Failure Analysis of Steam Condenser Heat Exchanger Tubes

Failure analysis was carried out on yellow brass tubes that leaked after five years of service in a heat exchanger. The leaked tubes had numerous longitudinal cracks. The service fluid inside the brass tubes was cooling water used to exchange the temperature with hot steam at the shell side. Microscopic examinations and energy dispersive spectroscopic analyses were carried out on the brass tube inside and outside surfaces to understand the root cause of the failure. Microscopic examinations of the tubes at the fracture edges and cracked areas revealed that the tubes suffered severe dezincification, and cracks initiated and propagated from the regions that suffered dezincification, causing the failure of tubes. It is suggested to control the corrosive species in cooling water and select proper material for tubes to avoid the premature failure.