1、Designation: B520 93 (Reapproved 2007) B520 12Standard Specification forTin-Coated, Copper-Clad Steel Wire for ElectronicApplication1This standard is issued under the fixed designation B520; the number immediately following the designation indicates the year oforiginal adoption or, in the case of re
2、vision, 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.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This specificatio
3、n covers tin-coated copper-clad steel wire for electronic application.1.2 Four classes of tin-coated copper-clad steel wire are covered as follows:1.2.1 Class T30HSNominal 30 % conductivity, hard-drawn,1.2.2 Class T30ANominal 30 % conductivity, annealed,1.2.3 Class T40HSNominal 40 % conductivity, ha
4、rd-drawn, and1.2.4 Class T40ANominal 40 % conductivity, annealed.1.3 The values stated in inch-pound units are to be regarded as the standard. The metric equivalents of inch-pound units maybe approximate. The values given in parentheses are for information only.standard. The values given in parenthe
5、ses aremathematical conversions to SI units that are provided for information only and are not considered standard.1.3.1 ExceptionThe SI values for resistivity and volume are to be regarded as standard.1.4 The following safety hazards caveat pertains only to the test method portion, Section 6, of th
6、is specification:This standarddoes not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of thisstandard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior touse.(Warn
7、ingConsideration should be given to toxicity and flammability when selecting solvent cleaners.)2. Referenced Documents2.1 The following documents of the issue in effect on date of material purchase form a part of this specification to the extentreferenced herein:2.2 ASTM Standards:2B193 Test Method
8、for Resistivity of Electrical Conductor MaterialsB258 Specification for Nominal Diameters and Cross-Sectional Areas of AWG Sizes of Solid Round Wires Used as ElectricalConductorsB452 Specification for Copper-Clad Steel Wire for Electronic Application2.3 National Institute of Standards and Technology
9、:3NBS Handbook 100 Copper Wire Tables3. Ordering Information3.1 Orders for material under this specification shall include the following information:3.1.1 Quantity of each size.3.1.2 Wire size (see 5.3 and Table 1),3.1.3 Class of wire (see 1.2),3.1.4 Package size and shipping (see 7.1.7 and Section
10、9), packaging inspection if required (see 9.3.3),1 This specification is under the jurisdiction of ASTM Committee B01 on Electrical Conductors and is the direct responsibility of Subcommittee B01.06 on CompositeConductors.Current edition approved Oct. 1, 2007Oct. 15, 2012. Published October 2007Nove
11、mber 2012. Originally approved in 1970. Last previous edition approved in 20022007as B520 70 (2002)B520 93 (2007).1 DOI: 10.1520/B0520-93R07.10.1520/B0520-12.2 For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at serviceastm.org. For Annual Book of
12、 ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 Available from National Institute of Standards and Technology (NIST), 100 Bureau Dr., Stop 1070, Gaithersburg, MD 20899-1070, http:/www.nist.gov.This document is not an ASTM standard and is intended
13、 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 appropriate. In all cases only the current v
14、ersionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.5 Special package marking, if required, and3.1.6 Place of inspection (see 9.1).4. Material4.1 The
15、 basis material shall consist of copper-clad steel wire conforming to the product description, quality and specificationrequirements of Specification B452.4.2 The tin-coated wire shall consist of the basis wire coated with tin. The tin used for coating shall be commercially pure (Note1). For purpose
16、s of this specification, the tin shall be considered“ commercially pure” if the total of other elements, exclusive ofcopper, does not exceed 1 %. Notwithstanding the previous sentence, chemical analysis of the tin coating or of the tin used forcoating shall not be required under this specification.
17、Adequacy of the tin coating is assured by the continuity of coating andadherence of coating requirements (see 5.4 and 5.5). The quality of the tin-coated wire shall be such that the finished product meetsthe properties and requirements in this specification.NOTE 1It is necessary that the coating of
18、the tin on the wire be continuous. The test in the sodium polysulfide is for the purpose of determiningwhether or not the wire carries a continuous envelope of pure tin. The thickness of the tin coating is necessarily varied. Under the same conditions oftinning, the coating on all sizes of wire, exc
19、epting on fine wire, is approximately the same. The coating on fine wire is in general relatively heavier thanthat on coarse wire. It is not, therefore, correct to apply a larger number of cycles in the test on coarse wire than is applied to fine wire. It is probablethat one cycle of the dip test wo
20、uld be sufficient to discover defects in tinned wire, but in order to make certain that no partially covered spots may escapeattention, provision has been made for two cycles. It has been found that the tin coating on copper wire consists of two parts, an envelope of pure tinon the outside, with an
21、intermediate layer of copper-tin alloy. This tin alloy, as well as the amount of tin present, has an effect on the resistivity of thewire. Since the relative amount of tin coating and alloy is greater on the small wire than it is on the coarser wire, the resistivity of the wire increasesas the size
22、decreases. This also accounts for the decrease in elongation due to tinning soft wire.5. General Requirements5.1 Tensile strength and elongation of the tin-coated wire shall conform to the requirements of Specification B452 for theapplicable size and class of copper-clad steel wire.5.2 ResistivityTh
23、e electrical resistivity at a temperature of 20C shall not exceed the values prescribed in Table 2. See Note2 for calculating electrical resistance.NOTE 2Relationships that may be useful in connection with the values of electrical resistivity prescribed in this specification are shown in Table 3.Res
24、istivity units 158 mm2/m and 0.15328 g/m2 at 20C are respectively the international equivalent of volume and weight resistivity of annealedTABLE 1 Wire SizesDiameter Cross-Sectional Area at 20C (68F)in. mm cmil in.2 mm20.0720 1.8129 5180 0.00407 2.630.0641 1.6128 4110 0.00323 2.080.0571 1.450 3260 0
25、.00256 1.650.0508 1.290 2580 0.00203 1.310.0453 1.151 2050 0.00161 1.040.0403 1.024 1620 0.00128 0.8230.0359 0.912 1290 0.00101 0.6530.0320 0.813 1020 0.000804 0.5190.0285 0.724 812 0.000638 0.4120.0253 0.643 640 0.000503 0.3240.0226 0.574 511 0.000401 0.2590.0201 0.511 404 0.000317 0.2050.0179 0.45
26、5 320 0.000252 0.1620.0159 0.404 253 0.000199 0.1280.0142 0.361 202 0.000158 0.1020.0126 0.320 159 0.000125 0.08040.0113 0.287 128 0.000100 0.06470.0100 0.254 100 0.0000785 0.05070.0089 0.226 79.2 0.0000622 0.04010.0080 0.203 64.0 0.0000503 0.03240.0071 0.180 50.4 0.0000396 0.02550.0063 0.160 39.7 0
27、.0000312 0.02010.0056 0.142 31.4 0.0000246 0.01590.0050 0.127 25.0 0.0000196 0.01270.0045 0.114 20.2 0.0000159 0.01030.0040 0.102 16.0 0.0000126 0.008110.0035 0.089 12.2 0.00000962 0.006210.0031 0.079 9.61 0.00000755 0.00487B520 122copper equal to 100 % conductivity. The latter term means that a cop
28、per wire 1 m in length and weighing 1 g would have a resistance of 0.15328 . Thisis equivalent to a resistivity value of 875.20 lb/mile 2, which signifies the resistance of a copper wire 1 mile in length weighing 1 lb. It is also equivalent,for example, to 1.7241 /cm of length of a copper bar 1 cm2
29、in cross section. A complete discussion of this subject is contained in NBS Handbook 100.The use of five significant figures in expressing resistivity does not imply the need for greater accuracy of measurement than that specified in Test MethodB193. The use of five significant figures is required f
30、or complete reversible conversion from one set of resistivity units to another.5.3 Dimensions and Permissible VariationsThe wire sizes shall be expressed as the diameter of the wire in decimal fractionsof an inch to the nearest 0.0001 in. (0.003 mm) (Note 3). For diameters under 0.0100 in. (0.254 mm
31、), the wire shall not vary fromthe specified diameter by more than plus 0.0003 in. (0.008 mm) and minus 0.0001 in. (0.003 mm) and for diameters of 0.0100 in.(0.254 mm) and over, the wire shall not vary from the specified diameter by more than plus 3 % and minus 1 %, expressed to thenearest 0.0001 in
32、. (0.003 mm).NOTE 3The values of the wire diameters in Table 1 are given to the nearest 0.0001 in. (0.003 mm) and correspond to the standard sizes given inSpecification B258. The use of gage numbers to specify wire sizes is not recognized in this specification because of the possibility of confusion
33、. Anexcellent discussion of wire gages and related subjects is contained in “Copper Wire Tables” NBS Handbook 100.5.4 Continuity of CoatingThe tin coating shall be continuous. The continuity of coating on the wire shall be determined onrepresentative samples taken before stranding or insulating. The
34、 continuity of tinning shall be determined by the hydrochloricacid-sodium polysulfide test in accordance with 6.2.5.5 Adherence of CoatingThe tin coating shall be firmly adherent to the surface of the copper-clad steel wire. The adherenceof coating on the wire shall be determined on representative s
35、amples taken before stranding or insulating. The adherence of coatingshall be determined by the wrapping and immersion test in accordance with 6.3.5.6 JointsNecessary joints in the wire and rods prior to final coating and drawing shall be made in accordance with goodcommercial practice. Joints made
36、after coating shall not be allowed to remain in the final product.5.7 FinishThe coating shall consist of a smooth, continuous layer, firmly adherent to the surface of the copper. The wire shallbe bright and free from all imperfections not consistent with good commercial practice.6. Test Methods6.1 F
37、or tensile strength, elongation, resistivity, dimensional measurement and the quality of the basis wire, the latest issue ofSpecification B452 shall apply and the tests shall be performed on the tin-coated wire.6.2 Continuity of Coating:6.2.1 Specimens:6.2.1.1 Length of SpecimensTest specimens shall
38、 each have a length of about 6 in. (150 mm). They shall be tagged or markedto correspond with the coil, spool, or reel from which they were cut.6.2.1.2 Treatment of SpecimensThe specimens shall be thoroughly cleaned by immersion in a suitable organic solvent suchas benzene, ether, or trichloroethyle
39、ne for at least 3 min, then removed and wiped dry with a clean, soft cloth. (WarningSee1.4.) The specimens thus cleaned shall be kept wrapped in a clean, dry cloth until tested. That part of the specimen to be immersedin the test solution shall not be handled. Care shall be taken to avoid abrasion b
40、y the cut ends.6.2.2 Special Solutions:6.2.2.1 Hydrochloric Acid Solution (sp gr 1.088)Commercial HCl (sp gr 1.12) shall be diluted with distilled water to a specificgravity of 1.088 measured at 15.6C (60F). A portion of HCl solution having a volume of 180 mL shall be considered to beexhausted when
41、the number of test specimens prescribed in Table 4 of a size as indicated in 6.2.3 have been immersed in it fortwo cycles.6.2.2.2 Sodium Polysulfide Solution (sp gr 1.142) (Note 4)A concentrated solution shall be made by dissolving sodium sulfidecp crystals in distilled water until the solution is s
42、aturated at about 21C (70F), and adding sufficient flowers of sulfur (in excessTABLE 2 Resistivity, max at 20CClass ofWireNominal Diameter, in.(mm) Vmm2/mT30HS 0.0720 (1.829) to 0.067430.0201 (0.511) incl (0.067427)and under 0.0201 (0.511) to 0.073150.0113 (0.287) incl (0.073148)T30A under 0.0113 (0
43、.287) to 0.076420.0031 (0.079) incl (0.076423)T40HS 0.0720 (1.829) to 0.048740.0201 (0.511) incl (0.048742)and under 0.0201 (0.511) to 0.051620.0113 (0.287) incl (0.051618)T40A under 0.0113 (0.287) to 0.053280.0031 (0.079) incl (0.053280)B520 123of 250 g/L of solution) to provide complete saturation
44、, as shown by the presence in the solution of an excess of sulfur after thesolution has been allowed to stand for at least 24 h. The test solution shall be made by diluting a portion of the concentratedsolution with distilled water to a specific gravity of 1.142 at 15.6C (60F). The sodium polysulfid
45、e test solution should havesufficient strength to blacken thoroughly a piece of clean untinned copper wire in 5 s. A portion of the The test solution used fortesting samples shall not be considered to be exhausted untilif it fails to blacken a piece of clean copper as described above.NOTE 4It is imp
46、ortant that the polysulfide solution be of proper composition and strength at the time of test. A solution which is not saturated withsulfur or which has been made from decomposed sodium sulfide crystals may give a false indication of failure. Therefore, the requirement that the solutionbe tested by
47、 observing its blackening effect on a bright copper wire is significant. Significant also is the requirement that the solution be saturated withsulfur by allowing the solution to stand at least 24 h after preparation. Attention is called also to the necessity for the use of sodium sulfide which hasn
48、ot deteriorated through exposure to air; and if exposure has occurred, the crystals should be tested for purity. The “Standard Reagents Tests” of theAmerican Chemical Society are useful in this connection.6.2.3 Procedure:6.2.3.1 Immersion of SpecimensImmerse a length of at least 412 in. (115 mm) fro
49、m each of the clean specimens, in accordancewith the following cycles, in test solutions maintained at a temperature between 15.6 and 21C (60 and 70F): (1) immerse thespecimen for 1 min in the HCl solution described in 6.2.2, wash, and wipe dry; (2) immerse the specimen for 30 s in the sodiumpolysulfide solution described in 6.2.2, wash, and wipe dry; (3) immerse the specimen for 1 min in the HCl solution, wash, andwipe dry; (4) immerse the specimen for 30 s in the sodium polysulfide solution, wash, and wipe dry.6.2.3.2 Wash
