Performance appraisal of cryo‐treated tool by turning operation

Abstract

In the present investigation, PVD coated carbide inserts & uncoated carbide inserts were subjected to deep cryogenic treatment (-190°C) and machining studies were conducted on Stainless Steel using both untreated and deep cryogenic treated carbide cutting tool inserts. Micro-structural study, elemental characterization and crystallographic orientation were studied with the help of Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS) and X-ray Diffraction (XRD) respectively. Micro-hardness of the same specimens was evaluated using Vickers micro-hardness. The results indicated that cryo-treatment resulted information of hard and wear resistant η-phase carbides along with the improvement of tungsten carbide distribution in cobalt binder phase in metal matrix. The turning tests were conducted at three different cutting speeds (50, 70, and 90 m/min), feed rate (0.04, 0.05, 0.06 mm/rev) and depth of cut (0.1, 0.2, 0.3 mm). The influence of cryo-treatment on carbide inserts were evaluated in terms of flank wear of the cutting tool inserts, surface finish of the machined work-pieces and cutting forces. The results showed that cryogenic treatment significantly improved the average flank wear. The surface finish produced on machining the work-piece is better with the deep cryogenic treated carbide tools than when compared with the untreated carbide tools. Cutting force for cryo-treated inserts appeared to be less than non- cryo-treated insert. Tool life test was also conducted and results favored cryo-treated inserts. Also, a comparative study was done between carbide inserts cryo-treated at different conditions. FEA analysis using ABAQUS software was carried out to investigate the stress and temperature distribution at tool-workpiece interface.

Keywords- Cryo-treatment (CT), Carbide inserts, Surface roughness, Cutting force, Flank wear