Application of microwaves for innovative hardening of environment-friendly water-glass moulding sands used in manufacture of cast-steel castings

Stachowicz, M.; Granat, K.; Nowak, D.

doi:10.1016/s1644-9665(12)60184-8

Cited by 21 publications

(18 citation statements)

References 3 publications

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“…), which may be of significance for the speed at which the bridges binding the matrix grains plasticize. When cooled down to the ambient temperature, all of the samples crumbled in the middle, which confirms findings [22,27,30] from recent research into microwave heating used for the curing of molding sand with hydrated sodium silicate.…”

Section: Resultssupporting

confidence: 87%

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Impact of Density Degree and Grade of Inorganic Binder on Behavior of Molding Sand at High Temperature

Stachowicz

Paduchowicz

Granat

2017

jcme

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This paper discusses the impact of high temperatures (up to 900°C) on molding and core sand with inorganic binders selected from among the group of unmodified grades of hydrated sodium silicate (water-glass). Molding sands with medium quartz sand were made under laboratory conditions and compacted at the different energy inputs necessary for obtaining various apparent densities (ϱ 0 ). Due to the different composition and apparent density of molding mixtures hardened via microwaves at a frequency of 2.45 GHz, it was possible to assess their deformation (L) at a high temperature above the binder's eutectic temperature. For this purpose, an apparatus for hot distortion tests was used whose construction and equipment allows us to measure the thermoplastic deformations in molding sand in many aspects; i.e., in its time of annealing. The article proposes new possibilities of interpreting the hot distortion phenomena in comparative studies of molding materials and mixtures. The application of this new measurement method revealed the differences between molding mixtures made with five inorganic binders with a molar module ranging from 2.0 to 3.4 and apparent density ranging from 1.34 to 1.57 g/cm 3 . It was established that distortions under the influence of high temperatures last the longest in molding sand with a binder with the highest molar module (3.4). Research also revealed that the density of molding sand is significant for increasing/decreasing the rate of thermoplastic deformations following the heating of samples only if the molding sand includes binders with a molar module of between 3.0 to 3.4. For molding sand with binders with molar modules from 2.0 to 2.5, it was established that this is excessively susceptible to thermoplastic deformation.

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Section: Resultssupporting

confidence: 87%

“…However, the pouring of liquid metal causes greater damage in molding sand with hydrated sodium silicate as the binder [7,22]. In order to explain this phenomenon, it seems the analyses of molding sands at high temperatures will be of key importance.…”

Section: Introductionmentioning

confidence: 99%

Impact of Density Degree and Grade of Inorganic Binder on Behavior of Molding Sand at High Temperature

Stachowicz

Paduchowicz

Granat

2017

jcme

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“…According to the TG-DTA results, the first mass loss between room temperature and 150 ºC corresponds to the vaporization of solvent moisture and desorption of water which might be the main reason for the increase of the strength of the sand moulding within the temperature range of 25 to 150 ºC. Similar results have been observed in previous reports on clay [31,32] and sodium silicate [33] moulding sands. When the preheating temperature was increased to 150-400 ºC, the thermal decomposition of resin film is probably related to the chain scission of weak chemical bonds.…”

Section: Discussionsupporting

confidence: 87%

Effect of reclaimed sand additions on mechanical properties and fracture behavior of furan no-bake resin sand

Liu

et al. 2017

China Foundry

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National Engineering Research Center of Light Alloy Net Forming and State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China; 2. Shanghai Light Alloy Net Forming National Engineering Research Center Co., Ltd., Shanghai 201615, China F uran no-bake resin sands possess a good combination of high dimension accuracy, good surface finish, and room temperature curing, which make them attractive for industrial applications of producing moulds for different kinds of castings, such as steel, iron and non-ferrous alloy castings [1][2][3] . However, it is commonly considered that after pouring, the furan no-bake resin sand may exhibit some shortcomings, such as poor collapsibility, various types of gases released, residual resin, and waste sand, which would cause environmental pollution, increased casting production cost and waste of natural resources [4,5] . Furthermore, the foundry industry is under great pressure due to national policy restrictions on resource conservation and environmental protection [6][7][8][9] . Therefore, the low cost, effective, and eco-friendly furan Abstract: In this work, the effects of reclaimed sand additions on the microstructure characteristics, mechanical properties and fracture behavior of furan no-bake resin sand have been investigated systematically within the temperature range from 25 to 600 ºC. The addition of 20%-100% reclaimed sand showed dramatic strength deterioration effect at the same temperature, which is associated with the formation of bonding bridges. Both the ultimate tensile strength (UTS) and compressive strength (CS) of the moulding sand initially increase with the increase of temperature, and then sharply decrease with the further increase of temperature, which is attributed to the thermal decomposition of furan resin. The addition amount of reclaimed sand has a remarkable effect on the room temperature fracture mode, i.e., with the addition of 0-20% reclaimed sand, the fracture mode was mainly cohesive fracture; the fracture mode converts to be mixture fracture mode as the addition of reclaimed sand increases to 35%-70%; further increasing the addition to 100% results in the fracture mode of typical adhesive fracture. The fracture surface of the bonding bridge changes from a semblance of cotton or holes to smooth with the increase of test temperature. The application of reclaimed sand has a clear economical advantage for mass production of components due to their short reprocessing cycle and low assembly costs. Previous research found the possibility of reclaimed sand in casting, i.e., green moulding sand [10][11][12][13][14][15] , furan resin sand [16][17][18][19] , and sodium silicate sand [20][21][22] . It was found that the mixture of reclaimed sand and new sand satisfies the standards for moulding sands, and sustainable sand casting was developed. In the process of casting, heat will be generated through liquid metals so that the temperature of the moulding sand may be ...

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“…Due to producing no poisonous or irritant gas in the process of mixed sand shell moulding, hardening and casting, the studies of water glass moulding are attracting more and more attention in recent years [1] [2]. Among them, sodium silicate (Na 2 O·mSiO 2 ) is commonly used in the moulding and casting, the second is the potassium sodium silicate (K 2 O·mSiO 2 ), besides, the lithium sodium silicate (Li 2 O·mSiO 2 ) is also widely used. On account of widespread application of sodium silicate, it is taken as an example to carry out deep studies.…”

Section: Introductionmentioning

confidence: 99%

Influences of SiO<sub>2</sub>/Na<sub>2</sub>O Molar Ratio on Aging and Chemical Modification of Water Glass

Yang¹,

Xu²,

Frank³

et al. 2016

OJIC

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In this paper, the content of water glass before and after adding modifying agent was measured by Trimethylsilyl-gas-chromatography. The experimental results showed that different modulus of water glass could generate different content of mono-silicate acid and oligomeric silicate acid in water glass. After a period of storage, different modulus of water glass led to decrease of silicate content at different levels. Because higher content of Na 2 O in water glass tended to incur the alkaline polymerization, the occurrence of depolymerization of silicate species would lead to an increase of oligomeric silicate species, resulting in a drawback of silicate species content after a period of storage. And contrary to that, lower content of Na 2 O in water glass tended to incur the acidic polymerization. When the modifying agent was added to the newly made water glass, the amount of mono-silicate acid and oligomeric silicate acid also decreased. In modified water glass, the change of each silicate acid species was less than that in unmodified water glass. These results showed that the modifying agent retarded the aging of water glass. It had remarkable significance on the theory and practical application of water glass chemistry.

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Application of microwaves for innovative hardening of environment-friendly water-glass moulding sands used in manufacture of cast-steel castings

Cited by 21 publications

References 3 publications

Impact of Density Degree and Grade of Inorganic Binder on Behavior of Molding Sand at High Temperature

Impact of Density Degree and Grade of Inorganic Binder on Behavior of Molding Sand at High Temperature

Effect of reclaimed sand additions on mechanical properties and fracture behavior of furan no-bake resin sand

Influences of SiO<sub>2</sub>/Na<sub>2</sub>O Molar Ratio on Aging and Chemical Modification of Water Glass

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Application of microwaves for innovative hardening of environment-friendly water-glass moulding sands used in manufacture of cast-steel castings

Cited by 21 publications

References 3 publications

Impact of Density Degree and Grade of Inorganic Binder on Behavior of Molding Sand at High Temperature

Impact of Density Degree and Grade of Inorganic Binder on Behavior of Molding Sand at High Temperature

Effect of reclaimed sand additions on mechanical properties and fracture behavior of furan no-bake resin sand

Influences of SiO&lt;sub&gt;2&lt;/sub&gt;/Na&lt;sub&gt;2&lt;/sub&gt;O Molar Ratio on Aging and Chemical Modification of Water Glass

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Influences of SiO<sub>2</sub>/Na<sub>2</sub>O Molar Ratio on Aging and Chemical Modification of Water Glass