Wear mechanisms of WC–Co drill bit inserts against alumina counterface under dry friction: Part 1 — WC–Co inserts with homogenous binder phase content

Malik Yahiaoui (1) , Jean-Yves Paris (1) , Jean Denape (1) , Alfazazi Dourfaye (2)

1 LGP - Laboratoire Génie de Production
2 Varel Europe (FRANCE)

The tribological behavior of commercial roller cone bit inserts was studied by using a rotary tribometer and abrasive alumina counterfaces. Three cemented carbide WC–Co inserts were selected with different cobalt content and WC grain size distribution. During tests, a nominal load was set at 264 N, the velocity at 0.5 m ⋅ s− 1 and the test time at 1 h. The experimental measurements were performed using load, torque, displacement sensors, an acoustic emission sensor and four thermocouples. These measurements showed that the friction coefficient and the mean contact temperature decrease with the cemented carbide's cobalt content. The acoustic emission energy displayed a clear dependence with the mean WC grain size and the WC–Co fracture toughness. It was also found that the insert's wear is proportional to the load but not to the time (or distance). Eventually, a third body approach clearly showed that the inserts and the counterfaces contribute to form an interfacial abrasive paste. The stability, the composition and the cohesion of this paste govern the tribological behavior of the WC–Co/alumina contact.

Mots clés: Roller cone bit; Cemented carbide; Acoustic emission; Contact temperature; Wear mechanisms; Third body

Domaines: Acoustique [physics.class-ph]; Mécanique des matériaux [physics.class-ph]

Malik Yahiaoui, Jean-Yves Paris, Jean Denape, Alfazazi Dourfaye. Wear mechanisms of WC–Co drill bit inserts against alumina counterface under dry friction: Part 1 — WC–Co inserts with homogenous binder phase content. International Journal of Refractory Metals and Hard Materials, 2015, vol. 48, pp. 245-256. ⟨10.1016/j.ijrmhm.2014.09.018⟩. ⟨hal-01154614⟩