Analysis of a Fractured Threaded Fastener

During an outage at a nuclear power plant, a fragment of a threaded ASTM A193 B7 fastener associated with a diesel engine was discovered. The fastener fragment was lodged in a fastener hole and had to be drilled out to be removed. Examination of the drilled out fragment showed remnants of the fracture surface associated with the original failure. Analysis of the fracture surface indicated high cycle fatigue initiation from multiple origins within the thread roots. This presentation will give an overview of the failure analysis performed on the fastener.