Hitachi, Ltd.

Kei Kobayashi

Hiroyuki Doi

Hajime Toriya

Katsukuni Hisano

Seishin Kirihara

Kenjiro Narita

Toshimi Tan

Takatoshi Yoshioka

Haruyuki Yamazaki

Nobuyuki Iizuka

Masao Siga

Takao Funamoto

Masao Shiga

Kazuhiko Kumata

Takamitsu Nakazaki

Yoji Akutsu

Masahiro Kobayashi

Masami Yada

Keiichi Tsuchiya

Norio Yokoba

Kazuhiko Ueda

A seal structure for a steam turbine is provided, which is capable of suppressing transfer of heat generated by a friction between a rotating portion and a fixed portion to the rotating portion and of suppressing an increase in the temperature of the rotating portion. A labyrinth seal device serves to suppress the amount of steam leaking from a clearance present between each stator blade (fixed portion) of the steam turbine and a rotor (rotating portion). The seal structure for the steam turbine is formed to ensure that permeable spacers made of a permeable metal are provided on the rotor and a seal stationary body and face respective seal fins provided in the labyrinth seal device.

Seals in steam turbine

A Co-base alloy including, by weight, 0.03-0.10% C, not more than 1.0% Si, not more than 1.0% Mn, 20-30% Cr, 15-23% Ni, 3-10% W, 5-10% Ta and 0.05-0.7% Zr, is used as a welding material. A gas turbine nozzle has a crack repaired with a multi-layer weld using the Co-base alloy and a gas turbine for power generation employs the nozzle.

Gas turbine nozzle, power generation gas turbine, co-base alloy and

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

Growing community of inventors

Kitaibaraki, Japan

Kei Kobayashi