Abstract: A new alloy is provided having high creep strength at elevated temperatures in the range 1100.degree. to 1200.degree. C. and which is unusually resistant to corrosion and thermal shock and has unusual stress rupture characteristics at the elevated temperatures here involved consisting essentially of, by weight, about 0.3% to 0.9% carbon, 20% to 30% chromium, 26% to 40% nickel, 0.8% to 4.0% manganese, 0.9% to 3.5% silicon, 0.3% to 5.0% tungsten, 3.5% to 8.5% cobalt and the balance iron with residual impurities in ordinary amounts.