Penelitian Kerusakan pada sebuah Pipa Ketel Uap

Abstract

Failure Investigation on Ruptured Boiler Tube, This paper presents a failure investigation on a ruptured steam boiler tube. This boilertubewas madeoflow carbonsteel, having 76.1 mm outside diameter and 5 mmthickness. Theboiler tube was installed in horizontal position on thefront rear walls ofa steam boiler that was operated at steam pressure and temperature of60 bar and 275C. respectively. The failure investigation was carried out by performing a number of examinations including: macroscopy, metallography, hardness test and scanning electron microscopy (SEM) equipped with EDS (energy dispersive spectroscopy). Results ofthefailure investigationshowed that thefailure on the boiler tube was most likely caused by a short term localized overheating. The overheating temperature was estimated to have reached about 700 - 850°C. This was indicated by the formation of bainite and/or martensite microstructure in some location of the ruptured tube material. Since no any significant scaleformation was observed in the tube internal wall, andalso no anyobvious indication of possible overheating due to a direct burner flame impingement toward the tube outside surface, it was therefore concluded that the occurrence of short term localized overheating on the tube was most probably caused by low water level inthat particular part ofthe boiler tube.