Nauki Techniczne

Archives of Foundry Engineering

Zawartość

Archives of Foundry Engineering | 2018 | vol.18 | No 2 |

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Light weight, low density with high mechanical properties and corrosion resistance, aluminum is the most important material and is commonly used for high performance applications such as aerospace, military and especially automotive industries. The researchers who participate in these industries are working hard to further decrease the weight of end products according to legal boundaries of greenhouse gases. A lot of research was undertaken to produce thin sectioned aluminum parts with improved mechanical properties. Several alloying element addition were investigated. Yet, nowadays aluminum has not met these expectations. Thus, composite materials, particularly metal matrix composites, have taken aluminum’s place due to the enhancement of mechanical properties of aluminum alloys by reinforcements. This paper deals with the overview of the reinforcements such as SiC, Al2O3 and graphene. Graphene has recently attracted many researcher due to its superior elastic modulus, high fatigue strength and low density. It is foreseen and predicted that graphene will replace and outperform carbon nanotubes (CNT) in near future.
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The morphology, chemical composition and formation mechanism of non-metallic inclusions in magnetic alloy of Fe-Co-Ni-Cu-Al-Ti-Hf system were investigated. These alloys are used in manufacturing single-crystal permanent magnets. Modern methods for the identification of non-metallic inclusions, as well as computer simulation of the processes of their formation by Thermo Calc software were used in the work. It was found that studied alloy contains (Ti, Hf)S titanium and hafnium sulfides, (Ti, Hf)2SC titanium and hafnium carbosulfides, Ti2O2S titanium oxisulfide, HfO2 hafnium oxide, and Al2O3 aluminum oxide. No titanium and hafnium nitrides were found in the alloy. The bulk of nonmetallic inclusions are (Ti, Hf)2SC carbosulfides and (Ti, Hf)S sulfides. All carbides and many oxides are within carbosulfides and sulfides. When the sulfur content in the alloy is no more than 0.2%, and carbon content does not exceed 0.03%, carbosulfides are formed in the solidification range of the alloy and has an faceted compact form. If the sulfur content in the alloy becomes more than 0.2% and carbon content more than 0.03%, the carbosulfide formation begins before the alloy solidification or at the beginning stages of solidification. In this case, carbosulfides are dendritic and coarse. Such carbosulfides actively float in the solidified melt and often come to the surface of the castings. In this case, specific surface defects are formed in single-crystal magnets, which are called sulfide stains. All titanium and hafnium sulfides are formed at the lower part of solidification range and have elongated shape.
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This article discusses the influence of Tungsten Inert Gas (TIG) surfacing of duplex cast steel on its hardness and structure. The samples of 24Cr-5Ni-2.5Mo ferritic-austenitic cast steel were subjected to single-overlay processes with the use of solid wire having the chemical composition similar to that of the duplex cast steel. As a result of the surfacing, the welds were obtained that had no welding imperfections with a smooth transition to the base material. In the test without the heat treatment, directly below the fusion line, we observe a ferrite band with a width of approximately 200 m without visible austenite areas. Some of the samples were then solution treated (1060°C). Both variants, without and after solution heat treatment, were subjected to testing. Significant changes in the microstructure of the joint were observed after the heat treatment process (heat affected zone and weld microstructure changes). In both areas, an increase in the austenite volume fraction after solution heat treatment was observed. Changes in the microhardness of the ferrite in the HAZ area directly below the fusion line were also observed.
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Archaeometallurgical investigations presented in this work focus on analysing the microstructure as well as mechanical properties of artefacts from the17th in form of findings performed from cast iron as well as copper casts. The presented research results extend the up-to-date knowledge and present the analysis of structural compounds found in the microstructure of the artefacts from the time dating back to the late Middle Ages in the region around Czestochowa, Poland. The tested samples were found in earth in the city centre under the present marketplace. The excavation works were carried out in summer in the year 2009, and have resulted in the excavation of artefacts in form of copper block of the weight of several kg. The excavation action was led by a group of Polish archaeologists collaborating with the local authorities. The performed pre-dating of this element determines the age of the artefacts as the 17th century AD. The excavations that have been taking place since 2007 have widened the knowledge of the former Czestochowa. Historians of this town have suggested, that the found weight and traces of metallurgical activity suggest that the exposed walls were an urban weight. The weight is visible on the 18th century iconography. What was find on the Old Market indicates that there was a lush economic life before the Swedish invasion in this part of Poland. Some buildings lost their functions or were changed, others died in fires, but new places developed. To describe the microstructure, with its structural components, research was done using microscopy techniques, both of the light as well as electron microscopy (SEM), also chemical composition analysis was carried out using the EDS technique, as well as tool for phase analysis were applied in form of X-Ray Diffraction (qualitative analysis), especially for the reason to describe the phases present in the excavated material. This research will help to obtain new information in order to investigate further archaeometallurgical artefacts, extending the knowledge about middle age metallic materials its usage and manufacturing.
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Detailed studies on the effects of pulsed laser interference heating on surface characteristics and subsurface microstructure of amorphous Fe80Si11B9 alloy are reported. Laser interference heating, with relatively low pulsed laser energy (90 and 120 mJ), but with a variable number (from 50-500) of consecutive laser pulses permitted to get energy accumulation in heated areas. Such treatment allowed to form two- Dimensional micro-islands of laser-affected material periodically distributed in amorphous matrix. The crystallization process of amorphous FeSiB ribbons was studied by means of scanning and transmission electron microscopy. Detailed microstructural examination showed that the use of laser beam, resulted in development of nanostructure in the heated areas of the amorphous ribbon. The generation of nanocrystalline seed islands created by pulsed laser interference was observed. This key result may evidently give new knowledge concerning the differences in microstructure formed during the conventional and lased induced crystallization the amorphous alloys. Further experiments are needed to clarify the effect of pulsed laser interference crystallization on magnetic properties of these alloys.
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The paper presents the impact of biodegradable material - polycaprolactone (PCL) on selected properties of moulding sands. A self-hardening moulding sands with phenol-furfuryl resin, which is widely used in foundry practice, and an environmentally friendly self-hardening moulding sand with hydrated sodium silicate where chosen for testing. The purpose of the new additive in the case of synthetic resin moulding sands is to reduce their harmfulness to the environment and to increase their “elasticity” at ambient temperature. In the case of moulding sands with environmentally friendly hydrated sodium silicate binder, the task of the new additive is to increase the elasticity of the tested samples while preserving their ecological character. Studies have shown that the use of 5% PCL in moulding sand increases their flexibility at ambient temperature, both with organic and inorganic binders. The influence of the new additive on the deformation of the moulding sands at elevated temperatures has also been demonstrated.
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The paper presents results of a study on the effect of the flux density of heat carried away for the remelting area to substrate in the course of surface remelting with concentrated heat stream on values of structural parameters λ1D and λ2D of α(Al) phase dendrites in C355 alloy. The remeltings were made with the use of GTAW method, at arc current intensity I = 200 A and concentrated heat stream scanning speed vs = 200, 400, 600, and 800 mm/min. The used protective gas was argon supplied at rate of 20 l/min. It has been found that the increase of the rate of scanning with concentrated heat stream results in a change of the remelting-substrate separation surface shape consisting in reduction of the remelting width and depth. This increases the value of the flux density of heat transmitted from the remelting area to substrate which in turn acts in favor of reduction of structural parameters λ1D and λ2D characterizing α(Al) phase dendrites in C355 alloy.
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The multiple direct remelting of composites based on the A359 alloy reinforced with 20% of Al2O3 particles was performed. The results of both gravity casting and squeeze casting were examined in terms of the obtained microstructure and mechanical characteristics. In microstructure examinations, the combinatorial method based on phase quanta theory was used. In mechanical tests, the modified low cycle fatigue method (MLCF) was applied. The effects obtained after both gravity casting and squeeze casting were compared. It was noted that both characteristics were gradually deteriorating up to the tenth remelting. The main cause was the occurrence of shrinkage porosity after the gravity casting. Much better results were obtained applying the squeeze casting process. The results of microstructure examinations and fatigue tests enabled drawing the conclusion that the A359 alloy reinforced with Al2O3 particles can confer a much better fatigue life behavior to the resulting composite than the A359 alloy without the reinforcement. At the same time, comparing these results with the results of the previous own research carried out on the composites based also on the A359 alloy but reinforced in the whole volume with SiC particles, it has been concluded that both types of the composites can be subjected to multiple remelting without any significant deterioration of the structural and mechanical characteristics. The concepts and advantages of using the combinatorial and MLCF methods in materials research were also presented
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In this study, the modification mechanism and growth process of Al3(Sc, Zr) particles in as-cast Al-Si-Mg-Cu based alloy with addition of Sc and Zr were systematically investigated. It was found that 0.57 wt-%Sc addition caused a significant refinement in the average grain size of the investigated alloy, which brought about a remarkable transformation in as-cast microstructure, from thick dendritic shape to fine equiaxed structure. A large amount of primary Al3(Sc, Zr) particles with the dimension of around 5-6 μm were also observed within the equiaxed grain. Due to the identical orientation and similar crystal structure between primary Al3(Sc, Zr) particles and α-Al matrix, the primary particles always served as heterogeneous nucleus for the α-Al matrix. In addition, these cusped cubic primary Al3(Sc, Zr) particles showed triangle, star, rhomboid morphologies are generated from sectioning the particle in (111), (100) and (110) planes, respectively. Particularly, the typical eutectic structure which contained odd number-layer (Al3(Sc, Zr)+α-Al+  +Al3(Sc, Zr)) was observed within the investigated particles.
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The paper concerns the processes connected with the formation of chromium white cast iron microstructure. The influence of titanium and strontium on the alloy crystallization has been described using TDA method and EDS analysis. Conducted experiments allowed the determination of the selected additions influence on the microstructure of examined alloys. TDA analysis enabled indication of the characteristic temperatures of thermal effects for samples with strontium and titanium and the comparison of results for the reference sample without additions. The results of TDA test also included the analysis of the temperature first derivative values, which presented interesting differences as well. The scanning microscopy observation clearly indicated the difference between the effect of strontium and titanium on the alloy microstructure. The EDS analysis helped to identify the chemical composition of the evolving phases and confirmed the strontium presence in the eutectic. Experimental results allowed to draw reliable conclusions about the effect of applied additions on the crystallization and microstructure of chromium cast iron.
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In sand casting, Fused Deposition Modeling (FDM) printing by using Poly Lactic Acid (PLA) filament is one of the innovative foundry technologies being adopted to substitute traditional pattern making. Several literatures have reported the influence of process parameters such as raster angle and print speed on some mechanical properties of FDM-printed, PLA-prototypes used in other applications. This study investigated the effects of interior fill, top solid layer, and layer height on the compressive strength of rapid patterns for sand casting application. Different values of the process parameters were used to print the pre-defined samples of the PLA-specimens and a compression test was performed on them. The coupled effects of the process parameters on compressive strength were investigated and the optimum values were determined. Interior fill of 36%, layer height of 0.21 mm and top solid layer of 4 were found to produce a FDM-printed, PLApattern that sustained a compaction pressure of 0.61 MPa. A simulation analysis with ANSYS® to compare failure modes of both experiment and model shows a similarity of buckling failure that occurred close to the base of each specimen.
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The publication presents the comparison of selected refining methods (gaseous and/or flux) based on mechanical properties of the obtained secondary silumin EN AC-AlSi7Mg0.3 (in accordance to the European Standard PN-EN 1706:2011). The point of reference was a similar primary alloy produced using pure batch materials. The mechanical properties measured in room temperature were used to calculate the materials quality index. The research showed, that properly carried out refinement process of secondary (recycled) alloys can bring their quality indexes close to those of their primary materials. The goal was to assess the efficiency of selected refining methods when applied to the examined group of casting silumins, by measuring the basic mechanical properties (in room temperature) before and after refining. The practical aspect was to choose an effective (ecologically, technologically and economically) method of refining of secondary EN AC-AlSi7Mg0.3 alloy used to cast car rims for JN METAL company in Ostowiec Świętokrzyski (Poland).
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This paper deals with numerical and analytical modelling of a diamond or silicon particle embedded in a metallic matrix. The numerical model of an elastic particle in a metallic matrix was created using the Abaqus software. Truncated octahedron-shaped and spherical-shaped diamond particles were considered. The numerical analysis involved determining the effect of temperature on the elastic and plastic parameters of the matrix material. The analytical model was developed for a spherical particle in a metallic matrix. The comparison of the numerical results with the analytical data indicates that the mechanical parameters responsible for the retention of diamond particles in a metal matrix are: the elastic energy of the particle, the elastic energy of the matrix and the radius of the plastic zone around the particle. An Al-based alloy containing 5% of Si and 2% of Cu was selected to study the mechanical behaviour of silicon precipitates embedded in the aluminium matrix. The model proposed to describe an elastic particle in a metallic matrix can be used to analyze other materials with inclusions or precipitates.
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In order to study the effects of various gating systems on the casting of a complex aluminum alloyed multi-way valve body, both software simulation analysis and optimization were carried out. Following, the aluminum alloyed multi-way valve body was cast to check the pouring of the aluminum alloy valve body. The computer simulation results demonstrated that compared to the single side casting mode, the casting method of both sides of the gating system would reduce the filling of the external gas, while the air contact time would be lower. Adversely, due to the pouring on both sides, the melt cannot reach at the same time, leading to the liquid metal speed into the cavity to differ, which affected the liquid metal filling stability. The riser unreasonable setting led to the solidification time extension, resulting in a high amount of casting defects during solidification. Also, both gating systems led the entire casting inconsequential solidification. To overcome the latter problems, a straight gate was set at the middle pouring and the horizontal gate diversion occurred on both sides of pouring, which could provide better casting results for the aluminum alloyed multi-valve body.
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Iron is presented as an impurity in Al-Si alloys and occurs in the form of the β-Al5FeSi phase formations. The presence of iron and other elements in the alloy causes the formation of large intermetallic phases. Due to the high brittleness of this phase, it reduces the mechanical properties and increases the porosity. Manganese is used to inhibit the formation of this detrimental phase. It changes the morphology of the phase to polyhedral crystals, skeletal formations, or Chinese script. The present article deals with the influence of various amounts of manganese (0.1; 0.2; 0.4; 0.6 wt. %) on the formation of iron-based intermetallic phases in the AlSi7Mg0.3 alloy with different levels of iron content (0.4; 0.8, 1.2 wt. %). The increase of iron content in each alloy caused the creation of more intermetallic compounds and this effect has been more significant with higher concentrations of manganese. In alloys where the amount of 1.2 wt. % iron is present, the shape of eutectic silicon grain changes from angular to short needle type.
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The article presents results of studies of silicon – molybdenum cast iron (4.42% Si, 2.59% Mo and 2.48% C wt.-%) crystallization process. Metallographic analysis was carried out using SEM-scanning electron microscopy with the EDS system. In order to determine the phase composition, X-ray diffraction studies were performed. Thermo-Calc, a computer simulation program, was used to simulate the crystallization process. . The obtained data allowed to describe the effect of some elements on the crystallization process. The silicon phase of MnSi could not be identified during metallographic studies. Also, computer simulation of the crystallization process did not answer the question at which point the silicon phase of MnSi crystallizes in the tested alloy. Therefore, not all results obtained were linked to the registered crystallization process (TDA process). The EDS analysis revealed an unusual distribution of molybdenum in the microstructure of the sample, where it is clearly visible that the area enriched with this element is also the separation of spheroidal graphite. The possibility of occurrence of Mo-rich micro-areas found in graphite is considered. The case is debatable and difficult to resolve at this stage. Perhaps, at such a high concentration of molybdenum (2.59% Mo) in the alloy, conditions are created for simultaneously crystallization of graphite and molybdenum phases.
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The study presents the results of the application of a statistical analysis for the evaluation of the effect of high-melting additions introduced into a pressure cast Al-Si alloy on the obtained level of its proof stress Rp0.2. The base Al-Si alloy used for the tests was a typical alloy used for pressure casting grade EN AC-46000. The base alloy was enriched with high-melting additions, such as: Cr, Mo, V and W. The additions were introduced into the base Al-Si alloy in all the possible combinations. The content of the particular high-melting addition in the Al-Si alloy was within the scope of 0.05 to 0.50%. The investigations were performed on both the base alloy and alloy with the high-melting element additions. Within the implementation of the studies, the values of Rp0.2 were determined for all the considered chemical compositions of the Al-Si alloy. A database was created for the statistical analysis, containing the independent variables (chemical composition data) and dependent variables (examined Rp0.2 values). The performed statistical analysis aimed at determining whether the examined high-melting additions had a significant effect on the level of Rp0.2 of the Al-Si alloy as well as optimizing their contents in order to obtain the highest values of the Al-Si alloy's proof stress Rp0.2. The analyses showed that each considered high-melting addition introduced into the Al-Si alloy in a proper amount can cause an increase of the proof stress Rp0.2 of the alloy, and the optimal content of each examined high-melting addition in respect of the highest obtained value of Rp0.2 equals 0.05%.
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Image analysis allows to acquire a number of valuable quantitative informations on the observed structure and make appropriate conclusions. So far, a large part of analyzed images came only from light microscopes, where it was a possibility of accurately distinguish the different phases on the plane. However, the problem happened in the case of the observation of images obtained by scanning electron microscopy. In this case, the presence of various shades of gray, and the spaciousness of the image attained. To perform the analysis the matrix images of the ausferritic ductile iron were used. Full analysis was carried out using the computer program MicroMeter 1.03. Results obtained in the analysis were related directly to the results from X-ray diffraction. Obtained as a result of the analysis were related directly to the results from X-ray diffractometer. The following technique has weaknesses, including the misinterpretation by the operator microscope or program. After all, it was possible to obtain similar results to the result that has been obtained from X-ray diffractometer.
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In cast iron foundries, used ferromagnetic batch materials can be transported and loaded into the furnace by lifting magnet. The precision of these operations by using electromagnetic grippers depends primarily on the variation in the mass of the batch material pieces. The article presents the characteristics of size of the batch materials used in the selected iron foundry. The obtained ranges mass values of individual pig iron ingots have been presented. It has been found that the mass of individual pig iron ingot may differ ± 25% from the declared by producer. The mass range of individual pieces of crushed or uncrushed return scrap was examined. Some pieces of uncrushed scrap have the mass more than three times the average weight of pieces of this scrap. Characteristics of the lifting capacity of these materials by a lifting magnet suspended to the crane was determined. Analysis of the obtained results indicates that for materials with less diversified mass of individual ferromagnetic pieces it is possible to use a gripper to weight a bigger portion with the same control setting. It was also found that there is a significant dispersion for a given gripper control, especially for materials with a wide range of individual pieces mass changes.
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The influence of a shape of graphite precipitates in cast iron on the thermal shock resistance of the alloy was initially determined. Investigations included the nodular cast iron and the vermicular one, as well as the cast iron containing flake graphite. The thermal shock resistance was examined at a special laboratory stand which allowed for multiple heating and cooling of specimens within the presumed temperature range. The specimens were inductively heated and then cooled in water of constant temperature of about 30°C. There were used flat specimens 70 mm long, 5 mm thick in the middle part, and tapering like a wedge over a distance of 15 mm towards both ends. The total length of cracks generated on the test surfaces of the wedge-shaped parts of specimens was measured as a characteristic value inversely proportional to the thermal shock resistance of a material. The specimens heated up to 500°C were subjected to 2000 test cycles of alternate heating and cooling, while the specimens heated up to 600°C underwent 1000 such cycles. It was found that as the heating temperature rose within the 500-600°C range, the thermal shock resistance decreased for all examined types of cast iron. The research study proved that the nodular cast iron exhibited the best thermal shock resistance, the vermicular cast iron got somewhat lower results, while the lowest thermal shock resistance was exhibited by grey cast iron containing flake graphite.
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In this work, the effect of the microstructure on corrosion behavior of selected Mg- and Al-based as cast alloys, was evaluated. The electrochemical examinations were carried out, and then a morphology of corrosion products formed due to local polarization on materials surface, was analyzed. It was documented that the presence of Mg2Si phase plays an important role in the corrosion course of Mg-based alloy. A selective etching was observed in sites of Mg2Si precipitates having “Chinese script”- like morphology. Analogous situation was found for Al-based alloy, where the key role was played by cathodic θ-CuAl2 phase.
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This article presents results of studies on multicriteria optimisation in the decopperisation process of flash smelting slags coming from the process of decopperisation at the "Głogów II" Copper Smelter. Measurements of viscosity were conducted using a high-temperature viscometer manufactured by Brookfield company. An addition in the form of calcium fluoride has an advantageous influence on decreasing the liquidus temperature of slag, and the effect of decreasing viscosity at the participation of calcium fluoride is significant. A motivation to conduct studies on viscosity of decopperised slags is an optimisation of the process of decopperisation at an improvement of this process parameters, i.e. the time of melt per one production cycle and consumption of electric power in the whole process. The efficiency of optimisation of the process course depends not only on an accepted criterion of the quality of controlling, a type of technological parameters, but also, to large extent, on characteristics and features of these parameters. CaCO3 currently added to the process of decopperisation efficiently decreases viscosity of flash slag, at the same time has influence on an increase of the yield of copper in alloy, but on the other hand, it increases the mass of slag, artificially under representing concentration of this metal. The article is completed with a conclusion of discussed issues, stating that a search for a new technological addition is still necessary,
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This paper presents matters related to production of ceramic and cast iron composite. The composite was made with the use of a foam structured ceramic insert. The tests included measuring of hardness, impact strength and resistance to abrasive wear of the composite produced. On the basis of obtaining results was stated that the use of foamed ceramic filters provides good conditions of filling a ceramic framework with molten grey or chromium cast iron. The growth of hardness of the ceramic- grey cast iron composite is ca. 60% as compared to the grey cast iron hardness. The growth of hardness of the ceramic- chromium cast iron composite is slight and does not exceed 5 % in comparison to the chromium cast iron. Introduction of the ceramic inserts deteriorates the cast iron impact strength by ca. 20 - 30 %. The use of ceramic inserts increases the resistance to abrasive wear in case of grey cast iron by ca. 13% and in case of the chromium cast iron by ca. 10 %.
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The paper refers to earlier publications of the author, on identification of properties of thermomechanical, chemically hardened core/mold sands. In that earlier period, first version of the original DMA apparatus, produced by a Polish company Multiserw-Morek, was used. The Hot Distortion (HD) study results, published by the author in 2008, referred to phenomena accompanying a thermal shock in real conditions of thermal interaction of a liquid alloy on a mold, in reference to a shock possible to obtain in laboratory conditions, without use of liquid alloy as a heat source, with analysis of solutions applied in the DMA apparatus. This paper presents author’s observations on testing a new, innovative version of the LRu-DMA apparatus, containing a module allowing the Hot Distortion (HD) study. Temperature of specimens achieved in the case of the gas burner heating reaches values definitely above 800°C on the heated side and 610°C on the other side. Using an electric radiator, with maximal temperature of 900°C allows obtaining temperatures in between 225-300°C.
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First part of the article describes how we can by change of gating system achieve better homogeneity of product made by investment casting. Turbine engine flap was made by investment casting technology – lost wax casting. The casting process was realised in vacuum. The initial conditions (with critical occurrence of porosity) was simulated in ProCAST software. Numerical simulation can clarify during analysis of melt turbulent flow in gate system responsible for creation of entrained oxide films. After initial results and conclusions, the new gating system was created with subsequent turbulence analysis. The new design of gating system support direct flow of metal and a decrease of porosity values in observed areas was achieved. Samples taken from a casting produced with use of newly designed gating system was processed and prepared for metallography. The second part of article deals with identification of structural components in used alloy - Inconel 718. The Ni – base superalloys, which are combined unique physical and mechanical properties, are used in aircraft industry for production of aero engine most stressed parts, as are turbine blades.
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This paper considers the assessment of attenuation in aluminium alloys castings and in cast iron prepared by gravity casting method and by casting under pressure. The issue of ultrasound attenuation is important in setting the conditions of non-destructive (NDT) testing, especially in casted materials. The characteristics of the ultrasonic technique and ultrasonic attenuation and the calculation of the attenuation and the velocity of ultrasound are presented in the theoretical part of this paper. For experimental measurements, cylindrical castings from AlSi alloy (a hypoeutectic alloy with a silicon content of about 7% - AlSi7 and a eutectic alloy with a silicon content of about 12% - AlSi12) and from grey and ductile cast iron were made. The ultrasonic records of the casting control, the calculation of ultrasound attenuation for individual samples are listed and described in the experimental part. The evaluation of measurements and comparison of calculated ultrasound attenuation is at the end of this article.
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This article deal with non-conventional methods to affect the crystallization of Al-alloys by the application of electromagnetic field. The application of electromagnetic field is not technically complicated, it does not require mechanical contact with the melt, and the scale of the crystallization influence is not dependent on the thickness of the casting. Two experimental materials were used: AlSi10MgMn and AlSi8Cu2Mn and two values of electromagnetic induction: B = 0.1 T a B = 0.2 T. The best results for alloy AlSi10MgMn were achieved by application of electromagnetic field with induction B = 0.2 T; during this experiment the best mechanical properties were achieved - the biggest increase of mechanical properties was recorded. The best results for alloy AlSi8Cu2Mn were achieved by combination of electromagnetic field with induction B = 0.1 T and modification by 0.05 wt. % Sr. In this case we don´t recommend to use electromagnetic field with induction B = 0.2 T; because of deposition of coarse grains and decreasing of mechanical properties.
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In the research, relationships between matrix structure and hardness of high-quality Ni-Mn-Cu cast iron containing nodular graphite and nickel equivalent value were determined. Nickel equivalent values were dependent on chemical composition and differences between them resulted mostly from nickel concentration in individual alloys. Chemical compositions of the alloys were selected to obtain, in raw condition, austenitic and austenitic-martensitic cast iron. Next, stability of matrix of raw castings was determined by dilatometric tests. The results made it possible to determine influence of nickel equivalent on martensite transformation start and finish temperatures.
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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.
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The results of estimation of home scrap addition in charge influence on durability and wear of casting instrumentation life in the highpressure casting technology using the hot chamber machine of alloy of AZ91 are presented. The wear of the following elements of the casting instrumentation so-called "casting set" as: syphon, plunger, sliding-rings, nozzle and injection moulding nozzle was estimated. A wear was estimated quantitative by registering the number of mould injections for different charges to the moment of element damage supervision. A damage had to be at such level that liquidated an element from further exploitation and necessary was an exchange on new or regeneration. In a final result allowed it the detailed determination of durability of the applied rigging elements in dependence on the type of the applied type of melt. It is noticed, that together with the increase of home-scrap participation in the charge wear of pressure machine instrumentation elements increases.
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Use of welding technology for the repair of steel castings is particularly common in two areas. These include weld surfacing of protrusions that remained incomplete after casting, or filling the surface defects (cavities). These defects are more common for steel casting than for graphite cast iron, due to the lower fluidity of steel. This article describes a suitable technological process of repairing the defects on the casting using the welding technology. A specimen produced for this purpose was prepared by carving a groove into a cast steel plate 20 GL, which was then filled with a weld metal using MAG (135) technology. The following evaluation of the basic characteristics of the repaired site point to the suitability of the selected technological parameters of the repair procedure. Metallographic evaluation was carried out, further evaluation of mechanical properties by tensile test, bend test and Vickers hardness test. The proposed methodology for the evaluation repair of foundry defects in steel castings also meets the requirements for the approval of welding procedures in accordance with the relevant valid legislation.
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The paper presents the research results of the influence of the precipitation hardening on hardness and microstructure of selected Al-Si and Al-Cu alloys obtained as 30 mm ingots in a horizontal continuous casting process. The ingots were heat treated in process of precipitation hardening i.e. supersaturation with subsequent accelerated or natural ageing. Moreover in the range of the study it has been carried out investigations of chemical constitution, microscopic metallographic with use of scanning electron microscope with EDS analysis system, and hardness measurements using the Brinell method. On basis of obtained results it has been concluded that the chemical constitution of the investigated alloys enables to classify them into Al alloys for the plastic deformation as EN AW-AlSi2Mn (alternatively cast alloy EN AC-AlSi2MgTi) and as EN AW-AlCu4MgSi (alternatively cast alloy EN AC-AlCu4MgTi) grades. Moreover in result of applied precipitation hardening has resulted in the precipitation from a supersaturated solid solution of dispersive particles of secondary phases rich in alloying element i.e. Si and Cu respectively. In consequence it has been obtained increase in hardness in case of AlSi2Mn alloy by approximately 30% and in case of AlCu4MgSi alloy by approximately 20% in comparison to the as-cast state of continuous ingots.
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This article discusses the issue of the preparation of the foundry moulds with the use of an industrial robot. The methodology is presented for the determination of the process capacity index for placing inserts with flat and cylindrical faces. On the basis of the relationships developed, the process capability indices were determined at various points in the workspace, which are characterised by different values of the repeatability positioning error. It was shown that the value of the process capacity index can be increased by the selection of a suitable location for the process of placing the inserts in the workspace. It should also be noted that the value of the process's capability index depends on the selection of the place in the robot workspace where the process is carried out. Implementation of the joining process at an analysed point in the robot workspace leads to an increase of the process capability index MCp for inserts with flat faces up to 1.1 (+4.5%) and for inserts with cylindrical faces up to 1.3. This results in an increase of 13% to a level corresponding to the global standard for process reliability (MCp = 1.33).
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The results of model investigations of the influence of the blowing process selected parameters on the distribution of the compaction of the core made by the blowing method, are presented in the hereby paper. These parameters were: shooting pressure, shooting hole diameter, amount and distribution of deaerating holes. Investigations were performed using the horizontal core box of the cuboidal cavity and the same core box into which inner inserts were introduced. These inserts were dividing the primary volume into three sectors differing in their direction, introduction conditions and the character of the core sand flow. As the compaction measure the apparent sand density was assumed. The density was determined in five measuring points in case of uniform cores, and in three measuring points in case of cores obtained in the core box with three separated sectors. The apparent density of the compacted core sand in the core box cavity was determined on the basis of the measurements of masses and volumes of samples cut-out from the determined core places by means of the measuring probe. Investigations were performed at three values of the working pressure equal 0.4, 0.5 and 0.6MPa for two diameters of the shooting hole: 10 and 20 mm. During tests the core box deaeration, controlled by an activisation of the determined number of deaerating vents placed in the core box, was also subjected to changes.
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A method for manufacturing of Al-Si alloy (EN AC-44200) matrix composite materials reinforced with MAX type phases in Ti-Al-C systems was developed. The MAX phases were synthesized using the Self-propagating High-Temperature Synthesis (SHS) method in its microwave assisted mode to allow Ti2AlC and Ti3AlC2 to be created in the form of spatial structures with open porosity. Obtained structures were subjected to the squeeze casting infiltration in order to create a composite material. Microstructures of the produced materials were observed by the means of optical and SEM microscopies. The applied infiltration process allows forming of homogeneous materials with a negligible residual porosity. The obtained composite materials possess no visible defects or discontinuities in the structure, which could fundamentally deteriorate their performance and mechanical properties. The produced composites, together with the reference sample of a sole matrix material, were subjected to mechanical properties tests: nanohardness or hardness (HV) and instrumental modulus of longitudinal elasticity (EIT).
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The study involved using the liquid-solid compound casting process to fabricate a lightweight ZE41/AlSi12 bimetallic material. ZE41 melt heated to 660 oC was poured onto a solid AlSi12 insert placed in a steel mold. The mold with the insert inside was preheated to 300 oC. The microstructure of the bonding zone between the alloys was examined using optical microscopy and scanning electron microscopy. The chemical composition was determined through linear and point analyses with an energy-dispersive X-ray spectroscope (EDS). The bonding zone between the magnesium and aluminum alloys was about 250 μm thick. The results indicate that the microstructure of the bonding zone changes throughout its thickness. The structural constituents of the bonding zone are: a thin layer of a solid solution of Al and Zn in Mg and particles of Mg-Zn-RE intermetallic phases (adjacent to the ZE41 alloy), a eutectic region (Mg17(Al,Zn)12 intermetallic phase and a solid solution of Al and Zn in Mg), a thin region containing fine, white particles, probably Al-RE intermetallic phases, a region with Mg2Si particles distributed over the eutectic matrix, and a region with Mg2Si particles distributed over the Mg-Al intermetallic phases matrix (adjacent to the AlSi12 alloy). The microstructural analysis performed in the length direction reveals that, for the process parameters tested, the bonding zone forming between the alloys was continuous. Low porosity was observed locally near the ZE41 alloy. The shear strength of the AZ91/AlSi17 joint varied from 51.3 to 56.1 MPa.
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The paper presents relationships between the degree of structure fineness and feeding quality of the Al – 20 wt.% Zn (Al-20 Zn) alloy cast into a mould made from sand containing silica quartz as a matrix and bentonite as a binder, and its damping coefficient of the ultrasound wave at frequency of 1 MHz. The structure of the examined alloy was grain refined by the addition of the refining Al-3 wt.% Ti – 0.15 wt.%C (TiCAl) master alloy. The macrostructure analysis of the initial alloy without the addition of Ti and the alloy doped with 50-100 ppm Ti as well as results of damping experiments showed that the structure of the modified alloy is significantly refined. At the same time, its damping coefficient decreases by about 20-25%; however, it still belongs to the so called high-damping alloys. Additionally, it was found that despite of using high purity metals Al and Zn (minimum 99,99% purity), differences in the damping coefficient for samples cut from upper and bottom parts of the vertically cast rolls were observed. These differences are connected with the insufficient feeding process leading to shrinkage porosity as well as gases present in metal charges which are responsible for bubbles of gas-porosity.
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Inconel 713C is a nickel-based casting alloy characterised by improved heat and creep resistance [1]. It is used e.g. in aircraft engine components, mainly in the form of precision castings. Precision casting enables very good reproduction of complex shapes. However, due to major differences in casting wall thickness and the resultant differences in rigidity, defects can form in precision castings. The most common defects in precision castings are shrinkage porosities and microcracks. Inconel 713C is considered to be a difficult-to-weld or even non-weldable alloy. However, the need to repair precision castings requires attempts to develop technologies for their remelting and pad welding which could be used in industrial practice. This article presents the results of tests consisting in TIG pad welding of defects identified in precision castings intended for the aircraft industry. It was found that the main reason behind failed attempts at repairing precision castings by welding technologies was hot cracking in the fusion zone. Such cracks form as a result of the partial melting of intercrystalline regions along the fusion line. The deformations occurring during the crystallization of the melting-affected zone (fusion zone + partially melted zone + heat affected zone) or pad weld lead to the rupture of the intercrystalline liquid film. Hot cracks form within the so-called high-temperature brittleness range (HTBR) of the alloy. Another type of cracks that was identified were ductility dip cracks (DDC), whose formation is related to the partial melting of carbides.
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The article deals with the influence of chemical composition of martensitic stainless steel for castings GXCrNi13-4 (the 1.4317 material) on mechanical properties and structure of as cast steel after heat treatment. Properties of these martensitic stainless steel are heavily influenced by chemical composition and structure of the material after heat treatment. Structure of these steels after quenching is formed with martensite and residual austenite. When tempering the steel the carbon content in martensite is reduced and gently deposited carbides occur. The way of heat treatment has a major impact on structure of martensitic steels with low carbon content and thus on strength, hardness and elongation to fracture of these steels. Chemical composition of the melt has been treated to the desired composition of the lower, middle and upper bounds of the nickel content in the steel within the limits allowed by the standard. Test blocks were gradually cast from the melt. The influence of the nickel equivalent value on structure and properties of the 1.4317 steel was determined from results of mechanical tests.
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Redakcja

CHIEF EDITORS
Editor
J. Szajnar
Deputy Editor
J. Jezierski

SUBJECT EDITORS
Theoretical Aspects of Casting Processes
K. Eigenfeld – Freiberg, Germany
E. Guzik – Kraków, Poland
T. G. Mathia - Lyon, France
W. Wołczyński – Kraków, Poland
Innovative Foundry Technologies and Materials
T. Elbel – Ostrava, Czech Republic
Z. Ignaszak – Poznań, Poland
O. P. Pandey – Punjab, India
A. Pereira - Vigo, Spain
Foundry Processes Computer Aiding
B. Mochnacki – Częstochowa, Poland
J. Roučka – Brno, Czech Republic
J.S. Suchy – Kraków, Poland
Mechanization, Automation and Robotics in Foundry
J. Bast – Freiberg, Germany
R. Wrona – Kraków, Poland
Transport Systems in Foundry
J. Dańko – Kraków, Poland
Z. Li – Shijiazhuang, China
Castings Quality Management
D. Bolibruchova– Żilina, Slovak Republic
J. D. B. de Mello - Santa Monica, Brazil
M. Perzyk – Warszawa, Poland
Environment Protection
M. Holtzer – Kraków, Poland
H. Polzin – Freiberg, Germany
J. Sobczak – Kraków, Poland
I. Volchok – Zaporizhzhya, Ukraine

EDITORIAL ADVISORY BOARD
J. Braszczyński – Częstochowa, Poland
B. K. Dhindaw – Rupnagar, India
L. A. Dobrzański – Gliwice, Poland
W. A. Hufenbach – Dresden, Germany
P. Jelínek – Ostrava, Czech Republic
L. Jeziorski – Częstochowa, Poland
J. Lacaze – Toulouse, France
V. L. Naydek – Kiev, Ukraine
A. Passerone – Genova, Italy
I. Riposan – Bucharest, Romania
F. Romankiewicz – Zielona Góra, Poland
A. Sládek – Żilina, Slovak Republic

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M. Azadi – Tehran, Iran
Y. Babaskin – Kiev, Ukraine
K. Bako – Miskolc, Hungary
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L. Bechný – Zilina, Slovak Republic
V. Bednarova - Ostrava, Czech Republic
F. Bińczyk – Katowice, Poland
A. Bokota – Częstochowa, Poland
G.P. Borisov – Kiev, Ukraine
A. Bydałek – Kraków, Poland
C. H. Cáceres – Brisbane, Australia
J. Čech – Brno, Czech Republic
L. Q. Chen – Shenyang, China
A. Chojecki – Kraków, Poland
M. Cholewa – Gliwice, Poland
I. A. Dibrov – Moscow, Russia
D. Dispinar – Istanbul, Turkey
S. M. Dobosz – Kraków, Poland
V. I. Dubodelov – Kiev, Ukraine
A. Fedoryszyn – Krakow, Poland
J. Głownia – Kraków, Poland
K. Granat – Wrocław, Poland
J. Hampl – Ostrava, Czech Republic
J. Helber – Düsseldorf, Germany
M. Hetmańczyk – Katowice, Poland
M. Horáček – Brno, Czech Republic
M. Kaczorowski – Warszawa, Poland
W. Kapturkiewicz – Kraków, Poland
R. Kawalla – Freiberg, Germany
Z. Konopka – Czestochowa, Poland
D. Kopyciński – Kraków, Poland
W. K. Krajewski – Kraków, Poland
Z. Libo – Beijing, China
P. Lichy – Ostrava, Czech Republic
Y. P. Lim – Setapak, Malaysia
T. Lipiński – Olsztyn, Poland
E. Majchrzak – Gliwice, Poland
A. Mityayev - Zaporizhzhya, Ukraine
M. Murgaš – Trnava, Slovak Republic
I. Nová – Liberec, Czech Republic
W. Orłowicz – Rzeszów, Poland
T. Pacyniak – Łódź, Poland
B. Piekarski – Szczecin, Poland
A. Rimmer – West Bromwich, United Kingdom
S. Samavedam – Hyderabad, India
P. Schumacher – Leoben, Austria
N. Sczygiol – Częstochowa, Poland
P. Skočovský – Żilina, Slovak Republic
M.S. Soiński – Częstochowa, Poland
J. Sokolowski – Ottawa, Kanada
K. V. Sudhakar – Butte, USA
B. G. Thomas - Champaign, USA
M. Trbižan – Ljubljana, Slovenia
J. Vuorinen – Tampere, Finland
E. Ziółkowski – Kraków, Poland
J. Zych – Kraków, Poland

ASSOCIATE EDITORS
D. Bartocha – Gliwice, Poland, - editorial secretary
J. Suchoń – Gliwice, Poland - editorial secretary
J. Szymszal – Katowice, Poland, Statistic Editor
A. Dulska – Gliwice, Poland
M. Kondracki – Gliwice, Poland
C. Borek –Chicago, USA, Language Editor

 

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