1、Designation: D648 16Standard Test Method forDeflection Temperature of Plastics Under Flexural Load inthe Edgewise Position1This standard is issued under the fixed designation D648; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, th
2、e year of last revision. 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. Scope*1.1 This test method cove
3、rs the determination of the tem-perature at which an arbitrary deformation occurs when speci-mens are subjected to an arbitrary set of testing conditions.1.2 This test method applies to molded and sheet materialsavailable in thicknesses of 3 mm (18 in.) or greater and whichare rigid or semirigid at
4、normal temperature.NOTE 1Sheet stock less than 3 mm (0.125 in.) but more than 1 mm(0.040 in.) in thickness may be tested by use of a composite sample havinga minimum thickness of 3 mm. The laminae must be of uniform stressdistribution. One type of composite specimen has been prepared bycementing the
5、 ends of the laminae together and then smoothing the edgeswith sandpaper. The direction of loading shall be perpendicular to theedges of the individual laminae.1.3 The values stated in SI units are to be regarded asstandard. The values given in parentheses are for informationonly.1.4 Some older mach
6、ines still use mercury-in-glass ther-mometers. (WarningMercury has been designated by manyregulatory agencies as a hazardous material that can causeserious medical issues. Mercury, or its vapor, has beendemonstrated to be hazardous to health and corrosive tomaterials. Caution should be taken when ha
7、ndling mercuryand mercury containing products. See the applicable productSafety Data Sheet (SDS) for additional information. Usersshould be aware that selling mercury and/or mercury contain-ing products into your state or country may be prohibited bylaw.1.5 This standard does not purport to address
8、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.NOTE 2The text of this standard references notes and footnote
9、s thatprovide explanatory material. These notes and footnotes (excluding thosein tables and figures) shall not be considered as requirements of thestandard.NOTE 3This standard and ISO 75-1 and ISO 75-2 address the samesubject matter, but differ in technical content, and results shall not becompared
10、between the two test methods.2. Referenced Documents2.1 ASTM Standards:2D618 Practice for Conditioning Plastics for TestingD883 Terminology Relating to PlasticsD4000 Classification System for Specifying Plastic Materi-alsD5947 Test Methods for Physical Dimensions of SolidPlastics SpecimensE1 Specifi
11、cation for ASTM Liquid-in-Glass ThermometersE77 Test Method for Inspection and Verification of Ther-mometersE608/E608M Specification for Mineral-Insulated, Metal-Sheathed Base Metal ThermocouplesE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE1137/E11
12、37M Specification for Industrial Platinum Resis-tance ThermometersE2251 Specification for Liquid-in-Glass ASTM Thermom-eters with Low-Hazard Precision Liquids2.2 ISO Standards:3ISO 75-1 PlasticsDetermination of Temperature of De-flection Under LoadPart 1: General Test MethodISO 75-2 PlasticsDetermin
13、ation of Temperature of De-flection Under LoadPart 2: Plastics and Ebonite2.3 NIST Document:4NBS Special Publication 250-221This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.30 on Thermal Properties.Current edition approv
14、ed April 1, 2016. Published April 2016. Originallyapproved in 1941. Last previous edition approved in 2007 as D648 - 07, which waswithdrawn January 2016 and reinstated in April 2016. DOI: 10.1520/D0648-16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer S
15、ervice at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.4Mangum, B. W., “Platinum Res
16、istance Thermometer Calibration,” NBS SpecialPublication 250-22, 1987. Available from National Institute of Standards andTechnology, Gaithersburg, MD.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken,
17、PA 19428-2959. United States13. Terminology3.1 GeneralThe definitions of plastics used in this testmethod are in accordance with Terminology D883 unlessotherwise indicated.4. Summary of Test Method4.1 A bar of rectangular cross section is tested in theedgewise position as a simple beam with the load
18、 applied at itscenter to give maximum fiber stresses of 0.455 MPa (66 psi) or1.82 MPa (264 psi) (Note 4). The specimen is immersed underload in a heat-transfer medium provided with a means ofraising the temperature at 2 6 0.2C/min. The temperature ofthe medium is measured when the test bar has defle
19、cted 0.25mm (0.010 in.). This temperature is recorded as the deflectiontemperature under flexural load of the test specimen.NOTE 4Around robin has been conducted that showed that there is noadvantage to using higher loads when measuring deflection temperature ofpresent-day plastics with present-day
20、instruments.5. Significance and Use5.1 This test is particularly suited to control and develop-ment work. Data obtained by this test method shall not be usedto predict the behavior of plastic materials at elevated tempera-tures except in applications in which the factors of time,temperature, method
21、of loading, and fiber stress are similar tothose specified in this test method. The data are not intendedfor use in design or predicting endurance at elevated tempera-tures.5.2 For many materials, there may be a specification thatrequires the use of this test method, but with some proceduralmodifica
22、tions that take precedence when adhering to thespecification. Therefore, it is advisable to refer to that materialspecification before using this test method. Refer to Table 1 inClassification D4000, which lists the ASTM material standardsthat currently exist.6. Interferences6.1 The results of the t
23、est are dependent on the rate of heattransfer between the fluid and the specimen and the thermalconductivity of the fluid.6.2 The results of this test are dependent on the measuredwidth and depth of the specimen and the final deflection atwhich the deflection temperature is determined.6.3 The type o
24、f mold and the molding process used toproduce test specimens affects the results obtained in this test.Molding conditions shall be in accordance with the standardfor that material or shall be agreed upon by the cooperatinglaboratories.6.4 Results of testing are affected by the design of the testequi
25、pment. The test span (either 100 mm or 101.6 mm) willinfluence the resultant measurement. Instrumentation equippedwith metal clips or other types of auxiliary supports designedto maintain specimens perpendicular to the applied load willaffect the test results if the pressure is sufficient to restric
26、t thedownward motion of the specimen at its center.7. Apparatus7.1 The apparatus shall be constructed essentially as shownin Fig. 1 and shall consist of the following:7.1.1 Specimen Supports, metal supports, allowing the loadto be applied on top of the specimen vertically and midwaybetween the suppo
27、rts, which shall be separated by a distance,defined in 7.1.1.1 or 7.1.1.2. The contact edges of the supportsand of the piece by which load is applied shall be rounded toa radius of 3 6 0.2 mm (0.118 6 0.008 in.).7.1.1.1 Method A101.6 6 0.5 mm (4.0 6 0.02 in.).7.1.1.2 Method B100.0 6 0.5 mm (3.937 6
28、0.020 in.).7.1.2 Immersion BathChoose a suitable liquid heat-transfer medium (Note 5) in which the specimen shall beimmersed, which will not affect the specimen. It shall bewell-stirred during the test and shall be provided with a meansof raising the temperature at a uniform rate of 2 6 0.2C/min.Thi
29、s heating rate shall be considered to be met if, over every5-min interval during the test, the temperature of the bath shallrise 10 6 1C at each specimen location.NOTE 5Mineral oil is considered safe from ignition to 115C. Siliconeoils may be heated to about 260C for short periods of time. For still
30、higher temperatures, special heat-transfer media should be used. Improvedperformance with longer oil life may be obtained by the use of CO2orother inert gas to isolate the oil surface from the atmosphere.7.1.3 Deflection Measurement Device, suitable for measur-ing specimen deflection of at least 0.2
31、5 mm (0.010 in.). It shallbe readable to 0.01 mm (0.0005 in.) or better. Dial gauges orany other indicating or recording device, including electricdisplacement sensing apparatus, are acceptable.7.1.4 WeightsA set of weights of suitable sizes so that thespecimen are loaded to a fiber stress of 0.455
32、MPa (66 psi) 62.5 % or 1.82 MPa (264 psi) 6 2.5 %. The mass of the rod thatapplies the testing force shall be determined and included aspart of the total load. If a dial gauge is used, the force exertedby its spring shall be determined and shall be included as partof the load (Note 9). Calculate the
33、 testing force and the massthat must be added to achieve the desired stress as follows:F 5 2Sbd2/3L (1)F15 F/9.80665D648 162mw5 F 2 Fs!/9.80665 2 mrwhere:F = load, N,F1= load, kgf,S = fiber stress in the specimen (0.455 MPa or 1.82 MPa),b = width of specimen, mm,d = depth of specimen, mm,L = distanc
34、e between supports, (101.6 mmMethod A, or100 mmMethod B), see 7.1.1.1 and 7.1.1.2.mw= added mass, kg,Fs= force exerted by any spring-loaded componentinvolved, N; this is a positive value if the thrust of thespring is towards the test specimen (downwards), or anegative value if the thrust of the spri
35、ng is opposingthe descent of the rod, or zero if no such component isinvolved, andmr= mass of the rod that applies the testing force to thespecimen, kg.NOTE 6In some designs of this apparatus, the spring force of the dialgauge is directed upward (opposite the direction of specimen loading),which red
36、uces the net force applied to the specimen. In other designs, thespring force of the dial gauge acts downward (in the direction of specimenloading), which increases the net force applies to the specimen. The massapplied to the loading rod must be adjusted accordingly (increased forupward dial force
37、and decreased for downward dial force) to compensate.Since the force exerted by the spring in certain dial gauges variesconsiderably over the stroke, this force should be measured in that part ofthe stroke that is to be used. Suggested procedures to determine the totalload required to correct for th
38、e force of the dial gauge spring are given inAppendix X1 and Appendix X2. Other procedures may be used ifequivalent results are obtained. Appendix X3 provides a method ofdetermining the spring force, uniformity of the force in the gauges testmeasurement range, and whether the gauge is contaminated a
39、nd sticking.7.1.5 Temperature Measurement System7.1.5.1 Digital Indicating SystemConsisting of athermocouple, resistance thermometer (RTD), and so forth, asthe sensor, together with associated conditioning, conversion,and readout instrumentation adequate to cover the range beingtested. The sensor an
40、d related electronics shall be accurate to atleast 60.5C. Thermocouples shall comply with the require-ments of Specification E608/E608M. Resistance thermometersshall comply with the requirements of Specification E1137/E1137M.7.1.5.2 ThermometerOlder systems still in existence use athermometer for te
41、mperature measurement at each individualtest station. The thermometer shall be one of the following, orits equivalent, as prescribed in Specification E1: Thermometer1C or 2C, having ranges from 20 to 150C or 5 to 300Crespectively, whichever temperature range is most suitable.Liquid-in-glass thermome
42、ters shall be calibrated for the depthof immersion in accordance with Test Method E77.FIG. 1 Apparatus for Deflection Temperature TestD648 163NOTE 7Consult Specification E2251 for suitable alternatives tomercury-in-glass thermometers.7.2 Micrometers shall meet the requirements of Test Meth-ods D5947
43、 and be calibrated in accordance with that testmethod.8. Sampling8.1 Sample in a statistically acceptable manner. Whensamples are taken from a production lot or process, the processshall be in a state of statistical control.9. Test Specimen9.1 At least two test specimens shall be used to test eachsa
44、mple at each fiber stress. The specimen shall be 127 mm (5in.) in length, 13 mm (12 in.) in depth by any width from 3 mm(18 in.) to 13 mm (12 in.).NOTE 8Tolerances on the depth and width dimensions (for highlyreproducible work) should be of the order of 60.13 mm (0.005 in.) alongthe length of the sp
45、ecimen.NOTE 9The test results obtained on specimens approaching 13 mm inwidth may be 2 to 4C above those obtained from 4 mm or narrower testspecimens because of poor heat transfer through the specimen.9.2 The specimens shall have smooth flat surfaces free fromsaw cuts, excessive sink marks, or flash
46、.9.3 Molding conditions shall be in accordance with thespecification for that material or shall be agreed upon by thecooperating laboratories. Discrepancies in test results due tovariations in molding conditions are often minimized byannealing the test specimens before the test. Since differentmater
47、ials require different annealing conditions, annealingprocedures shall be employed only if required by the materialstandard or if agreed upon by the cooperating laboratories.10. Preparation of Apparatus10.1 The apparatus shall be arranged so that the deflectionof the specimen at midspan is measured
48、by the deflectionmeasurement device described in 7.1.3. It is acceptable if theapparatus is arranged to shut off the heat automatically andsound an alarm or record the temperature when the specificdeflection has been reached. Sufficient heat transfer liquid shallbe used to cover the sensing end of t
49、he temperature measuringdevice to the point specified in their calibration.NOTE 10It is desirable to have a means to cool the bath in order toreduce the time required to lower the temperature of the bath after the testhas been completed. This may be accomplished by using a cooling coilinstalled in the bath, or an external heat transfer system that passes the hotoil through it. If the rate of temperature rise of the oil is adversely affectedby the presence of residual coolant in the coils, the coolant should bepurged prior to starting the nex
