High intensity heat resisting steel and turbine rotor null for high low pressure one somatotype rotor

摘要

PROBLEM TO BE SOLVED: To obtain a high strength heat resistant steel for high- and low- pressure integrated type rotor, combining excellent high temp. creep strength with excellent toughness, by specifying a composition consisting of C, Ni, Cr, Mo, V, N, Nb, and Fe and controlling respective amounts of Si, Mn, P, and S among inevitable impurities. ;SOLUTION: The high strength heat resistant steel can be obtained by providing a composition which consists of, by weight, 0.05-0.2% C, ≤2.5% Ni, 8-11% Gr, 0.3-2% Mo, 0.1-0.3% V, 0.01-0. 08% N, 0.02-0.15% Nb, and the balance Fe with inevitable impurities and further contains, if necessary, one or more kinds among 0. 02-0. 2% Ta, 0.001-0.03% B, 1-2% W, and 1-4% Co and in which respective amounts of Si, Mn, P, and S among the inevitable impurities are limited to ≤0.1%, ≤0.3%, ≤0.015%, and ≤0.008%, respectively. It is preferable that, at the time of producing a high- and low-pressure integrated type turbine rotor from this heat resistant steel, a turbine rotor element body obtained by forging is hardened at 1000-1150°C and tempering is applied at 530-700°C one or more times.;COPYRIGHT: (C)1999,JPO