Alumel - 2.4122 - Nisil® wire

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Composition of alumel

This is a thermoelectrode alloy, most of which is nickel up to 96%. Alloy also contains 1% Co — to maintain necessary thermo-emf. Aluminum in alloy is not more than 2.5%, manganese (Mn) is also present — up to 2.2% and silicon (Si) — up to 1.2%. Doping with zirconium (0.06% Zr) and boron (0.03% B) is possible — this is one of new alloys.

Advantages

Density of alloy is 8.48 g / cm³, melting point is 1440 ° C, electrical resistivity is 0.32 Ohm • mm2 / m, coefficient of linear thermal expansion is 13.7 • 10−6 / ° C, annealing temperature is 900- 950 ° C. Physical properties of alumel are determined by nickel, which forms basis of alloy. Among main advantages are heat resistance, resistance to aggressive environments. Alloying elements enhance these qualities. Alloying increases ductility at t° 600 ° C — 1100 °C, provides long-term strength from 700 °C to 900 °C, allows use of alumel (with a stable thermo-emf value) up to 1300 °C.

Disadvantages

Nickel-based alumel wire is quite expensive since nickel is expensive metal. Its main drawback is its susceptibility to destructive action of sulfur with increasing temperature, which leads to corrosion and embrittlement. This can be corrected by increasing percentage of silicon and reducing proportion of aluminum. This replacement increases the life of thermocouple at temperatures above 1000 ° C.

Application

Alumel is widely used in pyrometry in form of tape or wire Ø 0.2 — 3.2 mm for production of temperature controllers, thermocouples, compensation wires. A thermocouple is formed by 2 dissimilar conductors soldered by ends and capable of generating thermo-EMF with increasing temperature. One of electrodes is positive, second is negative. Alumel is used in chromel-alumel thermocouple as a negative electrode for measuring t° up to 1000 °C. Thanks to alloying, this thermocouple is able to withstand short-term effects and higher temperatures up to 1300 °C even when operating in aggressive environments. Compensation wires made of alumel serve to connect thermocouples to transducers and directly to measuring instruments themselves to reduce error of readings. Due to their miniature size and high precision, chromel-aluminum sensors are widely used in aerospace engineering, automotive and other areas of modern industry.

Supplies

Alumel NMTSak 2−2-1 is supplied in the following forms:

• Wire (Ø 0.10 — 12.00 mm);
• Circle (Ø 12.0 mm — 100.0 mm);
• Tape (thickness 0.1−5.0 mm, width 3−600 mm).

Physical properties of alumel alloy NMtsAK2−2-1 at 20 °C

Buy at best price

Elektrovek-steel LLC has a wide range of thermocouples in stock. Our representative offices are located in Russia and Ukraine. You can make purchase without leaving your office through Company’s website. To purchase, you only need to place order and click «buy» button. If necessary, our managers can advise you on any current issues. They will provide all necessary information regarding product, price range, conditions of sale. Lead times are short. For bulk purchases discounts.

Alumel NMtsAK2−2-1 alloy characteristic