Forging is a method that involves what main process?

Forging is a manufacturing process that primarily involves heating metal and then shaping it through the application of force, typically using a hammer or a forging press. This process enhances the metal's strength and structural integrity through deformation while it is in a plastic state, which occurs at elevated temperatures. The resulting products are often stronger than those achieved through other manufacturing methods because the grain structure of the metal is refined and aligned, improving its mechanical properties.

In this context, the act of heating is crucial because it makes the metal malleable enough for shaping, while the hammering or pressing provides the force required to mold the metal into the desired form. This is why the correct response emphasizes both heating and hammering as the defining aspects of forging. The other methods listed, such as cooling metal, welding, and melting and casting, pertain to different manufacturing techniques and do not capture the essence of forging, which is fundamentally about deformation through heat and mechanical force.