Aluminum oxide ( corundum ) used in the coated abrasive and abrasive has a long history , but also a great number of international annual use , the alumina raw material of tungsten carbide and nitride materials in terms of the cheapest , while alumina tool high prices . Carbide cutting tool about the proportion of alumina ( tungsten carbide base ) of the third volume prices , aluminum carbide cutting tool cheaper than this is one of the factors prompting the international aluminum tool development. The aluminum oxide ( alumina ) ceramic tool is its development of products, fine tip , is a model of modern alumina ceramic , high added value . Al2O3 ( alumina ) powder 4 to 5 yuan / kg, while the price of alumina-based tool from 2000 to 3000 yuan / kg. 2007 sales in Western countries ceramic tools is estimated at over 45 billion U.S. dollars, accounting for about half of the alumina-based ceramic tool . Among the largest output in Japan , followed by the United States , Germany, Britain , etc., while Russia also has a certain production scale . But domestic resources for this material widely , inexpensive , capable of producing high value-added development tools but little could enrich China tungsten resources with emphasis on tungsten carbide cutting tools related. First, the performance of alumina [PAGE] Modern new ceramic material comprises oxides, carbides , nitrides , borides , silicides, and complex compounds between them. There are works from the use of structural ceramics , functional ceramics , tools and ceramics. Ceramic knives are used to turning or milling metal and alloy tool. Except for the carbide tool that is an oxide ceramic , a nitride . The oxide is the most suitable alumina ( corundum -α-Al2O3) material. Pure crystalline Al2O3 dozen exist at low temperatures , but are mainly three: the α-Al2O3, β-Al2O3, γ-Al2O3, all crystalline at temperatures over 1600 ℃ above , are converted into high-temperature stable α- Al2O3 ( corundum ) , this change is irreversible . Al2O3 is very low hardness in general , only the α-Al2O3 corundum hardness ( Mohs hardness 9 ) is very high, to make the cutting tool and corundum wear parts . α-Al2O3 is hexagonal , corundum ( unit cell is sharp rhombohedral ) structure , a = 4.76Å, c = 12.99Å. Density 3.96 ~ 4.01g/cm3, hardness (HV) 3000kg/mm2, Young's modulus 42kg/mm2, thermal conductivity 0.07 cal / ( cm • sec • ℃), the thermal expansion coefficient of 8.5 × 10 ˉ 6 ℃. Chemical stability of the alumina is a strong reaction with a lot of material is very weak . Second, the current alumina ceramic cutting tool steel , cast iron, alloy steel and stainless steel and other commonly used carbide-based cemented carbide (WC-Co, WC-TiC-Co). For some special materials also used the highest hardness of diamond and cubic boron nitride (CBN), but their intensity lower than the carbide and diamond cutting tools are not conducive to the steel material , because diamond is easy carbonaceous elements and iron the reaction of iron carbide , leaving the diamond loss, but diamond tools for machining aluminum-silicon alloy has unique advantages. The CBN for many materials , such as iron-based not react to the processing of chilled cast iron, Stellite alloy , heat-resistant nickel-based alloys have better performance. [PAGE] Alumina and other characteristics are different tool materials : stable alumina chemical properties, particularly good oxidation resistance , even if it is in the cutting edge can be a long red hot cutting , the alumina ceramic tool is particularly suitable for high-speed cutting and heating cutting . Due to the poor wettability of alumina to metal in the majority , it is difficult to bond with a metal (e.g., steel and bonding temperature : aluminum oxide above 1528 ℃, tungsten carbide is 1316 ℃), the cutting performance of the friction coefficient low , low cutting forces , difficult to produce BUE and adhesive wear , so easy to get a high processing light cleansing . Alumina is the most of all the tool material inactive , when you can reduce the spread of the cutting tool wear , Al2O3 dissolution rate in iron than WC 4-5 times lower , thus alumina ceramic cutting tool wear when steel rate than WC -based cemented carbide cutting tools as small as a few times to magnitude . The use of high alumina ceramic cutting tool wear and suitable for high-speed cutting of large machinable features , such as the processing length 7320mm, muzzle diameter of 155mm, 310mm rear end of the barrel diameter steel . Most suitable for processing aluminum metal materials , especially for cutting chilled cast iron or hardened steel , materials used for these fine cars instead of grinding can achieve significant technical and economic benefits . Alumina at high temperatures to maintain a high hardness , cutting speed up to 1300 m / min. Alumina is currently mainly used for semi-finishing tool and precision machining , precision cutting its accuracy and finish suitable for hard materials to the car instead of grinding , and several times greater processing efficiency , processing costs can be reduced by more than half , so the tool is very popular with alumina people welcome. Many in the German car parts are alumina ceramic tool in turning instead of grinding finishing to complete . When cutting, ceramic tool can withstand high temperatures 2000 ℃ , and then at 800 ℃ carbide soften . Carbide cutting speed is too high at the time , the temperature of overheating , resulting in severe wear crescent tool damage. High temperature ceramic blade for cutting the high temperature more favorable , since the metal of the workpiece and the plastic tends to soften at high temperatures , and low-energy cutting . Low thermal conductivity of the ceramic high temperature only in the nose , the heat generated by the high-speed cutting with both chip away . Many researchers believe that: alumina ceramic inserts can , and must be 10 times higher than the carbide cutting speed for cutting down the line , in order to truly reflect the advantages of ceramic blades. [
First, the decline in factor analysis Last week decline in the first three categories of representative products, two low-voltage electrical electrical appliances, machinery and equipment in food processing machinery . Tapes current index 95.56 , up 2.65% decline . Following up on the stage , tape products prices fell again , sealed plastic , glass, plastic and other commonly used tape products prices fell slightly . Recent market conditions have improved, compared to the previous month lukewarm business, many businesses saw the opportunity to cut prices , but the price is relatively small ups and downs , I believe that within the next few weeks , the price will return to a steady state. Copper class period index 95.04 , or 2.33% , with larger decreases . But for the raw materials market, the more normal price fluctuations , supply shortage in the domestic situation , some copper manufacturers also export , so that the imbalance between domestic supply situation is further exacerbated by continued domestic copper demand for international high, pushed import prices is bound copper . In contrast , copper prices have continued to expand production capacity in the process of continuing to fall . Screen class period index 95.46 , down 6.82 percent . Spring Festival approaching, the device functions as a safeguard highway safety net during the Spring Festival , part of the municipal increase the care and maintenance of highways and other public places of safety equipment , increasing the demand for screen- class products , market traders reflect the recent cell- protective bar sales better. Frame rails, wire fence bilateral sales in general , the current prices of the product is mainly merchants temporary adjustment , the latter is expected to rebound . Two , or factor analysis Class II prices rose last week, the top three products for the hardware and tools on behalf of high voltage insulation class abrasive and coated abrasive class , electrical, electrical , and mechanical equipment food processing machinery and equipment categories. Tools, fixtures class period index 98.99 , up 0.54% , tools, fixtures prices less volatile . Relatively stable with a variety of machine tool sales , along with the popularity of CNC machine tools , mechanical clip-on tools popular with consumers , and the hand- sharpening knives have gradually surfaced out of the market trends , new materials, good quality and durable turning, cutters , boring tools , such as by new and old customers attention. From the brand perspective, a good amount of domestic brands , foreign Dirk, Ticketmaster and other sales. Lamps current index 102.27 , up 2.72% , the larger the rate of increase . With the implementation of energy conservation and other policies on the market incandescent significant reduction in LED light fixtures to seize the hardware market, will inevitably lead to a rise in the cost of lighting . Now it seems that the market volume as before incandescent LED lights , large factories, mines operating areas are still using incandescent power ; addition, the Spring Festival approaching, decorated with colored LED lights optimistic about sales , market traders make recommendations adequate supply ready . Abrasives and Abrasive class period index 111.19 , up 5.25% , prices rose sharply. Abrasives and Abrasive domestic market still is not busy , the shops in the market to sell abrasive showing inexpensive, low-end products , a single species and other factors. Combined November and December months , the abrasive industry prices start from the bottom , all the way back up, the impact lasted three weeks ago, but the view of the magnitude of increase is slowing , prices continue to rise showing fatigue trend.