| 摘要 |
PURPOSE:To obtain Ni base alloy having a high strength, further superior stress corrosion cracking resistance in high temp. and pressure water, by specifying metallographic structure and contents of C, Si, Mn, Fe, Cr, Ti, Al, Nb, rare earth element, Mg, Ca in Ni base alloy. CONSTITUTION:The Ni base alloy contains, by weight <=0.08% C, <=0.15% Si, 0.1-1% Mn, <=15% Fe, 20-30% Cr, <=3.5% Ti, <=2% Al, <=7% Nb and <=0.1% one kind or more among respective rare earth element, Mg and Ca and the balance Ni, has gamma' phase and/or gamma'' phase in gamma matrix, and M23C6 are semicontinuously and preferentially pptd. at grain boundaries. For obtaining the alloy, soln. heat treatment composed of heating, holding at 980-1,200 deg.C and cooling, then further aging treatment at one time or more of heating and holding at 550-850 deg.C are applied to alloy having the compsn. In case of cold and hot workings, working by >=10% percentage reduction in area and that at 850-1,250 deg.C by >=20% draft are applied after and before soln. heat treatment, respectively.
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