Damage assessment of process heater tube

Abstract

The assessment of damages of service-exposed process heater tubes was carried out. Formation of chromium depleted precipitate free zone at the outer surface and inner surface with grain boundary cracks caused major damages to heater tubes. The non-magnetic heater tube in virgin condition turns ferromagnetic during service expose at high temperature due to loss of chromium from solid solution. Early detection of this behaviour is necessary to avoid premature failure of the tube. Detection of ferromagnetic phase in service-exposed tube appears to be the effective for their damage assessment. Therefore magnetic techniques can be used for integrity assessment of the process heater tubes.