The influence of flank wear, cutting speed and cutting fluid on the surface and sub-surface workhardening produced in an orthogonal planing operation

Abstract This work is a continuation of an investigation into the factors influencing the degree and depth of workhardening produced in the surface layers of an orthogonally cut workpiece. Presently, the influence of tool flank wear land length, cutting speed and cutting fluid are reported for mild steel and aluminium alloy cut by H.S.S. tools at very low speeds; this speed range having been chosen so that the results can be applied to broaching. A mechanism by which the cutting process causes surface workhardening has been proposed previously and has been used to explain the results obtained in the earlier investigations. This model is used again to explain the influence of the cutting variables presently examined. In the last section, the influence on the degree and depth of workhardening of all the cutting variables examined in this and in the previous investigations are listed and predictions are made of the effects to be anticipated as 1. (i) the range of cutting speeds is extended, 2. (ii) restricted rake face tools are used, 3. (iii) cutting edge sharpness is increased and, 4. (iv) cutting tool lubrication is improved.