Forgings
Forging companies work with a broad range of metals to create all sorts of metal forgings, including aluminum forgings, brass forgings, copper forgings, titanium forgings, alloy forgings, stainless steel forgings, carbon steel forgings, and nickel forgings. Closed die forging and open die forging are the two primary types of forging, while drop forging, press forging, roll forging, hand forging, hot forging, warm forging and cold forging refer to various forging methods. Because forging produces the strongest and most reliable metal products available, forgings are frequently used as components where reliability and human safety are imperative, such as in airplanes, automobiles, tractors, ships, material handling equipment, engines, tools, missiles and much more. Industries that make frequent use of forgings include aerospace, national defense, automotive, agriculture, construction, mining and general industrial equipment.
Closed die forging, also known as impression die forging, involves the pressing or hammering of preformed metal blanks, or ingots, into a die or set of dies shaped as a three dimensional negative of the part to be produced. In this type of forging the hammer and anvil fully enclose the workpiece, forcing the metal to fill all areas of the die. Closed die forging is the more common forging method, since it can produce a nearly limitless variety of 3-D shapes, and is capable of producing complex parts with tight tolerances. Often, closed die forging requires that the workpiece be moved through a series of impression cavities, first forming the rough shape, then proceeding until a finisher cavity turns out the final product. Open die forging, on the other hand, uses simply-shaped (flat, concave or convex), non-encompassing dies to hammer or press a metal workpiece into a certain shape. The product usually requires numerous strikes or presses to take on its intended shape, so an operator must repeatedly reposition and orient the workpiece so that the die will fall successively on the next side or section of the workpiece. Open die forging is used to produce a large variety of forms such as round, rectangular and hexagonal bars, beams, profiles and other more basic shapes. Since tooling tends to be simpler and lower in cost, open die forging is better suited for lower volume production and creation of unique items. Ring rolling is a distinctive type of open die forging used to produce seamless rolled rings. It involves forming a donut-shaped piece of metal into a seamless cylindrical or ring shape by turning it and simultaneously exerting pressure on the inner and outer dimensions of the ring. Drop forging refers to any forging process that operates by bringing down a large machine-operated hammer.
Forgings can be produced in three different temperature zones. Hot forging is the most common and is done at temperatures as high as 2300°F, above the re-crystallization point of the metal but below its melting point. Warm forging is done above room temperature but below the re-crystallization temperature of the metal, up to several hundred degrees. Cold forging is done at ambient temperatures. The cold forging process is only possible with certain metals and relatively small workpieces, usually 10 pounds or less; but it 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. Warm forging has many of the advantages of cold forging, while slightly broadening the selection and size of metals that can be used. Hot forging is the most versatile method in terms of the size of parts it can produce, from a few ounces to over 25 tons, and in terms of the range of metals that can be forged. Hot forged items are also easier to subject to secondary processing and machining.
Forgings of different metals can have different benefits. Aluminum is easy to forge and has a good balance of low weight and high strength. Copper forgings have good conductivity while maintaining non-magnetic and non-sparking properties. Titanium has a high material cost but offers an excellent strength-to-weight ratio and resistance to corrosion. Carbon steel forgings provide good mechanical properties for a relatively low material cost, and respond well to heat treatment. Stainless steel has the properties of steel but adds corrosion-resistance. Nickel alloy forgings resist oxidation and are exceptionally stable at high temperatures. Regardless of the metal, however, forgings provide a cost-efficient alternative to casting, welding and fabrication. Forgings are extra strong, offer great design flexibility, require few secondary operations, produce a broad part size range and usually have very few defects. Due to the lack of internal gas pockets in forged products and materials, there is very little unexpected failure. The forging process is highly customizable, but can also produce consistent, repeatable results from part to part. All of these factors make forgings the safest, most economical and most effective metal components for many industrial applications.
| Forgings and Cold Forging Images Provided by Clifford-Jacobs Forging Company |
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Forgings and Cold Forging Images Provided by Weldaloy Products Company |
Forging Types
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contain steel and alloys, such as nickel, to produce desired properties. These steel alloys do not contain carbon.
- are easy to forge, possess a smooth appearance, good fracture resistance and great electrical conductivity and are economical.
- uses a metal flow moving in a direction away from a common axis in a radial direction during deformation.
- are common in the hardware industry, producing useful and decorative parts, such as valves, doorknobs and handles.
- are cost-effective, easy to manufacture and effective in temperatures up to 900°F (482°C).
- is the shaping of hot metal completely within the walls or cavities of two dies that come together and enclose the workpiece on all sides.
- are produced at temperatures ranging from room temperature to a few hundred degrees. Consisting of alloys of steel and aluminum, among others, cold forgings are common in the production of industrial parts that have intricate features, such as suspension components and steering parts in automotive equipment.
- , such as automotive forgings and electrical fittings, are used in the semiconductor process equipment, material processing and hydro-dynamic bearings market segments because of their high corrosion resistance and good conductive properties.
- is a process in which a press containing two opposing rams hits a blank at the same time.
- works forging stock in alternate planes, usually on flat dies, to develop mechanical properties.
- are designed to be cut apart and used as two separate pieces.
- are made in closed or impression dies under a drop or steam hammer.
- is a process in which a ram strikes a workpiece on an anvil.
- is a process in which dies are heated close to the forging temperature of the alloy being forged; used for difficult-to-forge alloys.
- are formed to the specific shape and size by machined impressions in specially prepared dies that exert three-dimensional control on the workpiece.
- (upsetter forging) is the process of forging in a machine (upsetter), in which metal is moved into the die impression by pressure applied in a horizontal direction by the moving die in the ram.
- have a lower density than other metals. Magnesium forgings can also withstand operational temperatures up to 500°F (280°C).
- is the process of forging and rolling a hollow blank over a mandrel in order to produce a weldless, seamless ring or tube.
- Metal forging is a metal forming process that involves the plastic deformation of metal through extreme pressure and, for the most part, high temperatures.
- are resistant to oxidation and can withstand temperatures up to 1800°F (982°C).
- are forgings produced by working between flat or simply contoured dies with unrestricted metal flow using repetitive strokes and continuous manipulation of the workpiece; sometimes called hand forging.
- is a forging produced to closer tolerances than normally considered standard by the industry.
- round metal blanks in which a doughnut hole is punched . The ring is then thinned out through rolling and stretching operations.
- contain 10-12% chromium and provide great corrosion resistance to a variety of structures, such as pressure vessels, turbines and boilers, in temperatures ranging up to 1800°F (982°C) or higher.
- produce strong, low-density parts similar to steel, but lighter. Titanium is particularly useful in the construction of parts in the aerospace industry.
- is a process in which the metal is gathered at the middle or one or both ends, producing plastic deformation of the metal.
Forging Terms
The condition of a forging as it comes out of the finisher cavity without any added operations.
- A process in which the metal flows in the opposing direction of the die and punch.
- A metal piece that is hot rolled from a billet to form a round, hexagonal, square or rectangular shape.
- Lengthwise deformation that occurs during forging or secondary operations, such as trimming.
- A semi-finished, usually hot-rolled, uniform section metal product. Billets are relatively larger than bars for the most part. - The forging operation in which metal is progressively formed to general desired shape and contour by means of an impression die.
- A semi-finished product of square or round cross section. This term is sometimes used interchangeably with "billet.""
- A type of gravity drop hammer in which wood boards attached to the ram are raised vertically by action of contra-rotating rolls, then released. Forging energy is produced by the mass and velocity from the freely falling ram and the attached upper die. - The recess in a die that gives shape to the forging. Cavities are typically created by machining.
- A sizing process in which pressure is applied to forged parts to smooth part surfaces and fix deformations.
- Changing properties, such as size, shape and strength of an alloy, through plastic deformation of the metal at low to moderate temperatures below the recrystallization point of the metal.
- Part of press that punches shaped holes in, cuts or forms sheet metal.
- External and internal imperfections of a forging. External discontinuities include cracks, folds and laps; internal discontinuities include porous and segregated deformations.
- The formation of a hole or the enlargement of an existing hole in a forging through punching.
- The amount of applied energy that is utilized in the deforming of the workpiece, expressed as a percentage of the total energy expended by the forging equipment.
- The process of forcing metal to flow through a die opening in the same direction in which energy is being applied. Extrusion is used in many die-forging applications.
- Excess metal that extends past the parting line of the die set, blocking metal from flowing past the die lines and filling the die impressions.
- The measurement of the deformation resistance of a substance dependent on such factors as temperature.
- The mechanism on a press to which the punch is fastened and that forces the punch through the die.
- Secondary operation in which a forging is cut down to desired shape and size by removing flash from the forging.
- Forging deformation that occurs along the width of the forging.
