1、Designation:D638-14INTERNATIONALStandard Test Method forTensile Properties of PlasticsThis standard is issued under the fixed designation D638;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in pare
2、ntheses indicates the year of last reapproval.Asuperscript epsilon(s)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.Scope*consider the precautions and limitations of this method found1.1 This
3、test method covers the determination of the tensilein Note 2 and Section 4 before considering these data forproperties of unreinforced and reinforced plastics in the formengineering design.of standard dumbbell-shaped test specimens when tested under1.5 The values stated in SI units are to be regarde
4、d asdefined conditions of pretreatment,temperature,humidity,andstandard.The values given in parentheses are for informationtesting machine speed.only.1.2 This test method is applicable for testing materials of1.6 This standard does not purport to address all of theany thickness up to 14 mm(0.55 in.)
5、.However,for testingsafety concerns,if any,associated with its use.It is thespecimens in the form of thin sheeting,including film less thanresponsibility of the user of this standard to establish appro-1.0 mm(0.04 in.)in thickness,ASTM standard D882 is thepriate safety and health practices and deter
6、mine the applica-preferred test method.Materials with a thickness greater thanbility of regulatory limitations prior to use.14 mm(0.55 in.)shall be reduced by machining.2.Referenced Documents1.3 This test method includes the option of determiningPoissons ratio at room temperature.2.1 ASTM Standards:
7、2D229 Test Methods for Rigid Sheet and Plate MaterialsNoTE 1-This standard and ISO 527-1 address the same subject matter,Used for Electrical Insulationbut differ in technical content.NoTE 2-This test method is not intended to cover precise physicalD412 Test Methods for Vulcanized Rubber and Thermopl
8、as-procedures.It is recognized that the constant rate of crosshead movementtic Elastomers-Tensiontype of test leaves much to be desired from a theoretical standpoint,thatD618 Practice for Conditioning Plastics for Testingwide differences may exist between rate of crosshead movement and rateD651 Test
9、 Method for Test for Tensile Strength of Moldedof strain between gage marks on the specimen,and that the testing speedsElectrical Insulating Materials(Withdrawn 1989)specified disguise important effects characteristic of materials in theD882 Test Method for Tensile Properties of Thin Plasticplastic
10、state.Further,it is realized that variations in the thicknesses of testspecimens,which are permitted by these procedures,produce variations inSheetingthe surface-volume ratios of such specimens,and that these variations mayD883 Terminology Relating to Plasticsinfluence the test results.Hence,where d
11、irectly comparable results areD1822 Test Method for Tensile-Impact Energy to Breakdesired,all samples should be of equal thickness.Special additional testsPlastics and Electrical Insulating Materialsshould be used where more precise physical data are needed.NoTE 3-This test method may be used for te
12、sting phenolic moldedD3039/D3039M Test Method for Tensile Properties of Poly-resin or laminated materials.However,where these materials are used asmer Matrix Composite Materialselectrical insulation,such materials should be tested in accordance withD4000 Classification System for Specifying Plastic
13、Materi-Test Methods D229 and Test Method D651.alsNoTE 4-For tensile properties of resin-matrix composites reinforcedD4066 Classification System for Nylon Injection and Extru-with oriented continuous or discontinuous high modulus 20-GPa(3.0 10-psi)fibers,tests shall be made in accordance with Testsio
14、n Materials(PA)Method D3039/D3039M.D5947 Test Methods for Physical Dimensions of SolidPlastics Specimens1.4 Test data obtained by this test method have been foundE4 Practices for Force Verification of Testing Machinesto be useful in engineering design.However,it is important to2 For referenced ASTM
15、standards,visit the ASTM website,www.astm.org,or This test method is under the jurisdiction of ASTM Committee D20 on Plasticscontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMand is the direct responsibility of Subcommittee D20.10 on Mechanical Properties.Standards volume infor
16、mation,refer to the standards Document Summary page onCurrent edition approved Dec.15,2014.Published March 2015.Originallythe ASTM website.approved in 1941.Last previous edition approved in 2010 as D638-10.DOI:3The last approved version of this historical standard is referenced on10.1520/D0638-14.ww
17、w.astm.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM Intemational,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States0D638-14E83 Practice for Verification and Classification of Exten-stress,temperature,previous history of specimen,etc
18、.However,stress-someter Systemsstrain curves for plastics,determined as described in this test method.E132 Test Method for Poissons Ratio at Room Temperaturealmost always show a linear region at low stresses,and a straight linedrawn tangent to this portion of the curve permits calculation of an elas
19、ticE691 Practice for Conducting an Interlaboratory Study tomodulus of the usually defined type.Such a constant is useful if itsDetermine the Precision of a Test Methodarbitrary nature and dependence on time,temperature,and similar factors2.2 ISO Standard:4are realized.ISO 527-1 Determination of Tens
20、ile Properties5.Apparatus3.Terminology5.1 Testing Machine-A testing machine of the constant-3.1 Definitions-Definitions of terms applying to this testrate-of-crosshead-movement type and comprising essentiallymethod appear in Terminology D883 and Annex A2.the following:5.1.1 Fixed Member-A fixed or e
21、ssentially stationary4.Significance and Usemember carrying one grip.4.1 This test method is designed to produce tensile property5.1.2 Movable Member-A movable member carrying adata for the control and specification of plastic materials.Thesesecond grip.data are also useful for qualitative characteri
22、zation and for5.1.3 Grips-Grips for holding the test specimen betweenresearch and development.the fixed member and the movable member of the testing4.2 Some material specifications that require the use of thismachine can be either the fixed or self-aligning type.test method,but with some procedural
23、modifications that take5.1.3.1 Fixed grips are rigidly attached to the fixed andprecedence when adhering to the specification.Therefore,it ismovable members of the testing machine.When this type ofadvisable to refer to that material specification before using thisgrip is used take extreme care to en
24、sure that the test specimentest method.Table 1 in Classification D4000 lists the ASTMis inserted and clamped so that the long axis of the testmaterials standards that currently exist.specimen coincides with the direction of pull through the4.3 Tensile properties are known to vary with specimencenter
25、 line of the grip assembly.preparation and with speed and environment of testing.5.1.3.2 Self-aligning grips are attached to the fixed andConsequently,where precise comparative results are desired,movable members of the testing machine in such a manner thatthese factors must be carefully controlled.
26、they will move freely into alignment as soon as any load isapplied so that the long axis of the test specimen will coincide4.4 It is realized that a material cannot be tested without alsowith the direction of the applied pull through the center line oftesting the method of preparation of that materi
27、al.Hence,whenthe grip assembly.Align the specimens as perfectly as possiblecomparative tests of materials per se are desired,exercise greatwith the direction of pull so that no rotary motion that maycare to ensure that all samples are prepared in exactly the sameinduce slippage will occur in the gri
28、ps;there is a limit to theway,unless the test is to include the effects of sampleamount of misalignment self-aligning grips will accommodate.preparation.Similarly.for referee purposes or comparisons5.1.3.3 The test specimen shall be held in such a way thatwithin any given series of specimens,care sh
29、all be taken toslippage relative to the grips is prevented insofar as possible.secure the maximum degree of uniformity in details ofGrip surfaces that are deeply scored or serrated with a patternpreparation,treatment,and handling.similar to those of a coarse single-cut file,serrations about 2.44.5 T
30、ensile properties provide useful data for plastics engi-mm(0.09 in.)apart and about 1.6 mm(0.06 in.)deep,haveneering design purposes.However,because of the high degreebeen found satisfactory for most thermoplastics.Finer serra-of sensitivity exhibited by many plastics to rate of straining andtions h
31、ave been found to be more satisfactory for harderenvironmental conditions.data obtained by this test methodplastics,such as the thermosetting materials.It is important thatcannot be considered valid for applications involving load-timethe serrations be kept clean and sharp.Should breaking in thescal
32、es or environments widely different from those of this testgrips occur,even when deep serrations or abraded specimenmethod.In cases of such dissimilarity,no reliable estimation ofsurfaces are used,other techniques shall be used.Otherthe limit of usefulness can be made for most plastics.Thistechnique
33、s that have been found useful,particularly withsensitivity to rate of straining and environment necessitatessmooth-faced grips,are abrading that portion of the surface oftesting over a broad load-time scale(including impact andthe specimen that will be in the grips,and interposing thincreep)and rang
34、e of environmental conditions if tensile prop-pieces of abrasive cloth,abrasive paper,or plastic,or rubber-erties are to suffice for engineering design purposes.coated fabric,commonly called hospital sheeting,between theNorE 5-Since the existence of a true elastic limit in plastics(as inspecimen and
35、 the grip surface.No.80 double-sided abrasivemany other organic materials and in many metals)is debatable,thepaper has been found effective in many cases.An open-meshpropriety of applying the term elastic modulusin its quoted,generallyfabric,in which the threads are coated with abrasive,has alsoacce
36、pted definition to describe the stiffnessor rigidityof a plastic hasbeen effective.Reducing the cross-sectional area of the speci-been seriously questioned.The exact stress-strain characteristics of plasticmen may also be effective.The use of special types of grips ismaterials are highly dependent o
37、n such factors as rate of application ofsometimes necessary to eliminate slippage and breakage in thegrips.4 Available from American National Standards Institute(ANSD).25 W.43rd St.5.1.4 Drive Mechanism-A drive mechanism for imparting4th Floor,New York,NY 10036,http:/www.ansi.org.a uniform,controlle
38、d velocity to the movable member withASTM ID638-14respect to the stationary member.This velocity is to be5.2.3 High-Extension Measurements-For making measure-regulated as specified in Section 8.ments at elongations greater than 20%,measuring techniques5.1.5 Load Indicator-A suitable load-indicating
39、mecha-with error no greater than+10%of the measured value arenism capable of showing the total tensile load carried by theacceptabletest specimen when held by the grips.This mechanism shall be5.3 Micrometers-Apparatus for measuring the width andessentially free of inertia lag at the specified rate o
40、f testing andthickness of the test specimen shall comply with the require-shall indicate the load with an accuracy of 1 of thements of Test Method D5947.indicated value,or better.The accuracy of the testing machineshall be verified in accordance with Practices E4.6.Test SpecimensNorE 6-Experience ha
41、s shown that many testing machines now in use6.1 Sheet,Plate,and Molded Plastics:are incapable of maintaining accuracy for as long as the periods between6.1.1 Rigid and Semirigid Plastics-The test specimen shallinspection recommended in Practices E4.Hence,it is recommended thatconform to the dimensi
42、ons shown in Fig.1.The Type Ieach machine be studied individually and verified as often as may befound necessary.It frequently will be necessary to perform this functionspecimen is the preferred specimen and shall be used wheredaily.sufficient material having a thickness of 7 mm(0.28 in.)or lessis a
43、vailable.The Type II specimen is recommended when a5.1.6 The fixed member,movable member,drivematerial does not break in the narrow section with the preferredmechanism,and grips shall be constructed of such materialsType I specimen.The Type V specimen shall be used whereand in such proportions that
44、the total elastic longitudinal strainonly limited material having a thickness of 4 mm(0.16 in.)orof the system constituted by these parts does not exceed 1 ofless is available for evaluation,or where a large number ofthe total longitudinal strain between the two gage marks on thespecimens are to be
45、exposed in a limited space(thermal andtest specimen at any time during the test and at any load up toenvironmental stability tests,etc.).The Type IV specimen isthe rated capacity of the machine.generally used when direct comparisons are required between5.1.7 Crosshead Extension Indicator-A suitable
46、extensionmaterials in different rigidity cases(that is,nonrigid andindicating mechanism capable of showing the amount ofsemirigid).The Type III specimen must be used for allchange in the separation of the grips,that is,crossheadmaterials with a thickness of greater than 7 mm(0.28 in.)butmovement.Thi
47、s mechanism shall be essentially free of inertialnot more than 14 mm(0.55 in.).lag at the specified rate of testing and shall indicate the6.1.2 Nonrigid Plastics-The test specimen shall conformcrosshead movement with an accuracy of 10%of theto the dimensions shown in Fig.1.The Type IV specimen shall
48、indicated value.be used for testing nonrigid plastics with a thickness of 4 mm(0.16 in.)or less.The Type III specimen must be used for all5.2 Extension Indicator(extensometer)-A suitable instru-materials with a thickness greater than 7 mm(0.28 in.)but notment shall be used for determining the distan
49、ce between twomore than 14 mm(0.55 in.).designated points within the gauge length of the test specimen6.1.3 Reinforced Composites-The test specimen for rein-as the specimen is stretched.For referee purposes,the exten-forced composites,including highly orthotropic laminates,someter must be set at the
50、 full gage length of the specimen,asshall conform to the dimensions of the Type I specimen shownshown in Fig.1.It is desirable,but not essential,that thisin Fig.1.instrument automatically record this distance,or any change in6.1.4 Preparation-Methods of preparing test specimensit.as a function of th
51、e load on the test specimen or of theinclude injection molding,machining operations,or dieelapsed time from the start of the test,or both.If only the lattercutting,from materials in sheet,plate,slab,or similar form.is obtained,load-time data must also be taken.This instrumentMaterials thicker than 1
52、4 mm(0.55 in.)shall be machined to 14shall be essentially free of inertia at the specified speed ofmm(0.55 in.)for use as Type III specimens.testing.Extensometers shall be classified and their calibrationperiodically verified in accordance with Practice E83NorE 7-Test results have shown that for som
53、e materials such as glasscloth.SMC,and BMC laminates,other specimen types should be5.2.1 Modulus-of-Elasticity Measurements-For modulus-considered to ensure breakage within the gage length of the specimen,asof-elasticity measurements,an extensometer with a maximummandated by 7.3.strain error of 0.00
54、02 mm/mm(in./in.)that automatically andNorE 8When preparing specimens from certain composite laminatessuch as woven roving,or glass cloth,exercise care in cutting thecontinuously records shall be used.An extensometer classifiedspecimens parallel to the reinforcement.The reinforcement will beby Pract
55、ice E83 as fulfilling the requirements of a B-2significantly weakened by cutting on a bias,resulting in lower laminateclassification within the range of use for modulus measure-properties,unless testing of specimens in a direction other than parallelments meets this requirement.with the reinforcemen
56、t constitutes a variable being studied.NorE 9-Specimens prepared by injection molding may have different5.2.2 Low-Extension Measurements-For elongation-at-tensile properties than specimens prepared by machining or die-cuttingyield and low-extension measurements(nominally 20%orbecause of the orientat
57、ion induced.This effect may be more pronouncedless),the same above extensometer,attenuated to 20%in specimens with narrow sections.extension,is acceptable.In any case,the extensometer system6.2 Rigid Tubes-The test specimen for rigid tubes shall bemust meet at least Class C(Practice E83)requirements
58、,whichas shown in Fig.2.The length,L,shall be as shown in the tableinclude a fixed strain error of 0.001 strain or 1.0%of thein Fig.2.A groove shall be machined around the outside of theindicated strain,whichever is greater.specimen at the center of its length so that the wall section afterASTMD638-
59、14ness.This groove shall consist of a straight section 57.2 mmMetal Plugs(2.25 in.)in length with a radius of 76 mm(3 in.)at each endjoining it to the outside diameter.Steel or brass plugs havingdiameters such that they will fit snugly inside the tube andhaving a length equal to the full jaw length
60、plus 25 mm(1 in.)89 mm,min.shall be placed in the ends of the specimens to prevent(3.50 in.)crushing.They can be located conveniently in the tube byseparating and supporting them on a threaded metal rod.Details of plugs and test assembly are shown in Fig.2.6.3 Rigid Rods-The test specimen for rigid
61、rods shall be asshown in Fig.3.The length,L,shall be as shown in the table51 mm,min.(2.00 in.)1.6 mm Rad.in Fig.3.A groove shall be machined around the specimen at(0.063 in.mm)the center of its length so that the diameter of the machined70 mm Radportion shall be 60%of the original nominal diameter.T
62、hisRS.(3.00 in.)groove shall consist of a straight section 57.2 mm(2.25 in.)inMachine toLlength with a radius of 76 mm(3 in.)at each end joining it to60%of57mmthe outside diameter.Original(2.25 in.)Nominal6.4 All surfaces of the specimen shall be free of visibleWall Thickness70 mm Rad.flaws,scratche
63、s,or imperfections.Marks left by coarse ma-Rs.(3.00 in.)chining operations shall be carefully removed with a fine file orabrasive,and the filed surfaces shall then be smoothed with1.6 mm Rad.(0.063 in.)abrasive paper(No.00 or finer).The finishing sanding strokes51 mm,min(2.00 in.)日号shall be made in
64、a direction parallel to the long axis of the test25mm(1.00in.)specimen.All flash shall be removed from a molded specimen,taking great care not to disturb the molded surfaces.Inmachining a specimen,undercuts that would exceed thedimensional tolerances shown in Fig.I shall be scrupulously89 mm,min.avo
65、ided.Care shall also be taken to avoid other common(3.50 in.)machining errors.6.5 If it is necessary to place gage marks on the specimen,this shall be done with a wax crayon or India ink that will notaffect the material being tested.Gage marks shall not bescratched,punched,or impressed on the specim
66、en.6.6 When testing materials that are suspected of anisotropy,DIMENSIONS OF TUBE SPECIMENSduplicate sets of test specimens shall be prepared,having theirlong axes respectively parallel with,and normal to,theStandard Length,L.Length of RadialTotal CalculatedNominal Wallsuspected direction of anisotr
67、opy.Sections,ThicknessMinimumof Specimen to BeUsed for 89-mm2R.S.Length of Specimen(3.5-in.)Jaws7.Number of Test Specimensmm(in.)7.1 Test at least five specimens for each sample in the case0.79(V2)13.9(0.547)350(13.80)381(15)of isotropic materials.1.2(4)17.0(0.670)354(13.92)381(15)1.6()19.6(0.773)35
68、6(14.02)381(15)7.2 For anisotropic materials,when applicable,test five2.4(2)24.0(0.946)361(14.20)381(15)3.2(%)27.7(1.091)364(14.34)381(15)specimens,normal to,and five parallel with,the principle axis4.8()33.9(1.333)370(14.58381(15)of anisotropy.6.4(4)39.0(1.536)376(14.79)400(15.75)7.9(e)43.5(1.714)3
69、80(14.96)400(15.75)7.3 Discard specimens that break at some flaw,or that break9.5(%)47.6(1.873)384(15.12)400(15.75)outside of the narrow cross-sectional test section(Fig.1,11.16)51.3(2.019)388(15.27)400(15.75)dimension L),and make retests,unless such flaws constitute12.7()54.7(2.154)391(15.40)419(16
70、.5)a variable to be studied.For jaws greater than 89 mm(3.5 in.),the standard length shall be increased byNoTE 10-Before testing,all transparent specimens should be inspectedtwice the length of the jaws minus 178 mm(7 in.).The standard length permits ain a polariscope.Those which show atypical or co
71、ncentrated strainslippage of approximately 6.4 to 12.7 mm(0.25 to 0.50 in.)in each jaw whilepatterns should be rejected,unless the effects of these residual strainsmaintaining the maximum length of the jaw grip.constitute a variable to be studied.FIG.2 Diagram Showing Location of Tube Tension Test Speci-8.Speed of Testingmens in Testing Machine8.1 Speed of testing shall be the relative rate of motion ofthe grips or test fixtures during the test.The rate of motion ofmachining shall be 60%of the original nominal wall thick-the driven grip or fixture when the testing machine is running
