Atmospheric corrosion behavior of steel in Asian areas

摘要

The paper introduces the results of e-Asia Project implemented by Japan, Vietnam and Thailand. Carbon steel (CS) and weathering steel (WS) were exposed in out-door atmosphere of 38 test sites, the environmental parameters as temperature (T), air relative humidity (RH), total of rainfall, airborne salinity and SO_2 deposition rate, were collected in the same period of exposure. The corrosion rate of CS and WS after first year exposure were determined and classified according to ISO standard. The effects of environmental factors to corrosion rate of the steels were analyzed, which showed the increasing corrosion rate of the steels with air temperature when the temperature is lower than 19°C and the decreasing corrosion rate with air temperature when temperature is higher than 19°C. This phenomenon in Asia is different from temperate areas where corrosion rate gets peak at about 10°C. The comparison between the first-year corrosion rates of CS and WS are given in the paper. Especially, the corrosion rates of CS calculated by ISO dose-function and determined by exposure test were compared. The results showed that the actual measured values in almost test sites were higher than the estimated values. Therefore it is confirmed that an estimation formula suited to the Asian regions is needed.