Is weld stronger than steel?

The Middle Ages brought advances in forge welding, in which blacksmiths pounded heated metal repeatedly until bonding occurred. In 1540, Vannoccio Biringuccio published De la pirotechnia, which includes descriptions of the forging operation. Renaissance craftsmen were skilled in the process, and the industry continued to grow during the following centuries. In 1800, Sir Humphry Davy discovered the short-pulse electrical arc and presented his results in 1801. In 1802, Russian scientist Vasily Petrov created the continuous electric arc, and subsequently published "News of Galvanic-Voltaic Experiments" in 1803, in which he described experiments carried out in 1802. Of great importance in this work was the description of a stable arc discharge and the indication of its possible use for many applications, one being melting metals. In 1808, Davy, who was unaware of Petrov's work, rediscovered the continuous electric arc. In 1881–82 inventors Nikolai Benardos (Russian) and Stanisław Olszewski (Polish) created the first electric arc welding method known as carbon arc welding using carbon electrodes. The advances in arc welding continued with the invention of metal electrodes in the late 1800s by a Russian, Nikolai Slavyanov (1888), and an American, C. L. Coffin (1890). Around 1900, A. P. Strohmenger released a coated metal electrode in Britain, which gave a more stable arc. In 1905, Russian scientist Vladimir Mitkevich proposed using a three-phase electric arc for welding. Alternating current welding was invented by C. J. Holslag in 1919, but did not become popular for another decade.

GTAW can be used on nearly all weldable metals, though it is most often applied to stainless steel and light metals. It is often used when quality welds are extremely important, such as in bicycle, aircraft and naval applications. A related process, plasma arc welding, also uses a tungsten electrode but uses plasma gas to make the arc. The arc is more concentrated than the GTAW arc, making transverse control more critical and thus generally restricting the technique to a mechanized process. Because of its stable current, the method can be used on a wider range of material thicknesses than can the GTAW process and it is much faster. It can be applied to all of the same materials as GTAW except magnesium, and automated welding of stainless steel is one important application of the process. A variation of the process is plasma cutting, an efficient steel cutting process.

High-production applications have made energy beam welding a very popular process. They are almost identical, but they differ in the source of their power. The laser beam welding process uses a very focused laser beam. While electron beam welding uses an electron beam and is performed in a vacuum, it employs a concentrated laser beam. Both have very high energy densities which allow for deep penetration of the weld and reduce the size of the weld area. Both are highly productive and fast. They are susceptible to thermal cracking and have high equipment costs. This area has seen many developments, including laser-hybrid welds, which combine principles of both laser beam welding with arc welding for better weld characteristics, laser cladding and xray welding.

Another common process, explosion welding, involves the joining of materials by pushing them together under extremely high pressure. The energy from the impact plasticizes the materials, forming a weld, even though only a limited amount of heat is generated. The process is commonly used for welding dissimilar materials, including bonding aluminum to carbon steel in ship hulls and stainless steel or titanium to carbon steel in petrochemical pressure vessels. Like spot welding, seam welding relies on two electrodes to apply pressure and current to join metal sheets. However, instead of pointed electrodes, wheel-shaped electrodes roll along and often feed the workpiece, making it possible to make long continuous welds. In the past, this process was used in the manufacture of beverage cans, but now its uses are more limited. Other resistance welding methods include butt welding, flash welding, projection welding, and upset welding.

The 1958 invention of electron beam welding made it possible to do deep and narrow welding using a concentrated heat source. Laser beam welding was created in 1960 and proved extremely useful for high-speed, automated welding. Since 1967, magnetic pulse welding (MPW), has been used in industry. Wayne Thomas, The Welding Institute (TWI) in the UK invented friction stir welding. It has been used worldwide for high-quality applications. These four new processes are still quite costly due to the high price of the equipment. This has restricted their use. Oxfuel welding is the most popular gas welding process. Also known as oxyacetylene weld. Although it is the most common and oldest type of welding, it has been less popular in recent years for industrial applications. It's still used extensively for welding tubes and pipes, as well as repairs.