| 摘要 |
An improved cooling system is provided in a piercing mandrel used in extruding tubular material made of metals having extruding temperatures above the annealing temperature of H13 tool steel such as brass, copper and the like. The piercing mandrel has a replaceable tip fitted on the end of the stem portion for the mandrel. A cooling channel system is provided at the distal end of the stem and comprises a disperser for dispersing cooling fluid in equi-distant, multi-radial directions as the cooling fluid flows out of the stem distal end. An annular channel is provided at the perimeter of the mating faces of the bore in the tip and the stem distal end and which is in communication with the disperser to direct radially cooling fluid annularly of the perimeter of the mating faces at the stem distal end. The cooling channel system further comprises about the perimeter of the stem distal end a plurality of equi-distant, longitudinally directed channels which are in communication with the annular channel. Cooling fluid flows from the annular channel longitudinally of the tip along the longitudinal channels. The stem distal end has a cooling fluid outlet device for collecting cooling fluid and directing spent cooling fluid outwardly along the stem.
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