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ASTM B633-2019 pdf free download

ASTM B633-2019 pdf free download.Standard Specification for Electrodeposited Coatings of Zinc on lron and Steel
1. Scope
1.1 This specification covers material and process require- ments for electrodeposited zinc coatings applied to iron or steel articles to protect them from corrosion. 1.2 This specifcation 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 electrodepos- ited 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/ F194 IM.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 appro- priate safety, health, and environmental practices and deter- mine the applicability of regulatory limitations prior to use. 1.9 This standard has been revised to address RoHS re- quirements 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 accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
6. Materials and Manufacture
6.1 The coatings shall be non-alloyed zinc produced by electrodeposition. 6.2 Defects in the surface of the basis metal, such as scratches, porosity, pits, inclusions, cracks, roll marks, and die marks may adversely affect the appearance and performance of coatings applied thereto despite the observance of the best electroplating practices. Accordingly, the electroplater’s re- sponsibility for defects in the coating resulting from such conditions shall be waived, except when they are the prime contractor supplying electroplated parts. In this event, the basis metal shall be subjected to such polishing or buffing operations as are necessary to yield deposits with the desired final luster and appearance. To minimize problems of this sort, the specifications covering the basis material on the item to be electroplated shall contain appropriate limitations to such basis metal conditions. 6.3 Cleaning of Basis Metal- _Proper preparatory proce- dures and thorough cleaning of the basis metal are essential to ensure satisfactory adhesion and corrosion resistance perfor- mance of the coating. It is recommended that the following appropriate recommended practices and guides be used: B 183, B242, B254, B320, and B322. 6.4 Pretreatment of lron or Steel for the Purpose of Reduc- ing the Risk of Hydrogen Embrittlement- -Steel parts having an ultimate tensile strength greater than 1000 MPa (31 HRC) that contain tensile stresses caused by cold forming or cold straight- ening which have not been heat treated after the cold forming process, shall be heat treated for stress relief to reduce the risk of hydrogen embrittlement in the part before clean and elctroplate processes. If these heat treatments are not required, the purchaser shall specify in the ordering information their exception (5.2.6).

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