Papers by Keyword: Hard Steel

Abstract: Rapid tool wear is a major demerit of high-speed milling (HSM) applied to cutting of hardened steels, especially the AISI D2. This paper presents an attempt to maximize the tool life by experimentally investigating the effects of cutter’s helix angle, workpiece material hardness, milling orientation, and minimum quantity of lubrication upon tool wear in high-speed side milling of AISI D2, using coated carbide cutters. Effects of these four parameters were studied also upon surface roughness. Statistical analysis upon experimental data revealed that milling orientation was the most significant factor for tool life as well as for surface roughness. The paper also describes the mechanisms of wear undergone by the tools, by making use of SEM photographs and EDS microanalysis. The major wear mechanisms were chipping, adhesion, and diffusion.

Abstract: Tool life, surface roughness, and cutting forces have always remained extremely important output parameters of milling process. In this paper an attempt has been presented in order to study the influence of cutter geometry and cutter coating upon these three output parameters. Series of high-speed side milling experiments were done upon hardened AISI 4340 and AISI D2 steels using coated and uncoated carbide cutters. Mechanisms of wear occurring in different tools have been described in the paper using SEM photographs and micro-analysis of the tool surface. The analysis of experimental data shows that the coated carbide cutters having high values of helix angle and small values of rake angle, in the negative range, provide the better optimization of highspeed milling of hardened steels. Results imply that tool geometry and coating are influential upon cutting forces and tool wear but not upon surface quality. Introduction of MQL in the process leads the tool to fail abruptly because of the onset of chipping.