Official Answer
Answer
Hastelloy C-276 (UNS N10276) is a nickel-molybdenum-chromium alloy with excellent resistance in the most severe environments, including wet chlorine gas and strong oxidizing salts. Its spring properties are achieved through cold reduction, but it does not respond to age hardening like Inconel. Consequently, its yield strength is lower ($S_y \approx 800-900$ MPa), requiring the spring to be physically larger to achieve the same load as a 17-7PH spring. In chemical injection valves, its resistance to 'pitting' and 'crevice corrosion' outweighs its lower mechanical efficiency.
