Invar 36

 Invar 36 is a Nickel-Iron, low expansion alloy containing 36% Nickel, belongs to one of the controlled expansion alloys with the lowest thermal expansion coefficient of any of the iron-nickel alloys. It is widely used in the electronics industry such as radios, thermostats, glass-to-metal seals and structural components in laser systems.Chemical Compositions: 

CMnSPSiCrNiFeMax 0.10Max 0.50Max 0.004Max0.006Max 0.35Max 0.25Nom 36.0Balance

Physical Properties: 

Specific gravity ................ 8.08
Density
lb/cu in ......................... 0.291
kg/cu m ......................... 8055
Thermal conductivity
Btu-in/ft²/hr/°F ................ 72.6
W/m þ K .......................... 10.5Electrical resistivity
ohm-cir mil/ft ................... 495
microhm-mm ...................... 820
Temperature coefficient of electrical
resistivity
per °F (70/212°F) ............. 0.0006
per °C (21/100°C) ............. 0.0011

Coefficient of Thermal Expansion: 

TemperatureRangeCoefficient of Thermal Expansion℃℉10-6/℃10-6/℉20~100
20~150
20~200
20~250
20~300
20~350 68~212
 68~302
 68~392
 68~482
 68~572
 68~6621.5
2.0
2.6
3.5
5.5
7.20.8
1.1
1.4
1.9
3.1
4.0

Mechanical Properties in the Annealed Condition: 

HardnessTensile StrengthYield StrengthElongationModulus of Elasticity125 HV447 Nmm-2278 Nmm-2<45%140 - 150 GPa