Effects of cutting parameters and tool nose radius on surface roughness and work hardening during dry turning Inconel 718

The performance of a machined part is significantly influenced by its various surface integrity characteristics. However, the surface integrity of a machined part depends on the material and the cutting conditions employed. The present work investigates the effects of the cutting speed, the feed rate, and the tool nose radius on machined surface roughness, microhardness, and degree of work hardening of Inconel 718. Dry turning tests are performed using three different cutting speeds, three different feed rates, and two cutting tools with different nose radius. The results indicate that the feed rate and the tool nose radius have dominant effect on the machined surface roughness, whereas no clear tendency between the cutting speed and the surface roughness can be found. The results also indicate that the degree of work hardening is strengthened as the cutting speed and the feed rate increase. However, the degree of work hardening tends to be reduced significantly when larger tool nose radius is employed. Through the analysis of the results in the present work, the mechanism of the machined surface roughness and the degree of work hardening of dry turning Inconel 718 can be better understood. This can be contributed to investigate the effect of surface integrity on fatigue life of a machined part.