高压管汇由壬翼形螺母的失效原因  

Failure Reasons of Union's Wing Nut of High Pressure Pipe

作　　者：冉小丰[1] 王格一 阳婷[1] 刘少胡[1] 张菲菲 RAN Xiaofeng;WANG Geyi;YANG Ting;LIU Shaohu;ZHANG Feifei(School of Mechanical Engineering,Yangtze University,Jingzhou 434023,China;School of Petroleum Engineering,Yangtze University,Wuhan 430100,China)

机构地区：[1]长江大学机械工程学院,荆州434023 [2]长江大学石油工程学院,武汉430100

出　　处：《腐蚀与防护》2024年第4期92-99,共8页Corrosion & Protection

基　　金：国家自然科学基金(51874045);湖北省科技计划项目(2019CFA093);湖北省教育厅科研计划(T2021004);中油国家油气钻井装备工程技术研究中心开放项目(BOMCOJ118-JKY011-2022)。

摘　　要：页岩气压裂施工中,某高压管汇由壬翼形螺母在服役期间发生断裂,从失效由壬翼形螺母断口位置取样,进行宏观、微观观察,断口能谱分析,硬度测试及金相检验等,并利用ABAQUS软件对由壬翼形螺母进行力学分析,揭示其失效机理。结果表明:螺母内径存在多点疲劳源,断口中央有明显贝纹线且被红褐色(Fe_(2)O_(3))、黄绿色(FeCl_(2))腐蚀产物覆盖;微观断口表面存在球状氧化物,能谱分析表明其含有一定量的Ca、Si元素,螺母原材料中存在较多C类和D类非金属氧化物;硬度和金相组织均达到工艺要求;有限元分析所得产生应力集中的部位与实际断裂位置一致,即靠近母由壬螺纹顶端处,且最大应力为910 MPa,超出材料屈服强度。故由壬翼形螺母失效机理为腐蚀疲劳断裂。最后,提出了相应的改进措施。In the construction of shale gas fracturing,the union's wing nut of high pressure pipe cracked during the service.Samples were taken from the fracture surface of the union wing nut at the failure site for macro and micro observation,fracture energy spectrum analysis,hardness testing,and metallographic examination.ABAQUS software was used to perform mechanical analysis on the union wing nut and to reveal its failure mechanism.The results show that there were multiple sources of fatigue on the inner diameter of the nut,and there were obvious bainitic lines in the center of the fracture surface,which were covered with red brown(Fe_(2)O_(3))and yellow green(FeCl_(2))corrosion products.Spherical oxides were on the surface of the micro fracture,and a certain amount of Ca and Si elements were detected by energy spectrum analysis.There were many non-metallic oxides of class C and class D in the nut raw material.The hardness and metallographic structure met the process requirements.The location of stress concentration obtained from finite element analysis was consistent with the actual fracture location,which was close to the top of the union thread,and the maximum stress value was 910 MPa,exceeding the material yield strength.The failure mechanism of the union wing nut was corrosion fatigue fracture,and the corresponding improvement measures were proposed.

关 键 词：翼形螺母 腐蚀疲劳断裂 失效分析 有限元仿真 

分 类 号：TE983[石油与天然气工程—石油机械设备]