Effect of cutting speed and CVD multilayer coating on machinability of Inconel 825

Abstract

The current study aims at investigating the effect of cutting speed (51, 84 and 124 m min⁻¹) as well as tool coating deposited using chemical vapour deposition (CVD) on machined surface roughness, tool wear characteristics, chip morphology and chip reduction coefficient (ζ) during dry machining of Inconel 825. Turning operation was carried out using ISO P30 uncoated cemented carbide and CVD multilayer coated (TiN/TiCN/Al₂O₃/ZrCN) insert with a constant feedrate of 0·198 mm rev⁻¹ and depth of cut of 1 mm. Chip morphology and tool wear were studied using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and optical microscopy. Results indicated CVD multilayer coated tool resulted in more machined surface roughness compare to it uncoated counterpart. However, coated tool demonstrated excellent resistance to crater and flank wear, and decrease in chip reduction coefficient during dry machining of Inconel 825.

Keywords:

• Multilayer coating
• Cemented carbide
• Inconel 825
• Chip morphology
• Chip reduction coefficient
• Tool wear