1、Designation: D2671 13Standard Test Methods forHeat-Shrinkable Tubing for Electrical Use1This standard is issued under the fixed designation D2671; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number
2、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 These test methods cover the testing of heat-shrinkable
3、tubing used for electrical insulation. Materials used includepoly(vinyl chloride), polyolefins, fluorocarbon polymers, sili-cone rubber, and other plastic or elastomeric compounds.1.2 The procedures appear in the following sections:Procedure SectionsASTM MethodReferenceAdhesive Peel Strength 98 104B
4、rittleness Temperature 40 D746Color 55 and 56 D1535Color Stability 57 62 D1535Conditioning 7 D618Copper Stability 93Corrosion Testing 8995Dielectric Breakdown 20 25 D149Dimensions 8 13 D876Flammability 68 72 D876Fluid Resistance 6367Fungus Resistance 104 108Heat Resistance 4954Heat Shock 2630Low-Tem
5、perature Properties 3643Restricted Shrinkage 1419Selection of Test Specimens 6Secant Modulus 81 84 D882Storage Life 3135Specific Gravity 73 and 74 D792Stress Modulus 85 88 D412Tensile Strength and Ultimate Elongation 44 48 D412Thermal Endurance 96 and 97Volume Resistivity 75 78 D257Water Absorption
6、79 and 80 D570Melting Point 104 108 D34181.3 This is a fire-test-response standard.1.4 The values stated in inch-pound units are to be regardedas standard, except for temperature, which shall be expressedin degrees Celsius. The values given in parentheses aremathematical conversions to SI units that
7、 are provided forinformation only and are not considered standard.1.5 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 app
8、lica-bility of regulatory limitations prior to use. For specific hazardstatements, see Sections 5 and 68.2.NOTE 1These test methods are similar, but not identical to, those inIEC 606842 (see also Note 9).2. Referenced Documents2.1 ASTM Standards:2D149 Test Method for Dielectric Breakdown Voltage and
9、Dielectric Strength of Solid Electrical Insulating Materialsat Commercial Power FrequenciesD257 Test Methods for DC Resistance or Conductance ofInsulating MaterialsD412 Test Methods for Vulcanized Rubber and Thermoplas-tic ElastomersTensionD570 Test Method for Water Absorption of PlasticsD618 Practi
10、ce for Conditioning Plastics for TestingD746 Test Method for Brittleness Temperature of Plasticsand Elastomers by ImpactD792 Test Methods for Density and Specific Gravity (Rela-tive Density) of Plastics by DisplacementD876 Test Methods for Nonrigid Vinyl Chloride PolymerTubing Used for Electrical In
11、sulationD882 Test Method for Tensile Properties of Thin PlasticSheetingD1535 Practice for Specifying Color by the Munsell SystemD1711 Terminology Relating to Electrical InsulationD3418 Test Method for Transition Temperatures and En-thalpies of Fusion and Crystallization of Polymers byDifferential Sc
12、anning CalorimetryE176 Terminology of Fire Standards2.2 Other Documents:MIL-STD 104 Limits for Electrical Insulation Color31These test methods are under the jurisdiction of ASTM Committee D09 onElectrical and Electronic Insulating Materials and are the direct responsibility ofSubcommittee D09.07 on
13、Electrical Insulating Materials.Current edition approved Nov. 1, 2013. Published December 2013. Originallyapproved in 1967. Last previous edition approved in 2009 as D2671 09. DOI:10.1520/D2671-13.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service a
14、t serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from Standardization Documents Order Desk, Bldg. 4 Section D, 700Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.*A Summary of Changes section app
15、ears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Princi
16、ples for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1IEC Publication 216 Guide for the Determination of Ther-mal Endurance Properties of Electrical Insulating Materi-als4IEC Publication 6068
17、4 Specification for Flexible InsulatingSleeving4ISO 846 PlasticsEvaluation of the Action of Microorgan-isms43. Terminology3.1 Definitions:3.1.1 For definitions pertaining to electrical insulation, referto Terminology D1711.3.1.2 For definitions pertaining to fire standards, refer toTerminology E176.
18、3.1.3 heat-shrinkable tubing, ntubing that will reduce indiameter from an expanded size to a predetermined size by theapplication of heat.3.2 Definitions of Terms Specific to This Standard:3.2.1 brittleness temperature, nthe temperature at which50 % of the specimens fail when the specified number ar
19、etested using the apparatus and conditions specified.3.2.2 concentricity, nthe ratio expressed in percent of theminimum wall thickness to the maximum wall thickness.3.2.3 longitudinal change, nthe change in length, eitherpositive or negative, that occurs when the tubing is allowed tofreely recover a
20、t the recommended recovery temperature,expressed as a percentage of the as supplied or expandedlength.3.2.4 low-temperature flexibility, nthe resistance to crack-ing of tubing when wrapped around prescribed mandrels atspecified temperatures.3.2.5 restricted shrinkage, nshrinkage of the tubing at apr
21、escribed temperature over a specially designed mandrelwhose smallest diameter is greater than the fully shrunk sizeand whose largest diameter is less than the expanded size of thetubing.3.2.6 storage-life, heat-shrinkable tubing, nthe length oftime that the tubing will retain its specified expanded
22、andrecovered dimensions under storage at a specified temperature.4. Significance and Use4.1 These test methods include most of the important testsused to characterize heat-shrinkable tubing. They are intendedprimarily for, but not limited to, extruded heat-shrinkabletubing.4.2 It is acceptable to us
23、e variations in these test methods oralternate contemporary methods of measurement to determinethe values for the properties in this standard provided suchmethods ensure quality levels and measurement accuracy equalto or better than those prescribed herein. It is the responsibilityof the organizatio
24、ns using alternate test methods to be able todemonstrate this condition. In cases of dispute, the methodsspecified herein shall be used.NOTE 2Provision for alternate methods is necessary because of (1) thedesire to simplify procedures for specific applications without altering theresult, and (2) the
25、 desire to eliminate redundant testing and use datagenerated during manufacturing process control, including that generatedunder Statistical Process Control (SPC) conditions, using equipment andmethods other than those specified herein. An example would be the useof laser micrometers or optical comp
26、arators to measure dimensions.5. Hazards5.1 WarningLethal voltages are potentially present dur-ing this test. It is essential that the test apparatus, and allassociated equipment that is potentially electrically connectedto it, be properly designed and installed for safe operation.Solidly ground all
27、 electrically conductive parts that any personmight come in contact with during the test. Provide means foruse at the completion of any test to ground any parts which: (a)were at high voltage during the test; (b) have potentiallyacquired an induced charge during the test; or (c) could haveretained a
28、 charge even after disconnection of the voltagesource. Thoroughly instruct all operators in the proper way toconduct tests safely. When making high voltage tests, particu-larly in compressed gas or in oil, it is possible that the energyreleased at breakdown would be suffcient to result in fire,explo
29、sion, or rupture of the test chamber. Design testequipment, test chambers, and test specimens so as to minimizethe possibility of such occurrences and to eliminate thepossibility of personal injury. (See Section 23.)5.2 Flammable Solvents:5.2.1 Methyl ethyl ketone is a volatile, flammable solvent. I
30、tshall be handled in an area having good ventilation, such as alaboratory hood and away from sources of ignition. SeeSection 100.6. Selection of Test Specimens6.1 Select a sufficient number of pieces of tubing in suchmanner as to be representative of the shipment.6.2 Cut specimens, free of kinks, fr
31、om the sample selectedunder 6.1. Cut perpendicular to the longitudinal axis of thetubing and in such manner that the specimen has cleanly cutsquare edges.6.3 Unless otherwise stated, conduct tests on specimens inthe completely shrunk condition.7. Conditioning7.1 When specified, condition tubing in a
32、ccordance withPractice D618 using Procedure A, except that a conditioningtime of 4 h shall be used. In cases where tests are performed onspecimens in the shrunk state, condition the test specimensprior to testing, but after heat shrinking.DIMENSIONS8. Significance and Use8.1 Inside DiameterThe insid
33、e diameter of tubing beforeand after heat-shrinking is an important factor in selectingtubing of the proper size to slip easily over an object and toconform tightly after shrinkage.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.a
34、nsi.org.D2671 1328.2 Wall ThicknessWall thickness measurements are use-ful in providing design data and in calculating certain physicaland electrical properties of the tubing.8.3 ConcentricityIn some cases, a thin wall area, due tovariation in processing, will lead to equipment failure. It isimporta
35、nt, therefore, both in extrusion of the tubing, and itsexpansion prior to shrinkage in end-use, that concentricity beheld above a specified limit to ensure proper performance ofthe tubing.8.4 LengthThe length, both before and after heat-shrinking, is important in the determination of proper fit of t
36、hetubing in end-use.9. Apparatus9.1 MandrelsUse a series of steel rods suitable for inser-tion into the tubing including the tapered gages described underTest Methods D876.9.2 Micrometers, mandrel anvil and indicator set accurate toat least 0.001 in. or 0.02 mm.9.3 Steel Scale, graduated in164-in. o
37、r 0.5-mm divisions.9.4 Oven, forced-convection type, capable of maintainingtemperature to within 65C.10. Test Specimens10.1 Cut three straight lengths of expanded tubing, each 6in. (150 mm) long, from the sample as directed in 6.2 for eachtest performed.11. Procedure11.1 Measuring Inside Diameter:11
38、.1.1 Select a mandrel that will just fit into the specimenand insert the mandrel into the expanded tubing for a distanceof 1 in. (25 mm).NOTE 3If the tubing specimens have a tendency to adhere to themandrels during measurement of diameter, it is recommended that themandrels be coated with water or t
39、alc as a lubricant. However, cautionmust be exercised not to force the tubing on the mandrel, therebystretching the specimens.11.1.2 Using a machinists micrometer, measure the outsidediameter of the mandrel to the nearest 0.001 in. (0.02 mm).Record this as the expanded inside diameter.11.1.3 Place t
40、he specimen in an oven at the temperaturespecified as suitable for complete shrinkage for a period of timerecommended for shrinkage. Make provision for positioningthe specimen horizontally in the oven so that recovery can beeffected without restriction. If the tubing tends to becomesticky at the shr
41、inkage temperature, specimens can be laid intrays that have been powdered slightly with talc.11.1.4 At the end of the specified shrinkage time, removethe specimens from the oven and allow to cool to roomtemperature. Measure the inside diameter as described in11.1.1 and 11.1.2, recording this as the
42、recovered insidediameter.11.2 Measuring Wall Thickness:11.2.1 Measure the wall thickness of the expanded (assupplied) tubing using a micrometer. By means of a sufficientnumber of tests, locate the points on the wall corresponding tothe minimum and the maximum wall thickness, and recordthese measurem
43、ents to the nearest 0.001 in. (0.02 mm).11.2.2 Allow the specimens to recover under heat as de-scribed in 11.1.3 and 11.1.4. Measure the wall thickness asdescribed in 11.2.1 recording these as the recovered thick-nesses.11.3 Calculating ConcentricityFrom measurements ofminimum and maximum wall thick
44、ness made in accordancewith 11.2.1 and 11.2.2, calculate the concentricity (C) of theexpanded and recovered tubing respectively, using the follow-ing equation:C 5 100 M“/M! (1)where:M = maximum thickness, in. (mm), andM “ = minimum thickness, in. (mm).11.4 Measuring Length:11.4.1 Using the steel sca
45、le, measure the length to thenearest132 in. or 1 mm.11.4.2 Allow the specimens to recover under heat as de-scribed in 11.1.3 and 11.1.4. Measure the length after recovery.Record the length in the expanded and recovered state.11.5 Calculating Longitudinal ChangeFrom the measure-ments of expanded and
46、recovered length made in accordancewith 11.4.1 and 11.4.2, calculate the percent longitudinalchange using the following equation:Percent longitudinal change 5 100 L2L“!/L“ (2)where:L = recovered length, in. (mm), andL“ = expanded length, in. (mm).12. Report12.1 Report the following information:12.1.
47、1 Identification of the tubing,12.1.2 Inside diameter of the tubing in the expanded and inthe recovered state,12.1.3 Maximum and minimum wall thickness for eachspecimen in the expanded and in the recovered state,12.1.4 Length of each specimen in the expanded and recov-ered state,12.1.5 Percentage lo
48、ngitudinal change of each specimen(after recovery) based on the expanded state length,12.1.6 Concentricity of each specimen in the expanded andthe recovered state, and12.1.7 Time and temperature used for shrinkage of thetubing.13. Precision and Bias13.1 The overall estimates of the precision withinl
49、aboratories, (Sr) j, and the precision between laboratories,(Sr)j, are given in Table 1 for four selected materials. Theseestimates are based on a round robin of three specimens, eachD2671 133run in six laboratories.5No bias statement can be made due tothe lack of a standard reference material.RESTRICTED SHRINKAGE14. Significance and Use14.1 This test method covers the determination of the abilityof heat-shrinkable tubing to be shrunk on a specially designedmandrel without splitting or cracking. A voltage proof test isu
