Sustainability Assessment and Machinability Investigation of Austenitic Stainless Steel in Finish Turning with Advanced Ultra-Hard SiAlON Ceramic Tool under Different Cutting Environments

This paper presents the evaluation of the performances of the various cooling-lubrication techniques (dry, compressed-air cooled, flooded and minimum quantity lubrication) applied in turning of austenitic stainless steel Nitronic 60 with new-generation SiAlON ceramic tool in terms of cutting force, tool wear, cutting temperature, and surface roughness. Machining experiments were performed in a heavy-duty lathe machine tool under cutting conditions associated with varying cutting speeds (51, 67, 87, and 111 m/min), feed rates (0.12, 0.16, 0.20, and 0.24 mm/rev) and a constant depth of cut (0.4 mm). Consequently, analysis on machined surface roughness and tool as well as crater wear mechanism was made by using scanning electron microscope with an embedded energy dispersive X-ray analyzer for comprehensive understanding of the process. Finally, the Pugh matrix environmental approach has been proposed for sustainability assessment in finish turning process under various cooling-lubrication strategies. Among the four pre-cited cutting environments, the cutting fluids were applied to the cutting zone in sprayed-jet form by MQL technique significantly outperformed due to the lower environmental and health impacts. Also, it was observed that both main cutting force and surface roughness reduced with the increase of cutting speed whereas, with feed, both force, roughness and temperature increased but tool wear reduced. The results indicate that machining with MQL technique provided environmental friendliness, cleaner production and helped to enhance sustainability.