Abstract
In hot spring facilities in Kusatsu, Gunma Prefecture, in about two months, SUS304 stainless steel handrails corroded and dissolved uniformly in acid sulfate-chloride spring water containing hydrogen sulfide. Corroded samples were analyzed, remaining handrails were observed closely, an immersion test was conducted at the sources of springs, and corrosion potentials were measured. The result showed that the causes of the corrosion were low pH (pH 2 or less) and the corrosion action of free hydrogen sulfide. Because the handrails corroded in only the type of spring water containing hydrogen sulfide at the two sources of springs with a pH of 2 or less, hydrogen sulfide had a particularly significant impact on the corrosion and accelerated the active dissolution of SUS304 stainless steel. As a measure against corrosion, titanium instead of SUS304 stainless steel was used for handrails. Rusting or local corrosion was not observed about 18 months after use.
