1.1 This specification covers low-carbon precipitation-strengthened nickel - copper - chromium - molybdenum - columbium alloy steel plates for general applications. The alloys in this specification are strengthened by precipitation in various temperatu This specification covers precipitation-strengthened low carbon nickel copper-chromium-molybdenum-columbium alloy structural steel plates. Precipitation strengthening and precipitation heat treatment shall be performed on the material to enhance and al