Invar 36(Fe-Ni)

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1. Introduce

– Ni-Fe alloy with 36% Ni content

– Low thermal expansion alloy with a thermal expansion rate of about 1/10 of that of carbon steel in the temperature range of about -250~200℃
→ Invar36 Coefficient of Thermal Expansion (CTE) : Close to zero

– Common name : Invar 36, FeNi36

– UNS K93600 or K93603

* Invar

(1) Meaning : Little change in expansion or contraction with temperature change, so called invariant steel

(2) Features : Excellent corrosion resistance, extremely low coefficient of expansion, little dimensional change with temperature

(3) Types : Invar36, Invar 42, Invar 48, etc.

	Invar 36	Invar 42	Invar 48
Ni Composition (%)	36	42	48
Characteristics	Low expansion : little dimensional change at room temperature high strength and toughness : excellent strength and toughness at sub-zero and low temperatures	Low coefficient of expansion : low coefficient of expansion in the temperature range of 20~300℃ Stability : stable performance over a wide temperature range	Excellent magnetic shielding properties, dimensional stability, and heat resistance
Application	Precision machinery, Standard equipment, Temperature sensitive and Precise measurement	precision machinery, standard equipment, temperature sensitive applications, applications requiring higher temperature performance than Invar 36	Sensitive electronics, precision instruments, and electrical equipment

* UNS

Abbreviation for the Unified Numbering System for Metals and Alloys
Unified unique numbering system for metals and alloys
A representative number compatible with metals and alloys defined in several material-related codes, including ASTM, AISI, ASME, AWS, etc.

* K : Miscellaneous steels and Ferrous alloys

2. Property

– Cryogenic strength and toughness, corrosion resistance, good corrosion resistance

[Invar 36 Chemical Composition (%)]

C	Mn	P	S
0.60	0.40	0.025	0.25

Si	Cr	Ni	Fe
0.025	0.50	36.0	Bal.

[Invar 36 Mechanical Properties]

Tensile Strength (Mpa)	Yield Strength (Mpa)	Elongation (%)
490	240	42

[Invar 36 Physical Properties]

Density (g/㎤)	Melting Range (℃)	Specific Heat (0-100℃), J/kg*℃	Coefficient of Thermal Expansion (10¯⁶/℃)
8.1	1430	515	<1.8

3. Standard & Specification

– Specification : UNS K93600 or K93603

ASTM

B753, F1684

Product Form	ASTM	DIN
Bar, Rod	F1684, B753	17745
Wire, Coil	F1684, B603	17470
Sheet, Plate	B388, B753	17745
Strip	B603	17470

4. Available Form

– Bar, Rod

– Plate, Sheet

– Strip

– Wire, Coil

– Tube, Pipe

5. Application & Product

– Medical, Electrical, Electronic, Chemical, Optical, Nuclear weapons

Application	Product
Medical	Thermostat, Measuring equipment, Laser components, MRI
Electrical	Power supplies
Electronic	Satellite and Missile electronic control unit frames, Semiconductor lead frames, Microwave materials for devices, Substrate materials for multilayer ceramic capacitors
Chemical	Liquid oxygen and Liquid nitrogen storage containers, Piping, Bimetal, Bimetal thermostats
Optical	Mirrors, Lenses
Nuclear weapons	Fuel cladding, Control rod drive devices

(1) Thermostats / (2) Power supplies / (3) Semiconductor lead frames / (4) Liquid oxygen and liquid nitrogen storage containers / (5) Bimetals / (6) Fuel cladding materials