Eight-Year Atmospheric Corrosion Exposure of Steels in China

Atmospheric exposures were made of 17 steels at seven sites in China over 8 years. The exposed steels included the most common carbon steels and low-alloy weathering steels. Testing sites covered typical conditions of temperate, subtropical, industrial, marine, rural, humid, and dry environments. Data were regressed, and it was shown that long-term corrosion behavior could be predicted by 4-year exposure data. The environmental factor of humid, hot temperatures was much more important over the long term than the ordinarily acknowledged factors of humidity, sulfur dioxide (SO2), and chloride ion (Cl–) pollution. Apart from the commonly acknowledged effect on corrosion resistance of high phosphorus and copper content, significant effects were observed with variation of copper, phosphorus, and sulfur content in carbon steels and copper-free low-alloy steels in corrosive environments. New ways of developing weathering steels were discussed, and a concept of economic weathering steel was suggested.