A study of wear in closed-die counterblow hammer forging

Background: Wear of tools meant for the forging of pinions has been studied. The manufacturing is carried out as counter blow hammer forging in 5 blows. The analysis is restricted to the upper die which is furnished with a conical tap cavity that includes a bootle neck which the material has to pass in order to fill the cavity. Methods: The sliding lengths and the contact contact pressures at different positions of the upper die are evaluated by means of a commercial FEM-code. A wear index is defined assuming proportionality to the die pressure and the sliding length. Results: The wear index is evaluated as the area under a tool pressure-sliding length graph. Conclusion: When the results of the analysis show satisfactory agreement with full-scale experiments, it is clear that wear can be predicted with the defined wear index under controlled geometrical conditions. (C) Munksgaard, 1997.