油井的双公短节在提升过程中发生断裂,通过对材料的化学成分分析、力学性能检测、微观断口分析、金相检验及点腐蚀试验等手段对断裂原因进行了分析.分析结果表明,双公短节内壁在含有硫、氯等腐蚀性介质的作用下,首先产生腐蚀坑,并在点蚀坑底萌生氢致裂纹,最后在外力作用下,在腐蚀严重的部位发生断裂.

A double male joint was broken in oil well during elevation.Through the analyses of chemical composition,mechanical properties,micro-fracture and metallographic examination,pit corrosion test,etc,the broken reasons of the double male joint were analyzed.The existence of corrosive media such as S and Cl on the inner wall of the double male joint induced pitting corrosion firstly and then hydrogen induced cracking from the pit bottom.When the external force was loaded,the fracture occured at the site of serious corrosion.