Constantan - 2.0842 wire
International Equivalent
| Mark | Analogue | W. Nr. | Aisi Uns | En | Order |
|---|---|---|---|---|---|
| MNMts43-1.5 | 2.0842 | C72150 | CuNi44 | Delivery from the stock, in stock |
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Composition
The name constantan (constans) translates from Latin as "constant", "unchanging", because its electrical resistance is unchanged with temperature variations. This silvery yellow alloy, contains 32-40% Ni, up to 60% Cu and up to 2% Mn. The melting point is 1260 °C. Specific gravity 8.9 g/cm³, TKR = 14 - 10-6/°C.
Advantages .
At 20 °C specific electrical resistance = 0.48 Ohm-mm2/m. After the stabilizing annealing the temperature coefficient of linear expansion reaches 2x10-61/K, the annealed alloy has ðp = 400- 500 MPa, ер = 40 - 50%, r = 0,46 - 0,48 Ohm-mm2/m; for the hard - sr = 655 - 720 MPa, ер = 2...5%, r = 0,46 - 0,52 Ohm-mm2/m.
Disadvantages
A significant drawback - a significant thermal EMF (40-50 μV / ° C) in a pair with copper, which limits its use in stable resistors and high-precision devices - because heating the contact terminals leads to the appearance of currents that distort readings. Therefore, if high accuracy is required, manganine is used instead of constantan.
Applications
Constantan is widely used in the manufacture of compensation wires, rheostats, heating devices. It is used for wire Ø 0,03-5 mm and tape up to 0,1 mm thickness. Significant thermal EMF of constantan in contact with copper led to its use in thermocouples for measurements of relatively low t° up to 500 °C. For this purpose thermocouples are usually used, where positive thermoelectrodes are iron, copper and chromel, and negative ones - constantan, alumel and copel.
Chemical composition of constantan MNMz 43-1.5 in % material
| Ni+Co | Fe | C | Si | Mn | Cu | Impurities |
|---|---|---|---|---|---|---|
| 39 - 41 | ≤ 0.5 | ≤ 0.1 | ≤ 0.1 | 1 - 2 | 56.1 - 60 | total 0.9 |
Supplies
Most of all, constantan is in demand in pyrometry, so the main type of rolled product is wire. Its price depends on the world prices of copper and nickel, the main constituents of constantan.
The alloy comes in the following forms:
- Ribbon (thickness 0.1-5.0 mm, width 3-600mm).
- Circle (Ø 12 mm - 100 mm);
- Wire (Ø 0.1 - 12 mm);
Physical properties of constantan alloy MNMts 43-1.5 at 20 °C
| Hardness, soft alloy HB 10 -1 | Hardness, alloy hard HB 10 -1 | Melting temperature, °C: | Hot work temperature, °C: | Annealing temperature, °C: |
|---|---|---|---|---|
| 380-480 MPa | 620-720 MPa | 1350 | 1170 - 920 | 870 - 950 |
