Examination of wear damage to rock-mining hardmetal drill bits. (August 2017)

• Record Type: Journal Article
• Authors: Jones, H.G.; Norgren, S.M.; Kritikos, M.; Mingard, K.P.; Gee, M.G.
• Is Part Of: International journal of refractory metals & hard materials. Volume 66(2017)
• Page Start: 1
• Page End: 10
• Publication Date: 2017-08
• Subjects: Rock drilling -- Impact wear -- Hardmetals -- Tribochemistry -- X-ray diffraction -- FIBSEM; Heat resistant alloys -- Periodicals; Refractory materials -- Periodicals; Metallography -- Periodicals; Alliages réfractaires -- Périodiques; Matériaux réfractaires -- Périodiques; Métallographie -- Périodiques; Heat resistant alloys; Metallography; Refractory materials; Periodicals; Electronic journals; 669.73
• DOI: 10.1016/j.ijrmhm.2017.01.013
• Languages: English
• ISSNs: 0263-4368

Abstract

Abstract: WC/Co mining bits from a drill head used for drilling holes for roof support bolts in a mine were examined using a focused ion beam scanning electron microscope (FIB-SEM). This was combined with energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) analyses to study the chemical interaction between the drill bit and the rock. It was found that at the surface of the buttons there was depletion of cobalt, change in chemistry of the remaining binder regions, and changes to the morphology of the WC grains. Tribochemistry calculations were done to understand the possible formation of silicides at the surface of the drill bits, and thus emphasise the importance of quartz content in rock on wear. The evidence of mechanical damage combined with chemical reactions is another step towards understanding the complete wear process in hardmetal mining tools. Highlights: The impact wear mechanisms on hardmetal drill bits from use in a mine was examined. Focused ion beam, electron microscopy and XRD were used to characterise the wear. WC fragmentation, Co-binder compression, oxide formation were found on the surface. Damage was only found at the surface with no signs of deeper rock penetration. Tribochemical calculations were done to understand possible Co silicide formation.