Turbine rotor and manufacturing method of turbine rotor

摘要

A turbine rotor has suitable strength and toughness without causing soaring manufacturing costs and prolonged manufacturing time. The turbine rotor is constructed by welding a rotor member for high temperature made of high Cr steel to a rotor member for low temperature made of low Cr steel. The high temperature rotor member is formed from high Cr steel of which the nitrogen content is 0.02% or higher by mass %. A filler material welds the high temperature rotor member and the low temperature rotor member together, and is a 9% Cr-based filler material of which the nitrogen content is 0.025% or lower by mass %.

主权项

1. A turbine rotor formed by welding a rotor member made of high Cr steel and a rotor member made of low Cr steel, comprising:
the rotor member made of high Cr steel containing 0.02% to 0.1% of nitrogen by mass % to reinforce strength and having a chemical composition (1) or (2), where
(1) contains, by mass %, C: 0.05 to 0.4, Si: 0.35 or less, Mn: 2 or less, Ni: 7.0 or less, Cr: 8 to 15, Mo: 0.1 to 3, V: 0.01 to 0.5, N: 0.02 to 0.1, Nb: 0.2 or less, and balance Fe, and(2) contains, by mass %, C: 0.05 to 0.4, Si: 0.35 or less, Mn: 2 or less, Ni: 7.0 or less, Cr: 8 to 15, Mo: 1 or less, V: 0.01 to 0.5, N: 0.02 to 0.1, Nb: 0.2 or less, W: 0.1 to 3, and balance Fe; the rotor member made of low Cr steel having a chemical composition (3) or (4), where
(3) contains, by mass %, C: 0.2 to 0.35, Si: 0.35 or less, Mn: 1.5 or less, Ni: 0.2 to 2.0, Cr: 1.5 to 3.0, Mo: 0.9 to 1.50, V: 0.2 to 0.30, and balance Fe, and(4) contains, by mass %, C: 0.4 or less, Si: 0.35 or less, Mn: 1.20 or less, Ni: 3.0 to 4.5, Cr: 1.5 to 2.5, Mo: 0.1 to 1.50, V: 0.01 to 0.3, and balance Fe; and a weld that connects the rotor member made of high Cr steel and the rotor member made of low Cr steel together, the weld comprising a filler material that has a chemical composition (5), where
(5) contains, by mass %, C: 0.10 or less, Si: 0.30 or less, Mn: 1.20 or less, Ni: 1.0 or less, Cr: 8.00 to 9.50, Mo: 0.60 to 1.00, V: 0.10 to 0.30, N: 0.001 to 0.025, Nb: 0.04 or less, and balance Fe.