Influence of temperature, grain size and cobalt content on the hardness of WC–Co alloys

Author(s):  
Yu.V Milman ◽  
S Luyckx ◽  
IT Northrop
2015 ◽  
Vol 1114 ◽  
pp. 13-21 ◽  
Author(s):  
Mario Rosso ◽  
Ildiko Peter ◽  
Federico Gobber

Circular saw blades are used exclusively for cut-off work, ranging from small manual feed operations, up to very large power fed saws commonly used for sectioning stock as it comes from a rolling mill or other manufacturing processes for long products. The teeth profile, as well as the tooth configuration are of fundamental importance for the blade performances; through a combination of blade rigidity and grinding wheel condition a good quality surface finish is attained for tools of commercial standard. The materials used for the production of circular saw blades are ranging from high speed steel to cemented carbides. In particular, cemented carbides, being characterized by high hardness and strength, are used in applications where materials with high wear resistance and toughness are required. The main constituents of cemented carbides are tungsten carbide and cobalt. Tungsten carbide imparts the alloys the necessary strength and wear resistance, whereas cobalt contributes to the toughness and ductility of the alloys. The WC-Co alloys are tailored for specific applications by the proper choice of tungsten carbide grain size and the cobalt content. The grain size of the tungsten carbide in WC-Co varies from about 40 µm to around 0.3 µm, the cobalt content from 3 to 30 wt%. The coarse grained hardmetals are mainly used in mining applications, the smallest grain size being about 3 µm and the minimum cobalt content 6 wt%. The grain size of tungsten carbide in the metal cutting industry, as well as for universal applications lies in the range of 1-2 µm. However, with the advent of near net shape manufacturing and thin walled components, the use of submicron carbide is growing, since their high compressive strength and abrasive wear resistance can be used to produce tools with a sharp cutting edge and a large positive rake angle.In this invited paper, a general overview on the actual trends in the choice of the best material when cutting special alloys will be presented and discussed. Based on the recent and past literature some examples of their up-to-date application, such as circular saws used to cut stainless steels and some high strength alloys, are talk over.


Author(s):  
Ida Borgh ◽  
Peter Hedström ◽  
Tomas Persson ◽  
Susanne Norgren ◽  
Annika Borgenstam ◽  
...  

2014 ◽  
Vol 875-877 ◽  
pp. 1344-1351
Author(s):  
Jian Bing Cheng ◽  
Si Qin Pang ◽  
Xi Bin Wang ◽  
Xi Bin Wang ◽  
Chen Guang Lin

This work contributes to a better understanding of wear mechanisms of ultrafine cemented carbide cutting tools used in turning operation of superalloy and high strength steels at high cutting speeds. The main objective of this work is to verify the influence of grain size and the cobalt content of ultrafine cemented carbide tools on tool life and tool wear mechanism. The main conclusions are that grain size and the cobalt content of ultrafine cemented carbide tools strongly influence tool life and tool wear involve different mechanisms. The wear mechanisms of different grain size and the cobalt content of ultrafine cemented carbide tools observed on the rake face at these conditions were adhesion and notch, at the end of tool life, adhesion was the main wear mechanism at higher cutting speeds.


2005 ◽  
Vol 36 (7) ◽  
pp. 1927-1936 ◽  
Author(s):  
B. Y. C. Wu ◽  
C. A. Schuh ◽  
P. J. Ferreira
Keyword(s):  

2007 ◽  
Vol 1049 ◽  
Author(s):  
Siphilisiwe Ndlovu ◽  
Karsten Durst ◽  
Heinz Werner Hoeppel ◽  
Mathias Goeken

AbstractThe effect of the cobalt content and WC grain size on the deformation behaviour of WC-Co hard metals was investigated by studying materials with a varying WC grain size and cobalt content. The WC grain size ranged from 2.65 to 0.25 µm and the binder content ranged from 6 to 15 wt%. Single and multiple scratch tests were conducted using a Nano indenter with a Berkovich diamond tip and the load ranged from 5 to 500 mN with a tip sliding velocity of 10 µm/s. Several damage mechanisms were observed and these show a combination of ductile and brittle wear. The bulk properties i.e. composite properties of the hard metal determine the wear in the 6 wt% Co samples on the other hand the 15 wt% Co samples exhibited a localised response to the wear i.e. the wear is determined by the individual phases in the hard metal.


2014 ◽  
Vol 966-967 ◽  
pp. 80-86
Author(s):  
Varunee Premanond ◽  
Onnjira Diewwanit

The objective of this work is to investigate the tribological behavior between WC-Co cemented carbide and austenitic stainless steel under repeated rotation sliding. Influences of cobalt content of commercial grade cemented tungsten carbide on friction coefficient and material transfer phenomena have been explored. Three grades of commercial WC-Co cemented carbide with similar medium WC grain size were employed; WC-12Co, WC-14Co and WC-19Co. The average grain size were ranges between 0.85-1.1 μm and the hardness of about 86-88 HRA have been given by the material maker. The composition analysis and the average grain size of tungsten carbide have been rechecked. Furthermore, the carbide grain size distribution was recorded and the fracture toughness was calculated for each WC-Co grade. The experiments were carried out using ball on disk test. The ball was made from SUS304 grade and the disk was fabricated by 3 grades of WC-Co cemented carbide. The friction coefficient was measured under dry sliding. The characteristics of contact surfaces were explored on the ball as well as on the disk after tests to reveal the presence of a metallic transfer on the WC-Co cemented carbide disk and the wear scar on the ball. The measurement results of wear volume on the stainless steel ball disclosed that maximum wear rate was found from the stainless steel ball rub against WC-19Co tool material.


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