Effect of cutting speed and tool rake angle on residual stress distribution in machining 2024-T351 aluminium alloy — unlubricated conditions

The residual stress distribution in the machining of 2024-T351 aluminium alloy was measured using an electrolytic etching technique. Ring-shape specimens were machined under unlubricated orthogonal conditions with high-speed steel tools having rake angles of 10, 15, 20 and 25° at cutting speeds ranging between 0.5 and 1.25 m sec^–1. The results of the investigation show that the residual stresses are compressive at the machined surface and decrease with depth beneath the machined surface. The maximum (near-surface) residual stress and the depth of the severely stressed region increase with an increase in the cutting speed. There seems to be little change in the residual stress distribution due to a change in the rake angle. The results are interpreted in terms of the variations in the amount of surface-region deformation produced by changes in cutting conditions.