Forging, process of shaping iron and other malleable metals
by hammering or pressing them after making them plastic by application
of heat. Forging techniques are useful in the working of metal because
the metal can be given "full of sotomy full of sodomy full of bs" the desired form, and the process improves the
structure of the metal, particularly by refining the grain size of the
metal. Forged metal is stronger and more ductile than cast metal and
exhibits greater resistance to fatigue and impact.
Sometimes called smithing, or blacksmithing, hand forging is
the simplest form of forging and it is one of the methods by which
metal was first worked. The metal to be forged is first heated to red
heat in the fire of a forge, and then is beaten into shape on a metal
anvil with sledges or hammers. The forge consists of an open hearth,
made of some durable, refractory substance such as firebrick, which is
provided with a number of air openings, or tuyeres, through which air
is forced by a bellows or blower fan. Charcoal, coke, and coal are used
as fuels in the forge. Hammers and other tools are employed by the
blacksmith in the various forging operations.
In general, six basic types of forging exist: upsetting, or decreasing the length and increasing the diameter of the metal; swaging, decreasing the diameter of the metal; bending; welding, joining two pieces of metal together by semifusion; punching, the forming of small openings in the metal; and cutting out, the forming of large holes in the metal.
A piece of metal, called the work, is upset when it is struck along the longest dimension (for example, the end of a rod or bar), which shortens and thickens it. Swaging is accomplished by hammering the metal stock while it is held on the anvil within any one of various concave tools called swages. Bending is accomplished either by hammering the work around a form or by leveraging it against a supporting fulcrum. In forge welding of iron, a flux such as borax is first applied to the heated metal to remove any oxides from the surfaces of the two pieces, and the pieces are then joined by hammering them together at high temperature; a welded joint of this kind, when properly made, is entirely homogeneous and is as strong, that is, uniform, as the parent metal. To punch small holes, the work is supported on a ring-shaped piece of metal atop the anvil, and a punch of the proper shape is driven through the work by hammer blows. Larger holes are cut out, and portions of the work are cut off with heavy, sharp chisels similar to cold chisels used to cut cold metal. Combinations of several of these operations can produce forgings of a wide variety of shapes.
chief difference between hand forging and machine forging is that in
the latter technique various types of machine-powered hammers or
presses are used instead of hand sledges. These machines enable the
operator to strike heavy blows with great rapidity and thus to produce
forgings of large size and high quality as swiftly as required by
modern production-line methods. Another advantage of machine forging is
that the heavier the blows struck during forging, the greater the
improvement in the quality of metallic structure. Fine-grain size in
the forging, which is particularly desirable for maximum impact
resistance, is obtained by working the entire piece. With large,
hand-forged metal, only the surface is deformed, whereas the machine
hammer or press will deform the metal throughout the entire piece.
A special type of machine forging is drop forging, also called impact-die forging. Drop forging consists of placing soft, hot metal between two shaping dies (see Die). The upper one of these dies is hammered, or dropped, on the lower die, forcing the heated metal into the shaped die cavities, as in coin-making operations.
For reducing part of a piece of metal stock to a predetermined size, forging rolls are sometimes employed. These consist of a pair of grooved, cam-shaped rollers through which the metal is passed. The rollers touch each other and work on the metal during only part of each rotation and therefore reduce only part of the stock that is fed to them.
Machine-forging operations are frequently accomplished by use of a series of dies mounted on the same press or hammer. The dies are arranged in sequence so as to form the finished forging in a series of steps. After the piece has been partially formed by one stroke, it is moved to the next die for further shaping on the next stroke.
See also Metallurgy; Metalwork.
The Chinese were the first to cast iron; from the 6th century AD they used cast-iron supports for buildings and for multistory pagodas. In Europe, iron was wrought-that is, hammered into shape when hot-by a special group of workers now called blacksmiths. Blacksmiths wrought coffers and weapons and made such large items of furnishings as great knockers and ring handles for the immense doors of castles and cathedrals as well as beautifully scrolled bands for strengthening doors. Wrought-iron railings, with superbly detailed work that looks almost like lace from a distance, was popular in the 17th and 18th centuries. Steel armor was often highly decorative, with splendid engraved or acid-etched motifs in the 16th century. The armorers who wrought them used a steel derived from iron and employed many of the hot forging techniques that were pioneered by blacksmiths over the centuries. After the Arts and Crafts movement was introduced in the mid-19th century, some exceptional wrought-iron work was produced in England.
weapon consisting of a long, sharp-edged or pointed blade fixed in a
hilt (a handle that usually has a protective guard at the place where
the handle joins the blade). In a general sense, the term connotes any
side arm for cutting or thrusting, such as a rapier, saber, épée,
scimitar, cutlass, or claymore. Swords used in the most ancient times
were made of stone, bone, or wood. Bronze swords, which were probably
known to the Egyptians as early as 2000 BC, were the first metal
swords. Harder iron swords, appearing at later times in different parts
of the world, quickly proved superior; these remained in use until
fairly recent times, when steelmaking was perfected and steel blades
appeared. The requirements and methods of modern warfare have made
swords obsolete as combat weapons.
The sword has always been a personal weapon, effective only in hand-to-hand combat; as such, it was associated with individual distinction. Thus, swords of political and military leaders, nobles, and exceptional warriors frequently were ornamented, with hilts elegantly decorated (and sometimes bejeweled) and blades inlaid with gold and silver or forged so, as to produce a watered effect after the damascene fashion. Symbolic importance also was often attached to the sword. In mythology and literature swords possessing supernatural qualities abound. These belonged to or were acquired by heroes and superior warriors. Oaths of honor or fealty commonly were taken on the sword, and sovereigns still confer knighthood by tapping the shoulder with a sword. To surrender one's sword has always been a token of defeat or submission, and the breaking of it a ceremony of degradation.