This standard specifies technical requirements and test methods of electroplated coatings of zinc on iron or steel. This standard is applicable to electroplated coatings of zinc for the protection of iron and steel against corrosion under various service conditions.
This standard is not applicable to electroplated coatings of zinc on iron and steel sheet, strip and wire in the unfabricated form, on steel close-coiled springs and for other than protective or decorative purposes.
2 Normative References
The following documents contain provisions which, through reference in this text, constitute provisions of this standard. At the time of publication, all editions indicated are valid. All standards are subject to revision, and all parties of agreements based on this standard shall discuss the possibility of applying the updated edition of the following standards.
GB/T 4955-1997 "Metallic Coatings-Measurement of Coating Thickness-Coulometric Method by Anodic Dissolution" (neq ISO 2177:1985)
GB/T 4956-85 "Non-magnetic Coatings on Magnetic Substrates-Measurement of Coating Thickness-Magnetic Method" (eqv ISO 2178:1982)
GB 5267-85 "Electroplated Coatings on Threaded Fasteners"
GB/T 6462-86 "Metallic and Oxide Coatings-Measurement of Coating Thickness-Microscopical Method" (eqv ISO 1463:1982)
GB/T 9793-1997 "Metallic and Other Inorganic Coatings-Thermal Spraying-Zinc, Aluminium and Their Alloys" (neq ISO 2063:1973)
GB 9800-88 "Chromate Conversion Coatings on Electroplated Zinc and Cadmium Coatings" (eqv ISO 4520:1981)
GB 11378-89 "Metallic Coatings-Measurement of Coating Thickness-Profilometric Method" (eqv ISO 4518:1980)
GB/T 12334-90 "Metallic and Other Inorganic Coatings-Definitions and Conventions Concerning the Measurement of Thickness" (eqv ISO 2064:1980)
GB 12609-90 "Electrodeposited Metallic Coatings and Related Finishes-Sampling Procedures for Inspection by Attributes" (eqv ISO 4519:1980)
GB/T 13912-92 "Metallic Coatings-Hot Dip Galvanized Coatings on Fabricated Ferrous Products-Specification" (neq ISO 1461:1973)
3 Definitions
For the purposes of this standard, the following definitions apply.
3.1 Significant surface
The part of the article covered or to be covered by the coating and for which the coating is essential for appearance and/or serviceability.
3.2 Local thickness
The mean of the thickness measurements, of which a specified number is made within a reference area.
3.3 Minimum local thickness
The lowest value of the local thicknesses found on the significant surface of a single article, which is also called as minimum thickness.
4 Basis Metal
This standard does not specify requirements for the surface condition of the basis metal before electroplating with zinc, but agreement should preferably be reached between the interested parties that the surface finish of the basis metal is not too rough to prevent the appearance and/or the serviceability of the zinc coating from being satisfactory.
