HL型抽油杆断裂失效分析

Fracture failure analysis of grade HL sucker rod

通过力学性能检测、显微组织和断口分析,结合服役工况条件,对某油田公司发生的抽油杆断裂失效事故原因进行了分析。结果表明：腐蚀疲劳是导致抽油杆断裂失效的主要原因,抽油杆结构因素造成的局部应力集中导致疲劳裂纹往往起源于抽油杆镦锻过渡区及其前沿30～60 mm范围的区域,同时抽油杆的表面脱碳也会导致抽油杆疲劳寿命的降低。通过优化与改进抽油杆结构以降低抽油杆局部的应力集中、添加缓蚀剂改善抽油杆的服役环境、提高抽油杆表面质量及制备耐蚀涂层等途径可有效提高抽油杆的服役寿命。

Failure causes of HL grade sucker rod were investigated through mechanical properties test,microstructure observation and fracture based on the working condition of the sucker rod. The results show that corrosion fatigue is the main cause to result in the fracture of the rod. The fatigue cracks often originate from the forging transition area of the rod and neighboring region,which can be attributed to the local stress concentration caused by the contour structure. Moreover,surface decarburization can also result in the declining of fatigue expectancy. The service life of the rods can be effectually enhanced by means of optimization of the structure,the use of corrosion inhibitor,the improvement of surface quality and the preparation of anticorrosion coating.