Investigations on machinability and machining stability of turning super duplex stainless steel

Super duplex stainless steels (SDSSs) combine austenite and ferrite in near equal proportions along with other alloying elements giving these steels excellent mechanical and chemical properties and making them of much use across industries. The same characteristics that give SDSS advantageous properties impair their machinability and make cutting of SDSS prone to unstable process-induced chatter vibrations. The focus of this paper is to hence investigate the machinability and machining stability of dry turning SDSS. Based on systematic experimental characterisation, we identify cutting force coefficients that characterise machinability and observe these coefficients to be relatively speed independent. We further observe surface characteristics to improve with cutting speeds. Using identified coefficients and measured dynamics, we predict the stability behaviour. Experimental validation confirms that the nose radius on cutting tools plays a significant role in improving the chatter vibration-free turning of SDSS. Our findings can instruct highperformance strategies for turning of SDSS.