ANALYSIS OF THE SEWAGE PIPE CORROSION IN HUANGDAO OIL TERMINAL
黄岛原油码头管道腐蚀的原因分析

Polluted seawater by the petroleum has a violent corrosivity on sewage tube (thickness 8mm) welded by mild steel. The steel sewage tube lasted only six years as a result of the corrosion perforation.Spot investigation, water quality analysis, culture of bacteria, metallographic test and electrochemical measurement etc. show that cause for corrosion is the higher sulphur content of the oil, which becomes a depolarizer, thus accelerates corrosion. Meanwhile the mud, sand, or oil sediments form a "occluded zone", which also promotes localized corrosion in steel pipes.