In the present investigation it is shown how the tool life of heavily loaded cold-forging dies can be predicted. Low-cycle fatigue and fatigue crack growth testing of the tool materials are used in combination with finite element modelling to obtain predictions of tool lives. In the models the number of forming cycles is calculated first to crack initiation and then during crack growth to fatal failure. An investigation of a critical die insert in 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 reported. (C) 1999 Elsevier Science S.A. All rights reserved.
- life analysis