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4 common types of metal casting processes

There are different types of metal casting out there. They are specifically suitable for specific applications. The metal casting process is a manufacturing process in which metal is melted to be poured into a cavity. Casting has been done for ages, ever since the production of parts came into existence.

Metal casting can be typically used to produce a large variety of parts that are used in different industries. Different types of metal casting lead to the production of certain casting quality, complexity, properties, manufacturing cost, surface finish, dimensional accuracy, etc. All these properties are considered when selecting a suitable type of casting process for an item.

Read more: Everything you need to know about foundry processes

Today you’ll get to know the 4 common types of metal casting. Some of these casting processes are used for producing a certain type of item while, some are used to produce complex parts.

Types of metal casting

The common types of metal casting include sand casting, investment casting, die casting, and evaporative casting.

Sand casting

Sand casting processes are manufacturing process that uses sand to create a mold cavity. The sand serves as refractory material that can resist a molten metal. Greensand is usually implied because it has good binding properties, such as sand, clay, silica, and little amount of water. Pattern made of either wood or metal is used to create a good replica or model of the item to be produced, leaving the same shape in the mold cavity. Patterns are created to be slightly larger than the original item, to contract the molten metal during cooling.

Read more: Difference between Forging and Casting

Sand casting is normally used when the larger part is needed to produce, its production is relatively inexpensive, especially when producing low-volume. The sand casting process offers a low cost for post-casting tooling, and ferrous and nonferrous metals can be used for casting. However, sand casting produces a comparative rough surface, making it require finishing work. It also yields a lower degree of accuracy. Sand casting processes are slow, as the mold must be break when bringing out the casting.

Read more: Understanding sand casting process

Type of metal casting process

Die casting

Die metal casting usually involves nonferrous metals and alloys, such as tin, zinc, aluminum, and copper. Its end product offers a better surface finish and good dimensional accuracy. This metal casting process is carried out by forcing molten metal into a mold at high pressure. The mold is coated with a lubricant, for easy injection of the molten metal. And to regulate the die’s temperature.

Read more: Different Types of Nonferrous Metals and their Uses

Molten metal is rapidly injected into the die under high pressure. Rapid insertion helps to prevent a segment of the casting from hardening before its remaining part. After the molten metal solidifies, the casting is taking out of the die, then the craps materials will be cut off.

Die casting has relatively high tooling costs, making it more cost-efficient when producing high-volume. Porosity defects are common in die casting when producing large items. This is because air is entrapped, and due to the solidification of the molten metal before it reaches the die cavity.

Read more: Understanding die casting processes 

Types of metal casting process

Investment casting

Investment casting is another type of metal casting process, that offers a high degree of accuracy, and dimensional results, a relatively high-quality surface finish. It is capable of creating thin-walled parts with complex geometries. Just as sand casting, investment casting also has the capacity of casting both ferrous and nonferrous metals.

Read more: Different types of Casting tools and equipment

The metal casting process uses disposable wax, usually beeswax to create a pattern or model of the casting. The pattern (wax) is placed into the mold. This wax is pre-coated with a liquid refractory material, dried in sun, or heated before placing into the mold, helping the pattern to be able to resist the molten metal for a little amount of time.

After the injection of the coated wax into the mold, molten metal is poured and it takes a position of the pattern. The pattern melts out and the metal solidifies taking the shape of the melt-out wax. Investment casting is widely used in the manufacturing of aerospace, automotive, and military parts.

Read more: Understanding investment casting processes

Process of investment casting

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Centrifugal casting

Centrifugal casting is a special type of metal casting that is implied when the durability of a product is important, the internal diameter of casting to have fine grains, and generally, where hollow parts are needed. Centrifugal casting is carried out in a permanent mold, that allows molten metal to be poured into it.

The mold spins at high speed around its axes. Due to the centrifugal force, molten metal is thrown towards the mold walls. It solidifies and the casting is taken out of the mold. The centrifugal casting process is performed when a part such as spherical glass objects, pipes, flywheels, boilers, television picture tubes are needed.

Read more: Understanding centrifugal casting processes

Working principle of centrifugal casting

That is it for this article, where the four common types of metal casting are discussed. I hope you got a lot from the reading, if so, kindly share with other students. Thanks for reading, see you next time!

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