Metal forging is a metal forming process that involves the plastic deformation of metal through extreme pressure. Usually metal forging is performed at high temperatures, but it can also be done ‘cold’ at temperatures below the re-crystallization point of the metal. As one the oldest known metalworking processes, metal forging has evolved over the centuries to include innovative and diverse techniques.
Some of the more recently developed metal forging techniques include induction forging, impression-die forging, press forging and roll forging. Some of the metals that are commonly used in metal forging processes include aluminum, iron, carbon steel, copper, titanium, brass, stainless steel and nickel.
Metal forging is used to produce an extensive amount of parts and products including blanks, gears, bars, springs, hubs, spindles, flanges, shafts, rings, pins, axles and piping.
Since metal forging is used to form so many different kinds of parts, it is applicable for a wide range of industries such as electronics, industrial, automotive, construction, aerospace, mining, medical and architecture. In addition, metal forging is advantageous over other metalworking processes because it provides enhanced strength characteristics in the produced parts.
The two most common methods of metal forging are closed or open die forging. Closed die, or impression-die, forging involves the movement of metal blanks through a set of dies shaped in the required part design. Open die forging, also known as smith forging, involves the use of flat dies with little shape. This method creates parts by the manipulation of the metal through the die into the required shape.
This process allows for larger products to be forged and is more amenable to small production runs and one-of-a-kind items than closed-die forging. In addition, metal forging can also be done in three different temperature zones. Hot metal forging is the most common and is done at temperatures up to 2300 degrees F.
Cold forging and warm forging, on the other hand, are done at temperatures ranging from room temperature to several hundred degrees, depending on the metal.
The cold forging process is only possible with relatively small workpieces, up to 25 pounds, but has the benefit of producing even stronger products because of the work hardening that takes place during the forging. Cold forging processes include bending, cold drawing, cold heading, coining and extrusions.
Hot forging has its advantages over cold forging as well; it is more versatile in terms of the sizes of its products and in terms of the range of metals that can be forged. Hot forged items are also more easily subjected to further processing and machining.
Metal Forging Informational Video