Fracture analysis of a flow control device used in the petrochemical industry

Abstract

This paper presents a service failure analysis of a steel control device assembled in a petrochemical industry division which resulted in a great fire. The purpose of this analysis was the determination of the reasons that caused fractures in the fixation screws of the body/cover of the valve during operation. The failure caused the leakage of hydrogen (H2) and sulfide gas (H2S), being responsible for an accident in Fortaleza, Brazil. Techniques such as visual inspection, electronic microscopy, optical microscopy, determination of mechanical properties, design analysis by computational simulation and spectrometry were used in this investigation. Several factors influenced the failure mechanism, such as: design failure, environmental cracking, device components out of fatigue and fracture specifications. # 2003 Elsevier Science Ltd. All rights reserved.