The silicon carbide crucible is a bowl shaped container with a deep ceramic bottom. When solid is heated by fire, crucible must be used, because it can withstand high temperature more than glassware. This is also the reason why the silicon carbide crucible is used by the public. First of all, the use of the silicon carbide crucible is introduced, hoping to help everyone.

　　The crucible usually does not fill the melt too much to prevent the heat from jumping out and allowing the air to pass in and out freely to allow for possible oxidation. Because the bottom of the crucible is very small, it is usually needed to be heated directly by the fire on the mud triangle. The crucible can be placed on the iron tripod by either positive or oblique, and can be set up according to the requirements of the experiment. The crucible must not be placed on the cold metal table immediately after heating so as to avoid its rupture due to rapid cooling. You can't put it on the wooden table immediately to avoid burning the desk or causing fire. The correct method is to cool the holder on the iron tripod or to cool it on the asbestos net.

　　In some solid in high temperature processing, we need to use the crucible, because compared to ordinary glass crucible can withstand higher temperatures, here mainly recommended silicon carbide crucible, following on from the North carbon graphite products manufacturers to introduce the industrial value of silicon carbide crucible.

　　As the name suggests, the main raw material of silicon carbide crucible is silicon carbide, and the main characteristic of SiC crucible is due to silicon carbide. SiC is also called emery, chemical formula is SiC, it is made of quartz sand, petroleum coke (or coal tar), sawdust and other raw materials through the resistance furnace high temperature smelting materials. SiC content in silicon carbide is about 95% of the black silicon carbide has a strong toughness, high temperature characteristics, silicon carbide crucible is made of the black silicon carbide, silicon carbide crucible at high temperature in the process of using low thermal expansion coefficient, for rapid heating and cooling has good anti strain performance, good to have pH the corrosion resistance is a good chemical stability of the products. Silicon carbide crucible has good performance in metallurgical, mechanical, chemical and other industrial sectors depending on its good performance.

　　The performance of the silicon carbide crucible is good. It has good performance in metal smelting and alloy smelting, and has excellent technical and economic results in industry.

　　Beijing Great Wall Co., Ltd is dedicating on crucible over decade and hope to supply the best to our dear clients.

　　Electric arc furnace steelmaking is based on electrodes to generate arcs, so that electric energy can be changed into heat energy in the arc, melting furnace burden and removing impurities such as sulfur and phosphorus, adding necessary elements (such as carbon, nickel, manganese, etc.) to smelt steel or alloy with various properties. Electric energy heating can accurately control the temperature of the furnace and produce low temperature waste gas. The heat efficiency of the arc steelmaking furnace is higher than that of the converter.

　　Technology development has a history of about 100 years in EAF steelmaking, although other methods always face the steelmaking challenges and competition, especially the high efficiency oxygen steelmaking impact, but the proportion of steel production of EAF steelmaking in the world steel output is still rising year by year. In the early 1990s, steel produced by EAF in the world accounted for 1 / 3 of the total steel output. In some countries, EAF was the main steelmaking technology in some countries, and the proportion of steel produced by EAF smelting was 70% higher than that in Italy.

　　In 1980s, widespread in the EAF steel production in continuous casting, and gradually formed a "energy-saving production process of a scrap preheating electric arc furnace smelting a refining continuous casting a continuous rolling, arc furnace is mainly used for rapid equipment scrap as raw material of steel-making. In order to fundamentally overcome the ultra high power AC arc furnace arc instability, three-phase power supply and current unbalance and severe impact on the power grid and the research of DC arc furnace, and put into industrial application on first Century 8O in the mid-1990s, DC arc furnace using only 1 root of the graphite electrode has been widely used in the world in 90s (2 with some graphite electrode DC arc furnace).

　　Greatly reduce the consumption of graphite electrodes is the greatest advantage of the DC arc furnace, before the end of 1970s, AC arc furnace per ton of steel consumption of graphite electrode in 5 ~ 8kg, graphite electrode costs accounted for 10% of the total cost of steel to 15%, although taken a number of measures, so that the graphite electrode consumption decreased to 4 6kg, or production costs accounted for 7% 10%, the use of high power and ultra high power steelmaking method, electrode yak is reduced to 2 ~ 3k.g / T steel, DC arc furnace which uses only 1 graphite electrode, graphite electrode consumption can be decreased to 1.5k.g / T steel under.

　　Both theory and practice show that the single consumption of graphite electrode can be reduced by 40% to 60% compared with the AC arc furnace.

　　Graphite heat exchanger is a heat transfer device made of graphite. The graphite in the manufacture of heat exchanger should be non transparent, and is often used in the non - permeable graphite and graphite.

　　Characteristic

　　Graphite heat exchanger has good corrosion resistance, heat transfer surface is not easy to fouling, heat transfer performance is good. However, the graphite is easy to crack, the bending and tensile strength is low, and it can only be used for the low pressure, even though the pressure is the best piece of porous structure, the working pressure is generally only 0.3 ~ 0.5 mpa.

　　Graphite heat exchanger with high cost, large size, use is not much. It is mainly used in the heat transfer of corrosive media such as hydrochloric acid, sulfuric acid, acetic acid and phosphoric acid, such as the condenser of acetic anhydride and acetic anhydride. Mainly used in the chlor alkali chemical industry, petroleum chemical industry, fluoride salt, titanium dioxide, zirconium, chloroacetic acid, chlorinated paraffin, monocrystalline silicon fluorine

　　Structure

　　The graphite heat exchanger can be divided into 3 types: block type, tube shell and plate type according to its structure. A piece of hole: a plurality of bulk graphite assemblies that are formed by a plurality of holes. Shell and tube type: tube shell type heat exchanger in graphite for heat exchanger occupies an important position, according to the structure is divided into two kinds of fixed and floating head. Plate: made of graphite bonding plate heat exchanger. In addition, there are immersion, spray type and sleeve type, etc. (see snake tube heat exchanger, sleeve type heat exchanger). Graphite heat exchanger has good corrosion resistance, heat transfer surface is not easy to fouling, heat transfer performance is good. However, the graphite is easy to crack, the bending and tensile strength is low, and it can only be used for the low pressure, even though the pressure is the best piece of porous structure, the working pressure is generally only 0.3 ~ 0.5 mpa. Graphite heat exchanger with high cost, large size, use is not much. It is mainly used in the heat transfer of corrosive media such as hydrochloric acid, sulfuric acid, acetic acid and phosphoric acid, such as the condenser of acetic anhydride and acetic anhydride.

　　Graphite tubes are divided into synthetic resin impregnation, water glass impregnation, and pitch impregnation according to their different materials.

　　Classification

　　1.A piece of hole: a plurality of bulk graphite elements are assembled in a plurality of holes.

　　2.tube shell type: tube shell type heat exchanger in graphite for heat exchanger occupies an important position, according to the structure is divided into two kinds of fixed and floating head.

　　Shell and tube heat exchanger (shell and tube heat exchanger) is also called tubular heat exchanger. Is to close the bundle in the shell wall as heat transfer surface heat exchanger. The structure of the heat exchanger is simple and reliable, and can be made of various structural materials (mainly metal materials), and can be used in high temperature and high pressure.

　　3.The panel: made of graphite plate bonded plate heat exchanger. In addition, there are immersion, spray type and sleeve type, etc. (see snake tube heat exchanger, sleeve type heat exchanger).

　　Heat exchanger is a metal sheet with a corrugated shape by a series of stacked a new high-efficiency heat exchanger. A thin rectangular channel is formed between the plate and plate, and the heat exchange is carried through the half piece. Heat exchanger is an ideal heat exchange equipment for liquid - liquid, liquid - vapor. It has the characteristics of high heat transfer efficiency, small heat loss, compact structure, small size, convenient installation and cleaning, wide application, long service life, etc.. Under the same pressure loss, the heat transfer coefficient is 3-5 times higher than that of tubular heat exchangers, and the area of the tube type heat exchanger is 1/3, and the heat recovery rate can be as high as 90%.

　　Graphite gaskets that made by pure graphite plate or metal (teeth plate, plate, net) reinforced graphite plate cutting or stamping, has many excellent sealing performance, such as: thermal stability, self lubrication, corrosion resistance, aging, not brittle, etc., in the harsh conditions of the conditions can be used for a long time, very few need to maintain. Lining material can be different with different metal plate. Type optional without edge, inner edge, out sourcing side, inside and outside wrapping. Graphite cut gasket is from pure graphite plate punching or cutting into the, it has good corrosion resistance, resistant high / low temperature, good compression elasticity and high strength, a variety of circular complex geometric gasket is widely used in pipes, valves, pumps, pressure vessels, heat exchanger, condenser and generator, air compressor, exhaust pipe, a refrigerating machine.

　　Raw materials

　　Expandable graphite (flexible graphite) is made from pure natural graphite by chemical treatment and high temperature of 1000. This material provides excellent heat resistance and chemical resistance. It can be very good to make gasket with high elasticity and low ductility.

　　Features

　　1, flexible graphite gasket in the extremely low temperature to 400 degrees within the high temperature range of sealing performance almost unchanged;

　　2, flexible graphite gasket almost all of the liquid has excellent chemical resistance (except for the strong oxidizing acid, etc.);

　　3, due to the cold deformation and ductility is very small, tight installation has no effect on the flexible graphite gasket.

　　Graphite gasket classification

　　Flexible graphite gaskets are made of flexible graphite sheets (or metal reinforcing), and are divided into four types according to the application requirements:

　　1, flexible graphite gasket: cutting from the flexible graphite sheet, used for pipe flange and valve cover, etc.. It is recommended that the gasket is a small diameter washer, which depends on its low mechanical strength.

　　2, flexible graphite gasket Mi: the hook of the steel sheet (0.2 mm thick) by a flexible graphite sheet is clamped in the middle, and then is cut into a certain size, mechanical strength is very high.

　　3, flexible graphite gasket PM: flexible graphite sheet is adhered to the 0.2 mm thick 304 stainless steel sheet with high mechanical strength and easy to transport, because it can also be cut into a complex shape, this gasket is widely used in various industries.

　　4, flexible graphite gasket PM-A: the T/#1215 stainless steel sheet for 316 steel (50 micron).

　　Pipe flanges for all kinds of industries, heat exchangers, valve covers, etc., as well as the special shape of the level gauge, the flange.

　　Graphite gasket to stone line materials, warp knitting and shaping. Graphite gasket used for high temperature, high pressure, strong corrosive medium under the work of all kinds of valves, pumps, reaction kettle and other equipment of the stuffing box sealing.

　　Flexible graphite is a soft sheet form of compressed natural graphite made from exfoliated mineral flake(crystalline) graphite. Due to its flexible texture, it is referred to as flexible graphite to distinguish it from other forms of graphite materials: flake graphite, amorphous graphite, artificial graphite (hard graphite), graphite electrodes, graphite/carbon fiber, etc.

　　standard flexible graphite sheet product suitable for most industry applications. As gasket material, it is usually fabricated into Graphite Laminate, reinforced graphite sheet and widely used in fluid sealing applications: flange gasket, spiral wound gasket, heat exchanger gasket, etc. It can also be used as solid lubricant in metal stamping and forming applications, or as heat liner in industry furnaces and other heating devices.

　　Sometimes flexible graphite is also referred to by a manufacturer's brand name like grafoil. Flexible graphite sheet is made with pure expanded graphite. standard flexible graphite sheet product has a high purity of 99.0% carbon content. Higher carbon content gives the flexible graphite foil better chemical resistance, better thermal conductivity, and better sealing ability.

　　graphite gasket sheet is made with pure flexible graphite sheet reinforced with glass fiber insert. The both sides are pure graphite sheet, the reinforced material is one layer or two layers of glass fiber. The graphite layer and glass fiber are jointed together with glue bonded. Reinforced graphite gasket is cut or molded from our reinforced graphite sheets. Inner and outer eyelet with SS304 or SS316.

　　Graphite gaskets having excellent corrosion resistance, high temperature resistance, excellent compressibility and recovery, widely used for piping, valves, pumps, pressure vessels, heat exchangers, condensers, generators, compressed machine, exhaust pipes, chillers. Graphite reinforced gasket can also cut into any shape of complex gaskets such as water gauge gasket, full face flange gasket and automotive cylinder head gasket.

　　Reinforced materials: stainless steel tanged, stainless steel foil, tinplate, wire mesh, glass fiber and and Aluminium foil.

　　As all we know that carbon fiber is high strength and extremely light weight. It is the most commonly used composite fabric with applications in all areas of industry now, such as household applications, machines ,aerospace,spaceflight and other high-tech applications.Carbon fiber fabric has super knitting technology and exact molding technics and equipments, so we can produce full carbon series products to meet all kinds of process requirement on composite materials.

　　The advantages of our carbon fiber fabric cloth sheet:high tensile strength and ray penetration ; abrasion and corrosion resistance;high electric conductivity,soft and free to cut;light weight, easy to construct and little increasing the weight on constructed based materials; high elastic modulus;wide temperature range; type: 1K, 3K, 6K, 12K, 24K; good surface, factory price;Standard width we produce is 100mm,any other width can be customized

　　; Other fabric area weight can be avaible.

　　The 12k carbon fiber fabric cloth sheet is a new material, it has the obvious advantage of high tensile strength, abrasion resistance, corrosion resistance, good conductivity, and high temperature resistance. Carbon fiber fabric can be compatible with epoxy, vinyl, polyester and other resins. It shows incredible mechanical performance and reinforcing effect on structures.

　　Our carbon fiber fabric cloth sheet can be used in the following areas:airspace,sporting goods,mechanical equipment,shipbuilding,automobile,advertising panels; construction,increase building use load; material aging;concrete strength grade is lower than the design value; structural cracks processing;harsh enviroment service component repair,protective;other purposes:industrial products and many other fields.

　　We also produce the aramid and carbon hybrid fabric which is woven by aramid and carbon fiber , which combine the advantages of high tensile strength from carbon fiber and impact resistence from aramid fiber. Aramid and carbon hybrid fabric have extensive applications, such as automotive engineering, motor sports, the fashionable decorations, aircraft construction, ship construction, sports equipments, electronic products and other applications.

　　The crack after the quenching is the biggest defect of graphite mold in the process of heat treatment, it will make the processed graphite mold scrap and the production and economic loss.

　　The causes of the crack: there is serious network carbide segregation in graphite mould material ;there is mechanical or cold plastic deformation stress in the graphite mould; graphite mold heat treatment improper operation (heating or cooling too fast, quenching cooling medium selection improper, cooling temperature is too low, cooling time is too long, etc.) ; the graphite mold has complex shape, uneven thickness, sharp corners and threaded holes, which makes the thermal stress and the tissue stress too large ; graphite mold quenching heating temperature is too high, overheating or over burning ; the graphite mold quenching after tempering is not timely or tempering insulation time is insufficient ; graphite mold repair quenching heating, without intermediate annealing again heating quenching ; graphite mold heat treatment, improper grinding process ; there are high tensile stress and micro cracks in hardened layer after edm.

　　The preventive measures: controlling the internal quality of graphite mold raw material strictly ; improving forging and spheroidizing annealing process, eliminating mesh, ribbon, chain carbide, improving the uniformity of spheroidizing structure ; the graphite mold should be stress annealing after the mechanical processing or cold plastic deformation (>600 degrees) after the heating quenching ; For complex shape graphite mould, asbestos should be used to block thread hole, wrap dangerous section and thin wall, and adopt graded quenching or isothermal quenching ; repair or renovation of graphite mold, it need to be annealed or high temperature tempering ; the graphite mold should be preheated in quenching heating, take pre-cooling measures when cooling, and choose the appropriate quenching medium ; controlling the quenching heating temperature and time strictly to prevent graphite mold overheating and over burning ; the graphite mold should be tempered timely after quenching, holding time should be sufficient, high alloy complex graphite mold should be tempered 2-3 times ; Choosing the correct grinding technology and suitable grinding wheel ; improving the graphite mold EDM process, and stress relief tempering.

　　Graphite crucible has good thermal conductivity and high temperature resistance. It has small thermal expansion coefficient and has a certain strain resistance to hot and rapid cooling in the process of high temperature use. The corrosion resistance of acid and alkaline solution is strong, and it has excellent chemical stability. It is widely used in metallurgy, casting, machinery, chemical industry, smelting of alloy tool steel and smelting of nonferrous metals and their alloys, and has better technical and economic results.

　　Our company can machine all of the sizes the graphite crucibles for different application with the molded graphite or isostatic graphite materials. We can machine the graphite crucibles according to the customer’s dimension requirements or drawings accurately.

　　Many of the customers will need the large size graphite crucibles such as 100kg, 150kg even 500kg capacity. That will be our graphite silicon carbide crucibles.it can be used in various industrial furnaces, such as vaccum furnace, induction furnace, sintering furnace, soldering furnace, ion nitriding furnace, vacuum quenching furnace, tantalum niobium smelting furnace etc. This graphite crucible can be used for various non-ferrous metal smelting, such as aluminum, gold, silver, copper, precious metal etc.

　　The advantages of our large size graphite crucibles:.Large sizes, different sizes design according to customer’s requirements; Max temperature resistance 3200 C degree; High purity, Good strength; Graphite crucible can be treated by special coating process, resists oxidation and maximizes service lifespan; Exact machining of graphite crucibles.

　　The large size graphite crucible for melting copper has a long service life, but it is also built on the basis of routine maintenance. For example, although the graphite crucible has high temperature resistant performance, but if we do not pay attention to the cooling,sometimes it will affect their use and life, such as a cold water poured directly above the cooling is not desirable.

　　The isostatic gaphite rod and block formed by means of cold isostatic pressing (CIP) technique, isostatic graphite is characterized by its homogeneous structure and excellent isotropic electrical, thermal and mechanical properties.

　　Its features are as following: Fine grain; Homogeneous structure; Isotropic properties;High density and high mechanical strength;High thermal and chemical resistance;High resistance to thermal shock; Proper electrical conductivity;Higher oxidation resistance; Lower ash content.

　　Sometimes it is purified in special-designed graphitization furnace to remove non-carbonaceous impurities. It is widely used in various industrial and scientific engineering as a structural and/or functional material.

　　The graphite block rod can be used for making graphite plate, graphite tube, graphite crucible, graphite rotor and shaft and so on. It widely used in electron industry, chemical industry, mechanical industry, aviation industry, manufacturing industry, metallurgic industry and so on, such as anode, cathode, bipolar plate, vacuum furnace, water treatment, hydrogen fuel cell, electrode, casting, glass factory, heat conduction, lubricant, mold industry, vacuum pump.

　　High purity isostatic graphite rod and block is mainly used for electrodes, anodes, cathodes, heating elements, resistors, fluxing/degassing tubes, molds, crucibles, special structural parts, etc. in metallurgy, mechanical engineering, chemical & electro-chemical industry, energy management, glass & ceramics, transportation and other industries.

　　Its detailed applications are as below :Molds in continuous casting systems for making shaped steel, cast iron, copper; Sintering molds for cemented carbides, diamond tools and electronic components; Molds for making shaped glass; Crucibles for melting precious metals or alloys; Electrodes for EDM;Heating elements, heat shields, crucibles, boats in furnaces for pulling monocrystalline silicon or optical fibers; Anodes for production of manganese dioxide, metallic magnesium and rare metals.

　　Our company also produce other grade graphite materials such as molded graphite , extruded graphite and vibrated graphite.please contact us for the further discussion if you have the demands of our graphite block rod or other products.

　　Graphite is an allotrope of elemental carbon around each carbon atom connected with the other three carbon atoms (the arrangement of a plurality of hexagonal honeycomb type) by covalent bond, covalent molecular composition. Because each atom emits an electron, the electrons are free to move, so the graphite belongs to the conductor. Graphite is one of the softest minerals, and its uses include the manufacture of pencil cores and lubricants.

　　Found that graphite parts life tend to be much shorter than expected life often in the production of silicon, due to the replacement of graphite device number and electric energy consumption of the graphite calcinations, in addition to increase production cost of enterprise, but also restricts the effective capacity of volatile. Next, TEGW CARBON GROUP will tell you that this situation occurs mainly in the following aspects of the reasons:

　　1, material selection is wrong

　　Because of the different roles of graphite in the thermal field, the material used will be different. Usually, the electrode, connecting rod, heater, heater screw, graphite crucible, draft tube, draft tube support ring and heat preservation cylinder should be manufactured by isostatic pressing and high strength graphite material, so as to meet the actual needs of production.

　　Other parts, such as chassis, reflector plate, leak proof plate, upper cover plate and so on, can be produced by extrusion or graphite with medium coarse structure. The premise is that the production can meet the production requirements.

　　2, the design is unreasonable

　　In the use of graphite parts, some graphite problems appear to occur and accidents, in fact, many are caused by defects in the design.

　　Therefore, in the design of graphite parts, in addition to consider the level of the material itself, specifications, but also must take full account of the strength of graphite parts in use, and to determine its geometric size.

　　3, improper use

　　In the use of many graphite parts, the rupture of graphite crucible occupies a large proportion, and the improper use is the main reason that cannot be ignored in the cause of this situation.

　　Under normal circumstances, 1 18 "or 20" of the graphite crucible available about 45 heats, but very much although graphite crucible problem did not occur in the design, material selection, processing, calcinations, but still very short service life, and some of the graphite crucible after the breakdown from the section view far reaching its natural loss they should have.