1、Designation: D668 99 (Reapproved 2004) D668 12 An American National StandardStandard Test Methods ofMeasuring Dimensions of Rigid Rods and Tubes Used forElectrical Insulation1This standard is issued under the fixed designation D668; the number immediately following the designation indicates the year
2、 oforiginal adoption or, in the case of revision, 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 Scope*1.1 These test methods cover the measurement of the d
3、imensions of all rigid rods and tubes used as electrical insulation, thelimitations imposed being those of the size range of the more common forms of measuring instruments used.1.2 Where the number of tests to be made or the specifications covering the rod or tube justify its use, it is acceptable t
4、o usean accurately calibrated “go-and-no-go” ring gage of suitable size may be used.size.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 practice
5、s and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D374 Test Methods for Thickness of Solid Electrical InsulationD1711 Terminology Relating to Electrical Insulation3. Terminology3.1 Definitions For definitions of terms used in these tes
6、t methods refer to Terminology D1711.4. Significance and Use4.1 These test methods are used to measure the dimensions of the rod or tube to determine conformance with specifications onfull lengths or cut lengths. The measurements can also be used for manufacturing control, determination of uniformit
7、y, dimensionalstability, and physical and electrical properties of the rods and tubes.5. Conditioning5.1 Condition specimens prior to testing for at least 48 h at 23 6 1 C and 50 6 2 % relative humidity. Perform tests in aircontrolled at that temperature and humidity.6. Method of Measurement6.1 Make
8、 all diameter and wall thickness measurements for specimens with dimensions 300 mm (12 in.) and under inaccordance with the procedure described in Test Methods D374 as applicable. Close the micrometer or vernier caliper slowly onthe specimen until contact is made without appreciable distortion of th
9、e specimen. The criterion of contact is the initialdevelopment of frictional resistance to movement of the specimen between the micrometer or caliper surfaces. Use a steel tape orsteel scale for measurement of length and diameter greater than 300 mm (12 in.).7. Length of Rods or Tubes 300 mm (12 in.
10、) and Under in Length7.1 ApparatusA machinists micrometer or vernier caliper of suitable size reading to 0.02 mm or 0.001 in.7.2 Test SpecimensSpecimens shall consist of rods or tubes 300 mm (12 in.) or shorter.7.3 ProcedureMeasure the length of the specimen to the nearest 0.02 mm or 0.001 in. Size
11、permitting, make fourmeasurements at points 90 apart around the circumference of the specimen.7.4 ReportReport the average of the measurements taken as the length of the rod or tube.8. Length of Rod or Tubes Over 300 mm (12 in.) in Length8.1 ApparatusSteel tape or steel scale of suitable length grad
12、uated in 0.5 mm or 164 in.8.2 Test SpecimensSpecimens shall consist of rods or tubes over 300 mm (12 in.) in length, including full lengths.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2
13、959. United States18.3 ProcedureMeasure the length of the specimen to the nearest 0.5 mm or 164 in. Size permitting, make four measurementsat points 90 apart around the circumference of the specimen.8.4 ReportReport the average of the measurements as the length of the rod or tube.9. Diameter of Rods
14、 or Outside Diameter of Tubes 300 mm (12 in.) and Under in Outside Diameter9.1 ApparatusA machinists micrometer or vernier caliper reading to 0.02 mm or 0.001 in.9.2 Test SpecimensSpecimens shall consist of tubes 300 mm (12 in.) and under in outside diameter or rods of any diameter.9.3 ProcedureMeas
15、ure the outside diameter of the specimen to the nearest 0.02 mm or 0.001 in. Make four measurements atpoints 45 apart around the circumference at each end and at the middle of the specimen.9.4 ReportReport the average of the twelve measurements as the outside diameter of the tube or the diameter of
16、the rod.9.4.1 In the case of tubes, report the variation in outside diameter as the difference between the maximum and minimumindividual outside diameter readings, together with all measurements made.NOTE 1Rods having a diameter greater than 300 mm are generally commercially available and no standar
17、d test procedures have been developed formeasuring dimensions of such rods.10. Outside Diameter of Tubes Over 300 mm (12 in.) in Outside Diameter10.1 ApparatusA flat steel tape graduated in steps of 0.5 mm or 164 in.10.2 Test SpecimenSpecimens shall consist of tubes over 300 mm (12 in.) in outside d
18、iameter.10.3 ProcedurePlace the steel tape tightly around the outside of the tube at a right angle to the long axis, and measure thecircumference to the nearest 0.5 mm or 164 in. Calculate the outside diameter by the following equation:D 5tape reading/pi!22t (1)where:D = average outside diameter of
19、tube, mm or in., andt = thickness of tape, mm or in.Make at least three measurements at three different locations on the tube.10.4 ReportReport the average of all measurements as the outside diameter of the tube.11. Inside Diameter of Tubes 300 mm (12 in.) and Under in Inside Diameter11.1 ApparatusA
20、 machinists The preferred option is to use a machinists inside micrometer or a vernier caliper of suitablesize reading to 0.02 mm or 0.001 in. preferably shall be used, although However, the use of a combination of a telescoping gageand a standard machinists outside micrometer may be usedis also acc
21、eptable (see 1.2).11.2 Test SpecimenSpecimen shall consist of tubes whose inside diameter is not over 300 mm (12 in.) nor under 3 mm (18in.).11.3 ProcedureMeasure the inside diameter of the specimen to the nearest 0.02 mm or 0.001 in. Make four measurements atpoints 45 apart around the circumference
22、 at each end of the specimen.11.4 ReportReport the average of the measurements taken as the inside diameter of the tube.12. Inside Diameter of Tubes Over 300 mm (12 in.) in Inside Diameter12.1 ProcedureDetermine the average inside diameter by subtracting twice the average wall thickness from the ave
23、rageoutside diameter. Determine the average wall thickness from an average of at least six measurements in accordance with Section13.13. Wall Thickness of Tubes13.1 ApparatusA ball foot micrometer or suitable vernier caliper reading to 0.02 mm or 0.001 in. shall be used for themeasurement of tubes 8
24、 mm (516 in.) and over in inside diameter. A dial micrometer reading to 0.02 mm or 0.001 in. shall be usedfor the measurement of tubes under 8 mm (516 in.) in inside diameter.13.2 Test SpecimensSpecimens shall consist of tubes of any length or diameter.1 These test methods are under the jurisdiction
25、 of ASTM Committee D09 on Electrical and Electronic Insulating Materials and are the direct responsibility of SubcommitteeD09.07 on Flexible and Rigid Insulating Materials.Current edition approved Nov. 1, 2004Nov. 1, 2012. Published November 1999November 2012. Originally approved in 1942. Last previ
26、ous edition approved in 19892004as D668 89.D668 99(2004). DOI: 10.1520/D0668-99R04.10.1520/D0668-12.2 For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards
27、Document Summary page on the ASTM website.D668 12213.3 ProcedureMeasure the wall thickness to the nearest 0.02 mm or 0.001 in. For tubes 8 mm (516 in.) and over in insidediameter, take four measurements at points 90 apart around the circumference at each end of the specimen. For tubes under 8 mm(516
28、 in.) in inside diameter, measure the wall thickness by placing the specimen over a mandrel of slightly smaller diameter whichis fixed in position at right angles relative to the spindle of the dial micrometer. Note a zero setting with the spindle against thepin. Then place the specimen over the pin
29、 and take readings at various points around the circumference of the specimen. Take atleast four readings.13.4 ReportReport the average of the measurements taken as the wall thickness of the tube.14. Variation in Wall Thickness of Tubes14.1 Apparatussee 13.1.14.2 Test SpecimensSpecimens shall consis
30、t of tubes of any length or diameter.14.3 ProcedureMeasure the wall thickness to the nearest 0.02 mm or 0.001 in. For tubes 8 mm (516 in.) and over in insidediameter, make a series of measurements around each end of the specimen. For tubes under 8 mm (516 in.) in inside diameter,measure the variatio
31、n in wall thickness by rotating the specimen around the mandrel and following the general procedure inaccordance with 13.3 for tubes of this size.14.4 ReportReport the difference between the maximum and minimum values as the variation in wall thickness. Also, reportall measurements taken.15. Warp15.
32、1 ApparatusA horizontal flat surface and a rigid bar with plane surface firmly fixed at right angles to the flat surface, bothbeing at least as long as the specimen. The height of the bar shall exceed half the diameter of the tube. Feeler gages of suitablethicknesses will also be required.15.2 Test
33、SpecimensSpecimens shall consist of rods or tubes of any length or diameter.15.3 ProcedurePlace the specimen in the fixture. With the aid of feeler gages, measure the maximum distance between therod or tube and the plane surface, rotating the specimen as necessary to locate the maximum. Measure to t
34、he nearest 0.02 mm or0.001 in.15.4 ReportReport warp or lack of straightness as the maximum distance measured in accordance with 15.3.15.5 CalculationCalculate the percentage warp based on a 1-m or 36-in. length as follows:Wm 51D/L 2!3100 or W36536D/L 2!3100 (2)where:Wm = percentage warp calculated
35、to a 1-m length,D = maximum deviation of the rod or tube from the straight edge, m or in.,L = actual length of the rod or tube as determined in accordance with the procedure described in Section 7 or 8, m or in., andW36 = percentage warp calculated in a 36-in. length.When it is desired to compare th
36、e actual deviation for any length with the permissible deviation for that length, use one of thefollowing equations may be used: equations:Dxm/Dm 5Lxm 2/1! 2 or Dx/D365Lx 2/36! 2 (3)where:Dxm = permissible deviation from the straight edge for the given length, m,Dm = permissible deviation for a 1-m
37、length,Lxm = given length, m,Dx = permissible deviation from the straight edge for the given length, in.,D36 = permissible deviation for a 36-in. length, andLx = given length, in.NOTE 2These requirements do not apply to cut pieces but only to rod or tube lengths as manufactured, unless otherwise agr
38、eed upon between themanufacturer and the purchaser.16. Precision and Bias16.1 These tests have been in use for many years, but no information has been presented to ASTM upon which to base astatement of precision. No activity has been planned to develop such information.16.2 These test methods have n
39、o bias because the values for these measurements are determined solely in terms of these testmethods themselves.D668 12317. Keywords17.1 dimensions; rigid rods; rigid tubes; wall thickness; warpSUMMARY OF CHANGESCommittee D09 has identified the location of selected changes to this specification sinc
40、e the last issue,D668 99R04, that may impact the use of this specification. (Approved November 1, 2012.)(1) Non-mandatory terms have been eliminated.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users
41、 of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every f
42、ive years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical
43、 committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken,
44、PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).D668 124
