Guidelines for Hot-Dip Galvanizing

Galvanizing Tips, Modern Steel Construction, April 2004, discusses principals for successful hot-dip galvanizing of steel components, including:

• Symmetry: Balanced sectional shapes, such as H-sections, respond more uniformly to the thermal stresses of galvanizing and are less prone to distortion than unbalanced shapes such as C- or T-sections. Residual stresses from unbalanced forming or welding can have similar effects.
• Uniformity: Uniformity of thickness in section, of composition, and of surface character also reduce the distorting effects of thermal stresses, as well as promote a more consistent appearance of the galvanized finish.
• Cleanliness: Scale, rust, organic coatings, and other surface contaminants can interfere with the metallurgical reaction that bonds the molten zinc to the base steel.
• Access: Safe effective galvanizing depends on the free flow and draining of molten zinc running through the fabrication, on the free venting of steam, air, and vapors, and on access to appropriate lifting points.

The article also discusses relevant ASTM Standards, size limitations, and dipping techniques for oversize elements.

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American Galvanizers Association