Steam turbine blade, and steam turbine and steam turbine power plant using the same

摘要

The subject-matter of the invention is a steam turbine blade having a blade length above 1143 mm (45 in) for a 3000 rpm turbine or a blade length above 952 mm (37.5 in) for a 3600 rpm turbine, said blade is made of a martensite steel having a 20 °C V-notch impact value of at least 5.6 kg·m/cm 2 and a 20 °C tensile strength of at least 144 kg/mm 2 ,
which martensite steel consisting of - in wt.-% -
C 0.19 to 0.23 %, Mo 2.5 to 3.0 %, Si less than 0.5 %, Mn less than 1.5 %, Ni 2.0 to 3.5 %, Cr 8.0 to 13.0 %, V 0.05 to 0.35 %, N 0.04 to 0.15 %, at least one of Nb and Ta 0.02 to 0.3 % in total and balance Fe.