Open Die Forging

Open-die forging is also known smith forging. In open-die forging, a hammer strikes and deforms the workpiece, which is placed on a stationary anvil. Open-die forging gets its name from the fact that the dies (the surfaces that are in contact with the workpiece) do not enclose the workpiece, allowing it to flow except where contacted by the dies. Therefore the operator needs to orient and position the workpiece to get the desired shape.

The dies are usually flat in shape, but some have a specially shaped surface for specialized operations. For example, a die may have a round, concave, or convex surface or be a tool to form holes or be a cut-off tool. It is different from closed die forging in that the workpiece is not enclosed by the dies and the dies themselves are more like tools with simple shapes and profiles rather than resembling enclosed molds.

Open die forging is an important technique for many types of manufacturing. It allows rough and finishing shaping of metal, most commonly steel and steel alloys. It requires a die that is open on the sides, allowing the workpiece to move freely, in a lateral direction, when struck. This type of design also allows for forging of very large workpieces, in some cases, weighing many tons and having great length and width.

Open die forgings can be worked into shapes which include discs, hubs, blocks, shafts (including step shafts or with flanges), sleeves, cylinders, flats, hexes, rounds, plate, and some custom shapes.

Advantages:

• Reduced chance of voids
• Better fatigue resistance
• Improved microstructure
• Continuous grain flow
• Finer grain size
• Greater strength