1、Designation: B246 15Standard Specification forTinned Hard-Drawn and Medium-Hard-Drawn Copper Wirefor Electrical Purposes1This standard is issued under the fixed designation B246; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、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. Scope1.1 This specification cover
3、s tinned hard-drawn andmedium-hard-drawn round copper wire for electrical purposes.1.2 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.
4、2.1 ExceptionFor density, resistivity and temperature,the values stated in SI units are to be regarded as standard.1.3 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
5、safety and health practices and determine the applica-bility of regulatory limitations prior to use. For hazardstatement, see Sections 10 and 13.2. Referenced Documents2.1 The following documents of the issue in effect on thedate of material purchase form a part of this specification to theextent re
6、ferenced herein:2.2 ASTM Standards:2B5 Specification for High Conductivity Tough-Pitch CopperRefinery ShapesB49 Specification for Copper Rod Drawing Stock for Elec-trical PurposesB170 Specification for Oxygen-Free Electrolytic CopperRefinery ShapesB193 Test Method for Resistivity of Electrical Condu
7、ctorMaterials2.3 National Bureau of Standards:3NBS Handbook 100Copper Wire Tables3. Ordering Information3.1 Orders for material under this specification shall includethe following information:3.1.1 Quantity of each size,3.1.2 Wire size, diameter in inches (see 5.1 and Table 1),3.1.3 Type of copper,
8、if special (see 4.2),3.1.4 Temper (see 7.1 and Table 1),3.1.5 Package size (see 18.1),3.1.6 Special package marking, if required, and3.1.7 Place of inspection (Section 16).4. Materials4.1 The tinned wire shall be made by coating hard-drawnand medium-hard-drawn copper wire with commercially puretin (
9、see Note 1). For purposes of this specification, the tin shallbe considered commercially pure if the total of other elements,exclusive of copper, does not exceed 1 %. Notwithstanding theprevious sentence, chemical analysis of the tin coating or of thetin used for coating shall not be required under
10、this specifica-tion. Adequacy of the tin coating is ensured by the continuityof coating and adherence of coating requirements (Sections 9and 13, respectively).4.2 The copper shall be copper of such quality and puritythat the finished product shall have the properties and charac-teristics prescribed
11、in this specification.NOTE 1Specification B49 defines copper suitable for use.4.3 Copper bars of special qualities, forms, or types, as maybe agreed upon between the manufacturer and the purchaser,and which will conform to the requirements prescribed in thisspecification may also be used.5. Dimensio
12、ns, Mass, and Permissible Variations5.1 The wire sizes shall be expressed as the diameter of thecoated wire in decimal fractions of an inch to the nearest0.0001 in. (0.001 mm) (Explanatory Note 5).1This specification is under the jurisdiction of ASTM Committee B01 onElectrical Conductors and is the
13、direct responsibility of Subcommittee B01.04 onConductors of Copper and Copper Alloys.Current edition approved April 1, 2015. Published April 2015. Originallyapproved in 1951. Last previous edition approved in 2010 as B246 05 (2010).DOI: 10.1520/B0246-15.2For referenced ASTM standards, visit the AST
14、M website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from National Technical Information Service (NTIS), 5301 ShawneeRd., Alexandria, VA 22312, http
15、:/www.ntis.gov.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15.2 The coated wire shall not vary from the specifieddiameter by more than +3 % or 1 %.5.3 Ten percent, but not less than five coils or spools (or all,if the lot is less t
16、han five) from any lot of wire shall be takennear each end and one near the middle. If any of these selectedcoils or spools fails to conform to the requirements prescribedin 5.2, all coils or spools shall be gaged in the mannerspecified.6. Workmanship, Finish, and Appearance6.1 The tin coating shall
17、 consist of a smooth continuouslayer, firmly adhering to the surface of the copper.6.2 The wire shall be free from all imperfections notconsistent with the best commercial practice.7. Tensile Properties7.1 The tinned wire shall conform to the requirements as totensile properties prescribed in Table
18、1 (Explanatory Note 1).7.2 For wire the nominal diameter of which is more than0.001 in. (0.025 mm) greater than a size listed in Table 1, butwhich is less than that of the next larger size, the requirementsof the next larger size shall apply.7.3 Tension tests shall be made on representative samples.
19、Determine the elongation of the wire as the permanent increasein length due to the breaking of the wire in tension, measuredbetween gage marks placed originally 10 in. (250 mm) apartupon the test specimen (Explanatory Note 2).7.4 If any part of the fracture takes place outside the gagemarks or in th
20、e jaws of the testing machine, or if an examina-tion of the specimen indicates a flaw, the value obtained maynot be representative of the material. In such cases the test maybe discarded and a new test made.7.5 RetestsIf upon testing a specimen from any coil orspool of wire, the results do not confo
21、rm to the requirementsprescribed in Table 1, two additional specimens shall be tested,and the average of the three tests shall determine the accep-tance or rejection of the coil or spool.8. Resistivity8.1 Electrical resistivity shall be determined on representa-tive specimens by resistance measureme
22、nts made in accor-dance with Test Method B193. At a temperature of 20C theresistivity of coated wire shall not exceed the values prescribedin Table 2 (Explanatory Note 3).9. Continuity of Coating9.1 The continuity of coating on the wire shall be deter-mined on representative samples taken before str
23、anding orinsulating (Explanatory Note 4).TABLE 1 Tensile RequirementsTinned Medium-Hard-Drawn WireTinned Hard-Drawn Wire Tensile Strength, min.Diameter Area at 20C Tensile Strength, min.Elongationin 10 in.(250mm),%minpsi MpaElongationin 10 in.(250mm),%minin. mm cmil in.2mm2psi Mpa min. max. min. max
24、.0.2043 5.189 41738 0.03278 21.15 54100 370.6 1.7 42400 55300 290.4 378.8 1.90.1819 4.620 33088 0.02599 16.77 55100 377.4 1.6 43300 55700 296.6 381.5 1.70.1620 4.115 26244 0.02061 13.30 55900 382.9 1.4 44100 56000 302.1 383.6 1.50.1443 3.665 20822 0.01635 10.55 56700 388.4 1.3 44900 56300 307.6 385.
25、6 1.40.1285 3.264 16512 0.01297 8.367 57300 392.5 1.3 45500 56700 311.7 388.4 1.30.1144 2.906 13087 0.01028 6.632 57900 396.6 1.2 46000 57000 315.1 390.4 1.30.1019 2.588 10384 0.008155 5.262 58400 400.0 1.2 46500 57300 318.5 392.5 1.20.0907 2.304 8226 0.006461 4.1684 58900 403.5 1.1 46900 57700 321.
26、3 395.2 1.20.0808 2.052 6529 0.005128 3.308 59100 404.8 1.1 47200 58000 323.3 397.3 1.10.0720 1.829 5184 0.004072 2.627 59300 406.2 1.1 47300 58300 324.0 399.3 1.10.0641 1.628 4109 0.003227 2.082 59600 408.2 1.0 47600 58700 326.1 402.1 1.00.0571 1.450 3260 0.002561 1.652 59800 409.6 1.0 47800 59000
27、327.4 404.1 1.00.0508 1.290 2581 0.002027 1.308 59900 410.3 1.0 47900 59300 328.1 406.2 1.0TABLE 2 Electrical Resistivity RequirementsResistivity at 20CNominal Diameter lb/mile2g/m2in. mm Hard Medium-Hard Hard Medium-Hard0.2043 to 0.103, incl 5.2 to 2.6, incl 943.92 938.85 0.1653 0.1644Under 0.103 t
28、o 0.0508, incl Under 2.6 to 1.3, incl 910.15 946.06 0.1594 0.1657B246 1529.2 The continuity of the tin coating shall be determined bythe sodium polysulfide test, which shall be applied as specifiedin Sections 1012.10. Specimens for Coating Tests10.1 Length of SpecimensTest specimens shall each havea
29、 length of about 6 in. They shall be tagged or marked tocorrespond with the coil, spool, or reel from which they werecut.10.2 Treatment of SpecimensThe specimens shall be thor-oughly cleaned by immersion in a suitable solvent for theappropriate time required to remove oil or grease from surface;then
30、 removed and wiped dry with a clean soft cloth(Cautionsee Explanatory Note 6). The specimens thuscleaned shall be kept wrapped in a clean, dry cloth until tested.That part of the specimen to be immersed in the test solutionshall not be handled. Care shall be taken to avoid abrasion bythe cut ends.11
31、. Special Solutions Required11.1 Hydrochloric Acid Solution (sp gr 1.088)Commercial HCl (sp gr 1.12) shall be diluted with distilledwater to a specific gravity of 1.088 measured at 15.6C. Aportion of HCl solution having a volume of 180 mL shall beconsidered to be exhausted when the number of test sp
32、ecimensprescribed in Table 3 of a size as indicated in Section 12 havebeen immersed in it for two cycles.11.2 Sodium Polysulfide Solution (sp gr 1.142)A concen-trated solution shall be made by dissolving sodium sulfide cpcrystals in distilled water until the solution is saturated at about21C, and ad
33、ding sufficient flowers of sulfur (in excess of 250g/L of solution) to provide complete saturation as evidenced bythe presence in the solution of an excess of sulfur after thesolution has been allowed to stand for at least 24 h. The testsolution shall be made by diluting a portion of the concentrate
34、dsolution with distilled water to a specific gravity of 1.142 at15.6C. The sodium polysulfide test solution shall have suffi-cient strength to blacken thoroughly a piece of clean untinnedcopper wire in 5 s.Aportion of the test solution used for testingsamples shall not be considered to be exhausted
35、until it fails toblacken a piece of clean copper as described here (ExplanatoryNote 6).12. Procedure for Coating Continuity Test12.1 Immersion of SpecimensImmerse a length of at least412 in. from each of the clean specimens, in accordance withthe following cycles, in test solutions maintained at a t
36、empera-ture between 15.6 and 21C:12.1.1 Immerse the specimen for 1 min in the HCl solutiondescribed in 11.1, wash, and wipe dry.12.1.2 Immerse the specimen for 30 s in the sodiumpolysulfide solution described in 11.2, wash, and wipe dry.12.1.3 Immerse the specimen for 1 min in HCl solutiondescribed
37、in 11.1, wash, and wipe dry.12.1.4 Immerse the specimen for 30 s in the sodiumpolysulfide solution described in 11.2, wash, and wipe dry.12.2 Washing SpecimensAfter each immersion, immedi-ately wash thoroughly the specimens in clean water and wipedry with a clean, soft cloth.12.3 Examination of Spec
38、imensAfter the operations de-scribed in 12.1 and 12.2, examine the specimens to ascertain ifcopper exposed through openings in the tin coating has beenblackened by action of the sodium polysulfide. The specimensshall be considered to have failed if by such blackeningexposed copper is revealed. Pay n
39、o attention to blackeningwithin 0.5 in. of the cut end.13. Mechanical Test for Adhesion of Coating13.1 Length of SpecimensTest specimens shall be ap-proximately 12 in. in length and shall be tagged or marked tocorrespond with the coil, spool, or reel from which they are cut.13.2 Preparation of Speci
40、menThoroughly clean thespecimens, if required, by immersion in a suitable solvent forthe appropriate time required to remove oil and grease fromsurface, then remove and dry (CautionExplanatory Note 6).Store the specimens thus cleaned wrapped in a clean, dry clothuntil tested. Do not handle that part
41、 of the specimens to beimmersed in the test solution. Use care to avoid abrasion of thesurface to be subjected to test.13.3 Wrapping ProcedureSlowly wrap the test specimenin a suitable manner in an open helix around a polishedmandrel having rounded ends and a diameter equal to fourtimes the diameter
42、 of the specimens. Use care not to stretch thespecimen during the wrapping operation. Make the spacing ofthe consecutive turns approximately equal to the diameter ofthe wire. Do not use more than three turns for the test.13.4 Immersion TestRemove the helically wrapped por-tion of the test specimen f
43、rom the mandrel and completelyimmerse in the sodium polysulfide solution (see 11.2) for 30 sat the temperature in accordance with 12.1. On removal fromthe sodium polysulfide solution, rinse the specimen immedi-ately in clean water and remove the excess by shaking.13.5 Examination of SpecimenExamine
44、visually the outerperipheral surface of the helically wrapped portion of thespecimen. Any cracking or parting of the coating in this areaTABLE 3 Limiting Number of Test Specimens for Coating TestsNominal DiameterMaximum Number ofSpecimens to Be Testedfor Two Cycles in 180 mLof Acid Solutionin. mm0.2
45、043 to 0.141, incl 5.2 to 3.6, incl 2Under 0.141 to 0.0851, incl Under 3.6 to 2.2, incl 4Under 0.0851 to 0.0508, incl Under 2.2 to 1.3, incl 6B246 153shown by blackening of the copper shall be cause for rejection.A grayish appearance of the coating after immersion shall notconstitute failure.13.6 Re
46、testIn the event of failure, two additional speci-mens shall be tested. If either of these specimen fails, the coil,reel, or spool shall be rejected.14. Joints14.1 Joints shall not be made in the wire after it has beendrawn to size or coated. Joints in the wire or rods prior to finaldrawing shall be
47、 made in accordance with the best commercialpractice (Explanatory Note 8).15. Density15.1 For the purpose of calculating mass per unit length,cross sections, etc., the density of the copper shall be taken as8.89 g/cm3or 0.32117 lb/in.3at 20C (Explanatory Note 9).16. Inspection16.1 All tests and insp
48、ection shall be made at the place ofmanufacture unless otherwise especially agreed upon betweenthe manufacturer and the purchaser at the time of purchase. Themanufacturer shall afford the inspector representing the pur-chaser all reasonable facilities to satisfy him that the materialis being furnish
49、ed in accordance with this specification.17. Rejection17.1 Wire that shows exposed copper by blackening aftertesting in the sodium polysulfide solution in accordance withSections 11 and 12, or that fails to conform to the otherrequirements of this specification, shall be rejected.18. Packaging and Package Marking18.1 Package sizes shall be agreed upon between the manu-facturer and the purchaser in the placing of individual orders(Explanatory Note 10).18.2 The coated wire shall be protected against damage inordinary handling and shipping.19. Keywords
