Investigations on the impact of cutting velocity on the dry turning characteristics of Nimonic 90 with TiAlN-carbide insert

Choice of cutting insert, cutting speed and environment for respective machining are critical for producing a component from any work materials. This improper selection of the above-mentioned factors causes cutting performance, production cost and environmental issues. The PVD-coated carbide tool is the most suitable tool for cutting Ni-base superalloys. So, the objective of the current work is to identify suitable cutting speeds along with cutting environments.

In this context, it investigated the turning performance of Nimonic 90 with a coated insert (TiAlN) at various cutting velocities under dry environments. The results of the present work indicate that at a cutting speed of 118 m/min, a high flame was generated in the cutting zone, whereas at 43 m/min no flame was observed. A higher adhesion of chip was observed at the cutting point of the insert at 43 m/min due to low cutting velocity, but a burnt chip was adhered at 118 m/min. A uniform size of smooth profile and the lower value of roughness and height parameters were observed on the turned surface at 71 m/min. A continuous form of chip was obtained at 43 and 71 m/min, whereas a burnt discontinuous form of chip was found at 118 m/min. A nose of the TiAlN-coated carbide inserts underwent substantial wear at 43 and 118 m/min due to attrition wear and high flame generation, respectively. But there was no nose wear at 71 m/min. A welding of the chip and the delamination of the coating were found at the face of the inserts at 118 m/min. Hence, a higher loss in coating elements was found at 118 m/min.

Based on the experimental results, it was revealed that the enhanced turning performance was achieved at a cutting speed of 71 m/min.