Machinability of Hard Martensitic Stainless Steel and Hard Alloy Steel by CBN and PCBN Tools by Turning Process

Hard turning of martensitic stainless steel is gaining importance in all manufacturing sectors like automobile and aerospace industries. Machinability of materials depends on surface roughness, tool wear, cutting forces, specific cutting pressure and work material hardness. In this research hard martensitic stainless steel AISI 440 C and SCM 440 alloy steel was used as work materials. CBN and PCBN cutting tools were used to turn the work materials. The operating parameters used were cutting velocity 100, 125, 150, 175 and 200 m/min with feed rate of 0.10, 0.20 and 0.30 mm/rev with constant depth of cut of 1.0 mm. The length of turning was 150 mm and 750 mm. Machinability of both materials and tools was evaluated in terms of roughness, flank wear, cutting force and specific cutting pressure.