[目的]某高压管汇 Y 型三通管在酸压施工作业过程中发生泄漏.[方法]通过无损探伤、宏观分析、金相分析、化学成分分析、力学性能分析、微观分析、应力计算等手段,对某高压管汇Y 型三通管的材质、断口特征、应力场分布等进行了研究.[结果]现场发生泄漏的三通管在化学成分、拉伸性能、耐冲击性能、金相组织等方面都与库房完好的三通管基本一致,但冲击功均较低,断口呈脆性断裂特征,内壁存在明显的腐蚀产物及腐蚀坑.[结论]三通管发生纵向开裂的主要原因为地面交联酸的腐蚀导致大量腐蚀坑的形成,并在较高的内压作用下造成局部应力集中,超过管材的强度极限.
Causes analysis on cracking of a Y-shaped three-way pipe in high-pressure manifold
[Introduction]A Y-shaped three-way pipe in a high-pressure manifold leaked during acid fracturing operation.[Method]The material,fracture characteristics,and stress field distribution of the Y-shaped three-way pipe were studied by nondestructive inspection,macroscopic observation,metallographic analysis,chemical composition analysis,mechanical properties testing,microscopic characterization,simulative stress calculation,etc.[Result]The chemical composition,tensile properties,impact resistance,and metallographic structure of the failed three-way pipe on site are basically consistent with those of the intact one stored in the warehouse,but both of them feature a low impact energy.The fracture surface shows brittle fracture mechanism.There are obvious corrosion products and pits on the inner wall of the Y-shaped three-way pipe.[Conclusion]The main reason for the longitudinal cracking of the three-way pipe is the corrosion of ground crosslinked acid,which leads to the formation of a large number of corrosion pits,and the local concentration of stress with a value exceeding the strength limit of the pipe under high pressure inside.
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