ALUMINUM EXTRUSIONS AND PROFILES

√ What Is Aluminum Extrusion?
Aluminum extrusion is a manufacturing process that shapes aluminum by forcing it through a die with a specific cross-section. The die opening determines the profile shape - solid, hollow, or complex - which allows for a wide range of industrial and architectural applications.

√ Step-by-Step Detailed Process:
1. Designing & Preparing the Die
Before extrusion begins, a precision die is created from hardened tool steel (often H13 or similar). The die’s opening matches the desired final profile shape. Dies are often preheated to around 450–500 °C to prevent thermal shock and ensure smooth metal flow.

2. Billet Preparation
The raw material used is a solid cylindrical aluminum billet — typically a specific alloy (e.g., 6063, 6061, 6082…. etc.) chosen based on required mechanical properties. The billet is cut to length and preheated to about 400–500 °C to soften it, making it malleable without melting.

3. Loading & Lubrication
The heated billet is moved into the extrusion press container. A lubricant or release agent (such as graphite or oil) is applied between the billet and press components to reduce friction and ensure uniform extrusion.

4.Extrusion (Pressing Through the Die)
A hydraulic ram applies enormous force — up to thousands of tons of pressure — to push the billet through the container and into the die. As the aluminum flows through the die opening, it takes the cross-sectional shape of the die and emerges as a continuous profile.

5.Immediate Cooling (Quenching)
As the newly formed profile exits the die, it is guided along a runout table by a puller. Cooling begins immediately using air jets, fans, or water spray. This rapid cooling (quenching) helps lock in the profile’s shape and mechanical properties.

6.Cutting to Table Length
Once enough profile has been extruded to span the runout table, a hot saw cuts the extrusion to a basic “table length” for easier handling.

7.Room-Temperature Cooling
After hot cutting, the profiles are moved to a cooling bed rack where they are allowed to come down to room temperature naturally.

8.Stretching and Straightening
Some twist or curvature occurs during extrusion and cooling. To correct this, profiles are fed into a stretching machine that clamps both ends and gently pulls them straight. Stretching also relieves internal stresses, improving dimensional stability.

9.Finishing Cutting
Once straightened and fully cooled, profiles are cut to final customer lengths — often specified in meters or feet — using precision saws.

10.Aging and Heat Treatment
Many aluminum alloys require aging or heat treatment to enhance strength and hardness.T5 and T6 tempers are common: profiles are heated under controlled conditions to achieve desired mechanical properties.

11.Secondary Operations
After extrusion, profiles often undergo further processes depending on application:
• Surface finishing (anodizing, powder coating, painting)
• Machining or drilling
• Assembly or fabrication

√ Why This Process Is Widely Used?
Aluminum extrusion offers:
• High precision and uniformity of complex shapes.
• Efficient production of long profiles.
• Excellent material properties relative to weight.
• Flexibility for downstream finishing and machining.
It’s used in construction, transportation, electronics, aerospace, and many other sectors.

√ Characteristics of Industrial Aluminum Profiles/Extrusions
Industrial aluminum Profiles, also called Industrial aluminum Extrusions or Industrial aluminum Alloy Profiles, are profiles of aluminum shaped by the process of forcing it to flow through a shaped opening in a predesigned die. The extruded material emerges as an elongated piece with the same profile as the die opening. Depending on the final application of the aluminum profile or extrusion, the alloy used in the extrusion process varies. These various alloys have differing properties mainly characterized by the following 6 aspects:

Due to the nature of aluminum many customers are concerned by the materials hardness when buying an industrial aluminum profile. Hardening of aluminum profiles is achieved by “heat treatment” as opposed to flat rolled products which generally achieve greater hardness or strength by a cold working/rolling process. It is important to note that an aluminum extrusions hardness is directly related to the chemical composition of the alloy. Alloy 7××× series contains the highest achievable hardness followed by alloy 2××× series, alloy 4××× series, alloy 6××× series, alloy 5××× series, alloy 3××× series and finally alloy 1××× series respectively.

Strength is an important factor when considering product design. When aluminum alloy profiles are used as industrial components, the appropriate alloy should be selected according to the structural integrity required. The strength of pure aluminum (1××× series) is the lowest, while that of heat-treated alloys of the 2××× series and 7××× series are the highest.

Corrosion resistance of industrial aluminum profiles includes chemical corrosion and stress corrosion amongst others. Generally speaking, alloy 1××× series of pure aluminum has the best corrosion resistance, alloy 5××× series performs well, followed by alloy 3××× series and alloy 6××× series, while alloy 2××× series and alloy 7××× series are fairly poor. The type of corrosion resistance should also be determined according to the profile's application. All kinds of anti-corrosion composite materials should be used in conjunction with a high strength alloy used in a high corrosion environment.

Machining performance indicates how easily the profile can be machined by drilling, cutting etc. Because the formability of the extrusion is related to the temper, the strength range of various tempers should be taken into account after the aluminum alloy number is selected, and more often than not, an alloy with high strength is not so easily formed but rather easily machined. The opposite is true for alloys that are easily formed, they are generally not so easily machined. The formability of annealed material is generally the best, whereas that of the heat-treated material is the worst. On the contrary, the machinability of low-strength aluminum alloy is poor.

The ‘weldability’ of most aluminum alloys is generally not an issue, particularly the 5 series alloy, which is specially designed for welding. It is important to note that welding aluminum will generally compromise the strength and temper of the alloy and should only be done so by an experienced aluminum welder.

When industrial aluminum profiles are used in decorative instances, the surface is usually anodized, polished or powder coated. In order to obtain the appropriate color and surface texture, the decorative nature of the application should be considered. In general, good corrosion resistance alloys have good anodic treatment performance, surface treatment performance and coating performance.