EXPERIMENTAL INVESTIGATION OF THE EFFECT OF TURNING CUTTING PARAMETERS ON SURFACE ROUGHNESS AND MATERIAL’S MICROSTRUCTURE AS A FACTOR OF TURNING SPEED VERSUS FEED RATE

Surface finish in turning can be influenced by a number of factors such as feed rate, work material c haracteristics, work hardness, cutting speed, depth of cut, cutting tool characteristics and use of cutting fluids. In this study, experimental te sts using a lathe CNC machine were conducted in order to investigate the effects of the cutting speed and feed rate, workpiece hardness and depth of cut on metals surface roughness and microstructure in the hard turning, using as a factor the ratio of turning speed versus feed rate. The machining experiments were conducted on three of the widely used material such as AISI-SAE 304 stainless steel, RSt 37-2 construction steel and UNS C38000 brass. In order to analyze the effect of the cutting parameters on the surface, two characterization techniques were employed, namely profilometry and microscopy. The topological structure and roughness of the surface were measured using an optical profilometer and the data obtained was analyzed using dedicated commercial software (Visio Software). Furthermore, the detailed microstructure was examined by a field emission scanning electron microscope (SEM).