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Introduction After more than 40 years of development, China's super-hard materials industry has made tremendous progress, achieved rapid development, continuous technological advancement, and expanding application fields. Not only has it been widely used in various aspects of national economic basic industries such as building materials and construction. And more and more widely used in petroleum, coal, automotive, electronics, machinery manufacturing and other national pillar industries. According to statistics, the scale of China's superhard materials industry has exceeded 30 billion yuan. With the rise of the global low-carbon economy, the development of emerging industries such as photovoltaic power generation, LED, IT, and aerospace military is on the rise. Superhard materials will play an irreplaceable role in the grinding, polishing and cutting functions of these emerging industries. It is said that the development of emerging industries will in turn drive the development of super-hard materials to a wider and more sophisticated application field. The future development of super-hard materials is very broad.
With the deployment and promotion of national energy conservation and emission reduction policies, higher requirements have been put forward for energy conservation and emission reduction in all walks of life. The realization of energy-saving and emission reduction in the super-hard materials industry is not only the trend of the times, but also promising and promising.
1. Super-hard materials products industry energy-saving emission reduction internal and external environment 1.1 Policy background In the context of the country's better to reduce the rate of GDP growth, but also to strongly promote the transformation of economic structure and economic growth mode, energy-saving emission reduction has become the general trend. Any high-energy, high-emission production methods and processing methods will be limited. In line with policy guidance, actively carrying out technological innovation, promoting energy conservation and emission reduction is the only way and the only direction for every enterprise, and the super-hard materials industry is no exception.
1.2 Analysis of the status quo of energy saving and emission reduction in the industry production At this stage, China's superhard material products have two main characteristics in the manufacturing process: (1) the formulation of the coarser elemental element powder as the main component; (2) the cutter head The hot pressing sintering characterized by low voltage and large current in the sintering process is the main sintering means.
The formulation system with the coarse elemental element powder as the main component has obvious advantages in formula adjustment flexibility and is easy to form, but the particle size and distribution, morphology, phase and crystal structure, purity of different elemental element powders, Factors such as oxygen content and specific surface area directly affect the physical and chemical properties of the final carcass material, which are affected by the batch and storage of the manufacturer's products. Moreover, when the target carcass material is prepared by using elemental element powder, the multi-component element powder needs to be fully alloyed by thermal diffusion, and the process requires sufficient temperature and sufficient time to complete the process, although the diamond has a certain high temperature resistance, Thermal damage is still a major problem affecting the quality of diamond products. Therefore, products using elemental element powder as the main component often exhibit common problems of poor quality stability and low quality, and can only be sold at very low prices, resulting in consumption of a large amount of raw materials and energy, and only a meager profit. It causes a lot of waste of resources and generates a lot of waste.
The largest direct energy consumption in the manufacture of superhard materials comes from the sintering process, accounting for more than 70% of the energy consumption of superhard materials. The most common sintering method is hot pressing sintering characterized by low voltage and large current. The hot stamping frame in this sintering mode is still based on low-cost cast iron material, which generates eddy currents under electric field and generates heat, which wastes power and It is easy to cause the frame to be deformed and scrapped; the heat insulating material is mainly cement asbestos board or mica sheet, which has poor heat insulation effect and durability, resulting in serious heat loss and deformation of the mold frame; graphite electrode and abrasive tool are easy to be oxidized and damaged and consumed. Large, leading to the demand for graphite materials, waste, graphite materials production and harmless treatment consume a lot of energy, therefore, the sintering process is another key to energy-saving emission reduction in the manufacturing process of super-hard materials Link.
1.3 Analysis of the status quo of industrial applications The emergence of diamond tools is a revolution in the history of human tools, greatly reducing the labor intensity of hard and brittle materials processing. Energy consumption, dust, waste, and greatly improved processing efficiency, has been widely used in construction materials, construction, oil, coal, automotive, electronics, machinery manufacturing and other industries. For example, diamond wire saws are used in mining, compared with traditional â€œblasting + flame cuttingâ€ mining: 1 mining is more applicable. Wire saws are suitable for all types of mines, while flame cutting is only available for granite mines with high quartz content and low cracks. 2 mining efficiency is higher. The mining depth can reach 10-20 meters or even deeper, and the flame cutting is generally within ten meters; the mining speed can reach 3-4 m2/h, which is 2-3 times that of flame cutting. 3 high rate of finished products, low overall cost. The sawing of the wire saw is only about 11mm, and it will not be wasted as a waste of resources. The flame cutting surface is rough and uneven, and the kerf is 100-300mm, which causes a great waste of resources. 4 Safety and environmental protection, wire saw mining without noise and dust, does not affect the environment, workers have low labor intensity and high safety.
Diamond wire saws have also been used more and more widely in the field of building construction. Compared with the blasting method or mechanical chiseling method, the wire saw cutting method is a static cutting method. It has no vibration and no damage to the parts to be retained, and the operation safety is high. It is the demolition of the super-large reinforced concrete construction, and the wire saw cutting method has unparalleled advantages. Typical application examples are shown in Table 1.
Since the 1990s, in order to solve the problem of cutting large-size silicon rods, wire saw processing technology has been used to cut silicon rods into thin sheets. Currently, it is undergoing processing with bare metal wires and free abrasives to electroplated consolidated diamond wire saws. The process of processing transformation. It has been reported that the consolidated diamond wire saw can produce expensive single crystal silicon or polycrystalline silicon material because it does not use free abrasive, and the slit is only 0.01-0.015 larger than the saw wire. At the same time, the production efficiency is greatly improved and the power consumption is significantly reduced.
In summary, the emergence of super-hard materials and products has greatly improved the processing efficiency in the field of hard and brittle materials processing, reduced the labor intensity, and achieved energy saving and emission reduction during the processing. With the rapid development of China's emerging industries, it will certainly expand the broader space for the development of super-hard materials and products. The super-hard materials and products industry will also develop into a strategic emerging industry in China.
Throughout the current situation of China's superhard materials and products application, there will still be much room for improvement in energy conservation and emission reduction, which is reflected in the following aspects:
(1) Superhard material products should replace the ordinary abrasive products as much as possible. The grinding efficiency of superhard materials is much greater than that of ordinary abrasives. Superhard material products can replace ordinary abrasive products, which can greatly promote the efficient processing and application of the current general abrasive products industry. Energy conservation. In the aspect of bearing grinding, the use of cubic boron nitride ceramic grinding wheel instead of silicon carbide ceramic grinding wheel can improve the efficiency; in the aspect of architectural ceramic polishing, the development of diamond grinding block replaces the traditional silicon carbide grinding block, the grinding efficiency can be increased by 30-40%. The power consumption can be reduced by 40% and the emission can be reduced to 1%.
(2) The quality of dry processing tools is developing slowly. At this stage, most of the working process of super-hard materials requires cooling of the coolant. The reason is that the performance of the product can only achieve good processing results under cooling conditions. For some long and short materials, a large amount of coolant is often inhaled and contaminated or deteriorated, resulting in great waste.
(3) The overall size of the working part of the drilling and cutting tool is too large, resulting in wide processing slit, large power consumption, low processing efficiency, waste of valuable materials, large processing defects and high energy consumption. For example, in the high-grade marble and single crystal silicon cutting process, because the working part of the diamond tool is thicker, not only the material consumption is large, but also the processing quality is degraded, the processing speed is slowed down, and the power consumption during the processing is relatively increased.
(4) The product's sharpness and insufficient stability result in low processing efficiency, poor processing quality, high waste, and large power consumption, resulting in waste of resources, energy, manpower and time. For example, the maintenance and reconstruction of highways and bridges requires the construction period to be as short as possible and must be completed on time, but often due to insufficient or unstable diamond tools, the construction schedule is affected, construction time is extended, and human and power resources are wasted. , causing great losses and waste.
It can be seen from the perspective of the application of super-hard materials, not only the existing products still have a lot of room for improvement in energy saving and emission reduction, but also there is still much room for expansion in energy conservation and emission reduction in the application field.
2. Super-hard material products manufacturing process has great potential for energy saving and emission reduction. By optimizing formula design and developing new sintering technology and equipment, it can greatly reduce the resource power consumption in the production process and achieve energy saving and emission reduction.
2.1 Optimize formula design and realize energy-saving and emission-reducing formula design is the basis for determining product performance, including the proportion of various raw materials, the chemical and physical properties of each raw material, and the way of introducing elements. In the formulation design process, the direct cost concept has more influence on the formulator to turn more attention to raw materials (such as reduced iron powder) that are less expensive but have poorer quality stability. Such raw materials tend to have coarser particle size and high oxygen content, which leads to difficulty in sintering of the product (high sintering temperature), low performance and high volatility, which means that a large amount of social resources such as raw materials, electricity, labor, etc. are wasted, and at the same time, it affects the application field. Energy conservation. The use of ultra-fine, low-oxygen element powder instead of coarse-grained elemental powder or ultra-fine pre-alloyed powder in the formulation can not only reduce the sintering temperature, but also significantly improve the product performance, that is, achieve energy-saving emission reduction during the production process. Moreover, the energy saving and emission reduction of the application side is realized, and the comprehensive benefits are remarkable. Table 2 shows the comparative economic analysis of Benlong's use of carbonyl iron powder instead of electrolytic iron powder for a diamond grinding wheel.
Guo Hehui pointed out in the literature that if China produces and sells billions of yuan of diamond tools, it will consume about 100,000 tons of steel and non-ferrous metals, 400 million diamonds, 600 million kilowatts, 110,000 tons of packaging materials and 52,000 tons of grinding wheels. , paint 0.35 million tons, if all the production of "excellent" diamond saw blades, in the case of ensuring the same sales income, at least 50% of resources can be saved (steel, non-ferrous metals 50,000 tons, diamonds 200 million grams, electricity 3 Billion degrees, 55,000 tons of packaging materials, 26,000 tons of grinding wheels, and 0.175 million tons of paint. It can be seen that the optimized formula design has great potential in saving resources, saving energy and reducing emissions.
2.2 The development of new sintering technology and equipment, energy saving and emission reduction sintering is the key to determine product performance, and is the most energy-consuming part of the super-hard material manufacturing process, so it is the key link of energy saving and emission reduction.
At present, the sintering method dominated by the super-hard material products industry is a resistance hot-pressing sintering process, which has the characteristics of adapting to small batch production, flexible process adjustment, and wide range of sintering temperature, but the disadvantages of low heat utilization rate are also prominent, and preliminary estimates are over 70%. The heat is wasted. The development and application of new mold materials can effectively reduce the heat loss during hot pressing and sintering; the development of application of hot isostatic pressing method and pressureless sintering method can significantly reduce the sintering energy consumption, and the product quality stability is better. Achieve energy saving and emission reduction in the sintering process.
2.2.1 New hot-pressing mold material By adopting new mold materials and improving the heat preservation effect, the number of the traditional hot-pressing sintering process can be effectively reduced. According to the statistics of the first half of 2010, the use of the new hot-pressed mold materials reduced the electricity consumption per 10,000 yuan of output by 14% and saved electricity by 1.4 million kwâ€¢h in half a year.
2.2.2 Hot isostatic pressing method Hot isostatic pressing (HIP) is the lowest sintering technology for diamond tools in the world today, combining the technical advantages of hot press sintering and pressureless sintering. The utility model relates to a technology for pressing, sintering and densifying a product by using an inert gas such as nitrogen or argon as a pressure transmitting medium, usually under the action of pressure of 900-1100 Â° C and 50-200 MPa. At present, due to the high technical difficulty and large investment, the one-time investment in purchasing a hot isostatic pressing equipment exceeds 10 million yuan, and the maintenance cost is high and the running cost is high. Therefore, only a very small number of technical capital is abundant in the world. Diamond tool companies can fully master HIP technology. The successful practice in foreign countries shows that the use of hot isostatic pressing technology instead of the traditional hot pressing sintering technology greatly improves the production efficiency, greatly reduces the energy consumption and mold loss, reduces the product air raid and high density, and can comprehensively improve the working efficiency of diamond tools. And working life. Table 3 compares the energy consumption of hot press sintering and isostatic pressing on a certain product.
2.2.3 High-temperature pressureless sintering technology The research of foreign powder metallurgy sintering technology found that the high-temperature pressureless sintering process is an advanced technology more suitable for scale production for those products with liquid phase in the sintering process, in the United States, Japan, Industrialized countries such as Germany have been widely adopted. This process combines the technical advantages of pressureless sintering and high-temperature sintering, and increases the sintering temperature to above 900 Â°C in a pressureless state. The carcass material has excellent physical and chemical properties. The high-temperature pressureless sintering technology is used as the preparation process of the diamond product carcass material, and has the advantages of the following aspects compared with the conventional hot-press sintering method.
(1) The shape of the product can be solved, as long as the compact can be cold-formed, and the sintering densification effect can be achieved by high-temperature sintering, and the shape of the sintered blank can be ensured because the entire process is completed in a uniform temperature field. And dimensional accuracy, to minimize the grinding allowance after sintering.
(2) Pressureless sintering has the characteristics of large output, almost no mold loss, low energy consumption and stable product quality, and is suitable for large-scale production.
The company's implementation of the traditional hot press sintering method and high temperature pressureless sintering method to produce a certain diamond cutter head is shown in Table 4.
3 Super-hard materials products application areas of energy saving and emission reduction prospects Super- hard materials products through technological transformation and continuous expansion of their application areas (especially to replace ordinary abrasives) to achieve energy-saving emission reduction prospects in the application field, space is huge, in recent years In the construction ceramics processing method to achieve energy saving and emission reduction has achieved great results, the following aspects:
3.1 Metal bond diamond grinding block instead of diamond bituminous silicon carbide grinding block has been applied in batches and has a rapid growth trend. The bituminous silicon carbide grinding block has been widely used in the grinding and polishing of architectural ceramic surfaces since the 1980s. It has the characteristics of high polishing efficiency and wide adaptability. However, the bituminous soil combined with silicon carbide grinding block has a short service life, the average service life is only 1 to 3 hours, the weight of each grinding block is about 1.1 kg, the SiC abrasive containing 235 g, the chloromagnesium cement 850 g, the plastic card holder. 20 grams, in which the magnesium chloride cement and silicon carbide abrasives are turned into waste residue after grinding, accompanied by a large amount of wastewater, and the generated wastewater is weakly alkaline. According to statistics, China consumes 1.8 million pieces a day, equivalent to 423 tons of silicon carbide, 1530 tons of magnesium oxide, 36 tons of plastic, and 100 tons of packaging paper. It also means that 2,000 tons of waste and a large amount of alkaline waste water are produced every day, and it needs to exceed every day. 2000 tons of transportation. The extensive use of silicon carbide grinding blocks has caused excessive exploitation and consumption of natural resources. The production and use of silicon carbide grinding blocks have caused considerable damage to the environment. At present, magnesium oxide has been listed as a non-renewable strategic material controlled by the state as a natural resource. Silicon carbide as a high energy consumption and high pollutant resource has also been restricted by the state. Therefore, the development and application of metal bond diamond grinding blocks have energy saving and emission reduction. Significance.
During the grinding and polishing process, the average life of the diamond grinding block is increased by more than 100 times, the grinding efficiency is increased by 20%, and the consumption cost, power consumption and emission pollutants are respectively 75%, 60% and 1% of the ordinary grinding blocks (Fig. 1). .
3.2 Diamond dry grinding wheel The four sides of the glazed tile (commonly known as "ceramic piece") used for interior wall decoration often need to be ground by grinding wheel to obtain more accurate size. The conventional edging wheel needs water cooling when grinding. Since the water absorption rate of the glazed brick is generally about 20%, the glazed brick absorbs a large amount of water while cooling, which easily causes the package to be damp and the glazed brick is dyed and mildewed. Therefore, it is necessary to The glazed tiles after water absorption are dried, and a special drying kiln is built, which consumes a lot of energy. Through the development of diamond dry grinding wheel, waterless cooling grinding can be achieved, which can save the brick drying process and save space and energy consumption. The comparison of the batch usage of Shanghai Smick shows that the use of dry grinding wheel grinding edge can save 0.3 cubic meters of natural gas per square meter of glazed tiles, and the overall processing cost can save 0.56 yuan per square meter. If the national annual output of glazed tiles is 1.3 billion square meters, it can save 390 million cubic meters of natural gas per year (or equivalent to other energy sources), saving 728 million yuan.
3.3 Ultra-thin ceramic cutting blades The thickness of diamond ultra-thin saw blades for ceramic cutting is generally less than 1.4. It is used for cutting, mosaic and slotting of architectural ceramics, compared with ordinary cutting diamond saw blades (1.2mm) The thickness of the ultra-thin sheet and the ordinary sheet of 2.0 mm thickness as an example) have the following advantages:
(1) Low energy consumption. During the cutting process, the current of the ultra-thin sheet is reduced by more than 45% compared with the conventional cutting saw blade.
(2) Less dust emissions. Due to the thinning of the cutter head, the removal of the processed object during the cutting process is significantly reduced, and the dust emission is reduced by 37%.
(3) Increased efficiency. Due to the thinning of the saw blade, the material removal amount and cutting force in the cutting process are reduced, the cutting speed can be greatly improved, and the processing efficiency is significantly increased.
(4) Low noise. Due to the thinning of the saw blade, the cutting force during the cutting process is reduced, and the vibration generated by the friction between the saw blade and the processed object is reduced, and the noise is significantly reduced.
4. Prospects and Suggestions The emergence of diamond tools is a revolution in the history of human tools. It not only greatly reduces people's labor intensity, but also improves work efficiency. It has become a "tool" for energy conservation and emission reduction, and will save energy in more fields. The platoon plays an irreplaceable role. The super-hard materials industry will surely become one of the indispensable basic industries for energy conservation and emission reduction, with broad development prospects and a bright future.
In the design and manufacture of super-hard materials, with the development and application of new materials, new technologies, new processes and new designs, energy-saving and emission reduction also have a lot to offer. In order to guide enterprises to better carry out energy conservation and emission reduction work, it is recommended that associations and enterprises strengthen the following two aspects of work.
(1) The Association establishes an energy consumption evaluation index of 10,000 yuan of output value (sales value) of representative products of different categories, evaluates the development trend of the industry in energy conservation and emission reduction, and promotes energy conservation and emission reduction of enterprises.
(2) The company should establish an evaluation and evaluation system for energy conservation and emission reduction, such as the output value of the output value of 10,000 yuan (sales value), the consumption value of the output value of 10,000 yuan (the sales value), the energy consumption index of the combined agent, and the output value of the product (sales value). Standards, etc., through internal assessment incentives, guide enterprises to independently carry out energy conservation and emission reduction work.
 Jiang Rongchao, et al. The latest application and progress of foreign superhard material tools (below). Superhard Materials Engineering, 2008, 20 (5): 42-48
 Zhou Rui, et al. Research status and progress of diamond wire saw, Modern Manufacturing Engineering, 2004 (6): 112-114
 Guo Hehui. Energy saving and emission reduction is the only way for diamond tool manufacturing industry. Abrasives Communication, 2007(12):23-25
About the author: Yin Yuhang, male, born in 1962, Ph.D., senior engineer, presided over more than ten national and provincial projects, applied for more than 20 invention patents and utility model patents, and published several academic papers.
Grating Floor,Industrial Steel Grating,Heavy Duty Steel Grating
Steel Grating,Miscellaneous Co., Ltd. , http://www.steel-grating-manufacturer.com