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Number of results: 190
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Abstract

The article presents the directions of foundry waste management, mainly used for spent foundry sands (SFS) and dust after the reclamation of this waste. An important aspect of environmental protection in foundry production is the reduction of the amount of generated waste as a result of SFS regeneration. The advantage is the reuse of waste, which reduces the costs of raw materials purchase and environmental fees for landfilling. Non -recycled spent foundry sands can be used in other industries. SFS is most often used in road and construction industries as well as inert material in closed mines (Smoluchowska and Zgut 2005; Bany-Kowalska 2006). An interesting direction of using SFS is its application in gardening and agriculture. The article presents the advantages and disadvantages of such use. It was found that spent foundry sands can be useful for the production of soil mixtures for many agricultural and horticultural applications. Due to the possibility of environmental pollution with heavy metals and organic compounds, such an application is recommended for the so-called green sands, i.e. SFS with mineral binders. In addition, an innovative solution for the energy use of dusts after spent foundry sands reclamation with organic binders has been discussed and proposed by some researchers. It was shown that dust from reclaimed SFS with organic binders can be used as an alternative fuel and raw material in cement kilns, due to the high percentage of organic substances which determine their calorific value and silica.
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Abstract

Within the research, selected multilayer technological systems created as combinations of water-glass containing moulding sand with foundry tooling, were characterised on the grounds of their electrical properties. By measuring resonance frequency and quality factor of a waveguide resonance cavity, real component of permittivity εr′ and loss tangent tgδ were determined for multilayer foundry systems with various qualitative and quantitative compositions. It was demonstrated that combination of a sandmix and foundry tooling with known dielectric properties results in a system with different physico-chemical properties, whose relation to the parameters of individual components of the system is undefined at this research stage. On the grounds of measurement results, theoretical value of microwave heating power, dissipated in unit volume of the selected multilayer foundry system, was determined. Knowledge of theoretical heating power and evaluation of physical, chemical and structural changes occurring in moulding sands exposed to microwaves in such a technological system makes a ground for empirical modelling of the process of microwave heating of foundry moulds and cores.
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Abstract

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.
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Abstract

The publication presents the results of examination of selected carburizers used for cast iron production with respect to their electric resistance. Both the synthetic graphite carburizers and petroleum coke (petcoke) carburizers of various chemical composition were compared. The relationships between electrical resistance of tested carburizers and their quality were found. The graphite carburizers exhibited much better conductivity than the petcoke ones. Resistance characteristics were different for the different types of carburizers. The measurements were performed according to the authors’ own method based on recording the electric current flow through the compressed samples. The samples of the specified diameter were put under pressure of the gradually increased value (10, 20, 50, 60, and finally 70 bar), each time the corresponding value of electric resistance being measured with a gauge of high accuracy, equal to 0.1μΩ. The higher pressure values resulted in the lower values of resistance. The relation between both the thermal conductance and the electrical conductance (or the resistance) is well known and mentioned in the professional literature. The results were analysed and presented both in tabular and, additionally, in graphic form.
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Abstract

The paper presents results of preliminary examinations on possibility of determining binder content in traditional moulding sands with the microwave method. The presented measurements were carried-out using a special stand, the so-called slot line. Binder content in thesandmix was determined by measurements of absorption damping Ad and insertion losses IL of electromagnetic wave. One of main advantages of the suggested new method of binder content measurement is short measuring time.
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Abstract

Due to the presence of harmful substances in resins those mould sands may be hazardous to the natural environment and workers. The general assessment of harmfulness of sands used for molds and cores encompasses 2 basic points: emission of hazardous substances during processes of preparing sands, pouring mold with liquid metals (high temperatures), cooling and shaking-out; possibility of washing out hazardous substances from used sands to the environment, during storage or economic use outside foundries. We present the results of research on the emission of BTEX compounds from mould sands with phenolic resins during pouring liquid metal of different temperature (cast iron and Al alloy). The research was conducted according to the original method prepared by the authors, which has been used for years in cooperation with various foundries (Poland, abroad).
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Abstract

This work presents the technology of making foam plastics patterns used in casting as well as the final shaping stand. The analysis of the sintering process was carried out aiming at determining the influence of the pressure and the time of sintering on the flexural strength properties. The analysis of the research results confirmed that when the sintering pressure grows to the value of Pa =1,7 bar the flexural strength also increases, when the pressure value is higher than that, the degradation of the material takes place and the strength properties decrease.
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Abstract

In the paper, an attempt was made to evaluate the effect of preliminary wetting of high-silica base during preparation of moulding sands containing a selected grade of sodium water-glass, designed for hardening by traditional drying or by electromagnetic microwaves at 2.45 GHz. In the research, some water was dosed during stirring the sandmix before adding 1.5 wt% of the binder that was unmodified sodium water-glass grade 137, characterised by high molar module within 3.2 to 3.4. Scope of the examinations included determining the effect of wetting the base on mechanical parameters like compression, bending and tensile strength, as well as on technological parameters like permeability, abrasion resistance and apparent density. The research revealed a significant positive effect of adding water to wet surfaces of high-silica base grains on mechanical properties and quality of moulding sands hardened by physical methods, in particular by microwave heating
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Abstract

Presented are results of a research on usability of an innovative reclamation process of microwave-hardened moulding sands containing water-glass, combined with activation of binder. After each subsequent stage of reclamation, quality of the reclaimed material was determined on the grounds of measurements of permeability and results of screen analysis. The reclaimed material was next used again to prepare new moulding sand. The sandmix based on high-silica sand prepared with water-glass grade 145, was subject to the following cyclical treatment operations: mixing components, consolidation, microwave hardening, cooling, heating the mould up to 800 °C, cooling to ambient temperature, mechanical reclamation dry and wet. It was found that the used-up and reclaimed sandmix containing water-glass is susceptible to the applied activation process of thermally reacted film of binder and, in addition, it maintains good quality and technological properties of high-silica base. Observations of surfaces of reclaimed high-silica grains with activated film of reacted inorganic binder were carried-out using a scanning microscope. Thanks to properly selected reclamation parameters, the high-silica base can be reused even five times, thus reducing demand for fresh aggregate and inorganic binder.
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Abstract

This work presents the analysis of the final shaping process of the patterns aimed at determining the influence of the pressure and the time of sintering on the resistance to bending. The analysis of the research results proved that when the pressure of the sintering rises and reaches Ps=2.1 bar the resistance to bending increases, above this level of the pressure the resistance value starts decreasing. The time of styrofoam sintering at which the highest bending resistance values were obtained is ts=90 s. When the sintering pressure is less than 2 bar prolongation of the time of sintering over 90 s causes a slight increase in the resistance, however, at higher pressures prolongation of the time of sintering causes submelting of the styrofoam pattern.
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Abstract

Due to the presence of harmful substances in resins those mould sands may be hazardous to the natural environment and workers. The general assessment of harmfulness of sands used for molds and cores encompasses 2 basic points: emission of hazardous substances during processes of preparing sands, pouring mold with liquid metals (high temperatures), cooling and shaking-out; possibility of washing out hazardous substances from used sands to the environment, during storage or economic use outside foundries. We present the results of research on the emission of BTEX compounds from mould sands with phenolic resins during pouring liquid metal of different temperature (cast iron and Al alloy). The research was conducted according to the original method prepared by the authors, which has been used for years in cooperation with various foundries (Poland, abroad).
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Abstract

The presented work discusses the influence of material of foundry mould on the effect of modification of AlSi11 alloy. For this purpose castings were produced in moulds made of four various materials. Castings of the first type were cast in a metal die, the second ones in the conventional mould of bentonite-bound sand, those of the third type in the sand mould with oil binder, the last ones in a shell mould where phenol-formaldehyde resin was applied as a binder. All the castings were made of AlSi11 alloy modified with strontium. For a purpose of comparison also castings made of the non-modified alloy were produced. The castings were examined with regard to their microstructures. The performed investigations point out that the addition of strontium master alloy results in refining of the alloy structure, particularly of the α-phase, causes some morphological changes in the alloy and the refinement of eutectics. The advantageous influence of modifier on the structure of the examined silumin was observed particularly in the case of alloy cast either in the conventional oil-bound sand mould or in the shell mould. The non-modified alloy cast into a metal die exhibits a structure similar to those of modified alloy solidifying in the other moulds. The improvement in both tensile strength and unit elongation suggests that the modification was carried out correctly. The best mechanical properties were found for the alloy cast in a metal die, both with and without modification treatment.
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Abstract

One of the biggest problems for sand casting foundries must be the waste produced from disposable molds. Stricter environmental regulations make it harder to dispose of waste sand, so a truly competitive foundry does no longer only make great products, but also concentrates on a sustainable casting process. While methods for repurposing waste foundry sand are still limited, the internal circulation of such sands proves significant possibilities. This paper will focus on thermal reclamation of foundry sands in a special rotating drum furnace in a central facility to serve several foundries. Thermal reclamation is a process for handling foundry sands in elevated temperatures to combust unwanted substances from reusable base sand. The introduction focuses on background of the Finnish foundry business, the most common sand systems in Finland and their reclaim properties. The experimental part features presentation of the new reclamation plant process and the conducted test runs. The samples collected from each test run have been laboratory tested to assure proper sand quality. The results of this work showed that the reclamation of alkaline phenolic no-bake sands was excellent. Reclamation of green sands did not provide satisfactory results as expected and the reclamation of furan no-bake sands provided mixed results, as the raw material was imperfect to begin with. The most important result of this work is still the successful initiation of a centralized thermal reclamation plant, with the ability to reclaim sands of several foundries. With this all of industrial symbiosis, circular economy and sustainability advanced in Finland, and the future development of this plant provides even further opportunities and a possibility to spread the ideas on a global scale.
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Abstract

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.
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Abstract

The problem of materials selection in terms of their mechanical properties during the design of new products is a key issue of design. The complexity of this process is mainly due to a multitude of variants in the previously produced materials and the possibility of their further processing improving the properties. In everyday practice, the problem is solved basing on expert or designer knowledge. The paper is the proposition of a solution using computer-aided analysis of material experimental data, which may be acquired from external data sources. In both cases, taking into account the rapid growth of data, additional tools become increasingly important, mainly those which offer support for adding, viewing, and simple comparison of different experiments. In this paper, the use of formal knowledge representation in the form of an ontology is proposed as a bridge between physical repositories of data in the form of files and user queries, which are usually formulated in natural language. The number and the sophisticated internal structure of attributes or parameters that could be the criteria of the search for the user are an important issue in the traditional data search tools. Ontology, as a formal representation of knowledge, enables taking into account the known relationships between concepts in the field of cast iron, materials used and processing techniques. This allows the user to receive support by searching the results of experiments that relate to a specific material or processing treatment. Automatic presentation of the results which relate to similar materials or similar processing treatments is also possible, which should make the conducted analysis of the selection of materials or processing treatments more comprehensive by including a wider range of possible solutions.
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Abstract

The work deals with technology Patternless process that combines 3 manufacturing process mold by using rapid prototyping technology, conventional sand formation and 3D milling. It's unconventional technology that has been developed to produce large-sized and heavyduty castings weighing up to several tons. It is used mainly in prototype and small batch production, because eliminating production of models. The work deals with the production of blocks for making molds of gypsum and gypsum drying process technology Thermomold. Into blocks, where were made cavities by milling were casted test castings from AlSi10MgMn alloy by gravity casting. At machining of the mold cavity was varied feed rate of tool of cemented carbide. Evaluated was the surface roughness of test castings, that was to 5 micrometers with feed from 900 to 1300 mm/min. The dimensional accuracy of castings was high at feed rate of 1000 and 1500 mm/min did not exceed 0.025 mm.
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Abstract

The dimensional accuracy of a final casting of Inconel 738 LC alloy is affected by many aspects. One of them is the choice of method and time of cooling the wax model for precision investment casting. The main objective of this work was to study the initial deformation of the complex shape of a rotor blades casting. Various approaches have been tested for cooling a wax pattern. When wax models are air cooled and without clamping in the jig for cooling, deviations from the ideal shape of the casting are very noticeable (up to 8 mm) and most are in extreme positions of the model. When the blade is cooled in the fixing jig in a water environment, the resulting deviations compared to those of air cooling are significantly larger, sometimes up to 10 mm. This itself does not mean that the final shape of the casting is dimensionally more accurate with the usage of wax models, which have smaller deviations from the ideal position. Another deformation occurs when the shell mould is produced around the wax pattern and further deformations emerge while cooling the blade casting. This paper demonstrates the first steps in describing the complex process of deformations occurring in Inconel alloy blades produced with investment casting technology by comparing results of thermal imagery, simulations in foundry simulation software ProCAST 2010, and measurements from a CNC scanning system using a Carl Zeiss MC 850. Conclusions are so far not groundbreaking, but it seems that deformations of the wax pattern and deformations of the castings do in some cases cancel each other by having opposite directions. Describing the whole process of deformations will help increase the precision of blade castings so that the models at the beginning and the blades in the end are the same.
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Abstract

The scope of this work focuses on the aspects of quality and safety assurance of the iron cast manufacturing processes. Special attention was given to the processes of quality control and after-machining of iron casts manufactured on automatic foundry lines. Due to low level of automation and huge work intensity at this stage of the process, a model area was established which underwent reorganization in accordance with the assumptions of the World Class Manufacturing (WCM). An analysis of work intensity was carried out and the costs were divided in order to identify operations with no value added, particularly at individual manufacturing departments. Also an analysis of ergonomics at work stations was carried out to eliminate activities that are uncomfortable and dangerous to the workers' health. Several solutions were proposed in terms of rationalization of work organization at iron cast after-machining work stations. The proposed solutions were assessed with the use of multi-criteria assessment tools and then the best variant was selected based on the assumed optimization criteria. The summary of the obtained results reflects benefits from implementation of the proposed solutions.
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Abstract

Foundry resistance furnaces are thermal devices with a relatively large time delay in their response to a change in power parameters. Commonly used in automation classical PID controllers do not meet the requirements of high-quality control. Developed in recent years, fuzzy control theory is increasingly being used in various branches of economy and industry. Fuzzy controllers allow to introduce new developments in control systems of foundry furnaces as well. Correctly selected fuzzy controller can significantly reduce energy consumption in a controlled thermal process of heating equipment. The article presents a comparison of energy consumption by control system of foundry resistance furnace, equipped with either a PID controller or fuzzy controller optimally chosen.
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Abstract

The paper outlines the methodology of virtual design of a foundry plant as a system. The most important stage in the procedure involves the development of a model defined as a set of data about the system. Model development involves two stages: defining the model’s architecture and specifying the model data in the form of parameters and input-output relationships. The structure is understood as configuration of machines and transport units, representing the sub-systems and system components. As the main purpose of the simulation procedure is to find the characteristics of the system’s behaviour, the merits of the iterative method involving analysis, synthesis and evaluation of results are fully explored.
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Abstract

The work presents the results of examinations concerning the influence of various amounts of home scrap additions on the properties of castings made of MgAl9Zn1 alloy. The fraction of home scrap in the metal charge ranged from 0 to 100%. Castings were pressure cast by means of the hot-chamber pressure die casting machine under the industrial conditions in one of the domestic foundries. The examinations consisted in the determination of the following properties: tensile strength Rm, yield strength Rp0.2, and the unit elongation A5, all being measured during the static tensile test. Also, the hardness measurements were taken by the Brinell method. It was found that the mechanical properties (mainly the strength properties) are being improved up to the home scrap fraction of 50%. Their values were increased by about 30% over this range. Further rise in the home scrap content, however, brought a definite decrease in these properties. The unit elongation A5 exhibited continual decrease with an increase in the home scrap fraction in the metal charge. A large growth of hardness was noticed for the home scrap fraction increasing up to the value of 50%. Further increasing the home scrap percentage, however, did not result in a significant rise of the hardness value any more.
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Abstract

The work presents the results of examinations concerning the influence of various amounts of home scrap additions on the porosity of castings made of MgAl9Zn1 alloy. The fraction of home scrap in the metal charge ranged from 0 to 100%. Castings were pressure cast by means of the hot-chamber pressure die casting machine under the industrial conditions in one of the domestic foundries. Additionally, for the purpose of comparison, the porosity of specimens cut out directly of the MgAl9Zn1 ingot alloy was also determined. The examinations consisted in the qualitative assessment of porosity by means of the optical microscopy and its quantitative determination by the method of weighting specimens in air and in water. It was found during the examination that the porosity of castings decreases with an increase in the home scrap fraction in the metal charge. The qualitative examinations confirmed the beneficial influence of the increased home scrap fraction on the porosity of castings. It was concluded that the reusing of home scrap in a foundry can be a good way of reduction of costs related to the production of pressure castings.
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Abstract

In the paper, a research on effects of baking temperature on chromite sand base of moulding sands bonded with sodium silicate is presented. Pure chromite sand and its chromite-based moulding sand prepared with use of sodium silicate were subjected to heating within 100 to 1200 °C. After cooling-down, changes of base grains under thermal action were determined. Chromite moulding sand was prepared with use of 0.5 wt% of domestic made, unmodified sodium silicate (water-glass) grade 145. After baking at elevated temperatures, creation of rough layer was observed on grain surfaces, of both pure chromite sand and that used as base of a moulding sand. Changes of sand grains were evaluated by scanning microscopy and EDS analyses. It was found that changes on grain surfaces are of laminar nature. The observed layer is composed of iron oxide (II) that is one of main structural components of chromite sand. In order to identify changes in internal structure of chromite sand grains, polished sections were prepared of moulding sand hardened with microwaves and baked at elevated temperatures. Microscopic observations revealed changes in grains structure in form of characteristically crystallised acicular particles with limited magnesium content, intersecting at various angles. EDS analysis showed that these particles are composed mostly of chromium oxide (III) and iron oxide (II). The temperature above that the a.m. changes are observed in both chromite-based moulding sand and in pure chromite sand. The observed phenomena were linked with hardness values and mass of this sand.
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Abstract

The paper presents the results of analyzes of gases emitted during exposure to high temperature foundry molding sands, where binders are organic resins. As a research tool has been used special gas chromatograph designed to identify odorous compounds including the group of alkanes.
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