Aluminum is a distinctive element with properties that make it especially valuable in applications requiring low weight, corrosion resistance, strength, and conductivity. Through extrusion, it can have any desired cross-section, which can include a variety of practical functionalities. This process is also less costly than molding or casting and can be completed much more quickly.
This article will go over the basics of aluminum extrusion, including its definition, process, and applications.
What Is Aluminum Extrusion?
Aluminum extrusion is a technique for transforming aluminum billets into objects with a defined cross-sectional profile. This process is accomplished by forcing the heated alloy material through a die.
Extrusion allows for the creation of both standard and complex shapes, which you can categorize into the following:
- Solid: no enclosed openings or voids (rod, beam, or angle)
- Hollow: with one or more openings or voids (square or rectangular tube)
- Semi-hollow: with partially enclosed openings or voids (“C” channels with narrow gaps)
The Aluminum Extrusion Process
Extrusion typically occurs in direct or indirect presses with varying power levels. The basic process can be divided into five steps that manufacturers can adjust depending on the customer’s requirements.
Preheating the Steel Die and Aluminum Billet
The steel die is preheated to 450-500 ℃ before loading into the press to maximize its life and ensure even metal flow. Then, the billet — a solid, cylindrical block of aluminum alloy — is preheated to 400-500 ℃ to make it malleable enough for extrusion.
Loading the Billet Into the Extrusion Press Container
After preheating the billet, a lubricant or release agent is applied to it before being mechanically transferred to the extrusion press. The release agent is also used in the extrusion ram to prevent it from sticking to the billet.
Extruding the Heated Aluminum Billet
The heated aluminum billet is pushed through the tool openings, which are adjustable to create different shapes and sizes. In addition, liquid or gaseous nitrogen is incorporated and allowed to flow through the die sections to prevent the formation of oxides. This method produces an inert atmosphere and extends the die’s life.
Cooling the Extruded Component
Quick cooling follows the extrusion process, where the bars are subjected to a water bath to ensure uniform quenching of the heated aluminum. Moreover, the cooling process is carried out without delays to prevent material deformations.
Cutting and Stretching the Bar
The extruded bars are immediately cut to the specified interphase length after quenching. A puller then grabs the cut bars and places them on the runout table before going through a strengthening process. This stretches the bars and removes the internal tension to maintain their mechanical properties.
Applications of Custom Aluminum Extrusion
The following are some of the applications and industries that use the aluminum extrusion technique in their operations:
Architecture and Construction
Aluminum extrusions are used in various architecture and construction applications — from railings and ledges to building facades and bleachers. They are also ideal for making canopies with light but strong structures. In addition, extruded aluminum components are utilized in ladders, walls, and suspended ceilings.
Due to their excellent conductivity, extruded aluminum is frequently used for busbars and related electrical equipment. One example is the aluminum extruded with fins which is an ideal lightweight radiator or heat exchanger that can easily be mounted and colored. They are also applied in lighting applications and solar panel support structures.
Extruded bars and profiles are one of the most preferred materials for equipment like workbenches, inspection tables, and carts because they are lightweight, easy to cut, and cost-effective. They also have the added feature of being expandable, which means that if equipment needs to be modified, it can be done quickly.
Aluminum extrusions are used to manufacture products such as panels, engine blocks, and vehicle chassis. Their high strength-to-weight ratio enables the production of lightweight components, resulting in lighter vehicles. They also provide resistance to the environmental impact of moisture, corrosive forces from road salt, and temperature.
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