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 |
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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
