Title: Premature failure mechanism of the cemented carbide blade in drilling Wansheng-limestone with water jet

Authors: Xiaofeng Yang; Hongwei Zhou; Yong Kang; Re Xia

Addresses: School of Mechanics and Civil Engineering, China University of Mining and Technology, Beijing, Beijing, 100083, China; Key Laboratory of Hubei Province for Water Jet Theory and New Technology, Wuhan University, Wuhan, 430072, China ' School of Mechanics and Civil Engineering, China University of Mining and Technology, Beijing, Beijing, 100083, China ' Key Laboratory of Hubei Province for Water Jet Theory and New Technology, Wuhan University, Wuhan, 430072, China ' School of Power and Mechanical Engineering, Wuhan University, Wuhan, 430072, China

Abstract: The premature failure of the drill bit seriously influences the efficiency and security of rock drilling. The premature failure mechanism of the cemented carbide blade on the drill bit is studied in drilling Wansheng-limestone with water jet. Experiment results showed that transgranular fracture is the main morphology of premature failure of cemented carbide blades in drilling Wansheng-limestone with water jet. Based on the experimental results and mechanical model analysis of the impact stress of the quartz grain, it is showed that the high content of quartz grains in Wansheng-limestone and the excessive speed of the water jet are the main causes of brittle fracture of the cemented carbide blades. Furthermore, the cooling of excessive speed water jet brings more hcp-Co phases than fcc-Co phases in the blade which may put the cemented carbide blade at higher risks of brittle fracture by the impact of quartz grains.

Keywords: cemented carbide blades; Wansheng limestone; drilling; water jet speed; premature failure; drill bit failure; water jet drilling; impact stress; quartz grains; brittle fracture; cooling.

DOI: 10.1504/IJMPT.2015.072556

International Journal of Materials and Product Technology, 2015 Vol.51 No.4, pp.321 - 331

Accepted: 10 Feb 2015
Published online: 19 Oct 2015 *

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