Failure Analysis of 14Cr1MoR Sreel in High Temperature Sulfur Environment

A coke drum made of 14Cr1MoR steel had a large area of dense corrosion pits near the feed port. The macroscopic morphology and microstructure of the pits were observed by scanning electron microscopy and metallographic microscopy. The composition of the coating and the hardness of the base material in the pits were analyzed by energy spectrum analyzer and hardness tester. The results show that the coating in the pits mainly contained iron, sulfur and carbon. The entrance of the coke drum would cause erosion of the tower wall due to the flow of the medium, making it difficult to form a coke protective layer on the tower wall or causing the attached coke layer to be washed away. Eventually, the high sulfur corrosive medium was directly contacted with the tower body, resulting in more severe high temperature sulfur corrosion.