Influence of cemented carbide binder type on wear initiation in rock drilling – Investigated in sliding wear against magnetite rock

Abstract

Cemented carbides, containing hard WC grains in a ductile Co binder, are commonly used as the rock crushing part of rock drills. They generally work well and show moderate and gradual wear in rock drilling applications. However, due to health issues, an alternative to Co is sought for, which will not compromise the performance. In the present work, the initiation of wear of cemented carbides with the two alternative binders Ni and Fe are investigated and compared to the common Co containing material in a sliding test. The sliding counterpart is magnetite, representing a rock type generally causing slow wear of the cemented carbides.The results show that magnetite is immediately transferred to the cemented carbide thus forming thin layers, mainly on top of the binder, and WC grain fragments are removed. The chain of events is similar irrespective of binder, however the severity shows a strong dependence. The cemented carbide grade with the Ni binder shows relatively rapid wear initiation, compared to that with the Fe binder that shows moderate initiation and that with Co that is barely worn at all.