SAE AMS5940B
Alloy, Corrosion and Heat-Resistant, Bars, Forgings, and Rings, 34Co - 3.0Cr - 28Ni - 3.0Cb(Nb) - 5.5Al - 0.008B - 25.5Fe, Multiple Melted, High Temperature, Oxidation-Resistant, Low Expansion, Solution Heat Treated, Precipitation-Hardenable.