GRINDING OF NICKEL-BASED SUPER-ALLOYS AND ADVANCED CERAMICS

Abstract

This paper studies grinding of Inconel 718, Hastelloy, and some advanced ceramics. A newly developed ultra-high-speed grinding machine and a conventional grinding machine were used for the experiments. The ultra-high-speed grinding machine is equipped with a specially designed and built spindle unit that can run up to 200 m sec⁻¹ and deliver a maximum output of 12 kW. The surface roughness and residual stress values of the ground super-alloys and advanced ceramics were measured using a profilometer and a residual stress analyzer, respectively. The ground surfaces were also assessed using a scanning electron microscope. The effect of h _m (undeformed chip thickness) on surface topography of the difficult-to-machine materials was also investigated. A higher grinding wheel speed produces a smaller cutting depth and undeformed chip thickness, and thus smaller grinding force, decreased residual surface stress, and better surface finish. High productivity and good surfaces with ductile streaks could be obtained by employing ultra-high-speed grinding, even at very large wheel depths of cut such as 400 μm, without cross feed.

Keywords:

• Al₂O₃ grinding wheel
• Advanced ceramics
• CBN grinding wheel
• Conventional grinding
• Depth of cut
• Diamond grinding wheel
• Ductile streaks
• Grinding force
• Material removal rate
• Residual stress
• Super-alloys
• Surface roughness
• Ultra-high-speed grinding
• SEM analysis
• Undeformed chip thickness

Acknowledgments