Creep Life Assessment of Primary Reformer HP۴۰-NB Modified Steel Tube of an Ammonia Plant

Assessment of creep damage and residual creep life of a cast HP ۴۰ Nb Mod. Reformer tube was performed, wherein the experimental Larson–Miller diagram and area fraction of creep voids were adopted. The state of damage of the tube in service was metallographically analyzed by using light and electron microscopy. Samples from the serviced reformer furnace tube were cut and prepared for void examination and creep test at ۹۴۰ºC-۱۰۰۰ºC under ۲۰-۳۰ MPa stress. Microstructural examination was carried out with an Scanning electron microscope with secondary and backscattered electron detectors. Inter-granular voids in the microstructure of the worked tube as a result of a creep phenomenon are ranked relating to the remaining life.

Keywords:

Creep Life Assessment , Ammonia Plant , HP۴۰ Nb Modified Steel Tube