Forged vs. Cast – What’s the Difference?

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Differences Between Forging and Casting Metal

Forging and casting are two very different manufacturing processes used to manipulate the shape of metal. In the casting process, metal is heated until molten. Then it is poured into a mold or vessel to create a desired shape. In the forging process, material is pressed or hammered into a certain shape while still maintaining a solid state. So why do we choose to forge?

Forging is stronger than casting.

One of the main reason we choose to provide forging services is that it provides a stronger end product for our partners. According to a study performed by the Industrial & Manufacturing Engineering Department at the University of Toledo:

  • Forged parts had a 26% higher tensile strength than the same cast parts.
  • Forged parts had a 37% higher fatigue strength resulting in a much longer lifespan than cast parts.
  • Cast iron only had 66% of the yield strength of forged steel, a measurement that indicates the load amount metal can hold before deforming.
  • The forged parts had a 58% reduction in area when pulled to failure, compared to 6% reduction for cast parts. That means forge parts allow for much greater deformation before failure than cast parts.

Why is this?

When you melt metal, the grain size is free to expand. This creates a final product with a more random grain structure. A more random grain structure leads to deceased strength. The forging process keeps the grain structure tight and the product mechanically strong. There is also less need for expensive alloys to retain high strength.

Why use castings?

The main benefit of casting is to create components that are too large, complex, or otherwise unsuitable for the forging. We can forge part sizes up to 18” in length and weights up to 100 pounds. But if you are in need of an end product weighing 5000 pounds, casting would be a more suitable option. So use casting when:

  • Your part is too large to forge.
  • The part is complicated (contact us for advice on this)
  • Part requires custom alloys added

Why use forging?

If your end piece is able to be forged, it should be forged. This will give your part better strength, more consistency, a tighter grain structure, and longer lifetime. Reach out to our engineers to see if forging is right for your project.