Fatigue life is one of the most important specifications for machined components. There are various machining parameters, which have an effect on fatigue life. This paper investigates the effect of these parameters on fatigue life of steel components with the effect of machined surface finish. For this purpose, steel specimens were machined on a CNC lathe and then subjected to fatigue test. These specimens were machined using different cutting speeds, different feed rates, different depth of cut, and different tool nose radius. Measurements of surface finish were carried out for all machined specimens before fatigue test using telysurf. The fatigue tests were carried out using Four-point rotating bending test on a machine. The results of investigation show that, the surface finish after turning operations with the combinations of cutting conditions that were used during turning have great effects on fatigue life. The results also show that, longer fatigue lives for the machined specimens can be obtained by applying cutting speed of 25.13 m/min., low feed rate (0.1 to 0.2 mm/rev.) and small depth of cut (0.1 to 0.15 mm.) for tool nose radius of 0.4mm. |
