1997 Volume 46 Issue 9 Pages 594-598
Influence of environmental factors on the outbreak of stains on bright annealed stainless steels was investigated by atmospheric exposure tests for 1-6 months.
Atmospheric exposure tests at two coastal-industrial sites along the Japan Sea and the Pacific Ocean showed that the sea-born salt particles from the raging sea presumably caused the stains accompanying pitting corrosions of ferritic stainless steels such as SUS 430.
Comparing the corrosion behavior with the weather data, it is assumed that the frequent and much rainfall reduces the stains by washing the salt particles out and the heavy snowfall also reduces the stains by preventing the particles from attaching to the surface of the stainless steel.
Very light brown spot stains of diameter about 0.5-1.5mm without pitting sometimes break out on the specimens of SUS304 in the season with little salt particle flying and little rainfall. The acid rain and some corrosive fall dust are suspected to cause the stains.
