Aluminum cast refers to a specific component that is created from aluminum or any other materials using the aluminum casting technique. It is an essential part of industries that require the strength, durability, and lightweight of aluminum as well as compatibility with complicated product design.
There are a lot of aluminum casting processes that are being used right now and each of them has specific requirements and setup.
That is why casting aluminum parts with various properties can be made possible. Here, we are going to learn more about aluminum casting and determine which of these are the appropriate ones for your project.
What Is Aluminum Cast?
The aluminum cast is a term used to describe a specific part created from aluminum or any other metals using one of the different aluminum casting processes.
Typically, these aluminum casting processes are done by heating the aluminum or any other metal being used, then pouring this molten metal into the mold, which is created based on the product design. Once the molten aluminum has cooled down and hardened, it will take the form of a cavity.
The properties of aluminum and any other metals are then embedded into the aluminum cast. Additionally, an exterior coating of aluminum oxide will be developed, making it stronger compared to any other conventional aluminum material. At the same time, it can also help in preventing corrosion.
What is the Difference Between Cast Iron and Cast Aluminum?
When it comes to appearance, cast iron and cast aluminum have some similarities. However, they differ in inherent properties and base material. Let’s try to compare both materials.
Cast aluminum is lighter compared to cast iron, without affecting its durability and strength. When it comes to dimensional tolerance, the aluminum cast offers more than cast iron.
This is because of the softness that aluminum brings compared to iron. Furthermore, since aluminum offers more softness than iron, then it can provide more accuracy, precision, and machineability. Compared to cast iron, cast aluminum has an improved heat capacity. Moreover, once it is heated, its heat will lose faster compared to cast iron.
What is the Difference Between Wrought Aluminum and Cast Aluminum?
The carbon content of cast aluminum is much higher compared to wrought aluminum. Furthermore, it has stronger mechanical properties and is more durable. Let’s look at the three relevant differences between these materials.
- Product forms vary – Wrought aluminum comes in a rod or plate form since it is mostly applied in aluminum extrusion or CNC aluminum machining. While cast aluminum typically has a solid shape depending on the final product or on the billet form.
- Alloying elements differ – Although the alloying elements in both materials are the same, nevertheless their quantities and composition differ. For instance, there is a higher percentage of silicon in cast aluminum. Additionally, they have improved fluidity.
- Product properties are unique – Between these two components, cast iron aluminum is much stronger. On the contrary, wrought aluminum has excellent dimensional accuracy, improved machinability, and higher tensile strength.
What are the Different Types of Aluminum Casting Processes?
Basically, there are three major types of metal casting processes that are appropriate for aluminum. Let’s find out what are these processes as well as their characteristics.
One of the most common types of casting process used in manufacturing is sand casting. It is more appropriate in this industry since sand has the capability to withstand elevated temperatures.
This process is done by creating mold using sand. Then, the next thing to do is to heat up the aluminum material. When done, it will be placed into the sand mold. Once it has cooled down and solidified the cast aluminum part will be removed from the mold.
Unfortunately, aluminum sand casting has a rough surface and low dimensional accuracy. That is why, most of the time, post-processing procedures will be required such as trimming. This aluminum casting process is usually applicable to making gas and oil tanks, fittings, aluminum gears, and many more.
When it comes to casting aluminum components, die casting is the most well-known aluminum casting process. Die casting has two processes – high-pressure die casting and low-pressure die casting.
Among these two, high-pressure die casting is the most appropriate for the material. Die casting is done by preheating the aluminum first, then inserting it into the die mold under high pressure.
The design of the die mold will greatly depend on the intended output. After it cools down, the cast aluminum part will be removed from the die mold. And the same process will be done once the die mold has cooled down.
One of the greatest advantages of the die-casting process is that the generated die-cast aluminum has effective thermal and electrical conductivity. Moreover, they can resist wear, corrosion, and heat, in addition to being stronger. Die-cast aluminum parts are usually used for the mass production of components in the aerospace, culinary, and medical industries.
Permanent Mold Casting
Die casting and permanent mold casting are the same. However, these processes differ in the method of inserting the aluminum into the mold. Contrary to die casting, rather than using low or high pressure in filling the mold, gravity is used for permanent mold casting. This can help in minimizing turbulence while the injection process is going on.
The aluminum casts produced using this process are much stronger with close dimensional accuracy and excellent surface finish. The permanent mold casting process is more applicable to creating aluminum components in the aircraft and automotive industries.
How to Select the Appropriate Aluminum Casting Process
Each of these casting processes has its own advantages and disadvantages. The following factors can help you in choosing the appropriate procedure for your project.
Speed of Production
A pressurized injection process is being used in die casting. Hence, it is ideal for the mass production of specific aluminum components. When it comes to speed, sand casting is the second best, while permanent mold casting comes last.
The intricacy of the design of the component also plays an important role, when it comes to choosing the casting process.
Most complicated and large aluminum casting components are usually produced using sand casting, which is recommended for products that have complex designs. For cast aluminum components that need to be dimensionally precise, a better option would be permanent mold castings.
The best process for prototyping is sand casting since it only requires a low investment. Unfortunately, the other processes require a higher investment, which is not practical since there are only a few pieces required in prototyping.
When making several aluminum cast components, the most appropriate process is die casting. Nevertheless, if you want to achieve a balance between tooling and high quantity, then the best options are permanent mold casting and sand casting.
Surface Finishing and Strength
An excellent balance of good surface finishing and strength can be acquired with permanent mold casting. However, die casting and sand casting have good strength as well. Additionally, die casting has a good surface finish as well.
What are the Different Finishes Used for Casting Aluminum Components?
Optional finishing processes can either be for functional or aesthetic purposes. Some examples of finishing processes are painting, powder coating, anodizing, and electroplating.
SEI Castings manufactures high-quality accurate aluminum die-cast products. For more details about our products, just call us at (408) 374-1031.