A study of micro hardness in the machining of Inconel 625 using TiAlSiN coated tools under dry cutting conditions
Ramesh Rajguru, Hari Vasudevan
Abstract
Inconel 625, a nickel-based super alloy, has a high tendency to form a work-hardening layer during the milling operation, resulting in further difficulty to process it. However, Inconel 625 is extensively used in the manufacturing of aero-engine exhaust and in many other industries due to its admirable mechanical properties. Further, tighter environmental regulations and higher coolant and disposal costs associated with the nickel-based super alloys are forcing researchers to think about dry machining. PVD TiAlSiN coating is the most suitable in dry machining of difficult-to-cut materials. In this context, this study analysed the micro-hardness of machined surface and sub-surfaces up to 200 µm during the dry milling with coated tool. It was observed from the in-depth analysis of process parameters as well as their interaction effect with TiAlSiN-coated tool in dry conditions that it has a low influence on the micro-hardness gradient in the top layer of machined surface. A blend of the lowest level of cutting speed with the central level of feed per tooth, radial rake angle and depth of cut resulted in minimum micro-hardness due to the balancing of the effects of mechanical and thermal deformation.