Welding, also known as welding, is a manufacturing process and technique for joining metals or other thermoplastic materials such as plastics by heat, high temperature, or high pressure.
There are many energy sources for modern welding, including gas flame, arc, laser, electron beam, friction and ultrasonic. In addition to being used in factories, welding can be performed in a variety of environments, such as in the field, underwater, and in space. Welding can be dangerous to the operator wherever it is, so proper precautions must be taken when welding. The possible injuries caused by welding to the human body include burns, electric shock, visual impairment, inhalation of toxic gases, and excessive ultraviolet radiation.
Welding achieves the purpose of joining in the following three ways:
1. Fusion welding - heating the workpieces to be joined to locally melt them to form a molten pool. After the molten pool cools and solidifies, it is joined. If necessary, fillers can be added to assist. It is suitable for welding of various metals and alloys. pressure.
2. Pressure welding - the welding process must apply pressure to the weldment, which belongs to the processing of various metal materials and some metal materials.
3. Brazing - use a metal material with a lower melting point than the base metal as the brazing filler metal, use the liquid brazing filler metal to wet the base metal, fill the joint gap, and diffuse with the base metal to connect the weldment. It is suitable for welding of various materials, and also suitable for welding of different metals or dissimilar materials.
During the welding process, the workpiece and the solder melt to form a molten region, and the connection between the materials is formed after the molten pool cools and solidifies. During this process, pressure is usually also applied. There are many energy sources for welding, including gas flame, arc, laser, electron beam, friction and ultrasonic. Before the end of the 19th century, the only welding process was metal forging, which blacksmiths have used for hundreds of years. The earliest modern welding techniques appeared at the end of the 19th century, first arc welding and oxy-fuel welding, and later resistance welding. In the early 20th century, with the war between the first and second world wars, there was a great demand for cheap and reliable connection methods for military equipment, so the development of welding technology was promoted. Today, with the widespread use of welding robots in industrial applications, researchers are still delving into the nature of welding and continue to develop new welding methods to further improve welding quality.
