1、Designation:D1422/D1422M13(Reapproved 2020)Standard Test Method forTwist in Single Spun Yarns by the Untwist-Retwist Method1This standard is issued under the fixed designation D1422/D1422M;the number immediately following the designation indicates theyear of original adoption or,in the case of revis
2、ion,the year of last revision.A number in parentheses indicates the year of lastreapproval.A superscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method2describes the determination of twist insingle spun yarns when only an approximation of the
3、 true twistis required.NOTE1For a more accurate method see Test Method D1423.1.2 This test method is applicable to spun single yarns incontinuous lengths,and also to spun yarns raveled fromfabrics,provided specimens at least 200 mm 8 in.long can beobtained.1.3 This test method has been found satisfa
4、ctory for use indetermining the approximate twist content in single ring spunyarns of all types and fiber contents,but not in open-end spunyarns.1.4 This specification shows the values in both inch-poundunits and SI units.The“inch-pound”units is the technicallycorrect name for the customary units us
5、ed in the United States.The“SI”units is the technically corrected name for the systemof metric units known as the International System of Units.Thevalues stated in either SI units or inch-pound units are to beregarded separately as standard.The values stated in eachsystem are not necessarily exact e
6、quivalents;therefore,toensure conformance with the standard,each system shall beused independently of the other,and values from the twosystems shall not be combined.1.5 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the u
7、ser of this standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.6 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in
8、the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:3D123 Terminology Relating to TextilesD1059 Test Method for Yarn Number Based
9、on Short-Length SpecimensD1423 Test Method for Twist in Yarns by Direct-CountingD2258 Practice for Sampling Yarn for TestingD3888 Terminology for Yarn Spinning SystemsD4849 Terminology Related to Yarns and Fibers3.Terminology3.1 Refer to Terminology D4849 for definitions of thefollowing terms used i
10、n this standard:direction of twist,singleyarn,spun yarn,twist,twist factor,twist multiplier,and yarn.3.2 Refer to Terminology D123 and Terminology D3888 fordefinitions of other terms used in this standard.4.Summary of Test Method4.1 A specimen is untwisted and then retwisted in theopposite direction
11、 until it contracts to its original length.It isassumed that the same amount of twist has been inserted as wasoriginally present.Twist,as turns per unit length,is calculatedas half the number of turns registered on the counter divided bythe specimen length.5.Significance and Use5.1 This test method
12、is used for acceptance testing in thetrade for economic reasons even though it is less accurate thanthe direct method,Test Method D1423.5.1.1 If there are differences or practical significance be-tween reported test results for two laboratories(or more),comparative tests should be performed to deter
13、mine if their isa statistical bias between them,using competent statisticalassistance.As a minimum,the test samples should be used thatare as homogeneous as possible,that are drawn from thematerial from which the disparate test results are obtained,andthat are assigned randomly in equal numbers to e
14、ach laboratoryfor testing.Other materials with established test values may be1This test method is under the jurisdiction ofASTM Committee D13 on Textilesand is the direct responsibility of Subcommittee D13.58 on Yarns and Fibers.Current edition approved Feb.1,2020.Published February 2020.Originallya
15、pproved in 1956.Last previous edition approved in 2013 as D1422 13.DOI:10.1520/D1422_D1422M-13R20.2This test method is commonly designated by the less precise term“Untwist-Twist Method.”3For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.
16、org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization