Manufacturers supply coated sand, sand EPC with Sarah

Applications Ⅰ V- method for casting and lost foam casting V -???? Method of casting all with dry sand molding, casting most of them have disappeared dry sand molding. Such as the use of silica sand, sand off the process for distributing a lot of silicon dust, bad working conditions, which is a serious problem. Sarah instead of silica sand with sand, can significantly reduce the dissemination of dust, dust and silica dust contained little to improve working conditions and protect the environment is significant. In addition, there are the following benefits: 1. Sarah sand refractoriness higher than silica sand, high and tight shape when filled, therefore, can improve the surface quality of the casting, production scrap rates reduced; 2, spherical Sarah sand good liquidity, complex shape castings, internal angle, deep recesses, holes and other difficult to fill flat parts, are easy to fill tight. Thus, the package can significantly reduce defects in these parts of sand, greatly reduce the workload of cleaning and finishing; 3, sand casting consumption per ton can be reduced by 90 percent, waste emissions are correspondingly reduced; 4, EPC when using resin bonded sand molding, the amount of resin can be reduced by 1/3. Although the price is higher than the sand Baozhu sand lot, such as used properly, comprehensive accounting down, not only can significantly improve the quality of casting, but also reduce production costs. Baozhu sand low coefficient of thermal expansion is an important advantage to prevent casting defects produce expansion, but this feature also has some negative effects. After its expansion due to heat is much lower than that of silica sand, the production of iron castings, ductile iron castings especially when, casting graphite mold restrict the expansion of the role of the poor, and thus easy to produce shrink casting defects, should be properly set up the riser. Ⅱ alternative in investment casting sand zircon sand and zirconium powder? At present, Investment precision casting more than 500,000 tons of annual output, the shell is about 100 million tons of waste, recycling shell material is a an important issue of concern. High quality investment casting precision casting, shell surface layer refractories (including paint aggregates and sprinkle sand) were powered by zircon sand powder and zirconium sand. After casting shelling, it can not be separated and the back layer refractories, not only a waste of resources shortage, the high cost of zircon sand, but also increases the difficulty of the shell waste recycling. From the end of 1996, Japan will increase investment casting technology, the development of shell surface with artificial material, as one of the strategic basis for technology research and development projects, by the Japan Foundry Association Management, Hitachi Metals, ヨ Neko inter- ア ド ki ャ su Suites, Daikin gu pa - tsu , ki ャ su Te Rousseau, wonderful casting in mining and other well-known enterprises, as well as ceramics Itochu joint implementation, the subjects completed in November 2009. The primary outcome was replaced with a sintered ceramic zircon sand, zircon sand with a ceramic powder instead of flour, the backing layer is still used with ceramic components similar to silicon alumina refractories. ? This shell can be used for atmospheric and vacuum casting foundry, it has to be made of nickel-based alloy turbine nozzle ring. To ensure the surface coating of aggregate filling performance, the surface coating of ceramic powder to be used in surface seizure treatment. Approach is: the powder by high temperature flame to seizure edges, smooth surface. Since the shell is used in refractories all silicon aluminum material, abandoned shell, all ceramics recovered from Itochu Corporation, after appropriate treatment, re-made ceramic and ceramic powder, recycling, saving zircon sand, but also to protect the resource. Our Baozhu sand, is obtained after fused, dense texture, smooth surface, superior to sintered ceramic. Special mention should be made: the manufacture Baozhu sand, because the blowing action, 270 mesh particles (diameter 0.053㎜ less) may be about 5%. These particles remain in Baozhu sand is inappropriate. If it is to collect, for the preparation of surface coating, powder filling performance was better than some surface-melting process. Therefore, it is said: At present, the investment casting industry to avoid using zircon sand conditions are ripe. Ⅲ in the production of large steel castings of alternative chromite sand? Baozhu sand, in addition to the bulk density of less than chromite sand, some of the major thermal properties such as thermal conductivity, thermal expansion coefficient, refractoriness, etc., and chromite sand close. In particle shape and resistance to crushing is concerned, much better than the chromite sand, while the price is only about 1/2 of chromite sand. On the basis of comprehensive analysis, not difficult to see Sarah sand chromite sand is an ideal alternative materials. Japanese Special Steel has been used in the production of sintered ceramic instead of chromite sand, well, deficiency is easy to produce sticky sand casting surface defects. Through experimental research, the resulting solution was added 4 percent of spherical iron oxide. Baozhu sand surface conditions far superior to sintered ceramic, casting should not easy to produce sticky sand defects. In fact, China has several steel plant alternative chromite sand sand with Sarah, have been very good results. Sarah replaced with sand chromite sand, both to improve the surface quality of the casting, but also reduce production costs, but also facilitate the regeneration of old sand, and reuse. Ⅳ instead of silica sand in resin-bonded sand and green sand in the sand, core sand with sand using part Sarah, can effectively prevent the generation expansion casting defects. In recent years, some Chinese manufacturers of coated sand, the raw material has been added to part with sand Baozhu sand, which can make the shell made of shell core with high temperatures, low inflation, easy to collapsing, high strength, low gas evolution performance. For particularly complex shape of the core, can also solve difficult shooting sand compaction problems. In order to meet the requirements of lightweight, thin-walled cast iron production, such as the part surface sand with a low density ceramic, can effectively solve the water shortage and the cold compartment of the type of problems, but also to avoid casting occur or cold tissue. This experience has been successful overseas, our country has not been relevant reports. In modeling terms, instead of silica sand with sand Baozhu, it has the following advantages: 1, the workplace significantly reduce the dust content in the atmosphere, in particular small siliceous dust, which in the future will increasingly become the focus of attention; 2 former sand consumption per tonne of castings can be greatly reduced, saving resources; 3, due to the sand mobility, under the same conditions tight, mold, compaction of the core increase, but still good breathable, help to improve the quality of castings; 4, from the model significantly improved the performance of the sand, it can reduce the appearance of draft angle, reduce time off sand from the mold, helping to improve the dimensional accuracy and surface castings Currently, Sarah is much higher than the price of sand silica sand, although reducing its consumption, just sand, the artificial sand instead of silica sand, the cost is still relatively; quality. However, if for a comprehensive assessment of the overall benefit may be superior to silica sand. Baozhu sand instead of silica sand with many benefits, but an application of new materials, must also have some problems, we need to seriously recognize and understand, and take measures appropriately, such as: (1) iron castings shrinkage, shrinkage Pine tendency production of cast iron parts, especially when ductile iron castings, although higher compaction mold, shaped wall small amount of exercise, there is a tendency to reduce the shrinkage effect, however, the thermal expansion coefficient of just sand Baozhu sand 1/10 Almost no inhibition of silica sand expansion of expandable graphite casting, casting produce shrinkage, shrinkage tends to increase. In most cases, the role of the latter factor is larger than the previous one factor, casting may occur shrinkage, shrinkage type defects. When changing the original sand, process design, through test should correctly grasp the characteristics of used sand set appropriately riser and cold iron. (2) the specific heat capacity of large impact Resin Sand hardening acid-hardening furan resin Resin Sand, resole resin from the hard sand, hardened resin is a condensation reaction, that is, the resin cross-linking reaction, hardening When, to precipitate water, heat is required to evaporate water, escape, and the reaction to continue. Artificial sand specific heat capacity of relatively large, especially melting mullite sand (Baozhu sand), which is almost twice the specific heat capacity of the silica sand. When the resin curing reaction occurs, if too much sand to absorb the resin curing reaction of the separated heat, the sand will affect the hardening rate and initial strength. Because there is the role of other factors, and some foundries, in the orb formulated Furan Resin sand use, we did not find this situation. However, this issue must be careful observation and analysis. ? At this stage, some well-known domestic enterprises and the Pearl of sand coated sand production company already mature response and avoid this problem. V ladle drainage reagent, instead of chromite sand is now ladle drainage agent main varieties sand drainage agent, chromite sand drainage agent. The silica sand filling sand drainage agent is not conducive to free-fall, naturally, poor mobility, easy to cause shed material; good performance chromite sand drainage agent, but serious environmental pollution, high costs. ? The Pearl of sand chromite sand drainage agent is an ideal alternative materials, and its spherical particle shape, can effectively reduce the strength of the sintered layer is conducive to open water drainage sand; while a small proportion of its costs far less than chromium iron ore. In terms of the production of drainage sand, chromite sand Baozhu sand in place has the following advantages: 1, spherical particle shape: particle shape close to the true circle, smooth surface, no bump veins, its good liquidity, which will help open casting; 2, coefficient of thermal expansion Low: having a low thermal conductivity, thermal expansion is small after prevented shed material 3, refractoriness high: The main ingredient is aluminum oxide, so refractoriness ≥1790 ℃, at a certain degree of sintering temperature of molten steel, however, can reduce the sintering The thickness of the layer 4, may be formed in contact with the molten steel and the protective layer are using less floating preventing drainage, permeate the molten steel 5, because Sarah circular sand, sintered layer of particles between the contact points, can effectively reduce the strength of the sintered layer, make use of open water drainage sand 6, in drainage sand, according to the ratio of sand to all with Sarah, Sarah also partially replace sand chromite sand, the price is far below the chromite sand. ? Used to pay attention, to join the drainage agents piled into a packet type, packet type of center to the ladle outlet aligned. When the steel to prevent steel flow directly impact and influence-inclusive rates start pouring gravity.