Abstract: An iron, nickel-, chromium base alloy having an austenitic structure, good high temperature features, including a very high resistance to oxidization in an oxidizing atmosphere and to carburization in a carborizing atmosphere at high temperatures, and a high creep fracture resistance. The alloy has the following composition in weight percent: 0.01-0.08 carbon, 1.2-2.0 silicon, from traces up to 2 manganese, 22-29 chromium, 32-38 nickel, 0.01-0.15 rare earth metals, 0.08-0.25 nitrogen, with the balance essentially of only iron and unavoidable impurities and normally occurring accessory elements in normal amounts. The rare earth metals in combination with the silicon content serve to improve the growth of a protecting silicon dioxide-layer on the metal surface, when the metal surface is subjected to high temperatures in oxidizing atmospheres. This counteracts the transportation of metal irons, in particular chromium, out of the alloy so that scaling is minimized.

Abstract: Austenitic steel structural members having improved high temperature creep strength are formed by incorporating a rare earth metal and an alkaline earth metal into a fully austenitic steel.