Failure analysis of AISI 304 stainless steel shaft

In this paper, we present a failure analysis methodology of a structural component using a conventional 14-step failure analysis approach. This failure analysis methodology focused on observation, information gathering, preliminary visual examination and record keeping, nondestructive testing, mechanical testing, selecting/preservation of fracture surfaces, macroscopic examinations, microscopic examinations, metallography, failure mechanism determination, chemical analysis, mechanical failure analysis, testing under simulated service conditions, and final analysis and report. The application of this methodology is demonstrated in the failure analysis of a mixer unit shaft made of AISI 304 stainless steel. Using this failure analysis approach, we pinpointed the primary mode of failure and developed a means of circumventing this type of failure in the future. The results show that the steel shaft failed due to intergranular stress cracking (sensitization during welding) at the heat affected zones (weld plugs).