1、Designation: F1941 10F1941/F1941M 15Standard Specification forElectrodeposited Coatings on Threaded Fasteners (UnifiedInch Screw Threads (UN/UNR)Mechanical Fasteners, Inchand Metric1This standard is issued under the fixed designation F1941;F1941/F1941M; the number immediately following the designati
2、on indicatesthe year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of lastreapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval.INTRODUCTIONThis specification covers the coati
3、ng of steel unified inch screw threaded and metric mechanicalfasteners by electrodeposition. The properties of the coatings shall conform to theASTM standards forthe individual finishes listed.finishes. This standard shall be used in place of ASTM B633 formechanical fasteners.Coating thickness value
4、s are based on thestandard tolerances for 1Ainch and 2A external UnifiedInch Screw Threads. metric external threads. The coating must not cause the basic thread size to betransgressed by either the internal or external threads. The method of designating inch coated threadsshall comply withASME B1.1.
5、B1.1 and ISO 965-1, ISO 965-2, and ISO 965-3 for ISO metric coatedthreads.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 40 HRC or above. above 39
6、HRC. Although this risk can be managed by selecting rawmaterials suitable for the application of electrodeposited coatings and by using modern methods ofsurface treatment and post heat-treatment (baking), the risk of hydrogen embrittlement cannot becompletely eliminated. Therefore, the application o
7、f a metallic coating by electrodeposition is notrecommended for such fasteners.1. Scope*1.1 This specification covers application, performance and dimensional requirements for electrodeposited coatings on threadedfasteners with unified inch screw threads. and metric screw threads, but it may also be
8、 applied to other threaded parts andnon-threaded parts such as washers and pins. It specifies coating thickness, supplementary hexavalent chromate or non-hexavalentpassivateconversion finishes, corrosion resistance, precautions for managing the risk of hydrogen embrittlement and hydrogenembrittlemen
9、t relief for high-strength and surface-hardened fasteners. It also highlights the differences between barrel and rackplating and makes recommendations as to the applicability of each process.1.2 The values stated in inch-pound units are to be regarded as standard. No other units of measurement are i
10、ncluded in thisand SI metric units. The values stated in each system may not be exact equivalents; therefore each system shall be usedindependently of the other. Combining values from the two systems may result in non-conformance to the standard.1.3 Terms used in this specification are defined in Te
11、rminology F1789.1.4 The following precautionary statement pertains to the test 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 establis
12、h appropriate safety and health practices and determine the applicability of regulatory limitations priorto use.1 This specification is under the jurisdiction of ASTM Committee F16 on Fasteners and is the direct responsibility of Subcommittee F16.03 on Coatings on Fasteners.Current edition approved
13、Dec. 15, 2010Sept. 1, 2015. Published January 2011October 2015. Originally approved in 1998. Last previous edition approved in 20072010as F1941 07.F1941 10. DOI: 10.1520/F1941-10.10.1520/F1941_F1941M-15This document is not an ASTM standard and is intended only to provide the user of an ASTM standard
14、 an indication of what changes have been made to the previous version. Becauseit 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 versionof the standard as published by ASTM is
15、 to be considered the official document.*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 States12. Referenced Documents2.1 ASTM Standards:2B117 Practice for Operating Salt Spray
16、 (Fog) ApparatusB487 Test Method for Measurement of Metal and Oxide Coating Thickness by Microscopical Examination of Cross SectionB499 Test Method for Measurement of CoatingThicknesses by the Magnetic Method: Nonmagnetic Coatings on Magnetic BasisMetalsB504 Test Method for Measurement of Thickness
17、of Metallic Coatings by the Coulometric MethodB567 Test Method for Measurement of Coating Thickness by the Beta Backscatter MethodB568 Test Method for Measurement of Coating Thickness by X-Ray SpectrometryB659 Guide for Measuring Thickness of Metallic and Inorganic CoatingsD6492 Practice for Detecti
18、on of Hexavalent Chromium On Zinc and Zinc/Aluminum Alloy Coated SteelE376 Practice for Measuring Coating Thickness by Magnetic-Field or Eddy-Current (Electromagnetic) Testing MethodsF519 Test Method for Mechanical Hydrogen Embrittlement Evaluation of Plating/Coating Processes and Service Environmen
19、tsF606F606/F606M Test Methods for Determining the Mechanical Properties of Externally and Internally Threaded Fasteners,Washers, and Rivets (Metric) F0606_F0606M Direct Tension Indicators, and RivetsF788 Specification for Surface Discontinuities of Bolts, Screws, and Studs, Inch and Metric SeriesF14
20、70 Practice for Fastener Sampling for Specified Mechanical Properties and Performance InspectionF1624 Test Method for Measurement of Hydrogen Embrittlement Threshold in Steel by the Incremental Step Loading TechniqueF1789 Terminology for F16 Mechanical FastenersF1940 Test Method for Process Control
21、Verification to Prevent Hydrogen Embrittlement in Plated or Coated FastenersF2078 Terminology Relating to Hydrogen Embrittlement Testing2.2 ASME Standard:Standards:3B1.1 Unified Inch Screw Threads (UN and UNR Thread Form)B1.2 Gages and Gaging for Unified Inch Screw ThreadsB1.16M Gages and Gaging for
22、 Metric M Screw ThreadsB18.6.3 Machine Screws, Tapping Screws, and Metallic Drive Screws (Inch Series)2.3 National Aerospace Standard (AIA):4NASM-1312-5 Fast Test Method - Method 5: Stress Durability2.4 IFI Standard:5IFI-142 Hydrogen Embrittlement Risk Management2.5 ISO Standards:6ISO 965-1 ISO Gene
23、ral Purpose Metric Screw Threads Tolerances Part 1: Principles and Basic DataISO 965-2 ISO General Purpose Metric Screw Threads Tolerances Part 2: Limits of Sizes for General Purpose External andInternal Screw ThreadsISO 965-3 ISO General Purpose Metric Screw Threads Tolerances Part 3: Deviations fo
24、r Construction Screw ThreadsISO 4042 Electroplated Coatings3. Terminology3.1 Definitions:3.1.1 local thicknessthe mean of the thickness measurements, of which a specified number is made within a reference area.3.1.2 minimum local thicknessthe lowest local thickness value on the significant surface o
25、f a single article.3.1.1 reference areathe area within which a specified number of single measurements are required to be made.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information,
26、 refer to the standards Document Summary page on the ASTM website.3 Available from American Society of Mechanical Engineers (ASME), ASME International Headquarters, Three Park Ave., New York, NY 10016-5990, http:/www.asme.org.4 Available from Standardization Documents Order Desk, DODSSP, Bldg. 4, Se
27、ction D, 700 Robbins Ave., Philadelphia, PA 19111-5098.5 Available from Industrial Fasteners Institute (IFI), 1717 East 9th Street, Suite 1105, Cleveland, OH 441142879.6 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http:/www.ansi.org.NOT
28、E 1Black dot () indicates test surface.FIG. 1 Significant Surfaces on Externally Threaded FastenersF1941/F1941M 1523.1.2 sealantchemical with or without integral lubricant applied on the substrate which forms a composite layer with aconversion coating in order to improve chemical resistance, corrosi
29、on protection, UV resistance, etc.3.1.3 significant surfacesignificant surfaces are areas where the minimum thickness to be met shall be designated on theapplicable drawing or by the provision of a suitably marked sample. However, if not designated, significant surfaces shall bedefined as those norm
30、ally visible, directly or by reflection, which are essential to the appearance or serviceability of the fastenerwhen assembled in normal position, or which can be the source of corrosion products that deface visible surfaces on the assembledfastener. Figs. 1 and 2 illustrate significant surfaces on
31、standard externally threaded and internally threaded fasteners.fasteners andwashers.3.1.4 top coatadditional layer with or without integral lubricant applied on a substrate in order to achieve functional propertiessuch as torque-tension control, color, chemical resistance, etc.4. Classification4.1 C
32、oating MaterialThe coating material shall be selected and designated in accordance with Table 1.4.2 Coating ThicknessThe coating thickness shall be selected and designated in accordance with Table 2:.4.3 ChromateConversion FinishThe conversion finish shall be selected and designated in accordance wi
33、th Table 3. When notspecified, the hexavalent, trivalent or other chromiate hexavalent chromium, or hexavalent chromium free passivation such astrivalent chromium passivation or other non-chromium passivation finish shall be used at the option of the manufacturer and itsappearance shall be selected
34、in accordance with the designation selected in Table 3.4.3.1 Passivatefor the purpose of this specification, a conversion coating shall not contain hexavalent chromium.4.3.1.1 Trivalent Chromite Passivate FinishUnless otherwise specified, the typical appearance of the trivalent chromite finishshall
35、be transparent, colorless and shall not be subjected to the requirements of typical appearance as determined in Table 3. Inaddition, the classification code to be used shall be appended with the letter “T“ (for example, Fe/Zn 5CT, as defined in TableA1.1).4.3.1.2 Supplemental Passivate FinishUnless
36、otherwise specified, the typical appearance of the supplemental passivate finishshall be transparent, colorless and shall not be subjected to the requirements of typical appearances as determined in Table 3. Inaddition, the classification code to be used shall be appended with the letter “S” (for ex
37、ample Fe/Zn 5AS). Other colored finishesmay be specified at time of purchase. Requirements of the other colored finishes to be agreed upon at time of purchase.NOTE 1The use of supplemental passivated finishes are technically not “chromate” films and they do not contain hexavalent chromium ions, they
38、are supplemental coatings that render the active zinc surface passive and provide protection to the steel fastener.4.4 Supplemental Lubricant, Sealants or Top CoatsAdditional sealants or top coats (with or without integral lubricant) maybe chosen to increase corrosion resistance and to achieve other
39、 specific properties such as torque-tension, UV resistance, etc. Theselection of the nature of a sealant or top coat should be based on desired additional properties. When sealants or top coats arespecified, the classification code in Table 3 shall be appended by adding the letter “S” (for example F
40、e/Zn 5ANS). When specifyinga lubricant, the classification code in Table 3shall be appended with the letter “L” (for example Fe/Zn 5ANSL).NOTE 1When using a sealant or top coat, a separate conversion finish layer and/or lubricant layer may not be required to achieve the corrosionperformance or provi
41、de lubricity.4.5 Fig. 3 illustrates the basic electroplating coating systems.4.5.1 Only coating material layer(s).4.5.2 Coating material layer(s) plus conversion finish (for example Fe/Zn 5A).4.5.3 Coating material layer(s) plus conversion finish plus additional lubricant (example Fe/Zn 5ANL).4.5.4
42、Coating material layer(s) plus conversion finish plus sealant top coat (example Fe/Zn 5ANS).4.5.5 Coating material layer(s) plus conversion finish plus sealant top coat plus additional lubricant (example Fe/Zn 5ANSL).5. Ordering Information for Electroplating5.1 When ordering threaded fasteners to b
43、e coated by electrodeposition in accordance with this specification, the followinginformation shall be supplied to the electroplater:NOTE 1Black dot () indicates test surface.FIG. 2 Significant Surfaces on Internally Threaded Fasteners and WashersF1941/F1941M 1535.1.1 The desired coating, coating th
44、ickness, the chromate or passivate conversion finish, the color and appearance (ifapplicable), or the classification codes as specified in Tables 1-3. and additional sealants or top coats (for example, Fe/Zn 5Cdenotes yellow zinc plated with a minimum thickness of 0.0002 in. or 5 m for metric on sig
45、nificant surfaces.)surfaces).5.1.2 The identification of significant surfaces (optional).5.1.3 The requirement, if any, for stress relief before electroplating, in which case the stress-relief conditions must be specified.5.1.4 The requirements, if any, for hydrogen embrittlement relief by heat trea
46、tment (baking) stating the tensile strength orsurface(baking), other than as required by 6.4.1 hardness of the fasteners and/or must be specified. Requirements shall includebaking time and temperature.NOTE 2Fasteners with a specified maximum hardness of 34 HRC and below have a very low susceptibilit
47、y to hydrogen embrittlement and do notrequire baking.5.1.5 The requirements, if any, for embrittlement testing other than as required by 6.4.3 must be specified.NOTE 2Through hardened fasteners with a specified maximum hardness of 39 HRC and below have a low susceptibility to hydrogen embrittlementa
48、nd do not require baking.5.1.6 The requirements, if any, for the type of electroplating process (barrel-plating or rack-plating). See Section 10 andAppendix X1.5.1.7 The designation of inch coated thread class shall comply withASME B1.1.B1.1 and metric threads shall comply with ISO965-1, ISO 965-2 a
49、nd ISO 965-3.6. Requirements6.1 Coating RequirementsThe electrodeposited coating as ordered shall cover all surfaces and shall meet the followingrequirements:6.1.1 The coating metal deposit shall be bright or semi-bright unless otherwise specified by the purchaser, smooth, fine grained,adherent and uniform in appearance.6.1.2 The coating coated fastener shall be free of blisters, pits, nodules, roughness, cracks, unplated areas, and other defects thatwill affect the function of the coating.6.1.3 The coating shall not be stained, discolor
