1、Designation:D1423/D1423M16Standard Test Method forTwist in Yarns by Direct-Counting1This standard is issued under the fixed designation D1423/D1423M;the number immediately following the designation indicates theyear of original adoption or,in the case of revision,the year of last revision.A number i
2、n parentheses indicates the year of lastreapproval.A superscript epsilon()indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope1.1 This test method covers the determination of the amountand dir
3、ection of twist at the completion of any stage of twistingin single(spun or filament),plied,cabled,or novelty(exclusiveof long-term repeat patterns)yarns.The procedures are de-signed primarily for yarns in packages,but,with specialprecautions,they are applicable to yarns taken from fabrics.The proce
4、dure for spun yarn in 9.2 is also applicable torovings.1.2 For plied yarns,this test method covers the determina-tion of the twist of the plied yarns and the twist of the singleyarn before plying.For cabled yarns,the test method covers thedetermination of the cable or hawser twist;the twist of thepl
5、ied yarn after plying,but prior to the last twisting operation;and the twist of the single yarn before plying.Procedures arealso included for the determination of the twists of the singleand plied yarn components as they lie in the final structure.Also,directions are included for the determination o
6、f twist inplied yarn made with direct cabling technology.1.3 This test method is not intended for yarns that extendmore than 5.0%when tension is increased from 2.5 to 7.5mN/tex 0.25 to 0.75 gf/tex.Following the procedures of thistest method for such yarns would be independent of the biasand precisio
7、n determined for this test method.The report fromsuch testing should include the tension used for this testing.1.4 UnitsThe values stated in either SI units or inch-pound units are to be regarded separately as standard.Thevalues stated in each system may not be exact equivalents;therefore,each syste
8、m shall be used independently of the other.Combining values from the two systems may result in non-conformance with the standard.NOTE1For a more rapid but less accurate method of determiningtwist in single spun yarns,refer to Test Method D1422.NOTE2This test method has been evaluated for use in dete
9、rminingtwist in open end yarns and is not recommended.1.5This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of r
10、egulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D123 Terminology Relating to TextilesD1059 Test Method for Yarn Number Based on Short-Length Specimens(Withdrawn 2010)3D1422 Test Method for Twist in Single Spun Yarns by theUntwist-Retwist MethodD1776 Practice for Conditio
11、ning and Testing TextilesD1907 Test Method for Linear Density of Yarn(Yarn Num-ber)by the Skein MethodD3888 Terminology for Yarn Spinning SystemsD4849 Terminology Related to Yarns and Fibers3.Terminology3.1 Refer to Terminology D4849 for definitions of thefollowing terms used in this standard:direct
12、ion 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 specified length of specimen is mounted in a twistdevice.One end is rotated until all t
13、he elements are free oftwist.The number of turns is counted and the turns per unitlength are calculated.4.2 The amount of twist in the component elements of aplied or cabled yarn is determined by either of two options.4.2.1 In the procedure for determining original twist,oneend of the yarn is fixed
14、while the other end is rotated until the1This 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 July 1,2016.Published October 2016.Originallyapproved in 1956.Last previous edition
15、 approved in 2008 as D142302(2008).DOI:10.1520/D1423_D1423M-16.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3Th
16、e last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 structural components are parallel.Any one or all of thesecomponents may then be used as test specimens.4.2.2 In the procedure for determining final twist incomponents,both ends of one component of the yarn are heldfixed while all the other components are removed and dis-carded.The twist is then determined i