空心光杆60°管螺纹处断裂分析

Fracture Analysis of Hollow Rod at 60° Pipe Thread

某采油厂使用的空心光杆在运转过程中发生断裂,断裂位于空心光杆与空心抽油杆短接螺纹连接处,即空心光杆60°管螺纹处。对空心光杆60°管螺纹连接断裂原因采取宏观和微观检验、化学成分分析、金相检验和硬度测试等方法进行了分析。结果表明,由于该空心光杆长度不足,采取了与空心短接连接加长的方式,使其能够正常使用,连接时的螺纹没有按照标准采用正确的连接方式,致使引起疲劳断裂。

The hollow rod of an oil production plant broke in the operation process, and the fracture is located at the joint of hollow rod with the hollow sucker rod, that is at 60° pipe thread. The eanses leading to the hollow rod breaking at 60° pipe thread were analyzed by macroand micro-seopic examination, chemical composition analysis, metallographic examination and hardness testing. The results show that because the length of the hollow rod is short, a hollow short shaft is used for lengthening it, which ensures its normal use, but leads to its fatigue fracture because of the incorrect connection way.