Failure analysis in the tube of the refrigeration system of a reheating furnace

Abstract This work aimed to analyze a failure that occurred prematurely in an ASTM SS Grade 70 steel tube in the cooling system of a reheating furnace. The following techniques were used: visual inspection, optical microscopy (OM), scanning electron microscopy (SEM), chemical analysis by energy dispersive spectroscopy (EDS), Vickers microhardness (HV) and measurements and chemical analysis by optical emission spectrometry (OES). It was concluded that the failure was caused by a drastic corrosion process, due to microstructural changes resulting from the loss of the refractory coating.