Casting | Definition, Advantages, Limitations, Defects, Types

By | August 21, 2018

In this article we will learn following things about casting

  • What is casting
  • Advantages
  • Limitations
  • Types
  • Defects in casting

What is casting?

Casting

Attribution:┬áBy Ab5602 – File:Casting.jpg on en.wikipedia (Original: Own work), CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=579552

Casting is a manufacturing process in which molten metal is poured into a specially designed cavity. When metal cools down and becomes solid it takes the shape of cavity. This cooled solid metal is called casting. After this we take out that casting of desired shape and size from the cavity.

We can further do some work in this casting to make it fit for our use.

Advantages of casting process

  1. Any intricate shape may be internal or external can be made
  2. It is practically possible to cast any material
  3. Tools required for casting processes are generally inexpensive
  4. Cooling of casting is generally uniform from all directions hence it is generally does not have directional properties
  5. Many materials can only be processed by casting processes because of their metallurgical considerations
  6. It is practically possible to make casting of any size, even up to 200 tons

Limitations of casting process

  1. Generally Dimensional accuracy of casting products (in case of sand casting) are not so good and can not be used for final use. Hence, further processing of casting is required before final use
  2. Sand casting process is labor intensive
  3. With some materials it is not possible to overcome defects arising due to moisture present in sand.

Casting defects

1. Gas defects

  • Blowholes and open blows
  • Air inclusions
  • Pinhole porosity
  • Shrinkage cavities
  • Shrinkage cavities

2. Moulding material defects

  • Cuts and washes
  • Metal penetration
  • Fusion
  • Run out
  • Rat tails and buckles
  • Swell
  • Drop

3. Pouring metal defects

  • Misruns and cold shuts
  • Slag inclusions

4. Metallurgical defects

  • Hot tears
  • Hot spots

Special casting processes

1. Shell moulding

2. Precision investment casting

3. Permanent mould casting

4. Die casting

  • Hot chamber process
  • Cold chamber process

5. Vacuum die casting

6. Low pressure die casting

7. Centrifugal casting

  • True centrifugal casting
  • Semi centrifugal casting
  • Centrifuging

8. Continuous casting

9. Squeeze casting

10. Slush casting

11. Vacuum casting

2 thoughts on “Casting | Definition, Advantages, Limitations, Defects, Types

  1. Indra Kumar

    Amazing post dear..
    Love to know more about casting process as i’m a Mechanical Engineer!!
    Thanks!!

    Reply

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.