1、Designation: D412 15aD412 16Standard 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 r
2、evision. 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 us
3、ed to evaluate the tensile (tension) properties of vulcanized thermoset rubbers andthermoplastic elastomers. These methods are not applicable to ebonite and similar hard, low elongation materials. The methodsappear as follows:Test Method ADumbbell and Straight Section SpecimensTest Method BCut Ring
4、SpecimensNOTE 1These two different methods do not produce identical results.1.2 The values stated in either SI or non-SI units shall be regarded separately as normative for this standard. The values in eachsystem may not be exact equivalents; therefore each system must be used independently, without
5、 combining values.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use
6、.2. Referenced Documents2.1 ASTM Standards:2D1349 Practice for RubberStandard Conditions for TestingD1566 Terminology Relating to RubberD3182 Practice for RubberMaterials, Equipment, and Procedures for Mixing Standard Compounds and Preparing StandardVulcanized SheetsD3183 Practice for RubberPreparat
7、ion of Pieces for Test Purposes from ProductsD3767 Practice for RubberMeasurement of DimensionsD4483 Practice for Evaluating Precision for Test Method Standards in the Rubber and Carbon Black Manufacturing IndustriesE4 Practices for Force Verification of Testing Machines2.2 ASTM Adjunct:Cut Ring Spe
8、cimens, Method B (D412)32.3 ISO Standards:ISO 37 Rubber, Vulcanized and Thermoplastic Determination of Tensile Stress-Strain Properties43. Terminology3.1 Definitions:3.1.1 tensile setthe extension remaining after a specimen has been stretched and allowed to retract in a specified manner,expressed as
9、 a percentage of the original length. (D1566)3.1.2 tensile set-after-breakthe tensile set measured by fitting the two broken dumbbell pieces together at the point of rupture.1 These test methods are under the jurisdiction of ASTM Committee D11 on Rubber and Rubber-like Materials and are the direct r
10、esponsibility of Subcommittee D11.10on Physical Testing.Current edition approved Dec. 1, 2015Nov. 1, 2016. Published January 2016December 2016. Originally approved in 1935. Last previous edition approved in 2015 asD412 15.D412 15a. DOI: 10.1520/D0412-15A.10.1520/D0412-16.2 For referencedASTM standar
11、ds, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 Detailed drawings are available from ASTM Headquarters, 100 Barr Harbor Drive, Conshoho
12、cken, PA 19428. Order Adjunct No. ADJD0412.4 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to t
13、he previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright
14、ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.3 tensile strengththe maximum tensile stress applied in stretching a specimen to rupture. (D1566)3.1.4 tensile stressa stress applied to stretch a test piece (specimen). (D1566)3.1.5 tensile s
15、tress at-given-elongationthe stress required to stretch the uniform cross section of a test specimen to a givenelongation. (D1566)3.1.6 thermoplastic elastomersa diverse family of rubberlike materials that unlike conventional vulcanized rubbers can beprocessed and recycled like thermoplastic materia
16、ls.3.1.7 ultimate elongationthe elongation at which rupture occurs in the application of continued tensile stress.3.1.8 yield pointthat point on the stress-strain curve, short of ultimate failure, where the rate of stress with respect to strain,goes through a zero value and may become negative. (D15
17、66)3.1.9 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 test pieces taken from the sample material and includes the preparationof the specime
18、ns and the testing of the specimens. Specimens may be in the shape of dumbbells, rings or straight pieces of uniformcross-sectional area.4.2 Measurements for tensile stress, tensile stress at a given elongation, tensile strength, yield point, and ultimate elongation aremade on specimens that have no
19、t been prestressed. Tensile stress, yield point, and tensile strength are based on the originalcross-sectional area of a uniform cross-section of the specimen.4.3 Measurement of tensile set is made after a previously unstressed specimen has been extended and allowed to retract by aprescribed procedu
20、re. Measurement of “set after break” is also described.5. Significance and Use5.1 All materials and products covered by these test methods must withstand tensile forces for adequate performance in certainapplications. These test methods allow for the measurement of such tensile properties. However,
21、tensile properties alone may notdirectly relate to the total end use performance of the product because of the wide range of potential performance requirementsin actual use.5.2 Tensile properties depend both on the material and the conditions of test (extension rate, temperature, humidity, specimeng
22、eometry, pretest conditioning, etc.); therefore materials should be compared only when tested under the same conditions.5.3 Temperature and rate of extension may have substantial effects on tensile properties and therefore should be controlled.These effects will vary depending on the type of materia
23、l being tested.5.4 Tensile set represents residual deformation which is partly permanent and partly recoverable after stretching and retraction.For this reason, the periods of extension and recovery (and other conditions of test) must be controlled to obtain comparable results.6. Apparatus6.1 Testin
24、g MachineTension tests shall be made on a power driven machine equipped to produce a uniform rate of gripseparation of 500 6 50 mm/min (20 6 2 in./min) for a distance of at least 750 mm (30 in.) (see Note 2). The testing machine shallhave both a suitable dynamometer and an indicating or recording sy
25、stem for measuring the applied force within 62 %. If thecapacity range cannot be changed for a test (as in the case of pendulum dynamometers) the applied force at break shall be measuredwithin 62 % of the full scale value, and the smallest tensile force measured shall be accurate to within 10 %. If
26、the dynamometeris of the compensating type for measuring tensile stress directly, means shall be provided to adjust for the cross-sectional area ofthe specimen. The response of the recorder shall be sufficiently rapid that the applied force is measured with the requisite accuracyduring the extension
27、 of the specimen to rupture. If the testing machine is not equipped with a recorder, a device shall be providedthat indicates, after rupture, the maximum force applied during extension. Testing machine systems shall be capable of measuringelongation of the test specimen in minimum increments of 10 %
28、.NOTE 2A rate 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 of dispute,the test shall be repeated and the rate of elongation shall be at 500 6 50 mm/min (20 6 2 in./min).6.2 Test Chamber for Elevated and Low TemperaturesThe test
29、 chamber shall conform with the following requirements:6.2.1 Air shall be circulated through the chamber at a velocity of 1 to 2 m/s (3.3 to 6.6 ft/s) at the location of the grips or spindlesand specimens maintained within 2C (3.6F) of the specified temperature.6.2.2 A calibrated sensing device shal
30、l be located near the grips or spindles for measuring the actual temperature.6.2.3 The chamber shall be vented to an exhaust system or to the outside atmosphere to remove fumes liberated at hightemperatures.D412 1626.2.4 Provisions shall be made for suspending specimens vertically near the grips or
31、spindles for conditioning prior to test. Thespecimens shall not touch each other or the sides of the chamber except for momentary contact when agitated by the circulatingair.6.2.5 Fast acting grips suitable for manipulation at high or low temperatures may be provided to permit placing dumbbells orst
32、raight specimens in the grips in the shortest time possible to minimize any change in temperature of the chamber.6.2.6 The dynamometer shall be suitable for use at the temperature of test or it shall be thermally insulated from the chamber.6.2.7 Provision shall be made for measuring the elongation o
33、f specimens in the chamber. If a scale is used to measure theextension between the bench-marks, the scale shall be located parallel and close to the grip path during specimen extension andshall be controlled from outside the chamber.6.3 MicrometerAdigital or analogue dial micrometer conforming to th
34、e requirements of Practice D3767 (ProcedureA). Ringspecimens are addressed in 14.10.6.4 Apparatus for Tensile Set TestThe testing machine described in 6.1 or an apparatus similar to that shown in Fig. 1 maybe used. A stop watch or other suitable timing device measuring in minute intervals for at lea
35、st 30 min, shall be provided. A scaleor other device shall be provided for measuring tensile set to within 1 %.FIG. 1 Apparatus for Tensile Set TestD412 1637. Selection of Test Specimens7.1 Consider the following information in making selections:7.1.1 Since anisotropy or grain directionality due to
36、flow introduced during processing and preparation may have an influenceon tensile properties, dumbbell or straight specimens should be cut so the lengthwise direction of the specimen is parallel to thegrain direction when this direction is known. Ring specimens normally give an average of with and a
37、cross the grain properties.7.1.2 Unless otherwise noted, thermoplastic rubber or thermoplastic elastomer specimens, or both, are to be cut from injectionmolded sheets or plaques with a thickness of 3.0 6 0.3 mm. Specimens of other thickness will not necessarily give comparableresults. Specimens are
38、to be tested in directions both parallel and perpendicular to the direction of flow in the mold. Sheet or plaquedimensions must be sufficient to do this.7.1.3 Ring specimens enable elongations to be measured by grip separation, but the elongation across the radial width of thering specimens is not u
39、niform. To minimize this effect the width of the ring specimens must be small compared to the diameter.7.1.4 Straight specimens tend to break in the grips if normal extension-to-break testing is conducted and should be used onlywhen it is not feasible to prepare another type of specimen. For obtaini
40、ng non-rupture stress-strain or material modulus properties,straight specimens are quite useful.7.1.5 The size of specimen type used will be determined by the material, test equipment and the sample or piece available fortest. A longer specimen may be used for rubbers having low ultimate elongation
41、to improve precision of elongation measurement.8. Calibration of the Testing Machine8.1 Calibrate the testing machine in accordance with Procedure A of Practices E4. If the dynamometer is of the strain-gaugetype, calibrate the tester at one or more forces in addition to the requirements in Sections
42、7 and 18 of Practices E4. Testers havingpendulum dynamometers may be calibrated as follows:8.1.1 Place one end of a dumbbell specimen in the upper grip 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 dumbbell specimenin the
43、 upper grip.8.1.3 Attach a hook to the lower end of the lower specimen grip mechanism.8.1.4 Suspend a known mass from the hook of the lower specimen grip mechanism in such a way as to permit the mass assemblyto temporarily rest on the lower testing machine grip framework or holder (see Note 3).8.1.5
44、 Start the grip separation motor or mechanism, as in normal testing, and allow it to run until the mass is freely suspendedby 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) withinspecified tol
45、erance, thoroughly inspect the testing machine for malfunction (for example, excess friction in bearings and othermoving parts). Ensure that the mass of the lower grip mechanism and the hook are included as part of the known mass.8.1.7 After machine friction or other malfunction has been removed, re
46、calibrate the testing machine at a minimum of threepoints using known masses to produce forces of approximately 10, 20 and 50 % of capacity. If pawls or rachets are used duringroutine testing, use them for calibration. Check for friction in the head by calibrating with the pawls up.NOTE 3It is advis
47、able to provide a means for preventing the known mass from falling to the floor in case the dumbbell should break.8.2 A rapid approximate calibration of the testing machine may be obtained by using a spring calibration device.9. Test Temperature9.1 Unless otherwise specified, the standard temperatur
48、e for testing 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 the relativehumidity at 50 6 5 % and condition the specimens for at least 24 h prior to testing. When testing at an
49、y other temperature isrequired use one of the temperatures listed in Practice D1349.9.2 For testing at temperatures above 23C (73.4F) preheat specimens for 10 6 2 min for Method A and for 6 6 2 min forMethod B. Place each specimen in the test chamber at intervals ahead of testing so that all specimens of a series will be in thechamber the same length of time. The preheat time at elevated temperatures must be limited to avoid additional vulcanization orthermal aging.9.3 For testing at temperatures below 23C (73.4F) condition the specimens at le
