This specification establishes the requirements for electrodeposited zinc coatings applied to iron or steel articles for corrosion protection purposes. Electrodeposited zinc-coated steel wires or sheets are not covered here. The coatings shall be provided in four standard thickness classes in the as-plated condition or with one of three types of supplementary finishes. The surfaces of the articles shall under go pre-plating basis metal cleaning, pre- and post-coating treatment for reducing the risk of hydrogen embrittlement, and reactivation and supplementary treatments. Coatings should be sampled, prepared, tested and conform accordingly to specified requirements as to appearance (luster and workmanship), thickness, adhesion, corrosion resistance, and hydrogen embrittlement.

1.1 This specification covers material and process requirements for electrodeposited zinc coatings applied to iron or steel articles to protect them from corrosion.

1.2 This specification is not intended to provide the design activity with all the background needed to properly specify their zinc coating requirements. The users of Specification B633 are encouraged to review this specification in its entirety including the appendices, and access the supplementary papers, other standards, and published literature referenced herein and within other related references.

1.3 The coatings are provided in four standard thickness classes (4.1), in the as-plated condition or with one of five types of supplementary finishes (4.2).

1.4 High strength metals, including high strength steels having a tensile strength greater than 1700 MPa (247 ksi, 46 HRC) should not be zinc electroplated in accordance with this specification.

1.5 It does not cover continuous processes for electrodeposited zinc coated steel wire or sheets (see Specification A591/A591M for sheets).

1.6 For zinc electroplating of mechanical fasteners, the purchaser is encouraged to consider Specification F1941/F1941M.

1.7 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.8 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.9 This standard has been revised to address RoHS requirements that seek to limit the exposure of workers and the public from exposure to toxic metals. Additional types V and VI have been added to permit non-chromate passivate treatments to be used in replacement of hexavalent chromium.

1.10 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.