ORAL

SESSION: CompositeThuAM-R9	5th Intl. Symp. on Composite, Ceramic and Nano Materials Processing, Characterization and Applications
Thu Oct, 26 2017	Room: Condesa III
Session Chairs: Martin Pech-Canul; Beatriz Ruiz Camacho; Session Monitor: TBA

12:00: [CompositeThuAM03]
TaC-Containing Ti(CN)-WC-Ni/Co Cermets for the Improved Machining Performance
Vikas Verma¹ ; B. V. Manoj Kumar² ; ¹, ROORKEE, India; ²IIT ROORKEE, ROORKEE, India;
Paper Id: 206 [Abstract]

Present research deals with the study of cutting forces and dominant crater wear mechanisms responsible for material removal from the cutting edge of TaC-containing Ti(CN)-WC-Ni/Co based cermet tools during machining. TiCN based cermet compositions Ti(CN)-5WC-20Ni and Ti(CN)-5WC-10Ni-10Co-5TaC (in wt.%) processed via conventional sintering and SPS were selected for turning operations performed for 0.5 mm/rev feed rate and 0.9 mm depth of cut at 133 rpm for 180 sec and 435 rpm for 60 sec against 304 stainless steel rod and results were compared with commercially available cemented carbide tip (CCT) tool. Representative images of polished surfaces of sintered cermets revealed core rim morphology. The size and the frequency of the carbide size appear to differ with the cermet composition and processing technique in the SEM (BSE) images of the processed cermets. Higher cutting forces resulted at lower speed compared to higher speed. At lower speed, cutting edge of the tool tends to plough into workpiece surface to a larger extent and as the cutting speed increases, cutting becomes steady with a consequent reduction in the cutting force. Among the investigated tool materials, lower cutting force is observed in SPSed Ti(CN)-5WC-10Ni-10Co-5TaC cermet. The worn tool surface of conventional Ti(CN)-5WC-20Ni cermet showed cracks, grain pull-out and fracture at 133 rpm, while the intensity of crack, grain pull-out, and fracture increased at 435 rpm. Hard asperities or wear particles act as sharp indenters and generate cracks, which on further propagation and intersection lead to grain pull-outs on the cermet tool surface. Worn tool surface of conventionally sintered and SPSed Ti(CN)-5WC-10Ni-10Co-5TaC cermet revealed increased resistance against crack or fracture. Presence of adhered layer beneath the tool face of SPSed Ti(CN)-5WC-10Ni-10Co-5TaC cermet protected the tool from getting damage by continous rubbing during machining. Worn surfaces of cemented carbide tip tool revealed deeper abrasion and grain pull-out at 435 rpm. Ploughing harder tungsten oxide into the workpiece during machining led to deeper abrasion.