Alloy 36 (Invar®): Precision Low‑Expansion Nickel‑Iron Alloy

1.3912 (FeNi36) is a 36% nickel-iron alloy. It exhibits a near zero rate of thermal expansion from around –100°C up to 200°C. This is around a tenth of the expansion rate of carbon steels. Alloy 36 also demonstrates a high retention of strength and toughness at cryogenic temperatures, making it suitable for a variety of low temperature or low expansion applications. The alloy is ideally suited to areas where dimensional changes due to temperature must be minimal, such as tooling for aerospace composites, radio and electronic devices and structural members in precision equipment such as lasers, measuring devices, thermostats and cryogenic instrumentation. Alloy 36 can also be utilised in combination with a high expansion material to crate mechanical movement with temperature in thermomechanical controls and switchgear.

Properties

General

Property	Temperature	Value
Density	23.0 °C	8.13 g/cm³

Mechanical

Property	Temperature	Value
Elastic modulus	23.0 °C	140 GPa
Elongation	23.0 °C	30 %
Hardness, Vickers	23.0 °C	140 [-]
Tensile strength	23.0 °C	480 MPa
Yield strength	23.0 °C	310 MPa

Thermal

Property	Temperature	Value
Coefficient of thermal expansion	30.0 °C	1.2E-6 1/K
	150.0 °C	2.7E-6 1/K

Melting point		1450 °C
Specific heat capacity	23.0 °C	510 J/(kg·K)
Thermal conductivity	23.0 °C	10.5 W/(m·K)

Chemical properties

Property	Value
Iron	63 %
Manganese	0.6 %
Nickel	36 %
Silicon	0.4 %

Technological properties

Property
Application areas	General: Positioning devices, bimetal thermostats, advanced composite moulds for aerospace industry, optical devices, echo boxes and filters for mobile telephones, magnetic shielding, small electrical transformers, metrology devices, scientific instruments, electrical circuit breakers, temperature regulators, clock balance wheels, pendulum clocks, precision condenser blades, radar and microwave cavity resonators, special electronic housings, seals, spacers, and specialized frames, high voltage transmission lines

DIN 43720 Grade X10NiCr32-20 Quenched Steel – High‑Temperature Performance for Petroleum Tubes FeNi42 Alloy: Low Thermal Expansion for Precision Seals

Metal