Characterization of shear stresses in nickel-based superalloy Mar-M247 when orthogonal machining with coated carbide tools

CHEN Shao-hsien¹, SU Sen-chieh², JEHNG Wern-dare¹

(1. Department of Mechanical Engineering, Chin-Yi University of Technology, Tai Chung, China;
2. Department of Mechanical Engineering, Chung Cheng University, Chun Yi, China)

Abstract:Mar-M247 is a nickel-based alloy which is well known as difficult-to-machine material due to its characteristics of high strength, poor thermal diffusion and work hardening. Calculation of shear stress by an analytical force model to indicate the effect of coating material, cutting speed, feed rate on tool life and surface roughness was conducted experimentally. Cutting tests were performed using round inserts, with cutting speeds ranging from 50 to 300 m/min, and feed rates from 0.1 to 0.4 mm/tooth, without using cooling liquids. The behavior of the TiN and TiCN layers using various cutting conditions was analyzed with orthogonal machining force model. Cutting results indicate that different coated tools, together with cutting variables, play a significant role in determining the machinability when milling Mar-M247.

Key words:Mar-M247; tool wear; orthogonal machining; shear stress