Performance of cryogenically treated CBN inserts on difficult to cut materials during turning

Machining of materials is recognized as removing unwanted materials by using different cutting inserts. In this research, cutting inserts used are CBN inserts and treated cryogenically at -196°C in liquid nitrogen chamber. The inserts are subjected to 30 hours of treatment in controlled atmosphere. The materials used are Titanium and AISI 440 C hard Martensitic Stainless steel. The cutting parameters are cutting velocity 30, 40 and 50 m/min with feed rate of 0.05, 0.10 and 0.15 mm/rev and depth of cut of 0.05, 0.75 and 1.00 mm. The performance evaluated was tool wear, surface roughness. Cryogenically treated CBN inserts produced less tool wear on titanium than AISI 440 C Martensitic stainless steel. The roughness produced was low at high cutting speed with low feed rate. Flank wear was not progressive and varied. In turning AISI 440 C stainless steel, built up edge formed in all cutting speed which is a common phenomena and lead to crater wear formation. The chips produced were saw tooth chips by both materials.