Forging Vs. Casting: Understanding the Difference

In this present day and time, with unsurmountable growth in technology, not so much has changed for ages in manufacturing processes. Casting and forging are still the most prevalent manufacturing processes. These metal fabrication methods have more or less stayed the same for hundreds of years. But then, what is the difference between forging and casting? What are their most common uses and applications?

What Is Casting?

Casting is the process of heating a metal material until molten. Then, the molten metal is poured into a mold and allowed to cool and harden, thereby taking the desired shape (the shape of the mold). The casting process is mainly applied in mass production of the same machine parts, reusing the same mold.

The casting process involves different methods, including sand casting, permanent mold cast, plaster casting, investment casting, and a lot more. Each casting method has its unique strengths and weaknesses.

What Is Forging?

Forging is the process of shaping metal through hammering, pressing or rolling. Forging is the use of force to direct the shape of a material in a solid state. While applying this force or energy will first deform the metal, subsequent application of this same pressure will give the material the desired shape.

What Is The Basic Difference Between Forging And Casting?

Unlike casting, which involves heating a metal to its melting point, then pouring the molten metal into a mold or vessel to create the desired size and shape, the forging process involves pressing and hammering the metal to the desired shape. While casting deals from liquid to solid state, forging is with a solid state.

During the forging process, the pressure applied to the material breaks down the naturally coarse grain structure of the metal. It replaces it with a more refined grain structure. The pounding action of forging improves the newly formed metal parts' structural integrity, making them more robust, durable, and reliable than cast metal.

On the downside, forging is faced with size and shape limitations. This metal fabrication process is more difficult, and working with a thicker metal will make the work more hectic.

On the other end, the casting process goes with a wide range of mechanical components. It covers diverse shapes and sizes that are too complicated, large, or unsuitable for the forging process. While you can use forging for reasonably significant machine parts, larger or more complex items are best left to the casting process.

Although casting is a more cost-effective fabrication process, metal parts produced through this fabrication process are more prone to defects (depending on the casting method used). These defects might be from uneven cooling, use of too much lubricant, low metal temperature, and so much more.

So, Which Is Better?

As with almost everything that has an alternative, one process is preferred over the other when it comes to certain projects. To help you pick the best process for you, here are the pros and cons of these processes.

Pros Of Casting

• More cost-effective

• Greater flexibility and versatility, as you can cast any material

• Permits both small scale and mass production

• Can cast complex parts

• Excellence design flexibility

Cons Of Casting

• Cast parts are more porous than forged parts

• Requires intense process control at all production stages

• Lesser tensile strength than forged parts

Pros Of Forging

• Superior mechanical properties

• Better ductility

• Reduces the chances of porosity, shrinkage, cavities, and other defects

• Greater wear resistance

• Potentially less expensive than casting through less labour and metal scraps

Cons Of Casting

• Requires long post-forging processes

• Limited in size and shape

• Products may not meet tolerance level

In large metal fabrication, there's no one size fits all approach. However, the bottom line remains that forging and casting are some of the earliest industrial processes. They are both used to manipulate the shape of metal. While forging will give you a more robust and more reliable part, there are certain situations in which casting will be the most viable alternative.

Whether you need forging or think that metal casting is best for your project, reach out to us at A&G Price.