An Investigation on Turning of Hard Steel using Coated Carbide Inserts

Employing conventional machining operations in material removal type manufacturing processes for processing difficult-to-machine hard materials through some ways and means is the focus of research by machining research groups across the globe since long. This gives considerable advantages over the grinding process in terms of higher material removal rate, better surface integrity of the work surface, etc., although grinding is commonly used for material removal of quite hard materials along with their finishing. In this paper, machinability of hard AISI 4340 steel is explored employing groove-type chip breaking coated carbide inserts under various cutting velocity and feed at dry condition. Hardened AISI 4340 is considered to be a difficult-to-machine material, and hence, recommendable machining conditions need to be found out. Favourable flat continuous chip is acquired at a cutting velocity of 231 m/min and at a feed of 0.08 mm/rev. At 391 m/min cutting velocity, cutting edges are detected to have worn-out quite fast.