Disc forgings, also called forged discs or plate forgings, are a component made by forging (thickening or lengthening) the heated materials on the forging equipment. Through thickening, the height of the materials is reduced and the diameter is increased. The internal fiber line is transferred from being horizontal with the axis to being radial with it. The metal grains are also refined and improved in this process. Therefore, compared to discs cut from plates or rods, forged discs have greater hardness, toughness, impact strength and fatigue resistance.