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What Are The Common Welding Processes Describe What Has
- Oct 24, 2014 -

Before welding processes commonly used are: 

→ arc welding (TIG, arc welding, submerged arc welding, gas tungsten arc welding, plasma arc welding, gas welding) 

→ ERW 

→ high-energy beam welding (electron beam welding, laser welding) 

→ brazing 

→ with resistance heat energy slag bath surface covered to prevent molten metal interaction with the surrounding gas. More important is the role of slag and molten metal to produce physical and chemical reactions or add alloying elements to improve the weld metal properties. Manual arc welding equipment is simple, lightweight, and flexible operation. Maintenance and assembly can be applied to the short welding seams, in particular can be difficult to reach parts for welding. MMA is equipped with the appropriate applicable to most industrial welding of carbon steel, stainless steel, cast iron, copper, aluminum, nickel and its alloys. 

(2) SAW 

Submerged arc welding is when a continuous feed, as electrodes and filler metal. When welding, the welding area is covered in a layer above the granular flux in the arc burning solder layer, and the wire end and base material partially melted to form a weld. Under the action of the arc heat, melt the solder on the part of the slag and metallurgical reactions occur with the liquid metal. Slag floating on the surface of the metal bath, one can protect the weld metal, to prevent air pollution, and with the molten metal to produce physical and chemical reactions, and properties of the weld metal to improve the extreme; the other hand, can also make the weld metal ling was slow. Submerged arc welding can be employed a larger current. Compared with manual arc welding, its biggest advantage is a good weld quality, high welding speed. Therefore, it is particularly suitable for large parts of the straight seam welded girth. And most mechanized welding. Submerged arc welding is widely used in carbon steel, low alloy steel and stainless steel. Since the slag cooling rate can be reduced joints, so some high-strength structural steel, high carbon steel, also can be submerged arc welding. 

(3) gas tungsten arc welding 

This is a non-MIG arc welding, is the use of electric arc between tungsten electrode and the workpiece to form a molten metal weld. TIG welding process is not melted and only function as an electrode. While feeding argon or helium for protection from the torch nozzle. Also based on the need to add additional metal. Internationally known as tig welding. Gas tungsten arc welding can be well controlled due to the heat input, so it is an excellent method of sheet metal and backing weld connections. This is a non-MIG arc welding. It is the use of compressed between the electrode and the workpiece arc (call forwarding transferred arc) to achieve welding. The electrode is generally used tungsten. Another solid-phase welding method is to weld fried chemical reaction heat for energy. But it is the use of energy generated by explosives to achieve metal connections. In the blast wave effect, two pieces of metal in less than a second of time can be accelerated to form a combined impact of metal. In a variety of welding methods, the most explosive welding can weld a wide range of combinations of dissimilar metals. Explosion welding will be used on the two metal welding metallurgy become incompatible various transition joints. Explosive welding relatively large surface area for multi-coated tablet, is a highly efficient method of manufacturing a composite plate. 

(6) friction welding 

Friction welding is the mechanical energy is the energy of the solid-phase welding. It is the use of mechanical friction between two surfaces heat generated to achieve metal connections. Friction welding heat concentrated in the joints, and are therefore narrow heat-affected zone. Applying pressure between the two surfaces to be, in most cases is to increase the pressure at the termination of heating, the thermal state of the metal are bonded by forging, general structure of a plasma arc generated plasma gas can be used argon, nitrogen, helium, or a mixture of both of which gas. But also through a nozzle with an inert gas protection. Plus filler metal can also be without filler metal during welding. When the plasma arc welding, etc., because of its arc straight, energy density, and thus strong arc penetration. Keyhole effect produced when plasma arc welding, for most metals within a certain range of thickness can not open butt, and to ensure uniform penetration and weld. Thus, plasma arc welding of high productivity, good weld quality. However, plasma arc welding equipment (including nozzle) is more complex, the control of welding parameters require higher. Gas tungsten arc welding can weld most metals, can be used plasma arc welding. In contrast, less than 1mm for the welding of very thin metal, with a plasma arc can be performed more easily. (5) MIG arc welding 

This welding method using a continuous feeding of combustion between the workpiece and the arc welding wire as a heat source, the welding torch nozzle for gas shielded arc welding. MIG arc welding shielding gas commonly used are: argon, helium, co2 gas or gas mixture of these gases. China International Mould Network when argon or helium as a shielding gas known as metal inert gas shielded arc welding (mig internationally referred to as welding); inert gas and oxidizing gas (o2, co2) welding 

Tubular wire arc welding is continuously fed by the combustion between the wire and the workpiece as the heat source for electric arc welding, can be considered a type of MIG welding. The wire is a tubular wire used, the tube that has the flux of the various components. When welding, the shielding gas is applied mainly co. Thermal decomposition or melting flux plays slagging protect the bath, alloying and arc stability and so on. In addition to the tubular wire arc welding electrode having the advantage of gas-shielded arc welding of the said melting, the flux due to the inner tube, to make it more advantageous in metallurgy. Tubular wire arc welding can be applied to most ferrous metal various joints. Tubular wire arc welding in some advanced industrial countries have been widely used. 

2 ERW 

This is the energy of a thermal resistance welding methods class, including slag resistance of the heat energy of the solid resistance electroslag welding and resistance welding heat energy. Since ESW more unique characteristics, so on the back introduction. This introduces some solid resistance heat resistance welding for energy, mainly spot welding, seam welding, projection welding and butt welding and so on. Resistance welding is generally the workpiece under pressure in a certain electrode and the workpiece in this category two by the current through the resistor heat welding method generated artifacts will include: electron beam welding and laser welding. 

(A) electron beam welding 

Electron beam welding is the thermal energy of the high-speed electron beam focused on the surface of the workpiece generated by welding. Electron beam welding, an electron beam generated by the electron gun and accelerating. Commonly used in electron beam welding: high vacuum electron beam welding, low vacuum electron beam welding and the non-vacuum electron beam welding. The first two methods are carried out in a vacuum chamber. Weld preparation time (mainly vacuum time) longer, workpiece size by the vacuum chamber size limit. Compared with electron beam welding arc, the main feature is the deep penetration welds, weld width, high weld metal purity. It can be used in precision welding thin materials, but also can be used in very thick (most thick 300mm) slag resistance welding is a welding method for thermal energy. Welding process is vertical welding position, in a two-piece assembly gap end and both sides were formed by water-cooled copper block. Using the current through the welding slag resistance heat generated by melting an end portion of the workpiece. According to the shape of the welding electrode used, electroslag welding wire into electroslag welding, electroslag welding and melting plate mouth electroslag welding. Electroslag welding advantages are: large workpiece thickness weldable (from 30mm to more than 1000mm), and high productivity. Mainly used for welding in section T-joints and butt joints. Electroslag welding can be used for a variety of steel welding can also be used for welding castings. Electroslag welding head are slow due to heating and cooling, heat affected zone width, microstructure thick, toughness, and therefore must be normalized after the welding process in general. 

(2) high-frequency welding 

Same frequency welding is a solid resistance heat energy. Thermal resistance welding using high-frequency current generated within the workpiece so that the workpiece is heated to melt the surface of the weld zone or close to a plastic state, then applied (components soldered all other welding methods can be used for fusion welding of metals and alloys can be used electron beam welding, mainly for applications requiring high-quality welding products.'ll solve dissimilar metal, easily oxidized metal and refractory metal welding, but is not suitable for high-volume products. 

(2) Laser Welding 

Laser welding is the use of high-power coherent monochromatic light from the sub-flow soldering focused laser beam as the heat source. This welding method is usually a continuous power laser welding and pulsed-power laser welding. The advantage is that no laser welding in vacuum, the disadvantage is not as electron beam welding penetration and strong. When laser welding can be precisely controlled energy, and thus can achieve precision micro welding device. It can be used in many metals, particularly difficult to solve some of the weld metals and welding of dissimilar metals. 

4 brazing 

The braze may be a chemical reaction heat energy, or may be an indirect heat. It is the use of a lower melting point than the melting point of the metal brazing material for welding the material, heated to melt the solder, the solder and by capillary action into the gap between the contact surface of the joint, wetting the metal surface to be welded, and the liquid phase and brazed joints between the formation of the solid phase interdiffusion. Thus, brazing is a solid phase and liquid phase soldering method. Low brazing temperature, the base metal is not melted, but also without applying pressure. Methods 

These welding methods belong to different degrees of specialized welding method, its application range is narrow. Mainly include resistance heat energy electroslag welding, high frequency welding; chemical energy can be welded welding, pressure welding, explosion welding; welding energy to mechanical energy to friction welding, cold welding, ultrasonic welding, diffusion welding. 

(1) electroslag welding 

As mentioned earlier, slag or not applied) upsetting force to realize the combination of the metal. So it is a solid-phase resistance welding methods. Depending on how high-frequency welding of high-frequency current to generate heat in the workpiece can be divided into contact with a high-frequency induction welding and high frequency welding. Contact frequency welding, high frequency current through contact with the workpiece mechanical and incoming artifacts. High frequency induction welding, the high-frequency current through the coupling of the workpiece external induction coil to generate induced currents in the workpiece. High frequency welding is a highly specialized welding method, according to the product is equipped with special equipment. High productivity welding speeds of up to 30m / min. Mainly used for longitudinal seam or spiral seam welded pipe manufacturing. 

(3) Gas welding 

Gas welding is a welding method using a gas flame as a heat source. The most widely used is oxygen acetylene gas as fuel - acetylene flame. Since the device is simple to make easy operation, but does not burst occlusal surface melting. Higher friction welding productivity, almost all can in principle be able to forging metal friction welding. Friction welding can also be used for welding dissimilar metals. To apply to the circular cross-section of 100mm the maximum diameter of the workpiece. 

(7) Ultrasonic welding 8) diffusion bonding generally based on indirect heat diffusion welding solid-phase welding method for energy. Is usually carried out in a vacuum or protective atmosphere. Welding so that the two surfaces are in contact welders and incubated for a certain time at high temperature and large pressure to achieve the interatomic distance, through the combination of atomic interdiffusion simple. Not only need to be cleaned before welding surface oxides and other impurities, and the surface roughness of less than a certain value in order to ensure the welding quality. Diffusion welding harmful effects on the performance of the welded materials were almost no. It can be welded to the same lot as well as some types of dissimilar metals, and non-metallic materials, such as ceramics. Diffusion welding can weld complex structure and the thickness of the workpiece vary greatly.