Casting is when metal alloy is melted and, while liquid, is poured into a mold made in the required shape, to be cooled until solid. Forging is a vastly different technique; it uses pieces of material (steel usually) and applies mechanical force to these, as well as heat, to make them softer and bendable. The alloy is malleable enough but is never in liquid state.
The advantages of casting parts
Casting has been a very reliable method of manufacturing ever since ancient times. Lost wax castings are still being used nowadays with great success. It’s simple, quick and effective: you’re making parts without any soldering or assembling and use metal only where it’s needed. The technique is employed especially in the manufacturing of small components – for the medical industry for example. By using molds, size and detail are respected with great precision. Also, it works well with large parts as long as the alloy is perfectly calibrated and presents no risk of cracking. In the manufacturing of large, heavy parts, casting is more cost efficient as well, since applying heat and pressure would be too much trouble. Besides, the method works with almost any alloy.
- If the process isn’t carefully controlled, there may be cavities or porosity in the alloy.
- Alloy composition requires more attention
The advantages of forging
Through forging, you can make sure the metal remains strong and no fissures or cracking will occur. Parts are less likely to suffer damage caused by impact. Even cheap alloys can last much longer when using this method, ideal for creating high strength components. Although it requires more mechanic work, forging creates durable and reliable parts.
- It calls for reheating the metal to be processed.
- Needs pressure to be applied until the part is ready.
In most cases, choosing between cast or forged components is not a matter of effort and budget, but a question of strength and reliability in a high stress environment. It thus depends on the application and the stress that will affect the part. Precision also plays a major role, with the casting method being the most suitable to manufacturing highly detailed and precise parts.