The history of joining metals goes back several millennia, but before the end
of the 19th century, the only process available was
forge welding, where
blacksmiths pounded heated metal repeatedly until bonding occurred. The
the first millennium B.C. knew how to heat treat steel, and it is other ancient
peoples also knew basic welding principles. Forge welding developed extensively
during the first half of the 2nd millennium AD, and in 1540, Vannoccio
Biringuccio published De la pirotechnia, which includes descriptions of
the forging operation. Craftsmen of the Renaissance era were skilled in the
process, and the industry continued to grow during the following centuries.
However, with the discovery of the
electric arc by Sir Humphrey Davy in 1801, and subsequent developments
during that century, arc welding became the most commonly used method of
metallurgically joining metals.
In 1865, an
Wilde was granted a patent for his process of melting pieces of iron
together. The electric arc did not make inroads into practical usage until 1881, with the
introduction of carbon-arc street lamps. During that decade, many developments
were made in the arc welding process, including the use of a metal electrode
(instead of carbon) and of an insulated handle that permitted manual operation
(patented by Russian scientist Nikolas de Benardos in 1887).
Additionally, two other welding process were developed during the last two
decades of the 19th
resistance welding (a group of welding processes that produce coalescence of the
faying surfaces with the heat obtained from resistance of the workpieces to the
flow of the welding current in a circuit of which the workpieces are part, and
by the application of pressure) and
oxyacetylene welding. Oxyacetylene welding at first was more popular because
of its portability and relatively low cost, but as the 20th
century progressed, it fell out of favor for industrial applications. It was
largely replaced with arc welding, as metal coverings for the electrode that
stabilize the arc and shield the base material from impurities were developed,
commonly known as flux.
World War I caused a major surge in the use of welding processes, with the
various military powers attempting to determine which of the several new welding
processes would be best. The British primarily used arc-welding, even
constructing a ship, the Fulagar, with an entirely welded hull. The Americans
were more hesitant, but began to recognize the benefits of arc welding when the
process allowed them to repair their ships quickly after a German attack in the
New York Harbor at the beginning of the war. Arc welding was first applied to
aircraft during the war as well, as some German airplane fuselages were
constructed using the process.
During the 1920s,
welding applications began slowly increasing. The application of coverings for
the metal electrodes became much cheaper in 1927 when an
extrusion process was developed, and this fed major expansion in the role of arc
welding during the
1930s and during World
War II. Major advancements in the use of automatic welding, AC current
and flux types were made during those years, and inert gases began to be used to
allow the welding of reactive metals like aluminum
This led to the creation of two commonly used processes,
gas tungsten arc welding (then known as tungsten inert gas welding) and
plasma arc welding.
The limitations of gas tungsten arc welding included the inability to weld
thick sections, and this led to the development of a consumable electrode and
ultimately gas metal arc welding, announced in 1948. During this
time, several important developments were made, such as the use of iron powder
in electrode coverings, the use of argon-helium inert gas mixtures, and
ultimately, the much cheaper use of carbon dioxide as an often satisfactory
replacement for argon and helium.
In 1958, the
flux-cored arc welding process debuted, in which the self-shielded wire
electrode could be used with automatic equipment, resulting in greatly increased
Further developments in welding have continued, but new processes (such as
laser beam welding and
electron beam welding) generally are designed for specialized applications.
Research also has shifted toward assuring that individual welds for particular
applications meet specifications.