Excellent High-Temperature Strength, Low Thermal Expansion Characteristics, and Good Oxidation Resistance

HAYNES 242 is an age-hardenable nickel-molybdenum chromium alloy which derives its strength from a long-range ordering reaction upon aging. It has tensile and creep strength properties up to 1300°F (705°C) which are as much as double those for solid solution strengthened alloys, but with high ductility in the aged condition.
The thermal expansion characteristics of 242® alloy are much lower than those for most other alloys, and it has very good oxidation resistance up to 1500°F (815°C). Other attractive features include excellent low cycle fatigue properties, very good thermal stability, and resistance to high-temperature fluorine and fluoride environments.

Chemical composition

Applications
HAYNES 242 combines properties which make it ideally suited for a variety of component
applications in the aerospace industry. It will be used for seal rings, containment rings, duct segments, casings, fasteners, rocket nozzles, pumps, and many others. In the chemical process industry, Haynes 242 will find use in high-temperature hydrofluoric acid vapor-containing processes as a consequence of its excellent resistance to that environment. The alloy also displays excellent resistance to high-temperature fluoride salt mixtures. The high strength and fluorine environment-resistance of Haynes 242 has also been shown to provide for excellent service in fluoroelastomer process equipment, such as extrusion screws.

HAYNES 242 alloy derives its age-hardened strength from a unique long-range-ordering reaction which essentially doubles the un-aged strength while preserving excellent ductility. The ordered Ni2 (Mo,Cr)-type domains are less than a few hundred Angstroms in size, and are visible only with the use of electron microscopy.

Heat Treatment
HAYNES 242 is normally used in the fully-aged condition. However, following forming and welding, a full solution anneal is recommended prior to aging in order to develop the best joint and overall mechanical properties.