Effect of the Electro-Discharge Machined Surface on the Mechanical Properties

On the fatigue strength of cemented carbide

Abstract

The surface defects generated by EDM of cemented carbide give a harmful influence to prolongation of die life, The effect of surface defects on the transverse rupture strength was studied already, Evaluating the material strength, the fatigue strength is also important, In this paper, the relation is investigated between the fatigue strength of cemented carbide and the machining condition of EDM. Moreover, the fatigue life distribution is obtained from the statistical analysis, The results are as follows:
(1) Cemented carbide machined by EDM clearly shows a fatigue behaviour and has a fatigue limit. It indicates a considerable decrease of fatigue limit comparing with that of the ground specimen.
(2) The fatigue limit is shown by a curve with both minimum and maximum value as the pulse duration increases.
(3) The fatigue life scatters largely and its distribution can be explained by Weibull's equation.