FAILURE ANALYSIS OF 20 STEEL BEND CORROSION IN OIL-GAS LINE

The 20 steel-bend used not long time had been corroded and perforated. In order to detect the corrosion mechanism, take precautions against corrosion, analyzed the structure of the steel-bend through microstructure examination、 X-ray and X-ray diffraction (XRD), ascertained the corrosion products were chloride and sulphide which could produce hydrogen chloride and iron sulfur compound. And the corrosion mechanism mainly belonged to corrode and wear under the HCl-H2O-H2S condition in low temperature. And proposed the preventive measures which mainly was technics anticorrosive, and strictly controlled the concentrations of chloride and sulphide, and chose anticorrosive aluminized steel as substitution product.