A new way of forging crown wheels in counter blow hammer forging has been developed. it is now used for industrial production. The traditional method of manufacturing is upsetting a hot cylindrical billet followed by closed-die forging to a semi-finished product with a thin cylindrical plate in its centre, which is then sheared off and scrapped. Using the new technique a conical tap is formed in the centre allowing a thinner plate. In this way the die pressure, the amount of blows and the weight of the billet can be reduced. The commercial FE-software, FORM2D, has been used for optimising the tool geometry. The analysis was carried out with the conditions that the maximum force, tool pressure and totally required plastic work for the new concept must not exceed the values for the traditional method. For simulating the process, each blow was divided into five incremental steps. The friction coefficient was established by comparing workpiece tshapes obtained from theory and those from full-scale experiments. This was done for the traditional manufacturing route. It was also found that, for this way of manufacturing, only 30percent of the supplied energy were used for plastic deformation. The corresponding value for the new concept was found to be 40percent.
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