Failure Analysis of Industrial Discharge Hopper Pipe
Keywords:Austenitic Stainless Steel, Transgranular Fracture, Stress Corrosion Cracking
This work presents the detailed investigation and root cause analysis of catastrophic failure of an industrial discharge hopper pipe. The hopper pipe investigated in the present work is made of austenitic stainless steel, 316 grade, a commonly used grade for valves, pipes and heat exchanger tubes. The pipe fractured in transverse direction, leading to the failure of discharge pipe. Visual inspection, dye penetrant test, chemical analysis, microstructural analysis, and fractography analysis were carried out on the failed part and it was concluded that stress corrosion cracking led to the failure of hopper pipe. The pipe constantly being under the exposure of industrial water and the presence of chlorine content in it made it susceptible for stress corrosion cracking. Transgranular fracture was clearly observed in the microstructure of failed sample and spot EDX at the fracture location confirmed the presence of chlorine content. Further, fractography showed striations indicating fatigue loading. The work concluded that stress corrosion cracking as the root cause of failure.