Swords made in the Warring States period have steel blades and wrought iron backs, which are generally made by heating forging and welding. According to the book Tiangong Kaiwu written by Song Dynasty in Ming Dynasty, in ancient China, copper and iron were heated together in a furnace and forged into knives and axes. Sprinkle yellow mud or sifted old wall soil on the joint, and forge and weld the big anchor in sections. In the Middle Ages, Damascus, Syria also made weapons by forging and welding.
Ancient welding technology has long remained at the level of casting welding, forging welding and brazing. The heat source used is fire, the temperature is low and the energy is not concentrated. It can't be used to weld workpieces with large sections and long welds, but can only be used to make decorations, simple tools and weapons. /kloc-At the beginning of the 0/9th century, Davis in Britain discovered two kinds of high-temperature heat sources that can partially melt metals: electric arc and oxyacetylene flame. From 1885 to 1887, Russian Benado invented the carbon electrode arc electrode holder; 1900, thermite welding appeared again.
At the beginning of 20th century, carbon electrode arc welding and gas welding were applied, and covered electrode arc welding with thin coating appeared at the same time. The arc is relatively stable, the molten pool is protected by slag, and the welding quality is improved, which makes manual arc welding enter the practical stage. Since the 1920s, arc welding has become an important welding method.
During this period, Noble Company of the United States used arc voltage to control the feed speed of covered electrode, and made an automatic arc welding machine, which became the beginning of welding mechanization and automation. 1930, Robinov of the United States invented submerged arc welding of welding wire and flux, and the welding mechanization was further developed. In the 1940s, in order to meet the needs of welding aluminum, magnesium alloy and alloy steel, tungsten electrode and metal inert gas came out one after another.
195 1 year, the Barton electric welding research institute of the Soviet Union created electroslag welding, which became an efficient welding method for thick workpieces. 1953, Lyubavski and others of the Soviet Union invented carbon dioxide gas shielded arc welding, which promoted the application and development of gas shielded arc welding, such as mixed gas shielded arc welding, flux-cored wire gas slag joint shielded arc welding and self-shielded arc welding.
1957 American Gage invented plasma arc welding; Electron beam welding invented by Germany and France in1940s was also applied and further developed in1950s. In 1960s, laser welding plasma, electron beam and laser welding methods reappeared, which marked the new development of high energy density fusion welding, greatly improved the weldability of materials, and enabled many materials and structures that were difficult to weld by other methods to be welded.
Other welding technologies include 1887. At that time, Thompson of the United States invented resistance welding and used it for spot welding and seam welding of thin plates. Seam welding is the earliest semi-mechanized welding method in pressure welding. With the progress of seam welding, the workpiece is pushed forward by two rollers. In the 1920s, flash butt welding was used to weld rods and chains. At this point, resistance welding has entered the practical stage. 1956, Jones of the United States invented ultrasonic welding; Chudkov of the Soviet Union invented friction welding; 1959, Stanford research institute in the United States successfully studied explosive welding; In the late 1950s, the Soviet Union manufactured vacuum diffusion welding equipment.