Mitsubishi Jukogyo Kabushiki Kaisha

Nippon Steel Corporation

Hiroshi Kondo

Yukio Tomita

Nagio Minami

Koji Tanabe

Akira Usami

Yasuhiro Fukaya

Yoshikazu Yamada

Susumu Izaki

Hidesato Mabuchi

Tamotu Oka

Ryuichiro Ebara

Kazuhide Yamauchi

Katsutoshi Hashima

Masuo Matsumoto

Hiroshi Ishitani

Toshihiko Ohshita

The present invention has an object to provide a steel for a chimney or a gas duct, which is excellent in pitting resistance and rust adhesion in a corrosive environment caused by combustion waste gas in a plant in which the combustion of natural gas occurs. Pitting resistance and rust adhesion are remarkably improved in the steel of the present invention which steel is prepared by using a 5% Cr steel as the base, while reducing an impurity sulfur to not more than 0.010 wt. %, adding titanium within a range of 0.005 to 0.05 wt. %, and further adding nickel alone within a range of 1.0 to 2.5 wt. %, or adding molybdenum alone within a range of 0.10 to 1.0 wt. %, or adding in combination therewith trace amount of copper or molybdenum within a range of 0.10 to 1.0 wt. %.

Steel for chimney or gas duct, excellent in pitting resistance and rust

A method for assembling narrow gap members by welding is described. In the method, separate narrow gap members having spaces therein when assembled are provided and a deformation-preventive material consisting of a water-soluble material or a material capable of being disintegrated with water is filled in each space and is formed with a through groove or hole in the filled preventive material. In this state, the separate narrow gap members are subjected to welding, and immersed in water to remove the deformation-preventive material from each space. The through grooves may have a width larger than a leg length of each penetration bead, in which a heat-resistant flux is filled in each groove. The deformation-preventive material may be covered with a heat-resistant ceramic backing member shaped in a specific form or with a heat-resistant particle layer and a copper member shaped in conformity with an intended size and shape of a penetration bead.

Method for fabricating a structural assembly having narrow gaps

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Hiroshima, Japan

Hiroshi Kondo