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.

　　According to different application of carbon and graphite product, diiferent physical-chemical standard indicators were stipulated to evaluate quality. Physical-chemical indicators of product is concerned not only with that of raw material, but also with manufacturing technology.There are some rules existing between raw material and manufacturing technology. If we want to keep product be qualified, we should ensure raw material is qualified, manufacturing technology is responsible. This article focus on introducing main physical-chemical indicators. There are six main indicators.

　　1. True density

　　True density means the weight of per unit volume of material excluding proportion,who is measured by g/cm³.Usually，we smash assay into 0.15mm, infiltrate assay with alcohol or distilled water, and weight the handled material via comparison weighing method.

　　By testing true density, we can acquaint basic particle degree and arrange degree of material. As for graphite product and natural graphite sample, true density can reflect the degree of graphite lattice structure.

　　2. Apparent density

　　Apparent density means the weight of per unit volume of material including porosity, which is measured by g/cm³ too.

　　3. Ash content

　　Most ash contained in Carbon material is Oxidized metal and nonmetal element. Among all kinds of ash, metallurgical coke content(12%-16%) is the highest, the second one is anthracite(7%-12%). Ash of pitch coke and petroleum coke is around 0.5%. The main compound in ash is ferric oxide, aluminum oxide and silicon dioxide, which account for over 80% of the total ash content.

　　4. Mechanical strength

　　In carbon and graphite products industry, we are often used to denote the mechanical strength by three indictors: compressive strength, tensile strength and bending strength. The relationship of these three indictors are as follows: compressive strength of graphite product is as twice larger as bending strength. And bending strength is as twice larger as tensile strength.

　　5. Specific resistance

　　Most carbon and graphite product appllied to electric conduction, so better the electrical property is, better the material is. That is the date of specific resistance should be as low as possible, lower speific resitance means higher current density.

　　If you want to learn more knowlegement about graphite and carbon product, welcome to our website:www.bjgreatwall.com

　　Summary of graphite materials ore resource，Graphite is one of the carbon crystal mineral, lubricity, chemical stability, high temperature resistant, the thermal conductivity of the conductive, special and plasticity, coating and other excellent properties, its application field is very wide.The graphite in the metallurgical industry is mainly used as refractory materials;Used for mould in the casting industry and antirust coating;In the electrical industry for the production of carbon electrode, electrode carbon rods, batteries, made of graphite can be used as a television tube coating, made of carbon products can be used for generators, motors, communications equipment and so on many aspects;In the mechanical industry used as aircraft, ships, trains, and other high-speed operation of the machinery lubricants;In the chemical industry used in the manufacture of various corrosion vessels and equipment;Used in the nuclear industry in the atomic reactor neutron moderator and protective material, etc.;In the aerospace industry to do the rockets the engine tail nozzle throat lining, rocket, missile of insulation, heat resistant materials and satellite radio connection signal and the conductive structure material.In addition, graphite or light polishing agent and anti-rust agent, glass and paper in pencil, ink, black paint, printing ink and the raw material of synthetic diamond.With the development of modern science and technology and industry, the application field of graphite continues to widen, has become an important raw material in the field of high-tech new compound material, plays an important role in the national economy.

　　High pure graphite is widely used in casting, metallurgy, mold and other industries, high precision CNC machining equipment for production of horizontal continuous casting with high purity, high strength, high density graphite crystallizer and the electronics industry with a graphite mold; metallurgical industry graphite mold and other various shapes, various uses ink stone processing of finished parts to realize, the needs of machining precision and roughness of graphite.

　　High purity graphite material has outstanding features.

　　1. Thermal stability: the reliability of the product quality is guaranteed by the special design of the conditions for the rapid quenching of the graphite crucible..

　　2. Erosion resistance: matrix design fine uniform delay crucible erosion degree. Impact resistance: graphite crucible can withstand the high thermal shock intensity, so any process can be assured to.

　　3. acid resistance: the addition of special materials significantly improve the quality of the crucible, in the acid resistance of the outstanding indicators, and greatly extended the life of the graphite crucible.

　　4. high thermal conductivity: high content of fixed carbon ensure good thermal conductivity, shorten dissolution time, and significantly reduce the energy consumption.

　　5. metal pollution control: the strict control of the material composition, guarantee the dissolution of the graphite crucible no pollution to the metal.

　　6. the quality stability: the production technology and the quality guarantee system of the high pressure forming process guarantee the stability of the quality.