Special Focus: Wear Protection
Increasing machinery lifetime with ultra-wear resistant coatings
Dr. Gary Heath looks at products available to support maintenance managers in their daily fight against wear.
El Dr. Gary Heath examina los productos disponibles para ayudar a los directores de mantenimiento en su lucha diaria contra el desgaste.
Dr. Gary Heath untersucht verfügbare Produkte zur Unterstützung von Instandhaltungsmanagern bei ihrem täglichen Kampf mit dem Verschleiß.
E Fig. 1. Plasma Transferred Arc Welding (PTAW).
● Spray and fuse: is the application of a special Ni-based hard metal powder by a flame spray process, followed by the subsequent fusion of this alloy to the substrate forming a metallurgical bond. Castolin Eutectic has developed a dedicated process and metal powder ranges. Successful power plant applications are drive shafts (rebuilding worn parts and replacing hard chrome), protection boiler tubes against erosion wear and corrosion, providing a smooth wear resistant surface in feeders and pumps, ball valves, ash screw feeders, etc.
● PTAW: Plasma Transferred Arc Welding is a welding process using metal powder where a high-energy electrical arc is created between the torch head and the base metal. Te powder is melted forming a thick liquid metal coating that fuses and metallurgical bonds to the substrate. PTAW offers up to 15kg/hr deposition rates and high quality, low dilution coating. Castolin Eutectic has developed a dedicated equipment
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rosion, abrasion, corrosion and cavitation are the main wear mechanisms reducing lifetime of machinery components in power plants. Te most important factors
influencing these wear types are: the content, the mass, the hardness, the relative velocity, humidity, heat and the angle of attack of the particles. Working alongside plant maintenance managers, many coating technologies have been developed through the years using diverse processes which have enabled these coating to reach unimaginable wear resistances.
Thermal spray processes Together with its maintenance experts, Castolin Eutectic has developed ranges of products for most thermal spray processes to support maintenance managers in their daily fight against wear. High Velocity Oxy/Fuel (HVOF), Arc spray, cold and hot powder flame spraying, plasma transferred arc welding (PTAW)
or cold polymeric materials, are some coating processes that have been successfully used for wearfacing in power plants.
Fig. 2. High Velocity Oxy/Fuel (HVOF).
Depending of the part and its working conditions, different coating processes are recommended:
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