Scope:

The ASTM A90 test technique establishes a standard for calculating the weight of zinc coatings on iron and steel items. Zinc coatings on iron and steel objects provide corrosion resistance. Different designations or coating classes are typically delivered in specifications for zinc-coated goods so that the buyer can select the coating weight best suited for the intended application.

Test Procedure:

In the ASTM A90 test, the zinc covering on the specimens is removed, then after cleaning the specimens with naphtha or another suitable solvent, the weights of the individual specimens are determined to the nearest 0.01 g. Each specimen is dipped in the stripping solution separately after determining the weight. The specimens are washed after stripping them by scrubbing them under running water, dipping them in hot water, and then wiping or blow-drying them.

Specimen Size : 

The specimen is created to the measurements specified, with an area of 5.08 in².

Data:

The following formula is used in the ASTM A90 test method:

C=[(W1-W2)/A]×K

where:

C is the weight [mass] of the coating,

W1 is the original weight

W2 is weight of stripped specimen,

A is the area of one surface of a sheet and

K is a constant.

Conclusion:

The ASTM A90 test technique establishes a standard for calculating the weight of zinc coatings on iron and steel items.