TRACK: Failures/Failure Analysis
Microbial Influenced Corrosion has been an expensive problem, and has caused non-containment failures during the construction and commissioning of chemical, petroleum refinery, and gas processing plants. Elimination of water from hydrotested pipes has been an ongoing issue. Many failures of austenitic stainless steel pipe have occurred due to MIC in TP 304/304L piping carrying water.
Use of modified waveform Gas Metal Arc Welding (processes (STT, RMD, CMD) has gained wide acceptance in pipe fabrication, displacing GTAW in many instances. A simple experiment is being conducted to assess whether a GTAW root provides some protection from MIC when compared to STT/RMD/CMD processes. Are waterborne microbes more likely to latch on to the "sugared" root pass surface of STT/RMD/CMD welds compared to GTAW smooth surface root passes deposited using an inert gas? The ongoing experiment intends to explore this question in a simple manner, and it is expected to provide results that may affect choice of welding process during initial materials selection of piping intended for water services.