Cyclical Chips Formation during Machining of Titanium and Titanium Alloys

Abstract

Turning of titanium alloys which is characterized with low cutting speeds and high tool wear, poses considerable problems due to the poor machinability of titanium. In this work, the process of cyclical chip formation during machining of titanium and titanium alloys was studied and analysed. Titanium alloys of BT1.00, BT3-1 and BT-5.1, of diameter 100 – 200 mm and length 600 – 800 mm, was used as the work piece. Experimental results show that the width of chip formation zone during cutting of titanium alloys is very minimal. As a result of this, increasing the plasticity (elasticity) properties of volumes of titanium alloys lead to the ceasing of the formation of cyclical chips. This study has however analysed and pointed out that the best wear resistant cemented carbide tool was BK6 and cemented carbide tool BK8 was only 75 - 80% as good. At a cutting speed V = 60 m/min, a durability of S30 minutes was attained. The durability increased to 45 – 50 minutes when the cutting speed was reduced to V = 50 m/min and a stable wear of 0.30 - 0.35 min was maintained for about 70% of the working period. Majority of the chip elements increased in the width of localized shear plane and the contact layer with increase in cutting speeds.