Hydrostatic Extrusion is another way to extrude aluminium profiles. Here's how it works. In this process, the chamber is first filled with a fluid which transmits the pressure to the billet. This billet is then extruded using the die. There is no question of friction along the container walls. As the billet is subjected to an uniform hydrostatic pressure, it does not get upset while filling the bore of the container. This effectively translates into the billet having a large length to diameter ratio (even coils of wires can be perfectly extruded) or it may also have irregular cross section. If compared to direct and indirect extrusion, the main difference is that in case of Hydrostatic extrusion there is no direct contact between the container and the billet.

Advantages of Hydrostatic Extrusion

• Owing to the pressurized fluid, the lubrication is very effective
• Extruded product has good surface finish along with dimensional accuracy
• As friction is almost absent, it is quite possible to use dies that has very low semi-cone angle. This minimizes greatly the chance of redundant deformation.
• Minimal friction

Shapes Obtained by Hydrostatic Extrusion process
The shapes obtained by Hydrostatic Extrusion despite coming with a enhanced and better workability is rather simple. One important bottleneck coming in the way is the profile's cross-sectional symmetry. Some typical shapes produced are angles, rods, T-profiles or dumbbells. Other shapes to be produced can single-hollow sections like tubes. The image shows some popular shapes.

Application of Hydrostatic Extrusion Process
Coming to applications, besides aluminium, magnesium is another popular material that is used in the Hydrostatic extrusion process. Actually there are two basic reasons to consider magnesium alloy extruded profiles manufactured by Hydrostatic Extrusion process. One is the products that calls for medium strength combined with high ductility, while the other calls for high strength. Some of the critical industry applications of Hydrostatic extrusions include automotive, aviation etc.


Typical parts for these industries include:

• Body and hang-on parts
• Aircraft Interior structural parts
• Tram Interior fittings
• Bicycle Front-fork interior parts

Use of Magnesium in Hydrostatic Extrusion It is a fact that magnesium cast products have achieved for themselves a reputed name when it comes to industrial lightweight applications. Today the focus is now on to develop wrought products. Such development can lead the way for achieving a more broader variety of shapes along with ensuring that more improved magnesium alloy properties are put to good use. To develop such a shaping technology technologically superior Hydrostatic Extrusion is showing the path. However on the down side it does not score so much over direct and indirect extrusion processes because of limited resources (both technical and economical associated with it). In fact that is the reason why extrusion is not so popular for Magnesium alloys. The following image is of a typical tube made of Hydrostatic Extrusion: