Die castings are usually produced using non-ferrous metals such as zinc, copper, aluminum, lead, magnesium, and pewter. The type of metal used determines whether a cold or hot chamber machine is used. Ferrous metals can also be used, but it is not common.
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Main die casting alloys and their advantages
Several factors will determine the type of metal or metal alloy used for the casting. This includes the product and its function, cost as well as the metal properties. Each type of metal has its own advantages, for example:
- Aluminum: Lightweight, corrosion-resistant, high thermal and electrical conductivity, ability to withstand high temperatures, and high dimensional stability.
- Zinc: Easy to cast, easy to plate, high ductility, high impact strength, cost effective and promotes long life for the dies that are being used.
- Magnesium: Easy to machine, one of the lightest alloy that is usually die cast, good strength to weight ratio.
- Lead / tin: Close dimensional accuracy, high density, corrosion resistant.
- Copper: High corrosion resistance, high mechanical properties, high wear resistance, good dimensional stability, excellent strength and hardness.
- Silicon tombac : This alloy is a combination of copper, zinc and silicon. It is high in strength.
Die casting applications based on the metal used
Aluminum die casting applications
Aluminum is widely used for die casting and its application is found in a vast number of industries.
In the automotive industry, aluminum die cast automotive parts have been used as a replacement for iron and steel parts. Because it is lighter, it helps to decrease fuel consumption. It is also applicable in the aerospace industry, where there is an increasing demand for lightweight components.
Aluminum die cast products can also be found in electronic connectors and housings. Its excellent electrical performance as well as shielding properties make it suitable for products that are used in this sector.
Additionally, the shielding properties also mean that it is a good choice of material for handheld devices that need to be durable as well as have EMI/RFI shielding.
You will also find aluminum die cast products widely used in the building and construction industry. Window frames, curtain railings, partitions, fittings and cladding are some aluminum die casting that you will commonly see in this sector.
Zinc die casting applications
Zinc die casting is very important in the automotive industries because of its strength and hardness. You will find zinc die castings used in the fuel systems, brake systems as well as air conditioning systems of vehicles. Besides this, it is also used to produce engine components as well as power steering components.
It is also used in the electrical and electronics sector as it has excellent electrical performance and shielding properties because of its superior thin wall capabilities.
Besides this, the easy castability of zinc makes it suitable for multi-faceted, complex shaped products.
Magnesium die casting applications
As the eight most common element on earth, the cost of magnesium is quite low when compared with other metals. It shares many of the same qualities as lightweight metals and is often a choice when it comes to combined die casting.
Magnesium die castings are commonly found in the following industries:
- Electronic Casing and Housings – While magnesium die cast alloys have great conductive abilities, they are great for shielding against electromagnetic and radio interference. You will find magnesium alloy castings being used to make protective casings for smartphones, tablets, laptops as well as televisions.
- Automotive Industry – Magnesium die cast alloy components are used in high performance vehicles such as sports cars. Light shell castings are used to reduce vehicle weight and thereby increase vehicle speed and fuel efficiency.
- Aerospace Industry – Because magnesium die cast alloys are lightweight, durable, and have high insulation properties, they are also a choice option for aircraft, and spacecraft.
Tin die casting applications
The properties of tin include a low melting point, good molten fluidity, as well as a readiness to form alloys when combined with other metals. Tin is non toxic and also solderable.
Tin is commonly used as a constituent of soldering and coating for steel. It is a choice metal used in bronze, pewter and bearing alloys. It is a metal that is usually alloyed with copper, lead, zinc and bismuth.
Tin and its alloys are easy to cast and extruded. Because little shrinkage happens during solidification, tin alloy castings have high dimensional accuracy.
Tin is often used for non critical parts. Many decorative items and costume jewelry are manufactured using tin based alloys.
Tin alloy castings are also used for precision parts and bearing for household appliances, motors and generators, engines as well as gas turbines. As it is a non toxic metal, numerous food handling equipment are made from tin castings.
Die casting applications based on process
Hot chamber die casting applications
Hot chamber die casting refers to die casting machines that have a casting chamber in which the molten metal or molten metal alloy is pressed.
The molten metal passes through a valve to the casting chamber.
It is then pressed at high speed into the die casting mold by a piston. Once it cools, the casting is ejected. The cycle is repeated to create the next casting.
Hot chamber die casting is used for alloys with a low melting point, such as zinc, lead and tin. As such, the applications of this process are numerous, including all zinc, magnesium and tin die castings as mentioned in the sections above.
Applications of hot chamber die casting can be found in the automotive and aerospace industries, food production industry, building and construction industries, electrical sector and many others.
Cold chamber die casting applications
Cold chamber die casting machines have the casting set located away from the melt. To make a casting, the casting chamber is filled with the alloy and pressed into the die cast mold. The casting is solidified under strong pressure and the dies are opened.
It is a process that is suitable for metals that have a higher melting point, such as aluminum and copper. Cold chamber die casts can be seen in handheld devices, electronic components, and electric housings.
Conclusion
Precision die casting is an important process that manufactures parts and components for a vast number of industries. The type of metal, as well as process depends on the function, shape as well as cost of the end product.
If you are looking to die cast a product, look for trusted die casting manufacturers that are able to give you advice on which type of metal to use based on your application. Eko Industries, a Malaysian based company specializing in die casting helps to optimize the whole production process from design to the end product.
The article is a part of our comprehensive guide on “Die casting: Process, Equipment, Uses, and More”
