Visual Observations for Finish and Appearance
The image to the right shows products with connected galvanized pieces that have different appearances. The appearances of these pieces differ greatly from one another due to the steel chemistry of the different sections of the parts; however, all of these products continue to have an equal amount of corrosion resistance throughout and meet the specification.
A visually dull and shiny coating on a product can also be the result of a different cooling rate. In the image to the left, the outer edges of the product were cooled rapidly, allowing a free zinc layer to form on top of the inter-metallic layers. As the product weathers, the differences in appearance will become less noticeable and the overall color will turn a uniform, dull gray.
The fabrication and processing of the steel can also create a bright or dull appearance in galvanized products. The top rail in the image to the right has a winding pattern of dull gray areas corresponding to the process used during the making of the tube. The stresses in the steel from processing affect the inter-metallic formation and can result in this striped look. The corrosion protection is not affected and these parts meet the specification.
© 2020 American Galvanizers Association. The material provided herein has been developed to provide accurate and authoritative information about after-fabrication hot-dip galvanized steel. This material provides general information only and is not intended as a substitute for competent professional examination and verification as to suitability and applicability. The information provided herein is not intended as a representation or warranty on the part of the AGA. Anyone making use of this information assumes all liability arising from such use.