Root Cause Failure Analysis of Superheated Steam Tube at a Petrochemical Plant

摘要

The aim of the present study is to determine root causes of failure in a steam tube at a petrochemical plant. In this order, light microscope and scanning electron microscope (SEM) were carried out observing the microstructures and hardness measurements were used for metallurgical evaluation. In addition, phase composition of deposits were studied by using X-ray diffraction (XRD). Based on the results, "short-term overheating" was recognized as the root cause of steam tube failure. Metallographic studies showed distributed martensite as a brittle phase in ferritic matrix in the microstructure of damaged area, while in the microstructure of non-damaged area only pearlite and ferrite were seen. These findings were confirmed by hardness measurement results as well.