1、Designation: B 298 07Standard Specification forSilver-Coated Soft or Annealed Copper Wire1This standard is issued under the fixed designation B 298; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A numbe
2、r in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification covers silver-coated, soft or annealed,round copper wire, intended for use in electrical equipment, asfollows:1.1.1 Clas
3、s AWire whose silver coating is at least 1.25 %of the total weight of the coated wire.1.1.2 Class BWire whose silver coating is at least 2.50 %of the total weight of the coated wire.1.1.3 Class CWire whose silver coating is at least 4.00 %of the total weight of the coated wire.1.1.4 Class DWire whos
4、e silver coating is at least 6.10 %of the total weight of the coated wire.1.1.5 Class EWire whose silver coating is at least10.00 % of the total weight of the coated wire.1.2 Silver-coated wire having different minimum percent-ages of silver by weight may be obtained by mutual agreementbetween the m
5、anufacturer and the purchaser. For informationpurposes the thickness of coating in microinches provided bythe percentages listed above is shown in Table 1 (ExplanatoryNote 1).1.3 The SI values of resistance and density are to beregarded as standard. For all other properties values stated ininch-poun
6、d units are to be regarded as the standard. The valuesgiven in parentheses are provided for information purposesonly.1.4 The following precautionary caveat pertains only to thetest method section of this specification: This standard does notpurport to address all of the safety concerns, if any, asso
7、ciatedwith its use. It is the responsibility of the user of this standardto establish appropriate safety and health practices anddetermine the applicability of regulatory limitations prior touse. For specific precautionary statements see 8.4.1.2 andExplanatory Note 2.2. Referenced Documents2.1 The f
8、ollowing documents of the issue in effect at thetime of reference form a part of this specification to the extentreferenced herein:2.2 ASTM Standards:2B4 Discontinued 1981; Specification Tough-Pitch LakeCopper-Refinery Shapes3B5 Specification for High Conductivity Tough-Pitch Cop-per Refinery Shapes
9、B 193 Test Method for Resistivity of Electrical ConductorMaterialsB 258 Specification for Nominal Diameters and Cross-SectionalAreas ofAWG Sizes of Solid Round Wires Usedas Electrical ConductorsE50 Practices for Apparatus, Reagents, and Safety Consid-erations for Chemical Analysis of Metals, Ores, a
10、ndRelated Materials3. 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 5.3 and Table 1),3.1.3 Class of coating (Section 1 and Table 1),3.1.4 Type of copper, if special (see
11、 4.2),3.1.5 Place of inspection (see 9.1), and3.1.6 Packaging and Package Marking (Section 10).1This specification is under the jurisdiction of ASTM Committee B01 onElectrical Conductors and is the direct responsibility of Subcommittee B01.04 onConductors of Copper and Copper Alloys.Current edition
12、approved May 15, 2007. Published . Originally approved in1955. Last previous edition approved in 1999 as B 298 99e1.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to
13、the standards Document Summary page onthe ASTM website.3Withdrawn.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.1.7 In addition supplementary requirements shall applyonly when specified by the purchaser in the inquiry, contract,
14、orpurchase order for direct procurement by agencies of the U.S.Government (see S1, S2, and S3).4. Materials and Manufacture4.1 The material shall be silver-coated copper wire (Ex-planatory Note 2), of such quality and purity that the finishedproduct shall have the properties and characteristics pres
15、cribedin this specification.NOTE 1The following specifications define copper suitable for use:Specifications B4andB5.4.2 Copper of special qualities, forms, or types, as may beagreed upon between the manufacturer and the purchaser, andthat will conform to the requirements prescribed in thisspecifica
16、tion may also be used.5. General Requirements General Requirements5.1 Tensile PropertiesThe silver-coated wire shall con-form to the requirements for elongation prescribed in Table 1.No requirements for tensile strength are specified. For wirewhose nominal diameter is more than 0.001 in. (1 mil) gre
17、aterthan a size listed in Table 1, but less than that of the next largersize, the requirements of the next larger size shall apply.5.2 Resistivity The electrical resistivity of the coated wireat a temperature of 20C shall not exceed 875.20 ohmslb/mile2.5.3 Dimensions and Permissible VariationsThe wi
18、re sizesshall be expressed as the diameter of the wire in decimalfractions of an inch to the nearest 0.1 mil (0.0001 in.)(Explanatory Note 3). The coated wire shall not vary from thespecified diameter by more than the following amounts:Nominal Diameter, in.Permissible Variations inDiameter, plus and
19、 minusUnder 0.0100 0.0001 in.(0.1 mil)0.0100 or over 1 %5.4 Continuity of CoatingThe coating shall be continu-ous. The continuity of the coating shall be determined onrepresentative samples taken before stranding or insulating andshall be determined by the sodium polysulfide test, in accor-dance wit
20、h 8.4. Wire whose coating weight corresponds to athickness less than 40 in. (0.00004 in.) shall not be subject tothis test (Explanatory Note 4).5.5 Weight of CoatingThe weight of coating expressed inpercent of the total weight of the wire shall be not less thanTABLE 1 Tensile RequirementsDiameter,in
21、.Area at 20CElongationin 10 in.,min, %Thickness of Coating, in. (For Information Only)cmils in.2Class A, 1.25% SilverClass B, 2.50% SilverClass C, 4.00% SilverClass D, 6.10% SilverClass E, 10.00% Silver0.1285 16 510 0.01297 30 340 680 1 090 1 659 2 7200.1144 13 090 0.01028 30 303 605 970 1 477 2 422
22、0.1019 10 380 0.008155 25 270 539 864 1 316 2 1570.0907 8 230 0.00646 25 240 480 768 1 171 1 9410.0808 6 530 0.00513 25 214 428 684 1 043 1 7100.0720 5 180 0.00407 25 190 381 610 930 1 5240.0641 4 110 0.00323 25 170 339 542 828 1 3570.0571 3 260 0.00256 25 151 302 483 737 1 2090.0508 2 580 0.00203 2
23、5 134 269 430 656 1 0750.0453 2 050 0.00161 25 120 240 383 585 9590.0403 1 620 0.00128 25 107 213 341 520 8530.0359 1 290 0.00101 25 95 190 304 464 7600.0320 1 020 0.000804 25 85 169 270 413 6770.0285 812 0.000638 25 75 151 241 368 6030.0253 640 0.000503 25 67 134 214 327 5360.0226 511 0.000401 25 6
24、0 120 191 292 4780.0201 404 0.00317 20 53 106 170 260 4250.0179 320 0.000252 20 47 95 151 231 3790.0159 253 0.000199 20 42 84 135 205 3370.0142 202 0.000158 20 . 75 120 183 3010.0126 159 0.000125 20 . 67 107 163 2670.0113 128 0.000100 20 . 60 96 146 2390.0100 100 0.0000785 20 . 53 85 129 2120.0089 7
25、9.2 0.0000622 15 . 47 75 115 1880.0080 64.0 0.0000503 15 . 42 68 103 1690.0071 50.4 0.0000396 15 . . 60 92 1500.0063 39.7 0.0000312 15 . . 53 81 1330.0056 31.4 0.0000246 15 . . 47 72 1190.0050 25.0 0.0000196 15 . . 42 65 1060.0045 20.2 0.0000159 15 . . . 58 950.0040 16.0 0.0000126 15 . . . 52 850.00
26、35 12.2 0.00000962 15 . . . 45 740.0031 9.61 0.00000755 15 . . . 40 660.0028 7.84 0.00000616 10 . . . . 590.0025 6.25 0.00000491 10 . . . . 530.00220.00204.844.000.000003800.000003141010.4742 This value was corrected editorially to conform with Table X1.1.B2980721.25 % for Class A; 2.50 % for Class
27、B; 4.00 % for Class C;6.10 % for Class D; and 10.00 % for Class E. When coatingsother than these classes are required, the weight of the coatingshall be not less than that specified. For ease of comparison, thethickness of coating for these classes has been included inTable 1 (Explanatory Note 4).5.
28、6 JointsNecessary joints in the wire and rods prior tofinal plating and drawing shall be made in accordance with thebest commercial practice. Joints made after plating shall not beallowed to remain in the final product.5.7 FinishThe coating shall consist of a smooth continu-ous layer, firmly adheren
29、t to the surface of the copper. The wireshall be bright and free from all imperfections not consistentwith the best commercial practice.6. Conformance Criteria (Explanatory Note 5)6.1 Any lot of wire, the samples of which comply with theconformance criteria of this section, shall be considered ascom
30、plying with the requirements of Section 5. Individualproduction units that fail to meet one or more of the require-ments shall be rejected. Failure of a sample group from a lot tomeet one or more of the following criteria shall constitutecause for rejection of the lot. The conformance criteria for e
31、achof the prescribed properties given in Section 5 are as follows:6.1.1 ElongationThe lot shall be considered conformingif the elongation of each of the selected specimens is not lessthan the elongation value in Table 1.6.2 Resistivity The electrical resistivity of each of the fourspecimens shall co
32、nform to the requirements of 5.2. Failure tomeet these requirements shall constitute failure to meet theresistivity conformance criterion.6.3 DimensionsThe dimensions of the first sample (Table2) shall conform to the requirements of 5.3. If there are nofailures, the lot conforms to this requirement.
33、 If there arefailures, but the number of these do not exceed the allowabledefect number, c2(Table 2), for the respective number of unitsin the sample, a second sample equal to n2shall be taken andthe total defects of the n plus n2units shall not exceed theallowable defect number, c2. Failure to meet
34、 this requirementshall constitute failure to meet the dimensional conformancecriterion.6.4 Continuity of CoatingThe continuity of the coating ofeach of the eight specimens shall conform to the requirementsof 5.4. Failure of more than two specimens shall constitutefailure to meet the continuity crite
35、rion. If not more than twospecimens fail to meet the continuity criteria, eight additionalspecimens from the lot shall be tested, all of which shallconform to the continuity criteria. However, any individualproduction unit, the specimen from which failed to meet thecontinuity criteria, shall be reje
36、cted.6.5 Weight of CoatingThe weight of coating of each of thefour specimens shall conform to the requirements of 5.5.Failure of more than one specimen shall constitute failure tomeet the weight criteria. If only one specimen fails to meet theweight criteria, four additional specimens from the lot s
37、hall betested, all of which shall conform to the weight criterion.However, any individual production unit, the specimen fromwhich failed the weight criteria, shall be rejected.6.6 PackagingConformance to the packaging require-ments specified by the purchaser shall be determined inaccordance with Tab
38、le 3. The number of units in the sampleshowing nonconformance to the requirements shall not exceedthe allowable defect number, c,inTable 3. Failure to meet thisrequirement shall constitute failure to meet the packagingconformance criterion.7. Density7.1 For the purpose of calculating weights, cross-
39、sections,etc., the density of the copper shall be taken as 8.89 g/cm3(0.32117 lb/in.3) at 20C (Explanatory Note 6). The density ofsilver shall be taken as 10.5 g/cm3(0.1 mil) (0.37933 lb/in.3).8. Test Methods8.1 Tensile Strength and Elongation:8.1.1 No test for tensile strength shall be required.8.1
40、.2 The elongation of wire whose nominal diameter islarger than 0.0808 in. (2.052 mm) in diameter shall bedetermined as the permanent increase in length, expressed inpercent of the original length, due to the breaking of the wirein tension, measured between gage marks placed originally 10in. (254 mm)
41、 apart upon the test specimen (Explanatory Note7). The elongation of wire whose nominal diameter is 0.0808in. and under may be determined as described above or bymeasurements made between the jaws of the testing machine.When the latter method is used, the zero length shall be thedistance between the
42、 jaws at the start of the tension test and beas near 10 in. as practicable, and the final length shall be thedistance between the jaws at the time of rupture. The fractureshall be between gage marks, in the case of specimens soTABLE 2 Sampling for Dimensional Measurements and Surface FinishNumber of
43、 Unitsin LotFirst Sample Second SampleAllowableNumber ofDefects inBoth Samplec2Number ofUnits inSample,n1AllowableNumber ofDefects inFirst Sample,c1Number ofUnits inSample,n2n1+ n21 to 14, incl All 0 . . .15 to 50, incl 14 0 . . .51 to 100, incl 19 0 23 42 1101 to 200, incl 24 0 46 70 2201 to 400, i
44、ncl 29 0 76 105 3401 to 800, incl 33 0 112 145 4Over 800 34 0 116 150 4B298073marked, or between the jaws of the testing machine and notcloser than 1 in. (25.4 mm) to either gage mark or either jaw.8.2 Resistivity The electrical resistivity of the materialshall be determined in accordance with Test
45、Method B 193(Explanatory Note 8). The purchaser may accept certificationthat the wire was drawn from rod stock meeting the Interna-tional Standard for Annealed Copper in lieu of resistivity testson the finished wire.8.3 Dimensional MeasurementsDimensional measure-ments shall be made with a micromete
46、r caliper equipped witha vernier graduated in 0.0001 in. Each coil shall be gaged atthree places, one near each end and one near the middle. Fromeach spool approximately 12 ft (3.7 m) shall be unreeled andthe wire gaged in six places between the second and twelfthfoot from the end. The average of th
47、e measurements obtainedshall meet the requirements of 5.3.8.4 Continuity of Coating:8.4.1 Specimens:8.4.1.1 Length of SpecimensTest specimens shall eachhave a length of about 6 in. (152 mm). They shall be tagged ormarked to correspond with the coil, spool, or reel from whichthey were cut.8.4.1.2 Tre
48、atment of SpecimensThoroughly clean thespecimens by immersion in a suitable organic solvent for atleast 3 min; then remove and wipe dry with a clean, soft cloth(Warning: See Explanatory Note 2). Keep the specimens thuscleaned wrapped in a clean, dry cloth until tested. Do nothandle that part of the
49、specimen to be immersed in thetestsolution. Take care to avoid abrasion by the cut ends.8.4.2 Special Solutions:8.4.2.1 Sodium Polysulfide Solution (sp gr 1.142)Make aconcentrated solution by dissolving sodium sulfide crystals(cp) in distilled water until the solution is saturated at about21C, and adding sufficient flowers of sulfur (in excess of 250g/L of solution) to provide complete saturation, as shown bythe presence in the solution of an excess of sulfur after thesolution has been allowed to stand for at least 24 h. Make thetest solution b
