Water leaking through a pinhole from an ASTM A312-TP316L stainless steel pipe was investigated. The pipes had been used for transferring a large amount of potable water. Multiple leaks were found at the circumferential welds of the pipe after a short term of service. An analysis using an optical microscope, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS) was conducted to explore the root cause of the failure.

The results demonstrated that the perforation of the pipe was due to localized corrosion initiated from the inside at the many small pits penetrating to the outside of the pipe. Corrosion pits were located near the heat-affected zone (HAZ), which is the area most susceptible to a corrosion attack. The microbiologically influenced corrosion (MIC) was identified as the primary cause of perforation failure. Corrosion attacks occurred predominantly at the microstructure of ferrite stringers. Spheroidal corpuscles were observed with a high concentration of sulfur, which indicated that sulfate-reducing bacteria (SRB) were creating a biofilm, accelerating the MIC corrosion process. Slightly concave surfaces near the weld of the pipe exhibited evidence of bacterial attack or residue of microorganisms, where the leak occurred.

研究了通过ASTM A312-TP316L不锈钢管的针孔漏水的情况。这些管道已被用来输送大量的饮用水。短期使用后，在管道的圆周焊缝处发现了多次泄漏。进行了使用光学显微镜，扫描电子显微镜（SEM）和能量色散X射线光谱仪（EDS）的分析，以探究故障的根本原因。

结果表明，管子的穿孔是由于局部腐蚀从内部开始的，这些腐蚀是从内部开始的，许多小孔都渗入到管子的外部。腐蚀坑位于热影响区（HAZ）附近，该区域是最容易受到腐蚀侵袭的区域。微生物学上的腐蚀（MIC）被确定为穿孔失败的主要原因。腐蚀侵蚀主要发生在铁素体纵梁的微观结构上。观察到球状小球含有高浓度的硫，这表明硫酸盐还原细菌（SRB）正在形成生物膜，从而加速了MIC腐蚀过程。管道焊缝附近略微凹陷的表面显示出细菌入侵或微生物残留的迹象，即发生泄漏的地方。