Welding plays an important role in mechanical production. For those who have a preliminary understanding of welding, it is necessary to understand several welding methods, which will be very helpful for the application of welding in production. Here is a brief introduction to several common methods of welding.
Welding rod electric arc welding is a process method that uses the stable burning arc established between the welding rod and the workpiece to melt the welding rod and the workpiece, so as to obtain a firm welding joint. During welding, the coating is continuously decomposed and melted to generate gas and slag, which protects the electrode end, arc, molten pool and its surrounding areas, and prevents harmful pollution of the atmosphere to the molten metal. The electrode core also melts continuously under the action of arc heat and enters the molten pool to form the filler metal of the weld.
Submerged arc welding (including submerged arc surfacing and electroslag surfacing) is a welding method in which the arc burns under the flux layer. Its inherent advantages, such as stable welding quality, high welding productivity, no arc light and little smoke and dust, make it the main welding method in the fabrication of important steel structures, such as pressure vessels, pipe section manufacturing, box girders and columns.
Argon arc welding is a welding technology using argon as the shielding gas. It is also called argon gas shielded welding. Argon shielding gas is applied around the arc welding area to isolate the air from the welding area and prevent oxidation of the welding area.
Argon arc welding technology is a welding technology based on the principle of ordinary electric arc welding, which uses argon to protect the metal welding materials, and uses high current to melt the welding materials on the substrate to form a molten pool, so that the metal to be welded and the welding materials can achieve metallurgical combination. As argon is continuously sent in high temperature fusion welding, the welding materials cannot contact with oxygen in the air, thus preventing the oxidation of the welding materials, so that stainless steel Iron hardware.
Gas welding, in English: oxygen fuel gas welding (OFW for short). It is a welding method that uses the flame generated by the mixed combustion of combustible gas and combustion supporting gas as the heat source to melt the weldment and welding materials to achieve the combination between atoms. The combustion supporting gas is mainly oxygen, and the combustible gas is mainly acetylene, liquefied petroleum gas, etc.
Laser welding is a method of welding by using focused laser beam as energy to bombard the heat generated by the weldment. Because of the optical properties of laser, such as refraction and focusing, laser welding is very suitable for welding micro parts and parts with poor accessibility. Laser welding also has the characteristics of low heat input, small welding deformation and immunity from electromagnetic field.
Laser welding has not been widely used because of the high price of laser and low electro-optic conversion efficiency.
The second shielded welding (full name: carbon dioxide gas shielded welding) process is applicable to the welding of various large steel structures of low carbon steel and low alloy high-strength steel. It has high welding productivity, good crack resistance, small welding deformation, and a large range of deformation. It can be used to weld thin and medium thick plates.
Friction welding is a welding method that uses the heat generated by the friction of the workpiece contact surface as the heat source to make the workpiece plastic deformation under pressure.
Under the action of pressure, it is under the action of constant or increasing pressure and torque that the relative motion between the welding contact end faces generates friction heat and plastic deformation heat on the friction surface and its surrounding areas, so that the temperature in and around the friction surface rises to a temperature range close to but generally lower than the melting point, the deformation resistance of the material decreases, the plasticity increases, and the oxide film at the interface breaks. Under the action of upset forging pressure, With the plastic deformation and flow of materials, solid state welding is realized through the molecular diffusion and recrystallization of the interface.