Experimental Investigation on the Machinability Response of AISI 4340 Steel in Turning

English (OpenAlex)

In this study, the machinability behavior of AISI 4340 was experimentally investigated considering surface roughness and forces. TiAlN-coated CCMT 09T308 type carbide cutting inserts were used for cutting operations. Three basic cutting parameters were considered in the experimental study: feed (0.15–0.30 mm/rev), depth of cut (0.20–0.40 mm), and speed (120–180 m/min). A total of 8 experiments were conducted according to a full factorial experimental design. Forces were measured with a dynamometer during machining, and surface roughness values were determined after machining using a portable roughness measuring device. The results showed that the most influential parameter on roughness was the feed, followed by speed as the second most influential factor. The effect of depth of cut on roughness was found to be quite limited. The most dominant parameter affecting forces is cutting depth, followed by feed rate. Optimum machining conditions were observed with 0.15 mm/rev, 0.20 mm, 180 m/min, aiming to minimize both performance indicators. The findings indicate that in turning AISI 4340 steel, surface quality is primarily dependent on the feed rate, while cutting forces depend on the chip cross-sectional area.