ASTM B476-01(2012)
(Specification)Standard Specification for General Requirements for Wrought Precious Metal Electrical Contact Materials
Standard Specification for General Requirements for Wrought Precious Metal Electrical Contact Materials
ABSTRACT
This specification covers general requirements common to wrought precious metal electrical contact alloy products in the form of sheet, strip, wire, and rod. The raw material shall be of such quality and purity that the finished product shall have the properties and characteristics prescribed in the applicable product specification. The product shall be produced by a combination of hot or cold working operations, it shall be finished, unless otherwise specified, by cold working, annealing, or heat treatment as may be necessary to meet the specified properties. 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. Test methods such as chemical analysis and physical tests shall be performed accordingly.
SIGNIFICANCE AND USE
For purpose of determining compliance with the specified 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 E29.
PropertyUnitRounded Unit
for Observed or
Calculated Value Chemical compositionpercent 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 μΩ·cm Tensile strength psi (MPa)nearest 1000 psi (nearest 10
MPa) Yield Strength psi (MPa)nearest 1000 psi (nearest
10 MPa) Elongation Below 5 % percentnearest multiple of 0.5 % 5 % and over percentnearest 1 % Grain size Up to 0.055 mm incl. mmnearest multiple of 0.005
mm Over 0.055 to 0.160, mm, incl. mmnearest 0.01 mm
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 specification shall prevail in the sequence named.
1.3 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
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 become familiar with all hazards including those identified in the appropriate Material Safety Data Sheet (MSDS) for this product/material as provided by the manufacturer, to establish appropriate safety and health practices, and determine the applicability of regulatory limitations prior to use.
General Information
Relations
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:B476 −01(Reapproved 2012)
Standard Specification for
General Requirements for Wrought Precious Metal Electrical
Contact Materials
This standard is issued under the fixed designation B476; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript 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. Scope Resistance and Contact Materials
B772Guide for Specifying the Chemical Compositions for
1.1 This specification covers general requirements common
Electrical Contact Materials (Arcing and Nonarcing)
to wrought precious metal electrical contact alloy products in
E3Guide for Preparation of Metallographic Specimens
the form of sheet, strip, wire, and rod. Unless otherwise
E8Test Methods for Tension Testing of Metallic Materials
specifiedinthepurchaseorderorinanindividualspecification,
E29Practice for Using Significant Digits in Test Data to
these general requirements shall apply to wrought electrical
Determine Conformance with Specifications
contact materials where indicated in the applicable product
E55Practice for Sampling Wrought Nonferrous Metals and
specifications issued by ASTM.
Alloys for Determination of Chemical Composition
1.2 In case of conflict, the requirements on the purchase
E112Test Methods for Determining Average Grain Size
order, the individual specification, and this general specifica-
E384Test Method for Knoop and Vickers Hardness of
tion shall prevail in the sequence named.
Materials
1.3 The values stated in inch-pound units are to be regarded
3. Terminology
as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only
3.1 Definitions:
and are not considered standard.
3.1.1 lot, n—the quantity of material of the same type, size,
andfinishproducedatonetimefromthesamecastorheat,and
1.4 This standard does not purport to address all of the
heat treated in the same heat-treatment cycle.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to become familiar
4. Ordering Information
with all hazards including those identified in the appropriate
Material Safety Data Sheet (MSDS) for this product/material 4.1 Ordersformaterialtothisspecificationshallincludethe
as provided by the manufacturer, to establish appropriate following information:
safety and health practices, and determine the applicability of 4.1.1 Designation and revision date of this specification.
regulatory limitations prior to use. 4.1.1.1 Ifarevisiondateisnotdesignated,thelatestrevision
should be used.
2. Referenced Documents
4.1.2 Designation and revision date of the applicable prod-
uct specification.
2.1 The following documents of the issue in effect, on the
4.1.2.1 Ifarevisiondateisnotdesignated,thelatestrevision
date of material purchase, form a part of this specification to
of the product specification should be used.
the extent referenced herein:
4.1.3 Description of material form,
2.2 ASTM Standards:
4.1.4 Dimensions of the material,
B63Test Method for Resistivity of Metallically Conducting
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),
This specification is under the jurisdiction of ASTM Committee B02 on
4.1.8 Special requirements (if any), and
Nonferrous Metals and Alloys and is the direct responsibility of Subcommittee
B02.05 on Precious Metals and Electrical Contact Materials.
4.1.9 Certification (Section 14).
Current edition approved May 1, 2012. Published May 2012. Originally
4.2 Specify the following, if required:
approved in 1968. Last previous edition approved in 2006 as B476–01(2006).
DOI: 10.1520/B0476-01R12.
4.2.1 Certificate of compliance of physical and chemical
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
requirement.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
4.2.2 Test Data—Specifytestsandanalysestobeperformed
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. and reported.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B476−01(2012)
4.2.3 Special packaging, if required. purchaser.The following suggestion is to be used for guidance
only when the manufacturer and the purchaser discuss flatness
5. Materials and Manufacture
requirements. It is not a requirement of this specification,
unless agreed upon and made part of the purchase order or
5.1 Therawmaterialshallbeofsuchqualityandpuritythat
request for quotation. The flatness of a flat form shall be that
the finished product shall have the properties and characteris-
the maximum deviation from the flat surface shall be less than
ticsprescribedintheapplicableproductspecificationissuedby
1% of the measurement distance specified for the product,
ASTM.
such as diameter for circles, length or width of blanks, or any
5.2 The product shall be produced by a combination of hot
specific measurement length; that is, maximum of 0.20 in.
or cold working operations. it shall be finished, unless other-
(5.08 mm) deviation in any 20 in. (508 mm) length in any
wise specified, by such cold working, annealing, or heat
direction.
treatmentasmaybenecessarytomeetthespecifiedproperties.
7. Workmanship
6. Dimensions and Permissible Variations
7.1 Surfaces of all material furnished to this specification
6.1 General—For the purpose of determining conformance
shall be smooth, clean, and free from scratches, stains, rough
with the dimensional requirements prescribed in this
spots, slivers, laps, scale, pits, and any other injurious defects
specification,anymeasuredvalueoutsidethespecifiedlimiting
within limits consistent with the best possible practice.
values for any dimension may be cause for rejection.
6.2 Tolerance tables to cover all forms of products can
8. Sampling
become quite voluminous. For this reason, it is recommended
that tolerances be established and agreed upon between the 8.1 Sampling—Theportionsizeandselectionofpiecesshall
producer and user at the time of placing an order or an inquiry
be as follows:
for quotation of price and delivery. Refer to Section 16
8.1.1 Chemical Analysis—Samples for chemical analysis
(Supplementary Requirements). Details of form and tolerances
shall be taken and prepared in accordance with Practice E55.
for products not covered by this specification, such as, the
The minimum weight of the composite sample that is to be
types of materials listed below, and means of measurement,
divided into three equal parts shall be 6 g.
should be established between producer and user.
8.1.2 Physical Tests—For physical tests, a test specimen
6.2.1 Sawed products,
shall be taken from each of four randomly selected individual
6.2.2 Square sheared products,
units of finished product from a lot. If the lot consists of less
6.2.3 Flat wire, thickness, width and edge radius tolerances,
thanfourunits,apieceshallbetakenfromeachindividualunit.
6.2.4 Edge rolled flat wire, thickness, width and corner
radius tolerances.
9. Number of Tests and Retests
6.3 Wire and Rod:
9.1 If any specimen tested shows a defective test method or
6.3.1 The standard tolerances applied to the diameter of
extraneous flaws, it may be discarded and another specimen
wire and rod shall be as prescribed in Table 1.
substituted.
6.3.2 The rod straightness and length tolerance shall be
9.2 If the chemical analysis fails to conform to the specified
those prescribed in Table 2.
limits, analysis shall be made on a new composite sample,
6.4 Strip and Sheet—Supplied in the form of coils, flat
prepared from samples selected in accordance with Practice
lengths or on spools.
E55 or 8.1.2 after the physical tests have been performed. The
6.4.1 The thickness tolerances shall be those prescribed in
results of this retest shall comply with the specified require-
Table 3.
ments.
6.4.2 The width standard tolerance for slit products shall be
those prescribed in Table 4.
9.3 The required physical tests shall be performed on 2 of 4
6.4.3 The straightness (camber or edgewise curvature) tol- of the pieces selected in accordance with 8.1.2.
erance for slit strip is prescribed in Table 4 also.
9.3.1 If one of the two tests made to determine any of the
physicalpropertiesfailstomeetaspecifiedlimit,thistestshall
6.5 Flatness—Theflatnessofblanks,shims,circles,orother
be repeated on each of the two remaining pieces selected in
forms should be negotiated between the manufacturer and the
accordancewith8.1.2andtheresultsofbothofthesetestsshall
comply with the specified requirements.
TABLE 1 Round Wire and Rod Diameter Tolerance
9.4 In the case of micro hardness, the number of readings
Diameter, in. (mm) Tolerance, ±, in. (mm)
shall not be
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.