Surface degradation mechanisms of cemented carbide drill buttons exposed to iron ore rock drilling
2016 (English)In: Proceedings of the 17th Nordic Symposium on Tribology - Nordtrib 2016, 2016Conference paper (Refereed)
The wear behavior of cemented carbide rock drill buttons is influenced by many factors, which include the composition and microstructure of the cemented carbide material, plus the conditions of the rock drilling operation, such as drilling parameters, drill button geometry and the nature of the rock material. Depending on the type of rock and on the drilling procedure used, the cemented carbide is exposed to substantially differing mechanical and thermal conditions. Under conditions of high mechanical stress and high temperatures, typical for drilling in highly abrasive rocks such as granite, the worn cemented carbide buttons are usually very smooth, with the roughness limited to within the size of individual WC grains. When drilling under conditions of moderate mechanical stress and high temperatures, typical for drilling in low-abrasive rock, such as ores with e.g. magnetite, the surface damage of the buttons usually includes a macroscopic surface wear pattern, commonly referred to as “reptile skin”, in an otherwise smooth surface. The crack growth associated to the valleys of the reptile skin pattern eventually leads to catastrophic fracture of the button, unless the cracked surface layer is repeatedly ground off before the cracks grow too deep. So despite the low general wear rate, the wear life of drill buttons becomes severely restricted by the surface cracks. The present study focuses on revealing the degradation mechanisms behind the formation of the reptile skin. This is done by analyzing drill buttons exposed to different stages of degradation and wear from drilling in iron ore. The work is based on a combination of high resolution scanning electron microscopy (SEM), focused ion beam microscopy (FIB), energy-dispersive X-ray spectroscopy (EDS) and electron back scatter diffraction (EBSD).
Place, publisher, year, edition, pages
Rock drilling, iron ore, cemented carbide, wear
Research subject Steel Forming and Surface Engineering
IdentifiersURN: urn:nbn:se:du-23494OAI: oai:DiVA.org:du-23494DiVA: diva2:1050729
The 17th Nordic Symposium on Tribology - Nordtrib 2016, June 14-17, Hämeenlinna, Finland