Józef Górny
AbstractThe paper indicates the existence of many references to casting in the ancient literature. Their analysis allows one to enrich the knowledge of the beginnings and the history of the development of casting - one of the oldest technical areas of human activity, which, in ancient times, played a very important role and, as far as one can remember, has been called art. The paper quotes and discusses references indicting that, in ancient times, metals and the skills connected with their treatment and casting were seen as a gift from God or gods, as well as describing the beginnings and significance of casting in old times and the development of casting manufacture technology and pointing to some of the works of the casting art masters of the ancient world.
Keywords: foundry, history, artistic casting, antiquity, ancient literature,
 Download 2.06 MB >>
Andrzej Pytel, Edward Guzik
AbstractThe study presents the general data on modern cast iron with vermicular graphite, developed in Poland, which can be successfully used for casts of machine and device elements, especially those working under the conditions of thermal fatigue.
The mentioned cast iron has better mechanical properties, and its casting properties are close to those of grey cast iron with flake graphite, some of which being more advantageous than those of nodular graphite. And so, it can be alternatively applied for casts in the production of many elements used in various branches of industry. An outline of the authors’ selected own research of this high quality cast iron is presented. The issues discussed in the study, including the properties of cast iron with vermicular graphite as a construction material, as well as examples of its use, should stimulate interest in this material on the side of founders and constructors, and thus, also, its wider application for machine and device components.
Keywords: cast iron with vermicular graphite, structure, mechanical properties, cast iron thermal fatigue,
Download 2.18 MB >>
Zbigniew Konopka, Arkadiusz Chojnacki
AbstractThe article presents research results of the process foundry return influence in the AZ91 alloy charge on the change in the structure of castings made by the high-pressure casting method, with special consideration of the formation of non-metallic inclusions. Based on the observations of inclusions by the scanning microscopy method, the chemical composition of the inclusions in melts with different process scrap contents in the charge was determined.
Keywords: high-pressure die casting, alloy AZ91, non-metallic inclusions, microstructure, process foundry return,
Download 1.6 MB >>
Marta Homa
AbstractThe paper presents a critical analysis of the current state-of-the-art thermo-physical properties of metal composite materials, in which different types of carbon reinforcing phase have been used: graphite, diamond, carbon fibres, carbon nanotubes, fullerene, graphene and graphene oxide.
These materials must possess high thermal conductivity (above 300 W·(m·K)-1), thermal expansion similar to that of the material from which the heat is removed (4-9 × 10-6·K-1), low electric conductivity, high erosion resistance of the electric arc, as well as low and stable contact resistance. The application of various types of carbon reinforcement with a structure of the 2D type, such as carbon nanotubes, fullerenes, graphene or graphene oxide, opens new possibilities in the field of the formation of thermo-physical properties, including thermal conductivity. Unfortunately, advanced metal composites reinforced with a 2D type carbon phase are still rarely used, due to the unsolved technological problems connected with joining the metal matrix with the 2D type carbon phase, which results in unsatisfactory thermal conductivity of these materials as well as a complicated production process and a high price.
Keywords: metal-matrix composites, carbon reinforcement, thermal conductivity,
Download 7.21 MB >>
Krzysztof Saja
AbstractThe procedures of grain refinement and modification of a silicon eutectic in hypo- and transeutectic silumins belong to important factors shaping their microstructure as well as physico-mechanical and technological properties. Due to this fact, the study attempts to address a proper, optimal, selection of refining additions αAl - a solid solution as well as additions modifying the silicon eutectic (αAl + βSi), depending on the eutecticity degree of the Al-Si system. The melts were realized at the Department of Non-Ferrous Metal Alloys of the Foundry Research Institute in Kraków. according to the experiment schedule. The obtained results of the examinations of the mechanical properties (Rm, Rp0.2, A5, Z and HB) underwent statistical treatment. The results, based on elaborate graphic interpretation, enable an easy selection of the amount of refiner (Ti5B1) and modifier of the eutectic silicon (AlSr10), depending on the silicon content (at wt. %) in the Al-Si system.
Keywords: Al-Si alloys, grain refinement, eutectic modification, mechanical properties,
Download 2.39 MB >>
Marcin Małysza, Robert Żuczek, Stanisław Pysz, Andrzej Gil, Piotr Wieliczko, Piotr Kowalski, Krzysztof Wańczyk
AbstractThe development of a new element is a very complex procedure requiring a combination of many factors related to the design and manufacture phases. The most efficient way is to use computer simulation which allows for verification of the whole design and production process. Over the years, the development of computer technologies has allowed for the development of an Integrated Computational Material Engineering (ICME). This method in logical sequence makes it possible to integrate the project activities, to develop new manufacturing methods, to select suitable materials and to verify the final process. Such multi-threaded operations significantly shorten the time required for the production of the prototype which speeds up the implementation of the planned production of the designed casting. The additional advantage of such work is the possibility of ongoing monitoring of the changes and their impact on the final product.
Keywords: ICME, simulation, aluminum alloy, rapid prototyping, casting optimization,
Download 1.35 MB >>
Sylwia Żymankowska-Kumon, Joanna Kolczyk
AbstractLoose rapid hardening masses with synthetic resins, customarily called cold-box technologies, have dominated the process of casting core production. A distinguishing feature of these technologies is the manner of mass preparation without the use of a hardener. The hardening agent (in the gaseous form) is introduced by way of its gasification into the condensed core. In the group of these technologies, the most significant one is the phenol cold-box process (Ashland-cold-box, Pur-cold-box).
The evaluation of the harmfulness of these core sands to the environment requires consideration of the amount and toxicity of the released gases. The main limitation of the cold-box technology with the participation of amine is connected with its neutralization and its harmfulness to the environment. For the evaluation of environmental performance of casting binders, it is suitable to apply pyrolytic testing in combination with the gas chromatography method (Py-GC/MS).
The article presents the results of chromatographic tests of selected products of thermal decomposition (BTEX - mainly benzene, toluene and phenol) of core sand made in the classic cold-box technology. The investigations were performed in inert atmosphere, at the temperature of 500°C and 1200°C.
Keywords: casting, gas chromatography, benzene, phenol, mass spectrometry, pyrolysis,
Download 2.24 MB >>
Łukasz Jamrozowicz, Joanna Kolczyk, Natalia Kaźnica
AbstractThe article presents an analysis of the kinetics of the hardening process of self-hardening masses. In this study, moulding sand with a quartz sand grain matrix by Sibelco, main fraction Fm 0.40; 0.32; 0.20 mm, was used. Two resins were used as binders. The first tests were performed on a mass with phenol-formaldehyde-phurphuril resin (FF/AF), hardened with methylbenzenesulfonic acid. The hardener was added to the mass in two variants: with a low concentration - the so-called "slow" hardener - and a high concentration - the "fast" hardener. The second examined mass was a mass with urea-formaldehyde-phurphuril (MF/AF), which was, in turn, hardened with p-toluenesulfonic acid. Similarly to the case of the first resin, the hardener was applied in two concentrations - low and high. The measurements were made on a bench for ultrasound tests on moulding sands. During the examinations, the course of the hardening process was determined, and more precisely, the change in the time of the longitudinal ultrasound wave’s passing through the newly-prepared moulding sand sample was recorded. On this basis, the velocity of the ultrasound waves passing through the mass in time CL = f(t) was determined, which was, in turn, the basis for the determination of both the change in the hardening degree of the mass in time, that is Sx = f(t), and the kinetics of the hardening process dSx/dt. The tests of the mass binding process were performed at 10°C.
Keywords: loose self-hardening masses, hardening kinetics, ultrasound examinations,
Download 1.44 MB >>
Katarzyna Major-Gabryś, Aleksandra Grabarczyk, Stanisław Marian Dobosz, Dariusz Drożyński
AbstractThe increasing requirements concerning the emission of hazardous substances force the casting industry to search for new, more environment-friendly solutions. Such solutions may include technologies of developing moulding and core sands with the use of organic biodegradable materials as binders. We should, however, remember that the new technologies must ensure high technological properties of the moulding and core sands. This article presents the results of investigations of new binary moulding binders, where part of the phenol-furfuryl resin commonly applied in casting, was replaced by a biodegradable material in the form of polycaprolactone (PCL).
The article discusses the investigations of the effect of the biodegradable material as a component of a new binary binder on the thermal degradation of the binder, its viscosity as well as the selected technological properties of the examined moulding sands, including their thermal deformation and elasticity at ambient temperature. The performed examinations showed that replacing a part of the phenol-furfuryl resin in the binder with the PCL biodegradable material does not affect the thermal degradation of the new binder, while increasing its viscosity. The moulding mixtures with the applied binary binder are characterized by similar technological properties to the moulding sands with the phenol-furfuryl resin only.
Keywords: environment protection, innovative casting materials and technologies, moulding sands, binders, furfuryl resin, biodegradable material,
Download 1.33 MB >>
|
