Abstract: A heat resistant austenitic stainless steel with high strength at elevated temperatures, good steam oxidation resistance, good fire side corrosion resistance, and a sufficient structural stability, suitable for use in boilers operating at high temperatures has a composition (by weight) of. 0.04 to 0.10% carbon (C), not more than 0.4% silicon (Si), not more than 0.6% manganese (MN), 20 to 27% chromium (Cr), 22.5 to 32% nickel (Ni), not more than 0.5% molybdenum (Mo), 0,20 to 0.60% niobium (Nb), 0.4 to 4.0% tungsten (W), 0.10 to 0.30% nitrogen (N), 0.002 to 0.008% boron (B), less than 0.05% aluminium (Al), at least one of the elements Mg and Ca in amounts less than 0.010% Mg and less than 0.010% Ca, and the balance being iron and inevitable impuities.