Study of the influence of hydrostatic ball burnishing pressure on the surface roughness of Inconel® 718 and Ti6AL4V

Abstract

Superfinishing processes, such as hydrostatic ball burnishing, improve the surface quality of components and generate compressive residual stresses that can increase the performance and service life of parts to which these technologies are applied. One of the main advantages of hydrostatic ball burnishing technology is that it can be integrated directly into machining centres. In this way, time and errors arising from clamping changes or the need for specific tooling are reduced. Moreover, as this is a process in which a ball rolls over a surface, the feed speed that can be reached is very high (even the maximum allowed by the machine), considerably reducing machining and finishing times. This study has analysed the burnishing parameters that minimise surface roughness on components made of the heat-resistant superalloys Inconel® 718 and Ti6Al4V. The influence of the hydrostatic pressure of burnishing on the material was evaluated. For this purpose, the tests were carried out with two levels of hydrostatic pressure. It was found that with the use of 30 MPa it is possible to improve the surface quality Sz by up to 51% for Inconel® 718 and 81% for the titanium alloy