Historical Development of Welding

Welding, which is one of the newer metalworking trades, can trace its historic development back to ancient times. The earliest example comes from the Bronze Age. Small gold circular boxes were made apparently by pressure welding lap joints together. It is estimated that these boxes were made more than 2,000 years ago and are presently on exhibit at the National Museum in Dublin, Ireland.

During the Iron Age it appears that the Egyptians and other people in the Eastern Mediterranean area learned to weld pieces of iron together. Many tools and weapons have been found which were apparently made approximately 1000 B.C. Items of this type are on exhibit in the British Museum in London. Other examples of early welded art are displayed in the museums of Philadelphia and Toronto. Items of iron and bronze that exhibit intricate forging and forge welding operations have been found in the pyramids of Egypt.

During the Middle Ages the art of blacksmithing was developed to a high degree and many items of iron were produced which were welded by hammering. One of the largest welds from this period was the Iron Pillar of Delhi in India, which was erected about the year 310 A.D.

Sir Humphrey Davies of England is credited with providing a foundation for modern welding with two of his discoveries. One was the discovery of acetylene and the second was the production of an arc between two carbon electrodes using a battery. In the mid-1800s, the electric generator was invented and arc lighting became popular.

The period of 1877 to 1903 provided a great number of discoveries and inventions pertaining to welding. During this period gas welding and cutting were developed. Arc welding with the carbon arc and metal arc was developed and resistance welding, much as it is known today, became a practical joining process.

This work was the actual beginning of arc welding or at least carbon arc welding. Benardos’ efforts were apparently all restricted to carbon arc welding, although he was able to weld iron as well as lead. Carbon arc welding became increasingly popular during the late 1890s and early 1900s.

Apparently Benardos was not successful with a metallic electrode, and in 1892 C.L. Coffin of Detroit was awarded the first U.S. patent for an arc welding process using a metal electrode. This was the first record of the metal melted from the electrode actually carried across the arc to deposit filler metal in the joint to make a weld. At about the same time, N. G. Slavianoff, a Russian, presented the same idea of transferring metal across an arc, but to cast metal in a mold.

In about 1900 Strohmeyer introduced a coated metal electrode in Great Britain. There was a thin wash coating of clay or lime, but it did provide a more stable arc. Meanwhile, the resistance welding processes were developed, including spot welding, seam welding, projection welding, and flash butt welding. Professor Elihu Thompson is given credit for originating resistance welding. Thermit welding was invented by a German named Goldschmidt in 1903 and was used to weld railroad rail.

Gas welding and cutting were also perfected in this same period. The production of oxygen, and later the liquefying of air, along with the introduction in 1887 of a blow pipe or torch, helped the development of both welding and cutting. Before 1900 hydrogen and coal gas were used with oxygen. However, in about 1900 a torch suitable for use with low-pressure acetylene was developed and the oxyacetylene gas welding and cutting processes were launched.

During the period of about 1900 to 1918, the oxyacetylene welding and cutting process plus the carbon arc welding and metal arc welding process with lightly covered electrodes were used primarily for repair and maintenance work.

World War I brought a tremendous demand for metal material production, and welding was pressed into service. Many companies sprang up in America and in Europe to manufacture various types of welding machines and electrodes to meet this requirement.

Immediately after the war, in 1919, twenty members of the Wartime Welding Committee of the Emergency Fleet Corporation, under the leadership of Comfort Avery Adams, founded the American Welding Society. It was founded as a nonprofit organization dedicated to the advancement of welding and allied processes.

In 1920, automatic welding was introduced. It utilized bare electrode wire operated on direct current and utilized arc voltage as the basis of regulating the feed rate of the electrode wire. It was used to build up worn motor shafts and worn crane wheels. It was also used by the automobile industry to produce rear axle housings.

During the 1920s various different grades and types of welding electrodes were developed and made available. Mild steel or low carbon steel, usually with a carbon of 0.20% or less, was used for welding practically all grades of rolled steel. Higher carbon electrodes and alloy steel electrodes were also developed. Copper alloy rods were developed for carbon arc welding and brazing.

There was considerable controversy during the 1920s about the advantage of the heavy-coated rods versus light- or wash-coated rods. Heavy-coated rods made by dipping were more expensive. Coating applied by extrusion on the rod was less expensive.

During the 1920s there was considerable interest in shielding the arc and weld area by externally applied gases. It was realized that the atmosphere of oxygen and nitrogen in contact with the molten weld metal caused brittle and sometimes porous welds. In view of this, research work was done to utilize gas-shielding techniques. They utilized two electrodes starting with carbon electrodes but later changing to tungsten electrodes.

The hydrogen was changed to atomic hydrogen in the arc. It was then blown out of the arc forming an intensely hot flame of atomic hydrogen burning to the molecular form and liberating heat. This arc produced half again as much heat as an oxyacetylene flame. This was named the atomic hydrogen welding process. Atomic hydrogen never became extremely popular but was used during the 1930s and 1940s for special applications of welding and later on for welding of tool steels.

The covered electrode became the mainstay of the welding industry, even though it was applied manually. At the same time many efforts were made to improve automatic welding utilizing bare wire. Such efforts included the use of a covering on electrodes which were then coiled and at the welding point the coating was milled away to introduce welding current to the core wire.

One of the more specialized welding processes was developed in 1930 at the New York Navy Yard. This process, known as stud welding, was developed specifically for attaching wood decking over a metal surface. The process welded studs, screws, etc., to the base metal by means of a special gun, which automatically controlled the arc. Fluxing elements on the end of the stud improved the properties of the weld. Stud welding became popular in the shipbuilding and construction industries and in manufacturing.

The automatic process that became extremely popular was the submerged arc welding process. This "under powder" or smothered arc welding process was developed by the National Tube Company for a new pipe mill at McKeesport, Pennsylvania. It was designed to make the longitudinal seams in the pipe. Submerged arc welding was used during the defense buildup in the late 1930s and early 1940s in both the shipyards and in ordnance factories. It is one of the most productive welding processes and remains popular today.

Gas tungsten arc welding had its beginnings from an idea by C.L. Coffin to weld in a nonoxidizing gas atmosphere, which he patented in 1890. The concept was further refined in the late 1920s by Hobart, when he used helium for shielding, and Devers, who used argon.

The other concept invented by Hobart and Devers was the gas shielded metal arc welding process successfully developed at Battelle Memorial Institute in 1948 under the sponsorship of the Air Reduction Company. This development utilized the gas-shielded arc similar to the gas tungsten arc, but replaced the tungsten electrode with a continuously fed electrode wire.

In 1953 Lyubavskii and Novoshilov announced the use of welding with consumable electrodes in an atmosphere of CO₂ gas. The CO₂ welding process immediately gained favor since it utilized equipment developed for inert gas metal arc welding but could now be used for economically welding steels. The CO₂ arc is a hot arc and the larger electrode wires required fairly high currents. Efforts were made to make the process more acceptable for the welder and this in turn led to smaller diameter electrode wires and refined power supplies.

Another variation was the use of inert gas with small amounts of oxygen which provided the spray-type arc transfer. This variation became popular in the early 1960s for welding agricultural equipment. The latest variation of gas metal arc welding is the use of pulsed current.

Soon after the introduction of the CO₂ welding process a variation utilizing a special electrode wire was developed. This wire, described as an inside-outside electrode, was tubular in cross section with the fluxing agents on the inside. These wires could be used in the same equipment as the gas metal arc welding process.

The plasma arc welding process, which is very similar to gas tungsten arc welding, was invented by Robert Gage in 1957. Plasma arc welding uses a constricted arc or an arc through an orifice, which creates an arc plasma that has a higher temperature than the tungsten arc. It is also used for metal spraying and for cutting. As a cutting process it became popular for nonferrous metals. It is used for spraying both wires and powders. Plasma arc welding is popular for low-current welding and is becoming increasingly popular in higher-current applications.

The electron beam welding process, which uses a focused beam of electrons as a heat source in a vacuum chamber, was developed in Germany and France. The Zeiss Company and the French Atomic Energy Commission are credited with developing the process in the late 1940s. In the last few years the process has gained widespread acceptance for welding. Its popularity is increasing since recent developments have allowed it to be taken out of the vacuum chamber which was its major disadvantage. More and more applications are being found for this process, which should grow in popularity in the future.

Friction welding, which uses high rotational speeds and upset pressure to provide friction heat, was developed in the Soviet Union, but additional work was done in Great Britain and the USA. It is a specialized process and has applications only where a sufficient volume of similar parts are to be welded because of the initial expense of equipment and tooling. This process, also called inertia welding, will find more uses and will become more popular.

A more recent welding process is laser welding. The laser originally developed at the Bell Telephone Laboratories was used as a communications device. Because of the tremendous concentration of energy in a small space it proved to be a powerful heat source. It has been used for cutting metals and other materials. The early problems involved short pulses of energy; however, today continuous pulse type equipment is available. The equipment is still extremely expensive and bulky, but in time it should be reduced in cost and size. The laser is now finding welding applications in routine metalworking operations.

There are many other variations of these processes, which are not specifically processes themselves. These will be discussed along with the basic process. Undoubtedly, additional welding processes and methods will be developed and as the need arises they will be adapted to metalworking requirements.