王建才

西安石油大学  机械工程学院  西安  710065

　　摘要：油井管在服役工况下，受到腐蚀性介质，含CO2、H2S和Cl-,井下高温、高压环境的共同作用。油井管在井下的不可见性，使得油井管的破坏程度很难预测。一旦油井管发生破坏，就会造成整口井的报废，造成很大的经济损失。本文首先介绍了疲劳裂纹的萌生和扩展发展现状，再在腐蚀疲劳共同作用下，对油井管材料疲劳裂纹扩展进行研究。试验采用三点弯曲法，在确定试样尺寸后进行ANSYS应力场模拟的基础上，分别对比大气环境和腐蚀介质中疲劳裂纹扩展速率，采用扫描电镜观察产物膜形貌，研究腐蚀疲劳机理。结果表明，大气环境下疲劳裂纹扩展速率受应力大小的影响较大；而腐蚀介质中，疲劳裂纹扩展受到应力频率、应力比、介质腐蚀性、电化学腐蚀的共同影响。

　　关键词：电化学腐蚀腐蚀疲劳裂纹扩展

Fatigue Properties of OCTG Materials In Corrosive Environments

Wang  Jiancai

（ School of Mechanical Engineering , Xi'an Shiyou University, Xi'an 710065 ）

　　Abstract: OCTG subjects to corrosive media , including CO2, H2S and Cl-, downhole temperature, high pressure environment in service conditions. The extent of the damage is difficult to predict the oil well pipe because of OCTG invisible underground .Oil pipe failure occurs once , it will cause the entire scrap wells , causing great economic losses. This paper describes the status of fatigue crack initiation and expansion of development , and then in the joint corrosion fatigue effect on fatigue crack growth OCTG materials research . Using three-point bending test , the sample size in determining the basis for ANSYS stress field simulation, respectively, comparing the atmospheric environment and corrosive media fatigue crack growth rate , using scanning electron microscopy product film morphology and studying the mechanism of corrosion fatigue . The results show that atmospheric environmental fatigue crack growth rate greatly influenced by the size of the stress ; rather in corrosive media , the impact of fatigue crack growth under common stress frequency, stress ratio, medium corrosion , electrochemical corrosion.

　　Keywords : Electrochemical  Corrosion fatigue  Crack growth

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　　王建才：wangjiancai90@126.com