Arc is the most widely used welding method. It includes: arc welding, submerged arc welding, gas tungsten arc welding, plasma arc welding, melting pole gas shielded arc welding and so on. Most of the arc is burning between the electrode and the workpiece the arc as heat source. In the formation of connections, it may or may not use filler metal. The electrodes used in the melting of the wire welding process when called MIG arc welding, such as arc welding, submerged arc welding, gas shielded arc welding, tubular wire arc welding, etc.; the electrodes used in the welding process does not melt the carbon rod or tungsten rods, called non-melting polar arc, such as TIG, plasma arc Aluminum Electrode and so on.
(1) arc welding
Arc welding is the development of a variety of arc welding method in the first, is still the most widely used as a welding method. It is coated with a coating of the external electrodes and filler metals for welding, arc welding is the welding tip and the surface between the combustion. Coatings under the action of heat in the arc gas can be generated on the one hand to protect the arc on the other hand can produce slag covering the weld pool surface, the molten metal to prevent the interaction with the surrounding gas. More important role in slag and molten metal is produced physical and chemical reactions or alloying elements added to improve the weld metal properties. Arc welding equipment is simple, lightweight, flexible operation. Can be applied to maintenance and assembly of the short seam welding, in particular, can be used for difficult to reach parts of the welding. Arc welding with a welding rod with the corresponding applicable to most industrial carbon steel, stainless steel, cast iron, copper, aluminum, nickel and their alloys.
(2) SAW
SAW is a continuous feed of wire as the electrode and when the filler metal. Welding, the welding area covered with a layer of granular flux, arc burning under the flux layer, the wire ends and the local base metal melting to form a weld. Under the action of heat in the arc, molten slag on the part of the flux and metallurgical reactions occur with the liquid metal. Slag floating on the surface of the metal pool, on the one hand to protect the weld metal, to prevent air pollution, and the molten metal produced with the physical and chemical reactions, and to improve the performance of the weld metal extreme; the other hand can also make the weld metal slow Coolers. Submerged arc welding can be used to a larger current. Compared with arc welding, its biggest advantage is that the weld quality, high welding speed. Therefore, it is particularly suitable for large parts of the straight seam welding of girth. And most of the mechanized welding. SAW has been widely used in carbon steel, low alloy steel and stainless steel welding. As the cooling rate of slag can reduce the joint, so some high-strength structural steel, high carbon steel, also can be used submerged arc welding.
(3) gas tungsten arc welding
This is a non-melting pole gas shielded arc welding is the use of tungsten arc between the workpiece and the metal melt and form a weld. Tungsten welding process does not melt, only play the role of the electrode. At the same time sent from the torch nozzle argon or helium for protection. Also needed to add another metal. Internationally known as TIG welding. Gas tungsten arc welding as well to control the heat input, so it is connected and backing weld sheet metal and a great way. This method can be used for virtually all metal connections, especially for welding aluminum and magnesium which can form refractory oxides such as titanium and zirconium metal, and these active metals. This welding seam of high quality, but compared with other arc welding, the welding speed is slower.
(4) plasma arc welding
Plasma arc melting is a non-polar arc. It is the use of compressed between the electrode and the workpiece the arc (called the forward transfer arc) to achieve welding. Is usually used in tungsten electrodes. Plasma arc generated plasma gas used argon, nitrogen, helium or mixture between the two of them. Also protected with an inert gas through the nozzle. Welding filler metal can be applied, you can not add filler metal. Plasma arc welding, arc due to its straight, energy density, which arc penetrating ability. Plasma arc welding holes generated effects, a certain thickness range for most metals can not open groove butt, and to ensure uniform penetration and weld. Therefore, plasma arc welding of high productivity, weld quality. However, plasma arc welding equipment (including nozzle) is more complex, control of welding parameters higher. Gas tungsten arc welding of most metals can be, can the use of plasma arc welding. In contrast, for less than 1mm thin metal welding, plasma arc welding can be easily used for.
(5) melting pole gas shielded arc welding
This welding method is to use a continuous feed of wire and electric arc burning between the workpiece as heat from the welding torch nozzle for gas arc welding. Melting pole gas shielded arc welding is usually used to protect gas are: argon, helium, CO2 gas or mixture of these gases. Argon or helium gas for the protection referred to as melting inert gas shielded arc welding (referred to as the international MIG welding); with inert gas and the oxidizing gas CO2, CO2) gas mixture for the protection, or CO2 gas or CO2 + O2 mixture for the protection of gas, or CO2 or CO2 + O2 gas mixture for the protection of gas, referred to as melting polar active gas arc welding (referred to as the international MAG welding). Melting pole gas shielded arc welding of the main advantages of the location can be easily welded, but also has a welding speed, deposition rate and so on. Melt very active gas arc welding applied to most of the major metals, including carbon steel, alloy steel. Melting inert gas welding for stainless steel, aluminum, magnesium, copper, titanium, zirconium and nickel alloys. Using this method can also be arc welding spot.
(6) tubular wire arc tubular wire arc welding is the use of continuous feeding of Welding Wire and workpiece the arc is burning between the heat source for welding, melting pole gas can be considered a type of welding. Tubular wire is used in wire, pipe that has the various components of the flux. Welding, plus a protective gas, mainly CO. Flux thermal decomposition or melting, slagging protection dissolved pool play, and the steady infiltration alloy arc and so on. In addition to tubular wire arc welding with the melting pole gas shielded arc welding of advantages, because the role of flux tubes, so more on the advantages in metallurgy. Tubular wire arc welding can be applied to most black metal of the welding joints. Tubular wire arc welding in a number of advanced industrial countries has been widely used.