Performance evaluation of cryogenically treated and tempered tungsten carbide insert on face milling of grey cast iron

Abstract

The objective of this study is to evaluate the wear progression of cryogenically treated (treated and tempered) and untreated tungsten carbide inserts during the face milling of grey cast iron which is a commonly used material in machine tool beds and automotive components due to low cost, high vibration damping capability, and easiness of manufacturing. Commercially available uncoated tungsten carbide inserts with around 6% Cobalt (Co) content were selected for the study. Flank wear and nose wear were taken as the performance evaluation criteria. The results showed that the cryogenically treated and tempered samples have better tool life than the untreated inserts which is ascribed to the martensitic phase transformation of Co from α-Co (FCC) to e-Co (HCP) and the formation of compressive residual stress in the treated insert samples. This was confirmed with the help of metallographic analysis by studying the magnetic saturation and coercivity of the untreated and treated samples. This work focuses on the effect of cryogenic treatment on the magnetic properties of tungsten carbide insert which results in higher wear resistance of about 12% to 20%.