
OhmAlloy-4J36 (Expansion alloy)
(Common Name: Invar, FeNi36, Invar Standard, Vacodil36)
OhmAlloy-4J36 (Invar), also known generically as FeNi36 (64FeNi in the US), is a nickel–iron alloy notable for its uniquely low coefficient of thermal expansion (CTE or α).
OhmAlloy-4J36 (Invar) is used where high dimensional stability is required, such as precision instruments, clocks, seismic creep gauges, television shadow-mask frames, valves in motors, and antimagnetic watches. In land surveying, when first-order (high-precision) elevation leveling is to be performed, the Level staff (leveling rod) used is made of Invar, instead of wood, fiberglass, or other metals. Invar struts were used in some pistons to limit their thermal expansion inside their cylinders.
Normal 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 |
Typical Physical properties
Density (g/cm3) | 8.1 |
Electrical resistivity at 20℃(Ωmm2/m) | 0.78 |
Temperature factor of resistivity(20℃~200℃)X10-6/℃ | 3.7~3.9 |
Thermal conductivity, λ/ W/(m*℃) | 11 |
Curie point Tc/ ℃ | 230 |
Elastic Modulus, E/ Gpa | 144 |
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 |
Typical Mechanical properties
Tensile Strength | Elongation |
Mpa | % |
641 | 14 |
689 | 9 |
731 | 8 |
Temperature factor of resistivity
Temperature range, ℃ | 20~50 | 20~100 | 20~200 | 20~300 | 20~400 |
aR/ 103 *℃ | 1.8 | 1.7 | 1.4 | 1.2 | 1.0 |
The heat treatment process | |
Annealing for stress relief | Heated to 530~550℃ and hold 1~2 h. Cold down |
annealing | In order to eliminate hardening, which be bring out in cold-rolled, cold drawing process. Annealing needs heated to 830~880℃ in vacuum,hold 30 min. |
The stabilization process |
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Precautions |
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Sales Manager:Michaeal Qiu.
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Ohmalloy Material Co.,Ltd
Ohmalloy Material Co.,Ltd is a high-tech enterprise which specialized in making all kinds of alloy such as high resistance alloy, low-resistance copper nickel alloy, precision alloy, FeCrAl alloy and thermocouple Alloy.
Ohmalloy Material Co.,Ltd have a full production line from melting, surface cleaning, rolling and slitting, full set of testing machine and can meet all kinds of technical requirement from customer. Our product is widely used in heating equipment, big steel mill, mineral, electrical equipment, food machinery, auto industry, aerospace industry. Our product not only is popular in domestic market, but also been exported to all over the world.
Our company aims to be the best-quality alloy producer in the
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