[en] This patent describes a ferritic alloy having a banitic or martensitic microstructure when heated treated and tempered and characterized by low activation properties, the alloy consisting essentially of: chromium-2.0 to 13 percent by weight; vanadium or, tungsten, or tantalum in a total amount of-0.3 to 1.5 percent by weight; carbon-0.75 to 0.30 percent by weight; manganese-0.01 to 15.0 percent by weight; silicon-0.05 to 1.0 percent by weight; phosphorous-less than 0.01 percent by weight; nitrogen-less than 0.04 percent by weight; sulphur-less than 0.01 percent by weight; copper-less than 0.003 percent by weight; molybdenum-less than 0.12 percent by weight; niobium-less than 0.003 percent by weight; nickel-less than 0.1 percent by weight; the remainder of the alloy being iron