目的 考察有机盐钻井液对S135钻杆材料的腐蚀及其疲劳性能的影响。方法 首先利用高温高压釜模拟有机盐钻井液井筒工况环境，并对疲劳试样进行预腐蚀；采用点蚀仪测定试样表面的腐蚀状况，然后利用PQ-6旋转弯曲疲劳试验机在不同弯曲应力条件下对预腐蚀试样和未腐蚀试样的疲劳性能进行测试，计算得出不同存活率下的疲劳强度并绘制出不同存活率下的P-S-N曲线；用体视显微镜和扫描电镜观察预腐蚀试样和未腐蚀试样的疲劳断口形貌，进而得出S135表面腐蚀对其疲劳寿命的影响程度和影响机制。结果 经过腐蚀的试样表面有较多的腐蚀坑，腐蚀坑深度范围在0.4~0.7mm之间；未腐蚀试样的疲劳强度为553MPa，在其疲劳断口只可观察单个疲劳裂纹源；腐蚀后试样的疲劳强度为409MPa，在其疲劳断口可观察到多个疲劳裂纹源；腐蚀疲劳开裂敏感性指数为26%。结论 经过高温高压有机盐钻井液环境腐蚀后，试样表面点蚀严重，腐蚀坑底部存在应力集中并导致裂纹源的形成，多个裂纹源的同时生长加快了裂纹的扩展，最终降低S135钻杆钢的疲劳强度。

Objective Study the impact of organic salt drilling fluid on corrosion and fatigue properties of S135 drill pipe. Methods Simulated organic salt drilling fluid corrosive condition by using autoclave and pre-corroded fatigue samples and measured the sample surface corrosion condition. Maked fatigue test with pre-corrosion samples and normal samples by using PQ-6 bending fatigue test machine under different stress conditions. Calculated fatigue strength under different reliability and drew the P-S-N curve. The surface of samples and fracture were observed by stereomicroscope and scanning electronmicroscopy(SEM).We analysed the influence of corrosion and the fatigue fracture mechanism. Results The surface of the sample had many pits after corrosion and the depth of corrosion pits were about 0.4 ~ 0.7mm; the fatigue strength of normal samples was 553MPa, the fatigue fracture surface had one crack source; the fatigue strength of pre-corrosion samples was 409MPa, the fatigue fracture surface had several crack sources; the fatigue corrosion cracking sensitivity index was 26%. Conclusion The sample surface pitted serious after corrosion in high temperature and pressure environment of organic salt drilling fluid. It had many crack sources and existed stress concentration at the bottom of corrosion pits which caused crack sources. The growth of crack sources at the same time accelerated crack propagation and reduced fatigue strength of S135 drill pipesteel finally.