Welding processes apply complex thermal loading and result in complex material behaviour. To be able to model the process, and accurately predict the resultant residual stresses, requires the application of advanced modelling methods and a detailed understanding of material behaviour.
As part of a government funded program to develop the capabilities needed for future generations of nuclear power plant, we developed a method for modelling power-beam welding processes including the prediction of residual stress. We drew on our previous knowledge of weld modelling, to create a method that would enable accurate prediction of residual stresses whilst also being computationally efficient.
To validate our method a number of electron beam welded and laser beam welded specimens were created, state of the art methods were then applied to measure the residual stresses in these specimens. We used these residual stress measurements to validate the predictions from our models for the electron beam welded specimens.
Through this and previous projects we have developed extensive knowledge in the field of weld modelling, including:
• How to develop weld modelling processes for both arc welding and power beam processes
• What simplifying assumptions can be applied to make the modelling methods efficient and what the limitations of these assumptions are
• How materials behave during the weld modelling process and how to model this? What methods are available to experimentally validate modelling predictions and how best to apply them
• How to make use of residual stress predictions as part of a process to ensure through life structural integrity
• How to predict post-weld distortion and design welding processes to minimize it.
