Hitachi, Ltd.

Masami Yada

Takao Funamoto

Hideo Suzuki

Nobuyuki Iizuka

Toshimi Matsumoto

Kazuhiko Kumata

Tsutomu Onuma

Takamitsu Nakazaki

Kei Kobayashi

Masaki Murashita

Tsugio Yoshikawa

Tatsuo Yonezawa

Koji Goto

Osamu Matsushima

Junzo Komatsu

Norio Yokoba

Masakazu Midorikawa

Michio Kitamura

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

Method of welding a carbon steel and a austenitic stainless steel involves using high density energy beam like a laser beam or electron beam. Welding using high density energy beam is effective to obtain a high precision welding. For the purpose of obtaining both high precision and no cracks, and no deformation, the method of the invention controls the structure of a weld portion to be a mixed structure of an austenitic structure and not greater than 20 wt % of a ferritic structure.

Method of welding a carbon steel and an austenitic stainless steel

A water turbine runner has a plurality of vanes, each made of a rolled steel plates which contains, by weight, 0.01 to 0.10% of C, 0.10 to 1.0% of Si, 0.10 to 2% of Mn, 2 to 7% of Ni, 10 to 15% of Cr and 0.10 to 4% of Mo, 71.9 to 87.7% of Fe, and which has a metallic structure mixture containing, by volume, martensite and 10 to 35% of residual austenite. Each of the vanes is made of a plurality of plate pieces, cut out from the rolled steel plate, press-formed in a shape of a part of the vane and joined by welding into the complete vane.

Water-turbine runner and process for manufacturing the same

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Hitachi, Japan

Masami Yada