Sintering of Recycled WC-Co-Ni by Pulsed Electric Current Sintering

Reference	Presenter	Authors (Institution)	Abstract
12-041	Catia Fredericci	Fredericci, C.(Instituto de Pesquisas Tecnológicas do Estado de São Paulo); Da Silva, M.(Proart); Tertuliano, A.J.(Universidade de São Paulo); Machado, I.F.(Universidade de São Paulo); Rodrigues, D.(BRATS Sintered Filters and Metallic Powders);	The WC-based hard metals with the bonding phase of Co and Ni are widely used in machining cutting tools, components of oil drilling equipment, forming matrix, mining and civil construction industries. Due to the increasingly intense demand for recycled materials, there are some processes with emphasis on the recycling of hard metals. However, these processes are aimed at recovering the metals that will be used in new hard metal compositions and in other applications. The objective of this work was to verify the possibility of sintering WC-Co-Ni grinding residue, in order to obtain sintered compact discs, using a technique that is gaining space in the sintering process: Pulsed Electric Current Sintering (SPS or PECS). The results showed that nearly full densification (98.2 %) was attained, when the recycled powder was sintered at 1200 oC for 10 minutes by SPS. The hardness of this compact was 14.6 ± 0.5 GPa and the fracture toughness was 9.6 ± 0.5 MPa.m1/2. Inserts were prepared from the sintered compacts with 98.2 % densification, which were fixed in a machining tool holder. These were compared with two commercial inserts in the machining of SAE 1020 steel. The results indicated that the inserts prepared in this work have a useful life similar to that of commercial inserts (TPMR 160308 - WIDIA e TPGN 110304 – KORLOY) and suggested an alternative for recycling hard metals based on WC-Co-Ni grinding residues.
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