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.

ELECTRICAL RESISTANCE - Chromel 126, Chromel A, Chromel C, Chromel D
nickel/chromium based alloys

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%.