Atmospheric Corrosion Resistance of Stainless Steels in the Laboratory Accelerated Seashore Environment

摘要

Austenitic, ferritic and duplex stainless steels were put into corrosion test for evaluating localized corrosion resistance against seaside environment. Each of them had four kinds of surface finish. Test methods were pitting potential measurement, corrosion test in the simulated seaside environment, optical microscopic observation and surface potential measurement with the Kelvin prove after the atmospheric corrosion exposure. Accelerated atmospheric corrosion was carried out on stainless steel with five spots of 5 micro liter of MgCl_2 deposited on metal surface under the test condition of 40°C and 50%RH for 30days. The pitting potential measurements and accelerated atmospheric corrosion test results showed that the highly corrosion resistant steels in the seashore environment were ferritic 445J2, duplex 329J41 and 329J3L, while austenitic 304, 316 and 316L were susceptible to localized corrosion. The surface potential measurement with the Kelvin probe is very useful for distinguishing the corrosion state whether attacked by pitting corrosion or general corrosion, or in passivity.