Investigating the Effects of Flow Rate and Spraying Methods of CO2 Fluid on Tool Wear and workpiece Surface Quality in Cryogenic Turning of 304-L Stainless Steel

Increasing workpiece surface quality and reducing tool wear are always the most important ones in machining purposes. There are basic challenges to achieve optimum conditions for workpiece surface and tool life in different machining operations of austenitic stainless steel 304L due to low thermal conductivity and creating high temperatures at the cutting zone. Applying conventional cooling methods such as flood techniques does not usually provide desirable control of machining temperature. Also, their use often creates environmental problems. Recently, the cryogenic cooling process has been considered by researchers to reduce these problems in various machining methods. In this research, turning of 304L stainless steel using cryogenic cooling of CO2 have been studied to investigate the effect of flow rate and fluid spraying method on workpiece surface roughness and tool wear. For this purpose, the tool-workpiece contact zone has been cooled in five different methods of CO2 fluid spraying according to the number and position of the spraying nozzles (Up1, Up2, Down, Up1-Down, Up2-Down) and three different flow rates (12, 18 and 24 l/min). The minimum main flank wear of the tool was achieved in the Up1 cooling method and 18 l/min flow rate and the minimum workpiece surface roughness was achieved in the Up1 cooling method and 12 l/min flow rate. Regarding economic considerations to reduce the consumption of spraying flow of CO2 fluid and achieving the minimum main flank wear of the tool, built-up edge and workpiece surface roughness, the optimum spraying method and flow rate were obtained as Up1 and 12 l/min, respectively.