HIGH CR FERRITARY HEAT-RESISTING STEEL

摘要

A high Cr ferritic heat resistance steel which comprises as components, in mass %, C: 0.08 to 0.13 %, Cr: 8.5 to 9.8 (10.2) %, Mo: 0 to 1.5 %, V: 0.10 to 0.25 %, Nb: 0.03 to 0.08 %, W: 0.2 to 5.0 %, Co: 1.5 to 6.0 %, B: 0.002 to 0.015 % and N: 0.015 to 0.025 %, and optionally one or more of Re: 0.01 to 3.0 %, Si: 0.1 to 0.50 %, Mn: 0.1 to 1.0 %, Ni: 0.05 to 0.8 % and Cu: 0.1 to 1.3 %. The heat resistance steel exhibits significant improvement in long term creep strength, which results in the production of a turbine rotor and turbine parts used in an electric power generation system allowing the use of a steam of an elevated temperature, leading to the improvement of the efficiency of power generation. Further control of the composition based on the parameter for suppressing the acceleration of creep allows the retention of high creep strength for an elongated period of time.