Influence of sintering condition on the tool wear of NbC-based Ni binder-cemented carbide cutting tools

This research had the objective of investigating the viability of using niobium carbide-Nickel binder-cemented carbides as an alternative material for cutting tools. The high hardness and high wear resistance associated with niobium carbide (NbC) fulfills one of the main requirements for cutting tool material. In order to achieve this objective, insert tools with square shapes were manufactured using samples at 5 different grades. The samples were developed with different ratios of NbC carbide/Ni binder, compaction parameters, and sintering conditions. The samples were qualified in terms of micro-hardness and physical properties. The inserts were also qualified in terms of their macro-geometry, surface finish, and cutting edge micro-geometry. Machining experiments were performed under different cutting parameters on tempered ANSI 4340 steel workpieces. Flank wear progression was the control parameter, and wear analyses were made using a CCD camera and SEM/EDS. The main wear mechanisms observed were abrasion, followed by adhesion, while no traces of tribooxidation and diffusion were observed. The results led to the conclusion that the ratio of NbC carbide/Ni binder had the greatest influence on wear, but the leading parameter is the sintering conditions.