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| Abstract No.: |
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Scheduled at:
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Wednesday, June 07, 2017, Hall 28 3:00 PM
Equipment / Consumables & Powders, Wires, Suspensions I
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| Title: |
Dry-sliding wear of laser clad nickel aluminide / chromium carbide coatings against cast iron
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| Authors: |
Sven Bengtsson* / Höganäs AB, Sweden
Senad Dizdar/ Höganäs AB (publ), Sweden
Karin Gong/ Chalmers University of Technology, Sweden
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| Abstract: |
The wear of piston rings in large marine two-stroke diesel engines is a major engine maintenance cost. Applying e.g. a nickel aluminide coating with its good oxidation, corrosion resistance and high temperature strength, lowers the total maintenance cost. In the past this material and mixes with chromium carbide have been applied to pistons by thermal spraying. Using laser cladding a suitable microstructure can be formed while at the same time avoiding cracks and bonding issues. Gas atomized powders were tested by laser cladding as fully pre-alloyed powder or as mixes of nickel aluminide powder and chromium carbide powder. The carbides grow as bundles of elongated carbides in a Ni3Al/NiAl matrix. The matrix is normally equi-axed grains of Ni3Al and NiAl, but can change to a dendritic growth when the total amount of carbide decreases. The dry sliding wear-mechanism maps are generated by using block on ring test setup where coated blocks slide against cast iron rings. All alloys exhibited regions of plasticity-dominated wear and oxidational wear with a transition region in-between. All carbide-containing alloys showed lower friction and wear in comparison to the plain nickel aluminide alloy.
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