高应力条件下P550无磁钢的疲劳行为及其断裂机理  

Fatigue Behavior and Fracture Mechanism of P550 Non-magnetic Steel Under High Stress

作　　者：李欣 席文奎[2] 刘克强 魏文澜 杨敏 LI Xin;XI Wenkui;LIU Keqiang;WEI Wenlan;YANG Min(Institute of Drilling&Production Engineering Technology Research,CNPC Chuanqing Drilling Engineering Company Limited,Xi'an 710018,China;College of Mechanical Engineering,Xi'an Shiyou University,Xi'an 710065,China)

机构地区：[1]中国石油集团川庆钻探工程有限公司钻采工程技术研究院,陕西西安710018 [2]西安石油大学机械工程学院,陕西西安710065

出　　处：《热加工工艺》2022年第24期20-24,共5页Hot Working Technology

基　　金：国家自然科学基金项目(51901180);中石油川庆钻探与西安石油大学校企合作项目(CQ2020B-17-3-3)。

摘　　要：石油随钻测量仪器无磁材料在服役过程中的疲劳损伤使其失效风险显著增加,其疲劳寿命与服役安全评估是钻井作业参数选取的重要参考依据。研究选用随钻测量仪器常用无磁奥氏体不锈钢P550进行力学性能试验,依据钻井作业的高应力载荷特性,分别进行由临近屈服强度高周疲劳试验,针对其疲劳寿命分散性的特征,提出在高应力条件下评估P550钢疲劳寿命的方法。结果表明:P550钢的疲劳寿命与Basquin模型较好匹配,随着应力幅的降低,疲劳寿命的分散性明显增大,且在较低应力条件下的试验寿命低于预测寿命,并导致疲劳断裂机制随应力幅的降低而改变。应力幅接近屈服强度时的裂纹扩展机制以周期性解理为主,较低应力幅下为韧性断裂。The fatigue damage of non-magnetic materials of petroleum measurement while drilling(MWD) instruments increases the failure risk significantly. Its fatigue life and service safety evaluation were important references for the selection of drilling operation parameters. The mechanical properties of non-magnetic austenitic stainless steel P550 with MWD instrument were tested. According to high stress load characteristics of drilling operation, the high cycle fatigue tests of adjacent yield strength were carried out respectively. For the characteristics of fatigue life dispersion, a method to evaluate the fatigue life of P550 steel under high stress was proposed. The results show that the fatigue life of P550 steel is well matched with basquin model. The dispersion of fatigue life increases obviously with the decrease of stress amplitude. Moreover, the test life under low stress is lower than the predicted life, and the fatigue fracture mechanism changes with the decrease of stress amplitude. The crack propagation mechanism is mainly periodic cleavage when the stress amplitude is close to the yield strength, and ductile fracture at lower stress amplitude.

关 键 词：高周疲劳 奥氏体钢 疲劳寿命 断裂机理 钻具 

分 类 号：TG115.5[金属学及工艺—物理冶金]