4. Concluding remarks and future research perspective SLM steels are exposed to dynamic loading condition in many applications; thus, understanding their fatigue behaviour and characteristics is necessary to estimate their fatigue life under such loading conditions. However, there are few studies dealing with the fatigue properties of SLM steels in the literature. In addition, these studies are not organized to be used for the development of numerical models and equations to predict the fatigue life. Thus, fatigue behaviour of various SLM steels demand some comprehensive and organized further studies to be understood.