使用近2a(年)油气线20钢弯头产生了腐蚀穿孔和大量的蚀坑。对失效弯头进行了金相检验、X射线成分分析及X射线衍射结构分析，确定腐蚀产物主要是由于原油中含有氯化物和硫化物，其在原油加工中易产生氯化氢和硫铁化合物；其腐蚀机理主要是属于低温HCl-H2O-H2S腐蚀环境下的腐蚀磨损。提出了防范措施，主要以工艺防腐为主，严格控制氯化物和硫化物的含量，并选用有较好的抗HCl-H2O-H2S腐蚀能力的渗铝钢作为20钢的替代产品。

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.