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