Investigation on thermal stress evolution induced by wire and arc additive manufacturing for circular thin-walled parts

Residual stress produced in wire and arc additive manufacturing (WAAM) is considerably complicated due to complex thermal process. Generally, the tensile residual stress often causes stress corrosion cracking and brittle fracture of fabricated components. It is necessary to investigate the thermal stress evolution and residual stress distribution of parts built in WAAM. In present work, a transient three-dimensional model is developed to research the thermal stress evolution and residual stress distributions of a circular thin-walled part. Meanwhile, the residual stresses generated in the substrate and deposited layers are measured by the hole-drilling method to verify the effectiveness of the model. The simulation result reveals that there exists a stress-releasing effect on the layers near the arc starting and ending points due to the special thermal characteristics of the circular component, and the features of residual stress distribution in different locations of the component are various. Along the fabrication path, the residual stresses of the component present larger fluctuations in the zones around the arc starting and ending points and exhibit smaller fluctuations in the areas nearby the midpoint. The residual stress distributions of the part from the simulation results offer a better understanding of the complex thermo-mechanical mechanisms in WAAM.