1、AN AMERICAN NATIONAL STANDARDMetric Formed Hex ScrewsASME B18.2.3.2M-2005Revision of ASME B18.2.3.2M-1979 (R1995)ASME B18.2.3.2M-2005Revision of ASME B18.2.3.2M-1979 (R1995)Screw, Cap, Formed Hex Head -Metric FormedHex ScrewsThree Park Avenue New York, NY 10016AN AMERICAN NATIONAL STANDARDDate of Is
2、suance: September 14, 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 interpretations of technical aspects of this Stan-dard. Interpretations are published on
3、 the ASME Web site under the Committee Pages athttp:/www.asme.org/codes/ 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 National Stan-dards. The S
4、tandards 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 pu
5、blic 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 item
6、smentioned in this document, and does not undertake to insure anyone utilizing a standard against liability for infringe-ment of any applicable letters patent, nor assumes any such liability. Users of a code or standard are expressly advisedthat determination of the validity of any such patent right
7、s, 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 th
8、ose 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 p
9、ermission of the publisher.The American Society of Mechanical EngineersThree Park Avenue, New York, NY 10016-5990Copyright 2005 byTHE AMERICAN SOCIETY OF MECHANICAL ENGINEERSAll rights reservedPrinted in U.S.A.CONTENTSForeword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10、 . . . . . . . . . . . . . . . . . . . . . . . . . . . ivCommittee Roster . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vCorrespondence With the B18 Committee . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11、 . vi1 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Comparison With ISO Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Terminology . . . . . . . . . . . . . . . . . .
12、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Referenced Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13、 . . . . . . . . . . . . . 16 General Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2Figures1 Formed Hex Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Fillet Details
14、 For Short Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 Fillet Details For Long Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3A1 Typical Straightness Gage . . . . . . . . . . . . . . . . . . . . . . . . .
15、. . . . . . . . . . . . . . . . . . . . 9B1 Typical Gage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10Tables1Dimensions of Formed Hex Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Tolerance Zon
16、e . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 Dimensions of Underhead Fillets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44Dimensions of Reduced Body Diameter With Shoulder . . . . . . . . . . . .
17、 . . . . . . . . . . 45Maximum Grip Gaging Lengths and Minimum Body Lengths . . . . . . . . . . . . . . . . . 56 Length Tolerances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 Dimensions of Points . . . . . . . . . . . . . . . . . . . . . .
18、 . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 Thread Lengths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Nonmandatory AppendicesA Screw Straightness Gage and Gaging Procedure . . . . . . . . . . . . . . . . . . . . . . . . .
19、. . . 9B Body Position Gages and Gaging Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10C Comparison With ISO Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11iiiFOREWORDAmerican National Standards Committee B18 for the standardizat
20、ion 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, then the United States of America Standards Institute and, as of October 6, 196
21、9, the Amer-ican National Standards Institute, Inc.), with the Society of Automotive Engineers and the Amer-ican Society of Mechanical Engineers as joint sponsors. Subcommittee 2 was subsequentlyestablished and charged with the responsibility for technical content of standards covering wrenchhead bo
22、lts and nuts.At its meeting on December 4, 1974, Committee B18 authorized preparation of a series of stan-dards for metric fasteners. Subcommittee 2 was assigned responsibility for developing standardsfor metric hex bolts, screws, and nuts.At a meeting on September 22, 1976, Subcommittee 2 organized
23、 the contents of a standard cov-ering eight different hex head screw and bolt products. Actual drafting was postponed untilISO/TC2 could reach final decisions relating to basic dimensions and characteristics of hex bolts,screws, and nuts. At ISO/TC2 meetings held in April 1977, final actions were ta
24、ken. CommitteeB18 affirmed the TC2 decisions at a meeting on June 29, 1977 and drafting of this Standard wasstarted.In February 1978, Committee B18 established a cooperative program with the Department ofDefense to draft American National Standards for metric fasteners in such a way that they couldb
25、e used directly by the Government for procurement purposes. The Department of Defense re-quested that each of the eight products be covered in separate standards, and Subcommittee 2accepted this approach at its meeting on June 27, 1978.The previous edition of this Standard was approved by letter bal
26、lot of Committee B18 on De-cember 15, 1978, and was subsequently approved by the secretariat and submitted to the Amer-ican National Standards Institute for designation as an American National Standard. This wasgranted on March 29, 1979. B18.2.3.2M was last reaffirmed without change in 1995.This Sta
27、ndard was developed by the American Society of Mechanical Engineers B18 StandardsCommittee on Fasteners. This Standard was approved by the American National Standards In-stitute on April 29, 2005.ivASME B18 COMMITTEEStandardization of Bolts, Nuts, Rivets, Screws,Washers, and Similar Fasteners(The fo
28、llowing is the roster of the Committee at the time of approval of this Standard.)OFFICERSD. A. Clever, ChairR. D. Strong, Vice ChairS. W. Vass, Vice ChairR. L. Crane, SecretaryCOMMITTEE PERSONNELvW. H. Kopke, ITW Shakeproof Assembly ComponentsM. Levinson, Alternate, ITW ShakeproofJ. G. Langenstein,
29、Emeritus Member, ConsultantL. L. Lord, Corresponding Member, ConsultantW. J. Lutkus, Heli Coil EmhartA. D. McCrindle, Canadian Fasteners InstituteK. E. McCullough, ConsultantM. D. Prasad, General Motors Corp.J. A. Roley, Corresponding Member, Caterpillar, Inc.W. L. Sakowski, Account Managers LLCS. S
30、avoji, ITW MedalistW. Schevey, BGM Fastener Company, Inc.W. R. Stevens, RamcoR. D. Strong, General Motors Corp.S. W. Vass, Nova Machine ProductsC. B. Wackrow, MNP Corp.R. G. Weber, Fairfield UniversityW. K. Wilcox, ConsultantC. J. Wilson, Industrial Fasteners InstituteR. B. Wright, Wright Tool Co.J.
31、 G. Zeratsky, National Rivet however, theyshould not contain proprietary names or information.Requests that are not in this format will be rewritten in this format by the Committee prior tobeing answered, which may inadvertently change the intent of the original request.ASME procedures provide for r
32、econsideration of any interpretation when or if additional in-formation that might affect an interpretation is available. Further, persons aggrieved by an in-terpretation may appeal to the cognizant ASME Committee or Subcommittee. ASME does not“approve,” “certify,” “rate,” or “endorse” any item, con
33、struction, proprietary device, or activity.Attending Committee Meetings. The B18 Standards Committee regularly holds meetings, whichare open to the public. Persons wishing to attend any meeting should contact the Secretary of theB18 Standards Committee.viMETRIC FORMED HEX SCREWS1 SCOPE(a) This Stand
34、ard covers the complete dimensionaland general data for metric formed hex screws recog-nized as American National Standard. Formed hexscrews are cold formed products with fully upset(non-trimmed) heads. Formed hex screws are stan-dard only in sizes M5 thru M24, with lengths up to150 mm, or 10 times
35、nominal screw size, whichever isshorter.(b) The inclusion of dimensional data in this Stan-dard is not intended to imply that all of the sizes inconjunction with the various options described hereinare stock items. Consumers should consult with sup-pliers concerning lists of stock production formed
36、hexscrews.2 COMPARISON WITH ISO STANDARDS(a) Because of numerous differences between thisStandard and ISO 4015, a detailed summary is includedin Appendix C.(b) At its meeting in Varna, May 1977, ISO/TC2studied several technical reports analyzing design con-siderations influencing determination of th
37、e best seriesof width across flats for hexagon bolts, screws, andnuts. A primary technical objective was to achieve alogical ratio between underhead (nut) bearing surfacearea (which determines the magnitude of the com-pressive stress on the bolted members) and the tensilestress area of the screw thr
38、ead (which governs theclamping force that can be developed by tightening thefastener). Table 1 lists the sizes selected by ISO/TC2 tobe ISO standard.M10 screws with 15 mm width across flats are cur-rently being produced and used in the U.S. and manyother countries. This size, however, is not an ISO
39、stan-dard. Unless M10 screws with 15 mm width across flatsare specifically ordered, M10 screws with 16 mm widthacross flats shall be furnished.(c) Letter symbols designating dimensional charac-teristics are in accord with those used in ISO standards,except that capital letters have been used instead
40、 of thelower case letters used in ISO standards.3 TERMINOLOGYFor definitions of terms relating to fasteners or com-ponent features thereof used in this Standard, refer toAmerican National Standard ASME B18.12.ASME B18.2.3.2M-200514 REFERENCED STANDARDSThe following is a list of publications referenc
41、ed inthis Standard.ASME B1.3M, Screw Thread Gaging Systems for Di-mensional Acceptability Inch and Metric ScrewThreads (UN, UNR, UNJ, M, and MJ)ASME B1.13M, Metric Screw Threads M ProfileASME B18.2.8, Clearance Holes for Bolts, Screws andStudsASME B18.12, Glossary of Terms for Mechanical Fas-tenersA
42、SME B18.18.1, Inspection and Quality Assurance forGeneral Purpose FastenersASME B18.18.2, Inspection and Quality Assurance forHigh Volume Machine Assembly FastenersASME B18.24.1, Part Identifying Number (PIN) CodeSystem Standard for B18 Fasteners ExternallyThreaded ProductsASME Y 14.5M, Dimensioning
43、 and TolerancingPublisher: The American Society of Mechanical Engi-neers (ASME), Three Park Avenue, New York, NY10016-5990; Order Department: 22 Law Drive, Box2300, Fairfield, NJ 07007-2300ASTM F 468M, Nonferrous Bolts, Hex Cap Screws andStuds for General Use (Metric)ASTM F 568M, Carbon and Alloy St
44、eel ExternallyThreaded FastenersASTM F 738M, Stainless Steel Metric Bolts, Screws andStudsASTM F 788/F 788M, Surface Discontinuities of Bolts,Screws, and Studs Inch and Metric SeriesPublisher: The American Society for Testing and Mate-rials (ASTM), 100 Barr Harbor Drive, West Con-shohocken, PA 19428
45、-2959.ISO 4015, Hexagon Head Bolts Product Grade B Reduced Shank (shank diameter approximately equalto pitch diameter)Publisher: International Organization for Standardiza-tion (ISO), Rue de Varemb, Case Postale 56, CH-1211,Geneve 20, Switzerland.5 DIMENSIONS(a) All dimensions in this Standard are g
46、iven in mil-limeters (mm), and apply before coating, unless statedotherwise.(b) Symbols specifying geometric characteristics arein accordance with ASME Y14.5M.ASME B18.2.3.2M-2005 METRIC FORMED HEX SCREWS2Table 1 Dimensions of Formed Hex ScrewsRunout ofNominalWidth Width Wrenching Washer Face Washer
47、 Face BearingScrew DiameterBody Across Across Head Height, Thickness, Diameter, Surfaceand ThreadDiameter, DsFlats, S Corners, E Height, KKwCDwFIMPitch, D Max. Min. Max. Min. Max. Min. Max. Min. Min. Max. Min. Min. Max.M5 H11003 0.85.00 4.82 8.00 7.64 9.24 8.56 3.65 3.35 2.40.50.26.90.22M6 H11003 16
48、.00 5.82 10.00 9.64 11.55 10.80 4.15 3.85 2.00.50.28. .25M8 H11003 1.25 8.00 7.78 13.00 12.57 15.01 14.08 5.50 5.10 3.70.60.311.60.28M10 H11003 1.510.00 9.78 15.00 14.57 17.32 16.32 6.63 6.17 4.50.60.313. .31M10 H11003 1.510.00 9.78 16.00 15.57 18.48 17.43 6.63 6.17 4.50.60.314.60.32M12 H11003 1.75
49、12.00 11.73 18.00 17.57 20.78 19.68 7.76 7.24 5.20.60.316. .35M14 H11003 214.00 13.73 21.00 20.16 24.25 22.58 9.09 8.51 6.20.60.319.60.39M16 H11003 6.00 15.73 24.00 23.16 27.71 25.94 10.32 9.68 7.00.80.422.50.43M20 H11003 2.520.00 19.67 30.00 29.16 34.64 32.66 12.88 12.12 8.80.80.427.70.53M24 H11003 324.00 23.67 36.00 35.00 41.57 39.20 15.44 14.46 10.50.80.433.20.63See para. 6.2 . 6.1.3, 6.1.46.1.26.1.3 . 6.1.66.1.6GENERAL NOTE: See para. 6.2 of General Data.Para. 6.1.6Fillet(see para. 6.1.7)(X)(B)See para. 6.6.4See para. 6.6.330H1103415H11034Indentation andconfigurationopti
