Knowledge of welding techniques are introduced: Welding technology since the invention so far there are over a hundred years of history, all important products in the industrial production, such as aviation, aerospace and nuclear industries in manufacturing are Welding Materialtechnology. At present, the development of new industries forcing welding technology continues to advance and promote the development of micro-connection technology and equipment, such as the development of the microelectronics industry; promote the development of ceramic materials and composites vacuum brazing, vacuum diffusion welding, spraying and bonding process development. Welding technology With the advancement of science and technology development, mainly in the following aspects: 1, the energy aspects: Currently, the welding heat source has a very rich, such as flame, arc, resistive, ultrasonic, friction, and other ions, electron beam, laser beam, microwave, etc., but the research and development of the welding heat source is not terminated, its new development can be summarized in three aspects: the first is the improvement of the existing heat source, to make it more effective, convenient, affordable, In this regard, the development of the electron beam and the laser beam welding of more significant; Secondly is to develop better, more efficient heat source , using two kinds of the heat source is superimposed in order to obtain a greater energy density, for example, laser beam, etc. is added in the electron beam welding; third energy-saving technologies. Due to the the welding energy consumption, so there are a lot of new technologies to achieve energy saving, such as solar welding, resistance spot welder power factor in the development of electronic technology to improve. 2, the computer in the welding application: Arc welding equipment microcomputer control system, analysis and control of a number of parameters such as Welding Wire Chinacurrent, welding speed, arc length, display and data retention welding operation procedures and parameters change, so as to give exact information about the quality of welding. Established as the core of computer control system including the welding sequence control system, PID control systems, optimal control and adaptive control system. These systems have been applied in the electric arc welding, pressure welding and brazing welding method. Computer software technology in the welding used more and more to get people's attention. At present, the computer simulation technology has been used in the welding thermal process, the simulation of welding metallurgy process, welding stress and deformation; database technology is used to create the the welders file management database, the searchable database of welding symbols, welding procedure qualification database searchable database of welding materials ; in the field of welding, CAD / CAM application is in continuous development phase, welding flexible manufacturing system has emerged. 3, welding robots and intelligent: Welding robot welding automation revolutionary progress, it broke through the traditional way of rigid welding automation, and open up a new way of flexible automation, welding robot main advantages: stability and improve the quality of welding, welding products to ensure the uniformity; improve productivity a day to 24 hours of continuous production; may be harmful to the environment, long-term work to improve the working conditions of workers; reduce workers to operate the technical requirements; small batch production welding automation can be realized; provide the technical foundation for flexible welding production lines. In order to increase the degree of automation of the welding process, in addition to control of the automatic tracking of the arc weld, and should also be real-time control the quality of welding, the welding groove conditions for this need to be detected in the welding process, such as the bead width, penetration and the weld bead on the back forming, etc., in order to be able to promptly adjust the welding parameters to ensure the good quality of the welding, which is intelligent welding. The intelligent welding the first focus of development in the visual system, its key technologies of sensor technology. Although intelligent is still in the initial stage, but there are broad prospects, is an important direction of development. On welding engineering expert system, at home and abroad in recent years have been more in-depth research, and has launched or prepared to launch of some commercialization welding experts system. Welding expert system is the level of the equivalent expert knowledge and experience, as well as computer software system has the ability of specialized welding problems. Integrated computer management system developed based on the quality of welding in welding applications, and its contents, including the initial test data and data analysis, product quality inspection, sales supervision, its software, including database, experts systems and other technology. 4, to improve the welding productivity (welding technology): Improve welding productivity is an important driving force to promote the development of welding technology. Improve productivity through two aspects: One is to improve the weld deposition rate. Hand arc welding iron powder, gravity welding, lying welding process; in multi-wire submerged arc welding, hot wire welding are such that the effect is significant. For example, three-wire submerged arc welding process parameters for 2200A 33V; 1400A X 40V 1100A X45V small cross-section of the groove, the back of the baffle or liner, 50 - 6mm steel plate a penetration forming, welding speed more 0.4m/min its deposition efficiency is 100 times more than the manual arc welding. Second, to reduce the groove cross-section and the amount of deposited metal, the most outstanding achievements in the past 10 years is a narrow gap welding. Narrow gap welding using the gas metal arc welding based, single wire, two-wire or three-wire welding. The joint thickness docking can be used in the form. For example, the plate thickness from 50 - 300mm, the gap can be designed around 13mm, and thus the amount of metal into the desired fused multiple, several times be reduced, thus greatly improving the productivity. The narrow gap welding technology the key is how to ensure that both sides of the penetration and arc center automatically tracking in the groove center line. In order to solve these two problems, the countries in the world to develop a variety of different programs, so we had a wide variety of narrow gap welding method. Electron beam welding, laser beam welding, plasma arc welding, can be butt joints, and do not open the wave port, so is ideal for narrow gap welding method, this is one of the important reasons of their widespread attention.
Kawamura et al as early as in 1995 and 1997 Zr65AloNi. oCu amorphous Brazing Alloy powder is heated to slightly above the glass transition temperature, the alloy powder in the supercooled liquid region to 1.0GPa put pressure on. Since the alloy has too wide supercooled liquid region and a lower subcooled liquid viscosity the powder compression the porosity is only 1, the tensile strength and elastic modulus were reached 1520MPa and 80GPa, close to the amorphous block of the liquid quenching and the values ??of the amorphous ribbon.
2 explosion welding
Explosion welding is explosives as an energy source for welding metals, using the impact force generated by the explosion, the weldment violent collision occurs, mutual diffusion between the plastic deformation, melting and atoms, in order to achieve a method of the connection weldment, characterized by allows any The same material, in particular the different kinds of materials instantaneously and firmly welded together.
3 flash welding
Between two amorphous alloy Zr5A1iCu ∞ welding test, process parameters Voltage 100 ~ 180V, the successful implementation of the amorphous alloy welding flash welding. After testing. Remains amorphous structure of the specimen at the weld interface without defects, welds and heat affected zone, no crystallization occurs, and post-weld specimens tensile strength of 1540MPa, almost equal to the pre-welding of amorphous alloy.
4 laser welding
Laser welding using a high energy density laser beam is irradiated on the specimen surface. Material absorption of part of the light can be converted into thermal energy, to melt the material, to achieve a high-precision welding method for welding, in the output power of 1.2kW, spot 0.3mm, welding speed, respectively 2,4,8 m / min Process conditions under, the homogeneity amorphousBrazing AlloysZr45Cu48Al of welding. After testing, welding speed 8m/min, weld and heat affected zone no holes, no cracks, no crystallization of the organization to maintain the amorphous structure. Successful implementation of the amorphous alloy welding.
5 electron beam welding
Electron beam welding is a welding method for a high energy density, the use of the acceleration, focus, and spatial orientation of the high-speed movement of the electron beam strikes the surface of the workpiece after a portion of the kinetic energy is converted to heat, so that the weld metal is molten, and cooled and solidified to form the weld a welding process.
6 Friction Welding
Friction welding is the the workpiece Q relative movement generates frictional heat to make the joint surface was heated to forging temperature, under the action of the pre-forging force, is formed by the plastic deformation of the material and diffusion process, solid connection welding method.
7 Friction Stir Welding
The principle of friction stir welding seams of the artificial member is a cylindrical shape of the welding head extension, high speed rotation of the welding head, with the friction of the workpiece material, the material temperature rises softening, while the material was stirred to complete the welding method. Patented welding technology is put forward in 1991 by the British Institute of Welding friction stir welding, friction stir welding temperature is relatively low, a small structure of after welding residual stress and distortion than welding, it caused the emergence of the welding industry attention, also gradually for amorphous alloy welding.