The weight of the zinc coating is indicated by the number following the G. For example, G90 indicates that the zinc coating is 0.9 oz/ft one of the most popular galvanized steel carbon flat roll products available.
G90 is not a galvanizing specification; it is a coating thickness designation in the galvanizing specification ASTM A653. This specification is for hot-dip galvanizing steel sheet using the continuous (high-speed) galvanizing process. The designation G90 is simply a coating thickness of 0.9 oz/ft2 as specified in A653 and is equivalent to 0.45 oz/ft2 or about 0.76 mils per side (it is important to state per side because the oz/ft2 method takes into consideration the coating thickness on both sides of the steel, such as in the case of sheet steel). Some other coating thicknesses in A653 you may have heard of include G60 (0.6 oz/ft2) or G185 (1.85 oz/ft2).
ASTM A653 vs. ASTM A653 G90
ASTM refers to the American Society for Testing and Materials Standards.
A-653 is one of its branch standard numbers.
ASTM A653 is the standard specification for hot-dipped galvanized iron alloy or galvanized steel sheets.
ASTM A653 G90 refers to the ASTM A653 specification, the galvanized layer code G90 represents the meaning that the sum of the two-sided zinc coating is 0.9 oz/ft2 (the average minimum value of three points on both sides) or 0.8 oz/ft2 (the smallest single point on both sides) value).
ASTM A653 G90 refers to the galvanized steel sheet, the material grade is G90 (according to ASTM A653 standard), thickness 3.2 mm.
