Ring rolling is a hot forming process that produces seamless rings varying in size. It begins with a hollow circular preform that has been upset and pierced. The preform is placed over the idler or mandrel roll, which is forced toward the drive roll. The drive roll rotates continuously, reducing the wall thickness, imparting the desired shape to the cross section, and increasing the diameter.
Rolling is continuous forming of metal between a set of rotating rolls whose shape or height is incrementally reduced to produce desired section through imposing high pressures for plastic deformation. It is the process of reducing thickness, increasing length without increasing the width markedly. The ring rolling process can be performed with the material at high temperature. Ring rolling is an advanced technique to manufacture seamless rings with flexible cross-sectional shape, improved grain structure, and minimal scrap.
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. 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.
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.
