ASTM B 476 – 90 R95

Designation: B 476 – 90 (Reapproved 1995)e1 An American National Standard Standard Specification for General Requirements for Wrought Precious Metal Electrical Contact Materials 1 This standard is issued under the fixed designation B 476; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval. This standard has been approved for use by agencies of the Department of Defense. Consult the DoD Index of Specifications and Standards for the specific year of issue which has been adopted by the Department of Defense. e1 NOTE—Section 17 was added editorially in June 1995. 1. Scope 1.1 This specification covers general requirements common to wrought precious metal electrical contact alloy products in the form of sheet, strip, wire, and rod. Unless otherwise specified in the purchase order or in an individual specification, these general requirements shall apply to wrought electrical contact materials where indicated in the applicable product specifications issued by ASTM. 1.2 In case of conflict, the requirements on the purchase order, the individual specification, and this general specifica- tion shall prevail in the sequence named. 1.3 The values stated in inch-pound units are to be regarded as the standard. The metric equivalents of inch-pound units may be approximate. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro- priate safety and health practices and determine the applica- bility of regulatory limitations prior to use. 1.5 It is the responsibility of the user to become familiar with all hazards including those identified in the appropriate Material Safety Data Sheet for this product/material as pro- vided by the manufacturer. 2. Referenced Documents The following documents of the issue in effect, on the date of material purchase, form a part of this specification to the extent referenced herein: 2.1 ASTM Standards: B 63 Test Method for Resistivity of Metallically Conduct- ing Resistance and Contact Materials2 B 277 Test Method for Hardness of Electrical Contact Materials2 E 3 Methods of Preparation of Metallographic Specimens3 E 8 Test Methods of Tension Testing of Metallic Materials3 E 29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications4 E 55 Practice for Sampling Wrought Nonferrous Metals and Alloys for Determination of Chemical Composition5 E 112 Test Methods for Determining Average Grain Size3 3. Terminology 3.1 Definition: 3.1.1 lot—the quantity of material of the same type, size, and finish produced at one time from the same cast or heat, and heat treated in the same heat-treatment cycle. 4. Ordering Information 4.1 Orders for material to this specification shall include the following information: 4.1.1 Designation and revision date of this specification. 4.1.1.1 If a revision date is not designated, the latest revision should be used. 4.1.2 Designation and revision date of the applicable prod- uct specification. 4.1.2.1 If a revision date is not designated, the latest revision of the product specification should be used. 4.1.3 Description of material form, 4.1.4 Dimensions of the material, 4.1.5 Total quantity of each size, 4.1.6 Temper of the material (annealed, cold worked, etc.), 4.1.7 Temper test (hardness or tensile) (Section 10), 4.1.8 Special requirements (if any), and 4.1.9 Certification (Section 14). 4.2 Specify the following, if required: 4.2.1 Certificate of compliance of physical and chemical requirement. 4.2.2 Test Data—Specify tests and analyses to be performed and reported. 4.2.3 Special packaging, if required. 1 This specification is under the jurisdiction of ASTM Committee B-4 on Metallic Materials for Thermostats and for Electrical Resistance, Heating, and Contacts and is the direct responsibility of Subcommittee B04.02 on Electrical Contact Materials. Current edition approved May 25, 1990. Published July 1990. Originally published as B476 –68. Last previous edition B476 – 85. 2 Annual Book of ASTM Standards, Vol 03.04. 3 Annual Book of ASTM Standards, Vol 03.01. 4 Annual Book of ASTM Standards, Vol 14.02. 5 Annual Book of ASTM Standards, Vol 03.05. 1 AMERICAN SOCIETY FOR TESTING AND MATERIALS 100 Barr Harbor Dr., West Conshohocken, PA 19428 Reprinted from the Annual Book of ASTM Standards. Copyright ASTM NOTICE:¬This¬standard¬has¬either¬been¬superseded¬and¬replaced¬by¬a¬new¬version¬or discontinued.¬Contact¬ASTM¬International¬(www.astm.org)¬for¬the¬latest¬information. 5. Materials and Manufacture 5.1 The raw material shall be of such quality and purity that the finished product shall have the properties and characteris- tics prescribed in the applicable product specification issued by ASTM. 5.2 The product shall be produced by a combination of hot or cold working operations. it shall be finished, unless other- wise specified, by such cold working, annealing, or heat treatment as may be necessary to meet the specified properties. 6. Dimensions and Permissible Variations 6.1 General—For the purpose of determining conformance with the dimensional requirements prescribed in this specifi- cation, any measured value outside the specified limiting values for any dimension may be cause for rejection. 6.2 Tolerance tables to cover all forms of products can become quite voluminous. For this reason, it is recommended that tolerances be established and agreed upon between the producer and user at the time of placing an order or an inquiry for quotation of price and delivery. Refer to Section 16 (Supplementary Requirements). Details of form and tolerances for products not covered by this specification, such as, the types of materials listed below, and means of measurement, should be established between producer and user. 6.2.1 Sawed products, 6.2.2 Square sheared products, 6.2.3 Flat wire, thickness, width and edge radius tolerances, 6.2.4 Edge rolled flat wire, thickness, width and corner radius tolerances. 6.3 Wire and Rod: 6.3.1 The standard tolerances applied to the diameter of wire and rod shall be as prescribed in Table 1. 6.3.2 The rod straightness and length tolerance shall be those prescribed in Table 2. 6.4 Strip and Sheet—Supplied in the form of coils, flat lengths or on spools. 6.4.1 The thickness tolerances shall be those prescribed in Table 3. 6.4.2 The width standard tolerance for slit products shall be those prescribed in Table 4. 6.4.3 The straightness (camber or edgewise curvature) tol- erance for slit strip is prescribed in Table 4 also. 6.5 Flatness—The flatness of blanks, shims, circles, or other forms should be negotiated between the manufacturer and the purchaser. The following suggestion is to be used for guidance only when the manufacturer and the purchaser discuss flatness requirements. It is not a requirement of this specification, unless agreed upon and made part of the pur- chase order or request for quotation. The flatness of a flat form shall be that the maximum deviation from the flat surface shall be less than 1 % of the measurement distance specified for the product, such as diameter for circles, length or width of blanks, or any specific measurement length; that is, maximum of 0.20 in. (5.08 mm) deviation in any 20 in. (508 mm) length in any direction. 7. Workmanship 7.1 Surfaces of all material furnished to this specification shall be smooth, clean, and free from scratches, stains, rough spots, slivers, laps, scale, pits, and any other injurious defects within limits consistent with the best possible practice. 8. Sampling 8.1 Sampling—The portion size and selection of pieces shall be as follows: 8.1.1 Chemical Analysis—Samples for chemical analysis shall be taken and prepared in accordance with Practice E 55. The minimum weight of the composite sample that is to be divided into three equal parts shall be 6 g. 8.1.2 Physical Tests—For physical tests, a test specimen shall be taken from each of four randomly selected individual units of finished product from a lot. If the lot consists of less than four units, a piece shall be taken from each individual unit. 9. Number of Tests and Retests 9.1 If any specimen tested shows a defective test method or extraneous flaws, it may be discarded and another specimen substituted. 9.2 If the chemical analysis fails to conform to the specified limits, analysis shall be made on a new composite sample, prepared from samples selected in accordance with Practice E 55 or 8.1.2 after the physical tests have been performed. The results of this retest shall comply with the specified require- ments. 9.3 The required physical tests shall be performed on 2 of 4 of the pieces selected in accordance with 8.1.2. 9.3.1 If one of the two tests made to determine any of the physical properties fails to meet a specified limit, this test shall be repeated on each of the two remaining pieces selected in accordance with 8.1.2 and the results of both of these tests shall comply with the specified requirements. 9.4 In the case of micro hardness, the number of readings shall not be less than 5 on each test specimen. 10. Test Methods 10.1 The properties enumerated in the applicable product specification shall be determined in accordance with the following: Test Methods B 63 and B 277, Methods E 3, E 8, and E 112, and Practice E 55. 11. Significance of Numerical Limits 11.1 For purpose of determining compliance with the speci- fied limits for requirements of the properties listed in the following table, an observed value or a calculated value shall be rounded as indicated in accordance with Practice E 29. TABLE 1 Round Wire and Rod Diameter Tolerance Diameter, in. (mm) Tolerance, 6, in. (mm) Up to 0.010 (0.25), incl 0.0001 (0.002) Over 0.010 to 0.020 (0.25 to 0.51), incl 0.0002 (0.005) Over 0.020 to 0.030 (0.51 to 0.76), incl 0.0003 (0.008) Over 0.030 to 0.040 (0.76 to 1.02), incl 0.0004 (0.010) Over 0.040 to 0.187 (1.02 to 4.75), incl 0.0005 (0.013) Over 0.187 to 0.250 (4.75 to 6.35), incl 0.001 (0.03) Over 0.250 to 0.375 (6.35 to 9.52), incl 0.0015 (0.04) Over 0.375 to 0.750 (9.52 to 19.0), incl 0.002 (0.05) B 476 2 Property Unit Rounded Unit for Observed or Calculated Value Chemical compositon percent Hardness Knoop (100-g load unless other- wise specified) Vicker (specify load) Rockwell (all scales, specify which) Rockwell superficial (all scales, specify which) nearest unit on the last right hand place of figure of specified limit Resistivity µV·cm Tensile strength psi (MPa) nearest 1000 psi (nearest 10 MPa) Yield Strength psi (MPa) nearest 1000 psi (nearest 10 MPa) Elongation Below 5 % percent nearest multiple of 0.5 % 5 % and over percent nearest 1 % Grain size Up to 0.055 mm incl. mm nearest multiple of 0.005 mm Over 0.055 to 0.160, mm, incl. mm nearest 0.01 mm 12. Inspection 12.1 The manufacturer shall afford the inspector represent- ing the purchaser, all reasonable facilities to satisfy him that the material is being furnished in accordance with this specifica- tion. 12.2 The manufacturer shall perform or have performed at least these minimum tests to ensure conformance to this specification: 12.2.1 Visual inspection at 13 for surface defects. All material shall be visually free from structural defects, cracks, seams, porosity, inclusions, segregation, and other defects described in 7.1. 12.2.1.1 If during 13 visual inspection an area of injurious defects is suspected, further inspection at 103 to 203 magni- fication is recommended to try to ascertain if the area in question is definitely defective as described in 7.1 and 12.2.1. 12.2.1.2 Although not required by the manufacturer, the purchaser may inspect the four randomly selected individual units chosen for physical tests in 8.1.2 for surface defects prior to performing the physical tests. An inspection at 103 to 203 magnification can be performed to look for defects described in 7.1 and 12.2.1. 12.2.1.3 If during visual inspection an injurious defect is suspected, a sample containing the defect may be mounted and suitably polished and etched. The sample may then be exam- ined at 503 magnification to determine if it meets the requirements listed in 7.1 and in 12.2.1. In no case shall any defect exceed 0.0005 in. (0.01 mm) in depth. 12.2.2 Hardness test or tension test can be applied, but not both unless specified by user. 12.2.3 Dimensional inspections shall be made as required to ensure conformance to tolerances specified. 12.2.4 Spectrographic or chemical analysis when required by order 13. Rejection 13.1 Material that fails to conform to this specification will be rejected, and the manufacturer shall be notified within 30 days after receipt of the material. 13.2 In the event of rejection, manufacturer and purchaser shall maintain test data and samples for not less than 6 weeks from the date of the test reports to resolve any disputed test results. 14. Certification 14.1 When specified in the purchase order or contract, the manufacturer’s or supplier’s certification shall be furnished to the purchaser stating that samples representing each lot have been manufactured, tested, and inspected in accordance with this specification and the requirements have been met. When specified in the purchase order or contract, a report of the test results shall be furnished. 15. Packaging and Package Marking 15.1 The material shall be separated by size, composition, and temper, and prepared for shipment in such a manner as to ensure acceptance by common carrier for transportation and to afford protection from the normal hazards of transportation. 15.2 Each shipping unit shall be legibly marked with the purchase order number, metal or alloy designation, temper, size, shape, gross and net weight, and name of supplier. The specification number shall be shown when specified. 16. Supplementary Requirements 16.1 Special tolerances other than those specified herein shall be as agreed upon by the manufacturer and purchaser. 16.2 Special requirements in analysis test procedures, toler- ances, properties, and quality shall be as agreed upon between manufacturer and purchaser. TABLE 2 Round Rod Straightness and Length Tolerance Length, ft (m) Straightness Tolerances Applicable to any longitudinal edge Maximum Curvature (Depth of Arc; in. (mm)) Length Tolerances Applicable only to full length pieces Length Tolerances in. (mm) Under 2 (0.6) 0.031 (0.78) 60.125 (3.18) 2 (0.6) and under 5 (1.5) 0.031 (0.78) in any 2-ft (0.6-m) portion of the total length. 60.125 (3.18) 5 (1.5) and under 10 (3.0) 0.125 (3.18) in any 5-ft (1.5-m) portion of the total length. 60.375 (9.52) 10 (3.0) and over 0.50 (12.7) in any 10-ft (3.0-m) portion of the total length. 60.500 (12.7) TABLE 3 Strip and Sheet Thickness Tolerance for Widths to 8.00 in. (203 mm) Inclusive Thickness, in (mm) ThicknessTolerance, 6, in. (mm) Up to 0.004 (0.10), incl 0.0003 (0.008) Over 0.004 to 0.006 (0.10 to 0.15), incl 0.0004 (0.010) Over 0.006 to 0.009 (0.15 to 0.23), incl 0.0006 (0.015) Over 0.009 to 0.013 (0.23 to 0.33), incl 0.0008 (0.020) Over 0.013 to 0.017 (0.33 to 0.43), incl 0.0010 (0.025) Over 0.017 to 0.021 (0.43 to 0.53), incl 0.0013 (0.033) Over 0.021 to 0.026 (0.53 to 0.66), incl 0.0015 (0.038) Over 0.026 to 0.050 (0.66 to 1.27), incl 0.002 (0.051) Over 0.050 to 0.073 (1.27 to 1.85), incl 0.0025 (0.064) Over 0.073 to 0.130 (1.85 to 3.30), incl 0.003 (0.076) Over 0.130 to 0.188 (3.30 to 4.77), incl 0.0035 (0.089) B 476 3 17. Keywords 17.1 contacts; electrical contact materials; wrought precious metal The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of 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 five years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, 100 Barr Harbor Drive, West Conshohocken, PA 19428. TABLE 4 Width and Edgewise Curvature Tolerances for Sheet and Strip, With Slit Edges Width Tolerances in Inches (mm) Edgewise Curvature Width Range Slit Metal Thickness Range Maximum Edgewise Curvature (depth of arc in any 6-ft (1.8-m) portion of the total length) over 0.002 to 0.016 (0.051 to 0.406) incl over 0.016 to 0.062 (0.406 to 1.57) incl over 0.062 to 0.125 (1.57 to 3.18) incl over 0.125 to 0.188 (3.18 to 4.78) incl Shipped in Rolls in. (mm) Shipped Flat in. (mm) 0.060 to 1.000 (1.52 to 25.4) incl 60.003 (0.076) 60.003 (0.076) 60.005 (0.127) 60.008 (0.203) 1.0 (25) 0.75 (19) over 1.000 to 2.000 (25.4 to 50.8) incl 60.003 (0.076) 60.003 (0.076) 60.008 (0.203) 60.012 (0.305) 0.6 (15) 0.50 (13) over 2.000 to 6.000 (50.8 to 152.4) incl 60.003 (0.076) 60.005 (0.127) 60.010 (0.254) 60.015 (0.381) 0.50 (13) 0.50 (13) over 6.000 to 8.000 (152.4 to 203) incl 60.005 (0.127) 60.008 (0.203) 60.013 (0.330) 60.015 (0.381) 0.38 (9.7) 0.38 (9.7) B 476 4 主营业务范围：ASTMASTMASTMASTM、NASNASNASNAS、NASMNASMNASMNASM、MILMILMILMIL、ISOISOISOISO、ENENENEN、 DINDINDINDIN、JISJISJISJIS等技术 标准 excel标准偏差excel标准偏差函数exl标准差函数国标检验抽样标准表免费下载红头文件格式标准下载 翻译；技术资料翻译；NADCAPNADCAPNADCAPNADCAP认证 标准资料翻译；国外技术标准中文版优惠低价代购等。 业务 QQQQQQQQ：2298175560229817556022981755602298175560 专业 专注于技术翻译 诚信 实惠 物超所值的服务可靠的质量保证