Effect of putrefied quenching oil on the transformation behaviour of railway spring steel.

Bogie springs are safety critical components that also provide a smooth ride to the rail vehicle by absorbing vibrations and shock loads during the movement of the train. This study investigates the cause of premature failure of springs. These springs were manufactured from a high strength steel grade, SAE J404 grade 5160. The investigation process focused on heat treatment processes and failure mechanisms. Oil properties were also scrutinised by conducting quench tests. The overall findings of the investigation highlighted the detrimental effect of a degraded quenching oil on the fatigue life of the springs. Implementing certain measures from these findings will increase the spring lifespan and contribute towards safe operation of the trains.