Nimonic is a nickel based superalloy with low creep at high temperature characteristics. It comprises at least 60% Nickel and at least 20 % Chromium. Depending on the grade, it also includes Cobalt and Titanium.
Nimonic is mainly used for its resistance to very high temperatures although it has also good corrosion resistance.
To be able to have the spring quality, the finished parts must be hardened by a heat treatment between 600 and 750 ° during 16 hours, depending on the grades of Nimonic.
Nimonic is used for gas turbines, engine exhaust valves, heat exchangers, parts in glass furnaces, …
The most common Nimonic grade is Nimonic 90. This grade has about 70% Nickel, is less rich in Chromium (20%) but has a high proportion of Cobalt (15 to 20 %), which excludes it for nuclear applications. Nimonic 90 has a high tensile strnegth and good creep resistance at temperature up to 920 °.
The other grades used are :
- Nimonic 75 (Ni80Cr20Ti) which has good resistance to corrosion at high temperatures.
- Nimonic 80, which besides the qualities of resistance to temperature up to 815°, has good weldability characteristics.
Filame mainly manufactures spring parts in Nimonic 90 (wire or sheet). These parts undergo a heat treatment to have spring quality.