Relationship of the roller burnishing process parameters with the surface and subsurface properties of Inconel 718.

Abstract

Abstract This study aims to evaluate how deep the roller burnishing (RB) operating variables (temperature, number of passes and load applied by the bearing) affect the surface properties of an Inconel 718 part, in particular the surface roughness and nanohardness, based on nanoindentation results and image analysis techniques by confocal microscopy. It was evaluated how intensity these same variables of roller burnishing operations cause the phenomenon of strain-softening. Through the results obtained, it can be noted that, with up to two passes of RB, the surface roughness improves significantly. By increasing the number of RB passes, the phenomenon of strain-softening of deformation by stress of the Inconel 718´s sample was verified. For all RB operations (at room temperature and 310oC) the nanohardness levels (HV) were higher than those of the only turned sample, showing that, regardless of the test temperature the nanohardness of the part that underwent the RB operation increased. Metallographic analysis of the samples that underwent RB was performed and the abundant presence of the δ phase was observed. A gap was filled in research involving both the roller burnishing technique and the resulted properties of the Inconel 718.