1、AN AMERICAN NATIONAL STANDARDUnified Inch Screw Threads(UN and UNR Thread Form)ASME B1.1-2003Revision of ASME B1.1-1989 (R2001)Intentionally left blank AN AMERICAN NATIONAL STANDARDUNIFIED INCHSCREW THREADS(UN and UNR Thread Form)ASME B1.1-2003Revision of ASME B1.1-1989 (R2001)Date of Issuance: Sept
2、ember 30, 2004The 2004 edition of this Standard is being issued with an automatic addenda subscription service.The use of addenda allows revisions made in response to public review comments or committeeactions to be published as necessary. This Standard will be revised when the Society approves thei
3、ssuance of a new edition.There will be no written interpretations of the requirements of this Standard issued to this edition.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 A
4、merican 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 for public review and comment that provides an o
5、pportunity for additional public 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
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8、ponsibility 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,with
9、out the prior written permission of the publisher.The American Society of Mechanical EngineersThree Park Avenue, New York, NY 10016-5990Copyright 2004 byTHE AMERICAN SOCIETY OF MECHANICAL ENGINEERSAll rights reservedPrinted in U.S.A.CONTENTSForeword viCommittee Roster viii1 General . 11.1 Scope 11.2
10、 Unified Screw Thread Standards 11.3 UN and UNR Screw Threads . 11.4 Interchangeability 11.5 Designations . 11.6 Reference Documents . 11.7 Acceptability . 21.8 Reference Temperature 21.9 Units of Measure . 21.10 Federal Government Use 22 Screw Thread Profile . 22.1 Scope 22.2 Basic Profile 22.3 Des
11、ign Profiles . 22.4 Formulas and Symbols . 23 Screw Thread Series . 23.1 Thread Series Definition 23.2 Order of Selection 23.3 Coarse-Thread Series Applications 33.4 Fine-Thread Series Applications. 33.5 Extra-Fine-Thread Series Applications . 33.6 Constant-Pitch Thread Series Applications. 33.7 Fin
12、e Threads for Thin-Wall Tubing 74 Screw Thread Classes 364.1 Thread Classes . 364.2 Combinations of Classes 365 Screw Thread Allowance and Tolerance 365.1 Allowance 365.2 Pitch Diameter Tolerance, All Classes . 365.3 Special Lengths of Engagement, LE . 375.4 Minor Diameter Tolerance and Allowance fo
13、r External Threads 545.5 Major Diameter Tolerance for Internal Threads 545.6 Minor Diameter Tolerance and Length of Engagement for InternalThreads 555.7 Disposition of Allowance and Tolerance . 555.8 Formulas for Allowance and Tolerance 555.9 Lead and Flank Angle Tolerances . 585.10 Coated or Plated
14、 Threads. 585.11 Circular Runout 586 Screw Thread Designation 586.1 Basic Method of Designating 58iii6.2 Method of Designating Coated Threads . 616.3 Method of Designating Left-Hand Threads 626.4 Method of Designating UNS Threads . 626.5 Designations for Other Threads . 626.6 Method of Designating T
15、hreads Having Special Length ofEngagement 636.7 Method of Designating Threads Having Modified Crests. 637 Dimensional Accommodation of Coating or Plating for 60-deg Threads 647.1 Introduction 647.2 Material Lifts for Coated Threads . 647.3 Dimensional Effects of Coating . 647.4 External Thread With
16、Allowance Available for Coating 647.5 External Thread With No Allowance for Coating 647.6 Internal Threads 667.7 Electrodeposited Coatings 677.8 Other Considerations . 678 Standard Series Threads (UN/UNR) and Limits of Size for Standard Seriesand UNS/UNRS Series Threads . 678.1 Standard Series. 678.
17、2 Limits of Size 678.3 Formulas for Limits of Size . 678.4 Example of Calculations From Formulas 689 Lead and Angle Tolerances . 689.1 Lead and Flank Angle Acceptance 6810 Formulas and Symbols for Thread Form . 6910.1 Thread Form Formulas and Symbols 6911 Tables of Basic Dimensions . 7011.1 Table Co
18、ntent 7011.2 Thread Series. 70Figures1 Basic Profile for UN and UNR Screw Threads 32 Disposition of Diametral Tolerances, Allowance, and Crest Clearance forUnified Inch Screw Thread Classes 1A, 2A, 1B, and 2B . 43 Disposition of Diametral Tolerances and Crest Clearances for Unified InchScrew Thread
19、Classes 3A and 3B. 54 Ratio of Pitch Diameter Change to Thickness of Coating on 60-degThreads . 655 Effect of Electrodeposited Coatings on 60-deg External Threads . 666 Application of General Thread Symbols 70Tables1 Standard Series Threads (UN/UNR) . 62 Limits of Size for Standard Series Threads (U
20、N/UNR) 83 Allowable Variations in Lead and Equivalent Change in FunctionalDiameter 384 Increments in Pitch Diameter Tolerance Class 2A 565 Thread Form Data . 596 Basic Dimensions for Coarse-Thread Series (UNC/UNRC) 727 Basic Dimensions for Fine-Thread Series (UNF/UNRF) . 738 Basic Dimensions for Ext
21、ra-Fine-Thread Series (UNEF/UNREF) . 749 Basic Dimensions for 4-Thread Series (4-UN/4-UNR) . 75iv10 Basic Dimensions for 6-Thread Series (6-UN/6-UNR) . 7611 Basic Dimensions for 8-Thread Series (8-UN/8-UNR) . 7712 Basic Dimensions for 12-Thread Series (12-UN/12-UNR) 7913 Basic Dimensions for 16-Thre
22、ad Series (16-UN/16-UNR) 8114 Basic Dimensions for 20-Thread Series (20-UN/20-UNR) 8315 Basic Dimensions for 28-Thread Series (28-UN/28-UNR) 8416 Basic Dimensions for 32-Thread Series (32-UN/32-UNR) 8517A Outline Guide for Determining Limits of Size of External Threads 8617B Outline Guide for Determ
23、ining Limits of Size of Internal Threads . 8618A Examples of External Screw Threads . 8718B Examples of Internal Screw Threads 9019 Allowable Variation in 30 deg Basic Half Angle of External and InternalScrew Threads. 9220 General Symbols. 93Nonmandatory AppendicesA Terminology and Identification of
24、 Unified Inch Screw Threads 95B Thread Strength Design Formulas 97C Unified Inch Screw Threads Metric Translation 98D Special Threads 134E Changes to ASME B1.1-1989 Tables 3A and 3B 177vFOREWORDThis Standard is the outgrowth of and supersedes previous editions that were published asB1-1924, B1.1-193
25、5, B1.1-1949, B1.1-1960, B1.1-1974, B1.1-1982, and B1.1-1989. Throughout suchdevelopment, special attention has been given to the practical aspects of thread standardization,and many details of the current Standard result from studies and tests based on user problems.For example, there was disclosed
26、 the need for free assembly in high-production industries andthe desirability of making some provision for threads that require a coating. The tolerance classes2A/2B were developed to meet these two major requirements as well as to provide a generalstandard for externally and internally threaded fas
27、teners. Thread symbols and nomenclaturewere changed to be expressed according to ASME B1.7. Thread acceptability now refers toASME B1.3.This issue includes the following changes to ASME B1.1-1989:(a) The revision of some of the values in Table 2. These revisions are the result of the applicationof t
28、he consistent eight place decimal and rounding rules established in ASME B1.30-1992 thatwere mandated for use in all new and future revisions of ASME B1 documents. ASME B1.30 wasdeveloped under the direction of the B1 Committee as the basis for rounding of decimal valuesassociated with the computati
29、on of screw thread dimensions. Using the thread calculation formu-las in paras. 5 and 8 of this document and following the rounding rules of B1.30 all parties usinga calculator or standard computer spreadsheet program will derive precisely the same values.Table E-1 of Nonmandatory Appendix E identif
30、ies the thread sizes in Table 2 that have beenrevised and lists the dimensions from the ASME B1.1-1989 standard. The majority of the dimen-sional changes are within 0.0001 in.Paragraph 8.2.1 states that both the values in Tables 2 and E-1 should be considered acceptableuntil a future revision of thi
31、s standard makes the values in Table 2 the only acceptable values.(b) Former Table 3B has been moved to Nonmandatory Appendix D. This table providescalculated values for various UNS (Unified Specials). ASME B1 strongly urges the adoption ofthe standard thread sizes in Table 2 whenever possible inste
32、ad of those listed in Table D-1.(c) Former Tables 20 through 30 have been eliminated because the allowances and tolerancescontained in them was determined to be redundant with data provided in Table 2.(d) Former Tables 31 through 40 have been moved to Nonmandatory Appendix D and wererenamed Tables D
33、-2 through D-11. These tables were used in the past for the quick calculationof special threads. In some cases the derived values resulted in values that differ from thosederived by use of the formulas in paras. 5 and 8 of ASME B1.1. All future special threads shouldbe based on calculations in paras
34、. 5 and 8 in this document using the rounding rules in ASMEB1.30 to ensure uniformity and consistency.(e) All references to percent of thread engagement have been eliminated from this document.Past changes in the thread form designation of the “basic” thread height from 0.750H to 0.625Hconfused the
35、calculation of percent of thread engagement. This calculation has been used in thepast for threaded products users to determine drill size selection. It is now recommended thatusers select a drill size that will result in a hole size that lies between the maximum and minimumsize of the internal thre
36、ads minor diameter shown in the tables included in this Standard.(f) The definition of “functional diameter” has been included in this document and the termhas been added in Table 2 in the same column as “pitch diameter” since both characteristics havethe same limits of size.(g) The effects of coati
37、ng on threads have been explained in more depth in para. 7.The Unified Screw Threads Standard is an integrated system of threads for fastening purposesin mechanisms and structures. Its outstanding characteristic is general interchangeability ofthreads, achieved through the standardization of thread
38、form, diameter-pitch combinations, andlimits of size.The Standard has as its original basis the work done more than a century ago by WilliamSellers in the United States and Sir Joseph Whitworth in Great Britain. Throughout the interveningviyears there have been many further developments and revision
39、s, culminating in the system ofUnified Threads approved and adopted for use by all inch-using countries.The achievements represented by ASME B1.1 in development, standardization, and unificationare the result of cooperation and coordination of many organizations, including The AmericanSociety of Mec
40、hanical Engineers, Society of Automotive Engineers, National Institute of Scienceand Technology (formerly National Bureau of Standards), Committee B1, the former NationalScrew Thread Commission, the former Interdepartmental Screw Thread Committee, British Stan-dards Institution, Canadian Standards A
41、ssociation, and American National Standards Institute.Unification of screw thread standards received its impetus from the need for interchangeabilityamong the billions of fasteners used in the complex equipment of modern technology and madein different countries. Equally important, however, are inte
42、rnational trade in mechanisms of allkinds and the servicing of transportation equipment which moves from country to country. Thesehave made unification not only highly advantageous, but practically essential. In sizes14in. andlarger, complete unification of certain thread series and six tolerance cl
43、asses was signaled by thesigning of an accord on November 18, 1948. Since that time, further unification has been extendedinto smaller sizes. Working through Technical Committee No. 1 of the International Organizationfor Standardization (ISO), the unified standard was adopted as an ISO inch screw th
44、read standard,ISO 5864, parallel to the ISO metric screw thread system. Both systems have a common basicprofile. The standard was subject to Quadripartite Standardization Agreement (QSTAG) 247, inthe ABCA Army Standardization Program of America, Britain, Canada, and Australia.Suggestions for improve
45、ment of this Standard will be welcomed. They should be sent to theAmerican Society of Mechanical Engineers at ASME International, Three Park Avenue, New York,NY 10016-5990, U.S.A.ASME B1.1-2003 was approved by the American National Standards Institute (ANSI) on March27, 2003.viiASME STANDARDS COMMIT
46、TEE B1Standardization and Unification of Screw Threads(The following is the roster of the Committee at the time of approval of this Standard.)OFFICERSA. L. Barrows, ChairD. S. George, Vice ChairR. L. Crane, SecretaryCOMMITTEE PERSONNELG. L. Allen, L. S. Starret Co.A. L. Barrows, Kennametal IPGM. H.
47、Bernier, Standard Nut and BoltF. G. Calderone, Quality Systems ImplementersR. L. Crane, The American Society of Mechanical EngineersL. N. Dixon, Jr., General ElectricR. Dodge, Pennoyer-Dodge Co.G. A. Flannery, Mercury Gage Co.D. Skierski, Alternate, Mercury Gage Co.H. N. Frost, Defense Supply Center
48、 PhildelphiaJ. O. Gehret, Vermont Thread GageD. S. George, Ford Motor Co.J. R. Gervasi, Kerr Lakeside Inc.J. Greenslade, Greenslade however,this Standard covers only UN and UNR thread forms.For easy reference, a metric translation of this Stan-dard has been incorporated as Nonmandatory Appen-dix C.
49、Nonmandatory Appendices A through E containuseful information that is supplementary to the sectionsof this Standard.1.2 Unified Screw Thread StandardsThe standards for unified screw threads published inthis Standard are in agreement with formal standardsof the International Organization for Standardizationfor diameter-pitch combinations, designations, and tol-erances for 60 deg triangular form inch screw threads.Unified screw threads had their origin in an accordsigned in Washington, D.C., on November 18, 1948, byrepresentatives of standardizing bodies of Canada, theUnited King
