1、Designation: D638 10Standard Test Method forTensile Properties of Plastics1This 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 parentheses
2、 indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 This test method covers the determination of the tensileproperties of unre
3、inforced and reinforced plastics in the formof standard dumbbell-shaped test specimens when tested underdefined conditions of pretreatment, temperature, humidity, andtesting machine speed.1.2 This test method can be used for testing materials of anythickness up to 14 mm (0.55 in.). However, for test
4、ingspecimens in the form of thin sheeting, including film less than1.0 mm (0.04 in.) in thickness, Test Methods D882 is thepreferred test method. Materials with a thickness greater than14 mm (0.55 in.) must be reduced by machining.1.3 This test method includes the option of determiningPoissons ratio
5、 at room temperature.NOTE 1This test method and ISO 527-1 are technically equivalent.NOTE 2This test method is not intended to cover precise physicalprocedures. It is recognized that the constant rate of crosshead movementtype of test leaves much to be desired from a theoretical standpoint, thatwide
6、 differences may exist between rate of crosshead movement and rateof strain between gage marks on the specimen, and that the testing speedsspecified disguise important effects characteristic of materials in theplastic state. Further, it is realized that variations in the thicknesses of testspecimens
7、, which are permitted by these procedures, produce variations inthe surface-volume ratios of such specimens, and that these variations mayinfluence the test results. Hence, where directly comparable results aredesired, all samples should be of equal thickness. Special additional testsshould be used
8、where more precise physical data are needed.NOTE 3This test method may be used for testing phenolic moldedresin or laminated materials. However, where these materials are used aselectrical insulation, such materials should be tested in accordance withTest Methods D229 and Test Method D651.NOTE 4For
9、tensile properties of resin-matrix composites reinforcedwith oriented continuous or discontinuous high modulus 20-GPa3.0 3 106-psi) fibers, tests shall be made in accordance with TestMethod D3039/D3039M.1.4 Test data obtained by this test method are relevant andappropriate for use in engineering des
10、ign.1.5 The values stated in SI units are to be regarded asstandard. The values given in parentheses are for informationonly.1.6 This 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 app
11、ro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D229 Test Methods for Rigid Sheet and Plate MaterialsUsed for Electrical InsulationD412 Test Methods for Vulcanized Rubber and Thermo-plastic Elast
12、omersTensionD618 Practice for Conditioning Plastics for TestingD651 Method of Test for Tensile Strength of MoldedElectrical Insulating Material3D882 Test Method for Tensile Properties of Thin PlasticSheetingD883 Terminology Relating to PlasticsD1822 Test Method for Tensile-Impact Energy to BreakPlas
13、tics and Electrical Insulating MaterialsD3039/D3039M Test Method for Tensile Properties ofPolymer Matrix Composite MaterialsD4000 Classification System for Specifying Plastic Materi-alsD4066 Classification System for Nylon Injection and Ex-trusion Materials (PA)D5947 Test Methods for Physical Dimens
14、ions of SolidPlastics SpecimensE4 Practices for Force Verification of Testing MachinesE83 Practice for Verification and Classification of Exten-someter SystemsE132 Test Method for Poissons Ratio at Room Tempera-ture1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is t
15、he direct responsibility of Subcommittee D20.10 on Mechanical Properties.Current edition approved May 15, 2010. Published June 2010. Originallyapproved in 1941. Last previous edition approved in 2008 as D638 - 08. DOI:10.1520/D0638-10.2For referenced ASTM standards, visit the ASTM website, www.astm.
16、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.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.1*A Summary of Changes section
17、appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.E691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method2.2 ISO Standard:4ISO 527-1 Determination of Tensile P
18、roperties3. Terminology3.1 DefinitionsDefinitions of terms applying to this testmethod appear in Terminology D883 and Annex A2.4. Significance and Use4.1 This test method is designed to produce tensile propertydata for the control and specification of plastic materials. Thesedata are also useful for
19、 qualitative characterization and forresearch and development. For many materials, there may be aspecification that requires the use of this test method, but withsome procedural modifications that take precedence whenadhering to the specification. Therefore, it is advisable to referto that material
20、specification before using this test method.Table 1 in Classification D4000 lists the ASTM materialsstandards that currently exist.4.2 Tensile properties may vary with specimen preparationand with speed and environment of testing. Consequently,where precise comparative results are desired, these fac
21、torsmust be carefully controlled.4.2.1 It is realized that a material cannot be tested withoutalso testing the method of preparation of that material. Hence,when comparative tests of materials per se are desired, thegreatest care must be exercised to ensure that all samples areprepared in exactly th
22、e same way, unless the test is to includethe effects of sample preparation. Similarly, for referee pur-poses or comparisons within any given series of specimens,care must be taken to secure the maximum degree of unifor-mity in details of preparation, treatment, and handling.4.3 Tensile properties ma
23、y provide useful data for plasticsengineering design purposes. However, because of the highdegree of sensitivity exhibited by many plastics to rate ofstraining and environmental conditions, data obtained by thistest method cannot be considered valid for applications involv-ing load-time scales or en
24、vironments widely different fromthose of this test method. In cases of such dissimilarity, noreliable estimation of the limit of usefulness can be made formost plastics. This sensitivity to rate of straining and environ-ment necessitates testing over a broad load-time scale (includ-ing impact and cr
25、eep) and range of environmental conditions iftensile properties are to suffice for engineering design pur-poses.NOTE 5Since the existence of a true elastic limit in plastics (as inmany other organic materials and in many metals) is debatable, thepropriety of applying the term “elastic modulus” in it
26、s quoted, generallyaccepted definition to describe the “stiffness” or “rigidity” of a plastic hasbeen seriously questioned. The exact stress-strain characteristics of plasticmaterials are highly dependent on such factors as rate of application ofstress, temperature, previous history of specimen, etc
27、. However, stress-strain curves for plastics, determined as described in this test method,almost always show a linear region at low stresses, and a straight linedrawn tangent to this portion of the curve permits calculation of an elasticmodulus of the usually defined type. Such a constant is useful
28、if itsarbitrary nature and dependence on time, temperature, and similar factorsare realized.5. Apparatus5.1 Testing MachineA testing machine of the constant-rate-of-crosshead-movement type and comprising essentiallythe following:5.1.1 Fixed MemberA fixed or essentially stationarymember carrying one
29、grip.5.1.2 Movable MemberA movable member carrying asecond grip.5.1.3 GripsGrips for holding the test specimen betweenthe fixed member and the movable member of the testingmachine can be either the fixed or self-aligning type.5.1.3.1 Fixed grips are rigidly attached to the fixed andmovable members o
30、f the testing machine. When this type ofgrip is used extreme care should be taken to ensure that the testspecimen is inserted and clamped so that the long axis of thetest specimen coincides with the direction of pull through thecenter line of the grip assembly.5.1.3.2 Self-aligning grips are attache
31、d to the fixed andmovable members of the testing machine in such a manner thatthey will move freely into alignment as soon as any load isapplied so that the long axis of the test specimen will coincidewith the direction of the applied pull through the center line ofthe grip assembly. The specimens s
32、hould be aligned as per-fectly as possible with the direction of pull so that no rotarymotion that may induce slippage will occur in the grips; thereis a limit to the amount of misalignment self-aligning grips willaccommodate.5.1.3.3 The test specimen shall be held in such a way thatslippage relativ
33、e to the grips is prevented insofar as possible.Grip surfaces that are deeply scored or serrated with a patternsimilar to those of a coarse single-cut file, serrations about 2.4mm (0.09 in.) apart and about 1.6 mm (0.06 in.) deep, havebeen found satisfactory for most thermoplastics. Finer serra-tion
34、s have been found to be more satisfactory for harderplastics, such as the thermosetting materials. The serrationsshould be kept clean and sharp. Breaking in the grips mayoccur at times, even when deep serrations or abraded specimensurfaces are used; other techniques must be used in these cases.Other
35、 techniques that have been found useful, particularly withsmooth-faced grips, are abrading that portion of the surface ofthe specimen that will be in the grips, and interposing thinpieces of abrasive cloth, abrasive paper, or plastic, or rubber-coated fabric, commonly called hospital sheeting, betwe
36、en thespecimen and the grip surface. No. 80 double-sided abrasivepaper has been found effective in many cases. An open-meshfabric, in which the threads are coated with abrasive, has alsobeen effective. Reducing the cross-sectional area of the speci-men may also be effective. The use of special types
37、 of grips issometimes necessary to eliminate slippage and breakage in thegrips.5.1.4 Drive MechanismA drive mechanism for impartingto the movable member a uniform, controlled velocity withrespect to the stationary member, with this velocity to beregulated as specified in Section 8.4Available from Am
38、erican National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.D638 1025.1.5 Load IndicatorA suitable load-indicating mecha-nism capable of showing the total tensile load carried by thetest specimen when held by the grips. This mechanism shall beessentia
39、lly free of inertia lag at the specified rate of testing andshall indicate the load with an accuracy of 61 % of theindicated value, or better. The accuracy of the testing machineshall be verified in accordance with Practices E4.NOTE 6Experience has shown that many testing machines now in useare inca
40、pable of maintaining accuracy for as long as the periods betweeninspection recommended in Practices E4. Hence, it is recommended thateach machine be studied individually and verified as often as may befound necessary. It frequently will be necessary to perform this functiondaily.5.1.6 The fixed memb
41、er, movable member, drive mecha-nism, and grips shall be constructed of such materials and insuch proportions that the total elastic longitudinal strain of thesystem constituted by these parts does not exceed 1 % of thetotal longitudinal strain between the two gage marks on the testspecimen at any t
42、ime during the test and at any load up to therated capacity of the machine.5.1.7 Crosshead Extension IndicatorA suitable extensionindicating mechanism capable of showing the amount ofchange in the separation of the grips, that is, crossheadmovement. This mechanism shall be essentially free of inerti
43、allag at the specified rate of testing and shall indicate thecrosshead movement with an accuracy of 610 % of theindicated value.5.2 Extension Indicator (extensometer)A suitable instru-ment shall be used for determining the distance between twodesignated points within the gage length of the test spec
44、imen asthe specimen is stretched. For referee purposes, the extensom-eter must be set at the full gage length of the specimen, asshown in Fig. 1. It is desirable, but not essential, that thisinstrument automatically record this distance, or any change init, as a function of the load on the test spec
45、imen or of theelapsed time from the start of the test, or both. If only the latteris obtained, load-time data must also be taken. This instrumentshall be essentially free of inertia at the specified speed oftesting. Extensometers shall be classified and their calibrationperiodically verified in acco
46、rdance with Practice E83.5.2.1 Modulus-of-Elasticity MeasurementsFor modulus-of-elasticity measurements, an extensometer with a maximumstrain error of 0.0002 mm/mm (in./in.) that automatically andcontinuously records shall be used. An extensometer classifiedby Practice E83 as fulfilling the requirem
47、ents of a B-2classification within the range of use for modulus measure-ments meets this requirement.5.2.2 Low-Extension MeasurementsFor elongation-at-yield and low-extension measurements (nominally 20 % orless), the same above extensometer, attenuated to 20 % exten-sion, may be used. In any case, t
48、he extensometer system mustmeet at least Class C (Practice E83) requirements, whichinclude a fixed strain error of 0.001 strain or 61.0 % of theindicated strain, whichever is greater.5.2.3 High-Extension MeasurementsFor making mea-surements at elongations greater than 20 %, measuring tech-niques wit
49、h error no greater than 610 % of the measured valueare acceptable.5.3 MicrometersApparatus for measuring the width andthickness of the test specimen shall comply with the require-ments of Test Method D5947.6. Test Specimens6.1 Sheet, Plate, and Molded Plastics:6.1.1 Rigid and Semirigid PlasticsThe test specimen shallconform to the dimensions shown in Fig. 1. The Type Ispecimen is the preferred specimen and shall be used wheresufficient material having a thickness of 7 mm (0.28 in.) or lessis available. The Type II specimen may be used when amaterial does not b
