1、ASME B18.21.2M-1999(Revision of ASME B18.21.2M-1994)LOCK WASHERS(METRIC SERIES)A N A M E R I C A N N A T I O N A LS T A N D A R DASME B18.21.2M-1999(Revision of ASME B18.21.2M-1994)LOCK WASHERS(METRIC SERIES)A N A M E R I C A N N A T I O N A LS T A N D A R DB18.21.2M-1999 5/10/00 2:34 PM Page 1REAFF
2、IRMED 2014FOR CURRENT COMMITTEE PERSONNELPLEASE E-MAIL CSasme.orgIntentionally left blank AN AMERICAN NA T I O N A LS T A ND A R DLOCK WASHERS(METRIC SERIES)ASME B18.21.2M-1999(Revision of ASME B18.21.2M-1994)B18.21.2M-1999 5/10/00 2:34 PM Page 3p.107-12-01 12:02:35Unit:UCPTextfile:B18212$cpep.1Date
3、 of Issuance:January 31,2000This Standard will be revised when the Society approves the issuance ofa new edition.There will be no addenda or written interpretations of therequirements of this Standard issued to this edition.ASME is the registered trademark of The American Society of Mechanical Engin
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9、roduced in any form,in an electronic retrieval system or otherwise,without the prior written permission of the publisher.The American Society of Mechanical EngineersThree Park Avenue,New York,NY 10016-5990Copyright 2000 byTHE AMERICAN SOCIETY OF MECHANICAL ENGINEERSAll Rights ReservedPrinted in U.S.
10、A.p.312-23-99 08:19:25Unit:ufwTextfile:b18212$fwp.3FOREWORDAmerican National Standards Committee B27 for the standardization of plain and lockwashers was organized in March 1926 as Sectional Committee B27 under the aegis of theAmerican Standards Association(later the United States of America Standar
11、ds Institute and,as of October 6,1969,the American National Standards Institute,Inc.),with the Societyof Automotive Engineers and the American Society of Mechanical Engineers as jointsponsors.Since 1950,this Committee has been designated responsibility for standardizationof washers and machine rings
12、.In May of 1928,the B27 Committee established two subcommittees to carry on developmentwork:Subcommittee 11on plain washers and Subcommittee 21on lock washers.A tentativestandard for helical spring lock washers circulated for industry comment in November 1931failed to achieve acceptance and Committe
13、e activity became dormant for some years.In 1940,the B27 Committee was reorganized and Subcommittee 2 proceeded to draft aproposal covering three series of helical spring lock washers,designated light,medium,andheavy.In 1943,this proposal was amended to include the extra-heavy series washers and,fol
14、lowing approval by the B27 Committee and sponsor organizations,was accepted as anAmerican Standard under the designation ASA B27.1-1944.During the ensuing years,minor refinements to the hardness requirements and methodsof test were considered,and in December 1948,the B27 Committee accepted,in princi
15、ple,expansion of the standard to cover helical spring lock washers made from materials otherthan carbon steel and inclusion of specifications for tooth lock washers,and both helicalspring and tooth lock washer machine screw assemblies.A draft proposal incorporatingrequirements applicable to corrosio
16、n resistant steel,phosphor bronze,silicon bronze,aluminum-zinc alloy,and K-monel helical spring lock washers and the other new products wascompleted by Subcommittee 2 in September 1949.Subsequent to approval by the B27Committee and sponsors,this proposal was forwarded to the American Standards Associationand declared an American Standard on May 22,1950.During the years 1951 through 1958,Subcommittee 2 held five meetings,at which itwas agreed to extend the light and heavy series helical spring lo