What is Open Die Forging?
The process of Open Die Forging is done to make parts that are too big to be formed in a closed die or in cases where only a few parts are to be made and the cost of a die is therefore unjustified. The process is undertaken by hammering a part between two flat faces. Earlier the technique employed large hammers that were lifted and then dropped on the work, but now air- or steam-driven hammers are used. This is because these allow greater control over the force and the rate of forming. In between the blow, the part is shaped by moving or turning. A forged ring can be formed by placing a mandrel through the ring and deforming the metal between the hammer and the mandrel.