The Effect of Abrasive Water Jet Process Variables on Surface and Subsurface Condition of Inconel 718

Abstract

Experiments were carried out in Inconel 718 in order to investigate the effect of abrasive water-jet process variables on surface and subsurface condition. A Design of Experiments (DoE) approach was taken, considering variables such as water pressure, traverse rate, abrasive mass flow rate and abrasive grit size. The experimental variables were related to taper ratio, surface roughness of different zones in the machined surface and subsurface condition (deformation and crater depth). Statistical analysis was carried out in order to develop mathematical models which include process variable interactions and quadratic terms. This led to models with high correlation and prediction power which allow a better understanding of the process and can form the base for further process optimisation. The models were validated with additional experiments and showed good agreement with the water jet system. The results showed that water pressure has a nonlinear behaviour in the quality of the surface and sub-surfaces and that interaction between the variables had a significant effect on the quality of the surfaces and sub-surfaces generated by the AWJ.