某油田井口90°输气弯管发生了穿孔失效。通过宏观检查、金相检验、扫描电镜及能谱分析，对弯管穿孔失效原因进行了分析；采用有限元法建立了气固两相流条件下颗粒对弯管的冲蚀模型，并计算得到了弯管冲蚀破坏的危险区域和主要影响因素。结果表明：外弧面内壁位置的冲蚀速率最高，冲蚀速率随着固体颗粒直径、质量浓度和流速的增大而增大；20钢在低温服役时发生了韧脆转变，出现了低温脆性，在固体颗粒的不断冲击下，弯管最终发生穿孔失效。

Perforation failure occurred in 90° elbow pipe at wellhead of an oil field. The causes of perforation failure were analyzed by macroscopic inspection, metallographic examination, scanning electron microscopy and energy spectrum analysis. The erosion model of particles on elbow pipe under the condition of gas-solid two phase flow was established by the finite element method. Also, the dangerous area and the main influencing factors of the elbow erosion damage were calculated. The results show that the erosion rate on the inner wall of the outer arc was the highest, and the erosion rate rose with the increase of diameter, mass concentration and flow rate of solid particles. The ductile-brittle transition and low temperature brittleness occurred on 20 steel at low temperature, and eventually the perforate failure happened under the continuous impact of solid particles.