| The reduced of the environment pollution of the casting industry and the realization of green clean casting production had become the foundry-man author' s urgent duty. Compared with the dust pollution and the black pollution and the resin granulated substance produces which with the clay granulated substance had chemistry pollution , the inorganic cementing agent, the sodium silicate granulated substance was the most possibility to realize the green clean casting production molding sand craft. Our country 70% above steel casting and large-scale casted the iron stock matter to apply the siliceous sand stone craft production, the consumption of sodium silicate was 3 000 000 ton one year, the sodium silicate granulated substance was 60 000 000 ton.Sodium silicate price was cheap, supply abundant, mixed the granulated substance, the process of the modelling and pours do not release the noxious gas, was easy to realize the clean production. But after the sodium silicate pours the being defeated and dispersed difference, was difficult with the old granulated substance sales commission, abandons mostly directly, creates the environment the alkalinity pollution, we do not overcome collapsibity, without knowing where to begin mentions. Then the sodium silicate granulated substance was unable to adapt to the characteristics of the production of the 21st century. Therefore it was the necessity to begin from the sodium silicate granulated substance being defeated and dispersed difference mechanism, the analysis of the sodium silicate sand stone collapsibity and discovers the solution collapsibity. To meet the request of the steel casting foundry of the Hu Nan Heng Yang, at the same time, solve this factory' s problem of the sodium silicate granulated substance being defeated and dispersed.Through the related analysis and research, we had conducted the systemresearch to this factory sodium silicate and the sodium silicate granulated substance craft.1. Through simulation analysis of typical steel castings granulated substance carryed on the granulated substance being heated temperature field, discover the different wall thickness steel casting (core) the granulated substance the high temperature region thickness, drawed the steel casting wall thickness with the high temperature region thickness curve, the fitting non-linearity regression equation, in order to figure out granulated substance high temperature region thickness and choice the appropriate solution of collapsibity;2. The existing several kinds of the medicinal of collapsibity in the market and the own collapsibity preparated to carry on the experimental contrast, discovered one kind or several kinds of the defeated and dispersed medicinal to meet this factory request, and carryed on the actual production test;3. For further reduce the sodium silicate, carryed on the organic ester hardening sodium silicate experiments, and the actual production test;4. the collapsibity of sodium siliceous sand carryed on further analyzes, the synthesis each experiment discovered the reasonable solutions to solve collapsibity.This topic passing (core) the granulated substance being heated temperature field simulation analysis figured out the high temperature area thickness, then the differences of defeated and dispersed in view of the different region and different temperature application the medicinal preparation and the different processing method achieved the solution of collapsibity.1. We analyzed and computed to the molding sand in temperature field, and divided out the core the region temperature distribution situation, discovered the wall thickness or the modulus and the molding sand being heated thickness relations and fitted the wall thickness and the moldingsand heated thickness relations curve and the equation through Spss software. At the same time, we calculated the molding sand being heated high temperature region2.The modulus was smaller than 70 steel castings regarding the middle and small scale casting, mainly solve 700~900°C section to be defeated and dispersed the nature, this stage sodium silicate itself agglutinates, we may append collapsibity medicinal preparation (for example the defeated and dispersed medicinal preparation in sixth chapter of third) to destroy the sodium silicate to stick the conjunctiva the continuity, thus the improvement sodium silicate granulated substance was defeated and dispersed the nature.3. The modulus was bigger than 70 (molding sand high temperature region was thick) the steel casting regarding the large-scale steel casting, affect it' s temperature section not only 700~900°C sodium silicate itself the residual intensity peak value but also have 1300~1500°C sodium silicate itself and silicone sand agglutinating. For not having the sintering point in the high temperature area (core) the granulated substance, we depended upon decreases the sodium silicate to append, then may solve collapsibity;for agglutinates (core) in the high temperature area the granulated substance, obtains the non-linearity regression equation through the simulation and calculate of the thickness of the high temperature area, dealed with this region with the special sand (for example chromate sand).4. Improved the original sand' s quality to reduce the sodium silicate: Through improves the original sand to reduce the sodium silicate. Organic ester sodium silicate hardening craft may fully display the sodium silicate efficiency, and obtained the same caking intensity under the same condition.5. The mechanism of sodium silicate sand in high temperature (higher than 1400°C) : sand sintering point depended on SiO2 content, the sinteringpoint of the majority of quartz sands (man-made quartz sand was anexception) undulate in 1350°C~1550°C. If the steel casting pours, the region ' s temperature maintain at the sinteringpoint temperature province, from thermodynamics viewpoint, this process system was reduce, caused the sodium silica tegranulated substance to produce agglutinates, agglutinated the body to be opposite in the sodium silicate granulated substance body in the certain condition temporary lodging in the energy low condition. |
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