Azin Ahmadi - Researcher, Industrial Environmental Protection Division, Research Institute of Petroleum Industry (RIPI), Tehran, Iran
Akram Nouri Delavar - Researcher, Industrial Environmental Protection Division, Research Institute of Petroleum Industry (RIPI), Tehran, Iran
Amir Pasha - Researcher, Industrial Environmental Protection Division, Research Institute of Petroleum Industry (RIPI), Tehran, Iran
Mohammad Shayegani Akmal - Researcher, Industrial Environmental Protection Division, Research Institute of Petroleum Industry (RIPI), Tehran, Iran

to transfer power of an electromotor to various equipment. The most common material shaft for electromotor is AISI 1045 carbon steel. In this study failure causes of an electromotor shaft was investigated. Chemical and metallographic analysis, hardness measurements and scanning electron microscopy (SEM) were performed to determine causes of the failure. The microstructure evaluations showed ferritic-pearlitic microstructure in the area behind the fracture surface was heterogeneous. Fracture surface evaluation by SEM revealed that the fatigue was the failure mechanism of the shaft. However, the value of design stress was lower than the calculated stress fatigue limit. According to Miner equation, the percentage of the consumed fatigue life of the shaft in the first two years of its operation was greater than that in the second two years. It was concluded that the shaft failure occurred due to termination of its fatigue life.

Microstructure, AISI 1045, Fatigue, Striations