Cupronickel strip is a copper alloy with nickel as the primary alloying element. Based on copper-nickel alloys, the addition of a third element such as zinc, manganese, or aluminum results in correspondingly named cupronickel strips: zinc cupronickel strip, manganese cupronickel strip, and aluminum cupronickel strip. Copper-nickel alloys exhibit good corrosion resistance, moderate strength, high plasticity, and can be processed under both hot and cold pressure conditions.
Common cupronickel strips mainly include four grades: B0.6, B5, B19, and B30, with B19 and B30 being the most commonly used. The American standard includes a wider range of grade series. Cupronickel strip forms a continuous solid solution of Cu and Ni with a face-centered cubic lattice. When the temperature is below 322°C, the copper-nickel phase diagram exhibits a relatively broad composition-temperature region of metastable decomposition. Adding a third element such as Fe, Cr, Sn, Ti, Co, Si, or Al to Cu-Ni alloys can alter the range and position of the metastable decomposition composition-temperature region while also improving certain properties of the alloy. Common cupronickel plates possess excellent cold and hot workability, allowing them to be easily processed into sheets, strips, tubes, rods, profiles, wires, and other forms. They exhibit good weldability, supporting soft and hard soldering, gas-shielded arc welding, and resistance welding. Their machinability is 20% that of free-cutting brass HPb63-3. Common cupronickel plates offer good corrosion resistance, moderate strength, high plasticity, and the ability to undergo cold and hot pressure processing, along with excellent electrical properties. In addition to being used as structural materials, they are also important high-resistance and thermocouple alloys.