TWI Industrial Member Report Summary 1086/2017
By Nicholas O'Meara
Background
Knowledge of welding residual stress is required to ensure welded structures are able to operate with sufficient resistance to certain failure mechanisms. In light of the difficulties associated with measuring residual stresses, finite element simulation can be used to predict stress evolution during welding processes. Solid state phase transformations, as experienced by ferritic steels, can affect residual stress evolution and should be accounted for in modelling approaches in certain cases. In this report, models to incorporate these effects using a widely used finite element modelling package are presented.
Key Findings
Predictions of microstructure and residual stress in a ferritic benchmark weld were made and compared with published measurements for this specimen.
- Flexible user subroutines can be written that allow phase transformation behaviour to be accurately simulated in ABAQUS;
- Low alloy steel phase transformations can significantly affect welding residual stresses;
- Beneficial compressive stresses in the HAZ of ferritic welds, induced by low temperature phase transformations have been simulated;
It is possible to accurately predict the micro hardness distribution in the weld using calibrated phase transformation models.
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