Difference between Casting and Forging



Casting and forging are popularly used in various industries, although they are very different. They are usually used to create parts and components of industries.

What is Casting?

The casting process involves pouring molten metal into a hollow cavity mold and cooling it to form a solid part. Various types of casting are based on the casting process, Molding materials, and Filling pressures. And the main metal casting methods are Die casting, Sand casting, Investment casting, Permanent mold casting, Centrifugal casting, Shell molding, Lost foam casting, Plaster mold casting, Gray iron, Cast iron, Gravity casting, Plaster, and Lost wax casting.

  • Sand casting − Sand casting is a method in which the molding sand is used as a mold.

  • Die casting − Die casting is a process of molding materials under high pressure.

  • Investment casting − it usually makes patterns in fusible materials.

  • Centrifugal casting − Centrifugal method is where molten metal is poured into a rotating mold.

Casting tends to be lesser in cost and is not that expensive, and has more versatile options. However, forging comes with many advantages within itself and offers superior strength and resistance. What makes one better depends on itself and its advantages and disadvantages, and it depends on the top priorities for your project. For example, low-cost, exotic alloys and complex geometrics are the priority. If strength and structure are so concerned, forging is the best option compared to casting.

Benefits of Casting

  • Any shape, no matter external or internal, can be made.

  • In casting, it is practically possible to cast any material.

  • The casting tools are generally not that expensive compared to other manufacturing processes.

  • Because of the metallurgical considerations, many materials can only be processed by the casting process.

  • It is possible to make a casting of any size, even up to 200 tons.

  • It is cheaper compared to other manufacturing processes.

Drawbacks of Casting

  • Low strength occurred due to high porosity compared to a machined part.

  • The melting point is very low in casting.

  • Casting is not suitable for low-volume production.

  • It requires additional [secondary] machining operation to improve the surface finish.

Importance of Casting Process

  • The casting process is widely used in manufacturing complex parts.

  • The casting produces the best quality sand casting products at a very reasonable price compared to the machining process.

  • They have a very high production rate.

What is Forging?

In this process, forging uses dies, pressure, and temperature to shape a piece of the round metal bar into a shape. Usually, there are three ways to classify forging; the first one is by temperature [cold forging, warm, or hot forging], then comes types of the process [open or closed die forging] or material used [steel forging, aluminum forging, brass forging, or bronze forging].

Benefits of Forging

  • The parts manufactured by forging are very strong.

  • It gives a guarantee of high ductility, and it is more reliable and less costly.

  • It offers more consistency, and the metal is refined.

  • It gives a better response to heat treatment and more flexibility and has excellent design flexibility.

  • It guarantees an excellent offer of the size range of products.

Drawbacks of Forging

  • One must be highly safe while doing it because it can be harmful, and materials safety procedures must be followed.

  • The capital cost is very high.

  • It is tough to maintain close tolerances

  • The biggest drawback is that it is tough for the forged metal surface to be prone to rapid oxidation due to very high temperatures.

Importance of Forging

  • The main point to remember here is that forged products are used in every mechanical industry.

  • Forged is primarily used in hand tools and hardware manufacturing.

  • It is mainly used in shipbuilding in various structure work.

Difference between Casting and Forging

The following table highlights the major differences between Casting and Forging −

Factors
Forging
Casting
Structural level
It has superior strength compared to casting. It has a high level of material predictability.
The casting products tend to be more permeable and are an easy target to breakage compared to forgings.
Tolerance
Tolerance is not that well suited to highly complex geometrics.
Casting allows for high-level detail and is capable of adhering to tight tolerances.
Product size
They are constrained in terms of the thickness and size of the metal.
Here they are a compatible wide range of size and thickness.
Material selection
The selection of the alloys is minimal.
And here, they are compatible with all types of metal and show no slight problem with the adjustable.
Cost
They are very costly in terms of cost-effectiveness for medium to large production runs.
They are generally less expensive than the forging, but sometimes it all depends on the casting method.
Secondary operation
Here they usually require secondary operations to purify and finish products to exact specifications.
Casting provides a primary level of products that will be required in very few secondary operations.

Conclusion

Castings are melted, poured, and made into solid form, while forging is physically forced into a shape while remaining in a solid-state. As a result, these are the two processes from end-products with very different characteristics from each other.


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