Studies on cryogenically treated WC-Co insert at different soaking conditions

ABSTRACT

Tool wear and tool replacement significantly increases the machining time and subsequently increase the production cost. To enhance tool life, various surface modification techniques are adopted such as nitriding, hard coating, heat treatments, cyaniding, etc. In the present study, the tungsten carbide-cobalt (WC-Co) cutting tool is treated cryogenically at −196°C with the different soaking periods of 24, 48 and 72 h. The performance characteristics of the treated cutting tool are measured on Al6063 under turning operation at various machining conditions and the results are compared with untreated tools. An experimental design with Cutting velocity, depth of cut and feed rate as machining parameters have been evaluated, with roughness and tool wear rate as the output variables of the study. Minimum tool wear and acceptable level of surface finish are observed on cryogenically treated inserts and Al6063, respectively. An increase in the soaking period in a deep cryogenic environment leads to having excess tool wear and subsequently affects the surface finish. Twenty-four hours and 48 h deeply cryo-treated insert exhibits fine microstructural observation which reveals the formation and distribution of η carbide particles, in turn, results in improved hardness and wear resistance. The conformity of the above results is ensured through Vickers micro-hardness and surface morphological studies.

KEYWORDS:

• Aluminum
• WC-Co
• cryogenic
• tempering
• microstructure
• turning
• wear
• hardness