2004_2016.pdf

AN AMERICA N NATIO NA L STA NDA RDASME B18.16M-2004Prevailing-Torque Type Steel MetricHex Nuts and Hex Flange NutsRevision and Consolidation of ASME B18.16.1M,B18.16.2M,and B18.16.3MREAFFIRMED 2016Intentionally left blank ASME B18.16M-2004Prevailing-Torque TypeSteel Metric Hex Nuts andHex Flange NutsRevision and Consolidation of ASME B18.16.1M,B18.16.2M,and B18.16.3MThree Park Avenue New York,NY 10016AN AMERICAN NATIONAL STANDARDDate of Issuance:May 13,2005This Standard will be revised when the Society approves the issuance of a new edition.There will beno addenda issued to this edition.ASME issues written replies to inquiries concerning interpretation of technical aspects of this Standard.In-terpretations are published on the ASME Web site under the Committee Pages at http:/www.asme.org/codesas they are issued.ASME is the registered trademark of The American Society of Mechanical Engineers.This code or standard was developed under procedures accredited as meeting the criteria for American National Stan-dards.The Standards Committee that approved the code or standard was balanced to assure that individuals from com-petent and concerned interests have had an opportunity to participate.The proposed code or standard was made avail-able for 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 respect to the validity of any patent rights asserted in connection with any itemsmentioned in this document,and does not undertake to insure anyone utilizing a standard against liability for infringe-ment of any applicable letters patent,nor assume any such liability.Users of a code or standard are expressly advisedthat determination of the validity of any such patent rights,and the risk of infringement of such rights,is entirely theirown responsibility.Participation by federal agency representative(s)or person(s)affiliated with industry is not to be interpreted as gov-ernment or industry endorsement 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 an electronic retrieval system or otherwise,without the prior written permission of the publisher.The American Society of Mechanical EngineersThree Park Avenue,New York,NY 10016-5990Copyright 2005THE AMERICAN SOCIETY OF MECHANICAL ENGINEERSAll rights reservedPrinted in U.S.A.CONTENTSForeword.ivCommittee Roster .vCorrespondence With the B18 Committee .vii1Scope .12Comparison With ISO Standards .13Reference Standards .14Terminology .25Dimensions .26Nut Designs and Property Classes .27Width Across Flats.28Thickness .29Wrenching Height .210Gaging of Hex Portion of Hex Flange Nuts .211Flange.612Bearing Surface.613Countersink.614Threads.615Material,Mechanical,and Performance Properties .616Testing .717Identification Symbols.1018Finish .1019Workmanship .1020Options .1021Inspection and Quality Assurance .1022Designation.10Figure1Load Measuring Device .8Tables1Dimensions of Prevailing-Torque Hex NutsProperty Classes 5,9,and 10 .32Dimensions of Prevailing-Torque Hex Flange NutsProperty Classes 5,9,and 10 .43Proof Loads,Clamp Loads,and Prevailing Torques for Nuts.54Examples for Test Clamp Torque Values.75Test Washers .9iiiFOREWORDAmerican National Standards Committee B18 for the standardization of bolts,screws,nuts,riv-ets,and similar fasteners was organized in March 1922 as Sectional Committee B18 under theaegis of the American Engineering Standards Committee(later the American Standards Associ-ation,the United States of America Standards Institute and,as of October 6,1969,the AmericanNational Standards Institute,Inc.)with the Society of Automotive Engineers and the AmericanSociety of Mechanical Engineers as joint sponsors.Subcommittee 16 was established in 1961 andcharged with the responsibility for technical content of standards covering prevailing-torque nuts.In 1972 the International Organization for Standardization published standards ISO 2320 andISO 2358,covering the mechanical and performance properties and dimensions of metric serieshexagon prevailing-torque type nuts,respectively.In December 1974,Committee B18 directed Subcommittee 16 to discontinue work on standardsfor inch series prevailing-torque type hex nuts and to develop standards for metric series nuts.As a result,ASME B18.16.1M-1979,ASME B18.16.2M-1979,and ASME B18.16.3M-1982 wereapproved.B18.16.3M was revised in 1998 to better meet the needs of conformance with PublicLaw 100-592.The revision defined those dimensions or characteristics which should be certifiedto assure product fit,form,and function.Other dimensions given would only be examined in theevent o