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The Effect of Reclaim Primary Quality on Moulding Sand Parameters and Quality of Ductile Iron Casting Surface Layer

Kamińska Jadwiga, Angrecki M., Puzio S., Stachowicz M.

Archives of Foundry Engineering

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2022

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Vol. 22, iss. 2

83--88

EN

The aim of the research was to determine the effect of the primary quality of reclaim from dry mechanical reclamation on the strength properties and service life of moulding sands based on this reclaim. Another aim was to establish the effect of the quality of reclaim, sulphur content - in particular, on the surface quality and thickness of the deformed surface layer in ductile iron castings. The research has revealed differences in the strength parameters and service life (mouldability) of sands based on the tested reclaims, depending on the type of the furfuryl resin used, including resins whose synthesis was done as part of the Żywfur project. Examinations of the structure of the surface layer of test castings poured in moulds made of loose self-hardening sands containing the addition of reclaim have confirmed the occurrence of degenerated spheroidal graphite in this part of the casting. It should be noted here that when massive castings with a long solidification time are made, the graphite degeneration effect can be more visible and the layer with the changed structure can increase in thickness. The research has clearly shown that it is necessary to control the parameters of the reclaim, including sulphur content which is transferred from the hardener and accumulates on the grains. This phenomenon has a negative impact not only on the sand strength and technological properties but also on the surface layer of castings.

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Żywice furfurylowe (furanowe)

Wróbel Janusz

Przegląd Odlewnictwa

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2019

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Vol. 69, nr 1-2

18--25

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Organic Moulding Sands for Production of Large-Size Castings

Major-Gabryś K., Hosadyna-Kondracka M.

Archives of Foundry Engineering

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2019

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iss. 3

99--105

EN

Recently, some major changes have occurred in the structure of the European foundry industry, such as a rapid development in the production of castings from compacted graphite iron and light alloys at the expense of limiting the production of steel castings. This created a significant gap in the production of heavy steel castings (exceeding the weight of 30 Mg) for the metallurgical, cement and energy industries. The problem is proper moulding technology for such heavy castings, whose solidification and cooling time may take even several days, exposing the moulding material to a long-term thermal and mechanical load. Owing to their technological properties, sands with organic binders (synthetic resins) are the compositions used most often in industrial practice. Their main advantages include high strength, good collapsibility and knocking out properties, as well as easy mechanical reclamation. The main disadvantage of these sands is their harmful effect on the environment, manifesting itself at various stages of the casting process, especially during mould pouring. This is why new solutions are sought for sands based on organic binders to ensure their high technological properties but at the same time less harmfulness for the environment. This paper discusses the possibility of reducing the harmful effect of sands with furfuryl binders owing to the use of resins with reduced content of free furfuryl alcohol and hardeners with reduced sulphur content. The use of alkyd binder as an alternative to furfuryl binder has also been proposed and possible application of phenol-formaldehyde resins was considered.

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Influence of the Reclaim Addition into the Matrix on the Hardening Process Kinetics of the Moulding Sand with Furfuryl Resin

Jamrozowicz Ł., Kolczyk J., Wojtuń P.

Archives of Foundry Engineering

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2018

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Vol. 18, iss. 1

41--46

EN

Measurements of the hardening process course of the selected self-hardening moulding sands with the reclaimed material additions to the matrix, are presented in the hereby paper. Moulding sands were produced on the „Szczakowa” sand (of the Sibelco Company) as the matrix of the main fraction FG 0,40/0,32/0,20, while the reclaim was added to it in amounts of 20, 50 and 70%. Regeneration was performed with a horizontal mechanical regenerator capacity of 10 t/h. In addition, two moulding sands, one on the fresh sand matrix another on the reclaimed matrix, were prepared for comparison. Highly-fluid urea-furfuryl resin was used as a binder, while paratoluensulphonic acid as a hardener. During investigations the hardening process course was determined, it means the wave velocity change in time: cL = f(t). The hardening process kinetics was also assessed (dClx/dt = f(t)). Investigations were carried out on the research stand for ultrasound tests. In addition strength tests were performed.

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Wpływ dodatku materiału biodegradowalnego jako komponentu dwuskładnikowego spoiwa odlewniczych mas formierskich i rdzeniowych na właściwości spoiwa oraz mas z jego zastosowaniem

Major-Gabryś K., Grabarczyk A., Dobosz S. M., Drożyński D.

Prace Instytutu Odlewnictwa

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2016

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Vol. 56, no. 4

391--399

PL

Rosnące wymagania dotyczące emisji substancji szkodliwych zmuszają przemysł odlewniczy do poszukiwania nowych, bardziej przyjaznych dla środowiska rozwiązań. Do rozwiązań takich mogą należeć: technologie sporządzania mas formierskich i rdzeniowych z zastosowaniem organicznych materiałów biodegradowalnych jako spoiw. Należy jednak pamiętać, że nowe technologie muszą zapewnić wysokie właściwości technologiczne mas formierskich i rdzeniowych. W niniejszym artykule przedstawiono wyniki badań nowych dwuskładnikowych spoiw formierskich, w których część powszechnie stosowanej w praktyce odlewniczej żywicy fenolowo-furfurylowej zastąpiono materiałem biodegradowalnym w postaci polikaprolaktonu (PCL). W artykule przedstawiono badania wpływu materiału biodegradowalnego jako komponentu nowego dwuskładnikowego spoiwa na degradację termiczną spoiwa, jego lepkość oraz na wybrane właściwości technologiczne badanych mas z zastosowaniem nowego spoiwa, w tym ich deformację cieplną oraz elastyczność w temperaturze otoczenia. Przeprowadzone badania wykazały, że zastąpienie w spoiwie części żywicy fenolowo-furfurylowej materiałem biodegradowalnym PCL nie wpływa na degradację termiczną nowego spoiwa, zwiększa natomiast jego lepkość. Masy z zastosowaniem dwuskładnikowego spoiwa charakteryzują się zbliżonymi właściwościami technologicznymi do mas zawierających tylko żywicą fenolowo-furfurylową.

EN

The increasing requirements concerning the emission of hazardous substances force the casting industry to search for new, more environment-friendly solutions. Such solutions may include technologies of developing moulding and core sands with the use of organic biodegradable materials as binders. We should, however, remember that the new technologies must ensure high technological properties of the moulding and core sands. This article presents the results of investigations of new binary moulding binders, where part of the phenol-furfuryl resin commonly applied in casting, was replaced by a biodegradable material in the form of polycaprolactone (PCL). The article discusses the investigations of the effect of the biodegradable material as a component of a new binary binder on the thermal degradation of the binder, its viscosity as well as the selected technological properties of the examined moulding sands, including their thermal deformation and elasticity at ambient temperature. The performed examinations showed that replacing a part of the phenol- furfuryl resin in the binder with the PCL biodegradable material does not affect the thermal degradation of the new binder, while increasing its viscosity. The moulding mixtures with the applied binary binder are characterized by similar technological properties to the moulding sands with the phenol-furfuryl resin only.

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The Compositions: Biodegradable Material – Synthetic Resins as Moulding Sands Binders

Major-Gabryś K., Grabarczyk A., Dobosz S. M.

Archives of Foundry Engineering

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2016

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Vol. 16, iss. 4

75--78

EN

Growing emission requirements are forcing the foundry industry to seek new, more environmentally friendly solutions. One of the solutions may be the technologies of preparing moulding and core sands using organic biodegradable materials as binders. However, not only environmental requirements grow but also those related to the technological properties of moulding sand. Advancing automation and mechanization of the foundry industry brings new challenges related to the moulding sands. Low elasticity may cause defects during assembly of cores or moulds by the manipulators. The paper presents the study of flexibility in the room temperature according to new method and resistance to thermal deformation of self-hardening moulding sands with furfuryl resin, containing biodegradable material PCL. The task of the new additive is to reduce the moulding sands harmfulness to the environment and increase its flexibility in the room temperature. The impact of the additive and the effect of the amount of binder on the properties of mentioned moulding sands were analysed. Studies have shown that the use of 5% of PCL does not change the nature of the thermal deformation curve, improves the bending strength of tested moulding mixtures and increases their flexibility at room temperature.

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Comparison of the Emission of Aromatic Hydrocarbons from Moulding Sands with Furfural Resin with the Low Content of Furfuryl Alcohol and Different Activators

Żymankowska-Kumon S., Bobrowski A., Grabowska B.

Archives of Foundry Engineering

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2016

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Vol. 16, iss. 4

187--190

EN

No-bake process refers to the use of chemical binders to bond the moulding sand. Sand is moved to the mould fill station in preparation for filling of the mould. A mixer is used to blend the sand with the chemical binder and activator. As the sand exits the mixer, the binder begins the chemical process of hardening. This paper presents the results of decomposition of the moulding sands with modified urea-furfuryl resin (with the low content of furfuryl alcohol below 25 % and different activators: organic and inorganic) on a quartz matrix, under semi-industrial conditions. Investigations of the gases emission in the test foundry plant were executed according to the method extended in the Faculty of Foundry Engineering (AGH University of Science and Technology). Article presents the results of the emitted chosen aromatic hydrocarbons and loss on ignition compared with the different activators used to harden this resin. On the bases of the data, it is possible to determine the content of the emitted dangerous substances from the moulding sand according to the content of loss on ignition.

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Regeneracja zużytej masy z żywicą furfurylową na stanowisku laboratoryjnym

Skrzyński M., Dańko R., Czapla P.

Archives of Foundry Engineering

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2014

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Vol. 14, iss. 4 spec.

111--114

PL

W publikacji przedstawiono wyniki badań regeneracji zużytej masy formierskiej z żywicą furfurylową, które zostały przeprowadzone na stanowisku doświadczalnym regeneratora wirnikowego RD-6. W badaniach określano wpływ sposobu prowadzenia procesu odzysku oraz zastosowanej metody odpylania regeneratu (odpylanie końcowe, odpylanie okresowe, odpylanie ciągłe) na jakość odzyskanego regeneratu. Jakość regeneratu określana była poprzez analizę straty prażenia, ilości pyłów powstających w procesie regeneracji oraz na podstawie określenia własności wytrzymałościowych masy formierskiej z regeneratem.

EN

The paper presents the results of the regeneration of spent molding sand with furan resin, which were carried out at the experimental station rotary regenerator RD-6. In studies, the effects of the method of the reclamation process and the extraction of the dust (final dusting, periodic dusting, dusting continuous) on the quality of the recovered regenerate is determined. The quality of the reclaim was determined by analyzing the loss on ignition, the amount of dust generated in the process of regeneration, the sieve analysis and on the basis of determining the mechanical properties of the molding sands prepared with recovered material.

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Wpływ charakteru chemicznego osnowy i spoiwa na właściwości mas ze spoiwami organicznymi

Holtzer M., Drożyński D., Bobrowski A., Mazur M., Isendorf B.

Archives of Foundry Engineering

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2012

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Vol. 12, iss. 1s

69--74

PL

W artykule zamieszczono wyniki badań wpływu rodzaju osnowy piaskowej (piasek kwarcowy, chromitowy i oliwinowy) na właściwości mas (wytrzymałość [...], ścieralność S, przepuszczalność Pu oraz żywotność Ż) przy zastosowaniu spoiw organicznych o charakterze kwaśnym i zasadowym. Najkorzystniejsze właściwości miały masy, w których osnowa i spoiwo miały najbardziej zbliżony charakter chemiczny (piasek kwarcowy i żywica furanowa). Natomiast w miarę wzrostu różnicy charakteru chemicznego osnowy i żywicy właściwości mas znacznie pogarszały się i w skrajnym przypadku, jakim był układ piasek oliwinowi – żywica furanowa masa nie uzyskiwała nawet minimalnych wymaganych parametrów.

EN

The results of investigations of the kind of the sand grains (high-silica, chromite and olivine sand) on moulding sands properties when organic binding agents of an acidic and basic character were applied, are given in the paper. Moulding sands, in which a sand grains and binding agent were of a similar chemical character (high-silica sand and furan resin), exhibited the best qualities. As the difference of the chemical character of the sand grains and binder was increasing the properties of moulding sands significantly worsened. In the extreme case, which constituted the system: olivine sand and furan resin the moulding sand did not reach even the minimum of the required parameters values.