Chromel®-A2017-02-08T20:04:55+00:00

Chromel® A

80-20 Nickel-Chromium Electrical Resistance Wire

Chromel A is an alloy used at operating temperatures up to 2150 °F (1200°C). Its 80% Ni/20% Cr chemical composition gives good oxidation resistance. Its low temperature coefficient of resistance ensures fast heat up times and stable operating temperatures over its entire range of use.

Approximate Chemical Composition

Ni  78.5%
Cr  20%
Si  1%

Technical Specifications

Properties

Property Ch-A Ch-C Ch-D
Density
g/cm³ 8.41 8.25 7.94
#/in³ .3039 .2979 .2870
Electrical Resistivity, 20°C
µΩ·cm 650 675 625
Ω·circ.mil/ft 108 112 104
Ω·sq.mil/ft 510 530 490
Coefficient of Thermal Expansion
 20°C – 100°C, m/m/°C x 10-⁶ 12 13 14
 68°F – 212°F, in./in./°F x 10-⁶  6.7 7.2 7.8
 Max Operating Temp. (element)
°C 1230 1065 1040
°F 2250 1950 1900
 Melting Point (approximate)
°C 1400 1390 1390
°F 2250 2535 2535
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Nominal Percent Change in Resistance with Temperature

Temperature
°F 200 400 600 800 1000 1200 1400 1600 1800 2000
°C 93 204 315 427 538 649 760 871 982 1093
Ch-A* 0.8 2.0 3.3 4.8 6.3 5.8 5.1 5.2 5.6 6.0
Ch-A** 0.43 0.93 1.46 1.94 1.90 1.04 0.71 0.79 1.18 1.66
CH-C 0.78 2.32 3.67 5.03 5.77 6.15 6.70 7.35 8.00 8.66
Ch-D 2.6 6.5 10.0 13.0 15.6 17.8 19.6 21.4 22.5 23.5

*Large diameter wire or small wire held above 250°C for extended time. This data should be used for heating element design purposes.

**Small diameter wire; rapidly cooled after annealing. Larger sizes may exhibit resistivity gains of up to 6%.