High Productivity Rough Turning of Ti-6Al-4V Alloy, with Flood and High-Pressure Cooling

The performance of uncoated carbide tools when rough turning Ti-6Al-4V alloy were investigated under flood cooling and with 7 MPa coolant supply pressure. Up to twofold increase in tool life was achieved when machining at a speed of 80 m/min with a high-pressure coolant supply of 7MPa relative to a conventional overhead coolant flow. The dominant tool failure mode(s) were maximum flank and nose wear. Higher tool wear rates were observed when machining with flood cooling due to excessive temperature generation at the cutting interfaces, which accelerated tool wear. There was evidence of plastic deformation on the machined surface after machining with both flood cooling and 7MPa coolant supply at the higher speed conditions of 120 m/min. There was no evidence of surface hardening of the machined surfaces after machining in both coolant environments were investigated. This might be due to lower deformation forces that are unable to induce strain hardening of the machined surfaces.