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Analysis of future market prospect of super-hard tool materials
With the development of the material industry and precision machinery industry, the use of precision cutting, ultra-precision cutting and hard cutting materials is increasing, and the application of super-hard tool materials is becoming more and more extensive. Superhard material tool has high efficiency, long service life and processing quality is good wait for a characteristic, the past is mainly used in finish machining, in recent years due to improved the production technology of artificial superhard cutting tool material, control the purity of raw materials and grain size, the composite materials and hot-pressing process, such as application scope expands unceasingly, in addition to suitable for finishing and semi-finishing, can also be used for rough machining, is internationally recognized as the contemporary one of the most promising tool to improve productivity. Use of superhard material machining steel, cast iron, non-ferrous metal and its alloy parts, such as the cutting speed is high an order of magnitude of hard, tool life than high dozens or even hundreds of hard. At the same time, it appears, still make concept changes the traditional process, often use of superhard cutting tools can be directly to the car, milling, grinding or polishing, the hardened parts processing, can be used instead of a single process multi-channel working procedure, shorten the process.
Super hard cutting tool material refers to synthetic diamond and CBN (cubic boron nitride) of natural diamond and hardness and properties. Since natural diamond is relatively expensive, most of the production is made of artificial polycrystalline diamond (PCD), polycrystalline cubic boron nitride (PCBN), and their composite materials.
In the 1950s, the United States made use of artificial diamond micropowder and artificial CBN micropowder in high temperature, high pressure, catalyst and binding agent to form a large size polymer block as tool material. After that, South Africa's DeBeers, the former Soviet union and Japan also succeeded. Launched in early 70 diamond or CBN and carbide composite films, are they on the carbide substrate sintering or suppress a 0.5 mm ~ 1 mm layer of PCD and PCBN, low flexural strength so as to solve the superhard cutting tool materials, such as welding on difficult problems, to make the application of superhard cutting tool into the practical phase. Today again synthetic large single crystal diamond, as well as to design the grading form by using CVD (chemical vapor deposition) diamond film coating and functional materials such as diamond thick film, greatly broaden the application field of superhard cutting tool materials.
The research and application of superhard cutting tool materials in China started in the 70 s, and in 1970 built the first in guiyang superhard materials and products professional manufacturer, our 6, 1988 rich Nike founder of superhard materials co., LTD successful synthesis of the first high grade of cubic boron nitride abrasive. From 1970 to 1990, the annual production of super-hard materials increased from 460,000 carats to 35 million carats. Before and after the 90 s many superhard materials production plants introduced from abroad set of superhard materials synthesis equipment and technology, the production has been developed rapidly, to 1997 synthetic diamond in China has an annual capacity of 500 million carat left and right sides, CBN annual output of 8 million carats, ranks the first of superhard materials production country in the world.
Diamond has extremely high hardness and wear resistance, its microhardness can reach 10000HV, it is the hardest material in tool material. At the same time, its friction coefficient is small, and non-ferrous metal has no affinity, the chip is easy to flow out, the thermal conductivity is high, the cutting is not easy to produce the debris tumor, the processing surface quality is good. Can effectively processing non-ferrous metal materials and nonmetal materials, such as copper, aluminum and other non-ferrous metals and their alloys, ceramics, the sintering of hard alloy, various kinds of fiber and particle reinforced composite materials, plastics, rubber, graphite, glass and all kinds of wear-resistant wood (especially the composite materials such as solid wood and veneer).
The defects of diamond are toughness and low thermal stability. 700 ℃ ~ 800 ℃ when the carbide easily, therefore not suitable for processing steel materials. Because iron atoms are easy to work with carbon atoms at high temperatures, they are converted into graphite structures. In addition, using it to cut nickel-base alloy, it also quickly wears away.
Hardness is second only to diamond CBN (up to 8000 hv to 9000 hv), thermal stability and high (1250 ℃ ~ 1350 ℃), large chemical inertness of iron group elements, bonding resistance is strong, and with diamond grinding wheel grinding, edge is suitable for machining of hardened steel, thermal spraying materials, chilled cast iron, and 35 HRC more difficult cutting material such as cobalt and nickel based.
Super hard cutting tool material is an advanced tool material which has a broad application prospect in production. Artificial super hard cutting tool material, currently single crystal to coarse grain, high strength, multi-functional development. GE is now able to produce 6 carats of artificial diamonds (about 10mm), with a maximum size of 11.14 carats. The PCD is developed in the direction of large diameter, fine particle size, high impact resistance and high thermal stability.
The maximum diameter of PCD can reach 74mm and then cut into any shape with laser. The product size of PCD particles is 2 ~ 25 mu m; The finer the particles, the better the quality of the cutting edge. The larger the granules, the longer the tool life. DeBeers produces PCBN products with a maximum diameter of 101.6mm, which can process 70HRC high hardness materials. In addition, according to the patent, the UK has developed a PCD and PCBN by CVD method on the blade surface deposition layer of nickel, copper, titanium, cobalt, chromium, a mixture of tantalum, and titanium nitride or protective coating of titanium carbide, its high wear resistance than ordinary PCD and PCBN inserts 4 times.
CVD diamond film and thick film are the newly developed functional materials in recent years. Although the production has not yet formed scale, it has a wide use because of its excellent performance.
Natural and synthetic monocrystalline diamond and PCD and TFD exists between overlapping applications, they can complement each other to some extent, must according to the different specific situation, especially the price performance ratio to choose. In the new century, superhard tool materials CBN and diamond are expected to be used more and may be found to produce a new variety of tool materials with superior performance. According to the company, they have developed a new type of CBN super hard cutter, which has the advantages of both ceramic and CBN materials, and is the ideal material for high speed machining of hard and resistant cast iron. It is expected that in the future, with the increase of the application of new types of difficult cutting materials, the development and application of ultra-hard tool materials will be promoted.
The mechanism of hard alloy wire drawing die easy
Damage and wear mechanism of hard alloy drawing die: Breakage of hard alloy drawing die The failure of hard alloy wire drawing die can usually be found in the following types of damage: longitudinal, transverse, decarbonation, running number, normal wear, and the analysis of several causes of breakage is as follows:
Longitudinal crack: cemented carbide mold core cylindrical unprocessed, die set of inner hole machining quality is poor, bore a cone-shaped, trapezoidal, interference is not enough, the geometric angles is unreasonable, the compression amount is too large, carbide defects or improper selection of material tensile strength is not enough.
Transverse crack: the outer hole of hard alloy is not finished, the inner hole of the die sleeve is poor in quality, in a stairway shape, with the infilling of the top and bottom of the die, the defect of the hard alloy, the wrong number of the plate, the tensile strength of the material. Running no. : hard alloy material is not wear-resisting, the lubrication is not good when stretching;
Remove core: the set is almost infilled, the material quality of die is poor; In summary, the reasons of hard alloy material (quality defect, brand selection), mould processing, manufacturing reason and mould cover material are summarized. In terms of the status quo, improve the quality of hard alloy material wire drawing die, including reasonable brand choice, material design, ensure high wear resistance, high intensity of harmonious and unified, the reasonable groove design (lubrication, workspace, positioning, exit Angle, size design) is the key to improve the overall level of the drawing die.
Problem of wear mechanism of hard alloy wire drawing die Stretching high carbon steel, especially the high carbon steel, spring steel, hard steel, alloy steel with high viscosity, such as, current WC/Co in cemented carbide is often characterized by wear resistance and tensile strength is not enough, life is not very ideal.
When such materials are stretched, the interface is adhesive and diffused. Because at the interface between this kind of material tensile material spreading hard alloy of Fe, but due to the high carbon of stretch material diffusion rate of Fe is weak, and the diffusion in the alloy Co to stretch in the material due to high carbon material was unusually strong. The intense diffusion of cobalt causes the alloy to wear out rapidly, thus reducing the adhesion of WC/Co on the surface of hard alloy surface, and the loose WC is rapidly grinding and peeling away. In the absence of cooling, the wear tends to accelerate due to thermal fatigue.
In view of the cemented carbide drawing material abrasion is mainly due to the spread of the cobalt consumption when stretching high carbon material, reduces the WC/Co binder, so stop the Co diffusion or solve this kind of material wear and prolong the service life of the key.