Fatigue in cold-forging dies: tool life analysis

In the present investigation it is shown how the tool life of heavily loade d cold-forging dies can be predicted. Low-cycle fatigue and fatigue crack g rowth testing of the tool materials are used in combination with finite ele ment modelling to obtain predictions of tool lives. In the models the numbe r of forming cycles is calculated first to crack initiation and then during crack growth to fatal failure. An investigation of a critical die insert i n an industrial cold-forging tool as regards the influence of notch radius, the amount and method of pre-stressing and the selected tool material is r eported. (C) 1999 Elsevier Science S.A. All rights reserved.