Wyniki wyszukiwania

Filtruj wyniki

  • Czasopisma
  • Autorzy
  • Słowa kluczowe
  • Data
  • Typ

Wyniki wyszukiwania

Wyników: 11
Wyników na stronie: 25 50 75
Sortuj wg:
Pobierz PDF Pobierz RIS Pobierz Bibtex

Abstrakt

Accurate kinetic parameters are vital for quantifying the effect of binder decomposition on the complex phenomena occurring during the casting process. Commercial casting simulation tools often use simplified kinetic parameters that do not comprise the complex multiple reactions and their effect on gas generation in the sand core. The present work uses experimental thermal analysis techniques such as Thermogravimetry (TG) and Differential thermal analysis (DTA) to determine the kinetic parameters via approximating the entire reaction during the decomposition by multiple first-order apparent reactions. The TG and DTA results reveal a multi-stage and exothermic decomposition process in the binder degradation. The pressure build-up in cores/molds when using the obtained multi-reaction kinetic model is compared with the earlier approach of using an average model. The results indicate that pressure in the mold/core with the multi-reaction approach is estimated to be significantly higher. These results underscore the importance of precise kinetic parameters for simulating binder decomposition in casting processes.
Przejdź do artykułu

Bibliografia

[1] Campbell, J. (2011). Molds and cores. Complete Casting Handbook. 1, 155-186. https://doi.org/10.1016/b978-1-85617-809-9.10004-0.

[2] Campbell, J., Svidro, J.T. & Svidro, J. (2017). Molding and casting processes. Cast Iron Science and Technology. 1, 189-206. DOI: 10.31399/asm.hb.v01a.a0006297.

[3] Diószegi, A., Elmquist, L., Orlenius, J. & Dugic, I. (2009). Defect formation of gray iron casting. Intional Journal of Metalcasting. 3(4), 49-58, DOI: 10.1007/BF03355458.

[4] Bobrowski, A., Holtzer, M., Zymankowska-Kumon, S. & Dańko, R. (2015). Harmfulness assessment of moulding sands with a geopolymer binder and a new hardener, in an aspect of the emission of substances from the BTEX group. Archives of Metallurgy and Materials. 60(1), 341-344. DOI: 10.1515/amm-2015-0056.

[5] Grabowska, B., Żymankowska-Kumon, S., Cukrowicz, S., Kaczmarska, K., Bobrowski, A. & Tyliszczak, B. (2019). Thermoanalytical tests (TG–DTG–DSC, Py-GC/MS) of foundry binders on the example of polymer composition of poly(acrylic acid)–sodium carboxymethylcellulose. Joyrnal of Thermal Analysis and Calorimetry. 138(6), 4427-4436. DOI: 10.1007/s10973-019-08883-5.

[6] Kmita, A., Benko, A., Roczniak, A. & Holtzer, M. (2020). Evaluation of pyrolysis and combustion products from foundry binders: potential hazards in metal casting. Jornal of Thermal Analysis & Calorimetgry. 140(5), 2347-2356. DOI: 10.1007/s10973-019-09031-9.

[7] Holtzer, M., Kmita, A., Roczniak, A., Benko, A. (2018). Thermal stability of a resin binder used in moulding sand technology. 73rd World Foundry Congr. "Creative Foundry", WFC 2018 - Proc. (pp. 131-132).

[8] Wan, P., Zhou, J., Li, Y., Yin, Y., Peng, X., Ji, X., & Shen, X. (2021). Kinetic analysis of resin binder for casting in combustion decomposition process. Journal of Thermal Analysis and Calorimetry. 147, 6323-6336. DOI: 10.1007/s10973-021-10902-3.

[9] Wewerka, E.M., Walters, K.L. & Moore, R.H. (1969). Differential thermal analysis of furfuryl alcohol resin binders. Carbon. 7(1), 129-141. DOI: 10.1016/0008-6223(69)90012-8.

[10] Nastac, L., Jia, S., Nastac, M.N. & Wood, R. (2016). Numerical modeling of the gas evolution in furan binder-silica sand mold castings. International Journal of Cast Metals Research. 29(4), 194-201. DOI: 10.1080/13640461.2015.1125983.

[11] Zych, J., Mocek, J., Snopkiewicz, T. & Jamrozowicz, Ł. (2015). Thermal conductivity of moulding sand with chemical binders, attempts of its increasing. Archives of Metallurgy and Materials. 60(1), 351-357. DOI: 10.1515/amm-2015-0058.

[12] Zych, J., Mocek, J. & Kaźnica, N. (2018). Kinetics of gases emission from surface layers of sand moulds. Archives of Foundry Engineering. 18(1), 222-226. DOI: 10.24425/118841.

[13] Perondi, D., Broetto, C.C., Dettmer, A., Wenzel, B.M. & Godinho, M. (2012). Thermal decomposition of polymeric resin [(C29H 24N206)n]: Kinetic parameters and mechanisms. Polymer Degradation and Stability. 97(11), 2110-2117. DOI: 10.1016/j.polymdegradstab.2012.08.022.

[14] Jomaa, G., Goblet, P., Coquelet, C. & Morlot, V. (2015). Kinetic modeling of polyurethane pyrolysis using non-isothermal thermogravimetric analysis. Thermochimica Acta. 612, 10-18. DOI: 10.1016/j.tca.2015.05.009.

[15] Kmita A. Knauer, W., Holtzer, M., Hodor, K., Piwowarski, G., Roczniak, A., & Górecki, K. (2019). The decomposition process and kinetic analysis of commercial binder based on phenol-formaldehyde resin, using in metal casting. Applied Thermal Engineering. 156, 263-275. DOI: 10.1016/j.applthermaleng.2019.03.093.

[16] Ozawa, T. (1976). A modified method for kinetic analysis of thermoanalytical data. Journal of Thermal Analysis. 9(3), 369-373. DOI: 10.1007/BF01909401.

[17] Coats, A.W. & Redfern, J.P. (1964). Kinetic parameters from thermogravimetric data. Nature. 201, 68-69. https://doi.org/10.1038/201068a0.

[18] Gröbler, A., & Kada, T. (1973). Kinetic studies of multi-step thermal degradations of copolymers or polymer mixtures. Journal of thermal analysis. 5, 407-414. DOI: 10.1007/BF01950231.

[19] Takamura, M. (2006). Application of Highly Wear-Resistant Carbon as a Material for Printing Types on Impact Printers. Waseda University.

[20] Fitzer, E., Schaefer, W. & Yamada, S. (1969). The formation of glasslike carbon by pyrolysis of polyfurfuryl alcohol and phenolic resin. Carbon. 7(6), 643-648. DOI: 10.1016/0008-6223(69)90518-1.

[21] Fitzer E. & Schäfer, W. (1970). The effect of crosslinking on the formation of glasslike carbons from thermosetting resins. Carbon. 8(3), 353-364. DOI: 10.1016/0008-6223(70)90075-8.

[22] Shinada, Y., Ota, H. & Ueda, Y. (1985). Gaz thermiquement décomposés à partir de liants organiques. Imono. 57(1), 17-22.

[23] Freeman E.S. & Carroll, B. (1958). The application of thermoanalytical techniques to reaction kinetics: the thermogravimetric evaluation of the kinetics of the decomposition of calcium oxalate monohydrate. The Journal of Physical Chemistry. 62(4), 394-397. DOI:10.1021/j150562a003.

Przejdź do artykułu

Autorzy i Afiliacje

Taishi Matsushita
1
ORCID: ORCID
Dinesh Sundaram
1
ORCID: ORCID
Ilja Belov
1
ORCID: ORCID
Attila Dioszegi
1
ORCID: ORCID

  1. Jönköping University, Sweden

Abstrakt

Sand samples with furan binder were prepared using Sand, Furfuryl Alcohol and Toluene Sulfonic Acid with ratio 100:0.85:0.30. To

identify and quantify gases releasing from furan binder various studies like FTIR, TGA and GC-MS were carried out. After analyzing our

materials using above mentioned characterizations the chemical formula of the Resin and Binder and amount of gases releasing from

composition were confirmed. After studying various reports on pyrolysis process of furan binder calculation of the % of various gases

emitting during pyrolysis process of furan was carried out. Sample of gas collected from mold was analyzed using GC-MS. Based on GCMS

measurement various gases emitting from furan sand mold were identified and their amount were calculate and compared with the

international standers of permissible gas emission limits in a foundry. The purpose of this paper is to assist foundries in pollution

prevention by devising clean technologies which maintain or improve the quality of ambient surrounding. This paper aimed at

minimization of pollution of air by using various techniques.

Przejdź do artykułu

Autorzy i Afiliacje

S.G. Acharya
J.A. Vadher
P.V. Kanjariya

Abstrakt

The goal of this article is to application of non-silica sands based on alumininosilicates as an alternative of traditionally used chromite sand for alloyed steel and iron castings. Basic parameters as bulk density, pH value of water suspension, refractoriness, grain shape of the testing sands were evaluated. Also mechanical properties of furan no-bake moulding mixtures with testing sand were determined. Finally, the influence of non-silica sand on casting quality was evaluated via semi-scale under normal casting production for sand characterization Optimization of production process and production costs were described.

Przejdź do artykułu

Autorzy i Afiliacje

J. Beňo
M. Poręba
ORCID: ORCID
T. Bajer

Abstrakt

The paper focuses on investigation of properties of two most widely used self-set sand binder systems APNB and FNB across the Globe, for making molds and cores in foundries to produce castings of different sizes involving wide range of metals and alloys, ferrous and nonferrous. This includes study of compression strength values of samples made out of molding sand at different binder addition level using new, mechanically reclaimed (MR) and thermally reclaimed (TR) sand. Strength values studied include dry strength (at room temperature) at specified intervals simulating different stages of mold handling, namely stripping and pre heating, followed by degraded strength after application of thinner based zircon wash by brush, subsequent lighting of, then checking strength both in warm (degraded strength) & cold (recovered strength) conditions. Throughout the cycle of mold movement from stripping to knock out, strength requirements can be divided into two broad classifications, one from stripping to closing (dry strength) and another from pouring to knock out (hot & retained strength). Although the process for checking of dry strength are well documented, no method using simple equipments for checking hot & retained strength are documented in literature. Attempts have been made in this paper to use some simple methods to standardize process for checking high strength properties using ordinary laboratory equipments. Temperature of 450°C has been chosen by trial & error method to study high temperature properties to get consistent & amplified values. Volume of gases generated for both binders in laboratory at 850°C have also been measured. Nature of gases including harmful BTEX and PAH generated on pyrolysis of FNB and APNB bonded sands are already documented in a publication [1]. This exercise has once again been repeated in same laboratory, AGH University, Poland with latest binder formulations in use in two foundries in India.

Przejdź do artykułu

Autorzy i Afiliacje

Dipak K. Ghosh

Abstrakt

Mechanical reclamation process of spent moulding sands generate large amounts dusts containing mainly rubbed spent binding agents and quartz dust. The amounts of post-reclamation dusts, depending of the reclamation system efficiency and reclaim dedusting system, can reach 5 -10% in relation to the total reclaimed moulding sand. This dust due to the high content of the organic substances is a threat to the environment and therefore requires the storage on landfills specially adapted for this type of waste. On the other hand, the presence of organic substances causes that these dusts have relatively high energy values that could be used. However, at present there is no coherent, environmentally friendly concept for the management of this type of dust. The paper presents the results of tests of thermal utilization the dusts (as a source of energy) were carried out at AGH University of Science and Technology. Thermal utilization of dusts was carried out in the co-burning with carbon carriers process or in individual burning (Patent PL 227878 B1 and patent application PL - 411 902).

Przejdź do artykułu

Autorzy i Afiliacje

M. Holtzer
R. Dańko
J. Dańko

Abstrakt

Casting covers major area of production all over the world. Resin bonded casting is widely used in today’s manufacturing industries. Furan

No bake casting is most widely accepted in indian foundries due to its excellent surface finish and dimensional stability. It is a self-setting

binder and it has a lower work and strip times. Though the casting process is also known as process of uncertainty, in the present study, an

attempt has been made to investigate the effect of Grain Fineness Number, Loss of Ignition, Potential of Hydrogen, % of Resin with

respect to sand, Sand Temperature and Compressive strength of the mould on Sand Inclusion defect – one of the most dominating defect in

the Krislur Castomech Pvt. Ltd. Industry situated at Bhavnagar, Gujarat, India. The experiments were conducted based on response surface

methodology (RSM) and sequential approach using face centered central composite design. The results show that quadratic model with

removal of some insignificant term is comparatively best fits for Sand Inclusion Defect.

Przejdź do artykułu

Autorzy i Afiliacje

S.G. Acharya
J.A. Vadher
K.D. Kothari

Abstrakt

The paper summarizes research realized by the author in laboratory and industrial conditions (foundries of cast steel and cast iron, castings up to 50 tons) on the effects of the chemically hardened molding sands regeneration using hard/soft rubbing in the dry reclamation. A reference was simultaneously made to advisability of application of the thermal regeneration in conditions, where chromite amount in the circulating (reclaimed) molding sand goes as high as above ten percent. An advisability of connecting standard and specialized methods of examination of the reclaimed sands and molding sands made using it was pointed out. A way of application of studies with the Hot Distortion Plus® method modified by the author for validation of modeling of the thermo-dynamic phenomena in the mold was shown.
Przejdź do artykułu

Autorzy i Afiliacje

Z. Ignaszak
J-B. Prunier

Abstrakt

The results of researches of sorption processes of surface layers of components of sand moulds covered by protective coatings are

presented in the hereby paper. Investigations comprised various types of sand grains of moulding sands with furan resin: silica sand,

reclaimed sand and calcined in temperature of 700oC silica sand. Two kinds of alcoholic protective coatings were used – zirconium and

zirconium – graphite. Tests were performed under condition of a constant temperature within the range 30 – 35oC and high relative air

humidity 75 - 80%. To analyze the role of sand grains in sorption processes quantitavie moisture sorption with use of gravimetric method

and ultrasonic method were used in measurements. The tendency to moisture sorption of surface layers of sand moulds according to the

different kinds of sand grains was specified. The effectiveness of protective action of coatings from moisture sorption was analyzed as

well.

Knowledge of the role of sand grains from the viewpoint of capacity for moisture sorption is important due to the surface casting defects

occurrence. In particular, that are defects of a gaseous origin caused by too high moisture content of moulds, especially in surface layers.

Przejdź do artykułu

Autorzy i Afiliacje

N. Kaźnica
J. Zych

Abstrakt

The furan resin offers advantages such as high intensity, low viscosity, good humidity resistance and is suitable for cast different casting

alloys: steel, cast iron and non-ferrous metal casting. For hardening furan resins are used different hardeners (acid catalysts). The acid

catalysts have significant effects on the properties of the cured binder (e,g. binding strength and thermal stability) [1 - 3]. Investigations of

the gases emission in the test foundry plant were performed according to the original method developed in the Faculty of Foundry

Engineering, AGH UST. The analysis is carried out by the gas chromatography method with the application of the flame-ionising detector

(FID) (TRACE GC Ultra THERMO SCIENTIFIC).

Przejdź do artykułu

Autorzy i Afiliacje

M. Holtzer
R. Dańko
S. Żymankowska-Kumon
A. Bobrowski
A. Kmita

Abstrakt

The subject of this paper was to compare the influence of selected coatings on bending strength of moulds and cores manufactured in a furan technology. In a range of study, there were used three kinds of coatings - water based coating and two kind of alcohol based coating manufactured by FOSECO. Coating were applicated by brush, overpouring/flow and spraying. For each application method, there were realized different kind of drying- at ambient temperature, in a furnace and by burning. Physicochemical properties of coatings were such selected to accommodate them to the application method and type of coating. Based on the conducted studies it was observed that for water based coating application method doesn’t have an important influence on bending strength and it is necessary to optimize the time and temperature of drying to achieve better results of bending strength. For alcohol based coatings, drying by burning causes significant deterioration of bending strength of the mould and core and drying process at ambient allows to obtain high bending strength of mould/cores in regard to time of drying.
Przejdź do artykułu

Autorzy i Afiliacje

J. Dorula
R. Romelczyk
N. Przyszlak
B. Siodmok
A. Studnicki

Abstrakt

The paper presents an original method of measuring the actual chromite content in the circulating moulding sand of foundry. This type of

material is applied for production of moulds. This is the case of foundry which most frequently perform heavy casting in which for the

construction of chemical hardening mould is used, both the quartz sand and chromite sand. After the dry reclamation of used moulding

sand, both types of sands are mixed in various ratios resulting that in reclaimed sand silos, the layers of varying content of chromite in

mixture are observed. For chromite recuperation from the circulating moulding sand there are applied the appropriate installations

equipped with separate elements generating locally strong magnetic field. The knowledge of the current ratio of chromite and quartz sand

allows to optimize the settings of installation and control of the separation efficiency. The arduous and time-consuming method of

determining the content of chromite using bromoform liquid requires operational powers and precautions during using this toxic liquid.

It was developed and tested the new, uncomplicated gravimetric laboratory method using powerful permanent magnets (neodymium).

The method is used in the production conditions of casting for current inspection of chromite quantity in used sand in reclamation plant.

Przejdź do artykułu

Autorzy i Afiliacje

Z. Ignaszak
J-B. Prunier

Ta strona wykorzystuje pliki 'cookies'. Więcej informacji