An insight into microstructure and machining performance of deep cryogenically treated cemented carbide inserts

Cryogenic treatment is one of the potential techniques to enhance cutting tool performance. The present work investigates the microstructure and machining performance of cemented carbide (WC-Co) inserts through deep cryogenic treatment. For this, ISO P30 WC-Co inserts were exposed to deep cryogenic treatment (-196 degrees C), accompanied by tempering at 200 degrees C. The cryogenic treatment cycle helps to develop eta (eta) phase carbides by redistributing cobalt (Co) phase on the surface of cryogenically treated WC-Co inserts. Microhardness of specimens indicated a slight increase in the hardness of cryogenically treated inserts than its untreated counterpart. A comparative performance evaluation between cryogenically treated tungsten carbide insert and the untreated insert was studied by turning of AISI 316 austenitic stainless steel through tool flank wear, crater wear, and chip morphology. Machining operation was carried out by considering three different cutting speeds (i.e. at 100, 150, and 200 m/min.) with constant feed rate and depth of cut of 0.2 mm/rev and 1 mm, respectively. After cryogenic treatment, significant improvement in the average flank wear and crater wear of WC-Co insert was observed. The enhancement of tool wear in the cryogenically treated insert is explained in detail by analyzing their microstructures.