Refractory austenitic alloy, intended to be used at an operating temperature greater than or equal to 1100°C, comprising all the following compounds in percentage by weight: - chromium between 25.0% and 32.0%, - nickel between 50.0% and 61.0%, - aluminum between 1.0% and 6.0%, - niobium between 0.15% and 1.50%, - carbon between 0.05 and 0.60%, - one or more reactive elements in a total content of between 0.010% and 0.060%, a reactive element being defined as one of the rare earths or hafnium, - silicon at 0.30% or less, - manganese at 0.30% or less, - titanium at 0.40% or less, - nitrogen between 0.015% and 0.20%, - vanadium between 0.005% and 1.0%, - iron between 4.0% and 18.0%, to balance the alloy compounds, zirconium, tungsten and sulfur being absent from the alloy, or in the form of impurities respectively at less than 0.030%, less than 0.010% and less than 0.0060%, the alloy further satisfying two criteria connecting the percentages by weight (x Cr, x Al, x C, x Si, x Mn, x Ti, x Nb, x N, x V, x S, x Ni) of all or part of the compounds of said alloy: - a first criterion defined by: 1 − K Al − K S × 2 e 26 − x Cr 0.26 + 1 + K Al × 2 e 2 − x Al 0.4 + 1 + K S × 2 e x S − 0.003 0.1 × x S + 1 ≥ 1 where K Al = 0.1728 + 0.1293 × ln x Al and K S = 0.3089 × e 64 x S; - and a second criterion defined by: - 17.64 + 19.61 x Al - 1.29x Al 2 - 101.46 x N + 450.65 x N 2 - 5.8368 x N 3 + 9.68 x V + 43.12 x Ti + 30.02 x si + 11.42 x Ni - 0.18 x Ni 2 + 35.05 x Nb + 47.92 x Cr - 0.34 x Cr 2 + 13.97 x Mn - 239.66 x C ≥ 1070. - chromium between 25.0% and 32.0%, - nickel between 50.0% and 61.0%, - aluminum between 1.0% and 6.0%, - niobium between 0.15% and 1.50%, - carbon between 0.05 and 0.60%, - one or more reactive elements in a total content of between 0.010% and 0.060%, a reactive element being defined as one of the rare earths or hafnium, - silicon at 0.30% or less, - manganese at 0.30% or less, - titanium at 0.40% or less, - nitrogen between 0.015% and 0.20%, - vanadium between 0.005% and 1.0%, - iron between 4.0% and 18.0%, to balance the alloy compounds, zirconium, tungsten and sulfur being absent from the alloy, or in the form of impurities respectively at less than 0.030%, less than 0.010% and less than 0.0060%, the alloy further satisfying two criteria connecting the percentages by weight (x Cr, x Al, x C, x Si, x Mn, x Ti, x Nb, x N, x V, x S, x Ni) of all or part of the compounds of said alloy: - a first criterion defined by: 1 − K Al − K S × 2 e 26 − x Cr 0.26 + 1 + K Al × 2 e 2 − x Al 0.4 + 1 + K S × 2 e x S − 0.003 0.1 × x S + 1 ≥ 1 where K Al = 0.1728 + 0.1293 × ln x Al and K S = 0.3089 × e 64 x S; - and a second criterion defined by: - 17.64 + 19.61 x Al - 1.29x Al 2 - 101.46 x N + 450.65 x N 2 - 5.8368 x N 3 + 9.68 x V + 43.12 x Ti + 30.02 x si + 11.42 x Ni - 0.18 x Ni 2 + 35.05 x Nb + 47.92 x Cr - 0.34 x Cr 2 + 13.97 x Mn - 239.66 x C ≥ 1070. - a first criterion defined by: 1 − K Al − K S × 2 e 26 − x Cr 0.26 + 1 + K Al × 2 e 2 − x Al 0.4 + 1 + K S × 2 e x S − 0.003 0.1 × x S + 1 ≥ 1 where K Al = 0.1728 + 0.1293 × ln x Al and K S = 0.3089 × e 64 x S; - and a second criterion defined by: - 17.64 + 19.61 x Al - 1.29x Al 2 - 101.46 x N + 450.65 x N 2 - 5.8368 x N 3 + 9.68 x V + 43.12 x Ti + 30.02 x si + 11.42 x Ni - 0.18 x Ni 2 + 35.05 x Nb + 47.92 x Cr - 0.34 x Cr 2 + 13.97 x Mn - 239.66 x C ≥ 1070.