ASTM A428 – Standard Test Method for Weight [Mass] of Coating on Aluminum-Coated Iron or Steel Articles
Significance and Use
3.1 This test method provides a standard method for determining the weight [mass] of aluminum coatings on iron or steel products, and for evaluating conformance of such products to a material specification under the jurisdiction of ASTM Committee A05 and its subcommittees as designated by a purchaser in a purchase order or contract.
3.1.1 This test method may be and is used by other ASTM Committees and other standards writing bodies for the purpose of conformance testing.
3.1.2 The material condition at the time of testing, sampling frequency, specimen location and orientation, reporting requirements, and other test parameters are contained in the pertinent material specification or in a general requirement specification for the particular product form.
3.1.3 A coating of aluminum on iron or steel articles provides protection against corrosion by forming a relatively inert barrier. Specifications for aluminum-coated articles frequently provide for different designations or classes of coating so that the purchaser can select the coating weight [mass] most suitable for the intended application. The heavier coating will provide greater protection against mechanical damage which may break the coating.
3.2 This test method determines the average coating weight [mass] over a specified area, from which the average thickness can be calculated. Other test methods not described herein can determine the thickness directly at point locations on the coating; in such cases, the required test method is described in that material specification or by reference to another appropriate test method standard.
1.1 This test method covers procedures for determining the weight [mass] of coating on aluminum-coated iron or steel sheets and wire, and on other aluminum-coated iron and steel articles.
1.2 Units—The final results determined by this test method shall be expressed in inch-pound units or SI units, depending on the units used in the material specification to which the results are to be compared. Certain portions of the procedure involving determination of specimen weight [mass] have traditionally been performed in SI units, and corresponding inch-pound units are not included.
1.3 For sheet products, the final results are expressed as either coating weight [mass] total both sides, or coating weight [mass] separately on each side, depending on the specified requirements.