6.02 - Welding Processes and Technologies

Abstract

Welding is the joining of materials in the welding zone with the use of heat and/or force, with or without filler metal. It can be facilitated with the help of, for example, shielding gases, welding powders, or pastes. The energy required for welding is supplied from the outside. The history of welding began very early. In 4000 BC, the Sumerians already welded metals together. They welded gold with gold. It then took a very long time until the next major step in the field of welding technology was achieved. In 2700 BC, the Egyptians constructed copper lines by fire welding. The tubes were then sealed as water pipes for urban water supply. Fire welding was also used for making jewelry. In the following centuries, many important discoveries were made in the field of welding technology. The big breakthrough, however, came only during 1880–87. During this period, the Russian Nikolai Nikolaijewitsch Bernados developed what today is known as arc welding process. In the following years, this process became a very common method used for joining steel. It was used for repairing and molding metals. Several types of electrodes were also developed during 1920s. The submerged arc welding were started to be used in shipyards during 1930s. A new type of welding for welding aluminum and similar alloys known as Heliarc welding was developed in 1941. The gas shielded metal arc welding or GTAW was another significant developing in 1948. The CO2 welding process was introduced to the industry in 1953. There were several improvements in the welding industry during the 1960s. Plasma arc welding was also invented during this time. It was firstly used for metal spraying. The electron beam welding was also developed and is used by the aircraft manufacturing industries. Some of the recent developments in the welding industry include the friction welding and laser welding.