1、Designation: D412 15Standard Test Methods forVulcanized Rubber and Thermoplastic ElastomersTension1This standard is issued under the fixed designation D412; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision.
2、 A number in parentheses 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 U.S. Department of Defense.1. Scope1.1 These test methods cover procedures used to ev
3、aluatethe tensile (tension) properties of vulcanized thermoset rubbersand thermoplastic elastomers. These methods are not appli-cable to ebonite and similar hard, low elongation materials.The methods appear as follows:Test Method ADumbbell and Straight Section SpecimensTest Method BCut Ring Specimen
4、sNOTE 1These two different methods do not produce identical results.1.2 The values stated in either SI or non-SI units shall beregarded separately as normative for this standard. The valuesin each system may not be exact equivalents; therefore eachsystem must be used independently, without combining
5、 values.1.3 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 appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Refe
6、renced Documents2.1 ASTM Standards:2D1349 Practice for RubberStandard Conditions for Test-ingD1566 Terminology Relating to RubberD3182 Practice for RubberMaterials, Equipment, and Pro-cedures for Mixing Standard Compounds and PreparingStandard Vulcanized SheetsD3183 Practice for RubberPreparation of
7、 Pieces for TestPurposes from ProductsD3767 Practice for RubberMeasurement of DimensionsD4483 Practice for Evaluating Precision for Test MethodStandards in the Rubber and Carbon Black ManufacturingIndustriesE4 Practices for Force Verification of Testing Machines2.2 ASTM Adjunct:Cut Ring Specimens, M
8、ethod B (D412)32.3 ISO Standards:ISO 37 Rubber, Vulcanized and Thermoplastic Determina-tion of Tensile Stress-Strain Properties43. Terminology3.1 Definitions:3.1.1 tensile setthe extension remaining after a specimenhas been stretched and allowed to retract in a specified manner,expressed as a percen
9、tage of the original length. (D1566)3.1.2 tensile set-after-breakthe tensile set measured byfitting the two broken dumbbell pieces together at the point ofrupture.3.1.3 tensile strengththe maximum tensile stress appliedin stretching a specimen to rupture. (D1566)3.1.4 tensile stressa stress applied
10、to stretch a test piece(specimen). (D1566)3.1.5 tensile stress at-given-elongationthe stress requiredto stretch the uniform cross section of a test specimen to agiven elongation. (D1566)3.1.6 thermoplastic elastomersa diverse family of rubber-like materials that unlike conventional vulcanized rubber
11、s canbe processed and recycled like thermoplastic materials.3.1.7 ultimate elongationthe elongation at which ruptureoccurs in the application of continued tensile stress.3.1.8 yield pointthat point on the stress-strain curve, shortof ultimate failure, where the rate of stress with respect tostrain,
12、goes through a zero value and may become negative.(D1566)1These test methods are under the jurisdiction of ASTM Committee D11 onRubber and are the direct responsibility of Subcommittee D11.10 on PhysicalTesting.Current edition approved Oct. 1, 2015. Published January 2016. Originallyapproved in 1935
13、. Last previous edition approved in 2013 as D412 06a (2013).DOI: 10.1520/D0412-15.2For 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 pag
14、e onthe ASTM website.3Detailed drawings are available from ASTM Headquarters, 100 Barr HarborDrive, Conshohocken, PA 19428. Order Adjunct No. ADJD0412.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036.Copyright ASTM International, 100 Barr Har
15、bor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.9 yield strainthe level of strain at the yield point.(D1566)3.1.10 yield stressthe level of stress at the yield point.(D1566)4. Summary of Test Method4.1 The determination of tensile properties starts with testpieces taken f
16、rom the sample material and includes thepreparation of the specimens and the testing of the specimens.Specimens may be in the shape of dumbbells, rings or straightpieces of uniform cross-sectional area.4.2 Measurements for tensile stress, tensile stress at a givenelongation, tensile strength, yield
17、point, and ultimate elonga-tion are made on specimens that have not been prestressed.Tensile stress, yield point, and tensile strength are based on theoriginal cross-sectional area of a uniform cross-section of thespecimen.4.3 Measurement of tensile set is made after a previouslyunstressed specimen
18、has been extended and allowed to retractby a prescribed procedure. Measurement of “set after break” isalso described.5. Significance and Use5.1 All materials and products covered by these test meth-ods must withstand tensile forces for adequate performance incertain applications. These test methods
19、allow for the measure-ment of such tensile properties. However, tensile propertiesalone may not directly relate to the total end use performanceof the product because of the wide range of potential perfor-mance requirements in actual use.5.2 Tensile properties depend both on the material and thecond
20、itions of test (extension rate, temperature, humidity, speci-men geometry, pretest conditioning, etc.); therefore materialsshould be compared only when tested under the same condi-tions.5.3 Temperature and rate of extension may have substantialeffects on tensile properties and therefore should be co
21、ntrolled.These effects will vary depending on the type of material beingtested.5.4 Tensile set represents residual deformation which ispartly permanent and partly recoverable after stretching andretraction. For this reason, the periods of extension andrecovery (and other conditions of test) must be
22、controlled toobtain comparable results.6. Apparatus6.1 Testing MachineTension tests shall be made on apower driven machine equipped to produce a uniform rate ofgrip separation of 500 6 50 mm/min (20 6 2 in./min) for adistance of at least 750 mm (30 in.) (see Note 2). The testingmachine shall have bo
23、th a suitable dynamometer and anindicating or recording system for measuring the applied forcewithin 62 %. If the capacity range cannot be changed for a test(as in the case of pendulum dynamometers) the applied force atbreak shall be measured within 62 % of the full scale value,and the smallest tens
24、ile force measured shall be accurate towithin 10 %. If the dynamometer is of the compensating typefor measuring tensile stress directly, means shall be provided toadjust for the cross-sectional area of the specimen. Theresponse of the recorder shall be sufficiently rapid that theapplied force is mea
25、sured with the requisite accuracy duringthe extension of the specimen to rupture. If the testing machineis not equipped with a recorder, a device shall be provided thatindicates, after rupture, the maximum force applied duringextension. Testing machine systems shall be capable of mea-suring elongati
26、on of the test specimen in minimum incrementsof 10 %.NOTE 2Arate of elongation of 1000 6 100 mm/min (40 6 4 in./min)may be used and notation of the speed made in the report. In case ofdispute, the test shall be repeated and the rate of elongation shall be at 5006 50 mm/min (20 6 2 in./min).6.2 Test
27、Chamber for Elevated and Low TemperaturesThetest chamber shall conform with the following requirements:6.2.1 Air shall be circulated through the chamber at avelocity of 1 to 2 m/s (3.3 to 6.6 ft/s) at the location of the gripsor spindles and specimens maintained within 2C (3.6F) of thespecified temp
28、erature.6.2.2 A calibrated sensing device shall be located near thegrips or spindles for measuring the actual temperature.6.2.3 The chamber shall be vented to an exhaust system orto the outside atmosphere to remove fumes liberated at hightemperatures.6.2.4 Provisions shall be made for suspending spe
29、cimensvertically near the grips or spindles for conditioning prior totest. The specimens shall not touch each other or the sides ofthe chamber except for momentary contact when agitated bythe circulating air.6.2.5 Fast acting grips suitable for manipulation at high orlow temperatures may be provided
30、 to permit placing dumbbellsor straight specimens in the grips in the shortest time possibleto minimize any change in temperature of the chamber.6.2.6 The dynamometer shall be suitable for use at thetemperature of test or it shall be thermally insulated from thechamber.6.2.7 Provision shall be made
31、for measuring the elongationof specimens in the chamber. If a scale is used to measure theextension between the bench-marks, the scale shall be locatedparallel and close to the grip path during specimen extensionand shall be controlled from outside the chamber.6.3 MicrometerA digital or analogue dia
32、l micrometerconforming to the requirements of Practice D3767 (ProcedureA). Ring specimens are addressed in 14.10.6.4 Apparatus for Tensile Set TestThe testing machinedescribed in 6.1 or an apparatus similar to that shown in Fig. 1may be used. A stop watch or other suitable timing devicemeasuring in
33、minute intervals for at least 30 min, shall beprovided. A scale or other device shall be provided formeasuring tensile set to within 1 %.7. Selection of Test Specimens7.1 Consider the following information in making selec-tions:7.1.1 Since anisotropy or grain directionality due to flowintroduced dur
34、ing processing and preparation may have anD412 152influence on tensile properties, dumbbell or straight specimensshould be cut so the lengthwise direction of the specimen isparallel to the grain direction when this direction is known.Ring specimens normally give an average of with and acrossthe grai
35、n properties.7.1.2 Unless otherwise noted, thermoplastic rubber or ther-moplastic elastomer specimens, or both, are to be cut frominjection molded sheets or plaques with a thickness of 3.0 60.3 mm. Specimens of other thickness will not necessarily givecomparable results. Specimens are to be tested i
36、n directionsboth parallel and perpendicular to the direction of flow in themold. Sheet or plaque dimensions must be sufficient to do this.7.1.3 Ring specimens enable elongations to be measured bygrip separation, but the elongation across the radial width ofthe ring specimens is not uniform. To minim
37、ize this effect thewidth of the ring specimens must be small compared to thediameter.7.1.4 Straight specimens tend to break in the grips if normalextension-to-break testing is conducted and should be usedonly when it is not feasible to prepare another type ofspecimen. For obtaining non-rupture stres
38、s-strain or materialmodulus properties, straight specimens are quite useful.7.1.5 The size of specimen type used will be determined bythe material, test equipment and the sample or piece availableFIG. 1 Apparatus for Tensile Set TestD412 153for test.Alonger specimen may be used for rubbers having lo
39、wultimate elongation to improve precision of elongation mea-surement.8. Calibration of the Testing Machine8.1 Calibrate the testing machine in accordance with Proce-dure A of Practices E4. If the dynamometer is of the strain-gauge type, calibrate the tester at one or more forces in additionto the re
40、quirements in Sections 7 and 18 of Practices E4.Testers having pendulum dynamometers may be calibrated asfollows:8.1.1 Place one end of a dumbbell specimen in the uppergrip of the testing machine.8.1.2 Remove the lower grip from the machine and attach it,by means of the gripping mechanism to the dum
41、bbell specimenin the upper grip.8.1.3 Attach a hook to the lower end of the lower specimengrip mechanism.8.1.4 Suspend a known mass from the hook of the lowerspecimen grip mechanism in such a way as to permit the massassembly to temporarily rest on the lower testing machine gripframework or holder (
42、see Note 3).8.1.5 Start the grip separation motor or mechanism, as innormal testing, and allow it to run until the mass is freelysuspended by the specimen in the upper grip.8.1.6 If the dial or scale does not indicate the force applied(or its equivalent in stress for a compensating type tester)withi
43、n specified tolerance, thoroughly inspect the testing ma-chine for malfunction (for example, excess friction in bearingsand other moving parts). Ensure that the mass of the lower gripmechanism and the hook are included as part of the knownmass.8.1.7 After machine friction or other malfunction has be
44、enremoved, recalibrate the testing machine at a minimum of threepoints using known masses to produce forces of approximately10, 20 and 50 % of capacity. If pawls or rachets are used duringroutine testing, use them for calibration. Check for friction inthe head by calibrating with the pawls up.NOTE 3
45、It is advisable to provide a means for preventing the knownmass from falling to the floor in case the dumbbell should break.8.2 A rapid approximate calibration of the testing machinemay be obtained by using a spring calibration device.9. Test Temperature9.1 Unless otherwise specified, the standard t
46、emperature fortesting shall be 23 6 2C (73.4 6 3.6F). Specimens shall beconditioned for at least 3 h when the test temperature is 23C(73.4F). If the material is affected by moisture, maintain therelative humidity at 50 6 5 % and condition the specimens forat least 24 h prior to testing. When testing
47、 at any othertemperature is required use one of the temperatures listed inPractice D1349.9.2 For testing at temperatures above 23C (73.4F) preheatspecimens for 10 6 2 min for MethodAand for 6 6 2 min forMethod B. Place each specimen in the test chamber at intervalsahead of testing so that all specim
48、ens of a series will be in thechamber the same length of time. The preheat time at elevatedtemperatures must be limited to avoid additional vulcanizationor thermal aging.9.3 For testing at temperatures below 23C (73.4F) condi-tion the specimens at least 10 min prior to testing.TEST METHOD ADUMBBELL
49、AND STRAIGHTSPECIMENS10. Apparatus10.1 DieThe shape and dimensions of the die for prepar-ing dumbbell specimens shall conform with those shown inFig. 2. The inside faces in the reduced section shall beperpendicular to the plane formed by the cutting edges andpolished for a distance of at least 5 mm (0.2 in.) from thecutting edge. The die shall at all times be sharp and free ofnicks (see 9.2).NOTE 4The condition of the die may be determined by investigatingthe rupture point on any series of broken (ruptured) specimens. Removesuch specimens from
