1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS 4393 : 1991 Incorporat
2、ing Amendment No. 1 ICS 29.060.10 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Specification for Solderable tin or tin-lead coated wires for component terminationsBS 4393 : 1991 Issue 2, March 1998 This British Standard, having been prepared under the direction of the Non-f
3、errous Metals Standards Policy Committee, was published under the authority of the Standards Board and comes into effect on 30 April 1991 BSI 1998 First published January 1969 Second edition April 1991 The following BSI references relate to the work on this standard: Committee reference NFM/27 Draft
4、 for comment 88/45505 DC ISBN 0 580 19185 0 Amendments issued since publication Amd. No. Date T ext affected 9922 March 1998 Indicated by a sideline in the margin Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Non-ferrous Metals Standar
5、ds Policy Committee (NFM/-) to T echnical Committee NFM/27, upon which the following bodies were represented: Association of British Pewter Craftsmen British Steel Industry EEA - the Electronics and Business Equipment Association International Tin Research Institute London Metal Exchange Metal Packa
6、ging Manufacturers Association Ministry of Defence Solder Makers Association Coopted members The following bodies were also represented in the drafting of the standard, through subcommittees and panels: British Plumbing Fittings Manufacturers Association T elecommunication Engineering and Manufactur
7、ing AssociationIssue 2, July 1998 BS 4393 : 1991 BSI 1998 a Summary of pages The following table identifies the current issue of each page. Issue 1 indicates that a page has been introduced for the first time by amendment. Subsequent issue numbers indicate an updated page. Vertical sidelining on rep
8、lacement pages indicates the most recent changes (amendment, addition, deletion). Page Issue Page Issue Front cover Inside front cover a b 1 2 3 4 5 6 2 2 2 blank 2 2 original original 3 2 7 8 9 10 11 12 13 14 Inside back cover Back cover original original original original original original origina
9、l original original 2b blankIssue 2, March 1998 BS 4393 : 1991 BSI 1998 1 | Contents Page Committees responsible Inside front cover Foreword 2 Specification 1 Scope 3 2 Definitions 3 3 Materials 3 4 Solderability 5 5 Dimensions and tolerances 5 6 Bend test for robustness of termination 5 7 Elongatio
10、n 6 8 Bend test for coating adhesion 6 9 Sampling 6 10 Packaging and labelling 6 Appendices A Information to be supplied by the purchaser 7 B Methods for use in cases of dispute for the determination of the thickness of tin and tin-lead coating and undercoat 7 C Method for use in cases of dispute fo
11、r the determination of the composition of tin and tin-lead coatings by atomic absorption spectrophotometry 8 D Method for the detection of lead in tin and tin-lead coatings 10 E Method for bend test 11 F Guidance notes to aid selection of suitable basis wire and coatings for component terminations 1
12、2 Tables 1 Composition of the preferred tin or tin-lead solderable coatings 4 2 Average thickness for solderable coating 5 3 Density of tin-lead alloys 8 4 Calibration solutions 9 Figures 1 Rotor head for bend tester 11 2 Arrangement of bend test apparatus 12BS 4393 : 1991 Issue 2, March 1998 2 BSI
13、1998 | | Foreword This British Standard has been prepared under the direction of the Non-ferrous Metals Standards Policy Committee. It is a revision of BS 4393 : 1969 which is withdrawn. Unlike the 1969 edition, which specified copper only as the basis wire, this revision covers coated wires having
14、basis wires in a range of materials including copper , nickel, steel, steel undercoated with nickel or copper , brass, nickel-copper alloy, phospor bronze and nickel silver . As a result of this change in the basis wire materials, performance requirements in this revision differ markedly from those
15、in the 1969 edition. Included in this revision is appendix F which gives guidance notes to aid the user in the selection of the most appropriate wires and coatings for particular applications. The initial draft from which this revision was developed was prepared by a working group set up by the Elec
16、tronics and Business Equipment Association. A British Standard does not purport to include all necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations.3
17、BS 4393 : 1991 Specification 1 Scope This British Standard specifies requirements for the solderability, mechanical properties, sampling, packaging and materials of manufacture for tin and tin-lead coated wire. It applies to coated wire which is primarily intended for component leads in the electron
18、ics industry , where good solderability is the main criterion, and where the basis wire has a nominal diameter within the range 0.25 mm to 1.20 mm. A range of materials is specified for the basis wire. Details of information to be supplied by the purchaser are given in appendix A. The coating thickn
19、ess range, necessary to achieve good solderability, is specified. T est methods, particularly for use in cases of dispute, for the measurement of coating thickness, for the determination of the tin content of the coating and for the detection of lead in the coating are given in appendices B, C and D
20、 respectively. Appendix E gives the method for carrying out the bend test, which is used for assessing the robustness of the termination and for the coating adhesion. NOTE 1. Guidance notes to assist the purchaser/user in the selection of the most appropriate basis wire and coating are given in appe
21、ndix F . NOTE 2. The titles of the publications referred to in this standard are listed on the inside back cover . 2 Definitions For the purposes of this British Standard the following definitions apply. 2.1 basis wire The underlying wire to which the undercoat and/or the tin or tin-lead solderable
22、coating is applied. 2.2 undercoat A metallic coat applied to the basis wire before the application of the tin or tin-lead solderable coating, in order to prevent diffusion from the basis wire, or to improve the adhesion of the solderable coating. NOTE. An example is an undercoat of copper or nickel
23、on brass or nickel-silver basis wire, to prevent diffusion of zinc into the solderable coating. 2.3 solderable coating The final coat of tin or tin-lead applied to the basis wire, with or without an undercoat, to render the wire solderable, when tested in accordance with clause 4 of this standard. 2
24、.4 flow-melting A process by which a coating is melted in order to impart desirable properties, such as brightness or improved solderability. NOTE. Less-preferred terms applicable to this definition are fusing, flow-brightening and re-flowing. 2.5 unit of product The unit of product is the item insp
25、ected in order to determine its compliance with this British Standard. The unit of product used for the sampling of tin or tin-lead coated wire for component terminations is a single reel or pay-off pack. 2.6 batch A collection of units of product from one continuous manufacturing run from which a s
26、ample is to be drawn and inspected in order to determine compliance with this British Standard. 2.7 average coating thickness The coating thickness calculated from the loss in mass when the coating is stripped from a sample of the wire of known surface area. 2.8 local coating thickness The mean of a
27、t least 10 thickness measurements, taken at varying longitudinal and radial positions along a 1 m length of wire. 3 Materials 3.1 Basis wire 3.1.1 General The basis wire used in the manufacture of the coated wire in accordance with this British Standard shall comply with one of the materials given i
28、n 3.1.2 to 3.1.10. NOTE. The purchaser should state on his enquiry and/or order the basis wire required selected from 3.1.2 to 3.1.10 (see item (b) of appendix A). 3.1.2 Copper Copper wire complying with BS 4109, O condition in copper grades C101, C102 or C103. NOTE. The purchaser should state on hi
29、s enquiry and/or order which grade is required (see item (c) of appendix A). 3.1.3 Nickel Nickel wire complying with BS 3075, grade NA11 in the cold drawn and annealed condition. 3.1.4 Steel Low carbon annealed steel wire complying with BS 1052, but having a maximum carbon content of 0.15 % and a ma
30、ximum manganese content of 0.60 %. 3.1.5 Copper coated steel Consisting of steel wire, as in 3.1.4, coated with an adherent, ductile copper coating having a thickness of at least 3mm. NOTE. The specified copper coating thickness is only to enhance the solderability and does not significantly improve
31、 the conductivity of the termination. For special applications, e.g. those requiring a higher conductivity, wire having a copper coating thickness greater than 3mm may be supplied, subject to agreement between the purchaser and the supplier . In these circumstances the coating thickness required sho
32、uld be stated by the purchaser in the enquiry and/or order (see item (d) of appendix A).BS 4393 : 1991 4 3.1.6 Nickel coated steel Consisting of steel wire, as in 3.1.4, coated with an adherent, ductile nickel coating having a thickness of at least 3mm. NOTE. If electroplated, the nickel coating may
33、 be preceded by an electrolytic copper coat, subject to agreement between the purchaser and the supplier . 3.1.7 Nickel-copper alloy Nickel-copper alloy wire complying with BS 3075, grade NA13 in the cold drawn and annealed condition. 3.1.8 Brass Brass (copper-zinc) wire complying with BS 2873, O co
34、ndition, alloy CZ106, or for special applications, other alloys complying with BS 2873, e.g. CZ101, CZ102, CZ103, CZ107 or CZ108. NOTE 1. The purchaser should state on his enquiry and/or order whether CZ106 or another brass alloy (for special applications) is required (see item (e) of appendix A). N
35、OTE 2. See 3.2 concerning undercoats for tin or tin-lead coatings on basis wires containing zinc. 3.1.9 Phosphor bronze Phosphor bronze (copper-tin-phosphorus) wire complying with BS 2873, O condition, in alloys PB102 or PB103. NOTE. The purchaser should state on his enquiry and/or order whether PB1
36、02 or PB103 is required (see item (f) of appendix A). 3.1.10 Nickel silver Nickel silver (copper-nickel-zinc) wire complying with BS 2873, O condition, in alloys NS104 or NS106. NOTE 1. The purchaser should state on his enquiry and/or order whether NS104 or NS106 is required (see item (g) of appendi
37、x A). NOTE 2. See 3.2 concerning undercoats for tin or tin-lead coatings on basis wires containing zinc. 3.2 Undercoats Basis wires containing zinc (i.e. 3.1.8 and 3.1.10) shall be plated with an undercoat of nickel or copper , which acts as a barrier layer to prevent zinc diffusion through the sold
38、erable coating. This undercoat shall be adherent, ductile, continuous and, when measured in accordance with B.3, shall have a local thickness of at least 3mm. NOTE. Basis wires in materials 3.1.2 to 3.1.6 should be coated directly with the tin or tin-lead solderable coating. Wires in materials 3.1.7
39、 and 3.1.9 may require an undercoat of copper or nickel to improve the adhesion of the subsequent solderable coating. If such an undercoat is required, then the details, including its thickness, should be agreed between the purchaser and the supplier and stated in the enquiry and/or order (see item
40、(h) of appendix A). 3.3 Tin or tin-lead solderable coating 3.3.1 Coating composition The composition of the solderable coating shall comply with either: (a) one of the preferred alloys given in table 1; or (b) a non-preferred alloy containing a quantity of tin within 5 % of the nominal value specifi
41、ed by the purchaser . Table 1. Composition of the preferred tin or tin-lead solderable coatings Coating description Composition Tin Lead %( m / m)% ( m / m ) Sn100 99 min. - Sn95-Pb 93 to 97 remainder Sn60-Pb 55 to 65 remainder Sn30-Pb 25 to 35 remainder NOTE 1. Table 1 gives the preferred compositi
42、ons for tin and tin-lead solderable coatings. The compsitional requirements for non-preferred alloys should be agreed between the purchaser and the supplier and should be clearly stated in the enquiry and/or order (see item (i) in appendix A). NOTE 2. A suitable method for determining the tin conten
43、t of the coating is given in appendix C and should be used in case of dispute. A test method for the detection of lead, to differentiate between the pure tin and the tin-lead coatings, is given in appendix D. 3.3.2 Coating method The solderable coating shall be applied by either hot-dipping or elect
44、roplating. NOTE 1. The purchaser should state in his enquiry and/or order which coating method is required (see item (j) of appendix A). NOTE 2. Electroplated coatings may be flow-melted, subject to agreement between the purchaser and the supplier (see F. 5 ). 3.3.3 Average coating thickness The ave
45、rage thickness of the solderable coating when measured in accordance with B.2 shall comply with the limits given in table 2. T able 2. Average thickness for solderable coating Basis wire or undercoat Average thickness of solderable coating Minimum Maximum mm mm Copper 51 2 Phosphor bronze Nickel Ste
46、el 4 12 Nickel-copperIssue 3, July 1998 BS 4393 : 1991 BSI 1998 5 | | | | | | | | | | | | | | | | 4 Solderability 4.1 General Coated wire shall, after ageing in accordance with 4.2, comply with the solderability requirements given in 4.3 and 4.4. In addition, samples having plated coatings which hav
47、e not been flow-melted shall comply with the outgassing test given in 4.5. When tests are carried out on a batch of coated wires to verify compliance with the solderability requirements, the test samples shall be selected in accordance with clause 9. The solderability tests shall be carried out on f
48、ive specimens from each sample length selected. 4.2 Ageing Before testing, the specimens shall be aged by one of the following procedures, according to the basis wire material. (a) For coated wires having basis wire materials 3.1.8 and 3.1.10. Age in steam, in accordance with 4.5.1 and 4.5.4 of BS 2
49、011 : Part 2.1T : 1981, but using 24 h instead of 1 h or 4 h. This procedure promotes zinc diffusion from the zinc containing basis wire. (b) For coated wires having a basis wire material other than 3.1.8 or 3.1.10. Age for 16 h in dry heat at 155 C, in accordance with 4.5.3 and 4.5.4 of BS 2011 : Part 2.1T : 1981. 4.3 Globule test 4.3.1 For basis wire of copper (3.1.2) only When tested in accordance with 4.8 of BS 2011 : Part 2.1T : 1981, using the non-activated flux, the soldering time as defined in 4.8.4 of that standard shall not exceed 1.5 s or the nu
