CORROSION RESISTING MATERIAL FOR HYDROELECTRIC POWER PLANT, AND HYDROELECTRIC POWER PLANT USING THE MATERIAL

摘要

PROBLEM TO BE SOLVED: To obtain a corrosion resisting material having sufficient corrosion resistance even in highly corrosive water by incorporating a specific composition of Cr, Mo, and the balance essentially Fe. SOLUTION: The corrosion resisting material is composed of a cast stainless steel having a composition consisting of, by weight, 12.5-17% Cr, 0.5-4% Mo, and the balance Fe with inevitable impurities. Owing to this composition, the corrosion resistance of the material in highly electrically conductive water, such as seawater, acidic river water, and river water of =100 gS/cm2 electric conductivity, can be improved. Cr is an important element to improve the corrosion resistance of the material itself in the above conductive fluids. However, the corrosion resistance of the alloy is sharply reduced when its content is above the upper limit value as well as below the lower limit value. Mo is an element which contributes to the improvement of pitting corrosion resistance in conductive water by the coexistence with Cr, but a problem of embrittlement of the material is brought about when its additive quantity exceeds the upper limit value.