ASTM B267-07(2018)

Standard Specification for Wire for Use In Wire-Wound Resistors

ABSTRACT
This specification covers round wires and ribbons with controlled electrical properties made from magnetic and nonmagnetic class 1a-11 alloys. The wires and ribbons, which may have insulated coverings or enamel coatings, are recommended for use in wire-wound resistance units like precision resistors and other similar applications, but not for use as electrical heating elements. Each bare wire should conform to the requirements for nominal resistivity, elongation, thermal electromotive force with respect to copper, and the temperature coefficient of resistance contained in this specification. The nominal resistance per unit length for a round wire is calculated from the nominal resistivity and nominal cross-sectional area.
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.  
1.2 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.  
1.3 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 Safety Data Sheet (SDS) for this product/material as provided by the manufacturer, to establish appropriate safety, health, and environmental practices, and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Historical
• Publication Date: 31-Mar-2018
• 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 B267-07(2013) - Standard Specification for Wire for Use In Wire-Wound Resistors
• Effective Date: 01-Apr-2018
• Replaced By: ASTM B267-07(2023) - Standard Specification for Wire for Use In Wire-Wound Resistors
• Effective Date: 01-Nov-2023
• Refers: ASTM B84-07(2019) - Standard Test Method for Temperature-Resistance Constants of Alloy Wires for Precision Resistors
• Effective Date: 01-Apr-2019
• Refers: ASTM B77-07(2018) - Standard Test Method for Thermoelectric Power of Electrical-Resistance Alloys
• Effective Date: 01-Nov-2018
• Refers: ASTM B77-07(2013) - Standard Test Method for Thermoelectric Power of Electrical-Resistance Alloys
• Effective Date: 01-May-2013
• Refers: ASTM B84-07(2013) - Standard Test Method for Temperature-Resistance Constants of Alloy Wires for Precision Resistors
• Effective Date: 01-May-2013
• Refers: ASTM B63-07(2013) - Standard Test Method for Resistivity of Metallically Conducting Resistance and<brk/> Contact Materials
• Effective Date: 01-May-2013
• Refers: ASTM B84-07 - Standard Test Method for Temperature-Resistance Constants of Alloy Wires for Precision Resistors
• Effective Date: 01-May-2007
• Refers: ASTM B63-07 - Standard Test Method for Resistivity of Metallically Conducting Resistance and Contact Materials
• Effective Date: 01-May-2007
• Refers: ASTM B77-07 - Standard Test Method for Thermoelectric Power of Electrical-Resistance Alloys
• Effective Date: 01-May-2007
• Refers: ASTM B63-90(2001) - Standard Test Method for Resistivity of Metallically Conducting Resistance and Contact Materials
• Effective Date: 01-Jan-2001
• Refers: ASTM B84-90(2001) - Standard Test Method for Temperature-Resistance Constants of Alloy Wires for Precision Resistors
• Effective Date: 01-Jan-2001
• Refers: ASTM B77-81(2001) - Standard Test Method for Thermoelectric Power of Electrical-Resistance Alloys
• Effective Date: 01-Jan-2001

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation:B267 −07 (Reapproved 2018)
Standard Specification for
Wire for Use In Wire-Wound Resistors
This standard is issued under the fixed designation B267; 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.
1. Scope 3. Significance and Use
3.1 This specification on wire and ribbon contains the
1.1 This specification covers round wire and ribbon with
generic chemistry and requirements for resistivity, temperature
controlled electrical properties for use in wire-wound resis-
coefficient of resistance, thermal emf versus copper resistance
tanceunitsandsimilarapplications,butnotforuseaselectrical
tolerances, and mechanical properties of bare wire, as well as
heating elements.
thewireenamelsandinsulationsofalloysnormallyusedinthe
1.2 The values stated in inch-pound units are to be regarded
manufacture of wound resistors.
as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only
4. Alloy Classes
and are not considered standard.
4.1 Fifteenclassesofalloysarecoveredbythisspecification
1.3 This standard does not purport to address all of the
as listed in Table 1.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to become familiar
5. Elongation
with all hazards including those identified in the appropriate
5.1 The wire shall conform to the requirements for elonga-
Safety Data Sheet (SDS) for this product/material as provided
tionasprescribedinTable1,whentestedona10-in.(254-mm)
by the manufacturer, to establish appropriate safety, health,
length.
and environmental practices, and determine the applicability
of regulatory limitations prior to use.
6. Resistivity
1.4 This international standard was developed in accor-
6.1 The bare wire shall conform to the requirements for
dance with internationally recognized principles on standard-
nominal resistivity as prescribed in Table 1.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
6.2 Actualresistivityshallnotvaryfromnominalresistivity
mendations issued by the World Trade Organization Technical by more than 65% for Alloy Classes 1 to 4 inclusive, and
Barriers to Trade (TBT) Committee.
610% for Alloy Classes 5 to 11 inclusive.
7. Nominal Electrical Resistance per Unit Length
2. Referenced Documents
7.1 The nominal resistance per unit length for round wire
2.1 ASTM Standards:
shallbecalculatedfromthenominalresistivityandthenominal
B63Test Method for Resistivity of Metallically Conducting
cross-sectional area.
Resistance and Contact Materials
B77Test Method for Thermoelectric Power of Electrical-
NOTE 1—When ribbon or flat wire is produced by rolling from round
Resistance Alloys wire, the cross section departs from that of a true rectangle by an amount
depending on the width-to-thickness ratio and the specific manufacturing
B84Test Method for Temperature-Resistance Constants of
practice. The conventional formula for computing ohms per foot and feet
Alloy Wires for Precision Resistors
perpoundistoconsiderthecrosssectionas17%lessthanatruerectangle
when width is more than 15 times the thickness and 6% less than a true
rectangle in other cases. This is not valid in view of modern rolling
equipment and practices, but still is widely used as a basis of description.
This specification is under the jurisdiction of ASTM Committee B02 on
Ribbonactuallyismadetoaspecifiedresistanceperfoot,andnotolerance
Nonferrous Metals and Alloys and is the direct responsibility of Subcommittee
isspecifiedforthickness.Analternativeandacloserapproximationwould
B02.10 on Thermostat Metals and Electrical Resistance Heating Materials.
be that for ribbon rolled round wire, the electrical resistance would be
Current edition approved April 1, 2018. Published April 2018. Originally
calculated on a cross 6% less than a true rectangle.
approved in 1952. Last previous edition approved in 2013 as B267– 07 (2013).
DOI: 10.1520/B0267-07R18.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or 8. Temperature Coefficient of Resistance
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
8.1 The change in resistance with change in temperature,
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. expressed as the mean temperature coefficient of resistance
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B267−07 (2018)
TABLE 1 Classes of Alloys and Requirements
Mean Temperature Coefficient of Resistance, α ppm for Maximum Thermal emf
m
Elongation in 10 in., min, %
B
°C Over Temperature Range,∆ T versus Copper, mV/°C
Resistivity,
Alloy Alloy Composition,
Over 0.002 to
0.0009
Ω·cmil/ft
A
Class approximate, % D
Temperature 0.002 0.001
in. in
(µΩ·m)
∆T α ∆T mV/°C
m C
D D
Range, ∆T Diameter
in. in in. in
and Finer
Diameter Diameter
12 3 4 5 6 7 8 9 10 11 12
1a nickel base, nonmagnetic 800 (1.330) 0, ±20 +25 to −55 0, ±20 +25 to +105 +0.003 −65 to +250 10 5 3
1b nickel base, nonmagnetic 800 (1.330) 0, ±10 +25 to −55 0, ±10 +25 to +105 +0.003 −65 to +150 10 5 3
1c nickel base, nonmagnetic 800 (1.330) 0, ±5 +25 to −55 0, ±5 +25 to +105 +0.003 −65 to +150 10 5 3
2a iron base, magnetic 800 (1.330) 0, ±20 +25 to −55 0, ±20 +25 to +105 −0.004 −65 to +200 10 5 3
2b iron base, magnetic 800 (1.330) 0, ±10 +25 to −55 0, ±10 +25 to +105 −0.004 −65 to +150 10 5 3
3a 80 nickel, 20 chromium 650 (1.081) +80, ±20 +25 to −55 +80, ±20 +25 to +105 +0.006 −65 to +250 15 5 3
3b 80 nickel, 20 chromium, 675 (1.122) +60, ±20 +25 to −55 +60, ±20 +25 to +105 +0.006 −65 to +250 15 5 3
stabilized
4 60 nickel, 16 chromium, 675 (1.122) +140, ±30 +25 to −55 +140, ±30 +25 to +105 +0.002 −65 to +200 15 5 3
balance iron
5a 55 copper, 45 nickel 300 (0.499) 0, ±20 +25 to −55 0, ±20 +25 to +105 −0.045 −65 to + 150 15 5 3
5b 55 copper, 45 nickel 300 (0.499) 0, ±40 +25 to −55 0, ±40 +25 to +105 −0.045 −65 to +150 15 5 3
EE EE
6 manganin type 290 (0.482) 0, ±15 0, ±15 −0.003 +15 to +35 15 5 3
7 77 copper, 23 nickel 180 (0.299) +180, ±30 +25 to −55 +180, ±30 +25 to +105 −0.037 −65 to +150 15 5 3
8 70 nickel, 30 iron 125 (0.199) +3600, ±400 +25 to −50 +4300, ±400 +25 to +104 −0.040 −50 to +100 15 5 3
9 90 copper, 10 nickel 90 (0.150) +450, ±50 +25 to −55 +450, ±50 +25 to +105 −0.026 −65 to +150 15 5 3
10 94 copper, 6 nickel 60 (0.100) +700, ±200 +25 to −55 +700, ±200 +25 to +105 −0.022 −65 to +150 15 5 3
11 98 copper, 2 nickel 30 (0.050) +1400, ±300 +25 to −55 +1400, ±300 +25 to +105 0.014 −65 to +150 15 5 3
A
Alloy Classes 1a to 8 inclusive are designed to provide controlled temperature coefficients. Values shown for other classes are for information only. All values are based
on a reference temperature of 25°C.
B
Alloy Classes 1a, 1b, 1c, 2a, 2b, 3a, 4, and 6 are designed to give a low emf versus copper. Values shown for other classes are for information only. Maximum indicates
the maximum deviation from zero and the plus or minus sign the polarity of the couple.
C
The maximum temperature values listed apply to the alloy wire only. Caution should be exercised pending knowledge of the maximum temperature of use for the coating
material involved.
D
If metric sizes are desired, 1 in. = 25.4 mm.
E
Alloy Class 6 (manganin type for resistors), has a temperature-resistance curve of parabolic shape with the maximum resistance normally located between 25 and 30°C.
m
Thus, Columns 5 and 7 cannot indicate 25°C as a limit butα may be expressed as a maximum of +15 ppm for 15°C to the temperature of maximum resistance and a
maximum of −15 ppm from the temperature of maximum resistance to 35°C. All of the information included in this note is based on measurements made in accordance
with Test Method B84.
A
TABLE 2 Dimensions of Enamel Coated Wire
Nominal Bare Wire Size Light Coated Wire Medium Coated Wire Heavy Coated Wire
Outside Diameter, Outside Diameter, Outside Diameter, Outside Diameter, Outside Diameter, Outside Diameter,
B&S Gage No. Diameter, in.
min, in. max, in. min, in. max, in. min, in. max, in.
28 0.0126 0.0130 0.0134 0.0134 0.0139 0.0139 0.0144
29 0.0113 0.0116 0.0120 0.0120 0.0125 0.0125 0.0130
30 0.010 0.0103 0.0107 0.0107 0.0112 0.0112 0.0116
31 0.0089 0.0092 0.0096 0.0096 0.0100 0.0100 0.0103
32 0.008 0.0083 0.0086 0.0086 0.0090 0.0090 0.0093
33 0.0071 0.0073 0.0076 0.0076 0.0080 0.0080 0.0083
34 0.0063 0.0064 0.0067 0.0067 0.0071 0.0071 0.0074
35 0.0056 0.0057 0.0060 0.0060 0.0064 0.0064 0.0067
36 0.005 0.0051 0.0054 0.0054 0.0057 0.0057 0.0060
37 0.0045 0.0046 0.0049 0.0049 0.0052 0.0052 0.0055
38 0.004 0.0041 0.0043 0.0043 0.0046 0.0046 0.0049
39 0.0035 0.0036 0.0038 0.0038 0.0041 0.0041 0.0043
40 0.0031 0.0032 0.0034 0.0034 0.0037 0.0037 0.0039
0.00275 0.0029 0.0031 0.0031 0.0033 0.0033 0.0035
0.0025 0.0026 0.0028 0.0028 0.0030 0.0030 0.0032
0.00225 0.00235 0.0025 0.0025 0.0027 0.0027 0.0029
0.002 0.0021 0.0022 0.0022 0.0024 0.0024 0.0026
0.00175 . 0.0019 0.0019 0.0021 0.0021 0.0023
0.0015 . 0.0016 0.0016 0.0018 0.0018 0.0020
0.0014 . 0.0015 0.0015 0.0017 0.0017 0.0019
0.0013 . 0.0014 0.0014 0.0016 0.0016 0.0018
0.0012 . 0.0013 0.0013 0.0015 0.0015 0.0017
0.0011 . 0.0012 0.0012 0.0014 0.0014 0.0016
0.001 . 0.0011 0.0011 0.0013 0.0013 0.0015
0.0009 . 0.0010 0.0010 0.0012 0.0012 0.0014
0.0008 . 0.0009 0.0009 0.0010 0.0010 0.0012
0.0007 . 0.0008 0.0008 0.0009 0.0009 0.0010
0.0006 . 0.0007 0.0007 0.0008 0.0008 0.0009
0.0005 . 0.0006 0.0006 0.0007 0.0007 0.0008
A
To convert from inches to millimetres multiply by 25.4.
B267−07 (2018)
basedonthereferencetemperatureof25°C,shallbewithinthe 13. Enamel Coatings
limits specified in Table 1, Columns 4 and 6, over the
13.1 Enamel coatings shall include any baked-on film of
corresponding temperature ranges specified in Columns 5 and
insulating material, such as varnish enamel, polyurethane,
7. The mean temperature coefficient of resistance referred to
vinyl acetal, etc. and shall con
...

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: B267 − 07 (Reapproved 2018)
Standard Specification for
Wire for Use In Wire-Wound Resistors
This standard is issued under the fixed designation B267; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3. Significance and Use
3.1 This specification on wire and ribbon contains the
1.1 This specification covers round wire and ribbon with
generic chemistry and requirements for resistivity, temperature
controlled electrical properties for use in wire-wound resis-
coefficient of resistance, thermal emf versus copper resistance
tance units and similar applications, but not for use as electrical
tolerances, and mechanical properties of bare wire, as well as
heating elements.
the wire enamels and insulations of alloys normally used in the
1.2 The values stated in inch-pound units are to be regarded
manufacture of wound resistors.
as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only
4. Alloy Classes
and are not considered standard.
4.1 Fifteen classes of alloys are covered by this specification
1.3 This standard does not purport to address all of the
as listed in Table 1.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to become familiar
5. Elongation
with all hazards including those identified in the appropriate
5.1 The wire shall conform to the requirements for elonga-
Safety Data Sheet (SDS) for this product/material as provided
tion as prescribed in Table 1, when tested on a 10-in. (254-mm)
by the manufacturer, to establish appropriate safety, health,
length.
and environmental practices, and determine the applicability
of regulatory limitations prior to use.
6. Resistivity
1.4 This international standard was developed in accor-
6.1 The bare wire shall conform to the requirements for
dance with internationally recognized principles on standard-
nominal resistivity as prescribed in Table 1.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom- 6.2 Actual resistivity shall not vary from nominal resistivity
mendations issued by the World Trade Organization Technical
by more than 65 % for Alloy Classes 1 to 4 inclusive, and
Barriers to Trade (TBT) Committee. 610 % for Alloy Classes 5 to 11 inclusive.
7. Nominal Electrical Resistance per Unit Length
2. Referenced Documents
7.1 The nominal resistance per unit length for round wire
2.1 ASTM Standards:
shall be calculated from the nominal resistivity and the nominal
B63 Test Method for Resistivity of Metallically Conducting
cross-sectional area.
Resistance and Contact Materials
B77 Test Method for Thermoelectric Power of Electrical-
NOTE 1—When ribbon or flat wire is produced by rolling from round
Resistance Alloys wire, the cross section departs from that of a true rectangle by an amount
depending on the width-to-thickness ratio and the specific manufacturing
B84 Test Method for Temperature-Resistance Constants of
practice. The conventional formula for computing ohms per foot and feet
Alloy Wires for Precision Resistors
per pound is to consider the cross section as 17 % less than a true rectangle
when width is more than 15 times the thickness and 6 % less than a true
rectangle in other cases. This is not valid in view of modern rolling
equipment and practices, but still is widely used as a basis of description.
This specification is under the jurisdiction of ASTM Committee B02 on
Ribbon actually is made to a specified resistance per foot, and no tolerance
Nonferrous Metals and Alloys and is the direct responsibility of Subcommittee
is specified for thickness. An alternative and a closer approximation would
B02.10 on Thermostat Metals and Electrical Resistance Heating Materials.
be that for ribbon rolled round wire, the electrical resistance would be
Current edition approved April 1, 2018. Published April 2018. Originally
calculated on a cross 6 % less than a true rectangle.
approved in 1952. Last previous edition approved in 2013 as B267 – 07 (2013).
DOI: 10.1520/B0267-07R18.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or 8. Temperature Coefficient of Resistance
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
8.1 The change in resistance with change in temperature,
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. expressed as the mean temperature coefficient of resistance
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B267 − 07 (2018)
TABLE 1 Classes of Alloys and Requirements
Mean Temperature Coefficient of Resistance, α ppm for Maximum Thermal emf
m
Elongation in 10 in., min, %
B
°C Over Temperature Range,Δ T versus Copper, mV/°C
Resistivity,
Alloy Alloy Composition,
Over 0.002 to
0.0009
Ω·cmil/ft
A
Class approximate, % D
Temperature
0.002 0.001
in. in
(µΩ·m)
ΔT α ΔT mV/°C
m C
D D
Range, ΔT in. in in. in Diameter
Diameter Diameter and Finer
1 2 3 4 5 6 7 8 9 10 11 12
1a nickel base, nonmagnetic 800 (1.330) 0, ±20 +25 to −55 0, ±20 +25 to +105 +0.003 −65 to +250 10 5 3
1b nickel base, nonmagnetic 800 (1.330) 0, ±10 +25 to −55 0, ±10 +25 to +105 +0.003 −65 to +150 10 5 3
1c nickel base, nonmagnetic 800 (1.330) 0, ±5 +25 to −55 0, ±5 +25 to +105 +0.003 −65 to +150 10 5 3
2a iron base, magnetic 800 (1.330) 0, ±20 +25 to −55 0, ±20 +25 to +105 −0.004 −65 to +200 10 5 3
2b iron base, magnetic 800 (1.330) 0, ±10 +25 to −55 0, ±10 +25 to +105 −0.004 −65 to +150 10 5 3
3a 80 nickel, 20 chromium 650 (1.081) +80, ±20 +25 to −55 +80, ±20 +25 to +105 +0.006 −65 to +250 15 5 3
3b 80 nickel, 20 chromium, 675 (1.122) +60, ±20 +25 to −55 +60, ±20 +25 to +105 +0.006 −65 to +250 15 5 3
stabilized
4 60 nickel, 16 chromium, 675 (1.122) +140, ±30 +25 to −55 +140, ±30 +25 to +105 +0.002 −65 to +200 15 5 3
balance iron
5a 55 copper, 45 nickel 300 (0.499) 0, ±20 +25 to −55 0, ±20 +25 to +105 −0.045 −65 to + 150 15 5 3
5b 55 copper, 45 nickel 300 (0.499) 0, ±40 +25 to −55 0, ±40 +25 to +105 −0.045 −65 to +150 15 5 3
E E E E
6 manganin type 290 (0.482) 0, ±15 0, ±15 −0.003 +15 to +35 15 5 3
7 77 copper, 23 nickel 180 (0.299) +180, ±30 +25 to −55 +180, ±30 +25 to +105 −0.037 −65 to +150 15 5 3
8 70 nickel, 30 iron 125 (0.199) +3600, ±400 +25 to −50 +4300, ±400 +25 to +104 −0.040 −50 to +100 15 5 3
9 90 copper, 10 nickel 90 (0.150) +450, ±50 +25 to −55 +450, ±50 +25 to +105 −0.026 −65 to +150 15 5 3
10 94 copper, 6 nickel 60 (0.100) +700, ±200 +25 to −55 +700, ±200 +25 to +105 −0.022 −65 to +150 15 5 3
11 98 copper, 2 nickel 30 (0.050) +1400, ±300 +25 to −55 +1400, ±300 +25 to +105 0.014 −65 to +150 15 5 3
A
Alloy Classes 1a to 8 inclusive are designed to provide controlled temperature coefficients. Values shown for other classes are for information only. All values are based
on a reference temperature of 25°C.
B
Alloy Classes 1a, 1b, 1c, 2a, 2b, 3a, 4, and 6 are designed to give a low emf versus copper. Values shown for other classes are for information only. Maximum indicates
the maximum deviation from zero and the plus or minus sign the polarity of the couple.
C
The maximum temperature values listed apply to the alloy wire only. Caution should be exercised pending knowledge of the maximum temperature of use for the coating
material involved.
D
If metric sizes are desired, 1 in. = 25.4 mm.
E
Alloy Class 6 (manganin type for resistors), has a temperature-resistance curve of parabolic shape with the maximum resistance normally located between 25 and 30°C.
m
Thus, Columns 5 and 7 cannot indicate 25°C as a limit but α may be expressed as a maximum of +15 ppm for 15°C to the temperature of maximum resistance and a
maximum of −15 ppm from the temperature of maximum resistance to 35°C. All of the information included in this note is based on measurements made in accordance
with Test Method B84.
A
TABLE 2 Dimensions of Enamel Coated Wire
Nominal Bare Wire Size Light Coated Wire Medium Coated Wire Heavy Coated Wire
Outside Diameter, Outside Diameter, Outside Diameter, Outside Diameter, Outside Diameter, Outside Diameter,
B&S Gage No. Diameter, in.
min, in. max, in. min, in. max, in. min, in. max, in.
28 0.0126 0.0130 0.0134 0.0134 0.0139 0.0139 0.0144
29 0.0113 0.0116 0.0120 0.0120 0.0125 0.0125 0.0130
30 0.010 0.0103 0.0107 0.0107 0.0112 0.0112 0.0116
31 0.0089 0.0092 0.0096 0.0096 0.0100 0.0100 0.0103
32 0.008 0.0083 0.0086 0.0086 0.0090 0.0090 0.0093
33 0.0071 0.0073 0.0076 0.0076 0.0080 0.0080 0.0083
34 0.0063 0.0064 0.0067 0.0067 0.0071 0.0071 0.0074
35 0.0056 0.0057 0.0060 0.0060 0.0064 0.0064 0.0067
36 0.005 0.0051 0.0054 0.0054 0.0057 0.0057 0.0060
37 0.0045 0.0046 0.0049 0.0049 0.0052 0.0052 0.0055
38 0.004 0.0041 0.0043 0.0043 0.0046 0.0046 0.0049
39 0.0035 0.0036 0.0038 0.0038 0.0041 0.0041 0.0043
40 0.0031 0.0032 0.0034 0.0034 0.0037 0.0037 0.0039
0.00275 0.0029 0.0031 0.0031 0.0033 0.0033 0.0035
0.0025 0.0026 0.0028 0.0028 0.0030 0.0030 0.0032
0.00225 0.00235 0.0025 0.0025 0.0027 0.0027 0.0029
0.002 0.0021 0.0022 0.0022 0.0024 0.0024 0.0026
0.00175 . 0.0019 0.0019 0.0021 0.0021 0.0023
0.0015 . 0.0016 0.0016 0.0018 0.0018 0.0020
0.0014 . 0.0015 0.0015 0.0017 0.0017 0.0019
0.0013 . 0.0014 0.0014 0.0016 0.0016 0.0018
0.0012 . 0.0013 0.0013 0.0015 0.0015 0.0017
0.0011 . 0.0012 0.0012 0.0014 0.0014 0.0016
0.001 . 0.0011 0.0011 0.0013 0.0013 0.0015
0.0009 . 0.0010 0.0010 0.0012 0.0012 0.0014
0.0008 . 0.0009 0.0009 0.0010 0.0010 0.0012
0.0007 . 0.0008 0.0008 0.0009 0.0009 0.0010
0.0006 . 0.0007 0.0007 0.0008 0.0008 0.0009
0.0005 . 0.0006 0.0006 0.0007 0.0007 0.0008
A
To convert from inches to millimetres multiply by 25.4.
B267 − 07 (2018)
based on the reference temperature of 25°C, shall be within the 13. Enamel Coatings
limits specified in Table 1, Columns 4 and 6, over the
13.1 Enamel coatings shall include any baked-on film of
corresponding temperature ranges specified in Columns 5 and
insulating material, such as varnish enamel, polyurethane,
7. The mean temperature coefficient of resistance referred to
vinyl acetal, etc. and shall conform to the requirements
25°C is defined as the slope of a chord of an arc. This slope is
presc
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it 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 version
of the standard as published by ASTM is to be considered the official document.
Designation: B267 − 07 (Reapproved 2013) B267 − 07 (Reapproved 2018)
Standard Specification for
Wire for Use In Wire-Wound Resistors
This standard is issued under the fixed designation B267; 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 (´) indicates an editorial change since the last revision or reapproval.
1. 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.
1.2 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.
1.3 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)(SDS) for this product/material as provided by the manufacturer, to establish appropriate safety safety, health, and
healthenvironmental practices, and determine the applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
B63 Test Method for Resistivity of Metallically Conducting Resistance and Contact Materials
B77 Test Method for Thermoelectric Power of Electrical-Resistance Alloys
B84 Test Method for Temperature-Resistance Constants of Alloy Wires for Precision Resistors
3. Significance and Use
3.1 This specification on wire and ribbon contains the generic chemistry and requirements for resistivity, temperature coefficient
of resistance, thermal emf versus copper resistance tolerances, and mechanical properties of bare wire, as well as the wire enamels
and insulations of alloys normally used in the manufacture of wound resistors.
4. Alloy Classes
4.1 Fifteen classes of alloys are covered by this specification as listed in Table 1.
5. Elongation
5.1 The wire shall conform to the requirements for elongation as prescribed in Table 1, when tested on a 10-in. (254-mm) length.
6. Resistivity
6.1 The bare wire shall conform to the requirements for nominal resistivity as prescribed in Table 1.
6.2 Actual resistivity shall not vary from nominal resistivity by more than 65 % for Alloy Classes 1 to 4 inclusive, and 610 %
for Alloy Classes 5 to 11 inclusive.
7. Nominal Electrical Resistance per Unit Length
7.1 The nominal resistance per unit length for round wire shall be calculated from the nominal resistivity and the nominal
cross-sectional area.
This specification 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 and Electrical Resistance Heating Materials.
Current edition approved May 1, 2013April 1, 2018. Published May 2013April 2018. Originally approved in 1952. Last previous edition approved in 20072013 as B267 –
07. 07 (2013). DOI: 10.1520/B0267-07R13.10.1520/B0267-07R18.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’sstandard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B267 − 07 (2018)
TABLE 1 Classes of Alloys and Requirements
Mean Temperature Coefficient of Resistance, α ppm for Maximum Thermal emf
m
Elongation in 10 in., min, %
B
°C Over Temperature Range,Δ T versus Copper, mV/°C
Resistivity,
Alloy Alloy Composition,
Over 0.002 to
0.0009
Ω·cmil/ft
A Temperature
Class approximate, % D
0.002 0.001
in. in. in
(μΩ·m)
ΔTΔT α ΔTΔT mV/°C Range, Δ
m
D D
Diameter
in. in. in in. in. in
C
TΔT
and Finer
Diameter Diameter
1 2 3 4 5 6 7 8 9 10 11 12
1a nickel base, nonmagnetic 800 (1.330) 0, ±20 +25 to −55 0, ±20 +25 to +105 +0.003 −65 to +250 10 5 3
1b nickel base, nonmagnetic 800 (1.330) 0, ±10 +25 to −55 0, ±10 +25 to +105 +0.003 −65 to +150 10 5 3
1c nickel base, nonmagnetic 800 (1.330) 0, ±5 +25 to −55 0, ±5 +25 to +105 +0.003 −65 to +150 10 5 3
2a iron base, magnetic 800 (1.330) 0, ±20 +25 to −55 0, ±20 +25 to +105 −0.004 −65 to +200 10 5 3
2b iron base, magnetic 800 (1.330) 0, ±10 +25 to −55 0, ±10 +25 to +105 −0.004 −65 to +150 10 5 3
3a 80 nickel, 20 chromium 650 (1.081) +80, ±20 +25 to −55 +80, ±20 +25 to +105 +0.006 −65 to +250 15 5 3
3b 80 nickel, 20 chromium, 675 (1.122) +60, ±20 +25 to −55 +60, ±20 +25 to +105 +0.006 −65 to +250 15 5 3
stabilized
4 60 nickel, 16 chromium, 675 (1.122) +140, ±30 +25 to −55 +140, ±30 +25 to +105 +0.002 −65 to +200 15 5 3
balance iron
5a 55 copper, 45 nickel 300 (0.499) 0, ±20 +25 to −55 0, ±20 +25 to +105 −0.045 −65 to + 150 15 5 3
5b 55 copper, 45 nickel 300 (0.499) 0, ±40 +25 to −55 0, ±40 +25 to +105 −0.045 −65 to +150 15 5 3
E E E E
6 manganin type 290 (0.482) 0, ±15 0, ±15 −0.003 +15 to +35 15 5 3
7 77 copper, 23 nickel 180 (0.299) +180, ±30 +25 to −55 +180, ±30 +25 to +105 −0.037 −65 to +150 15 5 3
8 70 nickel, 30 iron 125 (0.199) +3600, ±400 +25 to −50 +4300, ±400 +25 to +104 −0.040 −50 to +100 15 5 3
9 90 copper, 10 nickel 90 (0.150) +450, ±50 +25 to −55 +450, ±50 +25 to +105 −0.026 −65 to +150 15 5 3
10 94 copper, 6 nickel 60 (0.100) +700, ±200 +25 to −55 +700, ±200 +25 to +105 −0.022 −65 to +150 15 5 3
11 98 copper, 2 nickel 30 (0.050) +1400, ±300 +25 to −55 +1400, ±300 +25 to +105 0.014 −65 to +150 15 5 3
A
Alloy Classes 1a to 8 inclusive are designed to provide controlled temperature coefficients. Values shown for other classes are for information only. All values are based
on a reference temperature of 25°C.
B
Alloy Classes 1a, 1b, 1c, 2a, 2b, 3a, 4, and 6 are designed to give a low emf versus copper. Values shown for other classes are for information only. Maximum indicates
the maximum deviation from zero and the plus or minus sign the polarity of the couple.
C
The maximum temperature values listed apply to the alloy wire only. Caution should be exercised pending knowledge of the maximum temperature of use for the coating
material involved.
D
If metric sizes are desired, 1 in. = 25.4 mm.
E
Alloy Class 6 (manganin type for resistors), has a temperature-resistance curve of parabolic shape with the maximum resistance normally located between 25 and 30°C.
m
Thus, Columns 5 and 7 cannot indicate 25°C as a limit but α may be expressed as a maximum of + 15of +15 ppm for 15°C to the temperature of maximum resistance
and a maximum of − 15 of −15 ppm from the temperature of maximum resistance to 35°C. All of the information included in this note is based on measurements made
in accordance with Test Method B84.
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
depending on the width-to-thickness ratio and the specific manufacturing practice. The conventional formula for computing ohms per foot and feet per
pound is to consider the cross section as 17 % less than a true rectangle when width is more than 15 times the thickness and 6 % less than a true rectangle
in other cases. This is not valid in view of modern rolling equipment and practices, but still is widely used as a basis of description. Ribbon actually is
made to a specified resistance per foot, and no tolerance is specified for thickness. An alternative and a closer approximation would be that for ribbon
rolled round wire, the electrical resistance would be calculated on a cross 6 % less than a true rectangle.
8. Temperature Coefficient of Resistance
8.1 The change in resistance with change in temperature, expressed as the mean temperature coefficient of resistance based on
the reference temperature of 25°C, shall be within the limits specified in Table 1, Columns 4 and 6, over the corresponding
temperature ranges specified in Columns 5 and 7. The mean temperature coefficient of resistance referred to 25°C is defined as
the slope of a chord of an arc. This slope is determined from the following equation:
α 5 ΔR/R ΔT 310
~ !
m 25
where:
α = mean temperature coefficient of resistance, ppm/°C, Table 1, Columns 4 and 6,
m
Δ R = change in resistance over temperature range indicated in Table 1, Columns 5 and 7,
ΔR = change in resistance over temperature range indicated in Table 1, Columns 5 and 7,
R = resistance at 25°C,
ΔT = temperature range indicated in Table 1, Columns 5 and 7.
8.2 For Alloy Classes 1, 2, and 5, the temperature coefficient as specified in Table 1 of any 10-ft (3-m) length shall not vary
more than 3 ppm/°C from that of any other 10-ft length on the same spool or coil.
9. Thermal EMF with Respect to Copper
9.1 The thermal electromotive force (emf) with respect to copper shall fall within the limits shown in Table 1, in the
corresponding temperature ranges.
B267 − 07 (2018)
A
TABLE 2 Dimensions of Enamel Coated Wire
Nominal Bare Wire Size Light Coated Wire Medium Coated Wire Heavy Coated Wire
Outside Diameter, Outside Diameter, Outside Diameter, Outside Diameter, Outside Diameter, Outside Diameter,
B&S Gage No. Diameter, in.
min, in. max, in. min, in. max, in. min, in. max, in.
28 0.0126 0.0130 0.0134 0.0134 0.0139 0.0139 0.0144
29 0.0113 0.0116 0.0120 0.0120 0.0125 0.0125 0.0130
30 0.010 0.0103 0.0107 0.0107 0.0112 0.0112 0.0116
31 0.0089 0.0092 0.0096 0.0096 0.0100 0.0100 0.0103
32 0.008 0.0083 0.0086 0.0086 0.0090 0.0090 0.0093
33 0.0071 0.0073 0.0076 0.0076 0.0080 0.0080 0.0083
34 0.0063 0.0064 0.0067 0.0067 0.0071 0.0071 0.0074
35 0.0056 0.0057 0.0060 0.0060 0.0064 0.0064 0.0067
36 0.005 0.0051 0.0054 0.0054 0.0057 0.0057 0.0060
37 0.0045 0.0046 0.0049 0.0049 0.0052 0.0052 0.0055
38 0.004 0.0041 0.0043 0.0043 0.0046 0.0046 0.0049
39 0.0035 0.0036 0.0038 0.0038 0.0041 0.0041 0.0043
40 0.0031 0.0032 0.0034 0.0034 0.0037 0.0037 0.0039
0.00275 0.0029 0.0031 0.0031 0.0033 0.0033 0.0035
0.0025 0.0026 0.0028 0.0028 0.0030 0.0030 0.0032
0.00225 0.00235 0.0025 0.0025 0.0027
...