1、Metric PracticeGuide for theWelding IndustryAWS A1.1:2001An American National Standard550 N.W. LeJeune Road, Miami, Florida 33126AWS A1.1:2001An American National StandardApproved byAmerican National Standards InstituteOctober 1, 2001Metric Practice Guidefor the Welding IndustrySupersedes ANSI/AWS A
2、1.1:1998Prepared byAWS A1 Committee on Metric PracticeUnder the Direction ofAWS Technical Activities CommitteeApproved byAWS Board of DirectorsAbstractThis metric practice guide is based on the International System of Units (SI) as defined in the U.S. Federal Registernotice of July 28, 1998, “Metric
3、 System of Measurement: Interpretation of the International System of Units for theUnited States.” It includes the base units, derived units, and rules for their use. Also covered are conversion factors andrules for their use in converting inch-pound units to SI units.Recommendations are presented f
4、or style and usage in such areas as prefixes, punctuation, number grouping, etc.There are also suggestions to industry for managing the transition.Key WordsMetric practice, SI units, conversions, round-off rules, preferred numbersStatement on Use of AWS American National StandardsAll standards (code
5、s, specifications, recommended practices, methods, classifications, and guides) of the AmericanWelding Society are voluntary consensus standards that have been developed in accordance with the rules of the AmericanNational Standards Institute. When AWS standards are either incorporated in, or made p
6、art of, documents that areincluded in federal or state laws and regulations, or the regulations of other governmental bodies, their provisions carrythe full legal authority of the statute. In such cases, any changes in those AWS standards must be approved by thegovernmental body having statutory jur
7、isdiction before they can become a part of those laws and regulations. In allcases, these standards carry the full legal authority of the contract or other document that invokes the AWS standards.Where this contractual relationship exists, changes in or deviations from requirements of an AWS standar
8、d must be byagreement between the contracting parties.International Standard Book Number: 0-87171-658-5American Welding Society, 550 N.W. LeJeune Road, Miami, FL 33126 2002 by American Welding Society. All rights reservedPrinted in the United States of AmericaAWS American National Standards are deve
9、loped through a consensus standards development process that bringstogether volunteers representing varied viewpoints and interests to achieve consensus. While AWS administers the processand establishes rules to promote fairness in the development of consensus, it does not independently test, evalua
10、te, orverify the accuracy of any information or the soundness of any judgments contained in its standards.AWS disclaims liability for any injury to persons or to property, or other damages of any nature whatsoever, whether spe-cial, indirect, consequential or compensatory, directly or indirectly res
11、ulting from the publication, use of, or reliance on thisstandard. AWS also makes no guaranty or warranty as to the accuracy or completeness of any information published herein.In issuing and making this standard available, AWS is not undertaking to render professional or other services for or onbeha
12、lf of any person or entity. Nor is AWS undertaking to perform any duty owed by any person or entity to someoneelse. Anyone using these documents should rely on his or her own independent judgment or, as appropriate, seek the adviceof a competent professional in determining the exercise of reasonable
13、 care in any given circumstances.This standard may be superseded by the issuance of new editions. Users should ensure that they have the latest edition.Publication of this standard does not authorize infringement of any patent. AWS disclaims liability for the infringementof any patent resulting from
14、 the use or reliance on this standard.Finally, AWS does not monitor, police, or enforce compliance with this standard, nor does it have the power to do so.On occasion, text, tables, or figures are printed incorrectly (errata). Such errata, when discovered, are shown on theAmerican Welding Society we
15、b page (www.aws.org) under “Technical” in the Departments column.Official interpretations of any of the technical requirements of this standard may be obtained by sending a request, in writ-ing, to the Managing Director Technical Services, American Welding Society, 550 N.W. LeJeune Road, Miami, FL 3
16、3126(see Annex G). With regard to technical inquiries made concerning AWS standards, oral opinions on AWS standards maybe rendered. However, such opinions represent only the personal opinions of the particular individuals giving them. Theseindividuals do not speak on behalf of AWS, nor do these oral
17、 opinions constitute official or unofficial opinions or interpre-tations of AWS. In addition, oral opinions are informal and should not be used as a substitute for an official interpretation.This standard is subject to revision at any time by the AWS A1 Committee on Metric Practice. It must be revie
18、wed everyfive years and if not revised, it must be either reapproved or withdrawn. Comments (recommendations, additions, or dele-tions) and any pertinent data that may be of use in improving this standard are required and should be addressed to AWSHeadquarters. Such comments will receive careful con
19、sideration by the AWS A1 Committee on Metric Practice and the au-thor of the comments will be informed of the Committees response to the comments. Guests are invited to attend all meet-ings of the AWS A1 Committee on Metric Practice to express their comments verbally. Procedures for appeal of an adv
20、ersedecision concerning all such comments are provided in the Rules of Operation of the Technical Activities Committee. Acopy of these Rules can be obtained from the American Welding Society, 550 N.W. LeJeune Road, Miami, FL 33126.Photocopy RightsAuthorization to photocopy items for internal, person
21、al, or educational classroom use only, or the internal, personal, oreducational classroom use only of specific clients, is granted by the American Welding Society (AWS) provided that theappropriate fee is paid to the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923, Tel: 978-750-840
22、0;online: http:/.iiiPersonnelAWS A1 Committee on Metric PracticeR. D. Thomas, Jr., Chair R. D. Thomas and Co.J. L. Gayler, Secretary American Welding SocietyB. B. Barrow ConsultantJ. Caprarola Consultant*J. R. Frysinger College of CharlestonE. A. Mechtly University of IllinoisS. K. Saha New York Sta
23、te Department of TransportationG. D. Uttrachi ESAB Welding and Cutting*AdvisorvForeword(This Foreword is not a part of AWS A1.1:2001, Metric Practice Guide for the Welding Industry, but is included forinformation purposes only.)The present AWS Policy on Metrication states, in part, that “The AWS sup
24、ports a timely transition to the use of SIunits. The AWS recognizes that the inch-pound system of units will eventually be replaced by the SI units. To delay thetransition to SI units and to lengthen unnecessarily the transition period results in greater costs and confusion andincreases the loss of
25、compatibility with the international market.”At the present time, the U.S. stands alone as the only industrial country that still predominantly uses the inch-poundunits of measurement. Since the signing of the Metric Act of 1975 by President Ford and an initial flurry of transition,the voluntary fea
26、ture of the Act allowed the impetus to stagnate. We now find ourselves at odds not only with otherindustrial countries, but also, in many cases, with each other.Many major companiesincluding General Motors Corporation, Ford Motor Company, DaimlerChrysler Corporationand an estimated 70% of the Fortun
27、e 500have made the switch in some aspect of their businesses. But smaller firms,typically those with fewer international interactions, have been slower to change.More recently, the Omnibus Trade and Competitiveness Act, which was signed by President Reagan in August 1988,designated the SI version of
28、 the metric system of units as preferred for U.S. trade and commerce. Specifically, this Actrequires each Federal Agency to use the metric system in its procurements, grants, and other business-related activities.A Metric Practice Subcommittee was formed under the AWS Committee on Definitions, Symbo
29、ls, and Metric Prac-tice in 1973 to provide guidance to the welding industry in the use of and conversion to SI units. The continued interestin metric practice within the AWS resulted in the reorganization of the former Metric Practice Subcommittee into thepresent AWS A1 Committee on Metric Practice
30、. Because a comprehensive document relating specifically to weldingnomenclature was not available, the first task of the subcommittee was to prepare a metric practice guide. The 1st editionwas issued in 1975. Improvements suggested by readers and users resulted in revisions in 1980, 1989, and 1998.
31、This 5thedition reflects the current “state of the art” in metric practice for the U.S. welding industry and will assist the weldingindustry in converting to SI units and promote their voluntary use.Comments and suggestions for the improvement of this standard are welcome. They should be sent to the
32、 Secretary,AWS A1 Committee on Metric Practice, American Welding Society, 550 N.W. LeJeune Road, Miami, FL 33126.Official interpretations of any of the technical requirements of this standard may be obtained by sending a request, inwriting, to the Managing Director, Technical Services Division, Amer
33、ican Welding Society (see Annex G). A formalreply will be issued after it has been reviewed by the appropriate personnel following established procedures.viiTable of ContentsPage No.Personnel iiiForeword.vList of Tables. viii1. Scope 12. The International System of Units (SI) 12.1 Completeness .12.2
34、 Coherence.12.3 Uniqueness .12.4 Advantages of the SI 13. SI Units and Symbols .13.1 SI Base Units23.2 SI Derived Units.23.3 Prefixes.24. Other Units Used with SI .25. Units Pertaining to Welding .26. Style and Usage 26.1 Application and Usage of Prefixes.26.2 Mass, Force, and Weight56.3 Temperature
35、56.4 Time .66.5 Angles 66.6 Stress and Pressure.66.7 Capitalization .66.8 Plurals.66.9 Punctuation.76.10 Writing Numbers76.11 Miscellaneous Styling77. Conversions 87.1 Rules for Converting and Rounding.87.2 Inch to Millimeter Conversion .87.3 Other Conversions127.4 Round-Off Rules 138. Transition138
36、.1 Introduction138.2 Considerations139. Preferred Numbers149.1 Definition .149.2 Application of Preferred Numbers.159.3 Value of Using Preferred Numbers 15AnnexesNonmandatory InformationAnnex AInch to Millimeter Conversion.17Annex BPounds-Force per Square Inch to Kilopascal Conversion.19Annex CFahre
37、nheitCelsius Temperature Conversion21Annex DOther Documents 25Annex EOther Organizations 27Annex FUnits for Newtons Second Law 29Annex GGuidelines for Preparation of Technical Inquiries for AWS Technical Committees .31viiiList of TablesTable Page No.1 SI Base Units22 Examples of SI Derived Units33 S
38、I Prefixes 44 Other Units Which May be Used with SI Units.45 Units Pertaining to Welding.56 Filler Metal Sizes .67 Fillet Sizes68 General Conversions 99 Conversions for Common Welding Terms.1010 Millimeter Value Round-Off Using Inch Tolerance Span1111 Comparison of Round-Off Methods A and B1112 Basi
39、c Preferred NumbersDecimal Series.16AWS A1.1:200111. ScopeThis metric practice guide is based on the Inter-national System of Units (SI) as defined in the U.S. Fed-eral Register notice of July 28, 1998, “Metric System ofMeasurement: Interpretation of the International Systemof Units for the United S
40、tates.” (Other source documentsand style guides are referenced in Annex D.) This guidecontains specifications of the SI base units, derived units,prefixes, and rules for their use in AWS documents andby the welding industry. It also contains factors and rulesfor converting from inch-pound units (oft
41、en referred to asU.S. Customary Units) to SI Units and recommendationsto industry for managing the transition.2. The International System of Units (SI)A system of units is any collection of related units.SI is the only system that has the properties outlined in2.12.3.2.1 Completeness. Completeness r
42、equires that a unit ofmeasurement be defined for every quantity of interest inthe physical sciences and technologies.2.2 Coherence. Coherence requires that all derived unitsin the system be obtained from the base units by the rulesof multiplication and division with no numerical factorother than the
43、 number one (1) ever occurring in the ex-pressions for derived units in terms of the base units. Thesystem of units must also be coherent with its corre-sponding system of quantities and equations. A systemof units is coherent with respect to a system of quantitiesand equations if the system of unit
44、s is chosen in such away that the equations between numerical values haveexactly the same form (including numerical factors) asthe corresponding equations between quantities.2.3 Uniqueness. Uniqueness requires that there be one,and only one, unit defined for each quantity. For exam-ple, the SI Units
45、 for force (newton), energy (joule), andpower (watt) are the same, respectively, whether the pro-cess is mechanical, electrical, or thermal.2.4 Advantages of the SI. The International System ofUnits (SI) is the metric system of units in its latest form.SI is the only system of units which fully sati
46、sfies all theabove three requirements for completeness, coherence,and uniqueness. Within SI, a set of base-ten prefixes isdefined to form decimal multiples and submultiples of SIUnits. SI Units and their base-ten multiples and submul-tiples are in harmony with our decimal system of arith-metic, faci
47、litating easy numerical calculations. Awkwardmanipulations of common fractions such as 1/16, 1/32,and 1/64 are completely unnecessary. All industrial na-tions, including the United States by the Omnibus Tradeand Competitiveness Act of 1988 (Public Law 100-418),have chosen the SI as the preferred sys
48、tem of units for allapplications in science, engineering, technology, com-merce, and trade.3. SI Units and SymbolsSI consists of seven base units, derived units, and a set ofprefixes for the formation of multiples of the various units.Metric Practice Guidefor the Welding IndustryQuantityDerivedUnit
49、Unit EquationForce (mass times acceleration)F = m anewton 1 N = 1 kg m/s2Energy (force times distance)E = F ljoule 1 J = 1 N mPower (rate of energy transfer)P = E/twatt 1 W = 1 J/sPressure (force divided by area)p = F/Apascal 1 Pa = 1 N/m2AWS A1.1:200123.1 SI Base Units. Names of SI base quantities, names ofcorresponding SI base units, their symbols, and defini-tions are given in Table 1.3.2 SI Derived Units. SI derived units are formed as de-scribed in 2.2. Some of them have been given specialnames and symbols. Examples are listed in Table 2.3.3 Pref
