Zinc Coated Iron and Steel
A new ASTM International standard describes methods of preparing surfaces of hot-dip galvanized iron and steel for powder coating and the application of powder coating materials.
The new standard, D7803, Practice for Preparation of Zinc (Hot-Dip Galvanized) Coated Iron and Steel Product and Hardware Surfaces for Powder Coating, was developed by Subcommittee D01.46 on Industrial Protective Coatings, part of ASTM International Committee D01 on Paint and Related Coatings, Materials and Applications.
Powder coating is a dry finishing process that uses finely ground particles of pigment and resin, electrostatically charged and sprayed onto a part to be coated. D7803 covers the surface preparation and thermal pretreatment of iron and steel products and hardware that have not been previously painted or powder coated. Bridges are one example of construction projects that are often built from hot-dip galvanized steel.
"D7803 explains the steps to achieve adherence of powder coating over galvanized steel so there is no adhesion failure of the powder system," says Thomas Langill, technical director, American Galvanizers Association and an ASTM member. "There has been increased interest in powder coating since it has no volatile organic compounds over corrosion protection, such as galvanized coating for color and appearance."
Langill notes that D01.46 is currently seeking powder coaters and inspectors to contribute to ongoing standards activities.
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CONTACT Technical Information: Thomas J. Langill, American Galvanizers Association • Centennial, Colo. • Phone: 720-554-0900, ext. 14 | ASTM Staff: Jeffrey Adkins • Phone: 610-832-9738 | Upcoming Meeting: June 23-25 • Montreal, Quebec, Canada