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Permanent link (DOI): https://doi.org/10.7939/R3496G
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Depositing Ni-WC Wear Resistant Overlays with Hot-Wire Assist Technology Open Access
- Other title
- Type of item
- Degree grantor
University of Alberta
- Author or creator
Guest, Stuart Dan
- Supervisor and department
Mendez, Patricio (Chemical and Materials Engineering)
- Examining committee member and department
Prasad, Vinay (Chemical and Materials Engineering)
Hamre, Doug (Apollo Machine)
Rajendran, Arvind (Chemical and Materials Engineering)
Chen, Weixing (Chemical and Materials Engineering)
Li, Leijun (Chemical and Materials Engineering)
Goldak, John (Mechanical and Aerospace Engineering, Carleton)
Department of Chemical and Materials Engineering
- Date accepted
- Graduation date
Doctor of Philosophy
- Degree level
Seven Ni-WC tubular wires utilized in this study were characterized by the nickel sheath area, powder composition, and overall initial carbide volume fraction of the wire prior to welding. The electrical resistivity of steel, stainless steel, and Ni-WC welding consumables were measured from 25-1200 oC. The electrical resistivity of steel and stainless steel welding consumables are greater than those reported in literature. Tubular Ni-WC resistivity is in good agreement with pure nickel values reported in literature.
A hot-wire electrode extension model was proposed to predict the current necessary to achieve the semi-solid temperature of the welding consumable at the weld pool free surface. The influence of a GTAW and GMAW leading heat source was quantified and found to play a significant role on the hot-wire melting.
The hot-wire GTAW process showed significant challenges due to excessive electrode contamination and it might not be viable for typical oil sands or downhole drilling equipment wear protection. GMAW using tubular Ni-WC wires was investigated as a more practical alternative and a range of welding parameters and shielding gases were explored. A previously undocumented phenomenon of the non-wetting behaviour of tungsten carbide on the molten weld pool free surface was observed with high speed videography. Carbide dissolution and non-wetting resulted in GMAW carbide transfer efficiencies of 20-70% within the range of parameters studied.
Hot-wire GMAW was deemed a viable alternative, with a deposition rate of 5.4 kghr-1, 33% carbide volume fraction, and ASTM G65 Dry Sand/Rubber Wheel Procedure A mass loss of 0.086 grams. Metallographic analysis did not show indications of carbide dissolution using the hot-wire assist technology with a GMAW leading heat source.
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- Citation for previous publication
Guest, S.D., et al., "Non-wetting behaviour of tungsten carbide in nickel weld pool: new loss mechanism in GMAW overlays", Science and Technology of Welding and Joining, Vol. 19, No. 2, pg: 133-141, 2014.
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