What are the welding techniques?

【Summary Description】 Welding technology What are the welding techniques? Hand arc welding is the earliest developed and most widely used welding method in various arc welding methods. It is coated with the outside of the electrode electrode and filler metal, the arc is burning between the end of the electrode and the surface of the welded workpiece. Under the action of arc heat, the coating can generate gas to protect the arc on the one hand, and on the other hand, it can generate slag to cover the surface of the molten pool to prevent the interaction between the molten metal and the surrounding gas. The more important role of slag is to produce physical and chemical reactions with molten metal or to add alloying elements to improve the properties of weld metal. Hand arc welding equipment is simple, light, flexible operation. It can be applied to the welding of short seams in maintenance and assembly, especially for welding of difficult to reach parts. Hand arc welding with the corresponding electrode can be applied to most industrial carbon steel, stainless steel, cast iron, copper, aluminum, nickel and its alloys. 2. Gas tungsten arc welding This is a non-melting gas shielded arc welding, which uses the arc between the tungsten electrode and the workpiece to melt the metal to form a weld. The tungsten pole does not melt during the welding process and only acts as an electrode. At the same time by the torch nozzle into argon or helium for protection. A metal may be additionally added as needed. Internationally known as TIG welding. Gas tungsten arc welding is an excellent method for joining sheet metal and backing due to its good control of heat input. This method can be used to join almost all metals, especially for welding aluminum, magnesium, which can form refractory oxides, and active metals such as titanium and zirconium. The weld quality of this welding method is high, but compared with other arc welding, the welding speed is slow. 3. MIG shielded arc welding This welding method is the use of continuous feeding of the welding wire and the workpiece burning between the arc as a heat source, by the torch nozzle of the gas protection arc to welding. The shielding gases commonly used in gas shielded arc welding are argon, helium, CO2 or a mixture of these gases. When argon or helium is used as shielding gas, it is called metal inert gas shielded arc welding (referred to as MIG welding in the world); When inert gas and oxidizing gas (O2,CO2) mixed gas is used as protective gas, or when CO2 gas or CO2 + O2 mixed gas is used as protective gas, or when CO2 gas or CO2 + O2 mixed gas is used as protective gas, it is collectively referred to as melting electrode active gas shielded arc welding (referred to as MAG welding in the world). The main advantage of MIG arc welding is that it can be easily welded in various positions, and it also has the advantages of faster welding speed and high deposition rate. Melt electrode active gas shielded arc welding can be applied to most major metals, including carbon steel, alloy steel. MIG welding is suitable for stainless steel, aluminum, magnesium, copper, titanium, zirconium and nickel alloys. Arc spot welding is also possible with this welding method. 4. Plasma arc welding Plasma arc welding is also a non-melting arc welding. It is the use of electrode and workpiece between the compression arc (called forward transfer arc) to achieve welding. The electrode used is usually a tungsten electrode. The plasma gas used to generate the plasma arc may be argon, nitrogen, helium, or a mixture of the two. At the same time, it is also protected by inert gas through the nozzle. Filler metal can be added during welding, or no filler metal can be added. Plasma arc welding welding, because of its straight arc, energy density, and thus the arc penetration ability. The keyhole effect produced during plasma arc welding can be carried out without beveling for most metals within a certain thickness range, and can ensure uniform penetration and weld. Therefore, plasma arc welding has high productivity and good weld quality. However, plasma arc welding equipment (including nozzles) is more complex, the control of welding process parameters is higher. Most of the metals that can be welded by gas tungsten arc welding can be plasma arc welding. In contrast, welding of extremely thin metals of 1mm or less can be easily performed by plasma arc welding. 5. Tubular welding wire arc welding Tubular welding wire arc welding is also the use of continuous feeding of the welding wire and the workpiece burning between the arc as a heat source for welding, can be considered as a type of MIG welding. The welding wire used is a tubular welding wire, the tube containing various components of the flux. During welding, a protective gas, mainly CO2, is applied. The flux is decomposed or melted by heat, which plays the role of slag forming to protect the solution pool, alloy infiltration and arc stabilization. Tubular welding wire arc welding in addition to the above-mentioned advantages of gas shielded arc welding, due to the role of the flux in the tube, so that it has more advantages in metallurgy. Tubular wire arc welding can be applied to the welding of various joints of most ferrous metals. Tubular wire arc welding has been widely used in some advanced industrial countries. The "tubular wire" is now referred to as "flux-cored wire".

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