Electron beam welding is welding, the source of energy in which is the kinetic energy of electrons in an electron beam formed by an electron gun.
It is used for welding refractory, highly active metals in the space, aviation industry, instrument making, etc. Electron beam welding is also used to obtain high-quality welds with deep penetration of metal, if necessary, for large metal structures.
Content
History
The first installation for electron beam welding was created at MPEI in 1958. Currently, ELU-27, ELSTU-60, MEBW-60, and others are produced.
Entity
Electron beam welding is carried out by an electron beam in vacuum chambers. The dimensions of the chambers depend on the dimensions of the parts to be welded and range from 0.1 to several hundred cubic meters.
Electron beam metal melting and the formation of a penetration zone are caused by the pressure of the electron flow in the electron beam gun, the release of heat in the volume of the solid metal, the reactive pressure of the evaporating metal, secondary and thermal electrons, and radiation.
Welding is performed by a continuous or pulsed electron beam. Pulsed beams with a high energy density and pulse frequency of 100-500 Hz are used in the welding of volatile metals such as aluminum and magnesium. This increases the penetration depth of the metal. The use of pulsed beams allows you to weld thin metal sheets.
In the chamber that forms the electron beam, air is pumped up to pressures of 1-10 Pa. This leads to high protection of the molten metal from air gases.
Electron Beam Welding Techniques
In electron beam welding, the following techniques are used to improve the quality of the weld:
- inclined beam welding (5-7 ° deviation) to reduce pores and discontinuities in the metal;
- welding with an additive for alloying weld metal;
- dispersed-lined welding to improve the output of vapors and gases from the metal;
- narrow cutting welding;
- welding with two electron guns, with one gun melting the metal, and the second forms the root of the channel;
- preliminary passages for cleaning and degassing the edges of welded metals;
- double-sided welding simultaneously or sequentially;
- scanning of an electron beam: longitudinal, transverse, X-shaped, circular, ellipse, arc, etc .;
- beam splitting for simultaneous welding of two or more joints;
- modulation of the beam current with a frequency of 1-100 Hz. to control the heat supply to the weld.
Benefits
Electron beam welding has the following advantages:
- High concentration of heat allows you to weld metals from 0.1 to 200 mm thick in one pass;
- For welding, 10-15 times less energy is required than for arc welding;
- There is no saturation of molten metal with gases.
Weaknesses
- The formation of imperfections and cavities in the root of the seam;
- The need to create a vacuum in the working chamber.
Equipment
Electron beam installations are divided into universal and specialized, high-vacuum (pressure less than <10 -1 Pa), intermediate vacuum (pressure 10-10 -1 Pa), welding in shielding gas (10 3-10 5 Pa), chamber (welding product inside the working chamber) and with local evacuation (product sealing in the welding zone).
The structure for electron beam welding includes an electron gun, power supplies. The electron beam gun forms an electron beam with a high energy density.
See also
- Electron beam melting
- Electron gun
- Electron beam
Notes
Literature
- Nikolaev G. A. Welding in mechanical engineering: a Handbook in 4 volumes. - M.: Mechanical Engineering, 1978 (1-4 tons).
- Electron beam welding / About. K. Nazarenko, A. A. Kaydalov, S. N. Kovbasenko et al. / Ed. B.E. Paton .-- Kiev: Naukova Dumka, 1987 .-- 256 p.
- Z. Schiller, W. Geisig, Z. Panzer. Electron beam technology. - M .: Energy, 1980 .-- 528 p.
- Popov V.F., Gorin Yu.N. Processes and installations of electron-ion technology. - M .: Higher. school, 1988 .-- 255 p. - ISBN 5-06-001480-0 .
- Vinogradov M.I., Maishev Yu.P. Vacuum processes and equipment of ion - and electron-beam technology. - M .: Engineering, 1989 .-- 56 p. - ISBN 5-217-00726-5 .