震击器挠性接头本体断裂失效原因分析

Fracture failure analysis of flexible joint of jar

分析某油田震击器挠性接头失效行为,便于确定该震击器挠性接头本体断裂失效类型、断裂原因,结合该失效井作业工况分析,证实断裂因素。文章基于断裂部位的宏观分析,采用理化分析、扫描电镜微观分析、金相组织分析等方法,对失效的震击器挠性接头开展了系统分析,发现断裂区域基体组织金相、物理性能相比非断裂部分均发生了较大变化,明确其金相变化因素为复杂工况下挠性接头与阻卡物摩擦升温,遇泥浆骤冷淬火,形成马氏体组织,马氏体组织硬度高、韧性差,极易萌生裂纹,在拉应力作用下发生断裂。

By analyzing the failure of the flexible joint of the jar in an oilfield,the fracture failure type and fracture cause of the flexible joint of the jar can be determined.Combined with the operation condition analysis of the failure well,the main influencing factors of fracture failure are determined.Based on the macroscopic analysis of the fracture location,the failure of the flexible joint of the jar was analyzed by means of physical and chemical analysis,scanning electron microscopy and metallographic structure analysis.It was found that the microstructure and physical properties of the matrix in the fracture area changed greatly compared with the nonfracture part.It was clear that the factor of the metallographic change was the friction between the flexible joint and the blocking object under complex working conditions,then the martensite microstructure is formed by quenching in mud.The martensite microstructure has high hardness and poor toughness,and is easy to crack and fracture under tensile stress.