Kanthal is a world-leading brand for products and services in the area of industrial heating technology and resistance materials.

Nikrothal 40 (Resistance heating wire and resistance wire)

Datasheet updated 2012-06-20 14:35:05 (supersedes all previous editions)

Nikrothal 40 is an austenitic nickel-chromium alloy (NiCr alloy) for use at temperatures up to 1100°C (2010°F). The alloy is characterized by high resistivity and good oxidation resistace. It has good ductility after use and excellent weldability.

Typical applications for Nikrothal 40 are night-storage heaters, convection heaters, heavy duty rheostats and fan heaters. The alloy is also used for heating cables and rope heaters in defrosting and de-icing elements, electric blankets and pads, car seats, baseboard heaters and floor heaters, resistors.

Chemical composition

C % Si % Mn % Cr % Ni % Fe %
Nominal composition Bal.
Min - 1.6 - 18.0 34.0
Max 0.10 2.5 1.0 21.0 37.0

Mechanical properties

Wire size Yield strength Tensile strength Elongation Hardness
Ø Rp0.2 Rm A
mm MPa MPa % Hv
1.0 340 675 35 180
4.0 300 650 30 160
Mechanical properties at elevated temperature
Temperature °C 800 900 1000
MPa 170 95 58

Ultimate tensile strength - deformation rate 5.0 x 10-2/min

Creep strength - 1% elongation in 1000 h
Temperature °C 800 1000
MPa 20 4

Physical properties

Density g/cm3 7.90
Electrical resistivity at 20°C Ω mm2/m 1.04

Temperature factor of resistivity
Temperature°C 100 200 300 400 500 600 700 800 900 1000 1100
Ct 1.03 1.06 1.10 1.12 1.15 1.17 1.19 1.21 1.22 1.23 1.24

Coefficient of thermal expansion
Temperature °C Thermal Expansion x 10-6/K
20 - 250 16
20 - 500 17
20 - 750 18
20 - 1000 19

Thermal conductivity
Temperature °C 20 100 200 300 400 500 600 700 800 900 1000 1100
W m-1 K-1 13 14 15 16 18 19 21 22 24 25 26 28

Specific heat capacity
Temperature °C 20 100 200 300 400 500 600 700 800 900 1000 1100
kJ kg-1 K-1 0.50 0.50 0.50 0.51 0.54 0.57 0.60 0.62 0.64 0.67 0.70 0.73

Melting point °C 1390
Max continuous operating temperature in air °C 1100
Magnetic properties The material is non-magnetic
Emissivity - fully oxidized material 0.88

Disclaimer: Recommendations are for guidance only, and the suitability of a material for a specific application can be confirmed only when we know the actual service conditions. Continuous development may necessitate changes in technical data without notice. This datasheet is only valid for Kanthal materials.

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