PROBLEM TO BE SOLVED: To provide a steam turbine low-pressure rotor exhibiting strength, toughness, and corrosion resistance in excellent balance.;SOLUTION: The present invention relates to a steam turbine low-pressure rotor including: a low-pressure-side final-stage disc containing precipitation hardening martensitic stainless steel comprising ≤0.1 mass% of C, ≤0.5 mass% of Si, 0.1 to 1 mass% of Mn, 7 to 10 mass% of Ni, 12 to 18 mass% of Cr, 2 to 3 mass% of Mo, 0.5 to 2.5 mass% of Ti, 0.5 to 2.5 mass% of Al, and the balance Fe with inevitable impurities with respect to the total mass; and a high-pressure-side disc containing 3.5% of Ni steel and arranged adjacent to the low-pressure-side final-stage disc, and manufactured by a method including: a step of welding the low-pressure-side final-stage disc to the high-pressure-side disc; and a step of performing heat treatment at 570 to 650°C on a welded member obtained by the welding step and including the low-pressure-side final-stage disc and the high-pressure-side disc.;COPYRIGHT: (C)2015,JPO&INPIT
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