MICROSTRUCTURAL STUDY OF FAILURE PHENOMENA IN WC 94%-Co 6% HARD METAL ALLOY TIPS OF RADIAL PICKS
Sakuntala Nahak 1  
,  
Saurabh Dewangan 3  
,  
Sergej Hloch 4  
,  
Grzegorz Krolczyk 5  
,  
 
 
More details
Hide details
1
Jaypee University of Engineering and Technology, Guna-473226, India
2
Indian Institute of Technology (ISM), Dhanbad-826004, India
3
Department of Mechanical Engineering, National Institute of Science and Technology, Palur Hills, Berhampur, Odisha, 761008 Berhampur, India
4
Technical University of Kosice with a Seat in Presov, 080 01, Slovakia
5
Opole University of Technology, Proszkowska 76 St., 45-758 Opole, Poland
6
Poznan University of Technology, Piotrowo 3, 60-965 Poznan, Poland
CORRESPONDING AUTHOR
Saurabh Dewangan   

Department of Mechanical Engineering, National Institute of Science and Technology, Palur Hills, Berhampur, Odisha, 761008 Berhampur, India
Publish date: 2017-03-01
 
Adv. Sci. Technol. Res. J. 2017; 11(1):36–47
KEYWORDS
TOPICS
ABSTRACT
An excellent combination of hardness, strength, stiffness and high melting point has proved the WC-Co as an ideal material for tools which are used for metal cutting, coal mining, oil drilling, etc. The ongoing research in WC-Co is focussed on enhancing its wear resistant properties as much as possible. For the purpose, many attempts have been made to study the tribological behaviour of WC-Co for a long time. Researchers have used various grades of WC-Co in different working environment and accordingly they have characterized the wear phenomena involved in it. In this direction of research, the present paper makes an attempt to understand various wear behaviours in WC 94%-Co 6% hard metal alloy. WC-Co was used as a tip of the coal cutting tool, named, radial pick. Two radial picks have been taken for critical analysis through field emission scanning electron microscopy (FESEM) attached with energy dispersive X-ray spectroscopy (EDS). In this work, the failure behaviours in the tools have been divided into five categories: (1) Abrasion on individual grain; (2) Corrosion in carbide grains; (3) Fragmentation and removal of WC grains; (4) Pores in WC grains; and (5) Coal and rock embedding. The most possible reasons behind each failure phenomenon have been explained comprehensively with the help of high resolution microscopic images. However, it is usually observed that, initially, the tool gets minor cracks due to sudden impact. These cracks provide a path to the rock and coal particles to get entrenched inside the microstructure of cemented carbide. Finally, the intermixed external elements degrade the binder content (i.e. cobalt) and the tool becomes useless.