1、STD.ASME B18.2.b-EN6L1996w075967005B3071B49mSMfB18.2.61996FASTENERS FOR USEIN STRUCTURALAPPLICALIONSAN AMERICAN NATIONAL STANDARDThe American Society ofMechanical EngineersCopyright by the American Society Of Mechanical EngineersSTD.ASME B8.2.6-EN6L199b07596700583075494ballot in September 1951.Follo
2、wing approval by the B18 Committee and the sponsors,the pro-posal was presented to the American Standards Association for approval and designation as anAmerican Standard.This was granted on March 24,1952.Recognizing the standard was in need of additional refinements,Subcommittee 2 began im-mediately
3、 to revise it,removing inconsistencies with respect to fillets,improving the length tol-erances on heavy hexagon bolts,and incorporating numerous other corrections and clarifica-tions.The most noteworthy editorial change was a decision to combine the coverage for hexagoncap screws and square head se
4、t screws from the B18.2 standard with the coverage for slottedhead cap screws and slotted headless set screws from the B18.6 standard and publish them ina separate document.The requirements for the unified hexagon cap screws and finished hexa-gon bolts being identical in the overlapping sizes,this d
5、ata would now be available in two pub-lications.Following approvals by the B18 Committee and sponsor organizations.the proposalwas submitted to the American Standards Association and declared an American Standard onFebruary 2.1955.A revision of this document comprised of numerous editorial correctio
6、ns and inclusion of anappendix for grade markings was duly approved and designated an American Standard on April18.1960.At a meeting in February 1960,Subcommittee 2 approved a recommendation to reduce the headheights for heavy,heavy semi-finished,and heavy finished hexagon bolts which was subscqucnt
7、lyapproved by letter ballot of the B18 Committee on August 16,1960.A proposed standard for heavyhexagon structural boits submnitted and accepied by Subcommnittee 2 at its October 17.1960 meet-ing was approved by letter ballot of the B18 Committee on May 9,1961.To ineet the urgent needsof the steel c
8、onstruction industry,it was considered necessary to publish the standard for the suuc-tural bolts immediately.Conscquently,Appendix IV to ASA B18.2-1960 containing coverage forthe revised heavy hexagon bolts and the new heavy hexagon structural bolts was released in 1962.In October of 1961,Subcommit
9、tee 2 appointed a subgroup to revicw all product standardsfor square and hexagon bolts,serews,and nuts,and to recommend simplifications which wouldbe compatible with technical,production,and distribution advances that had occurred over theprior several years.The subgroup presented its recommendation
10、s at a meeting of Subcommittee2 in October of 1962.It was agreed that the internally and exterally threaded products shouldbe published in separate documents as suggested,and draft proposals for each were completed.The proposed revision for square and hex bolts and serews incorporated the following
11、subgrouprecommendations:consolidation of hexagon head cap screws and finished hexagon bolts into asingle product;consolidation of heavy semifinished hexagon bolts and heavy finished hexagonbolts into a single product;elimination of regular semifinished hexagon bolts;a new length toler-ancing pattern
12、 for all bolts and screws:documentation of a positive identification procedure fordetermining whether an extemally threaded product should properly be designated a bolt or a screw:and an abbreviated and purified set of product nomenclature reflecting application of the identifi-cation procedure.Lett
13、er ballot of this proposal to the B18 Committee in March 1964 resulted inseveral comments which were resolved to the satisfaction of the Committee in June of 1964Following acceptance by the sponsor organizations.the revision was submitted to the AmericanStandards Association and was designated Ameri
14、can Standard ASA B18.2.I on Septemher 8.1965Subcommittee 2 in 1992 recognized the values 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 Structural Bolt from the B18.2.1 standard,the Heavy Hex
15、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.Thisnew standard would then provide all standardized dimensions for the fasteners intended for usein structural applications.The first draft of this Standard was submitted to Subcommittee 2 atits May 1993 mecting.ASME B18.2.6-1996 was approved by the American National Standards Institute(ANSI)onDecember 4,1996.
