Alumel

Alumel is a nickel-based alloy used primarily for thermocouple leads. It is a trade name for an alloy whose principal constituents are nickel along with aluminum and manganese, with small amounts of other elements such as silicon. In Type K thermocouples, Alumel is paired with Chromel, a nickel-chromium alloy, to form one of the most widely used temperature-sensing assemblies in industry.

In practical use, Alumel provides good oxidation resistance and ductility at elevated temperatures, allowing it to be drawn into thin wires for thermocouple leads. When combined with Chromel, the pair generates a predictable thermoelectric voltage over a broad temperature range, facilitating temperature measurement in process control, laboratory work, and aerospace applications. Lead wires made from Alumel are typically insulated and sometimes sheathed to withstand harsh environments and mechanical wear.

Compositions of commercial Alumel grades vary by supplier but share the core characteristic of being nickel-based with aluminum and manganese as major alloying elements. Trace elements and manufacturing tolerances are adjusted to meet specific sensor performance requirements. The term Alumel remains widely used in thermocouple catalogs and standards to denote the nickel-aluminum-manganese lead alloy used with Chromel in Type K thermocouples.

Overall, Alumel’s role as the counterpart to Chromel in Type K thermocouples makes it one of the most common materials in industrial temperature sensing, valued for its broad operating range, stable electrical characteristics, and compatibility with standard thermocouple practices.