heat resistant austenitic

0.01% to 0.15%, Si: 0.02% to 2%, Mn: 0.02% to 3% a heat-resistant, consisting, in weight percent, C austenitic alloy Ni: 40% to 60%, Co: 8% to 25%, Cr: 15% or more to less than 28%, Nd: 0.001% to 0.1%, B: 0.0005% 0.006%, N: 0.03% or less, O: 0.03% or less, either one or both of Mo: 12% or less and W: less than 4%, and the total content of Mo and W of 0.1% to 12%, at least one selected from Al: 3% or less, Ti: 3% or less, and Nb: 3% or less, and an optionally one or more classes of elements belonging to the first group and / or the following second group, consisting, the first group, Ca: 0.02% or less, Mg: 0.02% or less, La: 0.1% or less and Ce 0.1% or less; consisting, the second group, Ta: 0.1% or less, Hf: 0.1% or less and Zr: 0.1% or less; being the remainder, Fe and impurities, and being, the contents of P and S in the impurities, P: 0.03% and S: 0.01% or less, wherein the parameter represented by F1 formula (1) is 1 or more, and 12 or less, and the parameter F2, represented by formula (2), is 0.035 or less: F1> = 4 x Al + Ti + Nb 2 x ... (1 ) F2> = P + 0.2 x Cr x B ... (2) where, a symbol of an element of the Formula (1), and in Formula (2) represents the content by mass percent of element.