Galvanizing Service

Hot-dip galvanized pipe is to make the molten metal react with the iron matrix to produce an alloy layer, thereby combining the matrix and the coating. Hot-dip galvanizing first acid washes the steel pipe to remove the iron oxide on the surface of the steel pipe. After acid washing, it is cleaned in a tank with ammonium chloride or zinc chloride aqueous solution or a mixture of ammonium chloride and zinc chloride aqueous solution, and then sent to the hot-dip galvanizing bath.

Hot-dip galvanizing has the advantages of uniform coating, strong adhesion, good corrosion resistance, and long service life. Especially in harsh environments, such as humid, rainy, acid rain, salt spray and other environments, the performance of hot-dip galvanizing is more prominent. The steel substrate and the molten plating solution undergo complex physical and chemical reactions to form a corrosion-resistant zinc-iron alloy layer with a tight structure. The alloy layer, pure zinc layer, and steel substrate are fused together. Therefore, it has strong corrosion resistance.

1. Uniformity of the coating: The steel pipe specimen shall not turn red (copper-plated color) after being immersed in the copper sulfate solution for 5 consecutive times.
2. Surface quality: The surface of galvanized steel pipe shall have a complete galvanized layer, and there shall be no black spots and bubbles that are not coated. It is allowed to have a slightly rough surface and local zinc nodules present.