Abstract: This paper analyzes the crack failure of regenerated flue gas bending pipe in continuous catalytic reforming unit (CCR), and conducts macro-morphology, microstructure, macro-micro fracture, SEM and EDX non-damage detection on the crack location. The flow of medium in the pipe and the position of the pipe are analyzed by means ofnumerical simulation. The results show that the bending pipe increases the medium flowvelocity, leading to the inner wall of the elbow to produce pits quickly under constant washing, which finally causes stress corrosion cracking (SCC) under the action of Cl-. In order to avoid cracks during service again, the position of the branch pipe and main pipe is improved so that the fluid gets a greater buffer at the elbow and reduces the corrosion strength.

Key words: CCR, bendingpipe, crack, washing, SCC, failure analysis