초록 ▼

A steam turbine comprising a rotor shaft integrating high and low pressure portions provided with blades at the final stage thereof having a length not less than 30 inches, wherein a steam temperature at first stage blades is 530.degree. C., a ratio (L/D) of a length (L) defined between bearings of

A steam turbine comprising a rotor shaft integrating high and low pressure portions provided with blades at the final stage thereof having a length not less than 30 inches, wherein a steam temperature at first stage blades is 530.degree. C., a ratio (L/D) of a length (L) defined between bearings of the rotor shaft to a diameter (D) measured between the terminal ends of final stage blades is 1.4 to 2.3. This rotor shaft is composed of heat resisting steel containing by weight 0.15 to 0.4% C, not more than 0.1% Si, 0.05 to 0.25% Mn, 1.5 to 2.5% Ni, 0.8 to 2.5% Cr, 0.8 to 2.5% Mo and 0.15 to 0.35% V and, further, the heat resisting steel may contain at least one of Nb, Ta, W, Ti, Al, Zr, B, Ca, and rare earth elements.

대표청구항 ▼

[ What is claimed is:] [1.]1. A steam turbine having a rotor provided with a mono-block rotor shaft, multi-stage blades fixed on the mono-block rotor shaft from a high pressure side at which a steam inlet temperature of first stage blades is not less than 530.degree. to a low pressure side at which

[ What is claimed is:] [1.]1. A steam turbine having a rotor provided with a mono-block rotor shaft, multi-stage blades fixed on the mono-block rotor shaft from a high pressure side at which a steam inlet temperature of first stage blades is not less than 530.degree. to a low pressure side at which are provided final stage blades having a length not less than 40 inches for the mono-block rotor shaft rotated at 3000 rpm or a length not less than 33.5 inches for the mono-block rotor shaft rotated at 3600 rpm, said final stage blades comprising a Ti-based alloys:wherein at least the first stage blades at the high pressure side comprise a martensitic steel containing, by weight, 0.20 to 0.30% C, not more than 0.5% Si, not more than 1% Mn, 10 to 13% Cr, 0.5 to 1.5% Mo, 0.5 to 1.5% W, and 0.1 to 0.35% V; andwherein remaining blades, with the exception of said at least first stage blades at the high pressure side made of said martensitic steel and said final stage blades, comprise a martensitic steel containing by weight, 0.05 to 0.15% C, not more than 0.5% Si, not more than 1% Mn, 10 to 13% Cr, not more than 0.5% Ni, and not more than 0.5% Mo.