Upset forging involves increasing the diameter of a work piece by compressing its length. Upset forging is the most widely used forging process based simply on the number of pieces produced. Fasteners, screws, bolts, couplings and engine valves are a few examples of common parts that can be produced at upset forging units in India.
Usually done with crank presses, special high-speed machines, upset forging can also be done in vertical crank presses or hydraulic presses. To facilitate the quick exchange of work pieces from one station to the next, the machines are usually set up to work in the horizontal plane. Normally, an upsetting machine uses split dies containing multiple cavities.