Análise de falha em tubulação de equalizador de aço ASTM A178 grau a de caldeira aquatubular

Abstract

Failures in industrial boiler piping are a recurring issue due to extreme operating conditions such as high temperatures and pressures, leading to substantial maintenance costs, operational interruptions, and safety hazards. This study investigates the root causes of failure in an equalizer pipe of a water-tube boiler, fabricated from ASTM A178 Grade A steel, by analyzing the underlying mechanisms and proposing preventive measures. The research involved macroscopic examinations, hardness testing, and both microstructural and chemical analyses using Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS), along with an evaluation of internal deposits and a comparison of the chemical composition against normative specifications. The results indicated that the rupture occurred as a result of long-term overheating, which was exacerbated by thick internal deposits that compromised heat exchange efficiency, leading to the formation of aligned graphite structures and creep voids that contributed to the failure. Furthermore, the analyses revealed that operational deficiencies in water treatment control allowed the accumulation of scale, thereby intensifying the thermal degradation process. To prevent similar failures in the future, periodic inspections of the piping to detect microstructural degradation, videoscopic analysis of scale deposits, and a review of water treatment procedures are recommended.