表面技术2016，Vol.45Issue(3)：17-23,7.DOI:10.16490/j.cnki.issn.1001-3660.2016.03.004
S135钻杆钢预腐蚀后的弯曲疲劳性能
Bending Fatigue Properties of S135 Drill Pipe Steel after Pre-corrosion
摘要
Abstract
ABSTRACT:Objective To study the impact of organic salt drilling fluid on corrosion and fatigue properties of S135 drill pipe. Methods The organic salt drilling fluid corrosive condition was simulated by using autoclave and the fatigue samples were pre-corro-ded. The corrosion status of sample surface was measured by pitting instrument. The fatigue test with pre-corrosion samples and normal samples was conducted by using PQ-6 bending fatigue test machine under different stress conditions. The fatigue strength under different reliability was calculated and the S-N curves were drawn. The fatigue fracture morphologies of corroded and normal samples were observed by stereomicroscope and scanning electron microscopy ( SEM) . Then the influence of surface corrosion of S135 drill pipe material on its fatigue life as well as the influencing mechanism was obtained. Results The surface of the corroded sample had many pits and the depth of corrosion pits was in range of 0. 4~0. 7 mm. The fatigue strength of normal samples was 553 MPa, and the fatigue fracture surface had a single crack source, while the fatigue strength of pre-corroded samples was 409 MPa, and the fatigue fracture surface had several crack sources. The fatigue corrosion cracking sensitivity index of S135 drill pipe material was 26%. Conclusion The sample surface was pitted seriously after corrosion in high-temperature and pressure environ-ment of organic salt drilling fluid. The existence of stress concentration at the bottom of corrosion pits led to formation of crack sources, and the simultaneous growth of multiple crack sources accelerated crack propagation and finally reduced the fatigue strength of S135 drill pipe steel.关键词
S135钻杆材料/弯曲疲劳试验/点蚀/应力集中/断口分析/疲劳断裂Key words
S135 drill pipe steel/bending fatigue test/pitting/stress concentration/fracture analysis/fatigue fracture分类
矿业与冶金引用本文复制引用
李彬,曾德智,施太和,刘飞,喻智明..S135钻杆钢预腐蚀后的弯曲疲劳性能[J].表面技术,2016,45(3):17-23,7.基金项目
国家自然科学基金(51374177) （51374177）
西南石油大学中青年骨干教师培养计划资助Fund:Supported by the National Natural Science Foundation of China (51374177) and the Youth Backbone Teachers Support Program of Southwest Petrole-um University （51374177）
