1、Designation: D349 07D349 13 An American National StandardStandard Test Methods forLaminated Round Rods Used for Electrical Insulation1This standard is issued under the fixed designation D349; the number immediately following the designation indicates the year oforiginal adoption or, in the case of r
2、evision, the 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.1. Scope*1.1 These test methods cover the procedures for testing rigid round rods used in electrical insulati
3、on. These round rods includemany types made from fibrous sheets of basic materials, such as cellulose, glass, or nylon in the form of paper, woven fabrics, ormats, bonded together by natural or synthetic resins, or by adhesives. Such round rods include vulcanized fiber and thermosettinglaminates as
4、well as round rods made from cast, molded, or extruded natural or synthetic resins, with or without fillers orreinforcing materials.1.2 The procedures appear in the following sections:SectionCompressive strength (axial) 20 25Density 28 30Dielectric strength 31 39Flexural strength 13 19Tensile streng
5、th 7 12Water absorption 26-27SectionCompressive strength (axial) 20 25Density 28 30Dielectric strength 31 39Flexural strength 13 19Tensile strength 7 12Water absorption 26-271.3 The values stated in inch-pound units are to be regarded as the standard.1.4 This standard does not purport to address all
6、 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. For a specific warning statement see 36.2.2. Referenced Documents
7、2.1 ASTM Standards:2D149 Test Method for Dielectric Breakdown Voltage and Dielectric Strength of Solid Electrical Insulating Materials atCommercial Power FrequenciesD570 Test Method for Water Absorption of PlasticsD668 Test Methods of Measuring Dimensions of Rigid Rods and Tubes Used for Electrical
8、InsulationD792 Test Methods for Density and Specific Gravity (Relative Density) of Plastics by DisplacementD1711 Terminology Relating to Electrical InsulationD6054 Practice for Conditioning Electrical Insulating Materials for Testing (Withdrawn 2012)33. Terminology3.1 DefinitionsUse Terminology D171
9、1 for definitions of terms used in these test methods and associated with electrical orelectronic insulation materials.1 These test methods are under the jurisdiction ofASTM Committee D09 on Electrical and Electronic Insulating Materials and are the direct responsibility of SubcommitteeD09.07 on Fle
10、xible and Rigid Insulating Materials.Current edition approved Feb. 1, 2007Nov. 1, 2013. Published February 2007November 2013. Originally approved in 1932. Last previous edition approved in 20042007as D349 99D349 07.(2004). DOI: 10.1520/D0349-07.10.1520/D0349-13.2 For referencedASTM standards, visit
11、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 The last approved version of this historical standard is referenced on www.astm.org.This document
12、 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 the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appr
13、opriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United Sta
14、tes14. Selection of Test Specimens4.1 Specimens for tests shall be selected from portions of material that are free of obvious defects unless the purpose of the testis to evaluate the effect of these defects.5. Conditioning5.1 In order to eliminate the effects of previous history of humidity exposur
15、e and to obtain reproducible results (Note 1), in allcases of dispute give the test specimens of laminated rods a conditioning treatment for physical test as follows:5.1.1 Tensile, Flexural, and Compressive Strengths, and DensityPrior to test, condition the machined specimens in accordancewith Proce
16、dure B of Practice D6054. All specimens shall be tested at room temperature maintained at 23 6 5 C.NOTE 1Conditioning of specimens may be undertaken: The following are potential reasons to undertake conditioning of specimens: (a) for thepurpose of bringing the material into equilibrium with normal o
17、r average room conditions of 23 C and 50 % relative humidity; (b) simply to obtainreproducible results, irrespective of previous history of exposure; or (c) to subject the material to abnormal conditions of temperature or humidity in orderto predict its service behavior.The conditions given here to
18、obtain reproducible results maywill give physical values which could be somewhat higher or somewhat lower than valuesunder equilibrium at normal conditions, depending upon the particular material and test. To ensure substantial equilibrium under normal conditions ofhumidity and temperature, however,
19、 will require from 20 to 100 days or more depending upon thickness and type of material and its previous history.Consequently, conditioning for reproducibility must of necessity be used for general purchase specifications and product control tests.6. Dimensional Measurements6.1 Make dimensional meas
20、urements of rods in accordance with Test Methods D668.TENSILE STRENGTH7. Significance and Use7.1 This test method is designed to provide data for the control and specification of materials and for characterization purposesin research and development of new materials. Tensile properties mayIt is poss
21、ible that the tensile properties will vary with thesize of specimens and the speed of testing. Consequently, these factors along with others noted herein must be controlled whereprecise comparative results are desired.8. Apparatus8.1 Any testing machine may be used is acceptable for use provided it
22、is accurate to 1 % of the lowest breaking force to beapplied. Use jaws which tighten under load, such as wedge grip jaws, with the specimen properly aligned.9. Test Specimens9.1 Prepare the test specimen as shown in Fig. 1. The length, L, is as shown in Table 1. Machine a groove around the specimena
23、t the center of its length so that the diameter of the machined portion is 60 % of the original nominal diameter. This grooveconsists of a straight section 2 14 in. (57 mm) in length with a radius of 3 in. (76 mm) at each end joining it to the outside diameter.10. Procedure10.1 Adjust the crosshead
24、speed of the testing machine not to exceed 0.050 in. (1.27 mm)/min when running idle and test fivespecimens.11. Report11.1 Report the following information:11.1.1 The average diameter of the specimen, expressed to the nearest 0.001 in. (0.0254 mm), determined from at least twomeasurements 90 apart,1
25、1.1.2 The average diameter of the reduced section, expressed to the nearest 0.001 in. (0.025 mm), determined from at least twomeasurements 90 apart,11.1.3 Crosshead speed in inches per minute (or millimetres).11.1.4 The breaking load of each specimen in pounds-force (or newtons),11.1.5 The tensile s
26、trength of each specimen in pounds-force per square inch, (or pascals), and11.1.6 The room temperature in degrees Celsius.12. Precision and Bias12.1 PrecisionThis test method has been in use for many years, but no statement of precision has been available and noactivity is planned to develop such a
27、statement.12.2 BiasA statement of bias is not applicable in view of the lack of a standard reference material for this property.D349 132FLEXURAL STRENGTH13. Significance and Use13.1 Flexural strength data are useful for the control and specification of materials and to provide guidance in the design
28、 ofelectrical equipment. Flexural properties may have the potential to vary with the size of the specimens and the speed of testing.Consequently, these factors, together with others noted herein, must be controlled where precise comparative results are desired.14. Apparatus14.1 Any testing machine m
29、ay be used is acceptable for use provided it is accurate to 1 % of the lowest breaking force to beapplied.15. Test Specimens15.1 Prepare the test specimen with a diameter equal to that of the rod and a length eight times the diameter, plus 1 in. (25.4mm) for rods under 12 in. (12.7 mm) in diameter.
30、For rods over 12 in. and up to 2 in. (50.8 mm) in diameter, machine specimensto a diameter of 12 in. and cut to a length of 6 in. (152.4 mm).15.2 When the rod being tested is not circumferentially isotropic, prepare specimens for testing in both of the principaldirections, and identify them as to di
31、rectionality. This particularly includes rods machined from stripmolded or sheet stock.Metric Equivalentsin. mm2 50.8214 57.13 76.2312 88.9in. mm2 50.8214 57.13 76.2312 88.9FIG. 1 Diagram Showing Location of Rod Tension TestSpecimen in Testing MachineD349 13316. Procedure16.1 Test five specimens for
32、 each laminate orientation, each as a simple beam loaded at the center. The distance between thesupports shall be eight times the diameter of the rod. The supports shall have contact edges rounded to a radius of 18 in. (3.2 mm).Adjust the crosshead speed of the testing machine not to exceed an idle
33、speed of 0.050 in./min (1.27 mm/min) and apply the loadthrough a steel block having a semi-circular contact edge of the same radius as the rod, with edges rounded to a radius of 18 in.(3.2 mm).17. Calculation17.1 Calculate the maximum fiber stress, S, as follows:S 58 WL/pid 3 (1)where:W = breaking l
34、oad, lbf (N),L = distance between supports, in. (mm), andd = diameter, in (mm).18. Report18.1 Report the following information:18.1.1 The diameter of the specimen expressed to the nearest 0.001 in. (0.0254 mm), determined from at least twomeasurements 90 apart,18.1.2 Crosshead speed in inches per mi
35、nute (or millimetres),18.1.3 The breaking load of each specimen in pounds-force (or newtons),18.1.4 The maximum fiber stress S, in pounds-force per square inch (pascals), and18.1.5 The direction of loading relative to the direction of the laminate if the rods are ground from strip-molded stock, shee
36、tstock, and vulcanized fiber.TABLE 1 Dimensions of Rod SpecimensNominal Diameter,in. (mm)Length of Radial Sections2 RS, in. (mm)Total Calculated MinimumLength of Specimen,in. (mm)Standard Length, L, of Speci-men to be Used for 3 12 in.(88.9 mm) JawsA18 (3.2) 0.773 (19.63) 14.02 (35.61) 15 (381.0)316
37、 (4.8) 0.946 (24.03) 14.20 (36.06) 15 (381.0)14 (6.4) 1.091 (27.71) 14.34 (36.42) 15 (381.0)38 (9.5) 1.333 (33.86) 14.58 (37.03) 15 (381.0)12 (12.7) 1.563 (38.01) 14.79 (37.56) 15.75 (400.0)58 (15.9) 1.714 (43.56) 14.96 (37.99) 15.75 (400.0)34 (19.0) 1.813 (46.05) 15.12 (38.40) 15.75 (400.0)78 (22.1
38、) 2.019 (51.28) 15.27 (38.78) 15.75 (400.0)1 (25.4) 2.154 (54.71) 15.40 (39.11) 16.5 (414.0)114 (31.8) 2.398 (60.90) 15.65 (39.75) 16.5 (414.0)112 (38.0) 2.615 (66.42) 15.87 (40.31) 16.5 (414.0)134 (44.5) 2.812 (70.41) 16.06 (40.79) 16.5 (414.0)2 (50.8) 2.993 (76.02) 16.24 (41.25) 17 (432.0)TABLE 1
39、Dimensions of Rod SpecimensNominal Diameter,in. (mm)Length of Radial Sections2 RS, in. (mm)Total Calculated MinimumLength of Specimen,in. (mm)Standard Length, L, of Speci-men to be Used for 3 12 in.(88.9 mm) JawsA18 (3.2) 0.773 (19.63) 14.02 (35.61) 15 (381.0)316 (4.8) 0.946 (24.03) 14.20 (36.06) 15
40、 (381.0)14 (6.4) 1.091 (27.71) 14.34 (36.42) 15 (381.0)38 (9.5) 1.333 (33.86) 14.58 (37.03) 15 (381.0)12 (12.7) 1.563 (38.01) 14.79 (37.56) 15.75 (400.0)58 (15.9) 1.714 (43.56) 14.96 (37.99) 15.75 (400.0)34 (19.0) 1.813 (46.05) 15.12 (38.40) 15.75 (400.0)78 (22.1) 2.019 (51.28) 15.27 (38.78) 15.75 (
41、400.0)1 (25.4) 2.154 (54.71) 15.40 (39.11) 16.5 (414.0)114 (31.8) 2.398 (60.90) 15.65 (39.75) 16.5 (414.0)112 (38.0) 2.615 (66.42) 15.87 (40.31) 16.5 (414.0)134 (44.5) 2.812 (70.41) 16.06 (40.79) 16.5 (414.0)2 (50.8) 2.993 (76.02) 16.24 (41.25) 17 (432.0)AFor other jaws greater than 3 12 in. (88.9 m
42、m), the standard length shall be increased by twice the length of the jaw minus 7 in. (177.8 mm). The standard length permitsa slippage of approximately 14 to 12 in. (6.35 to 12.7 mm) in each jaw while maintaining maximum length of jaw grip.D349 13419. Precision and Bias19.1 PrecisionThis test metho
43、d has been in use for many years, but no statement of precision has been available and noactivity is planned to develop such a statement.19.2 BiasA statement of bias is not applicable in view of the lack of a standard reference material for this property.COMPRESSIVE STRENGTH (AXIAL)20. Significance
44、and Use20.1 Compression tests, properly interpreted, provide reasonably accurate information with regard to the compressive propertiesof rigid round rods when employed under conditions approximating those under which the tests are made. The compressivestrength values may have the potential to vary w
45、ith the size of the rigid round rod, and with temperature and atmosphericconditions. Compression tests may provide data potentially useful for research and development, engineering design, qualitycontrol, and acceptance or rejection under specifications.21. Apparatus21.1 Any testing machine may be u
46、sed is acceptable for use provided it is accurate to 1 % of the lowest breaking force to beapplied. One end of the specimen shall bear upon an accurately centered spherical bearing block, located, whenever practicable,at the top. The metal bearing plates shall be directly in contact with the ends of
47、 the test specimen.22. Test Specimens22.1 Unless otherwise specified in the test method or specification for that material, test the samples as received. For rods 18to 1 in. (3.2 to 25.4 mm) in diameter, prepare the test specimen with a diameter equal to the diameter of the rod, and lengthconforming
48、 to the following requirements:COLSPEC/colnum=“1“Diameter, in. (mm)Length, in.(mm)SlendernessRatio18 to 14 (3.2 to 6.4) incl 12 (12.7) 16 to 8Over 14 to 12 (6.4 to 12.7) incl 1 (25.4) 16 to 8Over 12 to 1 (12.7 to 25.4) incl 2 (50.8) 16 to 822.2 For rods over 1 in. (25.4 mm) in diameter, specimens ar
49、e standard 12 by 12 by 1-in. (12.7 by 12.7 by 25.4-mm) rightparallelepiped, cut from the rods so as to be representative of their cross sections both at the center and near the edges.22.3 Accurately cut or grind the ends of each specimen parallel to each other.23. Procedure23.1 Adjust the crosshead speed of the testing machine not to exceed an idle speed of 0.050 in./min (1.27 mm/min), and testfive specimens with the load applied perpendicular to the faces or ends of the specimen.23.2 Discard speci
