ASTM B633-23

Standard Specification for Electrodeposited Coatings of Zinc on Iron and Steel

ABSTRACT
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.
SCOPE
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.

General Information

• Status: Published
• Publication Date: 31-Dec-2022
• ICS: 25.220.40 - Metallic coatings
• Technical Committee: B08 - Metallic and Inorganic Coatings
• Drafting Committee: B08.06 - Soft Metals

Standards Content (Sample)

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.
Designation:B633 −23
Standard Specification for
1
Electrodeposited Coatings of Zinc on Iron and Steel
This standard is issued under the fixed designation B633; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
INTRODUCTION
This specification provides a standard to order an electrodeposited zinc coating that mitigates
corrosion of iron and steel articles in order to extend the service life of parts. The service life is
reduced when such a coating stops protecting the iron or steel substrate resulting in corrosion of the
substrate.
The pretreatment and plating process can introduce hydrogen that can cause internal hydrogen
embrittlement in high strength steels causing loss of strength and ductility. It is generally agreed that
steels below 1200 MPa are not susceptible to such embrittlement.
1. Scope* 1.7 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this
1.1 This specification covers material and process require-
standard.
mentsforelectrodepositedzinccoatingsappliedtoironorsteel
1.8 This standard does not purport to address all of the
articles to protect them from corrosion.
safety concerns, if any, associated with its use. It is the
1.2 This specification is not intended to provide the design
responsibility of the user of this standard to establish appro-
activity with all the background needed to properly specify
priate safety, health, and environmental practices and deter-
their zinc coating requirements. The users of Specification
mine the applicability of regulatory limitations prior to use.
B633 are encouraged to review this specification in its entirety
1.9 This standard has been revised to address RoHS re-
includingtheappendices,andaccessthesupplementarypapers,
quirements that seek to limit the exposure of workers and the
other standards, and published literature referenced herein and
public from exposure to toxic metals.Additional types Vand VI
within other related references.
have been added to permit non-chromate passivate treatments
1.3 The coatings are provided in four standard thickness
to be used in replacement of hexavalent chromium.
classes (4.1), in the as-plated condition or with one of five
1.10 This international standard was developed in accor-
types of supplementary finishes (4.2).
dance with internationally recognized principles on standard-
1.4 High strength metals, including high strength steels
ization established in the Decision on Principles for the
having a tensile strength greater than 1700 MPa (247 ksi,
Development of International Standards, Guides and Recom-
46 HRC) should not be zinc electroplated in accordance with
mendations issued by the World Trade Organization Technical
this specification.
Barriers to Trade (TBT) Committee.
1.5 It does not cover continuous processes for electrodepos-
2. Referenced Documents
ited zinc coated steel wire or sheets (see Specification A591/
2
2.1 ASTM Standards:
A591M for sheets).
A591/A591M Specification for Steel Sheet, Electrolytic
1.6 For zinc electroplating of mechanical fasteners, the
Zinc-Coated, for Light Coating Weight [Mass] Applica-
purchaser is encouraged to consider Specification F1941/
3
tions (Withdrawn 2005)
F1941M.
B117 Practice for Operating Salt Spray (Fog) Apparatus
1 2
This specification is under the jurisdiction of ASTM Committee B08 on For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Metallic and Inorganic Coatings and is the direct responsibility of Subcommittee contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
B08.06 on Soft Metals. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Jan. 1, 2023. Published January 2023. Originally the ASTM website.
3
approved in 1978. Last previous edition approved in 2019 as B633 – 19. DOI: The last approved version of this historical standard is referenced on
10.1520/B0633-23. www.astm.org.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
B633−23
5
B183 Practice for Preparation of Low-Carbon Steel for 2.3 ISO Standard:
Electroplating ISO/TR 20491 Fundamentals of Hydrogen Embrittlement in
Steel Faste
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: B633 − 19 B633 − 23
Standard Specification for
1
Electrodeposited Coatings of Zinc on Iron and Steel
This standard is issued under the fixed designation B633; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
INTRODUCTION
This specification provides a standard to order an electrodeposited zinc coating that mitigates
corrosion of iron and steel articles in order to extend the service life of parts. The service life is
reduced when such a coating stops protecting the iron or steel substrate resulting in corrosion of the
substrate.
The pretreatment and plating process can introduce hydrogen that can cause internal hydrogen
embrittlement in high strength steels causing loss of strength and ductility. It is generally agreed that
steels below 1200 MPa are not susceptible to such embrittlement.
1. Scope*
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
This specification is under the jurisdiction of ASTM Committee B08 on Metallic and Inorganic Coatings and is the direct responsibility of Subcommittee B08.06 on
Soft Metals.
Current edition approved March 1, 2019Jan. 1, 2023. Published March 2019January 2023. Originally approved in 1978. Last previous edition approved in 20152019 as
B633 – 15.B633 – 19. DOI: 10.1520/B0633-19.10.1520/B0633-23.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
B633 − 23
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.
2. Referenced Documents
2
2.1 ASTM Standards:
A591/A591M Specification for Steel Sheet, Electrolytic Zinc-Coated, for Light Coating Weight [Mass] Applications (Withdrawn
3
2005)
B117 Practice for Operating Salt Spray (Fog) Apparatus
B183 Practice for Preparation of Low-Carbon Steel for Electroplating
B201 Practice for Testing Chromate Coatings on Zinc and Cadmium Surfaces
B242 Guide for Preparation of High-Carbon Steel for Electroplating
B254 Practice for Preparation of and Electroplating on Stainless Steel
B320 Practice for Pr
...