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Aluminum Extrusion Process

Aluminum Extrusion

Aluminum extrusion involves the transformation of aluminum alloy to a fixed cross-sectional profile. Aluminum is pushed through a die and it comes out of an opening into a particular shape in a solid form. We can take an example of a toothpaste tube the way it is pressed and pushed out where the mouth of the tube acts as a die and the paste comes out in a cylindrical shape. Aluminum extrusion works the same way.

Shapes that can be Extruded

Aluminum can be extruded in three forms or shapes such as

  • solid bars or rods, beams, and angles
  • Hollow sections such as tubes of different shapes round, square and rectangular
  • Semi-hollow shapes such as channels

Extrusion is required for several applications including automobile, electronics, architectural, construction and aerospace, etc. Several complex shapes can be extruded for different applications.

Aluminum Extrusion Process

It involves 10 stages are given below:

1.     Die Preparation

The first stage is preheating the die at a temperature ranging from 450 to 500  in order to ensure proper flow of the molten metal.

2.     Preheat Aluminum Billet

A solid block of aluminum known as a billet which is preheated at temperature 450 to 500  to make it malleable.

3.     Transfer of Billet to Extrusion Press

The extrusion press is then greased before adding the billet in order to prevent it from sticking to the surface of the extrusion process and ensuring smooth flow.

4.     Material pushed to the Container

The preheated billet is pushed to the container by applying pressure of around 15000 tons with the help of a hydraulic ram.

5.     Material comes out of the Die

When pressure is applied continuously, the aluminum comes out through the opening into the die turning into the shape of the die.

6.     The Extruded Material is then Quenched

When it comes out of the die, it is gripped and placed on the runout table and quenched with the help of water.

7.     Extruded Material is Trimmed

The next stage involves trimming the extruded aluminum to the length of the table and at this stage it is not fully cooled down.

8.     Extruded Material Cooled Down

At this stage, it is placed on the runout tables to cool down until it reaches room temperature.

9.     Alignment

If there are any imperfections that need to be straightened it is pulled with the help of a stretcher and stretched and straightened.

10.  Cut to Length

This step involves cutting the extruded aluminum to the length required by the client or customers’ requirement and transferred to an aging oven for tempering.

Steps After Extrusion

After extrusion the next steps involve Heat treatment of extruded Aluminum, Surface Finishing and Fabrication:

  • Heat Treatment

Heat treatment helps in improving the tensile strength and yield strength of the extruded.

  • Surface Finishing

This step involves procedures that help in keeping the metal safe from corrosion and includes anodizing, sublimation, painting, sandblasting, or powder coating.

  • Fabrication

This step involves punching drilling, cutting, and machining as per the required dimensions.