Investigation of the Shear Friction in Aluminum Alloy Extrusion.

Starting from earlier measurements of the direct extrusion of tubes, a working hypothesis in the form of a maximum curve is proposed which underlies the dependence of shear friction on the specific extrusion pressure. In tests on prestressed aluminum ingots, the physical reality of this dependence of the shearing friction was shown. Qualitative differences in the mandrel loading, specific to the process, are deduced for the direct and indirect extrusion of aluminum alloys are discussed; the limits and possibilities of determination of the frictional force are discussed critically.