Corrosion of Different Types of Steel in Atmospheric and Tidal Marine Environment of Thailand

Abstract

Structural steels which are hot-rolled steel grade SS400 according to JIS G3101, hot-rolled steel grade SM490YA according to JIS G3106 and hot-rolled atmospheric corrosion resisting steel grade SMA490A according to JIS G3114 were exposed from January 2010 until January 2011 to marine and industrial environment at Maptapud industrial estate, Rayong, Thailand. Specimens were exposed in two environmental conditions which were atmospheric zone and tidal zone. The corrosion rate of specimens was investigated by weight loss measurement. Also, environmental conditions such as temperature, relative humidity, and chloride deposition were monitored monthly. Finally, the results showed that corrosion rate at 12 months of carbon steel was higher than that of corrosion resisting steel (SS400 > SM490YA > SMA490A). Furthermore, the specimens in tidal zone showed higher corrosion rate than those in atmospheric zone obviously due to effects of biofouling and wet-dry condition. Also, life cycle cost of a structure constructed by SS400, SM490YA and SMA490A steels exposed to atmospheric and tidal zones was compared. The results can be used for material selection and service life design of steel structures in Thailand.