Machinability of Free-cutting Leaded Steels

Abstract

The machinability of free-cutting leaded steel was investigated from the view-point of tool life, surface finish, cutting force and chip formation. Orthogonal and conventional cutting tests were performed for nine grades of leaded steel and four grades of non-leaded steel in order to determine the effect of including lead in steel. The addition of lead to steel was found effective in improving the machinability. The cutting mechanism of free-cutting leaded steels was analysed based upon the flow region concept. The effects of depth of cut and lead content on the cutting process were discussed. It was found that a smoother shear deformation occurs in the cutting process for leaded steels than for non-leaded steels, and hence the inclusion of lead in steels improves machinability.