Refined Microstructure and Directional Strength are Key Attributes

Directional strength is a direct result of the forging process. 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. This produces directional alignment (or “grain flow”) for important directional properties in strength, ductility, and resistance to impact and fatigue. These properties are deliberately oriented in directions requiring maximum strength. Working the material achieves recrystallization and grain refinement that yields the maximum strength potential of the material with the minimum property variation, piece-to-piece.

Properly developed grain flow in forgings closely follows the outline of the component. In contrast, bar stock and plate have unidirectional grain flow; any changes in contour will cut flow lines, exposing grain ends, and render the material more liable to fatigue and more sensitive to stress corrosion.