ASTM B267-90(1995)e1

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
• Technical Committee: B02 - Nonferrous Metals and Alloys
• Drafting Committee: B02.10 - Thermostat Metals and Electrical Resistance Heating Materials

Relations

• Replaced By: ASTM B267-90(2001) - Standard Specification for Wire for Use In Wire-Wound Resistors
• Effective Date: 01-Jan-2001

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NOTICE: This standard has either been superseded and replaced by a new version or
withdrawn.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.
e1
Designation: B 267 – 90 (Reapproved 1995) An American National Standard
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Specification for
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. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
e NOTE—Section 18 was added editorially in June 1995.
1. Scope 610 % for Alloy Classes 5 to 11 inclusive.
1.1 This specification covers round wire and ribbon with
7. Nominal Electrical Resistance per Unit Length
controlled electrical properties for use in wire-wound resis-
7.1 The nominal resistance per unit length for round wire
tance units and similar applications, but not for use as electrical
shall be calculated from the nominal resistivity and the nominal
heating elements.
cross-sectional area.
2. Referenced Documents
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
2.1 ASTM Standards:
depending on the width-to-thickness ratio and the specific manufacturing
B 63 Test Method for Resistivity of Metallically Conduct-
practice. The conventional formula for computing ohms per foot and feet
ing Resistance and Contact Materials
per pound is to consider the cross section as 17 % less than a true rectangle
B 77 Test Method for Thermoelectric Power of Electrical-
when width is more than 15 times the thickness and 6 % less than a true
Resistance Alloys
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.
B 84 Test Method for Temperature-Resistance Constants of
Ribbon actually is made to a specified resistance per foot, and no tolerance
Alloy Wires for Precision Resistors
is specified for thickness. An alternative and a closer approximation would
be that for ribbon rolled round wire, the electrical resistance would be
3. Significance and Use
calculated on a cross 6 % less than a true rectangle.
3.1 This specification on wire and ribbon contains the
8. Temperature Coefficient of Resistance
generic chemistry and requirements for resistivity, temperature
coefficient of resistance, thermal emf versus copper resistance
8.1 The change in resistance with change in temperature,
tolerances, and mechanical properties of bare wire, as well as
expressed as the mean temperature coefficient of resistance
the wire enamels and insulations of alloys normally used in the
based on the reference temperature of 25°C, shall be within the
manufacture of wound resistors.
limits specified in Table 1, Columns 4 and 6, over the
corresponding temperature ranges specified in Columns 5 and
4. Alloy Classes
7. The mean temperature coefficient of resistance referred to
4.1 Fifteen classes of alloys are covered by this specification
25°C is defined as the slope of a chord of an arc. This slope is
as listed in Table 1.
determined from the following equation:
5. Elongation
a 5 DR/R DT 3 10
~ !
m 25
5.1 The wire shall conform to the requirements for elonga-
tion as prescribed in Table 1, when tested on a 10-in. (254-mm) where:
length. a = mean temperature coefficient of resistance, ppm/°C,
m
Table 1, Columns 4 and 6,
6. Resistivity
DR = change in resistance over temperature range
6.1 The bare wire shall conform to the requirements for
indicated in Table 1, Columns 5 and 7,
nominal resistivity as prescribed in Table 1. R = resistance at 25°C,
DT = temperature range indicated in Table 1, Columns 5
6.2 Actual resistivity shall not vary from nominal resistivity
and 7.
by more than 65 % for Alloy Classes 1 to 4 inclusive, and
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
This specification is under the jurisdiction of ASTM Committee B-4 on more than 3 ppm/°C from that of any other 10-ft length on the
Metallic Materials for Thermostats, Electrical Resistance, Heating and Contacts and
same spool or coil.
is the direct responsibility of Subcommittee B04.01 on Electrical Heating and
Resistance.
9. Thermal EMF with Respect to Copper
Current edition approved May 25, 1990. Published July 1990. Originally
9.1 The thermal electromotive force (emf) with respect to
published as B 267 – 52 T. Last previous edition B 267 – 83.
Annual Book of ASTM Standards, Vol 03.04. copper shall fall within the limits shown in Table 1, in the
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) 0, 620 +25 to−55 0, 620 + 25 to + 105 + 0.003 −65 to + 250 10 5 3
1b nickel base, nonmagnetic 800 (1.330) 0, 610 +25 to−55 0, 610 + 25 to + 105 + 0.003 −65 to + 150 10 5 3
1c nickel base, nonmagnetic 800 (1.330) 0, 65 + 25 to − 55 0, 65 + 25 to + 105 + 0.003 −65 to + 150 10 5 3
2a iron base, magnetic 800 (1.330) 0, 620 +25 to−55 0,6 20 + 25 to + 105 −0.004 −65 to + 200 10 5 3
2b iron base, magnetic 800 (1.330) 0, 610 +25 to−55 0, 610 + 25 to + 105 −0.004 −65 to + 150 10 5 3
3a 80 nickel, 20 chromium 650 (1.081) + 80, 620 +25 to−55 +80, 620 + 25 to + 105 + 0.006 −65 to + 250 15 5 3
3b 80 nickel, 20 chromium, 675 (1.122) + 60,6 20 +25 to−55 +60, 620 + 25 to + 105 + 0.006 −65 to + 250 15 5 3
stabilized
4 60 nickel, 16 chromium, 675 (1.122) + 140, 630 + 25 to − 55 + 140, 630 + 25 to + 105 + 0.002 −65 to + 200 15 5 3
balance iron
5a 55 copper, 45 nickel 300 (0.499) 0, 620 +25 to−55 0, 620 + 25 to + 105 −0.045 −65 to + 150 15 5 3
5b 55 copper, 45 nickel 300 (0.499) 0, 640 +25 to−55 0, 640 + 25 to + 105 −0.045 −65 to + 150 15 5 3
EE EE
6 manganin type 290 (0.482) 0, 615 0, 615 −0.003 + 15 to + 35 15 5 3
7 77 copper, 23 nickel 180 (0.299) + 180, 630 + 25 to − 55 + 180,6 30 + 25 to + 105 −0.037 −65 to + 150 15 5 3
8 70 nickel, 30 iron 125 (0.199) + 3600, 6400 + 25 to − 50 + 4300, 6400 + 25 to + 104 −0.040 −50 to + 100 15 5 3
9 90 copper, 10 nickel 90 (0.150) + 450, 650 + 25 to − 55 + 450, 650 + 25 to + 105 −0.026 −65 to + 150 15 5 3
10 94 copper, 6 nickel 60 (0.100) + 700, 6200 + 25 to − 55 + 700,6 200 + 25 to + 105 −0.022 −65 to + 150 15 5 3
11 98 copper, 2 nickel 30 (0.050) + 1400, 6300 + 25 to − 55 + 1400, 6300 + 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
m
30°C. Thus, Columns 5 and 7 cannot indicate 25°C as a limit but a may be expressed as a maximum of + 15 ppm for !5°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 B 84.
corresponding temperature ranges. 12. Finish
12.1 The wire shall be as uniform and free from kinks, curls,
10. Permissible Variations in Electrical Resistance
and surface defects such as seams, laminations, scale, and other
10.1 The actual resistance per unit length of any wire
irregularities as the best commercial practice will permit.
furnished under these specifications shall not vary from the
nominal resistance by more than the following amounts:
13. Enamel Coatings
Form Permissible
13.1 Enamel coatings shall include any baked-on film of
Variation, 6%
insulating material, such as varnish enamel, polyurethane,
Over 0.005 in. (0.127 mm) in diameter 5
vinyl acetal, etc. and shall conform to the requirements
0.002 to 0.005 in. (0.051 to 0.127 mm) in diameter, incl 8
Under 0.002 in (0.051 mm) in diameter 10
prescribed in 13.2 to 13.7.
Ribbon 5
13.2 The physical dimensions of the enamel film shall
10.2 For Alloy Classes 1 to 4 inclusive, the actual resistance conform to the requirements specified in Table 2.
13.3 The continuity of dielectric strength of medium or
of any 1-ft length of wire in one spool or coil shall not vary by
more than 3 % from the actual resistance of any other 1 ft of heavy enamel shall show a maximum of 10 breaks/100 ft when
tested with a potential of 150 V applied between a single
wire in the same spool or coil.
10.3 For Alloy Classes 5 to 11 inclusive, the actual mercury cup and the bared end of the wire. In the dielectric
strength test, 100 ft of the wire shall be drawn through the
resistance of any 1-ft length of wire in one spool or coil shall
not vary by more than 5 % from the actual resistance of any mercury or equivalent at a speed that will permit the recording
of 600 counts/min. The test circuit shall have a recording
ot
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