Machinability Characteristics of Heat Treated Aladja St60-2 Structural Steel

Abstract

Normalised and quenched and tempered specimens of ST60-2 structural steel procured from Aladja developed fine pearlite microstructures that improved its machinability and accompanied by good surface finish at various cutting speeds under soluble oil lubrication condition. While the resulting good surface finish in the low-speed range could be attributed to the effectiveness of the soluble oil that prevented the built-up edge formation, the poor surface finish obtained in the intermediate cutting speed range could be linked to the badly broken chips and the observed built-up edge formation in the machining process. However, the improved surface finish at high cutting speed could be attributed to the total disappearance of the built-up edge. From the standpoint of surface finish, better cutting conditions were established based on the prevailing lower tool-face friction being assessed by the observed curl chip formation characteristics in the machining operation.