Erosion & Erosion-corrosion Assessment of Materials for use in the Oil Sands Industry
Figure 4: Relative Erosion Resistance Values for Three Chrome White Irons
High Cr, high C white iron
Hypereutectic white iron
Near eutectic white iron
AISI 1018 steel std.
0 20 40 60 Relative erosion resistance Figure 5: Erosion Corrosion Rates and Individual Contributions
0.00E+00 2.00E-05 4.00E-05 6.00E-05 8.00E-05 1.00E-04 1.20E-04 1.40E-04 1.60E-04
Low C steel 140HB
Total EC rate EC = erosion corrosion.
Relative erosion resistance values are calculated for all materials, which provide an indication of the relative improvement of materials over the erosion resistance of standard AISI 1018 steel. Typical relative erosion resistance values for three chrome white irons with varying levels of chromium and carbon are shown in Figure 4 with the associated erosion scars. The influence of chromium and carbon on erosion resistance can be clearly seen.
Erosion Corrosion Slurry Pot Erosion Corrosion
Degradation of equipment by the combined mechanical and chemical interaction of erosion with corrosion can be especially severe and is a particularly critical problem affecting piping systems, pumps and processing/separation equipment.10
wear and electrochemical corrosion in a slurry environment is dependent on various parameters including:10
Medium C steel 615HB
Corrosion only Erosion only
High C steel 688HB
Total synergy 80 100
• temperature; • solution chemistry; •
•
factors associated with the impacting particles (properties, size, concentration, etc);
mechanisms related to slurry flow (angle of attack, velocity); and
• the composition, condition and properties of the material components in service or under test.
In response to the need to provide information on the performance properties of materials under combined attack conditions, the National Research Council has developed a novel slurry pot erosion corrosion tester. This provides the flexibility for assessing a diverse range of metallic and composite materials under a range of simulated conditions. The unit incorporates a three-electrode cell. This allows in situ electrochemical assessment to be carried out, thus enabling the individual contributions of erosion, corrosion and synergistic effect to be determined. Figure 5 shows the erosion-only, corrosion-only and synergistic values for three carbon steels of varying carbon content and hardness. The three steels were subjected to a slurry consisting of 35wt.% AFS 50–70 silica sand and 3.5wt% NaCl solution. It is evident that the total erosion-corrosion rate decreases with increasing carbon content and hardness. This is predominantly due to the erosion resistance of the steels and is reflected in the erosion-only rates. The three steels exhibited similar corrosion-only rates, while the synergistic levels generally showed a decrease with increasing carbon content and hardness, which can mainly be associated with the erosion resistance of the materials. A recent study11
using the
slurry pot erosion corrosion tester highlighted a novel microstructural assessment technique to track the susceptibility and extent of attack of two WC-based PTAW overlays. This was done by examining specific locations of test surfaces before and after exposure to controlled erosion corrosion conditions. This information was used in combination with quantitative erosion-corrosion wastage rate data to establish damage mechanisms for both overlays, and hence assess their suitability for use in specific environments.
Conclusions The complex interaction of erosive
The range of wear mechanisms found in the oil sands industry makes an understanding of the relative behaviour of different material classes essential. The utilisation of laboratory-based techniques for determining the performance of materials subjected to erosion and erosion-corrosion environments is particularly important for facilitating material selection decisions. The collaborative MWM programme has significant capabilities for assessing materials for such environments, thus helping to reduce the considerable costs associated with wear and corrosion in the oil sands industry. n
1. Available at:
http://www.oilsands.alberta.ca/resource.html 2.
6.
Canadian Association of Petroleum Producers Press Release, 2010–2025 Canadian Crude Oil Forecast and Market Outlook, CAPP, 9 June 2010. Available at:
www.capp.ca/aboutUs /mediaCentre/NewsReleases/Pages/2010-Oil-
Forecast.aspx#vQSci2JpDiyp (accessed 24 September 2010).
3. IHS CERA Special Report The Role of Canadian Oil Sands in US Oil Supply, CERA, 2010. Available at:
www.cera.com/aspx/ cda/client/knowledgeArea/
serviceDescription.aspx?KID=238# 44381, (accessed 24 September 2010).
4.
Llewellyn R, Winkel G, Reducing the cost of wear in mining and mineral processing, Innovation page, CIM Bulletin, 2007:2(8).
5. NRC Mining Wear Materials Factsheet, National Research Council of Canada, August 2010.
86
Clark HM, Hawthorne HM, Xie Y, Wear rates and specific energies of some ceramic, cermet and metallic coatings determined in the Coriolis erosion tester, Wear (Switzerland), 1999;233–5:319–27.
7. 8.
Llewellyn RJ, Yick SK, Dolman KF, Scouring erosion resistance of metallic materials used in slurry pump service, Wear, 2004;256(6)592–99.
Clark H, Llewellyn RJ, Assessment of the erosion resistance of steels used for slurry handling and transport in mineral processing applications, Wear (Switzerland), 2001;250–1(1): 32–44.
9.
Jones LC, Llewellyn R, Low angle scouring erosion behaviour of materials for processing and transportation of oil sands slurries, Paper no. 10140, CORROSION 2010, 14–18 March 2010, San Antonio, TX, NACE 2010.
10. Neville A, Reza F, Chiovelli S, et al., Characterization and corrosive bhavior of high-chromium white cast irons, Metallurgical and Materials Transactions A, 2006;37A: 2339–47.
11. Lu B, Luo J, Chiovelli S, Corrosion and wear resistance of chrome. White iron—a correlation to their composition and microstructure, Metallurgical and Materials Transactions A, 2006;37A:3029–38.
12. Jones M, Llewellyn RJ, Erosion-corrosion assessment of materials for use in the resources industry, Wear, 2009;267(11):2003–09.
13. Jones M, Llewellyn RJ, Erosion-corrosion assessmen of WC-based PTAW overlays, Paper 10138, CORROSION 2010, 14–18 March 2010, NACE 2010 Conference Proceedings, San Antonio, 2010.
EXPLORATION & PRODUCTION – VOLUME 8 ISSUE 2
Increasing erosion resistance
EC rate (cm3
/
h.cm2
)
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