What is aluminum extrusion?
Extrusion is a process done to shape materials, aluminum extrusion is the method of extruding aluminum to obtain a certain shape. It helps in the elongation of the metal.
Steps of extruding aluminum –
- Heating of billets
- After heating the billet is transferred to the loader and lubricated with smut.
- After this, the billet is further transferred to the cradle.
- The billet is forced to push inside the container by application of pressure.
- The pressure causes the billet to crush against the die until it has complete wall contact.
- Liquid nitrogen cools the die creating an inert atmosphere.
- The billet begins to mold and squeeze.
- Recording of the exit temperature to maintain press speed.
- Expulsion of extrusion guiding the metal down the runout.
- The remaining unused billet which is the remainder of the whole process is discarded. Another billet is loaded continuing the cycle of extrusion.
- When the desired size is obtained the extrusion is cut.
- Transfer of the metal from run to the cooling table.
- Moved to a stretcher from the cooling table to straighten and harden the aluminum.
- The cutting process with a saw to obtain the adequate/required size and shape.
- Heat treatment to harden the metal.
Types of extrusion –
Direct extrusion – It is also known as forwarding extrusion.
Indirect extrusion – It is also called backward extrusion.
Hot extrusion – This process is the most common method done with an increase in temperature which helps to shape up the material.
Cold extrusion – It is used at a lower temperature which is apt for the extrusion process to begin. It is also done by the process of striking or slug.
Warm extrusion – It is done to provide ductility to the material. It is carried out at normal room temperature which is below the recrystallization temperature of the material.
Aluminum is the most commonly extruded metal.
Let us understand some terms related to the extrusion process –
- What is the extrusion ratio? The extrusion ratio is the ratio of the area of billet to the ratio of the area of the shape.
- What is the tongue ratio? It is the gap width Vs the gap depth
- What is the factor? The factor is the ratio of shape perimeter: weight per meter.
- What is an alloy? Chemical components added to pure aluminum to increase its strength and enhance its other properties
- What is Tolerance? It is a limit of variation of production of the product
The aluminum extrusion process with the help of a powerful hydraulic press is made it easier to attain the desired shape and size.
What is corrosion or rusting?
Corrosion or rusting is a condition that occurs when the metal starts to oxidize. It is a very bad condition which causes deterioration and finally collapse of the material. This could lead to high damage and extreme conditioned if gone unnoticed. To prevent corrosion metals must be lubricated and if not the corrosion would also spread to the attached other metals.
Aluminum extrusion is very beneficial as it adds lubricant and also strengthens the metal which makes the metal-free from corrosion or rusting.