ASTM_F_1941_-_F_1941M_-_15.pdf

Designation:F1941/F1941M15Standard Specification forElectrodeposited Coatings on Mechanical Fasteners,Inchand Metric1This standard is issued under the fixed designation F1941/F1941M;the number immediately following the designation indicates the yearof 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.INTRODUCTIONThis specification covers the coating of steel unified inch and metric mechanical fasteners byelectrodeposition.The properties of the coatings shall conform to the ASTM standards for theindividual finishes.This standard shall be used in place of ASTM B633 for mechanical fasteners.Coating thickness values are based on standard tolerances for inch and metric external threads.Thecoating must not cause the basic thread size to be transgressed by either the internal or externalthreads.The method of designating inch coated threads shall comply withASME B1.1 and ISO 965-1,ISO 965-2,and ISO 965-3 for ISO metric coated threads.With normal methods for depositing metallic coatings from aqueous solutions,there is a risk ofdelayed failure due to hydrogen embrittlement for case hardened fasteners and fasteners having ahardness above 39 HRC.Although this risk can be managed by selecting raw materials suitable for theapplication of electrodeposited coatings and by using modern methods of surface treatment and postheat-treatment(baking),the risk of hydrogen embrittlement cannot be completely eliminated.Therefore,the application of a metallic coating by electrodeposition is not recommended for suchfasteners.1.Scope*1.1 This specification covers application,performance anddimensional requirements for electrodeposited coatings onthreaded fasteners with unified inch and metric screw threads,but it may also be applied to other threaded parts andnon-threaded parts such as washers and pins.It specifiescoating thickness,supplementary hexavalent chromate or non-hexavalent conversion finishes,corrosion resistance,precau-tions for managing the risk of hydrogen embrittlement andhydrogen embrittlement relief for high-strength and surface-hardened fasteners.It also highlights the differences betweenbarrel and rack plating and makes recommendations as to theapplicability of each process.1.2 The values stated in inch-pound units and SI metricunits.The values stated in each system may not be exactequivalents;therefore each system shall be used independentlyof the other.Combining values from the two systems mayresult in non-conformance to the standard.1.3 Terms used in this specification are defined in Termi-nology F1789.1.4 The following precautionary statement pertains to thetest method portion only,Section 9,of this specification:Thisstandard does not purport to address all of the safety concerns,if any,associated with its use.It is the responsibility of the userof this standard to establish appropriate safety and healthpractices and determine the applicability of regulatory limita-tions prior to use.2.Referenced Documents2.1 ASTM Standards:2B117 Practice for Operating Salt Spray(Fog)ApparatusB487 Test Method for Measurement of Metal and OxideCoating Thickness by Microscopical Examination ofCross SectionB499 Test Method for Measurement of Coating Thicknessesby the Magnetic Method:Nonmagnetic Coatings onMagnetic Basis MetalsB504 Test Method for Measurement of Thickness of Metal-lic Coatings by the Coulometric Method1This specification is under the jurisdiction of ASTM Committee F16 onFasteners and is the direct responsibility of Subcommittee F16.03 on Coatings onFasteners.Current edition approved Sept.1,2015.Published October 2015.Originallyapproved in 1998.Last previous edition approved in 2010 as F1941 10.DOI:10.1520/F1941_F1941M-152For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 B567 Test Method for Measurement of Coating Thicknessby the Beta Backscatter MethodB568 Test Method for Measurement of Coating Thicknessby X-Ray SpectrometryB659 Guide for Measuring Thickness of Metallic and Inor-ganic CoatingsD6492 Practice for Detection of Hexavalent Chromium OnZinc and Zinc/Aluminum Alloy Coated SteelE376 Practice for Measuring Coating Thickness byMagnetic-Field or Eddy-Current(Electromagnetic)Test-ing MethodsF519 Test Method for Mechanical Hydrogen EmbrittlementEvaluation of Plating/Coating Processes and Service En-vironmentsF606/F606M Test Methods for Determining the MechanicalPropertiesofExternallyandInternally ThreadedFasteners,Washers,Direct Tension Indicators,and RivetsF788 Specification for Surface Disco