Invar Alloy

: http://alloy-material.com/3-1-2-invar-alloy.html

Introduction:
The curie point of Invar alloy is about 230℃. When the temperature is lower than 230, the alloy is ferromagnetic with a very low expansion coefficient. Otherwise, the alloy is non-magnetic and the expansion coefficient increases. This Invar alloy is mainly used for manufacturing component with nearly constant size in the range of temperature variety. And it is widely used in radio industry, precision instrument, meter and other industries.

Supply of Invar alloy

Style	Size
Wire	D=0.1~8mm
Strip	W= 5~250mm	T= 0.1mm
Foil	W= 10~100mm	T= 0.01~0.1mm
Rod	Dia=8~100mm	L=50~1000mm

Chemical composition (%)

Ni	35~37.0	Fe	Bal.	Co	-	Si	≤0.3
Mo	-	Cu	-	Cr	-	Mn	0.2~0.6
C	≤0.05	P	≤0.02	S	≤0.02

Physical property

Density (g/cm³)	8.1
Resistivity under 20℃(Ωmm²/m)	0.78
Thermal conductivity, λ/ W/(m*℃)	11
Curie point, Tc/ ℃	230
Elasticity modulus, E/ Gpa	144

Expansion coefficient

θ/℃	α1/10-6℃-1	θ/℃	α1/10-6℃-1
20~-60	1.8	20~250	3.6
20~-40	1.8	20~300	5.2
20~-20	1.6	20~350	6.5
20~-0	1.6	20~400	7.8
20~50	1.1	20~450	8.9
20~100	1.4	20~500	9.7
20~150	1.9	20~550	10.4
20~200	2.5	20~600	11.0

Mechanical property

Tensile Strength (Mpa)	Elongation (%)
641	14
689	9
731	8

Resistance temperature coefficient

Temperature range, ℃	20~50	20~100	20~200	20~300	20~400
aR/ 103*℃	1.8	1.7	1.4	1.2	1.0

Heat treatment process

Stress-relief annealing	Be heated to 530~550℃ and keep warm for 1-2h. furnace cooling.
Anneal	The workpiece is heated to 830~880℃ and be kept for 30 min. Furnace cooling.
Stabilizing treatment	1) it is heated to 830 ℃ in protective gas environment for 20min. Then conduct quenching for 1h. 2) annealing
Note	1) Alloy can not be hardened by heat treatment. 2) surface treatment can adopt sand blasting, polishing and pickling.

Index
nickel alloy, alloy pipe