a time-saving method is proposed to simulate the welding process, ensuring an accurate reproduction of the residual stress field with drastically reduced computation times. The method consists in including in the simulation only the last deposited pass, or a reduced number of appropriately selected passes. For a given material and a given heat input, the choice of remaining passes depends on the geometrical parameters. The method is applied to various geometries of austenitic pipes girth welds, which have been widely studied in the literature and standards. The results, confronted to multipass simulations including all the passes, and to literature results, are very satisfactory. Quasi-identical residual stress fields are computed in both cases with computation times divided by a factor comprised between 7 up to 12. Further computations are in progress on other configurations than girth-weld pipes, and more complex 3D geometry like J weld of bottom head nozzles.

Numerical simulation of Rapid Additive Forging (RAF) process

“…Moreover, it has also been noticed that the last weld passes also have a significant impact on the final residual stress fields. This kind of considerations has led to modelling strategies that do not include all the passes in the numerical analysis, but only a reduced number of them [4]. This approach looks promising for additive manufacturing, for which a very high number of passes is to be considered.…”

Investigating the Effects of Process Variables on the Residual Stresses of Weld and Laser Cladding

“…Furthermore, in the development of the model to account for spatial and temporal variation, interpass temperatures and times are being utilized from the welding process. Rossillon and Depradeux [5] have shown that the inclusion of the last deposited pass or a reduction in the number of passes resulted in highly satisfactory residual stress distributions in comparison with multi-pass simulations of austenitic pipe girth welds. The present study indicates that a 3D multi-pass idealization is of secondary importance in this case.…”