ASTM B267-90(2001)

Standard Specification for Wire for Use In Wire-Wound Resistors

SCOPE
1.1 This specification covers round wire and ribbon with controlled electrical properties for use in wire-wound resistance units and similar applications, but not for use as electrical heating elements.

General Information

• Status: Historical
• Publication Date: 31-Dec-2000
• ICS: 29.050 - Superconductivity and conducting materials
• Technical Committee: B02 - Nonferrous Metals and Alloys
• Drafting Committee: B02.10 - Thermostat Metals and Electrical Resistance Heating Materials

Relations

• Replaces: ASTM B267-90(1995)e1 - Standard Specification for Wire for Use In Wire-Wound Resistors
• Effective Date: 01-Jan-2001
• Replaced By: ASTM B267-07 - Standard Specification for Wire for Use In Wire-Wound Resistors
• Effective Date: 01-May-2007

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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: B 267 – 90 (Reapproved 2001)
Standard Specification for
1
Wire for Use In Wire-Wound Resistors
This standard is issued under the fixed designation B 267; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope 7. Nominal Electrical Resistance per Unit Length
1.1 This specification covers round wire and ribbon with 7.1 The nominal resistance per unit length for round wire
controlled electrical properties for use in wire-wound resis- shallbecalculatedfromthenominalresistivityandthenominal
tanceunitsandsimilarapplications,butnotforuseaselectrical cross-sectional area.
heating elements.
NOTE 1—When ribbon or flat wire is produced by rolling from round
wire, the cross section departs from that of a true rectangle by an amount
2. Referenced Documents
depending on the width-to-thickness ratio and the specific manufacturing
2.1 ASTM Standards:
practice. The conventional formula for computing ohms per foot and feet
perpoundistoconsiderthecrosssectionas17%lessthanatruerectangle
B63 Test Method for Resistivity of Metallically Conduct-
2
when width is more than 15 times the thickness and 6% less than a true
ing Resistance and Contact Materials
rectangle in other cases. This is not valid in view of modern rolling
B77 Test Method for Thermoelectric Power of Electrical-
equipment and practices, but still is widely used as a basis of description.
2
Resistance Alloys
Ribbonactuallyismadetoaspecifiedresistanceperfoot,andnotolerance
B84 Test Method for Temperature-Resistance Constants of
isspecifiedforthickness.Analternativeandacloserapproximationwould
2
Alloy Wires for Precision Resistors
be that for ribbon rolled round wire, the electrical resistance would be
calculated on a cross 6% less than a true rectangle.
3. Significance and Use
8. Temperature Coefficient of Resistance
3.1 This specification on wire and ribbon contains the
generic chemistry and requirements for resistivity, temperature 8.1 The change in resistance with change in temperature,
coefficient of resistance, thermal emf versus copper resistance expressed as the mean temperature coefficient of resistance
tolerances, and mechanical properties of bare wire, as well as basedonthereferencetemperatureof25°C,shallbewithinthe
thewireenamelsandinsulationsofalloysnormallyusedinthe limits specified in Table 1, Columns 4 and 6, over the
manufacture of wound resistors. corresponding temperature ranges specified in Columns 5 and
7. The mean temperature coefficient of resistance referred to
4. Alloy Classes
25°C is defined as the slope of a chord of an arc. This slope is
4.1 Fifteenclassesofalloysarecoveredbythisspecification
determined from the following equation:
as listed in Table 1.
6
a 5 ~DR/R DT! 310
m 25
5. Elongation
where:
5.1 The wire shall conform to the requirements for elonga-
a = mean temperature coefficient of resistance, ppm/
m
tionasprescribedinTable1,whentestedona10-in.(254-mm)
°C, Table 1, Columns 4 and 6,
length.
DR = change in resistance over temperature range indi-
cated in Table 1, Columns 5 and 7,
6. Resistivity
R = resistance at 25°C,
25
6.1 The bare wire shall conform to the requirements for DT = temperaturerangeindicatedinTable1,Columns5
and 7.
nominal resistivity as prescribed in Table 1.
6.2 Actual resistivity shall not vary from nominal resistivity 8.2 ForAlloyClasses1,2,and5,thetemperaturecoefficient
by more than 65% for Alloy Classes 1 to 4 inclusive, and as specified in Table 1 of any 10-ft (3-m) length shall not vary
610% for Alloy Classes 5 to 11 inclusive. more than 3 ppm/°C from that of any other 10-ft length on the
same spool or coil.
1
This test method is under the jurisdiction of ASTM Committee B02 on
Nonferrous Metals and Alloys and is the direct responsibility of Subcommittee
B02.10 on Thermostat Metals.
Current edition approved May 25, 1990. Published July 1990. Originally
published as B267–52 T. Last previous edition B267–83.
2
Annual Book of ASTM Standards, Vol 03.04.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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B 267
TABLE 1 Classes of Alloys and Requirements
Mean Temperature Coefficient of Resistance, a ppm for Maximum Thermal emf
m
Elongation in 10 in., min, %
B
° C Over Temperature Range,D T versus Copper, mV/°C
Resistivity,
Alloy Alloy Composition,
Over 0.002 to 0.0009
V·cmil/ft
A
D
Class approximate, %
Temperature 0.002 0.001 in. in
(µV·m)
DT a DT mV/°C
m C D D
Range, DT in. in in. in Diameter
Diameter Diameter and Finer
12 3 4 5 6 7 8 9 10 11 12
1a nickel base, nonmagnetic 800 (1.330)
...