ASTM F1941M-00

Standard Specification for Electrodeposited Coatings on Threaded Fasteners [Metric]

SCOPE
1.1 This specification covers application, performance and dimensional requirements for electrodeposited coatings on threaded fasteners with metric screw threads. It specifies coating thickness, supplementary chromate finishes, corrosion resistance, precautions for managing the risk of hydrogen embrittlement and hydrogen embrittlement relief for high-strength and surface-hardened fasteners. It also highlights the differences between barrel and rack plating and makes recommendations as to the applicability of each process.
The following precautionary statement pertains to the test method portion only, Section , of this specification:  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 and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 09-Jan-2000
• ICS: 21.060.01 - Fasteners in general
• ICS: 25.220.40 - Metallic coatings
• Technical Committee: F16 - Fasteners
• Drafting Committee: F16.03 - Coatings on Fasteners

Relations

• Replaced By: ASTM F1941M-05 - Standard Specification for Electrodeposited Coatings on Threaded Fasteners [Metric]
• Effective Date: 01-May-2005

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: F 1941M – 00
METRIC
Standard Specification for
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Electrodeposited Coatings on Threaded Fasteners [Metric]
This standard is issued under the fixed designation F 1941M; 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 (e) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
This specification covers the coating of steel metric screw threaded fasteners by electrodeposition.
The properties of the coatings shall conform to theASTM standards for the individual finishes listed.
Coating thickness values are based on the tolerances for M series metric threads having the
following tolerance positions: 6g and 4g6g for external threads, and 6H for internal threads. The
coating must not cause the basic thread size to be transgressed by either the internal or external
threads. The method of designating coated threads shall comply with ASME B1.13M.
With normal methods for depositing metallic coatings from aqueous solutions, there is a risk of
delayed failure due to hydrogen embrittlement for case hardened fasteners and fasteners having a
hardness 40 HRC or above.Although this risk can be managed by selecting raw materials suitable for
the application of electrodeposited coatings and by using modern methods of surface treatment and
post heat-treatment (baking), the risk of hydrogen embrittlement cannot be completely eliminated.
Therefore, the application of a metallic coating by electrodeposition is not recommended for such
fasteners.
1. Scope 2. Referenced Documents
1.1 This specification covers application, performance and 2.1 ASTM Standards:
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dimensional requirements for electrodeposited coatings on B 117 Practice for Operating Salt Spray (Fog) Apparatus
threaded fasteners with metric screw threads. It specifies B 487 Test Method for Measurement of Metal and Oxide
coating thickness, supplementary chromate finishes, corrosion Coating Thickness by Miocroscopical Examination of a
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resistance, precautions for managing the risk of hydrogen Cross Section
embrittlement and hydrogen embrittlement relief for high- B 499 Test Method for Measurement of Coating Thickness
strength and surface-hardened fasteners. It also highlights the by the Magnetic Method: Nonmagnetic Coatings on Mag-
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differences between barrel and rack plating and makes recom- netic Basis Metals
mendations as to the applicability of each process. B 504 Test Method for Measurement of Thickness of Me-
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1.2 The following precautionary statement pertains to the tallic Coatings by the Coulometric Method
test method portion only, Section 9, of this specification: This B 567 Test Method for Measurement of Coating Thickness
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standard does not purport to address all of the safety concerns, by the Beta Backscatter Method
if any, associated with its use. It is the responsibility of the user B 568 Test Method for Measurement of Coating Thickness
3
of this standard to establish appropriate safety and health by X-Ray Spectrometry
practices and determine the applicability of regulatory limita- B 633 Specification for Electrodeposited Coatings of Zinc
3
tions prior to use. on Iron and Steel
B 659 Guide for Measuring Thickness of Metallic and
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Inorganic Coatings
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This specification is under the jurisdiction of ASTM Committee F-16 on
Fasteners and is the direct responsibility of Subcommittee F16.03 on Coatings on
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Fasteners. Annual Book of ASTM Standards, Vol 03.02.
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Current edition approved Jan. 10, 2000. Published March 2000. Annual Book of ASTM Standards, Vol 02.05.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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F 1941M – 00
NOTE 1—Black dot (•) indicates test surface.
FIG. 1 Significant surfaces on Externally Threaded Fasteners
B 766 Specification for Electrodeposited Coatings of Cad- sample. However, if not designated, significant surfaces shall
3
mium be defined as those normally visible, directly or by reflection,
B 840 Specification for Electrodeposited Coatings of Zinc which are essential to the appearance or serviceability of the
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Cobalt Alloy Deposits fastener when assembled in normal position, or which can be
B 841 Specification for Electrodeposited Coatings of Zinc the source of corrosion products that deface visible surfaces on
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Nickel Alloy Deposits the assembled fastener. Figs. 1 and 2 illustrate significant
B 842 Specification for Electrodeposited Coatings of Zinc surfaces on standard externally threaded and internally
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Iron Alloy Deposits threaded fasteners.
E 376 Practice for Measuring Coating Thickness by
4. Classification
Magnetic-Field or Eddy-Current (Electro
...