There are multiple mechanisms utilized for the manufacturing or fabrication of metals and components of metals. Two common methods include Casting and Forging which are in practice for many centuries.
There is a possibility that these two methods may be considered synonymous as they can at times be used as an alternative for the other, however, there exist spring differences between these two.
Casting vs Forging
The main difference between Casting and Forging is that Casting is the process where metal is heated until it is molten (i.e. melts) and then later put in a vessel to provide the needed shape, while in Forging metal is heated by using thermal or mechanical energy and later hammered to give the desired shape.
However, the above is not the only difference. A comparison between both the terms on certain parameters can shed light on subtle aspects:
Comparison Table Between Casting and Forging (in Tabular Form)
| Parameter of Comparison | Casting | Forging |
|---|---|---|
| Meaning | Metal is heated till it melts and afterward, it is poured into a die to provide a certain shape | Metal is subject to heating and afterward, it is hammered to provide a specific shape |
| From expenses/cost perspective | Casting is less expensive but depends on the methods employed | More expensive than Casting |
| Which is the old method? | Casting is a very old process that maybe dating back to thousands of years. | Relatively new compared to Casting and is a method used since the 12th century |
| Under which method the metals become strong? | Metals are not so strong as compared to Forging | Metals become stronger |
| Suitability for complex metals | Yes | No |
| Suitability for Large size materials | Yes | No |
| Could there be a requirement for the materials to be further processed by a machine? | No | Yes, this can happen in case of complex materials which may not come in the desired shape and hence further processing by machine needed |
| Which materials ideally suited for Casting? | Steel, brass, iron, aluminum, and tin | Alloy steel, carbon steel, titanium, copper |
What is Casting?
Casting is the process where metal is heated until molten. While in the molten or liquid state it is poured into a mold or vessel to create the desired shape. Casting in simple terms means something cast in a mold. In Casting, the liquid form of metal is poured (gushed) into a mold (which can be either open or closed) and later allowed to cool to a solid-state. This process enables the materials to gets into shape during the cooling stage.
Casting can be of multiple types such as die-Casting (liquid metal is put into a die i.e. a special shape metal instead of a mold), permanent Casting (putting the molten metal in a metal mold), sand Casting (a slow process in which Castings are made by pushing a specific design into a sand mixture).
Also, there could be other methods such as vacuum process molding, investment Casting, plaster Casting, etc. All the said methods come with certain pros and cons.Casting can be used for components or applications that are larger or in other words where there is no higher size limit.
Casting is a preferred method in such scenarios. Casting will also be used for parts that are considered unsuitable for Forging.
What is Forging?
Forging in simple words means to form something by heating and later hammering or beating to provide the required shape. Under Forging, a high amount of compressed force is applied to strike the material into shape.
Again, once Forging is performed, a certain degree of machining may be mandated to put the material into the desired shape especially in case of complex materials. Forging involves the use of automatic or electrical energy to provide the needed shape to the material.
Forging can be done in various methods such as cold forging (forging performed at room temperature), warm forging (performed at above room temperature), hot forging (performed at recrystallization temperature). Other methods also include open die forging, closed die forging, press forging, roll forging.
Forging offers multiple advantages such as consistency in the metal structure and uniformity of configuration. The steel produced under the Forging process is considered stronger from an impact standpoint.
Forging is ideally suited to smaller size material as a lot of force needs to be exerted to put the material into a shape that may not be possible or very difficult in case of larger size materials. Forging may be suitable in cases where the design of the product is an important aspect.
Main Differences Between Casting and Forging
- Casting involves heating the material until it melts and later pouring into a vessel for providing certain shapes. Forging involves the use of mechanical and thermal energy to heat and hammer the metal to provide the desired shape.
- Casting may not create metals which are tough and able to withstand significant pressure. Forging can create metals that are tougher and stronger as the process itself involves pressing or hammering which provides the ability to the metal to withstand pressure from the initial start.
- Casting enables the alteration of the shape of metal easily. Under Forging, shaping a metal may be difficult as the metal is in solid-state.
- Casting can be performed for large material. Forging may not be an apt choice for larger size materials as it will become difficult or apply force to such huge sized materials.
- Casting is less expensive than Forging.
- Casting may enable the production of materials that are complex or thick. In Forging, it is difficult to manufacture materials having a complex structure.
Conclusion
Casting and Forging enable the creation of high quality and technically advanced metal products. However, there will also be a lurking question as to which method should be the preferred one for deployment in the manufacturing process. The choice-making may become difficult as each method offers multiple but distinct sets of benefits and comes with certain cons.
The selection of either Casting or Forging will depend on the assessment of multiple factors such as the cost, the type of components, the size and complexity of components, the end product envisaged, the time factor, etc.
Therefore, it is important to assess these aspects and also the individual needs before deciding to adopt either the Casting or Forging process. It would be a prudent idea if the assessment of their subtle differences is undertaken before deciding on their use as both methods differ from each other from a practical standpoint.
Expert advice, especially from experienced metal/materials manufacturing agents, is suggested to reap the full benefits of either the Casting or Forging deployment in actual practice to have superior quality finished products.
References
- https://www.scientific.net/SSP.116-117.34
- https://journals.co.za/content/ergosa/22/1/EJC33288
- https://www.sciencedirect.com/science/article/pii/S0921509397008101