Haynes 244

Haynes 244 alloy is a new Ni-Mo-Cr-W alloy developed for static parts in advanced gas turbine engines which require low thermal expansion at temperatures up to 1400°F (760°C). It offers a higher maximum use temperature than other low thermal expansion alloys currently available, including a 100-200°F (55-110°C) improvement over HAYNES 242 alloy. The alloy is age-hardenable by formation of Ni2 (Cr,Mo,W) domains, which are structurally similar to the strengthening domains in 242 alloy. Judicious alloying with tungsten increased the thermal stability of these domains and lowered the coefficient of thermal expansion. Other important properties such as oxidation resistance and low-cycle fatigue performance are comparable or better than those of 242 alloy.

Haynes 244 alloy is furnished in the annealed condition, unless otherwise specified. The alloy is usually annealed in the range of 2000-2100°F (1093-1149°C), depending upon specific requirements, followed by an air cool (or more rapid cooling) before aging. A water quench is recommended for heavy section components. Aging is performed by holding at 1400°F (760°C) for 16 hours, furnace cooling to 1200°F (649°C) and holding for 32 hours, followed by air cool.