Hydrostatic Extrusion
From Wikipedia, the free encyclopedia
Hydrostatic extrusion is the process by which a billet of material, usually a metal is formed into an extrudate of smaller cross-sectional area. This is achieved by applying high pressure from a hydraulic ram to the billet through the medium of a liquid, and hence the notion of 'hydrostatic' extrusion. The pressurised medium then forces the billet through a specially shaped die and the extruded product emerges from the exit end of the die.
The process must be carried out in a sealed cylinder to contain the hydrostatic medium. The speed of the ram and required extrusion pressure are dependent on the nature of the billet material (stiffness, abrasiveness,density and other physical properties) and the reduction ratio of the cross-sectional area of the billet and the die aperture. Due to frictional and other effects between the billet and the die, heat is generated during extrusion. This can be reduced by means of lubrication.
