Alloy 625 (UNS N06625) is a nickel-chromium-molybdenum alloy with an addition of niobium. The addition of molybdenum acts with the niobium to stiffen the alloy matrix, providing a high strength without strengthening heat treatment. The alloy resists a wide range of corrosive environments and has good resistance to pitting and crevice corrosion. Alloy 625 is used in chemical processing, aerospace and marine engineering oil & gas, pollution control equipment, and nuclear reactors.