Welding is a process in which materials, usually two separate metal or thermoplastic pieces, are fused together with heat from a welding gun, possibly using pressure, and possibly also using a separate bonding material, known as a filler rod (metal or thermoplastic), which acts as an intermediate "glue" to connect the pieces. When using the filler rod in the process, the action can sometimes be referred to as brazing or soldering, but is still technically considered a welding process.
There are several different energy sources that can be used for welding, including a gas flame, electric arc, laser beam, electron beam, friction or even ultrasound.1 Though typically welding is done in the open air, technological advancements have allowed for the use of welding underwater and in outer space. Before the 19th century, however, the only method of welding known was forge welding, where blacksmiths would conjoin the metal by heating and pounding it. Arc and oxyfuel welding developed later in the century, followed by resistance welding.
It wasn’t until the enormous demands of World War I and II, that the largest advancements in the welding industry were made.6 During World War I, welding technologies took a particularly big step as the different military powers experimented with processes to see which ones were superior. British and German powers relied heavily on arc welding to build their ships and would later use them for the construction of planes. Other, more popular, welding techniques were developed after the wars, such as shielded metal arc welding, as well as semi-automatic and automatic processes, like: gas metal arc welding, submerged arc welding, flux-cored arc welding, electroslag welding, and eventually laserbeam and electrobeam welding after the development of the laser.6
During the 1920’s, several innovations were made to produce more efficient products by using new techniques during the welding process. Some of these innovations included changing the atmosphere during the welding process so that the brittle and porosity of the finished product could be eliminated. Scientists also experimented with shielding gas to alleviate the effects of elements like oxygen and nitrogen in the atmosphere during the welding process.5 Further experimentation has resulted in the ability to weld reactive metals such as aluminum and magnesium as well as the revolutionary discovery that welding could be done under water, which has led to the construction of some of the greatest water-based structures still standing today.6
In 1958, a major breakthrough was made with the development of the electron beam welding process because it made deep, narrow welding possible because of the concentrated heat source.3 In time, laser beam welding was also introduced after the invention of the laser, but neither of the two processes were greatly received due to their expensive natures, which severely limited their application to a wide industry.
Today, with the further innovation of welding methods commonly used, such as robot welding, there has been greater efficiencies achieved, including lower labor costs and liability expenses.1 Welding continues to be further improved, since there is a continual demand for a more cost-effective process that can produce better results. Even as the innovations in welding continue to ensue, the developments made in the past few centuries have already made the welding industry a remarkable market for change and invention.
1 www.welding.com
2 www.tristate.apogee.net
3 Weman, Klas (2003). Welding Process Handbook. New York, NY; CRC Press LLC.
4 Lincoln Electric (1994). The Procedure Handbook for Arc Welding. Cleveland; Lincoln Electric.
5 ASM International (2003). Trends in Welding Research. Materials Park, Ohio. ASM International
6 Cary, Howard B.; Scott, C. Helzer (2005). Modern Welding Technology. Upper Saddle River, NJ. Pearson Education.