laser weldingBrazinghigh-frequency welding

2)
    The laser welding is the use of high-power coherent monochromatic sub streams to the laser beam focus from the welding heat source. This welding method usually continuous power laser welding and pulsed power laser welding. The advantages of laser welding need not be carried out in vacuum, the disadvantage is the Penetration than electron beam welding. Laser welding energy can perform precise control, and thus can achieve precision microdevices welding. It can be applied to many metals, in particular, is able to solve a number of difficult to weld metal and the welding of dissimilar metals.
       4.
    Brazing energy may be a chemical heat of reaction, may be an indirect heat energy. It is the use of a melting point than the metal having a low melting point of the brazing material for brazing, brazing materials and rely on capillary action into the gap of the joint contact surface, wetting the surface of the welded metal is heated so that the solder melts, the liquid phase and interdiffusion between solid phase and form a brazed joint. Therefore, brazing is a solid phase and a liquid phase of welding methods. Brazing heating temperature is lower, the base material does not melt, but also do not need to apply pressure. But before welding must take certain measures to clear the the welders surface oil, dirt, oxide film. This is an important guarantee for the workpiece wettability, to ensure the quality of the joint. Solder liquidus line humidity is higher than 450 ° C but below the melting point of the base metal material, referred to as brazing; below 450 ℃, referred to as soldering. Different brazing can be divided according to the heat source or heating methods: flame brazing, induction brazing, furnace brazing, dip brazing, resistance brazing or the like. Brazing, when the heating temperature is relatively low, so the impact on the performance of the workpiece material, the stress distortion of the weldment is also smaller. However, the strength of the brazed joints generally low heat capacity. Brazing can be used for welding carbon steel, stainless steel, superalloy, metallic material such as aluminum, copper, can also be connected to a dissimilar metal, metal and nonmetal. Suitable for welding by not upload or room temperature connector is particularly suitable for precision miniature and complex multi-brazing seam weldment.
       5. Other welding methods
    These welding methods belonging to the different degrees of specialized welding method, a narrow its scope. Main the electroslag welding resistance heat energy, high-frequency welding; chemical energy for the welding gas welding, pressure welding, explosion welding; machinery for welding energy friction welding, cold welding, ultrasonic welding, diffusion welding.
Electroslag welding (1)
    As previously described, the slag resistance of the electroslag welding is a welding method of the heat energy. Welding process in the vertical welding position, the assembly gap formed by the the two workpiece face and both sides of the water-cooled copper slider. The welding current through the slag generated heat of the resistance of the workpiece ends melted. According to the shape of the electrode used in the welding, electroslag welding into silk electroslag welding, plate electroslag welding and melting mouth electroslag welding. The electroslag welding advantage of: welding workpiece thickness is greater than (from 30mm to 1000mm), and high productivity. Mainly used in the welding section butt joints and T-joints. The electroslag welding can be used for various steel welding, assembly welding can be used for casting. Electroslag welding head are slower due to heating and cooling, heat affected zone width, coarse microstructure and toughness, are generally required to normalizing after welding.
(2)
    The same frequency welding is solid resistance heat energy. Resistor thermal welding, using high-frequency current is generated in the workpiece so that the surface of the workpiece weld zone is heated to the melting or close to the plastic state, then applied (or not applied) upsetting force to achieve the binding of the metal. So it is a solid phase a resistance welding method. High frequency welding according to the high-frequency current to generate heat in the workpiece can be divided into contact with high-frequency welding and induction of high-frequency welding. Contacting the high-frequency welding, a high frequency current through the contact with the workpiece mechanical incoming workpiece. The induction of high-frequency welding, high frequency current through the workpiece the coupling effect of the external induction coil within the workpiece generates an induced current. High-frequency welding is a a strong specialized welding method, according to the product is equipped with special equipment. High productivity welding speed of up to 30m/min. Mainly used for the manufacture of pipes welded longitudinal seam or spiral seam.
(3) welding
    Welding with a gas flame of a welding method as a heat source. The most widely used in acetylene gas as fuel oxygen - acetylene flame. Easy to operate simple equipment but gas welding heating rate and low productivity, the heat affected zone and prone to large deformation. Gas welding can be used for welding of ferrous metals, non-ferrous metals and alloys. Generally applicable to repair and a single piece of sheet metal welding.
(4) pressure welding
    Pressure welding and gas welding, pressure welding gas flame as a heat source. Welding the two butt end portion of the workpiece is heated to a certain temperature, then applying sufficient pressure to obtain a firm joint. Is a solid phase welding. Pressure welding without filler metal, commonly used in the rails welded and welded steel.
(5) explosion welding
    Explosive welding is a chemical reaction heat energy of another solid phase welding method. But it is the use of the energy generated by the explosives to achieve a metal connection. Two metal within less than a second explosion waves can be accelerated impact the formation of the metal binding. The most widely in a variety of welding methods, the combined range of the explosive welding of dissimilar metals can be welded. Two metal welding metallurgy incompatible with explosion welding various transition joints. The explosion welding is used for the large surface area of ​​the tablet coated with an efficient method of manufacturing composite panels.
(6) friction welding
    Friction welding is the mechanical energy is the energy of the solid-phase welding. It is the use of the heat generated by mechanical friction between the two surfaces to achieve the connection of the metal. Friction welding heat is concentrated at the joining surfaces, and therefore the narrow heat-affected zone. Required to exert pressure between the two surfaces, and in most cases is increased when heat termination pressure, so that the hot metal by the upsetting is incorporated, generally combined with the surface is not melted. Friction welding productivity is high, almost all friction welding forging of the metal can in principle. Friction welding can also be used for the welding of dissimilar metals. To apply to the cross section is circular the maximum diameter of a workpiece of 100mm.
(7) The ultrasonic welding
    Ultrasonic welding is also a mechanical energy to the energy of the solid-phase welding method. For ultrasonic welding, the workpiece under the low static pressure, high frequency vibrations emitted by the acoustic pole enables joints generate strong crack friction and heated to the soldering temperature and form a combination. The ultrasonic welding can be used for the welding between the the most of the metal material, to achieve the welding between the metal, dissimilar metals and metal and nonmetal. Applied to the metal wire, or foil, or less than 2 ~ 3mm sheet metal joint repetitive.
(8) diffusion bonding
    Diffusion welding generally based on indirect heat energy solid-phase welding method. Is usually carried out in vacuum or under a protective atmosphere. Welding when the two welders member surface contact under high temperatures and large pressure and incubated for a certain time, to reach the distance between atoms, After atoms simplicity mutual diffusion bonded. Not only need to be cleaned before welding the workpiece surface oxides and other impurities, and surface roughness below a certain value in order to ensure the welding quality. Diffusion welding of welding material performance almost no harmful effects. It is a lot of the same species, and the dissimilar metal, as well as some non-metallic materials, such as ceramics, etc. can be soldered. Diffusion bonding can be the welding complex structure and thickness of very different workpiece.
       The welding process: → arc welding (TIG, manual arc welding, submerged arc welding, gas tungsten-shielded arc welding, and other high-energy beam welding (electron beam welding, plasma arc welding, gas metal arc welding) → resistance welding → laser welding) → brazing → the resistance heat energy: electroslag welding, high frequency welding; → chemical welding energy: gas welding, pressure welding, explosion welding; → machinery for welding energy: friction welding, cold welding ultrasonic welding, diffusion welding
Welding process accuracy deformation heat affected weld quality solder conditions of use
Laser welded precision small small good
 Brazing precision general general general needs of the overall heating
Generally no need electrode resistance welding precision greatly
TIG generally greatly generally need to need to electrode
Plasma welding is better in general general general need to need to electrode
Electron beam welding precision little good vacuum