1、AN AMERICAN NATIONAL STANDARD ASME B18.16.6-2017(Revision of ASME B18.16.6-2014)Prevailing Torque Locknuts (Inch Series)ASME B18.16.6-2017(Revision of ASME B18.16.6-2014)PrevailingTorque Locknuts(Inch Series)AN AMERICAN NATIONAL STANDARDTwo Park Avenue New York, NY 10016 USADate of Issuance: June 19
2、, 2017This Standard will be revised when the Society approves the issuance of a new edition.ASME issues written replies to inquiries concerning interpretations of technical aspects of thisStandard. Interpretations are published on the Committee Web page and undergo.asme.org/InterpsDatabase. Periodic
3、ally certain actions of the ASME B18 Committee may bepublished as Cases. Cases are published on the ASME Web site under the B18 Committee Page atgo.asme.org/B18committee as they are issued.Errata to codes and standards may be posted on the ASME Web site under the Committee Pages toprovide correction
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5、rata are posted to a particular code or standard.This option can be found on the appropriate Committee Page after selecting “Errata” in the “PublicationInformation” section.ASME is the registered trademark of The American Society of Mechanical Engineers.This code or standard was developed under proc
6、edures accredited as meeting the criteria for American NationalStandards. The Standards Committee that approved the code or standard was balanced to assure that individuals fromcompetent and concerned interests have had an opportunity to participate. The proposed code or standard was madeavailable f
7、or public review and comment that provides an opportunity for additional public input from industry, academia,regulatory agencies, and the public-at-large.ASME does not “approve,” “rate,” or “endorse” any item, construction, proprietary device, or activity.ASME does not take any position with respec
8、t to the validity of any patent rights asserted in connection with anyitems mentioned in this document, and does not undertake to insure anyone utilizing a standard against liability forinfringement of any applicable letters patent, nor assumes any such liability. Users of a code or standard are exp
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10、sement of this code or standard.ASME accepts responsibility for only those interpretations of this document issued in accordance with the establishedASME procedures and policies, which precludes the issuance of interpretations by individuals.No part of this document may be reproduced in any form,in
11、an electronic retrieval system or otherwise,without the prior written permission of the publisher.The American Society of Mechanical EngineersTwo Park Avenue, New York, NY 10016-5990Copyright 2017 byTHE AMERICAN SOCIETY OF MECHANICAL ENGINEERSAll rights reservedPrinted in U.S.A.CONTENTSForeword ivCo
12、mmittee Roster . vCorrespondence With the B18 Committee vi1 Introduction . 12 Reference Standards . 13 Terminology . 14 Dimensions 15 Nut Designs and Property Grades . 26 Corner Fill . 27 Chamfers and Bearing Circles. 28 Countersinks 29 Threads . 210 Material, Mechanical, and Performance Properties
13、. 1111 Test Methods 1112 Grades and Manufacturing Marking . 1513 Quality Assurance 1514 Workmanship 1515 Designation . 15Tables1 Chemical Composition Requirements . 22 Hardness Requirements . 23 Style NE Nylon Insert Locknut Dimensions . 34 Style NTE Nylon Insert Locknut Dimensions 45 Style NU Nylon
14、 Insert Locknut Dimensions . 56 Style NTU Nylon Insert Locknut Dimensions 67 Style NM Nylon Insert Locknut Dimensions . 78 Style NTM Nylon Insert Locknut Dimensions . 79 Dimensions of Nylon Insert Hex Flange Nuts . 810 Dimensions of Prevailing Torque All-Metal Type Hex Nuts 911 Dimensions of Prevail
15、ing Torque All-Metal Type Hex Flange Nuts . 1012 Proof Loads, Clamp Loads, and Prevailing Torques for Coarse Thread Locknuts 1213 Proof Loads, Clamp Loads, and Prevailing Torques for Fine Thread Locknuts 1314 Proof Loads, Clamp Loads, and Prevailing Torques for 8-UN Series ThreadLocknuts . 13iiiFORE
16、WORDASME B18.16.6-2008 was balloted and approved by the B18 Standards Committee andB18 Subcommittee 16 on April 29, 2008. The proposal was submitted to the American NationalStandards Institute and designated as an American National Standard on August 25, 2008.At the B18 meeting in the fall of 2011,
17、Subcommittee 16 decided to expand this Standard toinclude all styles of locking nuts. B18.16.6 now contained dimensional and performance require-ments for nonmetallic insert and all-metal locking nuts in a variety of grades. This Standard wasintended to replace IFI-100/107, which the Industrial Fast
18、eners Institute agreed to withdraw afterthe publication of this Standard. ASME B18.16.6-2014 was balloted and approved by the B18Standards Committee and B18 Subcommittee 16 on March 12, 2014.At the B18 meeting in the spring of 2015, Subcommittee 16 decided to revise this Standardbased on several tec
19、hnical and editorial updates. Updates to this Standard include lowering theproof and clamp load values of thin nuts from 60% to 45% of regular hex nuts; harmonizingproof loads with SAE J995 2012, resulting in lower proof loads for fine and 8-UN series nuts;correcting hex height values on style NTM l
20、ocknuts; clarifying corner fill requirements; increasingthe proof load requirement for style NU locknuts; and correcting various table references.This revision was approved as an American National Standard on June 1, 2017.Suggestions for improvement of this Standard are welcome. They should be sent
21、to Secretary,B18 Committee, The American Society of Mechanical Engineers, Two Park Avenue, New York,NY 10016-5990.ivASME B18 COMMITTEEStandardization of Bolts, Nuts, Rivets, Screws,Washers, and Similar Fasteners(The following is the roster of the Committee at the time of approval of this Standard.)S
22、TANDARDS COMMITTEE OFFICERSF. J. Perry, ChairD. S. George, Vice ChairR. D. Strong, Vice ChairA. L. Guzman Rodriguez, SecretarySTANDARDS COMMITTEE PERSONNELT. Anderson, Bay BoltL. Borowski, Greenslade however, they should not contain proprietary names orinformation.viRequests that are not in the form
23、at described above may be rewritten in the appropriate formatby the Committee prior to being answered, which may inadvertently change the intent of theoriginal request.ASME procedures provide for reconsideration of any interpretation when or if additionalinformation that might affect an interpretati
24、on is available. Further, persons aggrieved by aninterpretation may appeal to the cognizant ASME Committee or Subcommittee. ASME does not“approve,” “certify,” “rate,” or “endorse” any item, construction, proprietary device, or activity.Attending Committee Meetings. The B18 Standards Committee regula
25、rly holds meetingsand/or telephone conferences that are open to the public. Persons wishing to attend any meetingand/or telephone conference should contact the Secretary of the B18 Standards Committee. FutureCommittee meeting dates and locations can be found on the Committee Page atgo.asme.org/B18co
26、mmittee.viiINTENTIONALLY LEFT BLANKviiiASME B18.16.6-2017PREVAILING TORQUE LOCKNUTS(INCH SERIES)1 INTRODUCTION1.1 ScopeThis Standard covers the complete general, dimen-sional, mechanical, and performance requirements(proof load, prevailing torque, and torque-tension) forcarbon steel, inch series nyl
27、on insert locknuts of gradesN2, N5, and N8 in styles NE (14in. to 112in.),NTE (14in. to 112in.), NU (14in. to 3 in.), NTU(14in. to 3 in.), NM (#2 to #12), NTM (#2 to #12), andhex flange (14in. to34in.). This Standard also includesall-metal hex (#4 to 112in.) and hex flange (14in. to34in.)locking nut
28、s of grades A, B, C, F, and G. These nutdesigns are designated as American National Standards.1.2 Comparison to ISO StandardsThere is no ISO inch standard for these products.2 REFERENCE STANDARDSThe following is a list of publications referenced inthis Standard. Unless otherwise specified, the refer
29、encestandard(s) shall be the most recent issue at the time oforder placement.ASME B1.1, Unified Inch Screw Threads (UN and UNRThread Form)ASME B1.3, Screw Thread Gaging Systems forAcceptability: Inch and Metric Screw Threads (UN,UNR, UNJ, M, and MJ)ASME B1.15, Unified Inch Screw Threads (UNJ ThreadF
30、orm)ASME B18.2.1, Square, Hex, Heavy Hex, and AskewHead Bolts and Hex, Heavy Hex, Hex Flange, LobedHead, and Lag Screws (Inch Series)ASME B18.12, Glossary of Terms for MechanicalFastenersASME B18.18, Quality Assurance for FastenersASME B18.21.1, Washers: Helical Spring-Lock, ToothLock, and Plain Was
31、hers (Inch Series)Publisher: The American Society of MechanicalEngineers (ASME), Two Park Avenue, New York,NY 10016-5990 (www.asme.org)ASTM F436, Standard Specification for Hardened SteelWashers1ASTM F606/F606M, Standard Test Methods forDetermining the Mechanical Properties of Externallyand Internal
32、ly Threaded Fasteners, Washers, DirectTension Indicators, and RivetsASTM F788, Standard Specification for SurfaceDiscontinuities of Bolts, Screws, and Studs, Inch andMetric SeriesASTM F812, Standard Specification for SurfaceDiscontinuities of Nuts, Inch and Metric SeriesASTM F1137, Standard Specific
33、ation for Phosphate/OilCorrosion Protective Coatings for FastenersASTM F1470, Standard Practice for Fastener Samplingfor Specified Mechanical Properties and PerformanceInspectionASTM F1941/F1941M, Standard Specification forElectrodeposited Coatings on Mechanical Fasteners,Inch and MetricPublisher: A
34、merican Society for Testing and Materials(ASTM International), 100 Barr Harbor Drive, P.O. BoxC700, West Conshohocken, PA 19428-2959(www.astm.org)IFI-101, Torque-Tension Requirements for Prevailing-Torque Type Steel Hex and Hex Flange NutsPublisher: Industrial Fasteners Institute (IFI),6363 Oak Tree
35、 Boulevard, Independence, OH 44131(www.indfast.org)SAE J409, Product Analysis Permissible Variationsfrom Specified Chemical Analysis of a Heat or Castof SteelPublisher: SAE International, 400 Commonwealth Drive,Warrendale, PA 15096-0001 (www.sae.org)3 TERMINOLOGYFor definitions of terms relating to
36、fasteners or compo-nent features thereof used in this Standard, refer toASME B18.12.4 DIMENSIONSUnless otherwise specified, all dimensions in thisStandard are inches and shall be as specified in the tablesand sections 6 through 9. All dimensions apply beforecoating.ASME B18.16.6-20175 NUT DESIGNS AN
37、D PROPERTY GRADES5.1 Nylon Insert LocknutsNylon insert locknuts are two-piece construction hexnuts and hex flange nuts that derive their prevailingtorque characteristics from a full ring of nylon material,located and retained in the nut under its top surface.These are designated in Table 1 as proper
38、ty grades N2,N5, and N8 with hardness requirements in Table 2. Theconfiguration styles are NE (Table 3), NTE (Table 4), NU(Table 5), NTU (Table 6), NM (Table 7), NTM (Table 8),and hex flange (Table 9).5.2 All-Metal LocknutsAll-metal locknuts are one-piece construction hex andhex flange nuts that der
39、ive their prevailing torque per-formance from controlled distortion of the nut threadsand/or body. Hex locknuts are designated as grades A,B, and C. The dimensions are located in Table 10. Hexflange locknuts are designated as grades F and G. Thedimensions are in Table 11. Table 1 identifies the mate
40、rialrequirements for the various grades, and Table 2 identi-fies sizes and hardness requirements for the variousgrades.6 CORNER FILLA rounding or lack of fill at the location where the hexcorners intersect with the chamfer shall be permissible,provided the width across corners is within specifiedlim
41、its in the area extending from a distance equal to17.5% of the basic thread diameter from the chamferedbearing face to 85% of the specified minimum hex height.7 CHAMFERS AND BEARING CIRCLES7.1 Chamfer Length on Bearing Side of NutsThe length of chamfer at hex corners shall be from5% to 15% of the no
42、minal thread diameter. The surfaceof the chamfer may be convex or rounded.7.2 Bearing Surface DiameterThe diameter of bearing circle on chamfered nuts andwasher-faced nuts shall be within the limits of the maxi-mum width across flats and 95% of the minimum widthacross flats.8 COUNTERSINKSUnless othe
43、rwise specified in this Standard, tappedholes shall be countersunk on the bearing faces. Themaximum countersink diameter shall be the nominalthread diameter plus 0.030 in. for38in. nominal sizenuts and smaller, and 1.08 times the nominal threaddiameter for nuts larger than38in. No part of thethreade
44、d portion shall project beyond the bearingsurface.2Table 1 Chemical Composition RequirementsC, Mn, P, S,Nut Grade Max. Min. Max. Max.N2, A 0.47 . . . 0.12 0.15Note (1) Note (2)N5, B, F 0.55 0.30 0.05 0.15Notes (3), (4) Notes (2), (4)N8, C, G 0.55 0.30 0.04 0.05Note (5)GENERAL NOTE: All values are fo
45、r ladle analysis (percent by weight)and are subject to standard variations for check analysis as given inSAE J409.NOTES:(1) Resulfurized and rephosphorized material is not subject torejection based on check analysis for sulfur.(2) If agreed between purchaser and producer, sulfur content maybe 0.23 m
46、ax.(3) Phosphorus content may be 0.13 max. for acid bessemer steelonly.(4) If agreed between purchaser and producer, sulfur content maybe 0.35 max. and phosphorus content may be 0.12 max., pro-vided that manganese content is 0.70 min.(5) If agreed between purchaser and producer, sulfur content maybe
47、 0.33 max., provided that manganese content is 1.35 min.Table 2 Hardness RequirementsNut Grade Locknut SizeNote (1) Note (2) Rockwell HardnessN2, N5, A, B, and F14112C28, max.N8, C, and G1458C24C32341 C26C34118112C26C36NOTES:(1) For grade N2 sizes over 112, the minimum hardness shall beHRB 68.(2) Fo
48、r values on sizes not listed in Table 2, agreement shall bereached between purchaser and supplier.9 THREADSThreads shall be unified thread form coarse, fine, or8 thread series (UNC, UNF, or 8-UN) Class 2B in accor-dance with ASME B1.1 or UNJ thread form (UNJC,UNJF, or UNJ8 series) either Class 2B or
49、 3B in accordancewith ASME B1.15 provided all performance require-ments of the final parts are in compliance.Inspection shall be in accordance with System 21 ofASME B1.3. Inspection shall be conducted prior to nutdeformation or nylon ring captivation.After deformation or nylon captivation, the GOthreaded plug gage must enter38in. and smaller nutsat least one-half turn, and for716-in. nuts and above onefull turn from the bearing surface side of the nut.ASME B18.16.6-2017Table 3 Style NE Nylon Insert Locknut DimensionsABCDMaximum RunoutDesignat
