The Impact of Prestressed die Construction with Cemented Carbide Insert on Stress Distribution During Extrusion

Abstract

An important parameter for optimizing tool life is the introduction of a precompression stress in the die insert through the use of the compression ring. The tests were carried out for a die with a cemented carbide insert. Three die construction solutions were used in the tests. They differ by the ratio of the wall thickness of the die insert to the wall thickness of the compression ring g m /g p = (0.57; 1; 1.75) while maintaining a constant tool diameter. All construction solutions using cemented carbide insert were analysed for three values of mounting interference amounting to d = (0.004; 0.008; 0.016) mm. On the basis of the results obtained, the degree of impact of the parameters examined (the interference value d and the ratio g m /g p ) on the distribution and level of circumferential stress in a die compressed by a single ring using a cemented carbide insert were determined. It was shown that the size of the interference and the quotient (g m /g p ) had the great impact on the reduction of working stresses in the die insert.