Welding process is through heating, pressure, or both, with or without welding material, so that the two work pieces to produce mutual diffusion of atoms, the formation of metallurgical bonding process and connection. The welding application is very extensive, can be used both for metal and nonmetal. What are the technical features of the welding process?
1. Laser Welding: Laser radiation heating to the surface, surface heat through the heat conduction to the internal diffusion, through the control of laser pulse width, energy, peak power and repetition frequency and other laser parameters, so that the workpiece melting, forming a specific melting pool.
Laser welding technology is widely used in automobiles, ships, aircraft, high-speed railway and other high-precision manufacturing field, to people's quality of life has brought a significant upgrade, but also led the home appliance industry into the Seiko era.
2. Laser composite welding: laser beam welding and MIG welding technology combined to obtain the best welding effect, rapid and weld bypass capacity, is the most advanced welding methods. The advantages are: fast speed, small thermal deformation, small heat-affected area, and ensure the weld metal structure and mechanical properties.
Laser composite welding, in addition to the welding of automotive sheet structures, is also suitable for many other applications. For example, the application of this technology to the production of concrete pumps and mobile crane booms, these processes require the processing of high-strength steel, the traditional technology often because of the need for other ancillary processes (such as preheating) to lead to increased costs. Moreover, the technology can also be used in the manufacture of rail vehicles and conventional steel structures (such as bridges, fuel tanks, etc.).
3. Friction Stir welding: Using friction heat and plastic deformation heat as welding heat source. Friction stir welding process is a cylinder or other shape (such as threaded cylinder) of the mixing needle into the workpiece joints, through the high-speed rotation of the welding head, so that it and welding workpiece material friction, so that the junction of the material temperature increase softening.
Friction stir welding can be achieved between dissimilar materials, such as metal, ceramics, plastics and so on. Friction Stir welding welding high quality, not easy to produce defects, easy to achieve mechanization, automation, quality stability, low cost and high efficiency.
4. Electron beam welding: Electron beam welding is a method of welding by using accelerated and focused electron beam bombardment to heat energy produced by welding parts in vacuum or non vacuum.
Electron beam welding is widely used in aerospace, atomic energy, national defense and military industry, automobile and electric electrician instrument, because it has the advantages of no electrode, easy oxidation, good repeatability of process and small heat deformation.
5. Flash Butt Welding: The use of the welding machine to make both ends of the metal contact, through the low voltage of the strong current, until the metal is heated to a certain temperature softened, the axial pressure of the top forging, forming a pair of welding head.
6. Ultrasonic Metal Welding: A special method of connecting the same metal or dissimilar metals using the mechanical vibration energy of ultrasonic frequencies. Metal in the ultrasonic welding, neither to the workpiece to convey the current, nor to the workpiece to the high-temperature heat source, but under static pressure, the box vibration energy into the work of the workplace friction, deformation energy and limited temperature rise. The metallurgical bonding between joints is a kind of solid state welding which is realized under the condition that the parent material does not melt.
Ultrasonic metal welding has the advantages of fast, energy-saving, high fusion strength, good conductivity, no spark, close to cold processing; The disadvantage is that the welding metal parts can not be too thick (generally less than or equal to 5mm), solder points can not be too large, need to be pressurized.