Machinability Study of Super Duplex Stainless Steel S32750 with Magnetorheological Fluid Assisted Nano Finished Cutting Tool Inserts

Abstract To improve tribological properties in the tool chip contact zone, coated carbide tool insert surfaces are nano-finished using magnetorheological fluid (MRF) with diamond abrasives. In order to polish surfaces without significantly increasing the danger of damage to the tool's cutting blades, the configuration of the magnetic particle chain feeding the abrasives is essential. The CNMG 120408-F3M IC807 ISCAR make coated carbide inserts as received have an average surface roughness of 90 nm on the rake face and 110 nm on the flank surface. This unique MRF-assisted tool finishing process results in surface roughness of the tool inserts of less than 30 nm on the flank and less than 48 nm on the rake face. Turning super duplex stainless steel under dry cutting circumstances encourages the use of environmentally friendly machining methods. The machinability characteristics of the nano finished inserts are investigated in the dry turning of S32750 super duplex stainless steel based on surface roughness, cutting force, and tool wear. Compared to unprocessed tools, MRF-assisted nano finished tools demonstrated up to 30% longer tool life spans. The average tool life for nano-polished inserts is 27 mins, compared to 19 mins for unprocessed inserts for a tool life criterion of max. flank wear land, VB = 500 µm, at a cutting speed of 108 m/min, a feed rate of 0.212 mm/rev, and a depth of cut of 1.2 mm. Turning an S32750 super duplex stainless steel material has also seen an 18% reduction in cutting forces attributed to the use of nano polished inserts that also provide excellent lubricity. In terms of cutting forces, flank wear, and surface roughness, the results show that nano polished inserts perform better than conventional inserts.