Handbook of Case Histories in Failure Analysis
Failure Analysis of Ethylene Cracking Tube
Radiant tubes that failed prematurely in an ethylene cracking furnace were analyzed to determine the cause of their early demise. The tubes were made from austenitic heat-resistant steel and cracked along their longitudinal axis. New and used tubes were compared using scanning electron microscopy, energy dispersive x-ray spectrometry, and mechanical property testing. This provided critical information and revealed that improper coking and decoking had removed the protective oxide layer (Cr2O3) that normally prevents coke deposits from forming on exposed surfaces. Without this layer, coke readily accumulates on the surface of the tubes, fueling carbon diffusion into the metal and a corresponding degradation in microstructure and loss of ductility at high temperatures.
V. Tari, A. Najafizadeh, M.H. Aghaei, M.A. Mazloumi, Failure Analysis of Ethylene Cracking Tube, Handbook of Case Histories in Failure Analysis, Vol 3, Edited By Larry Berardinis, ASM International, 2019, p 140–145, https://doi.org/10.31399/asm.fach.v03.c9001771
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New Handbook: Volume 11B
Now available in the Digital Library! Volume 11B serves as a reference and guide to help engineers determine the causes of failure in plastic components and make corrective adjustments through design and manufacturing modifications.