Analysis of temperature and surface finish of Inconel 718 during grinding utilizing different grinding wheels

Abstract

Nickel-based superalloy Inconel 718 is widely used for aeronautical applications, such as blades and discs of aircraft engines, and therefore is generally submitted to a grinding process in order to meet the required surface finish and dimensional accuracy. However, the mechanical and thermal properties of Inconel 718 make it a material with low machinability (difficult-to-machine material). Therefore, the proper selection of abrasives is of high importance, when aiming to improve process efficiency. White aluminum oxide (WA) and green silicon carbide (GC) abrasives are the most common conventional abrasives employed in the grinding of nickel-based superalloys, and their different properties can be decisive when it comes to the success of the process. In this sense, this work sought to evaluate the performance of two conventional abrasives (WA and GC) in the grinding of Inconel 718 with cutting fluid applied with a conventional technique. Five different cutting conditions were tested. Surface finish (Ra and Rz parameters) and cutting region temperature were used to assess grinding performance. The results showed that, compared to WA, grinding with the GC wheel reduced roughness in 14% and 19% for Ra and Rz, respectively, even though this produced higher cutting region temperatures (55% higher in general). However, for more severe cutting conditions (e.g., higher values of radial depth of cut), the characteristic wear mechanism of the GC wheel further increases cutting region temperature, resulting in surface finish deterioration.