Cast Aluminum vs Extruded Aluminum – Difference Between Aluminum Extrusion and Casting


Aluminum is a great candidate when looking for the best material for specific applications and is easy to work with through different production techniques. Among various aluminum fabrication process, today we’ll compare aluminum extrusion and aluminum casting, how do these two processes work and what’s the difference between cast aluminum and extruded aluminum?

What is Aluminum Extrusion?

Aluminum extrusion is the process of using high pressure to force aluminum material through the metal die to create an extruded aluminum profile or shape. The heated aluminum billet is put into the cylinder or container, and then forced through the container through the ram under the pressure of up to 100000 psi. The die stack at the far end of the container maintains the opening of the die. Once the material is extruded, it will be cooled by quenching, stretched to specific straightness, and then checked. Finally, the extrusion is aged to the required tempering state, the physical and chemical properties are tested, and further manufactured and packaged for shipment as required. Aluminum extrusion is an economical production method especially when complex cross-sections are needed. Typical shapes and features can be made by extrusion process including hinges, flanges, press and snap, tongue and groove, sliding fits, etc. And extruded products include door frames, window frames, heat sinks, manifolds, etc. 

Advantages of aluminum extrusion

– Lightweight and high strength-to-weight ratio

– Affordable and cost-effective

– Can conform to tight tolerances

– Attractive surface finish

– Flexibility of operation

– Wide range of products

– Simple process and low equipment investment

– Improved structure and mechanical properties

What is Aluminum Casting?

Aluminum casting is a process in which the heated liquid aluminum or aluminum alloy is poured into a mold, to produce aluminum casting parts or aluminum castings with limited shape and size. Aluminum casting can produce metal parts with high tolerance, high quality, and complex shape. Common aluminum casting methods including permanent mold casting, sand casting, investment casting and die casting. The type of mold makes one casting process differ from another, casting mold can be permanently made of steel or temporarily made of a non-metallic material. Every kind of aluminum casting has its advantages and disadvantages.

Advantages of aluminum casting

– Excellent dimensional accuracy 

– Close tolerance is consistently held

– Complex and intricate shapes

– Complex shapes with thin walls can be cast

– Can produce near-net-shape parts 

– Can withstand the highest operating temperatures

Cast Aluminum vs Extruded Aluminum - Difference Between Aluminum Extrusion and Casting

Cast aluminum is generally made with a lot of pot metal which would be a mixture of different grades of aluminum that are not going to be properly sorted or separated, the cast aluminum is generally used in lower grade applications. Extruded aluminum is very strong and can be used for handling high-load applications. Extruded aluminum is popular in electronics, telecommunications, automotive, solar energy, and more industries. Then what’s the difference between cast aluminum and extruded aluminum?

1. Aluminum extrusion can only create shapes with a consistent cross-section, while aluminum casting can produce a variety of complex and intricate parts, it is commonly used to manufacture large products. 

2. Extruded aluminum usually has a very smooth surface finish, while cast aluminum often gets a rough surface and requires secondary machining or processing.  

3. The size of aluminum extrusions is limited by the size of the aluminum billet, aluminum castings are available in a wider range of dimensions. 

4. Extruded aluminum products are generally stronger than cast parts. A casting may contain some porosity or other defects. 

5. Aluminum casting is a more pricey fabrication process than extrusion due to the high initial costs. Additionally, the mods used in aluminum casting is more time-consuming and expensive than extrusion dies. 

6. Aluminum casting is more suitable for a long production run and aluminum extrusion is more ideal for a short production run.