Inserts made from Nimonic 90 are used in high temperature environments where pressure and heat are extreme. It is a nickel-chromium-cobalt alloy that is precipitation hardenable and having high stress-rupture strength at elevated temperatures. Nimonic 90 is an ideal material for applications in aircraft parts and gas turbine components, such as jet engine exhaust nozzles. Typically free running inserts are used in environments with temperatures up to 1200° F and locking inserts up to 900° F. The chemical composition of Nimonic 90 is Ni 54%, Cr 18-21%, Co 15-21%, Ti 2-3%, and Al 1-2%. The material is covered by British Standard BS HR 503.