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Number of results: 196
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Abstract

An analysis has been carried out of the influence of annealing time at the preheating temperature of 650 °C on the change in hardness and alloy structure of lamellar graphite cast iron in the working as well as in the laboratory conditions. This preheat temperature is common during reclaiming welding of castings with complex shapes. The changes in unalloyed cast iron EN-GJL 200 to EN-GJL 300 according to ISO 1690 standard and cast iron with low amount of elements such as Sn, Cu, Cr, and Mo and their combinations were assessed. It was found that the cast iron of higher strength grades has better hardness and structural stability. Cast iron alloyed with chromium or its combinations has the highest stability. In unalloyed cast iron, a partial degradation of pearlite occurs; in alloyed cast iron the structural changes are not conclusive.
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Abstract

The paper presents the results of investigations concerning the influence of gray cast iron modification on free vibration frequency of the disc casting. Three different chemical composition melts of gray cast iron were prepared in induction furnace. During gravity casting 0.05% and 0.3% mass of the Inolate modifier was added on stream of metal for changing graphite flakes in castings. Sound signal vibration of cast iron sample was registered by means on microphone for free vibration frequency measurements. Decreasing of free vibration frequency of modified cast iron in comparison with non modified castings was observed. Higher contents of modifier causes more decreasing of free vibration frequency. Cast iron with smaller contents of carbon and silicon have higher free vibration frequency in comparison with eutectic composition cast iron. Hardness of examined cast iron is lower when the more modifier is added during modification process. Free frequency is smaller with smaller Brinell hardness of disc casting. It was concluded that control of free vibration frequency of disc castings by means of chemical composition and modification process can improved comfort and safety of working parts.
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Abstract

The paper presents the initial results of investigation concerning the abrasion resistance of cast iron with nodular, vermicular, or flake graphite. The nodular and vermicular cast iron specimens were cut out of test coupons of the IIb type with the wall thickness equal to 25 mm, while the specimens made of grey cast iron containing flake graphite were cut out either of special casts with 20 mm thick walls or of the original brake disk. The abrasion tests were carried out by means of the T-01M tribological unit working in the pin-on-disk configuration. The counterface specimens (i.e. the disks) were made of the JT6500 brand name friction material. Each specimen was abraded over a distance of 4000 m. The mass losses, both of the specimens and of the counterface disks, were determined by weighting. It was found that the least wear among the examined materials was exhibited by the nodular cast iron. In turn, the smallest abrasion resistance was found in vermicular cast iron and in cast iron containing flake graphite coming from the brake disk. However, while the three types of specimens (those taken from the nodular cast iron and from grey cast iron coming either from the special casts or from the brake disk) have almost purely pearlitic matrix (P95/Fe05), the vermicular cast iron matrix was composed of pearlite and ferrite occurring in the amounts of about 50% each (P50/Fe50). Additionally, it was found that the highest temperature at the cast iron/counterface disk contact point was reached during the tests held for the nodular cast iron, while the lowest one occurred for the case of specially cast grey iron.
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Abstract

In this paper results of microstructural observations for series of CuZn39Pb2 alloys produced from qualified scraps are presented. The individual alloy melts were differentiated in terms of thermal parameters of continuous casting as well as refining methods and modifications. Structural observations performed by SEM and TEM revealed formation of different types of intermetallic phases including “hard particles”. EDS results show that “hard particles” are enrich in silicon, phosphorus, iron, chromium and nickel elements. Additionally, formation of Al-Fe-Si and Al-Cr in alloy melts was observed as well. It was found that quantity and morphology of intermetallic phases strongly depends upon the chemical composition of raw materials, process parameters, modifiers and refining procedure applied during casting. It was observed that refining process results in very effective refinement of intermetallic phases, whereas modifiers, particularly carbon-based, results in formation of large particles in the microstructure.
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Abstract

This paper presents results of a research on the possibilities of applying 3D printed casting models for small production series as alternative to traditional tooling production on automated DisaMatch mould production lines. The main task was to verify and compare the dimensions of the 3D printed models before and after moulding process. The paper discusses main advantages and disadvantages of the 3D printing methods used like FDM (Fused Deposition Modeling)/FFF (Fused Filament Fabrication), SLA (stereolitography) and DPP (Daylight Polymer Printing). Measurement of casting model outside dimension change resulting from moulding sand friction on their surface was made with the use of GOM INSPECT software on the basis of 3D scans made with ATOS TripleScan optical scanner. Hardness of 3D printed models made of ABS, Z-ULTRAT, three different photopolymer resins (from FormLab and Liquid Crystal companies) was verified. The result of the research printed models usability for the foundry industry was presented.
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Abstract

The objective of the study reported in this paper was to determine the effect of structure on thermal power of cast-iron heat exchangers which in this case were furnace chambers constituting the main component of household fireplace-based heating systems and known commonly as fireplace inserts. For the purpose of relevant tests, plate-shaped castings were prepared of gray iron with flake graphite in pearlitic matrix (the material used to date typically for fireplace inserts) as well as similar castings of gray cast iron with vermicular graphite in pearlitic, ferritic-pearlitic, and ferritic matrix. For all the cast iron variants of different structures (graphite precipitate shapes and matrix type), calorimetric measurements were carried out consisting in determining the heat power which is quantity representing the rate of heat transfer to the ambient environment. It has been found that the value of the observed heat power was affected by both the shape of graphite precipitates and the type of alloy matrix. Higher thermal power values characterize plate castings of gray iron with vermicular graphite compared to plates cast of the flake graphite gray iron. In case of plates made of gray cast iron with vermicular graphite, the highest values of thermal power were observed for castings made of iron with ferritic matrix.
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Abstract

The paper consists the problem of developing a scientific toolkit allowing to predict the thermal state of the ingot during its formation in all elements of the casting and rolling complex, between the crystallizer of the continuous casting machine and exit from the furnace. As the toolkit for the decision making task the predictive mathematical model of the ingot temperature field is proposed. Displacement between the various elements of the CRC is accounted for by changing the boundary conditions. Mass-average enthalpy is proposed as a characteristic of ingot cross-section temperature state. The next methods of solving a number of important problems with the use of medium mass enthalpy are developed: determination of the necessary heat capacity of ingots after the continuous casting machine for direct rolling without heating; determination of the rational time of alignment of the temperature field of ingots having sufficient heat capacity for rolling after casting; determination of the total amount of heat (heat capacity) required to supply the metal for heating ingots that have insufficient amount of internal heat.
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Abstract

Results of a research on influence of chromium, molybdenum and aluminium on structure and selected mechanical properties of Ni-Mn-Cu cast iron in the as-cast and heat-treated conditions are presented. All raw castings showed austenitic matrix with relatively low hardness, making the material machinable. Additions of chromium and molybdenum resulted in higher inclination to hard spots. However, a small addition of aluminium slightly limited this tendency. Heat treatment consisting in soaking the castings at 500 °C for 4 h resulted in partial transformation of austenite to acicular, carbon-supersaturated ferrite, similar to the bainitic ferrite. A degree of this transformation depended not only on the nickel equivalent value (its lower value resulted in higher transformation degree), but also on concentrations of Cr and Mo (transformation degree increased with increasing total concentration of both elements). The castings with the highest hard spots degree showed the highest hardness, while hardness increase, caused by heat treatment, was the largest in the castings with the highest austenite transformation degree. Addition of Cr and Mo resulted in lower thermodynamic stability of austenite, so it appeared a favourable solution. For this reason, the castings containing the highest total amount of Cr and Mo with an addition of 0.4% Al (to reduce hard spots tendency) showed the highest tensile strength.
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Abstract

Ablation casting is a technological process in which the increased cooling rate causes microstructure refinement, resulting in improved mechanical properties of the final product. This technology is particularly suitable for the manufacture of castings with intricate shapes and thin walls. Currently, the ablation casting process is not used in the Polish industry. This article presents the results of strength tests carried out on moulding sands based on hydrated sodium silicate hardened in the Floster S technology, intended for ablation casting of the AlSi7Mg (AK7) aluminium alloy. When testing the bending and tensile strengths of sands, parameters such as binder and hardener content were taken into account. The sand mixtures were tested after 24h hardening at room temperature. The next stage of the study describes the course of the ablation casting process, starting with the manufacture of foundry mould from the selected moulding mixture and ending in tests carried out on the ready casting to check the surface quality, structure and mechanical properties. The results were compared with the parallel results obtained on a casting gravity poured into the sand mould and solidifying in a traditional way at ambient temperature.
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Abstract

Early Buddhism was a predominantly spiritual movement which should ideally culminate in Enlightenment. Yet, it was embedded in the specific social environment of ancient India which included a hereditary caste system. Using the Buddhist Pāli texts and non-Buddhist literature from up until the last centuries BCE the article examines the four main hereditary categories (vaṇṇa, jāti, gotta, and kula) and how Early Buddhism related to them. We conclude that the Buddha and Early Buddhism did not oppose but rather confirmed the hereditary systems in society as well as its designations within the monastic community. The Buddha hereby followed the customs of earlier ascetic movements and imposed no specific rules on the monastics to eradicate their former social identity.
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Abstract

Investment casting combined with the additive manufacturing technology enables production of the thin-walled elements, that are geometrically complex, precise and can be easy commercialized. This paper presents design of aluminium alloy honeycombs, which are characterized with light structure, internal parallel oriented channels and suitable stiffness. Based on 3D printed pattern the mould was prepared from standard ceramic material subjected subsequently to appropriate heat treatment. Into created mould cavity with intricate and susceptible structure molten AC 44200 aluminium alloy was poured under low pressure. Properly designed gating system and selected process parameters enabled to limit the shrinkage voids, porosities and misruns. Compression examination performed in two directions showed different mechanisms of cell deformation. Characteristic plateau region of stress-strain curves allowed to determine absorbed energy per unit volume, which was 485 or 402 J/mm3 depending on load direction. Elaborated technology will be applied for the production of honeycomb based elements designated for energy absorption capability.
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Abstract

Final quality of casts produced in a die casting process represents a correlation of setting of technological parameters of die casting cycle, properties of alloy, construction of a die and structure of gating and of bleeding systems. Suitable structure of a gating system with an appertaining bleeding system of the die can significantly influence mechanical and structural properties of a cast. The submitted paper focuses on influence of position of outfall of an gate into the cast on its selected quality properties. Layout of the test casts in the die was designed to provide filling of a shaping cavity by the melt with diverse character of flowing. Setting of input technological parameters during experiment remained on a constant level. The only variable was the position of the gate. Homogeneity represented by porosity f and ultimate strength Rm were selected to be the assessed representative quality properties of the cast. The tests of the influence upon monitored parameters were realized in two stages. The test gating system was primarily subjected to numerical tests with the utilization of a simulation program NovaFlow&Solid. Consequently, the results were verified by the experimental tests carried out with the physical casts produced during operation. It was proved that diverse placement of the gate in relation to the cast influences the mode of the melt flowing through the shaping cavity which is reflected in the porosity of the casts. The experimental test proved correlation of porosity f of the cast with its ultimate strength Rm. At the end of the paper, the interaction dependencies between the gate position, the mode of filling the die cavity, porosity f and ultimate strength Rm.
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Abstract

The mathematical model and numerical simulations of the solidification of a cylindrical shaped casting, which take into account the process of filling the mould cavity by liquid metal and feeding the casting through the riser during its solidification, are presented in the paper. Mutual dependence of thermal and flow phenomena were taken into account because have an essential influence on solidification process. The effect of the riser shape on the effectiveness of feeding of the solidifying casting was determined. In order to obtain the casting without shrinkage defects, an appropriate selection of riser shape was made, which is important for foundry practice. Numerical calculations of the solidification process of system consisting of the casting and the conical or cylindrical riser were carried out. The velocity fields have been obtained from the solution of momentum equations and continuity equation, while temperature fields from solving the equation of heat conductivity containing the convection term. Changes in thermo-physical parameters as a function of temperature were considered. The finite element method (FEM) was used to solve the problem.
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Abstract

Analysis of the use of the Russian materials (liquid glass and softening additives) has been made in accordance with the modern requirements for use in the technological processes of casting as binding materials in the production of large-sized steel railway casting. The reasons for poor knockout of liquid glass mixtures have been investigated. A complex action softening additive has been recommended for a better knocking-out ability. This solution provides a softening effect at the points of maximum formation of the liquid glass matrix strength in the processes of polymorphic transformation of the material under the influence of elevated temperatures as the result of filling the mold cavity by the melt. It has been shown that the use of additives of complex action leads to the decrease in the specific work of the knockout by four – seven times depending on the composition of the mixture and the design features of the casting. Experimental-industrial tests of the proposed method for softening the liquid glass mixtures have been made and the "Front Buffer Stop" casting has been made (for the rolling stock of locomotives and railway wagons). The tests confirmed the effectiveness and expediency of implementation of new liquid glass mixtures with softening additives in conditions of foundry enterprises.
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Abstract

This article proposes to use abrasive waterjet cutting (AWJ) for deflashing, deburring and similar finishing operations in casting. The basic requirements concerning the dimensional accuracy and surface texture of cast components are not met if visible surface flaws are detected. The experiments focused on the removal of external flash from elements made of EN-GJL-150 cast iron. The method employed for finishing was abrasive waterjet cutting. The tests were carried out using an APW 2010BB waterjet cutting machine. The form profiles before and after flash removal were determined with a Taylor Hobson PGI 1200 contact profiler. A Nikon AZ100 optical microscope was applied to observe and measure the changes in the flash height and width. The casting surface after finishing was smooth, without characteristic sharp, rough edges that occur in the cutting of objects with a considerable thickness. It should be emphasized that this method does not replace precise cutting operations. Yet, it can be successfully used to finish castings for which lower surface quality is required. An undoubted advantage of waterjet cutting is no effect of high temperature as is the case with plasma, laser or conventional cutting. This process is also easy to automate; one tool is needed to perform different finishing operations in order to obtain the desired dimensions, both internal and external.
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Abstract

An overview of the bibliography regarding the connection of knowledge about precious metal alloys and aspects of the use of computer aided technologies to the optimization of the jewelry casting processes is presented. An analysis of the usability of selected CAx systems was made: 1) for spatial design, called Rhinoceros 6 and 2) CAE system: NovaFlow & Solid (NF&S). The authors describe own research including data acquisition and evaluation of temperature variations during solidification of the selected Au-Ag-Cu alloy, with the identification of the phase transformations of this alloy. The intensity of heat exchange was changed (cooling of specimens under ambient temperature conditions – "normal" intensity and with the furnace – very slow cooling). The problem of completing the simulation database was pointed out and analyzed. Examples of simulations of casting selected jewelry (ring and signet) were given and compared with the result of the experiment realized in real conditions. It was confirmed that the optimization by combining experimental and simulation studies allows for the acquisition of new knowledge, and also facilitates the creation of new artistic designs of jewelry as well as performing the feasibility check, and then optimizing the chosen technology.
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Abstract

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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Abstract

Results of investigations of wear resistant of two species of cast steel were introduced in the article (low-alloyed and chromium cast steel) on the background of the standard material which was low alloy wear resistant steel about the trade name CREUSABRO ®8000. The investigations were executed with two methods: abrasive wears in the stream of loose particles (the stream of quartz sand) and abrasive wears particles fixed (abrasive paper with the silicon carbide). Comparing the results of investigations in the experiments was based about the counted wear index which characterizes the wears of the studied material in the relation to the standard material.
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Abstract

The article presents results of pitting corrosion studies of selected silicon cast irons. The range of studies included low, medium and high silicon cast iron. The amount of alloying addition (Si) in examined cast irons was between 5 to 25 %. Experimental melts of silicon cast irons [1-3] were conducted in Department of Foundry of Silesian University of Technology in Gliwice and pitting corrosion resistance tests were performed in Faculty of Biomedical Engineering in Department of Biomaterials and Medical Devices Engineering of Silesian University of Technology in Zabrze. In tests of corrosion resistance the potentiostat VoltaLab PGP201 was used. Results obtained in those research complement the knowledge about the corrosion resistance of iron alloys with carbon containing Si alloying addition above 17 % [4-6]. Obtained results were supplemented with metallographic examinations using scanning electron microscopy. The analysis of chemical composition for cast irons using Leco spectrometer was done and the content of alloying element (silicon) was also determined using the gravimetric method in the laboratory of the Institute of Welding in Gliwice. The compounds of microstructure were identify by X-ray diffraction.
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Abstract

The work presents the results of the experimental research concerning the impact of a heat treatment (toughening) of aluminum bronze CuAl10Fe4Ni4 on its mechanical properties. The conditions of the experiments and selected results are described. A detailed description of the effects of individual heat treatment conditions namely low and high temperature aging is also presented in the work.
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Abstract

The paper presents the issue of synthetic cast iron production in the electric induction furnace exclusively on the steel scrap base. Silicon carbide and synthetic graphite were used as carburizers. The carburizers were introduced with solid charge or added on the liquid metal surface. The chemical analysis of the produced cast iron, the carburization efficiency and microstructure features were presented in the paper. It was stated that ferrosilicon can be replaced by silicon carbide during the synthetic cast iron melting process. However, due to its chemical composition (30% C and 70% Si) which causes significant silicon content in iron increase, the carbon deficit can be partly compensated by the carburizer introduction. Moreover it was shown that the best carbon and silicon assimilation rate is obtained where the silicon carbide is being introduced together with solid charge. When it is thrown onto liquid alloy surface the efficiency of the process is almost two times less and the melting process lasts dozen minutes long. The microstructure of the cast iron produced with the silicon carbide shows more bulky graphite flakes than inside the microstructure of cast iron produced on the pig iron base.
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Abstract

The results of studies on the use of magnesium alloy in modern Tundish for production of vermicular graphite cast irons were described. This paper describes the results of using a low-magnesium ferrosilicon alloy for the production of vermicular graphite cast irons. The paper presents a vermicular (and nodular) graphite in different walled castings. The results of trials have shown that the magnesium Tundish process can produce high quality vermicular graphite irons under the specific industrial conditions of Foundries - Odlewnie Polskie S.A. in Starachowice. In this work describes too preliminary studies on the oxygen state in cast iron and their effect on graphite crystallization.
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Abstract

Contribution gives an overview of knowledge about the method of centrifugal casting with orientate on Tekcast system. Company Tekcast Industries has developed a device for centrifugal casting, extending the area of production of castings or prototyping of metal or plastic. Materials suitable for the centrifugal casting with flexible operating parameters may include non-ferrous metal alloy based on zinc or aluminum or non-metallic materials such as polyester resins, polyurethane resins, epoxy resins, waxes and the like. The casting process is particularly suitable for a wide range of commercial castings and decorative objects.
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Abstract

The work determined the influence of aluminium in the amount from about 0.6% to about 8% on graphitization of cast iron with relatively high silicon content (3.4%-3.9%) and low manganese content (about 0.1%). The cast iron was spheroidized with cerium mixture and graphitized with ferrosilicon. It was found that the degree of graphitization increases with an increase in aluminium content in cast iron up to 2.8%, then decreases. Nodular and vermicular graphite precipitates were found after the applied treatment in cast iron containing aluminium in the amount from about 1.9% to about 8%. The Fe3AlCx carbides, increasing brittleness and deteriorating the machinability of cast iron, were not found in cast iron containing up to about 6.8% Al. These carbides were revealed only in cast iron containing about 8% Al.
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Abstract

An initial assessment of the effectiveness of cast iron inoculation, performed by the method of impulse introducing the master alloy into cast iron, is presented. The experiment was concerned with the hypoeutectic gray cast iron inoculated with either the Alinoc or the Barinoc master alloy by means of an experimental device for pneumatic transportation. Examinations involved pneumatic injection of the powdered inoculant carried in a stream of gaseous medium (argon) into the metal bath held in the crucible of an induction furnace. It was found that the examined process is characterised by both high effectiveness and stability.
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