| 摘要 |
PURPOSE:To obtain an Ni base alloy superior in stress corrosion cracking resistance in high temp., high pressure water circumstance by annealing said alloy having a specified compsn., then cold working, next heat treating under a specified condition, further heat treating at just under and above the recrystallization temp. CONSTITUTION:The Ni base alloy consisting of, by weight, <=0.07% C, <=1.0% Si, <=1.0% Mn, 14-35% Cr, 50-80% Ni, 0.05-1.0% Ti, 0.1-1.0% Al, <=0.15% N and substantially the balance Fe with inevitable impurities is melted and manufactured. Said material is cold worked by >=30% reduction after the annealing, then heat treated at 675-725 deg.C for 3-7hr, to aim the precipitation of Cr carbides and the recovery of Cr lack layer. Next, heated at 770-790 deg.C just under the recrystallization temp. for >=1hr, if necessary, cold worked by >=30% reduction, then heat treated by one time or more at 805-830 deg.C just above said temp. for >=0.1hr. In this way, the extremely refining of crystal grains is aimed. The Ni base alloy can be used to steam generator heat transfer tube, etc., in pressurized water reactor.
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