ASTM F1941/F1941M-16 (2025) PDF

Full title and description

ASTM F1941/F1941M-16 (reapproved 2025) — Standard Specification for Electrodeposited Coatings on Mechanical Fasteners, Inch and Metric. This specification sets application, performance and dimensional requirements for electrodeposited metallic coatings applied to threaded fasteners (inch and metric) and related small parts, including required coating thicknesses, acceptable conversion/chromate finishes, corrosion resistance, and controls for hydrogen embrittlement risk.

Abstract

This specification covers electrodeposited coatings on threaded fasteners and similar parts, specifying coating materials and thickness, allowable chromate or non-hexavalent conversion finishes, corrosion-resistance requirements, and measures for preventing and relieving hydrogen embrittlement in high‑strength and surface‑hardened fasteners. It also differentiates barrel and rack plating practices and provides recommendations for applicability of each process.

General information

• Status: Reapproved / current (F1941/F1941M-16 reapproved in 2025).
• Publication date: Reapproval recorded 1 January 2025 (original issuance: December 1, 2016).
• Publisher: ASTM International.
• ICS / categories: 21.060.01 (Fasteners in general); 25.220.40 (Metallic coatings).
• Edition / version: F1941/F1941M-16 (reapproved 2025).
• Number of pages: 14.

Scope

The standard applies to electrodeposited metallic coatings on threaded fasteners with unified inch and metric screw threads and may be applied to related non‑threaded parts (washers, pins). It specifies deposit characteristics (appearance, adhesion, freedom from defects), minimum and typical thicknesses for classification codes, allowable chromate or trivalent conversion finishes, corrosion‑resistance acceptance criteria, and mandatory precautions and procedures for managing hydrogen embrittlement (including when baking/relief is required). The specification states that SI and inch‑pound values are to be treated independently.

Key topics and requirements

• Classification of coating types and designation codes (material, thickness, chromate/passivate finish).
• Minimum coating thickness requirements and deposition tolerances for barrel and rack plating.
• Appearance and adhesion requirements: deposits must be bright or semibright, smooth, adherent and free of pits, nodules, blisters and unplated areas.
• Corrosion resistance acceptance criteria (accelerated tests and performance classes).
• Controls and mandatory actions on hydrogen embrittlement: risk assessment, bake/relief conditions for fasteners ≥ specified hardness, and reference to process qualification and test methods.
• Restriction and testing for hexavalent chromium where non‑hexavalent finishes are specified.
• Guidance on selection of barrel vs. rack plating depending on part size and required thickness.

Typical use and users

Used by fastener manufacturers, electroplaters, OEM procurement and quality engineers, and design/specification teams in automotive, aerospace, heavy equipment, construction, electronics and general manufacturing where coated fasteners are required. Also used by inspection and testing laboratories that verify coating thickness, appearance, corrosion performance and embrittlement controls.

Related standards

References and related documents commonly cited with this specification include ASTM Terminology F1789 (definitions), Test Methods and Practices referenced for embrittlement and corrosion assessment (for example F1940 and other committee F16 test methods), and other ASTM fastener/coating standards and specifications governing measurement, mechanical testing and surface finishes.

Keywords

electrodeposited coating, zinc, chromate, trivalent passivate, corrosion resistance, hydrogen embrittlement, plating, fasteners, coating thickness, barrel plating, rack plating.

FAQ

Q: What is this standard?

A: ASTM F1941/F1941M-16 (reapproved 2025) is a specification that defines requirements for electrodeposited metallic coatings on mechanical fasteners (inch and metric) including coating type, thickness, finish, corrosion performance and embrittlement controls.

Q: What does it cover?

A: It covers application and performance criteria for electroplated coatings on threaded fasteners and similar parts, acceptable appearances and defects, minimum thicknesses and classification codes, permitted chromate/convertive finishes, corrosion resistance criteria, and procedures to manage hydrogen embrittlement risk (including when baking is required).

Q: Who typically uses it?

A: Fastener manufacturers, electroplating vendors, OEMs specifying coated fasteners, procurement and quality personnel, and test/inspection labs responsible for coating verification and embrittlement testing.

Q: Is it current or superseded?

A: The designation F1941/F1941M-16 indicates the 2016 issue; the document was reapproved/reaffirmed in 2025 (designation shown as F1941/F1941M-16(2025)), and is listed as the current/reapproved version. Check with ASTM or the purchaser for the latest status before placing contractual requirements.

Q: Is it part of a series?

A: It is part of ASTM Committee F16 work on fasteners and is commonly used alongside other F16 standards and test methods (for example Terminology F1789 and embrittlement/corrosion test methods referenced in the standard).

Q: What are the key keywords?

A: Electrodeposited coating, fasteners, zinc plating, chromate, trivalent passivate, hydrogen embrittlement, coating thickness, barrel plating, rack plating, corrosion resistance.