Experimental study and statistical modelling of wire arc additive manufacturing of ER70S-6
摘要
Wire Arc Additive Manufacturing (WAAM) is a high-productivity technique for producing large metal components. Controlling bead geometry, microstructure, and mechanical properties remains challenging due to complex thermal cycles. In this study, ER70S-6 steel was deposited to investigate the combined effects of arc power and robot travel speed on bead geometry, hardness, wetting, and microstructural evolution. The microstructural analysis revealed refined acicular/Widmanstätten ferrite, a well-defined dilution zone with equiaxed grains, and a thin oxide layer enriched with Mn, Si, Al, and Fe. Porosity originated from oxide entrapment and gas retention. The response Surface Methodology (RSM) was used to model the process-response relationships and to identify the optimal parameters. Arc power was found to be the dominant factor, with robot travel speed contributing significantly. The optimized condition (2839 W, 7.5 mm/s) achieved a predicted hardness of 300 HV, an aspect ratio of 2.63, and a wetting angle of 60.8°, validated experimentally. The study demonstrates the predictive capability of RSM and provides guidelines for optimizing WAAM parameters for ER70S-6 steel components.