Alumínio fundido: Guia completo
Aluminum is an integral part of different industries as it offers excellent properties. Cast aluminum proves to be quite useful and is manufactured through an aluminum casting process.
If you want to learn about cast aluminum, its types, its process, etc., the guide below offers details. So let's read.
O que é o alumínio fundido?
Cast aluminum is a component that is manufactured using aluminum and other metals with the help of the casting process.
The process of aluminum casting is usually carried out by heating and melting the aluminum and other metals and combining them. Once the combined metals solidify, they take the shape of the mold they were poured into.
Cast aluminum has the properties of aluminum as well as other metals, and it has a coating of aluminum oxide over it. It is stronger and highly corrosion-resistant compared to basic aluminum metal.
The Casting Process of Aluminum
The process of casting aluminum involves various steps, but each step must be taken carefully to ensure all protective measures are followed. These steps are as follows:
Creating Mold Design
The first stage is creating the desired mold design. It features the final shape of cast aluminum. The mold is created using materials such as ceramics, steel, and even aluminum material.
It should be accurate in terms of size, shape, and acabamento de superfícies. The mold can be made using Maquinação CNC, and a coat of release agent must be applied on its surface.
Melting Aluminum
As soon as the mould is ready, the task of melting aluminum begins. It melts quickly as it has a low melting point and the process takes place in a furnace. Once it has melted, it is left aside to allow it to come at temperature ready to pour in mold.
Pouring Molten Aluminum
Molten aluminum and mold once ready, they will pour using a gate system which connects the mold and furnace. The molten aluminum is poured in the mold through a controlled manner and it prevents air pockets from forming.
Solidification of Aluminum
The mold is left for cooling; once cooled, it solidifies. The time for solidification would depend on the thickness of the product. The cooling rate also should be controlled so that an even solidification is attained.
De-molding Aluminum Cast
After solidification, you need to remove the aluminum cast from the mold. Once it is removed, the excessive material is trimmed, and the surface is finished as required.
Pros and Cons of Cast Aluminium
The pros and cons of cast aluminum are as follows:
Prós
- Cast aluminum is lighter than steel and cast iron. Applications that need a reduced weight can use it.
- It is corrosion-resistant and, hence, is suitable for most applications.
- Cast aluminum is suitable for heat-sensitive applications due to its thermal conductivity.
- It is easy to shape complex designs with the casting process.
- It takes less energy during the casting process.
- The process is highly affordable compared to other methods.
- It can be recycled to avoid environmental impact.
Cons
- Cast iron is not as durable as steel, especially when subjected to heavy impact.
- It can wear out over a period of time when subjected to abrasive applications.
- The issue of porosity is common in the casting process, which causes cracks and weak spots.
- Due to extreme cold in certain applications, cast aluminum may get brittle.
- The complex design ends up costing a lot.
Types of Aluminum Casting Processes
The aluminum casting processes of different types are discussed below:
Fundição injectada
Fundição injectada is the most common process of aluminum casting. It is divided into two processes: high-pressure and low-pressure die casting.
This process requires heating aluminum and injecting it into the die mold. Upon cooling, the cast aluminum is de-molded, and the cycle is repeated for more components.
The aluminum casting components manufactured using die-casting processes are known for excellent thermal and electrical conductivity. They are resistant to wear, corrosion and heat.
Sand Casting
Sand casting is a process which involves creating the mold for aluminum casting using sand.
Sand has the ability to withstand high temperatures and, therefore, is suitable for aluminum casting components. Molten aluminum is poured into the mold made of sand, and once cool, the component is removed.
Sand-casting aluminum doesn’t provide a smooth surface finish and even doesn't have high dimensional accuracy. Hence, it needs post-processing, like trimming.
Permanent Mold Casting
Permanent mold casting uses gravity to inject molten aluminum into the mold. Hence, the injection process has less turbulence. The aluminum casting components made using permanent mold casting have very high dimensional accuracy and excellent surface finish.
Cast Aluminum vs. Cast Iron
Cast iron and cast aluminum are the same in terms of appearance; however, their properties differ. Cast aluminum is lighter than cast iron and also maintains its durability. Also, the dimensional tolerance of cast aluminum is better than that of cast iron, and it is more machinable and precise.
Cast Aluminum vs. Wrought Aluminum
Cast aluminum has a high content of carbon compared to wrought aluminum. Hence, it is stronger. Wrought aluminum is either in the form of a plate or rod, whereas cast aluminum has a solid shape as the final component.
They both have alloying elements, but aluminum has a high silicon composition, making it more fluid in nature.
How to Choose the Right Aluminum Casting Process?
As you have read about the different types of aluminum casting processes, choosing the right one is very important. Some of the considerations are as follows:
Complexity of Design
The design complexity impacts the selection of the casting process. Aluminum casting components, which are large in size and have complicated designs, are usually manufactured through sand casting.
However, components that need dimensional accuracy are manufactured using a permanent mold casting process.
Production Speed
The speed at which you want the aluminum casting components manufactured is a consideration. For mass production, die casting is a suitable option as it uses a high pressure injection process. Sand casting is the second fastest process, whereas permanent casting is the slowest.
Quantity of Components
Die casting can make all types of aluminum cast parts. When you need high quantities, sand casting and permanent mold casting are suitable.
Surface Finishing and Durability
Permanent mold casting is a suitable choice if you need excellent surface and durability. However sand casting and die casting also ensure considerable strength, but surface finishing is better in die casting.
Optional Finishes for Casting Aluminum Parts
Cast aluminum components need further finishing for an enhanced surface; the different finishing options are as follows:
- Powder coating allows the dry powder to be applied to aluminum cast components, making them corrosion-resistant and durable.
- Cast aluminum components can be painted in multiple colors to add an aesthetic appearance.
- Electroplating is used to deposit a thin layer of material on the cast aluminum component, which adds a layer of protection to the component.
- Anodizing transforms the cast aluminum component into an anodic oxide finished surface. It makes the component highly resistant to corrosion and durable.
Common Applications of Casting Aluminum
The different cast aluminum types are used in multiple applications, and some of these industries where the components are used are as follows:
Indústria médica
Medical industry is highly dependent on cast aluminum parts due to their lightweight and strength. It is mostly used in manufacturing surgical trays and prosthetics. These components are corrosion-resistant and can work well when in contact with body fluids.
Indústria automóvel
Automobile industry uses aluminum casting components due to their lightweight and strength. These components enhance fuel efficiency. Also, the process can offer catering to complex components. Aluminum casting is used for vehicle components like steering wheels and brakes.
Indústria aeroespacial
Aluminum cast parts allow aircraft to make the most of their lightweight and strength. It helps the aircrafts consume less fuel and carry a high amount of weight conveniently.
Conclusão
Learning about cast aluminum, its manufacturing process, and its applications is very important before having the components manufactured. As you have read the guide, you have learned about the process.
If you need custom cast aluminum components manufactured for your applications, you can contact us at DEK.
