I dont have any doubt that mechanical properties from Al extruded tubes are better than pressure die casting Al tube.

The extrusion process give the material improve characteristics by the plastic deformation.

When the ratio between billet area and tube area is increase, better are the mechanical properties improve.

Also, extrusion will avoid casting defects. Moreover, one can only cast relatively short tubes, as casting is normally a batch process. Extrusion, being a semi-continuous process, enables much longer tubes, and better surface finish.

Im 100% agree with Mr Browne ideas.

Also, extrusion creates grains elongated in the direction of extrusion. That causes material properties difference between longitudinal and transverse directions.

Extruded products are called as wrought products , and its a well know fact that a wrought structure is superior to cast structure. Pores getting closed down, homogeneity, anisotropy (properties greater in the direction of extrusion) & other metallurgical factors makes a wrought products superior .

If we consider for HPDC or PDC can  we expect mechanical properties equivalent to Extruded products.

HPDC & PDC are certainly better than conventional casting when it comes to mechanical properties , but not as much as a wrought product, especially when you are working on Aluminium.

Wrought materials are typically better and lack defects inherent in casting processes.

Have you considered other near net shape proceses? MIM? Additive? PM?

Dear Pranav Shinde,

As far as I can see, the 0.2% yield strengths of common Al extrusion alloys, e.g. from the 6000-series, can equal those of Al alloys used for pressure die casting, albeit the latter show in general lower values for fracture strain. The foregoing implies that for optimizing the resistance against torsion one has to invoke the cross section and length of the tube as well.  Then, it might appear that the desired cross section/length combination can only be obtained by pressure die casting.Your question shows a typical example of the fact that the product design can be of equal importance for the final mechanical product properties.