Aluminum Pipe

Step 1: From Extrusion Die to Extrusion Press
Circular dies are generally made from H13 steel. When a suitable die is available, it is retrieved from storage. Prior heating of the die to 450-500°C is essential, prolonging its life and ensuring stable metal flow during extrusion. The preheated die then fits into the extrusion press.

Step 2: Pre-Extrusion Heating of Aluminum Billets
Initially, a cylindrical aluminum alloy block, or billet, is cut from a larger alloy batch. This billet goes into an oven, heated between 400-500°C. This treatment softens the billet for extrusion without liquefying it.

Step 3: Transferring the Billet to the Extrusion Press
The preheated billet is methodically transferred to the extrusion press. A lubricating agent is applied to both the billet and the press ram to prevent them from adhering.

Step 4: Pressing the Billet into the Chamber
The softened billet enters the extrusion press, where a hydraulic ram imposes 15,000 tons of force. This extraordinary pressure pushes the billet deeper into the chamber, making it expand and adapt to the chamber walls.

Step 5: Formation of Extruded Solids
Once the metal fills the chamber, it meets the extrusion die under pressure. This constriction allows the aluminum to exit only through the die apertures, producing a finished pipe or tube.

Step 6: Extrusion and Quenching Process
Upon exiting the die, a puller maneuvers the extrusion along the run-out table, keeping pace with its press exit speed. Concurrently, it's "quenched" or cooled continuously using a fan or a water bath.

Step 7: Cutting Extrusions to Table Length
When the extrusion reaches the table's end, a heated saw cuts it to separate it from the extrusion process. Temperature plays an integral role throughout. Even after rapid cooling post-press, the extrusion remains warm, without fully cooling.

Step 8: Cooling the Extrusions
The cut extrusions transfer to a cooling table, permitting them to return to room temperature. Once cooled, the subsequent stage involves stretching the tubes or pipes.

Step 9: Stretcher Alignment
With natural twists in pipes or tubes, alignment is obligatory. Using a stretcher, each piece is clamped and stretched until perfectly straight and compliant.

Step 10: Cutting Extrusions to Specific Lengths
Once aligned and work-hardened, extrusions shift to the saw table for cutting into specific lengths, generally between 8-21 feet (2.4-6.4 meters). They initially exhibit a T4 temper. Subsequent oven aging may further treat them to attain T6 or T5 temper.