(from the article `forging`) ...by hammering or pressing. In most forging an upper die is forced against a heated workpiece positioned on a stationary lower die. If the upper die ... ...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 earliest ... [... Found on http://www.britannica.com/eb/a-z/d/76