The movement of the work piece is what is key to the open die drop forging method. This method is performed between flat dies, which have no pre-cut profiles. At open die forging units in India, even parts over 200,000 lbs. in weight and 80 feet in length can be pressed or hammered into shape.
Forgings from a few pounds up to more than 150 tons can be produced in open-die forging units in India. In this process, the metal is not confined laterally by impression dies during forging, hence, earning it the name of open die. The starting stock is worked into the desired shape, between flat faced dies, in this process. Open die forging can comprise of a number of process variations. This makes for a broad range of shapes and sizes that can be produced.
The sheer size capability of open-die forging makes it the clear choice when the design criteria dictate the requirement of optimum structural integrity for huge metal components. If open-die forging units in India are limited at the high end of the size range, they are limited only by the size of the starting stock.
The shape of the open die has a wide range, and almost all forgeable non-ferrous and ferrous alloys can be open-die forged. This includes corrosion-resistant refractory alloys as well as age-hardening super alloys.
Apart from hexagonal, rectangular, square, round bars and other basic shapes, open-die processes can produce:
Step shafts and solid shafts the diameter of which increases or decreases at multiple locations along its longitudinal axis.
Hollows cylindrical shapes that usually have a length that is much greater than the diameter.
Ring-like parts depending on the required height/wall thickness ratio.
Metal shells like pressure vessels formed by contouring, which can also incorporate extruded nozzles and other design features.