Why Does forging increase strength?
Directional Strength is Key
In the forging process, controlled deformation (usually at elevated temperatures) results in greater metallurgical soundness and improved mechanical properties of the material. In most cases, forging stock has been pre-worked to remove porosity resulting from the solidification process.

How does hot forging work?
During hot forging processes, the temperature reaches above the recrystallization point of the metal being formed. ... Isothermal forging, also know as hot die forging, is a hot working process which entails the workpiece being maintained at its maximum elevated temperature throughout the entire forming process.