Optimised Modelling of Weld Metal Constitutive Behaviour in the Net TG4 International Weld Simulation and Measurement Benchmark

The NeT TG4 benchmark specimen consists of a three pass type 316L TIG slot weld in a AISI type 316L plate. Phase one of the finite element simulation round robin performed on TG4 by the NeT network made the assumption that the weld metal exhibits the same mechanical behaviour as parent material. A comprehensive series of material characterisation tests on weld metal has now been completed, and these have allowed the derivation of a number of mixed isotropic-kinematic material models specifically for weld metal. The derived models have been used to improve the predicted stresses in the TG4 benchmark specimen. This paper first reviews the weld metal materials testing programme, and then discusses the optimum material hardening model fitting strategy to use for austenitic weld metal. The derived material models are tested by using them to predict residual stresses in the TG4 benchmark, and validating the predictions against the extensive database of measured residual stresses, and distortions.