ASTM B633-23 PDF

Full title and description

ASTM B633-23 — Standard Specification for Electrodeposited Coatings of Zinc on Iron and Steel. This specification establishes material and process requirements for electrodeposited zinc coatings applied to iron or steel articles to provide corrosion protection; it describes thickness classes, supplementary finishes, pre- and post‑plating treatments, sampling and test requirements, and limits and exclusions for certain substrates and processes.

Abstract

Specifies requirements for electrodeposited zinc coatings on iron and steel parts intended for corrosion protection. Covers required surface preparation, options for passivation/supplementary finishes (including non‑chromate options added in the 2023 revision), four standard coating-thickness classes, sampling and testing for appearance, thickness, adhesion and corrosion resistance, and measures to reduce the risk of hydrogen embrittlement. It excludes continuous zinc coating processes for wire and sheet and advises alternative standards for those products.

General information

• Status: Active standard.
• Publication date: January 1, 2023 (current edition approved January 9, 2023).
• Publisher: ASTM International (Committee B08, Subcommittee B08.06).
• ICS / categories: 25.220.40 — Metallic coatings; plating and corrosion protection.
• Edition / version: B633‑23 (2023 edition).
• Number of pages: 8 pages (current edition).

Scope

This specification covers material and process requirements for electrodeposited zinc coatings applied to iron or steel articles for corrosion protection. It details coating thickness classes, acceptable supplementary finishes (including newer non‑chromate passivates added in the 2023 revision), requirements for pre‑plating cleaning and treatments to mitigate hydrogen embrittlement, testing and acceptance criteria, and exclusions such as continuous coating processes for wire and sheet and plating of very high‑strength steels. The standard is intended as a purchaser/specifier document; users are encouraged to consult referenced standards and appendices for testing methods and additional guidance.

Key topics and requirements

• Four standard as‑plated coating thickness classes with specified minimum coating mass/weight and thickness criteria.
• Supplementary finishes/passivates options (including non‑chromate types introduced to address RoHS and hexavalent chromium reduction); specified workmanship and luster requirements.
• Pre‑ and post‑plating surface preparation and treatments to reduce hydrogen embrittlement risk and ensure adhesion.
• Sampling, preparation and specified test methods for thickness, adhesion, corrosion resistance (salt spray and other tests), and appearance.
• Explicit exclusions and limits — not intended for continuous electrodeposited zinc on wire or sheet, and not recommended for high‑strength steels above specified tensile limits.
• Guidance calling out related standards (for example, salt spray testing, electroplated sheet specifications, and fastener plating standards) to be used in conjunction with B633 where applicable.

Typical use and users

Used by design engineers, corrosion and materials engineers, plating shop operators, fastener manufacturers, procurement/specification authors, quality and inspection laboratories, and regulatory or defense agencies specifying corrosion protection for iron and steel components. Purchasers specify B633 when ordering electrodeposited zinc coatings for parts that require controlled thickness, passivation type, and demonstrable corrosion resistance. The standard is also used by test labs to verify plating conformance.

Related standards

B633 references and is commonly used with other standards such as ASTM B117 (salt spray testing), ASTM A591/A591M (electrolytic zinc‑coated sheet where applicable), ASTM F1941/F1941M (zinc electroplating for mechanical fasteners), ISO/TR 20491 (hydrogen embrittlement fundamentals), and other ASTM practices for preparation and testing of steel for electroplating. Users are advised to consult these documents for test methods and product‑specific requirements.

Keywords

electrodeposited zinc, zinc plating, metallic coatings, passivate, chromate, non‑chromate passivate, corrosion protection, hydrogen embrittlement, coating thickness, salt spray, electroplating, fasteners.

FAQ

Q: What is this standard?

A: ASTM B633-23 is the 2023 edition of the ASTM specification that establishes requirements for electrodeposited zinc coatings applied to iron and steel for corrosion protection.

Q: What does it cover?

A: It covers surface preparation, coating thickness classes, permitted supplementary finishes (including non‑chromate options), testing and acceptance criteria for appearance, adhesion and corrosion resistance, and process/material exclusions (for example, continuous coating of wire and sheet and plating of very high‑strength steels).

Q: Who typically uses it?

A: Design and corrosion engineers, plating shops, fastener and component manufacturers, procurement/spec writers, and testing/inspection laboratories use B633 to specify and verify electrodeposited zinc coatings.

Q: Is it current or superseded?

A: It is current (active) as the 2023 edition (B633‑23). It replaces earlier editions such as B633‑19. The document was approved in early January 2023.

Q: Is it part of a series?

A: B633 is part of ASTM Committee B08's body of standards on metallic and inorganic coatings (Book of Standards volume covering soft metals and plating). It is frequently used alongside related ASTM specifications and test practices covering plating processes and corrosion testing.

Q: What are the key keywords?

A: electrodeposited zinc, zinc plating, passivate, chromate/non‑chromate finish, corrosion protection, hydrogen embrittlement, coating thickness, salt spray testing.