Which of the following describes G60 and G20?

• A. Base steel grade
• B. Copper content in the coating
• C. Zinc coating thickness on galvanized steel
• D. Coating color of the zinc

Answer: (C)

G60 and G20 refer to the zinc coating thickness on galvanized steel. They’re a shorthand for how thick the zinc layer is after galvanizing, with higher numbers meaning a thicker coating and longer life in corrosive environments. This designation has nothing to do with the base steel grade, copper content in the coating, or the color of the coating. In other words, these codes are all about how much zinc is deposited on the surface, which directly affects corrosion resistance.