Disclosed is an iron-base alloy eminently suited for use as components in nuclear energy installations. The alloy normally contains, in percent by weight, about 20% chromium, about 10% nickel, about 5.5% silicon, about 1.5% carbon, about 8% niobium plus vanadium, about 0.05% nitrogen, less than 1% cobalt as an impurity and the balance iron plus normal impurities found in alloys of this class.