Evaluation of Creep Damage and Remaining Life along Longitudinal Direction of Ethylene Cracking Tubes

The creep damage states of ethylene cracking tubes which had serviced for three years along longitudinal direction were analyzed with quantitative metallographic analysis method, and the relationship between creep damage levels and remaining life was studied. The damage distribution was obtained along the high level for the tubes. The results show that the creep damage of the tubes was non-uniform. The severest damage occurred at 4~7 m high level of the tubes and where had about 50% remaining life. The creep damage at the other high lever was still in the initial stage and where had 70% ~ 90% remaining life.