316L/X65复合管管端的耐腐蚀性研究

    Research on Corrosion Resistance of 316L/X65 Composite Lined Pipe End

    • 摘要: 对油气管道用316L/X65双金属机械复合管管端进行了微观组织分析、成分分析及晶间腐蚀、点腐蚀测试。结果表明,复合管的化学成分符合条件,性能都满足要求。复合管管端堆焊层分为内外两层,Inconel625堆焊层组织主要为奥氏体组织,外层相比内层晶粒更细小,因内层堆焊层的阻隔作用,外层堆焊层没有受到X65基管的影响,保持了良好的耐蚀性能,复合管管端晶间腐蚀测试符合工程应用要求,耐点蚀性能由低到高的顺序为316L-Inconel625焊接区<316L衬管<Inconel625堆焊层,温度升高显著降低管端的耐点蚀性能。316L衬管与Inconel625堆焊层之间的焊接区因电偶作用,使得316L更易发生腐蚀。

       

      Abstract: The microstructure analysis, composition analysis, intercrystal corrosion and point corrosion tests were conducted on 316L/X65 composite lined pipe end for oil and gas pipeline.The results show that the chemical composition of the composite pipe is qualified.The performance indicators are all qualified.The welding layer is divided into two layers, the microstructure of the weld zone is mainly austenite and the crystalline grain of outer layer is smaller than that of the inner layer. Due to the barrier of the inner layer, the outer layer is not effected by X65 substrate, which ensures good corrosion resistance.Pitting corrosion resistance from low to high order is 316L-Inconel625 weld zone< 316L liner < Inconel625 welded layer, increasing temperature significantly reduces the point corrosion resistance of the pipe end.Because of electric coupling, the welded joint between the 316L lined pipe and Inconel625 pile welding layer makes 316L be prone to corrosion.

       

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