In our high-tech age, refractory, heat-resistant, anticorrosive, and radiation-resistant materials are becoming more widespread, for the welding of which special techniques are required. Such as electron beam welding, in which the temperature of the active working zone reaches a thousand times greater indicator than with traditional methods. Ultrahigh temperatures in this type of welding are achieved thanks to photons or electrons moving in a vacuum chamber at a speed of about 165,000 km / s. When a metal is bombarded at such an incredible speed, the kinetic energy of elementary particles is converted into heat, which melts the metal.
Electron beam welding is carried out in a special chamber from which air is previously pumped out. Airless space is created so that the electrons do not spend their energy on the ionization of the gas mixture and to obtain ideal metal joints without extraneous inclusions. The electron-beam installation, as this vacuum chamber is called, is equipped with a special magnetic lens designed to form a directed electron flow and effectively control it. Also, for the supply of welded parts, there is a loading hatch in it.
Electron beam welding is performed by alternating current of low voltage. It flows through a special focusing element (lens), where the cathode with the anode is located, and, thus, an electronic stream with specified characteristics is created. In low-power installations, a tungsten or tantalum spiral is used as a cathode. And if the technological process and the individual properties of the materials being welded require more power, then cathodes made of cermet or lanthanum hexaboride, which have an increased ability to emit free electrons, are already used.
Depending on the design features of the installation, electron beam welding can be performed by moving the material being welded perpendicular to a fixed beam or vice versa the beam can move relative to a fixed part. Also, the design of some installations provides for the presence of special deflecting devices, which gives more opportunities for curly seams.
This type of welding is widely used for welding high-strength alloy steels and alloys based on titanium, as well as metals such as molybdenum, tantalum, niobium, tungsten, zirconium, beryllium. For precise machining and welding of various micro-parts. It is used in industries such as rocket science, nuclear power, precision instrumentation, microelectronics and many others.
Along with electron beam technology, laser welding is also widespread . The equipment for this type of welding is an optical laser generator, which is an ultramodern source of coherent radiation. The fundamental difference between laser welding and the electron beam method is that it does not require vacuum chambers. The welding process using laser technology is carried out in air or in conditions of saturation of the chamber with special protective gases - carbon dioxide, argon and helium.