Hitachi, Ltd.

Koji Goto

Masaki Murashita

Osamu Matsushima

Yutaka Kobayashi

Takashi Sato

Seizo Nakano

Osamu Isshiki

Takashi Satoh

Masayoshi Hashiura

Hideaki Kikuchi

Shinji Fukuda

Sadao Nakagawa

Katsuro Ota

Hideo Suzuki

Toshimi Matsumoto

Tsutomu Onuma

Tatsuo Yonezawa

Masami Yada

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 welded metal container for a sheath 1 or 1A of gas insulated switch gear comprises a trunk pipe 2, 21 and a branch pipes 3, 31, 32 welded to the trunk pipe 2,21 by arc welding A or laser beam welding LB and flanges welded to the each end portion of the trunk pipe 2, 21 and branch pipes 3, 31, 32 by the laser beam welding. After the arc welding A, the ends of trunk pipe 1, 21 and branch pipes 3, 31, 32 are machined precisely and flanges 4a, 4b, 4c, 4d, 4f and 4g are welded to the end portions of the trunk pipe 2, 21 and branch pipes 3, 31, 32.

Structure of metal container having trunk pipe and branch pipe, and

A method for manufacturing a welded metal container by first arc welding a branch pipe to a trunk pipe. The arc welding of the pipes together causes both of the pipes to be thermally deformed. The end surfaces of the pipes are then cut by a laser cutting or mechanical cutting process so that the ends of the trunk pipe are in parallel and perpendicular to the end of the branch pipe. Subsequently flanges are laser welded to the ends of the pipes without further thermally deforming the pipes. The metal container made by this process can be used as a sheath for a gas insulated switch gear.

Growing community of inventors

Hitachi, Japan

Koji Goto