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Spray Tips: Continuous Galvanizing Line

January 01, 2019
Source: ASM International

The schematic diagram shows the pot region of a continuous hot dip metal coating line. Degradation of sink rolls and other rolls associated with continuous galvanizing lines is due to zinc and/or aluminum reactions with iron from the steel rolls. These reaction products degrade the rolls and affect the surface of the steel products. Some of these reaction products are called dross particles.

The most commonly used zinc baths are galvanized zinc with minor concentrations of aluminum, zinc with 0.5 wt% Al, and zinc with 55 wt% Al and minor amounts of silicon. Currently, coatings consist of tungsten carbide/cobalt powders applied via HVOF or detonation gun technology. The success of these coatings depends on the spray parameters, powder manufacturing method, and sealant system. The key to increased life is to reduce the amount of free cobalt in the coating.


Subject Classifications

Materials Processing and Treatment | Coating

Materials Processing and Treatment | Heat Treating

Materials Processing and Treatment | Thermal Spray Technology

Metals and Alloys | Aluminum

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