录井钢丝的失效分析

分析录井钢丝的断裂原因,对事故钢丝残样和未使用钢丝进行宏观形貌、化学成分、力学性能和金相组织的对比分析,在宏观形貌分析中可见事故钢丝表面有明显被腐蚀的痕迹。对钢丝表面的点蚀坑进行能谱分析,测定腐蚀残留物,对断口进行扫描电镜分析。结果显示油井中的腐蚀介质是引起钢丝断裂的主要原因,钢丝表面腐蚀坑和裂纹源区均含有S元素,且腐蚀坑内S元素的质量分数达到2.30%,该腐蚀性介质使录井钢丝表面发生腐蚀,进而形成腐蚀坑。在腐蚀性介质和外加载荷的双重作用下,裂纹持续扩展,直至发生断裂。

Failure analysis of well logging wire

To analyze the fracture reason of well logging wire. The failure and unused steel wire were compared and analyzed about macro-profile, chemical composition, mechanical properties and metallurgical structure. The trace of corrosion on failure steel wire surface was observed obviously when it was analyzed on macro-profile. Pitting of steel wire surface was energy spectrum analyzed to determine corrosion residue. Fracture was analyzed by SEM. Results show that the corrosive medium in oil well is the main reason of steel wire fracture, both steel wire surface corrosive pit and crack origin contain S element, the mass fraction of S element in corrosive pit reaches 2.30% , the corrosive ＂medium causes corrosion on well logging steel wire surface, then forms corrosion pit. Under the dual influence of corrosive medium and applied load, crack ex- pands continuously, until the fracture happens.