Improvement of efficiency of use of liquid-glass mixtures. Part 4. Combined strengthening

Krutilin, A. N.; Huminski, Yu. Yu.; Rusevich, O. A.; Kul’bitskaya, L. V.

doi:10.21122/1683-6065-2018-4-38-44

Cited by 6 publications

(3 citation statements)

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“…At the same time, SSS could be solidified by polycondensation mechanism with new solid astringent chemical compounds formation in it or by coagulation mechanism as dehydration result (as dehydration result or certain organic compounds using), its pH value de creasing, silicate modulus increasing, etc. [17].…”

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confidence: 99%

Kinetics of quartz sand and its mixtures drying by microwave radiation

Solonenko¹,

Repiakh²,

Uzlov³

et al. 2021

Nauk. visn. nat. hirn. univ.

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Purpose. Kinetics research and description of drying by microwave radiation mechanism development of quartz sand and its mixes with sodium silicate in limited quantity of water steam medium. Methodology. Distilled water, sodium silicate solute and quartz sand have been used in this research. Study has been performed on sand samples weighing 200 g. Mixtures drying and structuring have been performed by microwave radiation with power of 700W with frequency of 2.45 GHz in air and in saturated water weighing 1 g steam medium. Accuracy of temperature measurement is 1, mass is 0.02 g. Realized in this investigation drying kinetics has been specified as specimen weight change dependence and moisture evaporation from this mixture rate vs. drying duration. Dependencies have been built on the results of video recording and corresponding chrono-gravimetric measurements data digitalization. Mixtures during heating by microwave radiation temperature changes registration has been performed with an interval of 1560 s. Samples average heating rate has been estimated by calculation based on results in their temperature change determination during first 2 minutes of heating with microwave radiation. Findings. For the first time, microwave drying kinetics of quartz sand and its mixtures with sodium silicate in limited water medium (structured by SMS-process) has been studied. For the first time, based on SMS-process material balance, analytical dependence has been developed. This dependence application allows sand-sodium-silicate mixture structured by SMS-process maximum mass to calculate when using sodium silicate solute (silicate module 2.83.0) for quartz sand cladding and 1 g of saturated water steam for mixture structuring. It has been established that when mixtures structuring according to SMS-process water extraction from them takes place in three stages at ~100, 100108 and at 125138 . Maximum appropriate heating temperature of sand-sodium-silicate mixture during structuring by SMS-process has been recommended as ~125 . Exceeding of specified temperature leads to hydrated water from mixture releasing in steam form and its condensation on colder working surface of model-rod rigging. Resulting condensate leads to mixture restructuring in contact with equipment places and, accordingly, sharp quality deterioration in prepared molds and rods. For manufactured molds and rods quality stabilization, it has been recommended to pre-dry the quartz sand cladded with sodium silicate solute in microwave field for at least 3 minutes before structuring according to SMS-process. Originality. For the first time, data on drying kinetics has been obtained and quartz sand and its mixtures with sodium silicate in limited water steam medium microwave drying mechanism description has been developed. Influence of number of SMS-process basic parameters on structured quartz sand weight regularities has been established. Practical value. Research results will be useful in terms of ideas expanding about the processes that accompany granular materials drying, as well as in technologies and equipment for drying and structuring fine-grained dielectric materials and their mixtures development, creating new capillary-porous media, etc. under microwave radiation influence.

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confidence: 99%

Kinetics of quartz sand and its mixtures drying by microwave radiation

Solonenko¹,

Repiakh²,

Uzlov³

et al. 2021

Nauk. visn. nat. hirn. univ.

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“…Cooling of such castings starts from the outside during solidification under normal conditions. The temperature of the inside layers exceeds the temperature of the surface layers in this process [2]. After reaching the ambient temperature, the surface layers stop shortening due to a decrease in temperature.…”

Section: Review Of Well-known Publications and Researchesmentioning

confidence: 96%

Influence of external and internal cooling at solidification on strength of brittle duralumin in compression

et al. 2018

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The causes of the occurrence and influence of inherent stresses, unevenly distributed across the cross section, on the strength of materials are analyzed. Methods of creating artificial distribution of inherent stresses with opposite signs in comparison with the usual distribution obtained with natural solidification of the material are given. The sequence of an experiment on cylindrical specimens made of epoxy resin and brittle silicate aluminum alloy in creating distributions of inherent stresses with opposite signs is described. The results of experimental tests of the influence of inherent stresses unevenly distributed across the cross section, on the strength of the epoxy resin and of the fragile silicate aluminum alloy with compression are given. Quantitative characteristics of the influence of unevenly distributed inherent stresses on the strength of materials under compression are obtained. The reasons of the influence of inherent stresses on the strength of materials under compression are analyzed and grounded.

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“…However, many researchers who have examined this problem confirmed the facts of presence of substantial deficiencies for these setting mechanisms [7][8][9][10]. So, the process of silica gel forming as a result of a known chemical reaction of waterglass blowing by carbon dioxide via CO 2 process is characterized by low conduction rate in the normal temperature conditions.…”

Section: Introductionmentioning

confidence: 99%

Production of moulding cores and waterglass mixtures using “dry ice” for steel and iron casting

Leushin¹,

Leushina²,

Balabanov³

et al. 2021

cisisr

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Increased interest of industrial enterprises to manufacture of moulding cores and moulds of mixtures based on waterglass binder is connected with acceptability and high ecological safety of this material. It stipulated more active work for searching technical solutions that can decrease or exclude deficiencies of such technologies as carbon dioxide blowing and thermal effect that are mostly popular at Russian enterprises. Among these deficiencies, the following can be mentioned for example: low setting rates during blowing of waterglass mixtures in the normal temperature conditions as well as the effect of noncontrolled moisture migration in a moulding core of mould body during heating. Their appearances lead to deterioration of operation parameters of core or mould, such as lowering of surface strength, increase of friability, elevation of strength of internal parts of core or mould, what enlarges the risk of their poor knock-out ability from steel and iron castings. Analytical survey of accessible information data was conducted by the authors of this paper; they revealed two directions in searching the solution of the a.m. problem that were supported by overwhelming majority of the researchers. These directions include directed vacuum treatment of technological accessories for increase of control abilities of moisture migration in a body of core or mould, as well as technological additives of different origination in the mixture composition for provision of timely softening of core or mould during knock-out operation out of casting. However, their use does not guarantee always the stable positive effect, thereby this task is still not solved. The authors of this paper concentrated their attention on the problem of development and testing the innovative technology of production of moulding cores and moulds of waterglass mixtures in the conditions of operating enterprise. This technology allows to improve their operating properties and parameters, to lower the mentioned deficiencies and as a result to stabilize the quality of cast metallic billets of steel and iron at the high level. Solving of this task is based on well-known combination of chemical and physical mechanisms of setting of waterglass mixtures together with directed vacuum treatment of technological accessories during acquiring of the required geometrical shape by a moulding core or mould. In this case the following consequent operations tale place: filling of moulding core or moulding box accessories by mixture; its compacting and strengthening via passing of heated setting gas through the mixture from the one side of core or mould with simultaneous its consumption from the other side due to adjustable exhausting. The authors substantiated scientifically and proved experimentally expedience of introduction of small amount of solid carbon dioxide ("dry ice") in the form of particles with preset size and compensation of inevitably occurring undesirable endothermic effect of setting gas heating (air in this case) up to higher temperature in comparison...

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Improvement of efficiency of use of liquid-glass mixtures. Part 4. Combined strengthening

Cited by 6 publications

References 0 publications

Kinetics of quartz sand and its mixtures drying by microwave radiation

Kinetics of quartz sand and its mixtures drying by microwave radiation

Influence of external and internal cooling at solidification on strength of brittle duralumin in compression

Production of moulding cores and waterglass mixtures using “dry ice” for steel and iron casting

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