HEAT-RESISTANT AUSTENITIC ALLOY, HEAT-RESISTANT PRESSURE-RESISTANT MEMBER COMPRISING THE ALLOY, AND PROCESS FOR PRODUCING THE SAME

摘要

A heat-resistant austenitic alloy which contains 0.02-0.15%, excluding 0.02%, C, up to 2% Si, up to 3% Mn, up to 0.03% P, up to 0.01% S, 28-38% Cr, 40-60%, excluding 40%, Ni, up to 20% (including 0%) Co, 3-15%, excluding 3%, W, 0.05-1.0% Ti, 0.005-0.2% Zr, and 0.01-0.3% Al and has a N content up to 0.02% and a Mo content less than 0.5%, with the remainder being iron and impurities, and which satisfies relationships (1) to (3).  The alloy has a high creep rupture strength, has satisfactory toughness even when used at a high temperature over long, and has excellent hot workability.  This heat-resistant austenitic alloy may contain a specific amount of one or more elements selected from Nb, V, Hf, B, Mg, Ca, Y, La, Ce, Nd, Sc, Ta, Re, Ir, Pd, Pt, and Ag. P=3/{200(Ti+8.5×Zr)}               (1) 1.35×Cr=Ni+Co=1.85×Cr              (2) Al=1.5×Zr                            (3)