Invar 42(Fe-Ni)

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1. Introduce

– Ni-Fe alloy with 42% Ni content

– Low thermal expansion alloy with a low and consistent coefficient of thermal expansion, approximately one-tenth that of carbon steel, in the range of -20 to 300°C
→ Invar 42 Coefficient of Thermal Expansion (CTE) : close to zero
→ Has a coefficient of thermal expansion consistent with glass compounds and ceramic materials
→ Used for glass-to-metal or ceramic-to-metal bonding applications

– Invar 42 has a coefficient of thermal expansion of approximately 1.1 × 10^-6 /°C, lower than Invar (1.2 × 10^-6 /°C) and most other materials

– UNS K94100

* 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

– Good dimensional stability, corrosion and oxidation resistance, strength, ductility, fatigue resistance, stress relaxation resistance

[Invar 42 Chemical Composition (%)]

C	Mn	P	S	Si
Max. 0.05	Max. 0.80	Max. 0.025	Max. 0.025	Max. 0.30

Cr	Ni	Al	Fe
Max. 0.25	41.0	Max. 0.10	Bal.

[Invar 42 Mechanical Properties]

Tensile Strength (Mpa)	Yield Strength (Mpa)	Elongation (%)
490	250	42

[Invar 42 Physical Properties]

Density (g/㎤)	Melting Range (℃)	Specific Heat (0-100℃), J/kg*℃	Coefficient of Thermal Expansion (10¯⁶/℃)
8.12	1435	500	1.1

3. Standard & Specification

– Specification : UNS K94100

Product Form	ASTM
Bar, Rod	F30
Tube, Pipe	F30, F1684
Sheet, Strip, Plate	F30, A162, B127, B582, B575, B168, B443, B463, B626, B536
Wire	F29, F30

4. Available Form

– Bar, Rod

– Plate, Sheet, Strip

– Wire, Coil

– Forgings

5. Application & Product

– Electronics, Aerospace, Electrical

Application	Product
Electronics	Electron tubes, Transformer and Capacitor bushings, Semiconductor lead frames, CRT electron guns, Microelectronics, Thermostat rods, Electronic coverings, HVT lines
Aerospace	Tooling for aerospace composites
Electrical	Bimetal thermostats, Electrical transformers, Precision condenser units