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.

　　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.

　　The graphite material can be divided into coarse grain structure, fine grain structure and fine grain structure from the structure , distinguished from molding method, it mainly can be divided into vibration molding graphite ,extruded molding graphite , molded graphite and isostatic pressing graphite.

　　As all we known , the molded graphite material with high purity, low ash content , its carbon content is over 99.9%, it is a good choice of making crucible and other high quality products.at the same time, it has low ash,high thermal stability and high thermal conductive.It could be used in arc furnace as heat element. The using life is longer than the metal. And it has good oxidation resistance. It is easy to install and reduce the cost. Our graphite block also could used as raw material. It could be make crucible,mould and other graphite products.

　　The advantages of the graphite material:Fine grain,the grain size of our isostatic graphite material can be several micron; Homogeneous structure; High density; Excellent thermal conductivity; High mechanical strength; Proper electrical conductivity; Minimum wettability to molten metals; Grain size, ash content, bulk density, electrical resistivity, bending strength, compressive strength, all can be customized.

　　The application of the our graphite materials:Molds, chutes, sleeves, sheathes, linings, etc; in continuous casting systems for making shaped steel, cast iron, copper, aluminum; Sintering molds for cemented carbides and diamond tools; Sintering molds for electronic components; Electrodes for EDM; Heaters, heat shields, crucibles, boats in some industrial furnaces (such as furnaces for pulling monocrystalline silicon or optical fibers); Bearings and seals in pumps, turbines and motors.

　　Our company can provide all kinds of the graphite materials which are in different applications.please feel free to contact us if you are interested in any of our products or would like to discuss a custom order. We are looking forward to forming successful business relationships with new clients around the world in the near future.

　　　　The graphite material has the characteristics of ablation resistance, thermal shock resistance and so on. It is used in the long tail nozzle of air to air missile, and is the main material for the structural parts of the engine throat. The requirements of the parts size and appearance of high technology, but because of its special material, cutting performance, processing quality, especially in the easy processing of edge collapse defects, these have become a bottleneck of non metal processing.

　　In recent years, various types of engines, long tail nozzle, graphite parts processing tasks heavy, high technical requirements. Based on the analysis of the scrap graphite parts for the past year, it is found that the scrap produced by the part of the workpiece is about 20%., because the material is difficult to be machined and the processing efficiency is low, which makes the production progress of the parts seriously affected.

　　In order to solve the problem of edge collapse graphite parts as soon as possible, improve the production efficiency of graphite parts, based on a certain type of air-to-air missile, and the front thimble throat component shell combination and other mechanical processing as the research object to conduct technical research, explore the Shi Mocai material processing technology from the aspects of processing method, cutter and its cutting parameters, solve the problem of machining parts of compacted graphite. Non metal processing technology, has important significance for scientific research and production tasks successfully completed.

　　Cubic boron nitride is prepared by high temperature and high pressure. The material is a kind of six party boron nitride with a similar structure to graphite. Compared with synthetic diamond, this material has a lower hardness, but it has good thermal stability. It is suitable for processing ferrous metals and difficult to process materials. Cemented carbide has higher hardness and better wear resistance, but it is hard to sharpen the blade. Therefore, three kinds of cutting tools, such as synthetic diamond, cubic boron nitride and cemented carbide, are chosen for cutting comparison. In order to choose the appropriate cutting parameters corresponding to the three cutting tools, a thorough cutting test was carried out: Due to the speed limit of the machine itself, the linear speed of cutting can be between 130m/min~150m/min.

　　In summary, we can see that:

　　(1) the machining of graphite parts adopts diamond cutting tools, the processing effect is better, and the durability is the highest.

　　(2) graphite material should be processed with low speed, small feed, cutting parameters, roughing and finishing methods, not only can prevent the collapse of the edge, but also more conducive to improving tool durability.

　　(3) the method of "parallel cutting" can guarantee the surface quality of parts and improve the processing efficiency.

　　Similar to the super capacitor, ultra-thin graphene nano materials excellent conductivity can form two-dimensional conductive contact with the particle electrode active material of lithium ion battery, constructing three-dimensional conductive network in the electrode, which can greatly improve the battery performance. The experimental results show that graphene conductive additives can greatly reduce the internal resistance of battery, improve the high rate charge and discharge performance of the battery, and prolong the battery cycle life; also can increase the capacity of active material g play, so as to improve the battery capacity; can also reduce the amount of conductive agent, is conducive to the design of high energy density batteries; in addition, containing graphene the conductive agent battery in high rate discharge in the process of heating is relatively small, the surface temperature of the battery is relatively lower, which is conducive to improving the safety of the battery.

　　Taking commercial lithium iron phosphate material as an example, low conductivity is the most important factor restricting its electrochemical performance. Based on the excellent conductivity of graphene, Liu Zhaoping proposed a new method for the modification of lithium iron phosphate by using graphene instead of conventional pyrolytic carbon. The synthesis of graphene / LiFePO4 composite cathode materials with spherical micro nano structure, including graphene uniformly coated lithium iron phosphate nanoparticles, and the formation of a three-dimensional conductive network in the two micron particles (Figure 3). Compared with carbon coating, graphene modification can significantly improve the rate performance and cycle stability of lithium iron phosphate. The work also provides useful guidance for the structural design and modification of other electrode materials.

　　In addition, graphene can also be coated on the foil collection fluid to form graphene functional coating aluminum foil. The coating using conductive graphene excellent and unique two-dimensional nanostructure, can significantly reduce the interfacial resistance between sheet and foil, and can improve the binding force between the active material and the current collector, and the collector can inhibit corrosion in a certain extent, so the new type collector can make the battery rate discharge capacity and cycle life has been further improved.

　　Graphene material has entered the stage of application and verification of downstream battery enterprises, but its cost problem still restricts its large-scale application. Although the cost of graphene has been greatly reduced in recent years, there is still a big gap compared with the traditional conductive carbon black and graphite. In the lithium industry severe downward pressure of the environment, the problem of graphene is still the development of low cost and high quality to be solved.

　　Graphene is an allotrope of carbon in the form of a two-dimensional, atomic-scale, hexagonal lattice in which one atom forms each vertex. It is the basic structural element of other allotropes, including graphite, charcoal, carbon nanotubes and fullerenes. It can be considered as an indefinitely large aromatic molecule, the ultimate case of the family of flat polycyclic aromatic hydrocarbons.Graphene and its band structure and Dirac cones, effect of a grid on doping

　　Graphene has many unusual properties. It is about 200 times stronger than the strongest steel. It efficiently conducts heat and electricity and is nearly transparent.[3] Graphene shows a large and nonlinear diamagnetism,[4] greater than graphite and can be levitated by neodymium magnets.

　　Scientists have theorized about graphene for years. It has unintentionally been produced in small quantities for centuries, through the use of pencils and other similar graphite applications. It was originally observed in electron microscopes in 1962, but it was studied only while supported on metal surfaces. The material was later rediscovered, isolated, and characterized in 2004 by Andre Geim and Konstantin Novoselov at the University of Manchester. Research was informed by existing theoretical descriptions of its composition, structure, and properties. This work resulted in the two winning the Nobel Prize in Physics in 2010 "for groundbreaking experiments regarding the two-dimensional material graphene."

　　Graphene is a transparent and flexible conductor that holds promise for various material/device applications, including solar cells, light-emitting diodes (LED), touch panels and smart windows or phones. For example, Graphene-based touch panel modules produced by a China-based company (2D Carbon Graphene Material Co., Ltd) have been sold in volume to cell phone, wearable device and home appliance manufacturers.

　　The toxicity of graphene has been extensively debated in the literature. The most comprehensive review on graphene toxicity summarized the in vitro, in vivo, antimicrobial and environmental effects and highlights the various mechanisms of graphene toxicity.[290] The toxicity of graphene is dependent on factors such as shape, size, purity, post-production processing steps, oxidative state, functional groups, dispersion state, synthesis methods, route, dose of administration and exposure times.

　　Graphene nanoribbons, graphene nanoplatelets and graphene nano–onions are non-toxic at concentrations up to 50 µg/ml. These nanoparticles do not alter the differentiation of human bone marrow stem cells towards osteoblasts (bone) or adipocytes (fat) suggesting that at low doses graphene nanoparticles are safe for biomedical applications. 10 µm few-layered graphene flakes were able to pierce cell membranes in solution. They were observed to enter initially via sharp and jagged points, allowing graphene to enter the cell. The physiological effects of this remain uncertain, and this remains a relatively unexplored field.

　　Graphite materials can be divided into natural graphite and artificial graphite, natural graphite powder and because more shape so its application is limited, so the development of high pure graphite becomes more and more important; the application of high purity graphite in the photovoltaic production with the rapid development of photovoltaic industry in recent years and the rapid warming.

　　With the rapid development of solar photovoltaic industry, the import of raw materials and polysilicon monocrystalline silicon solar battery demand is increasing in recent years, a large scale production of monocrystalline silicon polysilicon processing factory and processing factory as needed so like bamboo shoots after a spring rain built; production of monocrystalline silicon and polycrystalline silicon raw materials are increasing, and the high pure graphite is the raw material an important one, the development of high pure graphite also promote high-quality silicon and polysilicon production, therefore high purity graphite plays an important role in the photovoltaic industry.

　　With the continuous development of solar photovoltaic industry, the production process of solar energy photovoltaic materials in the raw material needs are also increasing, so according to the development direction of the photovoltaic industry of graphite materials should be studied according to the characteristics of the photovoltaic industry characteristic, its future development direction should be from the following aspects:

　　Graphite solar photovoltaic industry is in need of superfine, high purity and other characteristics, so it can be fine, high purity as the two core problems of deep processing of graphite to study, have certain effect in different ways on the purification process of crushing graphite, stripping is conducive to the protection of large scale purification of graphite, but the grinding medium corrosion loss directly influences the effect of acid purification method. The comminution and purification process should be designed as the whole process to avoid the interference of human factors and produce high purity ultrafine stone powder.

　　The current photovoltaic industry in the production of graphite materials resistant to high temperature, but the service life is not long enough, the production of more supplies; hence the need for further development of new graphite material, so that it can maintain the existing high pure graphite high temperature and oxidation characteristics, can enhance the mechanical strength and prolong the service life. This can reduce the amount of graphite consumption in solar photovoltaic production, greatly reducing the cost of solar photovoltaic production.

　　To carry out the research and application of high pure graphite composite materials, carbon materials, high purity graphite and isostatic graphite materials such as more and more are studied, some properties of the high pure graphite could improve materials used in photovoltaic industry production, the high pure graphite material as the foundation of the material is improved the mainstream of the future direction of development.

　　Graphite has excellent physical, chemical and mechanical properties, and has been widely used in metallurgy, machinery, electronics, national defense, aerospace and other fields. According to experts estimate, by 2020, the global demand for natural graphite will be added to 2 million 600 thousand tons, new power, new materials and other new rapid development of the industry, but also to the graphite industry has brought new opportunities for development. Industry advocates, the next step should be in establishing and improving the relevant professional management system together, will be the main capital of graphite to strategic heights.

　　China is a big producer of graphite, and its capital reserves are rich. According to industry experts, China graphite capital mainly distributed in Heilongjiang, Inner Mongolia, Shandong, Hunan, Shanxi (soil shaped graphite) and Jilin, which is the largest crystalline graphite reserves in Heilongjiang Province, accounting for about 57.87% of national reserves, followed by Shandong, Inner Mongolia, Henan and Sichuan; Hunan Province, the largest reserves of graphite, followed by Jilin, Shaanxi, Fujian and Anhui.

　　Data show that in 2013, China's natural graphite output value of 810 thousand tons, accounting for 68% of global output. "International graphite recorded proven reserves calculation, Chinese graphite reserves ranked first in the international, National Engineering Research Center, said Professor Wang Xuequn, the skills of deep processing of metal mine in 2014, China output of 650 thousand tons of natural flake graphite, including the production and operating data and customs data, Chinese output has reached 610 thousand of natural flake graphite 2017 will exceed 700 thousand tons tons..

　　The first National Non-metallic Mineral Processing Engineering Research Center Professor He Baoluo and other experts believe that, the iron and steel industry, foundry industry is the largest use of graphite, annual production of over 300 thousand tons, there will be a contraction in the future; secondly, the use of big flake graphite preparation expansion stone processing paper, ink, graphite graphite gasket and sealing materials, graphite packing, insulation materials, annual demand over 200 thousand tons, the future trend will add.

　　The future of the graphite industry is very broad. One is the traditional category of industrial structure optimization and upgrading and constantly pulling new category of graphite spent widening, is to add some commodity future market graphite; two is to follow the Chinese vigorously carry out energy-saving environmental protection, new energy, biotechnology, high-end equipment manufacture, new materials, new power cars and other strategic new industries, and femoral graphite industry the rapid development of. "Natural graphite, the low price for the aphanitic graphite quotation, used to produce low-end graphite products, the future cost of adding graphite occupation in the first category of photovoltaic, semiconductor materials, lithium batteries and fuel cell etc.."

　　Special graphite covering a wide range of industry have different understanding and classification of carbon products Chinese industry, electrical carbon products of natural graphite products industry and metallurgy, metallurgy is used to explain the classification of carbon products, special graphite mainly refers to high strength, high density, high purity graphite products (referred to as the three high graphite). From the three high graphite material structure can be divided into coarse grain structure, fine grain structure and fine grain structure of three kinds of molding methods are distinguished from molding special graphite, extrusion molding and special graphite isostatic pressing special graphite three categories, in addition, vibration molding can also be used in the production of special graphite. High quality special graphite, an isotropic graphite, is a kind of special graphite produced by isostatic pressing.

　　Not all special graphite must achieve the same high density, high strength, high purity indicators, special graphite used in different occasions, has a specific intensity, density requirements, that is, strength, density index is not the same. Many special graphite do not need to achieve high purity, ash is not the main quality index. Some special graphite does not need high strength and high density, but it needs high purity. Some special graphite, such as EDM graphite, according to different processing technology and processing objects, require different physical and chemical indicators of fine particles, graphite or superfine particles, structural graphite.

　　Special graphite for electrical discharge machining

　　EDM is a new processing technology in machinery manufacturing industry, EDM of many high hardness metal processing, and processing of complex shape, high precision parts, can be used as a tool for the anode copper material, also can use graphite materials. As a tool for EDM, the graphite material of electrode must meet the following conditions:

　　(1) the structure is compact and the tissue is homogeneous; there should be no coarse particles and large pores;

　　(2) with high mechanical strength and good processability, it can work out complex shapes or sharp angles and flakes;

　　(3) the graphite tool electrode has a certain loss in the process of EDM, and this loss should be as low as possible;

　　(4) the discharge characteristics are stable and the processing speed is faster. Therefore, graphite with fine grain structure or graphite with fine particle structure is generally used in EDM, and the physical properties of graphite are best isotropic. Therefore, the graphite material with fine grain structure is the most popular graphite material used in China's electrical discharge machining.

　　There are many kinds of graphite products, such as ordinary graphite, impregnated graphite, fine graphite, high purity graphite, isostatic graphite, and a very special kind of graphite, that is, electric spark, graphite, or EDM graphite!

　　EDM graphite is mainly used in the production of dies. It has excellent properties that copper metal can not match. The electric spark graphite itself has the characteristics of non-metallic material, and it also has some characteristics of metal. Electric spark graphite density is smaller than copper, light quality, can bring many benefits to production; easy processing; from hardness, electric spark graphite is 1/3 of copper metal; and conductivity is less than metal copper;

　　The high temperature resistance of electric spark graphite is better than that of copper metal. The melting point of copper is more than 1300 degrees, while the melting point of electric spark graphite is about 3800 degrees. High melting point can be greatly reduced, after the electronic pulse produced by a large number of high temperature, so that melting itself, causing sublimation phenomenon. In addition, the electric spark graphite processing is simple, and the production speed is fast, and the production capacity is not to be worried!

　　EDM is a new processing technology in machinery manufacturing industry, EDM of many high hardness metal processing, and processing of complex shape, high precision parts, can be used as a tool for the anode copper material, also can use graphite materials. As a tool for EDM, the graphite material of electrode must have the following conditions:

　　(1) the structure is compact and the tissue is homogeneous; there should be no coarse particles and large pores;

　　(2) with high mechanical strength and good processability, it can work out complex shapes or sharp angles and flakes;

　　(3) the graphite tool electrode has a certain loss in the process of EDM, and this loss should be as low as possible;

　　(4) the discharge characteristics are stable and the processing speed is faster. Therefore, graphite with fine grain structure or graphite with fine particle structure is generally used in EDM, and the physical properties of graphite are best isotropic. Therefore, the graphite material with fine grain structure is the most popular graphite material used in China's electrical discharge machining.

　　In 2005, the domestic needs of EDM graphite is estimated to be 4000T, of which about 25% of high-grade graphite is used, and about 75% of middle and low-grade graphite is used. It is likely to rise by an annual increase of 10%. The use of imported high-grade graphite (mainly isostatic molding of isotropic graphite), accounting for about 10% of the total amount. There are many kinds of isotropic graphite for EDM abroad. They can be used in rough, semi finish, finish machining, fine machining, super fine machining and precision machining (line cutting, etc.).