The Difference in Appearance Between Hot-Dip Galvanized and Cold-Dip Galvanized Coatings

The cold galvanized outer surface is smooth and bright. The electroplated layer after the colored passivation process will appear yellow-green, while the electroplated layer after the white passivation process will present a light blue shade. Generally, the ends of cold galvanized steel pipes only have a small amount of zinc coating, and there is no galvanized layer further inside.

The hot-dipped galvanized surface is rough, darker in color, generally silver-white, featuring watermarks and droplet-like lumps due to the manufacturing process. The surface is non-reflective and does not emit light. Both the interior and exterior of the hot-dipped galvanized steel pipes are fully coated with zinc.