Aluminum vs Cast Aluminum: What’s the Better Option? 

The debate about the more general form of aluminum (wrought aluminum) against cast aluminum has been storming for many years. Users regard aluminum for its higher strength, durability, and minimal porosity. Despite its porosity and strength challenges, cast aluminum is renowned for design flexibility, lower cost, and suitability for high production volumes. 

It is therefore understandable if it is confusing which other two aluminum varieties to pick for a project. But how exactly do these two materials compare? The only way to answer this question is to closely check the manufacturing processes, properties, applications, and advantages/disadvantages of each of these options.  

This article seeks to address any confusion about aluminum vs cast aluminum so users no longer have to ponder over the matter before using any of the materials.  

Read More: Die Casting Parts: A Guide to Manufacturing, Uses & Cost

Aluminum Basics and Suitability for Projects

Aluminum is a lightweight material popular in different industries for its durability, recyclability, and strength-to-weight ratio. It is a highly abundant material on the earth’s crust. The metal is non-ferrous, and very pliable in its original form. 

To make aluminum more usable, engineering firms add elements to form alloys. Depending on the alloying elements or materials, aluminum forms alloy series such as 2000, 4000, and 7000. 

Wrought aluminum (aluminum) comes from smelted aluminum ingots treated with the right alloys. The smelted product is then mechanically worked using methods such as forging, extruding, and rolling to attain the desired shapes. 

Aluminum ingots ready for further processing 

Alt text: Round profiled aluminum rods of equal diameter viewed in closeup

Whatever your intended project is, aluminum is extremely versatile, especially with all the alloys available. There are many aluminum alloys, each with unique properties and suitability. This brings another confusion, which will be addressed in another post, about choosing the exact aluminum alloy for the job. 

What are the aluminum grades to consider? 

Below is a table showing the different aluminum grades and their main properties. 

What is cast aluminum?

Casting for Aluminum

Alt Text: A Crucible pouring orange hot molten metal on a surface 

Cast aluminum is a metal variety that emanates from raw aluminum being heated to a molten state and then poured into a mold. After solidifying, the material is removed from the mold as a final product of metal-casting aluminum. This process differs from aluminum manufacturing because there is no further mechanical work.  

The “casting” process results in a more affordable type of metal. It allows for the manufacturing of complex shapes of metal casting aluminum, thus its popularity in industries such as cookware, automotive, and furniture. It is the material of choice for gearbox and engine block manufacturing. The ease of use makes it ideal for some components in the automotive and aerospace industries. 

On the flip side, cast aluminum is relatively weak and difficult to machine. This is due to the likelihood of porosity or air pockets forming during the casting process.

What are cast aluminum alloys? 

The various examples of cast aluminum alloys are highlighted in the table below.

Consider the following points for aluminum vs cast aluminum.

In comparing and contrasting aluminum vs cast aluminum, what matters is identification of the different properties of the materials and how they affect applications. 

The following table provides a summarised look at the properties. 

Cost: 

The manufacturing process can have a huge effect on the cost of a product, a reason why wrought aluminium tends to be more expensive than cast aluminum. Forging, extrusion, and all the other mechanical processes for wrought aluminum are much more resource-consuming than what it takes to manufacture cast aluminum. 

When it comes to high-volume production of complex items, cast aluminum grades become even more cost-effective. Some industries overlook cast aluminum’s drawbacks in mechanical properties simply because they can use the metal to manufacture complex designs at an affordable rate. 

Applications:

Wrought aluminum is renowned for its high strength, thus it is suitable for uses where strength is a primary concern. The higher strength emanates from the more uniform grain structure that forms during the manufacturing process. You will find wrought aluminum in aerospace and other high-stress areas. 

As for cast aluminum grades, durability is evident, although the alloys under this category have lower density due to micropores. How strong is cast aluminum? It is not as strong as wrought aluminum. As long as the strength requirements of an application are not that high, cast aluminum is a suitable material. An ideal application for cast aluminum is a car’s gearbox.  

Machinability:

Wrought aluminum’s grain structure is more uniform, so this material is easier to machine. With a reputable company in aluminium die-casting services in China, you can achieve smoother surface finishes and tighter tolerances with the material. Prolean Tech uses advanced machining processes that are flawless on wrought aluminum and other materials.

CNC Turning

Alt text: A close-up image of a state-of-the-art CNC machine turning a metal component 

It is more difficult to perform machining operations for cast aluminum. The grain structure is already distorted so the material exhibits uneven strength and hardness. Such unevenness can be problematic to the cutting tool and affect the surface finish of the aluminium casting products. 

Complexity of products: 

Cast aluminum allows for the production of complex shapes. The same complexity level may be unachievable with aluminum. The ease of creating shapes is the same reason the less experienced machinists find it easier to work with cast aluminum than with wrought aluminum. 

Production process: 

Wrought aluminum is manufactured by mechanical working processes such as forging and extrusion. These methods subject the material to mechanical deformation and results in uniform microstructure and better mechanical properties. During this process, the machinist has significant control over material thickness, shape, and other parameters. The resulting aluminum version is relatively strong and ductile. 

This is different from the cast aluminum production process, whereby the tolerances are not that tight. Further processing may be required to achieve the desired parameters of the product. 

Final Verdict: Align properties to specific needs of the industry

This article has provided an overview of the properties, applications, pros, and cons of aluminum vs cast aluminum. One thing that comes out is that each of the featured categories of aluminum is advantageous in many aspects and has widespread applications in different industries. 

Ultimately, it is all about understanding what a material offers in corrosion resistance, impact resistance, tensile strength, and all the other crucial factors. 

The insights offered can be helpful whether you are looking to introduce a new product into the market or enhance the production of an existing product. If any point on aluminum and cast aluminum grades is unclear, consulting a professional can help.  

Prolean Tech is a go-to provider of popular and relevant services, including rapid prototyping and CNC machining.