High strength cemented carbide dies and mandrels for a pilgering machine

In a cold pilgering machine for cold reducing thin walled tubing, the improvement which comprises:

• a pair of roller dies for reducing the cross-sectional size of the tubing, each die being ring-shaped with a central opening for mounting said die on a shaft and having a keyway defined therein adjacent said central opening for receiving a key to secure said die for movement with the shaft, said keyway of said die also providing a timing mark for accurately mounting said die on the shaft, each die having two relief pockets formed in the periphery thereof in circumferentially spaced apart relation with a bridge extending therebetween and a tube-reducing groove formed in the periphery thereof having a tapered configuration and opening at its opposite ends into said respective pockets, an end of one of said pockets being disposed radially outwardly from and aligned with the center of said keyway so as to provide a reference point on said die adjacent the periphery thereof, each die being fabricated from a high strength cemented carbide material composed of tungsten carbide ranging from about 1.5 to about 86 percent by weight and cobalt ranging from about 14 to about 18.5 percent by weight, said carbide material having a minimum Rockwell Hardness "A" ranging from about 84.6 to about 87.7, a density ranging from about 13.70 to 14.00 grams per cubic centimeter, a minimum transverse rupture strength ranging from about 360,000 to about 420,000 psi, an average grain size ranging from 1-6 micrometers at 1500X Mag., a modulus of elasticity ranging from about 75,000,000 to about 78,000,000 psi, and a compressive strength ranging from about 575,000 to about 600,000 psi.