钻井工具接头内螺纹牙型底部开裂原因  

Causes of cracking at the bottom of internal screwed teeth in drilling tool joint

作　　者：娄琦 韩新利 赵金兰 赵冰[2] 宋寰 LOU Qi;HAN Xinli;ZHAO Jinlan;ZHAO Bing;SONG Huan(CNPC Tubular Goods Research Institute,Xi’an 710077,China;PetroChina Changqing Oilfield Company,Xi’an 710018,China)

机构地区：[1]中国石油集团工程材料研究院有限公司,西安710077 [2]中国石油长庆油田分公司,西安710018

出　　处：《理化检验（物理分册）》2022年第4期73-76,共4页Physical Testing and Chemical Analysis(Part A:Physical Testing)

基　　金：中国石油天然气集团公司基础研究基金项目(2019D-5008;2019Z-03)。

摘　　要：某钻井工具接头在短期使用后出现周向裂纹,采用化学成分分析、硬度测试、金相检验等方法对其开裂原因进行了分析。结果表明:该钻井工具接头的裂纹为疲劳裂纹,裂纹萌生于内螺纹接头与杆柱体最临近的螺纹牙型底部,在周期性疲劳载荷的作用下,裂纹沿螺纹牙型底部周向扩展,同时向外壁方向扩展,最终外壁发生开裂。The circumferential cracks appeared in a drilling tool joint after short-term use.The cracking causes were analyzed by chemical composition analysis,hardness test and metallographic examination.The results show that the crack of the drilling tool joint was fatigue crack,and the crack initiated at the bottom of the thread tooth profile closest to the internal thread joint and the rod body.Under the action of periodic fatigue load,the crack extended circumferentially along the bottom of the thread tooth profile,and at the same time extended outward,and finally the outer wall cracked.

关 键 词：钻井工具接头 内螺纹 疲劳裂纹 应力集中 

分 类 号：TG115[金属学及工艺—物理冶金]