Patent ID: 8801877

Claim:
A method for manufacturing a heat resistant pressure member excellent in creep resistance and structural stability in a high temperature range which is made from an austenitic heat resistant alloy comprising, by mass percent, C: more than 0.02% to not more than 0.15%, Si: 2% or less, Mn: 3% or less, P: 0.03% or less, S: 0.01% or less, Cr: more than 30% to 38%, Ni: more than 40% to not more than 60%, Co: 7.2 to 20%, W: more than 3% to not more than 15%, Ti: 0.53 to 1.0%, Zr: 0.005 to 0.2%, Al: 0.01 to 0.3%, N: 0.02% or less, and Mo: less than 0.5%, with the balance being Fe and impurities, in which the following formulas (1), (3) and (4) are satisfied: P≦3/{200(Ti+8.5×Zr)} (1), Al≧1.5×Zr (3), 1.35×Cr≦Ni+Co≦1.85×Cr (4); wherein each element symbol in the formulas (1), (3) and (4) represents the content by mass % of the element concerned, and wherein the austenitic heat resistant alloy is treated in sequence by the following steps (i), (ii) and (iii): step (i): heating to 1050 to 1250° C. at least once before final hot or cold working; step (ii): carrying out a final hot or cold plastic working such that a reduction of area is 10% or more; step (iii): carrying out a final heat treatment in which cooling is performed after heating and holding at a temperature in the range of 1100 to 1250° C.