The Difference Between Casting & Forging

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 a desired shape.

Forging is the application of thermal and mechanical energy to steel billets or ingots to cause the material to change shape while in a solid state.

Why use castings?

We use castings for a wide range of wearparts and components that are too large, complicated, intricate or otherwise unsuitable for the forging process. We can forge parts up to 50kgs but the sheer energy required to forge larger items make casting a much more viable alternative.

The advantages of casting include:

No real upper size limit in casting weight

Large range of alloy choices

As forgings remain solid, custom alloys are far more difficult to get into production whereas with casting, alloys including Chrome, Nickel and Moly can be added at the molten stage.

Tooling is often less expensive than forge dies

Smaller production “runs” required

Complicated/complex parts are no problem

For general GET as well as large and complex components - casting is a fantastic method of manufacture.

Investment Castings -- Precision Parts

JSD Metal has more than 15 years’ experience in precision Investment casting. Investment casting, also known as Lost wax casting, can be used to produce a wide variety of precision parts from many alloys and metals, including aluminum, stainless steel, carbon steel, brass and bronze. The investment casting process offers numerous advantages over other casting, machining and manufacturing methods.

Investment Casting vs. Sand casting:

Compared to sand casting, lost wax casting offers tighter dimensional tolerances, better surface finishes, produces near-net shape parts which therefore require less machining and other processing, and allows for the casting of complex-geometry parts and intricate details such as lettering and logos.

Investment Casting vs. Machining:

Precision investment casting offers lower per piece costs over long production runs, significantly less material waste thereby reducing material costs, and the ability to work with a larger selection of alloys. Additionally, machining offers no economy of scale with volume (ten thousand parts cost as much per piece as ten parts).

Investment Casting vs. Metal Fabrication:

Investment casting can be far more accurate and precise than metal fabrication, is less labor intensive, often offers substantial weight savings, costs less, provides more material choices, greater design flexibility, shorter lead times, and quicker prototyping. Additionally, while using metal fabrication may require parts to be constructed from multiple individual pieces, precision investment casting allows for the same part to be made in one continuous piece.

Investment Casting vs. Die casting:

Lost wax casting offers far shorter lead times, greater alloy flexibility (including ferrous materials which cannot be die cast), greater design flexibility, better piece to piece consistency, and produces parts closer to net shape which therefore require less machining. Tooling for lost wax casting is also dramatically less expensive than die cast tooling.

Investment Casting vs. Forging:

Compared to forging, precision investment casting offers tighter tolerances and lower tooling costs, and provides near-net shape parts which require less machining and additional processing. With investment casting, it is also possible to produce cored geometries, which forging cannot offer.

Why use forgings?

Forging offers uniformity of composition and structure. Forging results in metallurgical recrystalisation and grain
refinement as a result of the thermal cycle and deformation process. This strengthens the resulting steel product particularly in terms of impact and shear strength.

Forged steel is generally stronger and more reliable than castings and plate steel due to the fact that the grain flows of the steel are altered, conforming to the shape of the part.

The advantages of forging include:

Generally tougher than alternatives
Will handle impact better than castings
The nature of forging excludes the occurence of porosity, shrinkage, cavities and cold pour issues.
The tight grain structure of forgings making it mechanically strong. There is less need for expensive alloys to attain high strength components.
The tight grain structure offers great wear resistance without the need to make products “superhard” We have found that, on a blank HRC 38-42 forged grinder insert wear/wash is about the same as a high alloy HRC 46-50 cast grinder insert. The difference being a HRC 46-50 casting does not have the ductility to handle high impact grinding.