Microstructure Evolution and Element Redistribution in Carburizing Process of Ethylene Cracking Furnace Tube

Carburizing is the main damage form of ethylene cracking furnace tubes. In this process, microstructure tube would change and element diffuses redistributes. After serving for about 41000h, radiation section a plum blossom SC-1 tubular from petrochemical company was tested analyzed in article. Results show that higher service temperature, more serious carburizing tube. inner-wall carburized zone middle temperature with an initial C content 0.1wt%, maximum reaches 1.83wt% number carbides increases obviously as well its organizational morphology changes fine granular to coarse block or chain like type single M23C6 coexistence M23C6, M7C3 MC carbides. The Cr elements are mainly concentrated grain boundary area At same time, diffusion alloy causes deficiency matrix, carbide appears subsurface inner wall.