| 摘要 |
Apparatus for the continuous extrusion of metals in which feed is introduced into two (or more) spaced apart circumferential grooves 4 in a rotating wheel 2 (or rotating wheels) to contact an arcuate shoe portion 8 and abutments extending into the grooves. The feed is constrained by the abutments to flow through frusto-conical exit apertures 10 in the shoe portion 8 to a chamber 6 and is extruded as relatively thin-walled, large cross-section, product. The exit apertures 10 have cone angles in the range 5 DEG - 45 DEG . Mixer plates 14 are profiled to distribute flow evenly from the apertures 10 to around the die opening 30. An extrusion die body 18 for cylindrical extrusions is located and axially centred by set screws 122. Where an even number of grooves 4 are utilised, an extrusion mandrel 12 may be secured to the shoe portion 8 by a bolt 22 positioned centrally of the grooves. Lubricant or oxidation inhibiting fluids may be injected internally of the extruded product through a passage 36, 38 extending through the shoe portion 8 and the bolt 22. In another embodiment, the chamber 6 is also of divergent frusto-conical form having a cone angle corresponding to that of the apertures 10, thereby enabling the extrusion of even larger cross-section products. The frusto-conical form may be of elliptical cross-section to achieve a requisite divergence or to accord with the configuration of the die orifice. By providing spaced apart grooves 4 and apertures 10 diverging frusto-conically it is possible to extrude products of relatively large cross-section since the volume feed rate is enhanced and the distance travelled by the material from the grooves 4 to the die orifice 30 is reduced, thereby reducing friction losses and the likelihood of discontinuities in the extrudate arising. |
