复合管焊接接头整管段应力腐蚀试验方法研究

西南某高酸性气田拟采用双金属复合管作为内腐蚀控制手段，为了评估复合管焊接接头的耐腐蚀性能，根据其结构特点，建立整管段试件有限元力学模型，并通过加载应力应变测试试验验证了有限元模型的准确性，确定出焊缝合理的应力槽形式和试验总压。采用自主研制的双金属复合管整管段的腐蚀评价装置和方法，开展了X52/825冶金复合管焊接接头在苛刻应力状态和腐蚀工况下的耐蚀性能评价，结果表明，X52/825冶金复合管焊接接头在模拟工况下，经720 h腐蚀实验后，均未出现破裂或刺漏，100%射线探伤检验结果显示X52/825冶金复合管焊接接头无开裂性裂纹，具有良好的耐蚀性能。研究结果为酸性气田复合管的性能评估和安全使用提供了技术借鉴。

A Study on Stress Corrosion Test Method for Welded Joint of Whole Pipe Section of Composite Pipe

A southwest high acid gas field planed to use bimetallic composite pipes as internal corrosion control means. In order to evaluate the corrosion resistance of welded joints of composite pipes, a finite element mechanical model of the whole pipe section was established according to its structural characteristics. The accuracy of the finite element model was verified by loading stress-strain test, and the reasonable form of stress groove and total test pressure of welds were determined. Finally, the corrosion resistance evaluation of welded joint of X52/825 metallurgical composite pipe under severe stress and corrosion conditions was carried out by independently developed corrosion evaluation device and method for the whole pipe section of bimetallic composite pipe. The results show that the welded joint of X52/825 metallurgical composite pipe is not cracked or punctured after 720 hours corrosion test under stimulated working conditions. The results of 100% X-ray flaw detection show that the welded joints of X52/825 metallurgical composite pipes have no cracks, showing its good corrosion resistance. The results of this research provide theory and reference for the performance evaluation and safety use of composite pipes in acid gas fields.