ASME_B18.2.4.6M-2010.pdf

AN AMERICAN NATIO NAL STANDARD ASME B18.2.4.6M-2010Revision of ANSI B18.2.4.6M-1979(R2003)Metric Heavy Hex NutsINTENTIONALLY LEFT BLANKASME B18.2.4.6M-2010Revision of ANSI B18.2.4.6M-1979(R2003)Metric HeavyHex NutsAN AMERICAN NATIONAL STANDARDDate of Issuance:March 31,2010This Standard will be revised when the Society approves the issuance of a new edition.There willbe no addenda issued to this edition.ASME issues written replies to inquiries concerning interpretations of technical aspects of thisStandard.Periodically certain actions of the ASME B18 Committee may be published as Cases.Cases and interpretations are published on the ASME Web site under the Committee Pages athttp:/cstools.asme.org as 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 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 forpublic review andcomment thatprovides an opportunityfor additional publicinput 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 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 expresslyadvised that determination of the validity of any such patent rights,and the risk of infringement of such rights,isentirely their own responsibility.Participation by federal agency representative(s)or person(s)affiliated with industry is not to be interpreted asgovernment 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 2010 byTHE AMERICAN SOCIETY OF MECHANICAL ENGINEERSAll rights reservedPrinted in U.S.A.w w w.b z f x w.c o mCONTENTSForeword.ivCommittee Roster.vCorrespondence With the B18 Committee.vii1Scope.12Comparison With ISO Standards.13Referenced Standards.14Terminology.15Dimensions.16Width Across Flats.17Thickness.18Tops and Bearing Surfaces.19Corner Fill.210 True Position of Hexagon to the Tapped Hole.211 Countersink.212 Threads.213 Material and Mechanical Properties.214 Finish.215 Identification Symbols.216 Inspection and Quality Assurance.217 Designation.218 Workmanship.2Table1Dimensions of Heavy Hex Nuts.3Nonmandatory AppendixAGeneral Dimension Requirements From ISO 4775.5iiiw w w.b z f x w.c o mFOREWORDThe B18 American National Standards Committee for the standardization of bolts,screws,nuts,rivets,and similar fasteners was organized in March 1922,as Sectional Committee B18 underthe aegis of the American Engineering Standards Committee(later the American StandardsAssociation,then the United States of America Standards Institute,and as of October 6,1969,the American National Standards Institute,Inc.),with the Society of Automotive Engineersand the American Society of Mechanical Engineers as joint sponsors.B18 Subcommittee 2 wassubsequently established and charged with the responsibility for technical content of standardscovering wrench head bolts and nuts.At its meeting on December 4,1974,the B18 Committee authorized preparation of a series ofstandards for metric fasteners.Subcommittee 2 was assigned responsibility for developing stan-dards for metric hex bolts,screws,and nuts.At a meeting on September 22,1976,Subcommittee 2 organized the contents of a standardcovering six different styles of hex nuts.Actual drafting was postponed until ISO/TC2 couldreach final decisions relating to basic dimensions and characteristics of hex bolts,screws,andnuts.At ISO/TC2 meetings held in April 1977,final actions were taken.The B18 Committeeaffirmed the TC2 decisions at a metting on June 29,1977,and drafting of this Standard wasstarted.In February 1978,the B18 Committee established a cooperative program with the Departmentof Defense to draft American National Standards for metric fasteners in such a way that theycould be used directly by the Government for procurement purposes.The Department of Defenserequested that each of the six nut products be covered in separate standards,and Subcommittee2 accepted this approach at its meeting on June 27,1978.This Stand