Hitachi, Ltd.

Toshimi Tan

Masao Siga

Ryoichi Kaneko

Yasuo Watanabe

Yutaka Fukui

Katsukuni Hisano

Masateru Suwa

Takeshi Onoda

Mitsuo Kuriyama

Shintaro Takahashi

Hidefumi Kajiwara

Yoshimi Maeno

Seishin Kirihara

Takatoshi Yoshioka

Kei Kobayashi

Masahiro Kobayashi

Masao Shiga

Shigeo Sakurai

Yoji Akutsu

Takehiko Yoshida

Hiroshi Miyata

Keiichi Tsuchiya

Takao Mizoi

Kazuhiko Ueda

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&deg; 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.

Steam turbine, rotor shaft thereof, and heat resisting steel

The present invention relates to 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.

The present invention relates to 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.

Steam turbine rotor shaft thereof and heat resisting steel

Combined generator system

A system clarifies the damaged state of a plant, and estimates the life expectancy of the plant so as to administer the integrity of the plant. The system includes an apparatus for estimating the life expectancy of each of various pieces of component constituting the plant, a data base controlling apparatus, an apparatus for estimating the life expectancy of the entire plant, and a plant life extension and evaluation apparatus. The system is capable of making a specific proposal of a life extension plan which is necessary to and effective for the extension of the entire plant, and which is proposed including economical evaluation, thereby facilitating the conservation of the integrity of the plant, and also facilitating the maintenance and control thereof.

System for administering life of plant

A steam turbine rotor shaft comprising the main body of the rotor shaft made of a high Cr steel of martensite structure, and a journal having a plurality of built-up welding layers formed successively said main body, the outer surface portion of the journal being made of steel containing 0.5 to 3 wt % of Cr, and a method of producing same.

Rotor shaft of steam turbine

A rotor shaft for steam turbines has a journal portion to be supported by a bearing. The journal portion is provided with a sleeve for a bearing made of an alloy of bainite structure comprising 0.04 to 0.35% C, 0.2 to 2% Mn, less than 1% Si, 0.5 to 3% Cr, less than 5% Ni, and less than 0.5% V, having yield strength of more than 50 kg/mm.sup.2 and Lt of less than 24. The sleeve is divided into two semicylindrical segments, and they are arranged on a small diameter portion of the shaft adjacent to said journal portion, welded into one piece, and subjected to stress relief treatment at a temperature higher than a temperature of tempering conducted to the sleeve before welding. The welded sleeve is fitted on the journal portion by shrink-fit so that the sleeve can be served as a superior bearing.

Rotor shaft and manufacturing method thereof

A rotor shaft suitable for use as the rotor shaft of a steam turbine. The rotor shaft has a rotor shaft portion made of a Cr alloy steel having martensite structure and containing 8 to 13% Cr. The rotor shaft body is provided with at least one journal portion at which the rotor shaft is rotatably supported by a bearing. The rotor shaft further has a sleeve fitted around each journal portion. The sleeve is divided in the circumferential direction into a plurality of segments which are assembled together by welding or fitting into the sleeve having a circular cross-section. Due to the provision of the sleeve around the journal portion, the rotor shaft made of Cr alloy steel can have improved bearing properties.

Rotor shaft

A moving blade for use in a steam turbine has a turbine rotor carrying a multiplicity of radially outwardly extending moving blades, each moving blade being provided at its leading edge of the radially outer end thereof with an anti-erosion plate attached by welding. The turbine blade has thicknesswise protrusions formed on both surfaces thereof at a portion near the base of the anti-erosion plate where it is attached to the moving blade. Thanks to these thicknesswise protrusions, the moving blade has such a radial distribution of cross-sectional area that the cross-sectional area is greater at the portion where the thicknesswise protrusions are formed than at other portions which are adjacent to the above-mentioned portion of the moving blade in the radial direction. As a result, the stresses at the portion of the moving blade near the base of the anti-erosion plate are reduced.

Moving blade of steam turbine

A moving blade fastening construction comprising moving blade fingers formed in the moving blade root portion and rotor wheel fingers formed in the rotor wheel root portion and arranged so that the fingers of the moving blade are inserted in spaces defined between the fingers of the rotor wheel, thereby to provide at least two engaging portions radially spaced from each other. An average thickness of the moving blade finger is larger than that of the rotor wheel finger which is made of material larger in Young's modulus than the moving blade fingers, whereby stresses induced in the moving blade root portion are made uniform.

Growing community of inventors

Katsuta, Japan

Toshimi Tan