Explosion welding (EXW) is a solid state (solid-phase)

process A process is a series or set of activities that interact to produce a result; it may occur once-only or be recurrent or periodic. Things called a process include: Business and management *Business process, activities that produce a specific se ...

where

welding Welding is a fabrication process that joins materials, usually metals or thermoplastics, by using high heat to melt the parts together and allowing them to cool, causing fusion. Welding is distinct from lower temperature techniques such as bra ...

is accomplished by accelerating one of the components at extremely high velocity through the use of

chemical A chemical substance is a form of matter having constant chemical composition and characteristic properties. Some references add that chemical substance cannot be separated into its constituent elements by physical separation methods, i.e., w ...

explosives. This process is often used to clad carbon steel or

aluminium Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. I ...

plate with a thin layer of a harder or more

corrosion Corrosion is a natural process that converts a refined metal into a more chemically stable oxide. It is the gradual deterioration of materials (usually a metal) by chemical or electrochemical reaction with their environment. Corrosion engi ...

-resistant material (e.g., stainless steel,

nickel Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive but large pieces are slow ...

alloy,

titanium Titanium is a chemical element with the Symbol (chemistry), symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resista ...

, or

zirconium Zirconium is a chemical element with the symbol Zr and atomic number 40. The name ''zirconium'' is taken from the name of the mineral zircon, the most important source of zirconium. The word is related to Persian '' zargun'' (zircon; ''zar-gun'' ...

). Due to the nature of this process, producible geometries are very limited. Typical geometries produced include plates, tubing and tube sheets.

Development

Unlike other forms of welding such as

arc welding Arc welding is a welding process that is used to join metal to metal by using electricity to create enough heat to melt metal, and the melted metals, when cool, result in a binding of the metals. It is a type of welding that uses a welding powe ...

(which was developed in the late 19th century), explosion welding was developed relatively recently, in the decades after

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...

. Its origins, however, go back to

World War I World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...

, when it was observed that pieces of

shrapnel Shrapnel may refer to: Military * Shrapnel shell, explosive artillery munitions, generally for anti-personnel use * Shrapnel (fragment), a hard loose material Popular culture * ''Shrapnel'' (Radical Comics) * ''Shrapnel'', a game by Adam C ...

sticking to armor plating were not only embedding themselves, but were actually being welded to the metal. Since the extreme heat involved in other forms of welding did not play a role, it was concluded that the phenomenon was caused by the explosive forces acting on the shrapnel. These results were later duplicated in laboratory tests and, not long afterwards, the process was patented and put to use. In 1962, DuPont applied for a

patent A patent is a type of intellectual property that gives its owner the legal right to exclude others from making, using, or selling an invention for a limited period of time in exchange for publishing an enabling disclosure of the invention."A ...

on the explosion welding process, which was granted on June 23, 1964 under US Patent 3,137,937 and resulted in the use of the ''Detaclad''

trademark A trademark (also written trade mark or trade-mark) is a type of intellectual property consisting of a recognizable sign, design, or expression that identifies products or services from a particular source and distinguishes them from othe ...

to describe the process. On July 22, 1996, Dynamic Materials Corporation completed the acquisition of DuPont's Detaclad operations for a purchase price of $5,321,850 (or about $ million today). The response of inhomogeneous plates undergoing explosive welding was analytically modeled in 2011.

Advantages and disadvantages

Explosion welding can produce a bond between two metals that cannot necessarily be welded by conventional means. The process does not melt either metal, instead plasticizing the surfaces of both metals, causing them to come into intimate contact sufficient to create a weld. This is a similar principle to other non-fusion welding techniques, such as

friction welding Friction welding (FRW) is a solid-state welding process that generates heat through mechanical friction between workpieces in relative motion to one another, with the addition of a lateral force called "upset" to plastically displace and fuse the m ...

. Large areas can be bonded extremely quickly and the weld itself is very clean, due to the fact that the surface material of both metals is violently expelled during the reaction. Explosion welding can join a wide array of compatible and non-compatible metals, with more than 260 metal combinations possible. A disadvantage of this method is that extensive knowledge of explosives is needed before the procedure may be attempted safely. Regulations for the use of high explosives may require special licensing.

References

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Development

Advantages and disadvantages

See also

References

Further reading