Metal forming
Forging vs Casting
Forging shapes solid metal under force, aligning the grain for strength; casting pours molten metal into a mold for complex shapes. Strength and integrity versus geometric freedom.
| Forging | Casting | |
|---|---|---|
| Metal state | Solid, deformed under force | Molten, poured into a mold |
| Grain structure | Aligned, continuous | As solidified, can be porous |
| Strength | Highest, no internal voids | Good, depends on process |
| Geometry | Limited, simpler shapes | Complex, near net shape |
| Tooling cost | High for dies | Low to moderate |
| Porosity risk | Very low | Possible, mitigated by process |
| Best use | Highly loaded critical parts | Complex or large parts |
Choose Forging when
- Parts under high or cyclic load where strength is critical
- You need maximum fatigue resistance and no porosity
- Simpler geometry that a die can form
Choose Casting when
- Complex geometry or internal passages
- Large parts or lower tooling budgets
- Strength requirements are moderate
The verdict
Forge parts that carry high or cyclic loads and cannot tolerate porosity, and cast parts whose geometry is too complex to forge or where tooling budget and part size favor pouring.
Cost comparison
Forging dies commonly run 20,000 to 100,000 USD or more against much cheaper casting patterns, and forged blanks usually need machining on every functional face. Castings often cost less per part at the same volume. Forging pays for itself when the casting alternative would need thicker sections, added ribs, or post-processing to meet the same fatigue and integrity requirements.
Common questions
Is forging stronger than casting?
Yes. Forging aligns the metal grain and eliminates internal voids, giving higher strength and fatigue resistance than casting, which can contain porosity.