Study on atmospheric corrosion resistance of hot-dip galvanized structural steel in Thailand

This thesis investigated the coating thickness loss of a hot dip galvanized steel in Thailand. The hot dip galvanized steels studied were HDG-SS400 (carbon steel SS400 as the base steel) and HDG-SM490A (carbon steel SM490A as the base steel). The atmospheric exposure test was conducted in 19 different locations. The Locations included a variety of land types such as urban, sub-urban industrial, rural and coastal areas. The thickness loss rate was found in the range of 0.2 to 2.1 µm/y. The severity was categorized into C2, C3 and C4 according to the DPT 1333-61. During the test, it was found that the coating thickness loss was strongly correlated to the rainfall. The regression model was made and used to construct a corrosion map. The constructed corrosion map is publicly available in Corrosion Map App (steelcorrosionmap.com). This map provides the estimated service life of a 100 µm hot dip galvanized steel structure.