1、Designation:E145016Standard Test Method forTension Testing of Structural Alloys in Liquid Helium1This standard is issued under the fixed designation E1450;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A nu
2、mber in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method describes procedures for the tensiontesting of structural alloys in liquid helium.The format issimilar to that of other ASTM
3、 tension test standards,but thecontents include modifications for cryogenic testing whichrequires special apparatus,smaller specimens,and concern forserrated yielding,adiabatic heating,and strain-rate effects.1.2 To conduct a tension test by this standard,the specimenin a tensile cryostat is fully s
4、ubmerged in normal liquid helium(He I)and tested using crosshead displacement control at anominal strain rate of 103mm/mm/s or less.Tests using forcecontrol or high strain rates are not considered.1.3 This standard specifies methods for the measurement ofyield strength,tensile strength,elongation,an
5、d reduction ofarea.The determination of the Youngs modulus is treated inTest Method E111.NOTE1The boiling point of normal liquid helium(He I)at sea levelis 4.2 K(269C or 452.1F or 7.6R).It decreases with geographicelevation and is 4.0 K(269.2C or 452.5F or 7.2R)at the NationalInstitute of Standards
6、and Technology in Colorado,1677 m(5500 ft)above sea level.In this standard the temperature is designated 4 K.1.4 Values stated in SI units are treated as primary.Valuesstated in U.S.customary units are treated as secondary.1.5 This standard does not purport to address all of thesafety concerns,if an
7、y,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 regulatory limitations prior to use.See Section 5.2.Referenced Documents2.1 ASTM Standards:2A370 Test Methods and Definitions for M
8、echanical Testingof Steel ProductsE4 Practices for Force Verification of Testing MachinesE6 Terminology Relating to Methods of Mechanical TestingE8/E8M Test Methods for Tension Testing of Metallic Ma-terialsE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with Specifica
9、tionsE83 Practice for Verification and Classification of Exten-someter SystemsE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE111 Test Method for Youngs Modulus,Tangent Modulus,a
10、nd Chord ModulusE1012 Practice for Verification of Testing Frame and Speci-men Alignment Under Tensile and Compressive AxialForce Application3.Terminology3.1 Definitions of Terms Common to Mechanical Testing3.1.1 The definitions of mechanical testing terms that ap-pear in the Terminology E6 apply to
11、 this test method.Theseterms include bending strain,elongation,extensometer,force,gauge length,proportional limit,reduced section,reduction ofarea,stress-strain diagram,tensile strength,andYoungs modu-lus.3.1.2 In addition,the following common terms from Termi-nology E6 are defined:3.1.3 adjusted le
12、ngth of the reduced sectionthe length ofthe reduced section plus an amount calculated to compensatefor strain in the fillet region.3.1.4 discontinuous yielding,nin a uniaxial test,a hesita-tion or fluctuation of force observed at the onset of plasticdeformation,due to localized yielding.3.1.4.1 Disc
13、ussionThe stress-strain curve need not appearto be discontinuous.3.1.5 discontinuous yielding stress,ithe peak stress at theinitiation of the first measurable serration on the curve ofstress-versus-strain.3.1.5.1 DiscussionThe parameter iis a function of testvariables and is not a material constant.
14、1This test method is under the jurisdiction of ASTM Committee E28 onMechanical Testing and is the direct responsibility of Subcommittee E28.04 onUniaxial Testing.Current edition approved Nov.15,2016.Published February 2017.Originallyapproved in 1992.Last previous edition approved in 2009 as E1450 09
15、.DOI:10.1520/E1450-16.2For 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.Copyright ASTM International,100 Barr Harbor
16、 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 Technical Barriers to Trade(TBT)Committee.1 3.1.6 gauge length,nthe original length of that portion ofthe specimen over which strain,elongation,or change of lengthi
