Failure Mechanism Analysis of Corrosion Perforation of an Ethylene Cracking Tube

An ethylene cracking tube was perforated because of corrosion.The macro corrosion morphology,chemical composition of the material,metallographic examination,EDS and service conditions were investigated and improving measures were suggested.The results showed that the side faced to the fire directly was heated to so high temperature that the protective film of Cr2O3 was destroyed,which caused the metal dusting.The discussion of the failure mechanism demonstrated that at the temperature over 800 ℃ metal dusting failure could also happen for HP40 material mainly because of the destruction of Cr2O3 protective film.