1、AN AMERICAN NATIONAL STANDARDASME B18.2.6-2010(Revision of ASME B18.2.6-2006)Fasteners for Use in Structural ApplicationsINTENTIONALLY LEFT BLANKASME B18.2.6-2010(Revision of ASME B18.2.6-2006)Fasteners forUse in StructuralApplicationsAN AMERICAN NATIONAL STANDARDThree Park Avenue New York, NY 10016
2、 USADate of Issuance: August 20, 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 ac
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10、TENTSForeword ivCommittee Roster . viCorrespondence With the B18 Committee vii1 Introductory Notes 12 Heavy Hex Structural Bolts: ASTM A 325 and ASTM A 490. 23 Heavy Hex Nuts: ASTM A 563 and ASTM A 194 . 54 Hardened Steel Washers. 75 Compressible Washer-Type Direct Tension Indicators 106 Twist-Off-T
11、ype Tension Control Structural Bolts: Heavy Hex and Round:ASTM F 1852 and ASTM F 2280 . 10Figure1 Groove Diameter 13Tables1 Dimensions of Heavy Hex Structural Bolts . 22 Maximum Grip Gaging Lengths and Minimum Body Lengths for Heavy HexStructural Bolts 43 Dimensions of Heavy Hex Nuts for Use With St
12、ructural Bolts . 64 Dimensions for Hardened Steel Circular and Circular Clipped Washers . 85 Dimensions of Hardened Beveled Washers With Slope or Taper in Thickness 1:6 . 96 Dimensions for Compressible Washer-Type Direct Tension Indicators 117 Dimensions of Twist-Off-Type Tension Control Structural
13、Bolts: Heavy Hex Headand Round Head Configurations 12iiiFOREWORDThe B18 Standards Committee for the standardization of bolts, screws, nuts, rivets, and similarfasteners was organized in March 1922 as the B18 Sectional Committee under the aegis of theAmerican Engineering Standards Committee (later th
14、e American Standards Association, thentheUnitedStatesofAmericaStandardsInstituteand,asofOctober6,1969,theAmericanNationalStandards Institute, Inc.), with the Society of Automotive Engineers and the American Societyof Mechanical Engineers as joint sponsors. B18 Subcommittee 2 was subsequently establi
15、shedand charged with the responsibility for technical content of standards covering wrench headbolts and nuts.Subcommittee 2, after appraisal of the requirements of industry, developed a proposed standardseries of bolt head and nut dimensions. This proposal was finally approved and designated aTenta
16、tive American Standard in February 1927.A first revision of the document was designated as an American Standard in March 1933, andwas followed by a second revision, which was granted approval as an American Standard inJanuary 1941.Following reorganization of the B18 Committee in 1947, Subcommittee 2
17、 was asked to expandthe Standard on head proportions into a complete product standard. A proposal covering squareand hexagon head bolts and nuts, hexagon head cap screws, and automotive hexagon head boltswas prepared and submitted to the B18 Committee in April 1950. While this draft was underconside
18、ration, the B18 Committee received a proposal from the British Standards Institutionfor unification of dimensions on products incorporating unified screw threads. The Committeewelcomed the opportunity of discussing the proposals and an American-British-CanadianConference was held in New York, June 1
19、 and 2, 1950.It was agreed in the Conference that the essentials of unification could be accomplished byselection of mutually satisfactory across-the-flats dimensions, since this would permit the use ofthe same wrenches and because other features would rarely affect interchangeability. After duecons
20、ideration, suitable existing across-the-flats dimensions were selected for the hexagonproducts.In its meeting on October 13, 1950, Subcommittee 2 agreed to incorporate in the proposedstandard the conference recommendations on14in. hexagon head bolts,58in. hexagon head capscrews and automotive hexago
21、n head bolts,516in. and38in. regular hexagon and square nuts,and716in.lightandregularhexagonandsquarenuts.AtasubsequentmeetingofSubcommittee2,further changes were adopted in order to combine the light and regular series of nuts and tocombine the automotive hexagon head bolt, hexagon head cap screw,
22、and regular hexagon headclose tolerance bolt.In view of the progress made in the United States and the urgency of standardization formutual defense, the British Standards Institution sponsored a second Conference in London inApril 1951 to complete the unification of certain hexagon bolts and nuts.At
23、ameetingonJune8,1951,Subcommittee2reaffirmeditsacceptanceoftheunifieddimensions,which corresponded with those in the March 1951 draft, but attempted to select better nomencla-ture for the unified products. A final draft incorporating the nomenclature Finished HexagonBolts and Nuts and containing num
24、erous editorial changes was submitted for letter ballot inSeptember 1951. Following approval by the B18 Committee and the sponsors, the proposal waspresented to the American Standards Association for approval and designation as an AmericanStandard. This was granted on March 24, 1952.RecognizingtheSt
25、andardwasinneedofadditionalrefinements,Subcommittee2beganimmedi-ately to revise it: removing inconsistencies with respect to fillets, improving the length toleranceson heavy hexagon bolts, and incorporating numerous other corrections and clarifications. Themost noteworthy editorial change was a deci
26、sion to combine the coverage for hexagon cap screwsand square head set screws from the B18.2 Standard with the coverage for slotted head capscrews and slotted headless set screws from the B18.6 Standard and publish them in a separateivdocument. The requirements for the unified hexagon cap screws and
27、 finished hexagon bolts beingidenticalintheoverlappingsizes,thisdatawouldnowbeavailableintwopublications.Followingapprovals by the B18 Committee and sponsor organizations, the proposal was submitted to theAmerican Standards Association and declared an American Standard on February 2, 1955.A revision
28、 of this document comprised of numerous editorial corrections and inclusions of anappendix for grade markings was duly approved and designated an American Standard onApril 18, 1960.At a meeting in February 1960, Subcommittee 2 approved a recommendation to reduce the headheights for heavy, heavy semi
29、finished, and heavy finished hexagon bolts which was subsequentlyapproved by letter ballot of the B18 Committee on August 16, 1960. A proposed standard forheavy hexagon structural bolts submitted and accepted by Subcommittee 2 at its October 17, 1960meeting was approved by letter ballot of the B18 C
30、ommittee on May 9, 1961. To meet the urgentneeds of the steel construction industry, it was considered necessary to publish the Standard forthe structural bolts immediately. Consequently, Appendix IV to ASA B18.2-1960 containing cover-age for the revised heavy hexagon bolts and the new heavy hexagon
31、 structural bolts was releasedin 1962.In October of 1961, Subcommittee 2 appointed a subgroup to review all product standards forsquare and hexagon bolts, screws, and nuts, and to recommend simplifications which would becompatible with technical, production, and distribution advances that had occurr
32、ed over theprior several years. The subgroup presented its recommendations at a meeting of Subcommittee 2in October 1962. It was agreed that the internally and externally threaded products should bepublished in separate documents as suggested, and draft proposals for each were completed.Theproposedr
33、evisionforsquareandhexboltsand screwsincorporatedthefollowingsubgrouprecommendations: consolidation of hexagon head cap screws and finished hexagon bolts into asingle product, consolidation of heavy semifinished hexagon bolts and heavy finished hexagonboltsintoasingleproduct,eliminationofregularsemi
34、finishedhexagonbolts,newlengthtoleranc-ing values for all bolts and screws, documentation of a positive identification procedure fordetermining whether an externally threaded product should properly be designated a bolt or ascrew, and an abbreviated and purified set of product nomenclature reflectin
35、g application of theidentification procedure. Letter ballot of this proposal to the B18 Committee in March 1964resulted in several comments, which were resolved to the satisfaction of the Committee inJune 1964. Following acceptance by the sponsor organizations, the revision was submitted tothe Ameri
36、can Standards Association and was designated American Standard ASA B18.2.1 onSeptember 8, 1965.Subcommittee 2 in 1992 recognized the value of having all structural products in a singlestandard. In a revision initiated for the B18.2.1 Standard in that year, it was proposed to removethe heavy hex stru
37、ctural bolt from the B18.2.1 Standard, the heavy hex nut from the B18.2.2Standard and combine these with the dimensions of hardened steel washers from ASTM F 436and the compressible-washer-type direct tension indicator dimensions of ASTM F 959. This newStandard would then provide all standardized di
38、mensions for the fasteners intended for use instructural applications. The first draft of this Standard was submitted to Subcommittee 2 atits May 1993 meeting. It was subsequently approved as an American National Standard onDecember 4, 1996.In December of 2008 the B18.2 Subcommittee agreed to begin
39、the updating of ASME B18.2.6.The documents format was revised to meet the new guidelines for B18 Standards. The insidediametersofthehardenedwasher wererevisedtomatchtherevisedsizeindicated inASTMF436.An alternative design for the58in. size compressible-washer-type direct tension indicator wasintrodu
40、ced to simplify production tooling for some washer manufacturers. References to platingsand coatings in the various product sections were removed and the users of this Standard aredirected to the appropriate ASTM material standard to determine finish requirements in additionto other physical and mec
41、hanical properties. The quality assurance section was simplified byremoving the reference to ASME B18.18.1 and the list of designated inspection characteristics.Instead, users are directed to ASME B18.18.2 for the quality assurance requirements and samplingplans for all product characteristics.The r
42、evision of Section 2.1.6, Bearing Surface, was the final resolved issue. It was learned thata significant amount of ASTM A 325 and A 490 bolts have always been produced by the hotvheading method, which leaves a die seam across the bolt bearing surface. A sentence was addedto the section specifically
43、 stating that die seams are permissible. Even though no problems hadever been reported relative to the presence of the die seams, one concerned party raised anobjection to the addition of this statement. It was decided that this issue should be resolved byconducting a testing program to objectively
44、determine if die seams on structural bolt bearingsurfaces cause any detrimental performance in application. Several lots of ASTM A 325 and A490 bolts were tested in an ISO 17025 accredited laboratory. Bolts and nuts were assembled intension testing equipment with the tightening torque applied throug
45、h the rotation of the nut inone set of lots and then by rotating the bolts by their heads in another series of lots. An 88 pagereport was created, including details on the testing of all lots, bolt chemical and physical certifi-cates, photographs of each stage of testing, and the accreditation certi
46、ficate for the testing labora-tory. The report was submitted to Professor Emeritus Dr. John Fisher of Lehigh University forreview and comment. In his conclusion Dr. Fisher stated, “Hence I do not see any reason toconsider the installation of bolts with or without seams to differ in achieving the des
47、ired preloadthereby providingthe desired slipresistance. Thetorque variability isconsistent with paststudies.Seams are not a significant factor as demonstrated by this study.“ The Standard was publishedcontaining the statement permitting die seams on structural bolt bearing surfaces.This edition was
48、 approved by the American National Standards Institute on July 8, 2010.viASME 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.)STANDARDS COMMITTEE OFFICERSJ. Greenslade, C
49、hairD. S. George, Vice ChairR. D. Strong, Vice ChairC. J. Gomez, SecretarySTANDARDS COMMITTEE PERSONNELV. Cartina, ConsultantD. A. Clever, ConsultantA. P. Cockman, Ford Motor Co.C. A. Dugal, TSPJ. S. Foote, Contributing Member, Trade Association Management,Inc.C. J. Gomez, The American Society of Mechanical EngineersJ. Greenslade, Industrial Fasteners InstituteJ. J. Grey, Contributing Member, Fastener Consulting Services, Inc.B. Hasiuk, Contributing Member, Defense Supply CenterA. Herskovitz, ConsultantJ. Hubbard, Leland-Powell Fasteners, Inc.J. Jennings, Contributing Member, Nav
