0
TECHNICAL PAPERS

A Comparison of the Tribo-Mechanical Properties of a Wear Resistant Cobalt-Based Alloy Produced by Different Manufacturing Processes

[+] Author and Article Information
H. Yu

School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK

R. Ahmed1

School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UKr.ahmed@hw.ac.uk

H. de Villiers Lovelock

 Deloro Stellite, Cheney Manor Industrial Estate, Swindon SN2 2PW, UK

Stellite is a registered trade name of Deloro Stellite Company Inc.

Even if the loading is approximated as 0.1% (0.13N), the contact diameter (2a) will be 9μm.

1

Corresponding author.

J. Tribol 129(3), 586-594 (Jan 09, 2007) (9 pages) doi:10.1115/1.2736450 History: Received March 15, 2006; Revised January 09, 2007

This paper aims to compare the tribo-mechanical properties and structure–property relationships of a wear resistant cobalt-based alloy produced via two different manufacturing routes, namely sand casting and powder consolidation by hot isostatic pressing (HIPing). The alloy had a nominal wt % composition of Co–33Cr–17.5W–2.5C, which is similar to the composition of commercially available Stellite 20 alloy. The high tungsten and carbon contents provide resistance to severe abrasive and sliding wear. However, the coarse carbide structure of the cast alloy also gives rise to brittleness. Hence this research was conducted to comprehend if the carbide refinement and corresponding changes in the microstructure, caused by changing the processing route to HIPing, could provide additional merits in the tribo-mechanical performance of this alloy. The HIPed alloy possessed a much finer microstructure than the cast alloy. Both alloys had similar hardness, but the impact resistance of the HIPed alloy was an order of magnitude higher than the cast counterpart. Despite similar abrasive and sliding wear resistance of both alloys, their main wear mechanisms were different due to their different carbide morphologies. Brittle fracture of the carbides and ploughing of the matrix were the main wear mechanisms for the cast alloy, whereas ploughing and carbide pullout were the dominant wear mechanisms for the HIPed alloy. The HIPed alloy showed significant improvement in contact fatigue performance, indicating its superior impact and fatigue resistance without compromising the hardness and sliding∕abrasive wear resistance, which makes it suitable for relatively higher stress applications.

FIGURES IN THIS ARTICLE
<>
Copyright © 2007 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 3

XRD patterns of: (a) alloy powder; (b) cast alloy; and (c) HIPed alloy

Grahic Jump Location
Figure 4

The fractographs after the un-notched impact test on: (a) cast alloy; and (b) HIPed alloy

Grahic Jump Location
Figure 5

Average volume loss of cast and HIPed alloys after the dry sand rubber wheel tests

Grahic Jump Location
Figure 6

The wear scars after the dry sand rubber wheel tests with sand B on: (a) cast alloy; and (b) HIPed alloy

Grahic Jump Location
Figure 7

Average disk volume loss of cast and HIPed alloys after the ball-on-flat wear tests

Grahic Jump Location
Figure 8

Schematic representation showing the ball-on-flat sliding wear tests between: (a) cast disk and WC–Co ball (some wear on the ball); and (b) HIPed disk and WC–Co ball (no appreciable wear on the ball surface)

Grahic Jump Location
Figure 10

The stress cycles to failure of cast and HIPed alloys after the rolling contact fatigue tests

Grahic Jump Location
Figure 11

The wear tracks after the contact fatigue tests on: (a) cast alloy, 3.6GPa; and (b) HIPed alloy, 3.6GPa

Grahic Jump Location
Figure 9

The wear scars after the ball-on-flat tests of (a) cast alloy; and (b) HIPed alloy

Grahic Jump Location
Figure 1

Schematic illustration of the cup assembly for the rolling contact fatigue tests

Grahic Jump Location
Figure 2

The SEM images showing the microstructure of: (a) powder cross section; (b) cast alloy; and (c) HIPed alloy

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In