Effect of interlayer delay on microstructure and bead geometry of wire arc additive manufactured low carbon steel components

Wire arc additive manufacturing (WAAM) is a layer-by-layer fabrication technique that enables the manufacture of large-scale parts at a higher efficiency. Multi bead depositions cause heat buildup, which rises the temperature of the previously deposited layer during WAAM. This causes process instabilities, resulting in variations from the required dimension and material property changes. In this research, the interlayer delay was increased from 40 to 120 s during the deposition of the low carbon steel walls. The effect of interlayer delay on bead height, width, hardness and microstructure were examined. It was observed that the temperature was reduced with an increase in interlayer delay, leading to a variation in wall height, width, hardness and microstructure. The wall width was decreased and the height of the wall was increased with an increase in the interlayer dwell time from 40 to 120 s. The hardness of the deposited parts was increased with an increase in interlayer delay due to fine grain microstructure. By changing the interlayer delay time, the study points the way toward tailoring the characteristics of low carbon steel wall structures made using wire arc additive manufacturing.