ANALISA KERUSAKAN PIPA EKSPAN PADA KETEL UAP UNIT PENGOLAHAN MINYAK BUMI[Failure Analysis of Tube Expand in Oil Processing Unit Boiler System]

Abstract

This paper discussed about combinations between fatigue and corrosion as a factor that cause expand tube leaking of boiler, and give solution to prevent similar case in future. Examinations are carried out such as visual and macrography, metallography, hardness testing, chemical composition analysis, SEM (scanning electron microscope) and EDS (energy dispersive spectroscopy). Microstructure examination shows transgranular cracks propagated from outside into inside diameter. Additional data obtained from EDS analysis confirm the presence of iron oxide as a corrosion product on the surface of expand tube. Corrosion was occured due to imperfect firing process on boiler system, while fatigue failure was initiated by cyclic of loading and temperature. This study concluded that the failure occured due to fatigue failure and corrosion othe expand pipe of boiler system.