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1
Content available The Influence of Various Matrixes on the Strength Properties of Moulding Sands with Thermally Hardened Hydrated Sodium Silicate for the Ablation Casting Process
Major-Gabryś Katarzyna, Puzio Sabina, Bryłka Agata, Kamińska Jadwiga
Journal of Casting & Materials Engineering
|
2021
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Vol. 5, no. 2
31--35
EN
The essence of ablation casting technology consists in pouring castings into single-use moulds made from the mixture of sand and a water-soluble binder. After pouring the mould with liquid metal yet while the casting is still solidifying, the mould destruction (washing out, erosion) takes place using a stream of cooling medium, which in this case is water. This paper focuses on the selection of moulding sands with hydrated sodium silicate for moulds used in ablation casting. The research is based on the use of water glass 145 and 150 as binders. As part of the research, loose moulding mixtures based on two silica sands from different sand mines with different content of binders were prepared. The review of literature data and the results of own studies have shown that moulding sand with hydrated sodium silicate hardened by dehydration is characterized by sufficient strength properties to be used in the ablation casting process. Our own research also confirmed the possibility of using these sand mixtures in terms of both casting surface quality and sand reclamation. The results presented in this paper prove that both sand grains and types of binder tested may be used as components in moulding sands devoted to ablation casting.
2
Content available Influence of Microwave Heating on the Molding Mass with Gypsum Binder Structure and Strength
Paduchowicz Patrycja J., Granat K., Biały P.
Archives of Foundry Engineering
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2021
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Vol. 21, iss. 1
113--118
EN
The paper presents results of influence microwave drying on strength and technological properties of molding sand with gypsum binder researches, which, immediately after making and after the natural initial setting in air for 1, 2 or 5 hours, was heated with 250 W microwave power for 3, 6, 9 and 12 min time periods. The test was carried out on a mass containing (% -wt.): 88% Grudzeń-Las quartz sand, 12% "Dolina Nidy" plaster gypsum and 6% water. The loss of moisture content during natural drying and then microwave drying was determined, significant from the point of view of using the mass with gypsum binder in the production of products, using an environmentally friendly technology without casting incompatibilities. Additionally, the compressive strength of the mass was measured. The influence of both drying methods on the binder crystallization process and the associated mass strength was demonstrated, especially in terms of the possibility of selecting parameters and / or intensifying a specific drying method for use in the technology of manufacturing molds and foundry cores.
3
Content available Implementation of Nanoparticles in Materials Applied in Foundry Engineering
Kmita A., Roczniak A.
Archives of Foundry Engineering
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2017
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Vol. 17, iss. 3
205--209
EN
The ceaseless progress of nanotechnology, observed in the last years, causes that nanomaterials are more and more often applied in several fields of industry, technique and medicine. E.g. silver nanoparticles are used in biomedicine for disinfection and polymer nanoparticles allow insulin transportation in pharmacology. New generation materials containing nanoparticles are also used in the chemical industry (their participation in the commercial market equals app. 53 %). Nanomaterials are used in electronics, among others for semiconductors production (e.g. for producing nanoink Ag, which conducts electric current). Nanomaterials, due to their special properties, are also used in the foundry industry in metallurgy (e.g. metal alloys with nanocrystalline precipitates), as well as in investment casting and in moulding and core sand technologies. Nanoparticles and containing them composites are applied in several technologies including foundry practice, automotive industry, medicine, dentistry etc. it is expected that their role and market share will be successively growing.
4
Content available Effect of Microwave Heating on Moulding Sand Properties with Gypsum Binder
Paduchowicz P., Stachowicz M., Granat K.
Archives of Foundry Engineering
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2017
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Vol. 17, iss. 3
97--102
EN
The paper presents results of initial research on the possibility of applying microwave radiation in an innovative process of making casting moulds from silica sand, where gypsum CaSO4∙2H2O was acting as a binding material. In the research were compared strengths and technological properties of moulding mixture subjected to: natural bonding process at ambient temperature or natural curing with additional microwave drying or heating with the use of microwaves immediately after samples were formed. Used in the research moulding sands, in which dry constituents i.e. sand matrix and gypsum were mixed in the ratio: 89/11. On the basis of the results of strength tests which were obtained by various curing methods, beneficial effect of using microwaves at 2.45 GHz for drying up was observed after 1, 2 and 5 hours since moisture sandmix was formed. Applying the microwaves for hardening just after forming the samples guarantees satisfactory results in the obtained mechanical parameters. In addition, it has been noted that, from a technological and economic point of view, drying the silica sand with gypsum binder in microwave field can be an alternative to traditional molding sand technologies.
5
Content available Effect of Alloy Additions on the Structure and Mechanical Properties of the AlSi7Mg0.3 Alloy
Pisarek B. P., Rapiejko C., Szymczak T., Pacyniak T.
Archives of Foundry Engineering
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2017
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Vol. 17, iss. 1
137--142
EN
The study presents the results of the investigations of the effect of Cu, Ni, Cr, V, Mo and W alloy additions on the microstructure and mechanical properties of the AlSi7Mg0.3 alloy. The examinations were performed within a project the aim of which is to elaborate an experimental and industrial technology of producing elements of machines and devices complex in their construction, made of aluminium alloys by the method of precision investment casting. It was demonstrated that a proper combination of alloy additions causes the crystallization of complex intermetallic phases in the silumin, shortens the SDAS and improves the strength properties: Rm, Rp0.2,HB hardness. Elevating these properties reduces At, which, in consequence, lowers the quality index Q of the alloy of the obtained casts. Experimental casts were made in ceramic moulds preliminarily heated to 160 °C, into which the AlSi7Mg0.3 alloy with the additions was cast, followed by its cooling at ambient temperature. With the purpose of increasing the value of the quality index Q, it is recommended that the process of alloy cooling in the ceramic mould be intensified and/or a thermal treatment of the casts be performed (ageing) (T6).
6
Content available Influence of the Selected Factors on the Ceramic Moulds Permeability Determined by the New Method
Kolczyk J., Zych J., Jamrozowicz Ł.
Archives of Foundry Engineering
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2015
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Vol. 15, iss. 1 spec.
55--60
EN
Ceramic moulds in the investment casting technology are made by depositing on the wax pattern subsequent layers of a liquid ceramic mass together with a granular matrix. A quality of castings depends on building of individual layers. The results of the ceramic moulds permeability obtained by means of the newly developed measuring method are presented in the hereby paper. Due to the applied solution it is possible to perform measurements also for the first layers which have the decisive influence on a permeability of the whole multilayer ceramic mould. Investigations of the influence of the matrix grain size and annealing temperature on the permeability of ceramic moulds were carried out.
7
Content available Kinetics of the σ Phase Precipitation in Respect of Erosion-corrosion Wear of Duplex Cast Steel
Brodziak-Hyska A., Stradomski Z., Kolan C.
Archives of Foundry Engineering
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2014
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Vol. 14, iss. 1
17--20
EN
The examined material comprised two grades of corrosion-resistant cast steel, namely GX2CrNiMoN25-6-3 and GX2CrNiMoCuN25-6-3-3, used for example in elements of systems of wet flue gas desulphurisation in power industry. The operating conditions in media heated up to 70°C and containing Cl- and SO4 ions and solid particles produce high erosive and corrosive wear. The work proposes an application of the σ phase as a component of precipitation strengthening mechanism in order to increase the functional properties of the material. The paper presents the results of examination of the kinetics of σ phase precipitation at a temperature of 800°C and at times ranging from 30 to 180 minutes. Changes in the morphology of precipitates of the σ phase were determined using the value of shape factor R. Resistance to erosion-corrosion wear of duplex cast steel was correlated with the kinetics of sigma phase precipitating.
8
Content available remote Water mist effect on cooling process of casting die and microstructure of AlSi9 alloy
Władysiak R.
Archives of Foundry Engineering
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2010
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Vol. 10, iss. 2
185--194
EN
The paper presents the results of crystallization and cooling process of silumin AlSi9 and temperature distribution in the wall of research casting dies made of cast iron and steel in the temperature range 650÷100 oC during casting of silumin using water mist cooling consisting with air compressed (0,3÷0,4 MPa) and water (0,35÷0,45 MPa). It’s shown the nature and rate of change of casting die temperature and the formation of the temperature gradient at the wall thickness in the axis of the nozzle cooling the outer surface of the wall of casting die. Using derivative curves and regression models were compared to the temporary and average speed of crystallization and cooling of the casting in the 75÷200 oC temperature range. The differences of microstructure resulting from a change in the type of casting die, wall thickness of casting and the use of cooling water mist. It has been shown that the use of water mist and the changing wall thickness of die and the casting cooled pointwise lets you control the crystallization process, microstructure and quality of the silumin casting.
9
Content available remote The influence of the conditions of gypsum plaster preparation on its technological properties
Pawlak M.
Archives of Foundry Engineering
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2010
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Vol. 10, iss. 2
95--98
EN
The results of researches on influence of basic preparation parameters, i.e. time and mixing intensity, start and end time of set, dimensional changes and strength of gypsum plaster, are presented in this paper. Determination of mentioned above parameters has a significant meaning because of their influence on quality of gypsum plaster and its susceptibility to even small disturbances during preparation. Tested plaster was prepared in vacuum mixer St. LOUIS 82. Time of mixing was 60÷360 sec., mixer arm rates 150÷420 rpm. It was demonstrated that mixing time influences strongly the setting time and expansion of gypsum plaster , and this influence growths with growing mixing intensity. The intense, short time mixing is beneficial from the viewpoint of dimensional changes minimizing. Minimizing the setting time is the most beneficial at low mixing intensity but significant dimensional changes appear during setting the plaster.
10
Content available remote The influence of sigma phase on erosion and corrosion properties of duplex steel
Stradomski Z., Brodziak A.
Archives of Foundry Engineering
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2010
|
Vol. 10, iss. 3
85--88
EN
The paper presents the results of investigations concerning the influence of σ phase precipitating on the erosion and corrosion properties of ferritic-austenitic cast steel. The object of investigation have been two grades of corrosion-resistant cast steel: GX2CrNiMoCuN25-6-3-3 and GX2CrNiMoN25-6-3. The examinations have involved measurements for obtaining potentiodynamic curves, examination of erosion and corrosion resistance, and microstructural analysis. The supersaturated cast steel and the material after heat treatment have been examined. It has been found that the tribological properties of supersaturated cast steel are worse than those of the supersaturated and annealed cast steel. The highest erosion and corrosion resistance has been achieved as a result of ferrite decomposition δ → γ’+ σ. The examinations of corrosion resistance have revealed that the ageing process after supersaturation do not cause significant changes in the anti-corrosive properties.
11
Content available remote The assessment of hot cracking susceptibility of ferritic-austenitic cast iron
Stradomski Z., Soiński M. S., Stradomski G.
Archives of Foundry Engineering
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2010
|
Vol. 10, iss. 2
159--162
EN
An inspiration to the research work has arisen from the problems related to cracking of massive castings made of ferritic-austenitic cast steel. The shape and the character of crack trajectories indicate that they are hot cracks. Investigations have included two cast steel grades, namely GX2CrNiMoN25-6-3 and GX2CrNiMoCuN25-6-3-3, because some customers had demanded for copper addition which makes possible the ageing treatment; also the alloys with increased carbon content have been investigated and this resulted from difficulties in obtaining sufficiently low carbon content (Cmax 0,03%) in many Polish foundries which are not equipped with argon-oxygen devices for cast steel decarburizing. The method of critical size of a specimen similar in shape to the Hall test specimen has been applied to examine the cast steel susceptibility to hot cracking. The examination results undoubtedly indicate the negative influence of the increased carbon content, especially in the presence of copper. The intercrystalline character of cracks which propagate along the dendritic austenite precipitates suggests that the peritectic reaction occurs in the final stage of solidification, being induced by segregation of the strong austenite-forming alloying elements. The increased hot cracking susceptibility of the ferrite-austenite cast steel containing copper, particularly with simultaneously increased carbon content, indicates that the implementation of production technologies concerning this material should be started with production of castings made of alloy grades without copper addition.
12
Content available remote Influence of the technology of melting and inoculation preliminary alloy AlBe5 on change of concentration of Al and microstructure of the bronze CuAl10Ni5Fe4
Pisarek B.
Archives of Foundry Engineering
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2010
|
Vol. 10, iss. 2
127--134
EN
Examining was the aim of the work: influence of the permanent temperature 1300°C ± 15°C and changing time of isothermal holding in the range 0÷50 minutes on the melting loss of aluminum in the bronze CuAl10Ni5Fe4; the quantity the slag rafining - covering Unitop BA-1 (0÷1,5%) on the effectiveness of the protection of liquid bronze before the oxygenation, the quantity of the preliminary alloy - in-oculant AlBe5 (0÷1,0%) on the effective compensation melting loss of aluminum and time of isothermal holding on the effect of the in-oculation of the bronze and the comparison of the effectiveness of the inoculation of the bronze in furnace and in the form. Introduced investigations resulted from the study of the new grades of the Cu-Al-Fe-Ni bronze with additions singly or simultaneously Si, Cr, Mo and/or W, to melting which necessary it is for high temperature and comparatively long time isothermal holding indispensable to the occur of the process of diffusive dissolving the high-melting of the bronze components. High temperature and lengthening the time of isothermal holding the liquid bronze in casting furnace the melting loss of Al influences the growth. Addition the slag of covering-refining Unitop BA-1 in the quantity 1,5% the bronze protects before the melting loss of aluminum by the time of isothermal holding in the temperature 1300°C about 15 minutes. Addition of the preliminary alloy AlBe5 in the quantity 0,6% it assures the effective compensation of the aluminum which melting loss undergoes for the studied parameters of the melting. The effect of the inoculation of the bronze together with diminishes the preliminary alloy AlBe5 with lengthening the time of isothermal holding. Because of this, use of the method of introducing the preliminary alloy it is seems good solution on the inoculation of aluminum bronzes directly to form, unsensitive on the time of isothermal holding the bronze.
13
Content available remote Crystallization, microstructure and mechanical properties of silumins with micro-additions of Cr, Mo, W and V
Pietrowski S., Szymczak T.
Archives of Foundry Engineering
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2010
|
Vol. 10, iss. 1
123-136
EN
In this paper results of the crystallization, microstructure and mechanical properties studies of hypo-, hyper- and eutectic silumins with addition of: Cr, Mo, W and V in amount of about 0,05% are presented. The influence of Sb, Sr and P together with Ti + B on the silumins crystallization process has been given. Results of: the microstructure, R_m, R_p0,2, A_5 and HB testing of silumins after precipitation hardening and heat treatment in temperature of 560°C/3min and water chilling are presented.
14
Content available remote Cast functional accessories for heat treatment furnaces
Piekarski B., Drotlew A.
Archives of Foundry Engineering
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2010
|
Vol. 10, iss. 4
183--190
EN
The study gives examples of the cast functional accessories operating in furnaces for the heat treatment of metals and alloys. The described design solutions of castings and their respective assemblies are used for charge preparation and handling. They were put in systematic order depending on furnace design and the technological purpose of heat treatment. Basic grades of austenitic cast steel, used for castings of this type, were enumerated, and examples of general guidelines formulated for their use were stated. The functional accessories described in this study were designed and made by the Foundry Research Laboratory of West Pomeranian University of Technology.
15
Content available remote Bainitic-martensitic nodular cast iron with carbides
Gumienny G.
Archives of Foundry Engineering
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2010
|
Vol. 10, iss. 2
63--68
EN
In this paper the possibility obtaining of upper bainite, lower bainite and martensite or their mixture in nodular cast iron with carbides has been presented. Conditions have been given, when in nodular cast iron with carbides for cooling at first in the form, then air-cooling austenite transformation to upper bainite, its mixture with lower bainite and martensite takes place. Transformations proceed during cooling and the crystallization of cast iron have been determined and the casting hardness has been presented.
16
Content available remote Advanced oxidation and adsorption modification of dust waste from standard moulding sands
Baliński A.
Archives of Foundry Engineering
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2010
|
Vol. 10, iss. 2
5--12
EN
The article discusses the process of advanced oxidation (AO) with application of ultrasounds and surface modification of the dust waste collected during dry dedusting of processed moulding sands with bentonite binder. A beneficial effect of both AO and adsorption modification of dust waste, when performed with the selected type of polyelectrolyte, on the technological and mechanical properties of moulding sands prepared with an addition of this dust has been stated. In spite of the bentonite content in moulding sand reduced by 43% and replaced with modified dust waste, the mechanical properties, i.e. the compression and tensile strengths, examined on sand specimens have been improved by 10% and 13%, respectively, with no harm to other basic technological sand properties. At the same time, it was also possible to reduce by about 30% the emission rate of the main gaseous component from the BTEX group, i.e. benzene.
17
Content available remote Dilatometric studies of plaster sandmix in raw and heat treated state
Pawlak M., Niedźwiedzki Z.
Archives of Foundry Engineering
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2008
|
Vol. 8, iss. 3
145-148
EN
Results of dilatometric studies of bounded plaster sandmix applied in precision pressure below atmospheric casting, are presented in this paper. Sandmix composed of half-hydrate alpha-CaSO4ź2H2O with different parts of silica SiO2 was a subject of investigations. Silica is a factor weakening the influence of phase transformations on total distortion of the mould during heating and thus influences the accuracy of prepared cast. Experimental moulders of dimensions 735 made of plaster sandmix with silica fraction equal 30; 40; 50; 60 and 70% were used during studies. Sandmix was tested in raw state and after heat treatment changing the alpha-half hydrate into anhydrite II (CaSO4). It was demonstrated that addition of the silica at level about 50% influences most advantageously on dimension changes of heated sandmix by lowering dilatations 3 times in comparison with sandmix composed of pure alpha-half hydrate. The transformation of plaster structure into anhydrite II is also important - the shrinkability phase disappears and expansion similar to linear-like appears. It was determined that it is possible to obtain sandmix of small, stabile distortion on the way of appropriate selection of components and heat treatment parameters what improves dimensional and shape accuracy limits of the cast and significantly limits internal stresses in the mould eliminating risk of its cracking.
18
Content available remote The influence of organic fibre types on technological parameters in process of ceramic moulds making
Karwiński A., Młodnicki S., Meksa W., Woźnicki G.
Archives of Foundry Engineering
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2007
|
Vol. 7, iss. 2
143-146
EN
The research being presented in this article has been set up with the aim of working out both the technology and starting up manufacturing process ( in which a new generation of ceramic slips is employed ) in "Armatura" precise foundry. There have been used "aqueous" Ekosil silicate binder and quartz ceramic material with addition of organic fibres for making slip in the new technological solution. In the presented research work has been achieved a quantitative and qualitative selection of composition for the ceramic slip. The selection has been based on testing of physico-chemical and technological qualities.
19
Content available remote Ferrous alloys cast under high pressure gas atmosphere
Pirowski Z., Olszyński J., Gwiżdż A.
Archives of Foundry Engineering
|
2007
|
Vol. 7, iss. 1
107-112
EN
The main objective of this paper is describing the essence of the process of introducing nitrogen to the melt of ferrous alloys by application of overpressure above the metal bath. The problem was discussed in terms of both theory (the thermodynamic aspects of the process) and practice (the technical and technological aspects, safety of the furnace stand operation, and technique of conducting the melt). The novel technique of melting under high pressure of the gas atmosphere (up to 5 MPa) has not been used so far in the domestic industry, mainly because of the lack of proper equipment satisfyng the requirements of safe operation. Owing to cooperation undertaken with a partner from Bulgaria, a more detailed investigation of this technology has become possible and melting of selected ferrous alloys was conducted under the gas atmosphere at a pressure of about 3,5 MPa.
20
Content available remote Evaluating the effectiveness of heat-resistant cast steel filtration from the results of structure examinations
Asłanowicz M., Ościłowiski A., Stochańczyk J., Wieliczko P.
Archives of Foundry Engineering
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2007
|
Vol. 7, iss. 1
97-102
EN
Filtration guarantees castings characterised by high quality and free from any non-metallic inclusions, which are formed at the stage of melting and pouring of liquid metal. This article discusses the problem of the effectiveness of filtration process taking as an example heat-resistant cast steel poured into ceramic moulds. In investigations, foamed zircon filters made by FerroTerm Sp. z o.o. Łódź, Poland, were used. The effectiveness of filtration was described and examined using the results of metallographic examinations, including macro- and micro-structure examinations of metal and of cast metal/ceramic filter interface, and measurements of the content of non-metallic inclusions. The methods of investigations were presented, the obtained results were described, and relevant conclusions were drawn, all of them unmistakably indicating a very beneficial effect that filtration has on molten metal quality.
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