AN APPRAISAL AND ANALYSIS OF BOILER PIPES IN AL-MUSAIB ELECTRIC POWER STATION

Abstract

It is hoped in this paper to find out the reasons behind the failure in boiler pipes used in Al-Musaib electric power station. Multi types of mechanical and chemical reasons were found behind the failures of these pipes. Two pipes were selected for this analysis (pipe no. 6 in coil 93) and (pipe no. 7 in coil 48) were they failed selectively. It was found that these pipes of boiler respectively have failed due to overheating as first reasons. In addition, failures are due to hydrogen damage can be considered in failed pipes that lead to form (Fe2O4) phase. The high sulfur containing fire products are also deposited on the outer surface of the tubes making the condensed water around the cracks acidic. In consequence, the examined pipes of boiler are respectively undergoing pitting corrosion. Un-regularity in thickness of failed tubes where measured and gives an indication about how much they eroded. Microstructural observations of the failed and un-failed show quenched microstructure with small amount of carbides present at the grain boundaries