THE INFLUENCE OF CUTTING EDGE RADIUS, CUTTING SPEED AND FEED ON SURFACE ROUGHNESS AND MICROHARDNESS IN MACHINING STAINLESS STEEL

The article investigates the impact of cutting edge radius and cutting parameters on the surface roughness and microhardness of austenitic stainless steel (AISI 321) during external turning. Experiment was performed for cemented carbide cutting inserts with cutting edge radii of 5 µm, 18 µm, and 50 µm. Cutting edge with radius size of 5 µm had sharp cutting edges containing small chamfers and burrs of approximately 5 µm in size. Cutting speed and feed were varied in the experiment. Surface roughness parameters (Ra, Rz) and microhardness (HV) were measured. The results indicate that feed and cutting edge radius significantly influence surface roughness, while cutting speed has minimal effect. Microhardness increases with larger cutting edge radii due to strain hardening caused by material deformation beneath the cutting tool. ANOVA analysis confirmed that the interaction between feed and cutting edge radius plays a crucial role in determining the final surface quality. These findings provide insights into optimizing machining parameters for improved surface integrity and mechanical properties in stainless steel turning.