EFFECT OF ENVIRONMENT FACTORS ON CORROSIONRATE OF CARBON STEEL IN SEAWATER

摘要

Results of carbon steel exposed to seawater at 5 test sites in China for 8 years were obtained.rnFor the carbon steel exposed at Qingdao and Yulin test sites for 3,6, 9, 12, and 36 months, the numbers ofrnsulfate-reducing bacteria (SRB) and content of FeS in internal rust layers was analyzed. Monthlyrnexposure test in field seawater for one month and simulating test in flowing seawater was carried out atrnQingdao test site. Effects of environmental factors on corrosion rate of carbon steel immersed in seawaterrnwere discussed. Main factors that affect corrosion rate of carbon steel in seawater are temperature,rnflowing rate, fouling and SRB activity. Effect of environmental factors on corrosion rate varied withrnexposure phase. In initial phase, seawater temperature and flowing rate were main factors that affectrncorrosion rate of carbon steel. In transition phase, fouling area became the main factor and effects ofrntemperature and flowing rate decreased. Effect of Sulfate-reducing bacteria activity on corrosion raternincreased. Long-term exposure, SRB activity and fouling area of hard-shell organism became main factorrnaffecting corrosion rate of carbon steel.