Nippon Steel Corporation

Takashi Inoue

Akira Usami

Yuji Kawauchi

Kouji Tanabe

Minoru Naki

Shingo Satoh

The invention relates to a steel plate which exhibits a good resistance to a corrosive atmosphere, containing weakly acidic condensed water comprising SO.sub.2, Cl.sup.- ion, and CO.sub.2 such as the exhaust gas from a boiler which burns LNG. The steel plate having a good corrosion resistance to condensed water characterized in comprising a low C content, a low Mn content and a medium amount of Cr content, and further 0.01% or less of S in an unavoidable impurity, or further comprising at least one element of Si, Al, Cu, Ni, Mo, Nb, V, Ti, Ca, and B. More, the steel plate having a good corrosion resistance to condensed water comprising carbonic acid gas and chloride ion characterized in comprising a low C content, a low Mn content, P, Cu and Ni, and further 0.01% or less of S in an unavoidable impurity, or further comprising at least one element of Si, Al, Mo, Nb, V, Ti, Ca and B.

Steel plate having good corrosion resistance to condensed water

The present invention provides a method for preliminary treatment of molten iron from a blast furnace wherein only desiliconization of the iron is effected. Gaseous oxygen is injected into the molten iron by controlling its supply rate depending on the Si content of the molten iron in such a manner that said rate is increased if the Si content of the iron is high and decreased if the Si content is low.

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Futtsu, Japan

Takashi Inoue