ASTM A123/A123M Requirements -2
The time to first maintenance of hot-dip galvanized steel is directly proportional to the thickness of the zinc coating. With all other variables held constant, the thicker the zinc coating, the longer the life of the steel. The aim of the finish and appearance requirements is to ensure there are no problem areas deficient of zinc or with surface defects that interfere with the intended use of the product. In addition, the coating should have a strong adherence throughout the service of the hot-dip galvanized steel.