Modelling and optimising hybrid process of wire arc additive manufacturing and high-pressure rolling

Hybrid process of wire arc additive manufacturing (WAAM) and high-pressure rolling can build large-scale components with low detrimental residual stress (RS) and distortion. We developed an efficient coupled process model for a steel wall to simulate the interaction between WAAM deposition and rolling. The predicted RS distributions and wall dimensions agree well with experimental results. Cyclic variation of longitudinal tensile RS occurs during WAAM deposition and inter-layer rolling in clamped condition. The influence depth of deposition and rolling is characterised by the number of the underlying layers that are plastically deformed after each process cycle. For the inter-layer rolling with a flat roller, the rolling has smaller influence depth than the deposition; consequently, the rolling does not eliminate but rather contains the regeneration of WAAM tensile RS after thermal cycles. Rolling with a slotted roller intro-duces more tensile plastic strain and thereby more effectively reduces WAAM tensile RS and unclamping distortion. Compared to the inter-layer rolling, stacked-four-layer rolling has larger influence depth and hence achieves similar RS mitigation efficacy with fewer rolling operations, while post-build rolling has lower efficacy due to insufficient penetration. Therefore, stacked-layers rolling with slotted roller is rec-ommended for an optimal hybrid process of WAAM and rolling.(c) 2022 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).

Automated summary

The hybrid process of wire arc additive manufacturing (WAAM) and high-pressure rolling offers a solution for creating large-scale components with low residual stress and distortion. A coupled process model was developed to simulate the interaction between WAAM deposition and rolling, and its accuracy was verified by experimental results.