| 摘要 |
PURPOSE:To obtain a precipitation hardening Ni-base alloy having excellent resistance to corrosion as well as high strength and high toughness by subjecting the Ni-base alloy which contains Cr at a high rate and Ti at a decreased rate and is added mainly with Nb and Al to specific hot working and heat treatment in combination. CONSTITUTION:An alloy contg. <=0.050% C, <=0.50% Si, <=2.0%Mn, 45-60% Ni, 18-27% Cr, <=0.40% Ti, <=1 kind of 2.5-5.5% Mo and <=11% W, >=1 kind among 0.3-2.0% Al, <=0.015% P and 2.5-5.0% Nb, <=0.0050% S, <=0.030% N and a specific amt. of Cu, Co, Mg, Fe, etc. is melted. Such alloy is subjected to hot rolling to >=50% reduction rate of area at 1,200-800 deg.C and is held for 3min-5hr at 1,000-1,200 deg.C. The alloy is cooled at a cooling rate above air cooling and is subjected to >=1 time of aging treatment at 500-750 deg.C. The precipitation hardening Ni-base alloy having the excellent resistance to stress corrosion cracking and hydrogen cracking is obtd.
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