Alloy 625 is a nickel-chromium-molybdenum alloy with additional of niobium. This provides a high strength alloy without a strengthening heat treatment. The alloy is especially resistant to pitting and crevice corrosion but also other severely corrosive environments. Service temperatures range from cryogenic to about 1000°C. High tensile, creep, and rupture strength together with outstanding fatigue and thermal-fatigue strength in addition to oxidation resistance and excellent weldability are characteristics of this alloy.