"We will make your ideas come true"
- Development and manufacture of components for power engineering.
- Repair of components for steam and gas turbines.


+38 (0562) 39-69-72
+38 (067) 637-39-68
Language
 
 
 


 


Technologies

Electron-beam welding


Method of electron beam welding based on the use for heating and melting of the parts to be welded beam energy of fast - moving electrons of the electron beam.


The electrons emitted from the emitter-cathode, are accelerated by the electric field of high tension to high speeds comparable to the speed of light, and are focused into a narrow beam directed from the emitter to the welding product, which is the anode.


The process of electron beam welding is performed in vacuum not lower than 10-4 mm. of the mercury pillar, as otherwise most of the energy of the electrons will be spent on heating and ionization of the gases of the surrounding atmosphere. Faced with the surface of the anode (work piece), the electrons decelerate and give their kinetic energy to the product in the form of heat.


The electron beam, if it has a good focus, is a highly concentrated source of heat, that provides a narrow and deep zones of penetration (depth of 50 mm with a width of 6-8 mm). Due to the fact, that the process of electron beam welding takes place in a vacuum, it creates the most favorable conditions to reduce the gas saturation of the weld metal.


Equipment of the electron beam welding


The main part of the equipment of the electron beam welding is a welding electron gun, which serves for receiving and accelerating the electrons and for focusing the electron beam. The gun is placed in a vacuum chamber, where is installed the piece being welded and the mechanism for moving the workpiece at a speed that is required for welding. The vacuum in the installation of electron beam welding is created with the help of pumps.


The using of electron beam welding


This method is used for welding of the pure metals, active and refractory metals, it is highly sensitive to the effects of the gases of the surrounding atmosphere such as W, Mo, Ta, etc.


Due to the difficulties of creating a vacuum cameras of the large size in this way are welded, mostly, not very large items. Some similarities with the electron beam welding has welding by the coherent light beam that is generating by a special source — laser. Powerful light beam with an extremely high concentration of energy may melt, weld, burn, cut the metals and other materials. Vacuum is required. The processed material can be removed far from laser.


In electron beam welding is used the energy of the focused electron flow for heating and melting metal. Electron beam welding is used for welding of thick piece with a small distance between them.


The method provides a greater depth of penetration at a very small width of the seam. Electron beam welding is used in cases where it is impossible to connect products other way. Additionally, it allows you to perform welding at the high speed. When the equipment is operated with the filament electrodes are emitted, the electron flow is controlled (focuses and concentrates) by magnetic lenses. The electron beam is created the same way like a light beam in a television receiver. The energy of electron beam welding is controlled by the current that is supplied to the filament.

Electron beam welding is mainly produced in a vacuum, as air molecules interfere with the movement of the beam. The vacuum camera is protected against radiation, appearing in the welding process. The welder controls the process thru the optical system and controls the beam with the help of remote control system.

The electron beam welding has significant advantages:

The high concentration of the heat input into the product, which stands out not only on the product surface, but also at a certain depth in the volume of the base metal. Focusing of the electron beam can be obtained spot heating with a diameter of 0.0002 -5 mm, which allows for single pass welding of metals with a thickness of several tenths of a millimeter to 200 mm.


As a result you can get a weld joint, in which the ratio of depth of penetration to width to 20:1 or more. There is a possibility of welding of refractory metals (tungsten, tantalum, etc.), ceramics, etc. Decrease in the length of area of thermal effect decreases the probability of recrystallization of the base metal in this area. A small amount of the inputing warmth


As a rule, to obtain an equal depth of penetration during electron beam welding is required to enter heat 4 to 5 times less than in arc welding. As a result of sharply reduced warpage of the product. The lack of saturation of the molten and hot metal gases. On the contrary, in a number of cases observed degassing of the weld metal and increase its plastic properties.


The result is a high quality welds of the reactive metals and alloys such as: niobium, zirconium, titanium, molybdenum, etc. Good quality electron beam welding is also achieved at low carbon, corrosion-resistant steels, copper and copper, nickel, aluminum alloys etc.

.png

Vacuum ion-plasma deposition of coatings

Characteristics of high-speed vacuum ion-plasma magnetron sputtering:

Energetical value of atom that is evaporated from the surface of the metal during operation of the magnetron is from 250 to 1500 eV/at, besides on 1 argon atom with E = 500 eV stands out 0.6-0.7 of titanium atoms.

This is somewhat worse than at the arc sputtering, but the specific power > 40 W/cm2 results in an additional evaporation and sublimation of the material, which reduces the energetical value of evaporated atoms.

Vacuum ion-plasma deposition of coatings is an environmentally clean coating technology, that is different by the high power density of the plasma discharge from 40 to 500 W/cm2 and the high speeds sputtering of the thin pellicles from 10 to 100 mkm/h, and more, which opens new possibilities of ecologically safe physical methods of deposition materials.

hdrmtech.gif

The technology has the following advantages compared with existing methods of coating:

• sputtering all types of materials: conductors, semiconductors, carbon and ceramic materials;
• wide range of deposition velocities: 0.1 to 100 mkm/h and above;
• high quality and uniformity of the coatings, including multi-component and multi-layered, both the composition and in the layers;
• the same speed of sputtering of dissimilar materials from one target of mosaic type;
• high precision of design of the mosaic composition of the targets and the sputtering coatings;
• low prime cost of process and obtainment of the targets;
• complete environmental safety (no liquid effluents, gaseous emissions, transportation and storage of toxic reagents).

The technology is safe for humans and the environment, is a natural substitute of environmentally harmful chemical and electrochemical coating methods; thus it provides at the comparable performance and the prime cost higher quality coatings and exceptionally wide range of sputtering materials, compounds and composites that can be received by the chemical methods.

Arc ion-plasma technologies

Characteristics of the arc ion-plasma technologies:

Energetical value of atom that is evaporated from the surface of 50 eV/at for Cadmium and 850 eV/at for Wolframium.
- The average performance of the material in the arc 3x1018 at/Kl for Cd and 0,2x1018 at/Kl for W.
At the average current in the stationary arc 100A the performance, for example, for titanium will 7x1019 at/sec ~ 20 g/hr. In this case, if sputtering of the coating on the area of 1000 cm2 is possible to achieve the productivity of 50 mkm/hour.

arctech.gif

When the vacuum arc is ignition, contraction occurs on the target of the cathode with the formation of the cathode spot from which steam escapes evaporated material, that is ionized in an electric field near the cathode. The generated plasma is almost completely ionized and consists of multiply charged ions and droplet phase of the target material, the proportion of which for the fusible metal is ~10%, and refractory metals ~1%.

To remove drops are used the special separators.

The using arc vacuum ion-plasma technologies:

Wear-resistant coatings for toolmaking and mechanical engineering.
The creation of heat-resistant, corrosion-resistant, erosion-resistant coatings for aircraft gas turbine engines and turbines, compressors, power plants.

To implement of the arc ion-plasma technologies use arc evaporators with high speed coating. For them, the average current on one evaporator in various designs ranges from 50 to 500 A, indicating promising applications of arc evaporation of metals for the problems of high-speed coating.