Antifriction -1. Possessing a low coefficient of friction. 2- Intended for manufacturing parts functioning in friction and sliding conditions 3- Conducive to reduce friction between the parts of the mechanism.
Antifriction material possesses resistance to wear during prolonged friction. It is used to cover friction surfaces (for example, in plain bearings). For example, brass, iron-graphite, bronze or babbitt can function as such materials. These materials should possess a minimum coefficient of friction, the coating structure should provide anti-solidification and the possibility of quick running-in to the counterbody, the materials' mechanical prosperities should correspond to operational loads, should be sufficiently wear-resistant and ductile. The process of applying antifriction coatings must ensure that the same requirements are met comparing to wear-resistant coating, the only difference is that during this process the coating thickness is not strictly limited.
Due to the fact that there is a small amount of materials having the necessary antifriction features, in order to reduce friction lubricants are used, which is the most frequently used type of materials that are capable of changing friction coefficient.
Antifriction carbon materials (composite materials) are obtained by processing graphite. The following grades are manufactured: antifriction heat-treated material of AO grade, antifriction graphite material of AG grade, antifriction materials impregnated with babbitt, tin and lead of АО-1500B83, АО 1500СО5, АG-1500B83, АG-1500СО5, Nigran, Himanit grades and and graphitoplast materials of AFGM, AFG-80VS, 7B-2A, KV and AMS grades. Antifriction carbon materials are made from non-calcined petroleum coke, coal tar pitch with the addition of natural graphite. To obtain a dense impermeable antifriction material, it is impregnated with metals.
Using this method, antifriction materials of АG-1500B83, АG-1500СО5 АMG-600B83, АMG-600СО5 grades and others of their ilk are obtained. Permissible operating temperature in air and in gaseous environments containing oxygen for AO - 250-300 ° C, for AG - 300 ° C (in reducing and neutral environments AO-1500 and AG-2500 ° C). Carbon antifriction materials are chemically resistant in many aggressive gas and liquid environments. They are resistant to almost all acids (up to the boiling point of acid), in salt solutions, in all organic solvents; and limitingly resistant in concentrated solutions of caustic alkalis.
Bearing- a product that is part of a support or abutment that supports a shaft, axis, or other movable structure with a given stiffness. It fixes the position in space, provides rotation, rolling or linear displacement (for linear bearings) with the least resistance, perceives and transfers the load from the moving unit to other parts of the structure.
The main characteristics of bearings:
The maximum dynamic and static load (radial and axial);
The maximum speed (revolutions per minute for radial bearings);
bearing accuracy class;
bearing recourses before signs of fatigue, in revolutions;
The main types of bearings according to the principle of operation:
gas dynamic bearings;
Crucible (VIII-IX century)
the process of pouring metal from a crucible into a casting mold
Continuous casting machine
The graphite crystallizer
Carbide insert-working surface of various tools, equipment.., which require special functioning conditions. For further information, please visit the “Hard alloys” section.
Crucible - it is a container, a vessel for heating, drying, burning, calcining or melting various materials. A distinctive feature of crucibles is the presence in their design of refractory materials that are highly resistant to various influences of metals and alloys. The crucible is usually conical (truncated cone) or cylindrical in shape. A variety of crucibles are also melting cups, melting boats.
Crucibles are used in the following fields:
metallurgy - melting, roasting, burning, casting of metals, fluxes, ore concentrates;
metalworking - casting, annealing, etc.
laboratory equipment - dissolution, burning, melting, weighing, etc.
chemical industry - dissolution, burning, melting, homogenization, etc.
Materials used in the production of crucibles:
general refractory materials (fireclay bricks) - melting and bottling of ferrous metals, fluxes;
oxide refractory materials - corundum, zirconium oxide, chromium oxide, cerium oxide, yttrium, aluminum, beryllium oxide, and others;
graphite - bottling, firing of non-ferrous metals;
quartz - fused and sintered quartz;
basalt - melted basalt;
tantalum - metallurgy of lanthanides;
heat-resistant glass - Pyrex, Simax, and others;
porcelain - chemical resistant porcelain;
platinum - precise chemical work, operations with hydrofluoric acid, etc.
gold - especially precise chemical work
Crucible melting - crucible process, the process of obtaining metals and their alloys in liquid form in pots of refractory materials - crucibles. C.m. - the oldest method of melting metals (copper, bronze). Aristotle wrote about crucible smelting of steel (4th century BC). The process was used mainly in the countries of the Ancient East (India, Persia, Syria, etc.). Crucible steel was used to produce edged weapons (including damask blades), sharp knives and durable tools. In later centuries, the secret of crucible melting of steel was lost. Crucible melting was again used in Europe in the 18th century. by B. Gentsman (England, 1740). C.m. reached its greatest development in the 1st half of the 19th century.
The main methods of crucible melting for a long time remained unchanged, but the process was the subject of research and improvement. The Englishman D. Mushet discovered the beneficial effect of manganese on steel and began to add manganese oxides to the crucible charge - he introduced the steel deoxidation operation (1801). S. I. Badayev invented the furnace, combining 2 departments - cementation and crucible, in which work was carried out in turn. In the method he proposed (1808), cementation of iron first occurred and then the resulting steel was melted. P.P. Anosov, working on the production of damask steel, opened the process of gas cementation of iron during crucible melting. (1837). The simultaneous implementation of both processes (cementation and melting) reduced the duration of the steel production process to 9-10 hours instead of several days. The main feature of the method of P. M. Obukhov (1857) was the use of iron ore in crucible melting, which ensured that steel with a constant composition was obtained when the starting materials were different in carbon content. Large steel mills based on the Obukhov method appeared in Russia - in Zlatoust (1860), Perm (1863) and St. Petersburg (1865). Although crucible steel was expensive and the process was inefficient, it remained for a long time the only material for the manufacture of critical tools and parts of mechanisms, Crucible melting occupied a leading position in the production of high-quality steels until the discovering of the electric steel-smelting process. By the middle of the 20th century Crucible steel production continued in Sweden. Its main purpose is the manufacture of high-quality tools. С.m. Is also used in non-ferrous metallurgy (mainly in small foundries and repair shops) for the production of non-ferrous metal alloys or for the melting of metals and alloys before casting molds.
Chill mold, permanent mold- a metal, graphite or ceramic template (different from the ingut mold) of two or more parts, which is used repeatedly to produce a large number of castings of the same shape and can withstand from 100 to 10,000 fillings. Castings made of cast iron, steel, copper, brass, aluminum, magnesium and other alloys are obtained in chill molds. Chill molds can be without a slit, with one or more slots in the horizontal and vertical planes and with a combined slit plane, depending on the configuration of the casting. The outer surface of the casting is formed by the sockets of the chill mold, the inner cavity by sand and metal foundry cores.
To fill the chill mold with melt in the plane of the connector or in the sand core there are channels of the gating system. The opening and closing operations of parts of the chill mold are usually automatized- they are performed by special chill machines. To increase the durability of the chill mold and reduce the cooling rate of the casting, special coatings and paints are applied to the working surfaces of the chill mold.
Chills covered with a thin layer (up to 0.5 mm) of the facing mixture of fine sand, binders and water serve to produce castings of a simple configuration with high surface density and tightness. Lined chill molds coated with molding sand only in specially prepared recesses serve for the manufacture of large castings of cast iron and steel weighing several tons. According to State Standart GOST 17819-72, the chill mold is a metal form that is filled with liquid metal under the influence of gravitational forces.
Continuous casting machine (also called strand casting machine). Nowadays, about 60% of billets cast by continuous casting are cast on slab continuous casting machines. Liquid steel is continuously poured into a water-cooled mold called a crystallizer. Before starting casting, a special device with a locking grip (so-called “seed”) is introduced into a crystallizer, serving as the bottom for the first portion of metal. After the solidification of the metal, the seed is pulled out of the mold, pulling the formed ingot. The flow of liquid metal continues and the ingot is constantly growing. Only the surface layers of the metal solidify in the crystallizer, forming a solid shell of the ingot, which preserves the liquid phase along the central axis. Therefore, a secondary cooling zone, also called a second crystallization zone, is located behind the crystallizer. In this zone, as a result of forced surface cooling, the workpiece hardens over the entire cross section. This ingot formation process is a method for producing ingots of unlimited length.
In this case, in comparison with casting into ingot molds, the metal loss for trimming the ends of ingots sharply decreases, which, for example, when casting mild steel, is 15-25%. In addition, due to the continuity of casting and crystallization, a complete uniformity of the ingot's structure along its entire length is achieved.
There are 4 CCM designs:
By the number of creeks, CCM is divided into 1-7 creeks.
Depending on the geometry of the ingot, the continuous casting machine is divided into:
-it’s an apparatus or mold for crystallizing any substance,
- apparatus for the separation of solids during cooling of solutions or melts,
- in metallurgy, a water-cooled mold for accelerated solidification of molten metal (used in continuous casting plants or continuous casting machines, in electroslag remelting plants and in vacuum arc furnaces ..,
- a shallow glass cylindrical vessel for crystallization. ...
Types of crystallizers by type of application:
The crystallizer of CCM, UNRS - is designed to receive molten metal entering it from the tundish, as well as to convert part of the molten steel into a solid state through intensive heat removal by cooling water. Steel from the tundish gets into the mold either with an open stream or by supplying it under the metal level with the help of an immersion nozzle.
The graphite crystallizer is used in non-ferrous metallurgy, for continuous horizontal and vertical casting machines (Outocumpu, UPcast, Rautomead, Hormesa, Metatherm, UNGL, MNL -140), for the production of wire rod, circle, strip, hexagon, pipes and other non-ferrous metal profiles ( copper, bronze, brass, aluminum). Due to such properties of graphite as: low gas permeability, high surface strength, lack of interaction with liquid metals and alloys, high thermal conductivity, low porosity ... it is possible to obtain metal and alloy billets with good surface quality.
Drum Flacker - a plant used to process material from a molten state into a solid product of a certain shape. The solidification of the molten material occurs due to its cooling to the crystallization temperature. Nowadays, several types of solidified melt are used: plates, lozenges and granules.
Electrode.The term electrode was proposed by Faraday to replace the more general term "poles" for special cases. It follows that the electrode may have positive pole characteristics; Faraday called this electrode the anode, and the electrode with the characteristics of the negative pole was called the cathode.
Electrodes are used as:
A part of an electrochemical system, in electrochemistry - including a conductor (metal or semiconductor) and the solution surrounding it (for example, a Hydrogen electrode, a Silver chloride electrode, a Reference electrode, a Glass electrode). A conductor by which a part of an electrical circuit formed by wires is connected to a part of a circuit passing in a non-metallic medium (ionic liquid, ionized gas, etc.). A structural element through which an electric current is supplied somewhere, for example, a welding or furnace electrode, an electrode in electroencephalography.
ELECTRODES USED IN INDUSTRIAL FIELDS:
EG grades are used on arc steel-smelting furnaces, refining furnaces, ferroalloy furnaces and ore-thermal furnaces;
EGP grades are used on high power arc steelmaking furnaces and ladle furnace installations;
EGSP grades are used on heavy-duty electric arc furnaces and ladle furnaces.
Imported graphite electrodes have their own markings.
Сutting graphite electrodes (also called plates, rods) are made of graphite of the GE grade, which is obtained in the same way and has the same physical and mechanical properties as the material of graphite electrodes for electric arc steel-smelting furnaces. Graphite electrodes are used for arc cutting of a thick layer of metal - when cutting armored vehicles, removing surface defects on castings (burns, bays, bloating, etc.), in iron and steel production.
Graphite electrodes for electroerosive piercing machines serve as a tool whose shape corresponds to the shape of the part. These electrodes burn out the necessary shape. The electrode is made of isostatic graphites (for example, I-3 (ISEM-3), made in Japan).
Welding electrode - a metal or nonmetallic rod of electrically conductive material, designed to supply current to the welded wares. Currently, more than two hundred different brands of electrodes are produced, more than half of the entire range of products being made up of consumable electrodes for manual arc welding.
Welding electrodes are divided into consumable and non-consumable . Non-consumable electrodes are made of refractory materials such as tungsten according to State Standart GOST 239480 "Tungsten welding electrodes non-consumable", synthetic graphite or electrical coal.
The consumable electrodes are made of a welding wire, which according to State Standart GOST 2246-70  is divided into carbon, alloyed and highly alloyed . A layer of a protective coating is applied over a metal rod by pressure molding. The role of the coating lies in the metallurgical treatment of the weld bath, protecting it from weathering and providing more stable arc burning.
Metal welding electrodes
And the others
Were used in the early stages of the development of welding technology.
Now are used as continuous wire for welding in the environment with shielding gas
casting in chill molds
Foundry relates to hot metal processing. The essence of this process lies in the fact that the molten metal of a certain chemical composition fills the mold - a cavity, which in its shape and size corresponds to the configuration of the required cast blank or part (casting). After solidification of the metal, a casting is obtained.
Foundry makes it possible to obtain castings of various sizes and weights, of a wide variety of configurations, with small processing allowances. Casting is the simplest, fastest and cheapest industrial method of producing blanks having a complex geometric shape.
Types of casting:
in sandy molds (manual or machine molding)
multiple (cement, graphite, asbestos forms);
into shell shapes;
in shapes of meltable models;
in shapes of frozen mercury models;
in the chill mold;
according to gasified (burnable) models;
casting with warming
crystalline graphite (ore)
graphite electrodes for smelting metals (EG)
MPG graphite bushings
thermally expended graphite foil
Graphite - (named by a mineralogist in 1789 from the Greek word graphein, "write"). The translation of the word is associated with a pencil. And that’s true, as an inner core of a simple pencil (lead) consists of natural graphite mixed with special glue. So what is graphite? Graphite is a mineral from the class of native elements, one of the allotropic modifications of carbon (C). Other forms of carbon (C): diamond, graphite, fullerene, graphene, i.e. there is only one chemical element, but the substances from it are different. How can it be possible? For example, diamond and graphite have a different structure of the crystal lattice (this phenomenon is called polymorphism). Another kind of allotropy: the formation of molecules with a different number of atoms, for example oxygen: atomic - O, molecular - O2, ozone - O3. People used natural Graphite even in ancient times. There is evidence that it was used for tattooing. In Egypt, about 4,500 years ago, graphite was used as jewelry and pigment for coloring ceramics. Graphite pencils first appeared only in the XII century in the East. In Europe, with the flowering of fine art in Italy during the Renaissance, graphite began to be used by everyone in human activity.
The first European industrial production of "black chalk" (pencil) was located in the Italian province of Piedmont, where its first deposit had been found. Writing cores made of graphite immediately gained incredible popularity in Europe, but immediately went up in price, since the deposit in Piedmont was quickly exhausted. The same thing happened to graphite deposits that were found in Andalusia and Thuringia. And only in the XVI century a large deposit of "black chalk" was finally discovered in England. The British used not only wood, but also gold in pencil production, decorating pencils with different traceries. Such pencils were a true piece of art and were very expensive. Such pencils were a true piece of art and were high-prices. Substances with similar external physical properties were often mistaken for graphite, as, for example, Molybdenite (a mineral of molybdenum disulfide),
which has been considered graphite once. Other names for graphite are: "black lead", "carbide iron", "silver lead". In 1779, Carl Scheele discovered that graphite can be oxidized with air to form carbon dioxide and claimed graphite as a "special mineral coal."
There are two types of graphite: natural and artificial - it's necessary to understand. Why is graphite so widely used in various fields of human activity nowadays? The answer to this question is based on several unique properties:
- high electrical conductivity (close to metals)
- resistance to aggressive environments (chemical inert)
- resistance to high temperatures (refractoriness, heat resistance - melting point 3800 - 3900 ° С)
- high thermal conductivity (higher than that of copper and aluminum).
Depending on which properties are needed more, different grades of graphite are produced ...
Natural graphite. There are 2 types of graphite in nature: crystalline and cryptocrystalline.
After ore dressing, natural graphite looks like a powder (various shades: gray, silver, black), resembling gunpowder. the following grades of commodity natural graphite are received:
Low ash grades of natural graphite (Russian production)
GAK-3 State Standart GOST 10273-79-designed for the manufacture of active masses, alkaline batteries and masses for graphitized antifriction products from non-ferrous metals.
EUT-1,2,3. State Standart GOST 10274-79, EUZ, EUN-designed for the production of electric coal wares.
GK-2,3. State Standart GOST 4404-78-designed for the manufacture of pencils clerical, school and copy groups.
GE-3,4. State Standart GOST 7478-75- designed for the production of current sources.
P, GS-4. State Standart GOST 8295-73- designed for the manufacture of greases, coatings and electrically conductive rubber.
Common grades of natural graphite:
GT - 1, 2, 3. State Standart GOST 4596-75, GO - TU 5728-001-74206540-2005- designed for the manufacture of refractory, graphite-ceramic wares.
GE - 1, 2. State Standart GOST 7478-75-
designed for the production of primary chemical current sources.
GL - 1, 2, 3. State Standart GOST 5279-74; GL, GLM - TU 5728 -002-74206540-2005- designed for the manufacture of paints, pastes and dust used in foundry.
Artificial graphite is used because of its unique properties, but the importance of a certain property depends on the conditions. For example, if the conditions require electrical conductivity, the customer will need graphite EG. Therefore, there are so many grades of artificial graphite. Artificial graphite, in contrast to natural, is always solid, of various shapes (cylinder, cube, parallelepiped) and sizes. Artificial graphite may be obtained using various technique: Acheson's, recrystallization, pyrolysis, etc. In industrial production, the most common technique is Acheson's. By applying this technique in various technological combinations, the following types of graphite are obtained:
Electrode graphite - This graphite is used to make graphite electrodes, which are used for melting metals and cutting a flake of metal billets, and graphite lining. Graphite electrodes grades: EG, EGP, EGPK, EGSP, RP, НP, SHP, UHP.
Nipple joints of grades: N, NU, NS, RPN.. GDB-Graphite domain block.
coal-containing graphite-(mainly used in the aluminum industry, main feature is a lower carbon content (up to 74%) and higher hardness), EU-coal electrodes, CB-cathode blocks, AB-anodes, DBU-coal- graphite domain blocks.
Structural graphite-GMZ, GMZ-PP- Low-ash graphite, coarse graphite for all practical purposes,
3OPG, 3OPG-PP-Impregnated, dense structural heat-treated graphite with the improved structure.
MG, MG-1 PP 7-3, MG-1 PP 7-2, L-7 fine-grained graphite that possesses high mechanical strength
Graphite MPG, MPG-6, MPG-7-fine-grained heat resistant graphite that possesses high mech anical strength
Graphite ISEM-1 (I-1), ISEM-2 (I-2), ISEM-3 (I-3), IG-12, SED-40(C-4),R4340, EDM, СDI- Isostatic structural fine-grained heat resistant graphite that possesses high mechanical strength. The scope of structural graphite grades is very wide: metallurgy, machinery, chemical, jewelry, food, printing industry ...
In order to obtain special properties, further processing of graphite is done.
Antifriction graphites are made from non-calcined petroleum coke and coal tar pitch with the addition of natural graphite, soot. To obtain a dense impermeable antifriction material, it must be impregnated with the following metals: babbitt, tin and lead. Following grades of artifial graphite are produced: (Russian production):
AO- artificial heat-treated graphite, АО-600, АО-1500, АО-1500B83 (with Babbitt), АО -1500SО5 (lead, tin), Nigran, Himanit, AG - antifriction graphite: AG-600, AG-1500, AG-1500 B83, AG-1500SO5, AMG-600B83, AMG-600SO5.
They are used for parts of friction units operating in conditions of dry, semi-dry and liquid friction under a calm or smoothly changing load (compressor o-rings, liners, pump bearings, etc.)
Materials from graphitoplast: AFGM, AFG-80VS, 7V-2A, KV, KM, AMS, ATG-S, ATM-1. These materials are made on the basis of fluoroplast-4 material. These materials are used in friction units of various machines and equipment operating in aggressive environments and high temperatures, as a protective material from aggressive environments.
Thermally expanded graphite is made from natural crystalline graphite. At the first stage, it is oxidized. The oxidation in this process is the implantation of molecules and ions of sulfuric or nitric acid in the presence of an oxidizing agent (hydrogen peroxide, potassium permanganate, etc.) between the layers of the crystal lattice of graphite. Oxidized graphite is washed and dried. Then oxidized graphite is subjected to heat treatment to T = 1000 ° C at a rate of 400-600 ° C / s. Due to the extremely high heating rate, there is a sharp release of gaseous decomposition products of the embedded sulfuric acid from the crystal lattice of graphite. As a result, the interlayer distance increases by approximately 300 times, and the number of small graphite particles and the sample volume increase by 60–400 times. A certain amount of sulfur or nitrogen oxides remains in the obtained material (this depends on the technology used). Next, the obtained thermally expanded graphite is rolled, sometimes reinforced and pressed to obtain wares. Thermally expanded graphite is mainly used in the production of flexible foil and graphite gasket material, as well as graphite seals based on them, such as different types of gaskets, stuffing rings, etc.
Siliconized graphite is a mixed material consisting mainly of silicon carbide (SiC) and free carbon (C), i.e. it is a product of high temperature treatment of various types of artificial graphite with molten silicon.
It is used for the manufacture of various wares, materials that are resistant to oxidizing and gas environments at high temperatures. Silicon carbide gives siliconized graphite heat resistance, and graphite gives high resistance to multiple tempreture changes and self-lubricating ability.
Siliconized graphite grades: SG-T; SG-P; SG-M; GAKK 55/40.(Russia)
Pyrolytic graphite - is formed by thermal decomposition on a hot surface (under carefully controlled external conditions) of a gaseous hydrocarbon – methane CH4. As a result of these processes methane decomposes, and gaseous carbon condenses on a hot surface with a temperature of 2300 to 2600 K. At a lower temperature, the reaction proceeds very slowly, while at a higher temperature, the reverse process occurs - the interaction of carbon with hydrogen and methane. This grade is much denser and gas-tight than ordinary grades of graphite. The density of ordinary graphites is 1.6-1.8 g / cm3, while in pyrographite it reaches 2.22 g / cm3; Its shell with a thickness of 0.03-0.05 mm does not allow helium to penetrate even when heated to 2500 ° C. Its mechanical strength <5-10 times higher than that of normal graphites and at operating temperatures it is higher than that of heat-resistant steels or nickel alloys.
The only drawback of Pyrolytic graphite is its large coefficient of linear expansion, which, when heated, causes the substrate to rupture under the pyrographite shell. To prevent this phenomenon, several percent of silicon carbide (boron, hafnium, cobalt, niobium) is implunted into Pyrolytic graphite. Stronger and significantly harder materials are obtained (however, its thermal conductivity is increased). The burning rate of pyrographite when interacting with a high-temperature air flow is almost 104 times lower than that of conventional grades of graphite. This is probably due to the high surface density of Pyrolytic graphite, which significantly reduces the reaction area. It has heat-insulating properties, therefore it is recommended for sheathing hypersonic aircraft, shields, plasma torch parts and rocket parts in contact with hot gases, etc. Isotropic Pyrolytic graphite (IPG) is available in the form of plates, cuvettes, rings, washers, segments and other products of various configurations. The analysis showed that pyrographite has a highly oriented crystal structure. In some cases, all graphite layers are almost parallel to each other. Such graphite can be both natural and artificial. Artificial, called highly oriented pyrolytic graphite or HOPG.
It is useful for scanning probe microscopy. HOPG is the “natural” standard for scanning probe microscopy. Due to the fact that the distance between the layers is known exactly, it is possible to calibrate the SPM according to the obtained image of the surface of graphite.
Graphite crucibles that are used in induction furnaces. By design, induction units can be divided into the units with top casting and those with bottom casting. Of course, graphite crucibles of various designs are used in these furnaces. In particular, for crucibles for a bottom casting method, an additional stock-stopper plug is required. Some stocks have an internal hole for a thermocouple to control the temperature of the metal drain. If such a hole is provided in the wall of the crucible, then the locking stock-stopper plug is made solid.
Graphite for crucibles, that are used in induction furnaces. EGP Graphite- Impregnated EG graphiteIt is slightly more stable than conventional electrode graphite. The advantage of such crucibles is its low price, the disadvantages are that it is the coarse-grained graphite (grain size from 2 to 4 mm) and its low resistance to oxidation - graphite grains fall into the melt.
MG graphite- this is fine-grained graphite of Russian production. The grain size is 0.8mm. Possess fairly high rates of durability.
MPG- It is a dense graphite produced in Russia. It has the highest resistance and is the finest grains (grain size 0.025 mm). It has a high resistance to burning.
High-density isostatic graphites - superior in quality to MPG grade graphite produced in Russia. Grain size up to 0.010mm. They have the highest oxidation resistance.
Graphite scrap - graphite production waste, graphite electrode cinders after use,
broken graphite electrodes, pieces of various grades of graphite of irregular shape, graphite wares after use, etc. It is used for further processing into the other products or graphite chips of various fractions (carburizer).
Graphite blades are widely used in dry friction compressors and rotary vane pumps.
Graphite blades gained their popularity due to the unique properties of the material (graphite):
Reactionary stability, which means the ability of the material not to change its properties, being in the zone of influence of external unfavorable factors (in this case, the temperature arising in the process of friction), the ability to work at temperatures up to 500C; Chemically inert, which means having the ability not to interact with other chemicals; self-lubrication — this process occurs due to the presence of the smallest particles of graphite forming a lubricant in the gap between the pump chamber and the blade, this occurs due to the hexagonal structure of the crystal lattice of graphite.Due to the reduced friction, the graphite blades produce a low noise level while compressor or pump is functioning. Graphite blades in dry environments in many aspects are superior than blades made from textolite or other reinforced plastics. Blades made of carbonite, graphite-fluoroplastics, oxophene and other composite materials are usually used in humid environments.
For the manufacture of blades, isostatic grades of graphite are used, which are specially created for working conditions in rotary vane compressors and pumps. The most frequantly used graphite grade is ISEM-3 (I-3), Japanese production.
Blades are a part of pumps and compressors.
To read more about the way these apparatus work please visit the "rotary vane compressors and pumps" section.
Billets from VK8
Hard alloys - ard and wear-resistant metal materials capable of preserving these properties at 900-1150 ° C. They are made on the basis of carbides of tungsten, titanium, tantalum, chromium at various contents of cobalt or nickel. There are sintered and cast hard alloys.
Sintered hard alloy is obtained by powder metallurgy and can only be processed by grinding or physicochemical processing methods (laser, ultrasound, etching in acids, etc.),
Cast hard alloy is intended for surfacing on the equipped tool and not only mechanical, but often heat treatment is applied to it (tempering, case hardening, precipitation hardening).Powder carbide is fixed on the equipped tool by soldering or mechanical fixing. Hard alloys are also distinguished by the carbide metals present in them: tungsten - VK2, VK3, VK3M, VK4V, VK6M, VK6, VK6V, VK8, VK8V, VK10, VK15, VK20, VK25; titanium-tungsten - T30K4, T15K6, T14K8, T5K10, T5K12V; titanium-tantalum-tungsten - ТТ7К12, ТТ10К8Б. Tungsten-free ТНМ20, ТНМ25, ТНМ30
Carbide inserts have HRA 86-92 and possess high wear resistance and red hardness (800-1000 ° C), which allows processing at cutting speeds of up to 800 m / min.
Nomenclature of sintered hard alloys:
Flexural strength (σ), mPa
Thermal conductivity (λ), W /(m*C)
Young's modulus (Е), hPa
Ingot mold - mold filled with molten metal to produce an ingot. Molds can be made of metal, clay, gypsum, earth, graphite and are used for casting molten metal. By design, they are divided into bottle, solid-bottom and through; By the method of pouring metal - filled on top and bottom (siphon casting). For casting iron on casting machines, horizontal ingot molds are used, and for casting ferroalloys and some non-ferrous metals - in the form of low trapezoidal bathtubs, sometimes with vertical partitions.
The mold is a necessary attribute of a jewelry workshop. The mold for precious metals is small and made of cast iron, steel or graphite. Sometimes they are covered with a protective coating.
Induction furnace are used for melting gold, silver, copper, bronze and other metals. it is an electrical furnace in which the heat is applied by induction heating of metal. a graphite crucible is the heater in these furnaces, it is heated by currents. Induced currents heat only the crucible and the metal placed in it. Energy costs and are very low and melting doesn't take much time. The advantages of induction furnaces are: constant readiness to work, long term of operation, low maintenance cost and the ability to reach high temperatures.
a graphite mold for the "bath" welding-VR28
The mold for the "bath" welding of fittings is a product for welding various reinforced profiles. As a rule, they are made of copper or various grades of graphite, as these materials are the most suitable judging by its thermolysis and other physical and mechanical properties. The process of "bath" welding fittings is divided into:
mechanized (the process of "bath" welding of reinforcement, in which the welding wire is supplied to the welding zone automatically, and the arc or holder is controlled manually.);
manual (the process of "bath" welding of reinforcement, in which the electrode material in the form of a single (piece) electrode is fed into the welding zone manually).
Reinforcement welding can be of two types: vertical and horizontal, so the shape is also vertical or horizontal.
VR-20,22,25,28,32,36,40 (diameter of reinforcement) - vertical for manual bath welding;
GR-20,22,25,28,32,36,40 (diameter of reinforcement) - horizontal for manual bath welding;
VM-20,22,25,28,32,36,40 (diameter of reinforcement) - vertical for mechanized bath welding;
GM-20,22,25,28,32,36,40 (diameter of reinforcement) - horizontal for mechanized bath welding.
For unconditional joints, molds may be made according to individual customer drawings.
Mold for casting - is a fixture in the foundry for castings.
The variety of manufactured castings necessitates the use of various molds that differ in manufacturing technology and source materials. Depending on the number of times of use, the molds are divided into one-time, semi-permanent and permanent types of molds.
One-time molds are used to produce one or more castings, if several castings are simultaneously formed in the mold. After pouring the melt and solidification of the castings, the molds are destroyed. For the manufacture of one-time molds, sand-clay, sand-resin mixtures or mixtures consisting of sand, clay and special additives and binders are usually used. One-time molds can be moist, dry, dried, chemically hardening, semi-permanent and permanent.
Semi-permanent molds are made of highly refractory materials (fireclay, graphite, asbestos, etc.). They are used for the manufacture of simple shapes (ingot molds, pallets, plates, etc.) of large steel and cast iron castings. The cooled cast is removed from the mold, and the mold is not destroyed. After a small repair, the mold can be used for repeated pouring (several dozen times).
Permanent molds withstand pouring from several hundred to several tens of thousands of times. They are made of steel and cast iron, and in some cases of copper and aluminum. Metal permanent molds are used in mass and large-scale production to produce castings by centrifugal or coking methods, as well as for injection molding.
Galvanized steel fittings
Shaped products — sample, in accordance to which something is sewn. External shape, model of any wares. Thus, “Shaped products” are products associated with a certain shape given to them in accordance with any template, sample, model, drawing, sketch. Or simply, these are the products with complex shapes.
Shaped products are used in:
In the shoe and clothing industry - an example of the model by which clothes, a hat, shoes, etc., are made, i.e. the external shape of the product;
Metallurgy, pipe production - these are elbows, tees, flanges, plugs, fixed supports and other elements which main intentions are to connect pipes during installation of pipelines;
Metallurgy shape steel - rolled stock is a type of steel in which a tangent to at least one point in the contour of the transverse section crosses it.
Fuel and energy complex and utilities - they play the role of any profile parts: casts, smokers, parapets, and much more, made of galvanized or stainless steel, copper, aluminum with a thickness of 0.4 to 1.5 mm;
Construction - brick, which has the default shape of a rectangular parallelepiped, can be made in various smoothed, elongated, uneven shapes. This means that it will have a different shape than the standard one.
Shaped graphite products are used in many areas of human activity due to the unique properties of graphite.
(Visit the “products” section)
Sleeve - a part of a machine, a mechanism, a device of cylindrical or conical shape (with axial symmetry), which has an axial hole into which the mating part enters. Depending on the purpose,
bearing sleeves, adapter sleeves, etc., are used. Adapter sleeves- a tool used in metalworking equipment to install tools with different Morse tapers. On a lathe, the adapter sleeves are used to install the tool in the tailstock, in the fixed center in the headstock. For a milling machine, the adapter sleeve is the main adapter element, which can significantly reduce the cost of technological preparation of production.
Graphite sleeve is used as a rolling-element bearing, as a sealing element, in aggressive environments, and at high temperature.
graphite electrodes for smelting metals (EG grade)