Influence of the Crystallographic Orientation of a Directionally Solidified Nickel-Based Superalloy on Macroscopic Grinding Forces

Abstract

In aerospace industry profile and surface grinding processes are key operations in the machining of turbine blades. The calculation of grinding forces depending on process parameters, e.g., depth of cut and feed rate, offers the possibility of pre-designing the process in order to reduce efforts for preliminary experimental tests and to avoid mechanically overloading the workpiece. For this purpose, a material-dependent macroscopic force model for isotropic materials was determined in a preliminary work. However, turbine blades are usually made of directionally solidified superalloys that can withstand higher temperatures than common alloys leading to a higher engine efficiency. In this paper, the effects of the anisotropic mechanical properties of these materials on grinding forces are discussed. Therefore, experimental studies on a surface grinding process were carried out using directionally solidified MAR 247 samples consisting of four different primary orientations with respect to the grinding direction. The forces were measured with a dynamometer and the results were used to decide whether the crystallographic orientation has to be implemented in a macroscopic grinding force model.