Basic Knowledge and Process Flow of Aluminum Extrusion
Published Time:
2026-08-14
Author:
Guantian Aluminum
The composition of aluminum alloys varies according to the types and contents of alloying elements added to aluminum. Aluminum ingots serve as raw materials for the aluminum extrusion process. The tool used to produce aluminum profiles with specific cross-sections is known as an aluminum extrusion die. Made of steel, the die contains one or multiple openings shaped to match the required profile.
The composition of aluminum alloys varies according to the types and contents of alloying elements added to aluminum. Aluminum ingots serve as raw materials for the aluminum extrusion process. The tool used to produce aluminum profiles with specific cross-sections is known as an aluminum extrusion die. Made of steel, the die contains one or multiple openings shaped to match the required profile.
Heat plays a vital role in the aluminum extrusion process. Temperature monitoring throughout the whole procedure is critical to guarantee target properties such as tensile strength and yield strength, and it also affects the surface finish of finished profiles.
The aluminum extrusion process starts with heating aluminum ingots or billets to 400–480°C (750–900°F). The aluminum alloy remains solid but becomes ductile. Aluminum will not glow after heating, and its appearance stays nearly unchanged whether hot or cold.
The heated billet is transferred into the extrusion container. Hydraulic pressure is applied axially to the billet, pushing aluminum to fill the container. Rising internal pressure forces the aluminum alloy to flow through the openings of the extrusion die. A continuous aluminum shape with consistent cross-section emerges from the other side of the die, namely the extruded aluminum profile.
Extrusion speed is determined by component size, profile complexity, wall thickness, aluminum alloy grade and the number of cavities or openings on the extrusion die. A puller, a jaw-type mechanical device clamping the material, guides the profile and stretches it along the extrusion table as it exits the die.
When the aluminum profile comes out from the die, its temperature ranges from 510°C to 550°C. Cooling is carried out by fans, water spray or full water quenching. The aluminum must be cooled at a specified rate to achieve required alloy properties. Temperature readings are taken repeatedly during production to hit target parameters.
Long extruded profiles are mechanically transported to the cooling table until they reach room temperature. The cooled profiles then undergo stretching, a mechanical treatment to straighten the profiles. Afterwards, the stretched profiles are cut into lengths generally ranging from 6 to 30 feet according to customer orders.
The phenomenon that the strength and hardness of quenched aluminum alloys rise obviously over time is defined as aging. The heat treatment stage refers to artificial aging for aluminum profiles to obtain target hardness. Aging can occur naturally at room temperature, known as natural aging. It can also proceed within a temperature range above room temperature such as 100–200°C, which is artificial aging. Profiles are generally kept in aging furnaces for up to 8 hours. Artificial aging greatly shortens processing cycles. After aging, the profiles can be delivered to customers directly or subjected to further processing including CNC machining and other mechanical operations.
