History of welding process

Welding technology has emerged with the smelting production of metals such as copper and iron and the application of various heat sources. The ancient welding methods were mainly cast, brazed, forged and riveted. The iron-bladed copper gongs manufactured by the Shang Dynasty in China are the welded parts of iron and copper. The fusion line of copper and iron on the surface is meandering and well-joined.

During the Spring and Autumn Period and the Warring States period, there were many dragons on the bronze drums in the tomb of Zeng Houyi, which were formed by segmental brazing. After analysis, the composition used is similar to that of modern solder. The swords made during the Warring States Period were made of steel with a blade and wrought iron on the back. They were generally heated and forged. According to the book "Tiangong Kaiwu" written by Song Yingxing of the Ming Dynasty, in ancient China, copper and iron were heated together, and forged and knives and axes were made by forging. The yellow mud or sieved Chen Jiuqiang soil was sprinkled on the interface. Segmented brazing large anchors. In the Middle Ages, weapons were also produced by forging welding in Damascus, Syria.

Ancient welding technology has long stayed at the level of casting, forging, brazing and rivet welding. The heat source used is fire, low temperature, inconsistent energy, and can not be used for welding large-section, long-weld workpieces. Can be used to make decorations, simple tools, living utensils and weapons. At the beginning of the 19th century, Davis of the United Kingdom discovered two high-temperature heat sources that could locally melt metals, such as arc and oxyacetylene flames. In 1885–1887, Benaldos of Russia invented carbon-polar arc welding tongs; in 1900, aluminum appeared again. Heat welding.

At the beginning of the 20th century, carbon arc welding and gas welding were applied. At the same time, thin arc welding electrode arc welding occurred. The arc was relatively stable, the welding pool was protected by slag, the welding quality was improved, and the manual arc welding entered the practical stage. Welding has been an important welding method since the 1920s. It has also become the beginning of the development of modern welding processes. During this period, Noble of the United States used the arc voltage to control the welding rod to feed the speed to make an automatic arc welder, which became the beginning of welding mechanization and automation. In 1930, Robinov of the United States invented submerged arc welding using welding wire and flux, and the mechanization of welding was further developed. In the 1940s, tungsten and molten inert gas shielded welding were introduced to meet the needs of welding aluminum, magnesium alloys and alloy steels.

In 1951, the Barton Institute of Electric Welding in the Soviet Union created electroslag welding, which became an efficient welding method for large-thickness workpieces. In 1953, the Soviet Union's Liubovsky and others invented carbon dioxide gas shielded welding, which promoted the application and development of gas shielded arc welding, such as the emergence of mixed gas shielded welding, flux-cored wire and slag joint protective welding and self-protective arc welding. Wait. In 1957, Gage in the United States invented plasma arc welding; in the 1940s, electron beam welding invented in Germany and France was also practical and further developed in the 1950s; in the 1960s, the emergence of laser welding plasma, electron beam and laser welding methods appeared. The new development of high energy density welding has greatly improved the weldability of materials and has enabled many materials and structures that are difficult to weld by other methods.

Other welding techniques are also available in 1887. Thompson in the United States invented resistance welding and used for spot welding and seam welding of thin plates. Seam welding is the earliest semi-mechanized welding method in pressure welding. With the seam welding process, the workpiece is two The rollers were pushed forward; in the 1920s, the use of flash butt welding to weld bars and chains began. At this point, resistance welding has entered a practical stage. In 1956, Jones of the United States invented ultrasonic welding; Chutkov of the Soviet Union invented friction welding; in 1959, the Stanford Institute of the United States successfully studied explosive welding; in the late 1950s, the Soviet Union made vacuum diffusion welding equipment.

The emergence of welding caters to the need for new technological means in the development of metal art. On the other hand, the unique and wonderful changes produced by the metal under the influence of welding heat also satisfy the metal art's demand for a new artistic expression language. In today's metal art creations, welding can and is being expressed as a unique artistic expression language. This paper analyzes the emergence and application of this technology.

Artistic creation and craftsmanship are always inseparable. As an industrial technology, the emergence of welding caters to the needs of the development of metal art for new processes. On the other hand, the unique and wonderful changes produced by the metal under the influence of welding heat also satisfy the metal art's demand for a new artistic expression language. In today's metal art creations, welding can and is being expressed as a unique artistic expression language. The art of metal welding can be separated from traditional metal art as a relatively independent art form in a branched way, because welding is artistic.

Welding can produce a rich expression language of artistic creation. Welding is usually done at high temperatures, and metals produce many wonderful changes at high temperatures. The metal base material will undergo color change and thermal deformation (ie, weld heat affected zone); the wire will form some beautiful texture after melting; and welding defects are often used in the art of welding. Welding defects refer to defects in the welded joint that do not meet the design or process requirements during the welding process. Its manifestations mainly include welding cracks, pores, undercuts, incomplete penetration, unfusion, slag inclusion, welding, collapse, pits, burn through, inclusions, etc. This is a very interesting phenomenon: the artistic nature of welding is usually reflected in the failure of some industrial welding operations, or in some welding defects that industrial welding is extremely difficult to avoid. Second, the welding art language is unique. Using different metal materials and using different welding techniques, the art of welding can be fully realized in different metal art forms.

In welding sculptures, welds and cuts are not passively present as a trace of technical processing, but are expressed in a wonderful and indispensable expression language. A welding sculpture, the thick weld is exposed on the surface of the sculpture, and various irregular cutting marks have become the artist's beautiful artistic language. In many cases, due to the rough and rustic style pursued by the welding sculpture, the metal is rusted, Most of them are reserved according to the needs of the work. Therefore, a non-carved, original beauty can often be felt in the welding sculpture.

The weld seam of the steel plate joint in the lower part of the sculpture is very large. From the point of view of the firmness of the welding process, it is obviously not only for the consideration of the degree of solidity of the sculpture. In this sculpture, the lower twisted welds have been used as An important factor in the overall aesthetic of sculpture is an indispensable part of it. From the overall perspective of the sculpture, whether it is the upper part of the text, or the lower part of the texture treatment, there are twisted weld marks everywhere, the whole work has reached the unity of the overall visual language. The manual plasma cutting method uses the heat of the current during cutting to create a heat-affected zone on the cutting edge, thus "staining" the bright white stainless steel with a slightly gradual color. At the same time, through the adjustment of the welding specification, the strong airflow from the torch will “blow” a randomly formed texture at the cutting edge at the moment the cutting steel plate melts, and solidify into a beautiful cut after the metal is cooled by the cutting. Traces, in contrast to the flat, bright stainless steel sheet in the middle. The formation process of this random effect has certain contingency, but it is a phenomenon that must be produced under certain welding specifications. From the perspective of size, the larger size of the welded art wall decoration can be semi-automatic CO2 gas shielded welding, and the smaller one can be manually tungsten argon arc welding.

If a wall painting is regarded as a painting, the processing of dots, lines, faces, black, white, gray and even colors in the picture can be achieved by welding. Various types of wire, various materials, different welding processes will appear in different forms on the screen. The color of different metals is different, the bright silver of stainless steel, the sub-silver of aluminum, the black color of carbon steel, titanium steel, bronze, copper, brass and steel. Different steels will have different colors when heated at high temperature. The change, that is, the heat affected zone of the weld is different. In addition, cutting is also one of the methods of welding art wall decoration. It can be used in combination with welding or alone, depending on the creative intention of the creator and the mastery of the craft and effect. The methods described above are combined and the richness of the changes can be imagined.

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