In most cases, forging is stronger than casting.
If we compare metal to food ingredients, casting is like "making jelly," while steel forging is like "kneading dough." Although both can create the desired shape, the internal density and impact resistance are completely different.

Here's a detailed comparison of their "strength":

1. Internal Structure's "Solidness"

Casting (making jelly): The metal is melted into a liquid and poured into a mold. During this process, air inevitably gets mixed into the liquid, or shrinkage occurs during cooling. This leads to tiny pores or looseness within the part. These invisible holes are potential weak points that can lead to future fractures.
Steel forging (kneading dough): Forging involves deforming the metal while it's still in a solid state through powerful compression. This pressure squeezes out all the air pores within the metal, making the structure extremely dense. This "solid" structure is naturally stronger than porous cast parts.

2. The Direction of "Muscle Fibers"

Casting: After the metal liquid cools, the internal particles are randomly arranged, without any directionality.
Steel forging: Forging not only changes the shape but also causes the metal's internal crystal structure to flow along the contours of the part, forming a continuous "flow line." This is similar to the muscle fibers of the human body or the grain of wood; the strength is doubled when force is applied along the grain. This unique flow line structure of steel forging allows it to perform exceptionally well when subjected to repeated vibrations and impacts.

3. Impact Resistance and Toughness

Casting: Cast parts are usually quite "brittle." When subjected to sudden, violent impact, they may shatter before they even have a chance to deform.
Forging: Forged steel has excellent toughness. When subjected to extreme pressure, it can absorb energy through slight deformation instead of breaking directly. This "toughness" is crucial for safety; for example, automotive suspension parts and critical engine components almost always require forged parts.