Iron
Fe
Bal.
Nickel
Ni
35.0~37.0%
Manganese
Mn
0.2~0.6%
Silicon
Si
≤0.3%
Carbon
C
≤0.05%
Sulphur
S
≤0.02%
Phosphorus
P
≤0.02%
Invar alloy is also called INVAR alloy,it is an alloy consisting of nickel (Ni, 36%) and iron (Fe, the rest), has a uniquely low coefficient of thermal expansion. The Curie point of the alloy is about 230℃. Below this temperature, the alloy is ferromagnetic and has a very low expansion coefficient. Above this temperature, the alloy is non-magnetic, The expansion coefficient increases. The alloy is mainly used to manufacture components with approximately constant size within the range of temperature changes, and is widely used in the radio industry, precision instruments, meters and other industries.
Available shapes:
Invar wire, bar, bar, strip, forming, sheet, sheet, tube and other standard shapes are available.
Invar alloy Physical properties
Density |
Resistivity at 20℃ |
Thermal conductivity |
Elastic modulus |
Curie point |
(g/cm3) |
(Ωmm2/m) |
λ/ W/(m*℃) |
E/ Gpa |
Tc/ ℃ |
8.1 |
0.78 |
11 |
144 |
230 |
Invar alloy Coefficient of expansion
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 |
Invar alloy Mechanical performance
Tensile strength |
Elongation |
Mpa |
% |
641 |
14 |
689 |
9 |
731 |
8 |
Invar alloy Temperature Coefficient of Resistance
Temperature range ℃ |
20~50 |
20~100 |
20~200 |
20~300 |
20~400 |
aR/ 103 *℃ |
1.8 |
1.7 |
1.4 |
1.2 |
1.0 |
Product heat treatment process |
Stress relief annealing |
Heat to 530~550℃, keep warm for 1~2 h. Cool in the furnace. |
Annealing |
The workpiece is heated to 830~880℃, and kept for 30 minutes. Furnace cooling. |
Stabilization |
- Heat to 830 ℃ in protective atmosphere, keep for 20min. ~ 1h, quench.
- Temper
|
Precautions |
- The alloy cannot be hardened by heat treatment.
- Surface treatment can be sandblasted, polished and pickled.
|
Invar alloy Supply form and specification
Alloy grade |
Form |
Size |
Invar |
Wire |
D= 0.1~8mm |
Invar |
Strip |
W= 5~250mm |
T= 0.1mm |
Invar |
Foil |
W= 10~100mm |
T= 0.01~0.1mm |
Invar |
Bar |
Dia= 8~100mm |
L= 50~1000mm |