New shape of forging ingot for making hollow forged products

Replacement of the conventional hot top — which accumulates heat from the melt inside an ingot mold — by a cooling element that is also placed on top of the mold has made it possible to obtain ingots with a narrow primary shrinkage cavity that extends along their axis. Such ingots are well-suited for the production of hollow forgings. When a standard hot top is used, the transverse dimensions of the region of the ingot affected by axial porosity correspond to as much as 15% of the ingot’s diameter. The same region accounts for just 8.5% of the ingot diameter when the above-mentioned cooling element is used instead. This makes it easier to remove the defective region by piercing or drilling it out during the forging conversion.