某油田进行酸化验抽作业时发现一根P110S钢级油管沿横向完全断裂，通过宏观观察、化学成分分析、金相检验、力学性能试验、扫描电镜及能谱分析等方法对断裂原因进行了分析。结果表明：该油管断裂由硫化物应力腐蚀开裂导致，裂纹起始于油管上扣端大钳夹持区的咬伤牙痕内；工作应力和牙痕底部的应力集中、含硫腐蚀介质及油管强度偏高共同导致该油管发生了硫化物应力腐蚀开裂。

A P110S steel grade oil tubing was found fractured completely along the transversal direction during acidification operation in an oilfield. The fracture reasons of the oil tubing were analyzed by means of macro observation, chemical composition analysis, metallographic examination, mechanical property test, scanning electron microscope, energy spectrum analysis and so on. The results show that the fracture of the tubing was caused by sulfide stress corrosion cracking. The cracks initiated from the bottom of the tooth mark in the clamping area of the oil tubing. The work stress and the stress concentration at the bottom of the tooth mark, the sulfur-containing corrosive medium and the high strength of the tubing, these three causes resulted in the sulfide stress corrosion cracking of the tubing.