Haynes 25

Haynes 25 is a cobalt-based alloy, which combines good formability and excellent high-temperature properties. The alloy is resistant to oxidation and carburization to 1900°F.

Haynes 25 has given good service in many jet engine parts. Some of these include turbine blades, combustion chambers, afterburner parts, and turbine rings.  Haynes 25 has shown excellent resistance to the hot corrosive atmospheres such as jet engine operations. Resistance to oxidation is good for intermittent service up to 1600°F and continuous service up to 2000°F. Haynes 25 is highly resistant to scaling and oxidation at elevated temperatures, with good qualities under extreme oxidizing conditions. This material also possesses excellent resistance to chemical oxidizing agents, and extraordinary resistance to hydrochloric and nitric acids at certain concentrations and temperatures. Resistance to salt spray corrosion is very good.

For optimum properties, most wrought products are shipped in the solution heat-treated condition. This alloy is normally solution heat treated in the temperature range of 2150 to 2250°F, and then either rapid air-cooled or water-quenched. Sheet 0.025" thick or less is solution heat treated at 2150°F, rapid air cooled or water quenched.; over 0.026" and over, at 2200°F, rapid air cooled or water quenched; plate at 2200°F, water quenched; and bar at 2250°F, water quenched.

Room and Elevated Temperature Properties Enhanced by Cold Work and Aging Cold working and aging, when properly employed, improves both the room and elevated temperature tensile strength of Haynes 25 sheet. Moderate amounts of cold work will increase creep strength up to 1800°F and stress rupture strength at temperatures up to 1500°F. Aging produces no significant benefit. Strain aging, at 700 to 1100°F, however, improves creep and rupture strength below 1300°F.