The residual stress and distortion found in multi-pass welds are often influenced by the prescribed inter-pass temperature. In ferritic steel components, the severity of this influence is affected by solid-state phase transformation (SSPT) kinetics, which will depend on the overall heat input and cooling conditions. The development of an optimised welding procedure to mitigate weld residual stress (WRS) and distortion in these components can therefore necessitate an extensive test matrix, varying both preheat and inter-pass temperatures as well as the transient weld heat input.
Computational parametric studies provide an opportunity to dramatically reduce the cost and time associated with the development of welding procedure specifications. Welding procedures can be simulated using validated modelling approaches to examine parametric sensitivity and gain insights into optimal conditions for a given welding task. In the present study, a three-pass tungsten inert gas (TIG) groove weld in SA508 Gr.3 Cl.1 ferritic steel is numerically investigated using the ABAQUS finite element code with a user defined subroutine to incorporate the effect of SSPT kinetics. Parametric sensitivity is assessed whereby a representative heat input is applied to simulate weld deposition for each pass, and the inter-pass temperature is varied to examine its effect on WRS and distortion in the weldment. The implications of the overall heat input on cross-weld microstructure are also presented using this approach.