Mitsubishi Jukogyo Kabushiki Kaisha

Nippon Steel Corporation

Ryuichiro Ebara

Naohiko Ukawa

Yukio Tomita

Koji Tanabe

Akira Usami

Yoshikazu Yamada

Hidesato Mabuchi

Hiroshi Kondo

Yasuo Nishimura

Tamotsu Yamada

Kazuhide Yamauchi

Katsutoshi Hashima

Masuo Matsumoto

Hideo Nakamoto

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

An austenitic stainless steel for use for high temperature concentrated sulfuric acid which comprises, on weight basis, 0.04% or less of C, 5-7% of Si, 2% or less of Mn, 15-25% of Cr, 4-24% of Ni, 0.01-1.07% of Pd and the rest consisting of Fe and unavoidable contaminant materials. By the incorporation of small amount of palladium in a basal austenitic stainless steel containing the essential three elements of Cr, Ni and Si, a superior corrosion resistance against highly concentrated high temperature sulfuric acid is attained.

Pd-added austenitic stainless steel for use for high temperature

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Hiroshima, Japan

Ryuichiro Ebara