Ograniczanie wyników
Czasopisma help
Autorzy help
Lata help
Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 39

Liczba wyników na stronie
first rewind previous Strona / 2 next fast forward last
Wyniki wyszukiwania
Wyszukiwano:
w słowach kluczowych:  forma ceramiczna
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 2 next fast forward last
EN
This paper presents practical capabilities of a system for ceramic mould quality forecasting implemented in an industrial plant (foundry). The main assumption of the developed solution is the possibility of eliminating a faulty mould from a production line just before the casting operation. It allows relative savings to be achieved, and faulty moulds, and thus faulty castings occurrence in the production cycle to be minimized. The numerical computing module (the DEFFEM 3D package), based on the smoothed particle hydrodynamics (SPH) is one of key solutions of the system implemented. Due to very long computing times, the developed numerical module cannot be effectively used to carry out multi-variant simulations of mould filling and solidification of castings. To utilize the benefits from application of the CUDA architecture to improve the computing effectiveness, the most time consuming procedure of looking for neighbours was parallelized (cell-linked list method). The study is complemented by examples of results of performance tests and their analysis.
2
Content available Influence of Zr on AlSi9Cu1Mg Alloy Cast in Ceramic
EN
The article focuses on the analysis of the effect of Zr on the properties of the aluminium alloy AlSi9Cu1Mg. The effect of Zr was evaluated depending on the change in mechanical properties and heat resistance during a gradual addition of Zr with an increase of 0.05 wt. % Zr. Half of the cast experimental samples from each variant were heat treated by precipitation hardening T6 (hereinafter HT). The measured values in both states indicate an improvement of the mechanical properties, especially in the experimental variants with a content of Zr ≥ 0.20 wt. %. In the evaluation of Rm, the most significant improvement occurred in the experimental variant with an addition of Zr 0.25 wt. % after HT and E in the experimental variant with addition of Zr 0.20 wt. % after HT. Thus, a difference was found from the results of the authors defining the positive effect of Zr, in particular at 0.15 wt. %. When evaluating the microstructure of the AlSi9Cu1Mg alloy after Zr alloying, Zr phases are already eliminated with the addition of Zr 0.10 wt. %. Especially at higher levels of Zr ≥ 0.20 wt. %, long needle phases with slightly cleaved morphology are visible in the metal matrix. It can be stated that a negative manifestation of Zr alloying is expressed by an increase in gassing of experimental alloys, especially in variants with a content of Zr ≥ 0.15 wt. %. Experimental samples were cast into ceramic moulds. The development of an experimental alloy AlSi9Cu1Mg alloyed with Zr would allow the production of a more sophisticated material applicable to thin-walled Al castings capable of operating at higher temperature loads.
EN
The article presents the role of the ceramic layered moulds used in the investment casting method with new (certified) and recycled material from ceramic moulds (CM) after casting process. The materials that were obtained are mainly aluminosilicates and SiO2. The investigation of changes in the quality of ceramic moulds (including the recycled ceramic material) includes the chemical composition of the ceramics as recovered ceramic material, changes in the particle size of the layered covering material, the gas permeability during the pouring of liquid metal, and the creation of the porosity are presented. Than the thermophysical parameters and dimensional accuracy of the casting manufactured in the new ceramic layered shell moulds were analysed. Additionally the global cost savings and improved ecological conditions in the foundry and its surroundings was estimated.
EN
This work focuses on the influence of temperature distribution in a shell mould during investment casting of thin wall parts on macrostructure, chemical composition of microstructural constituents and γ/γ′ misfit parameter. A reduction of production costs is associated with the optimization of precision casting technology of aircraft engine critical parts, including control of the solidification front in thin-walled castings of nickel superalloys. Appropriate lost-wax casting parameters lead to the creation of coarse grained structure, desired for high-temperature service applications. As a result of non-equilibrium solidification, substantially large chemical inhomogeneities in the dendrite core and interdendritic spaces are formed. Interdendritic spaces are occupied by constituents formed as a consequence of segregation of alloying elements, namely eutectic islands γ/γ′, borides, carbides, and an intermetallic compound of Ni and Zr. Dendrite cores consist of cubic-shaped γ′ precipitates surrounded by Ni-rich γ channels. Low lattice misfit influences cubic morphology of γ′ precipitates, which is favourable for jet engine application because it can guarantee good creep resistance.
EN
The investigation results of the kinetics of binding ceramic moulds, in dependence on the solid phase content in the liquid ceramic slurries being 67, 68 and 69% - respectively, made on the basis of the aqueous binding agents Ludox AM and SK. The ultrasonic method was used for assessing the kinetics of strengthening of the multilayer ceramic mould. Due to this method, it is possible to determine the ceramic mould strength at individual stages of its production. Currently self-supporting moulds, which must have the relevant strength during pouring with liquid metal, are mainly produced. A few various factors influence this mould strength. One of them is the ceramic slurry viscosity, which influences a thickness of individual layers deposited on the wax model in the investment casting technology. Depositing of layers causes increasing the total mould thickness. Therefore, it is important to determine the drying time of each deposited layer in order to prevent the mould cracking due to insufficient drying of layers and thus the weakening of the multilayer mould structure.
EN
The results of microstructure investigations of IN 713C superalloys obtained as thin walled‚ wedge’ castings from three kinds of shell molds are presented. Light microscopy, scanning electron microscopy observations and secondary dendrite arm spacing (SDAS) measurements were used to determine the differences in the IN 713C castings obtained using three kinds of shell mold materials. The effects of major constituents of the three shell molds: zirconium silicate ZrSiO4, aluminosilicate mAl2O3 . nSiO2 and SiC-based system on the SDAS in the investigated castings of the IN 713C superalloy are described. The results confirm that crystallization conditions (the variable wall thickness of the casting and material of the shell) of the IN 713C castings influence their microstructure. The increased SiC content in the shell molds has an effect on the crystallization process kinetics as indicated by the changes in the observed secondary dendrite arm spacing.
PL
Powszechnie wiadomo, że parametry procesu odlewania mogą wpływać na mikrostrukturę i właściwości mechaniczne nadstopów na osnowie niklu. Zmniejszenie odległości między ramionami wtórnymi dendrytów (SDAS) prowadzi do zredukowania porowatości i obszarów eutektyki w odlewie. Celem przeprowadzonych badań było ustalenie wpływu grubości ścianki odlewu oraz składu materiału i właściwości cieplnych formy ceramicznej na odległości między ramionami wtórnymi dendrytów w odlewach z nadstopu IN 713C.
EN
Results of analysis presented in this paper were based on analysis of casts made especially for this research purpose and related to actual cast – industrial. The evaluation of the dimensional accuracy of casts was made in relation to the pressure of the liquid metal with consideration of the ceramic mould temperature. Ceramic moulds used in these analyses were made from crystalline quartz with an aqueous colloidal silica binder containing polymers (KK), and ethyl silicate (KE).
PL
Przeprowadzono badania właściwości technologicznych opracowanych w Instytucie Odlewnictwa doświadczalnych mieszanek gipsowych. Opracowano mieszanki masy ceramicznej, w których podstawowym materiałem jest gips syntetyczny. Składniki opracowanej mieszanki badano w celu określenia podstawowych właściwości technicznych i użytkowych. Wyniki badań przedstawiono na rysunkach.
EN
Research was carried out on the technological properties of plaster mixtures developed at the Foundry Research Institute. Developed were mixtures of ceramic compounds in which the basic material was synthetic plaster. The components of the developed compound were examined in order to determine basic technical and commercial properties. The test results are presented in the figures.
EN
The authors have made an attempt to enrich the knowledge about the influence of wax pattern washing process and its influence on the quality of the shell prime coat. Two types of wax were investigated: A7Fr/60 and KC2690. A7Fr60 is used for pattern fabrication, while KC2690 is typical sprue wax. The goal of work was to establish wax solubility accuracy in Trisol 60 Plus and Houghto Clean 530 versus time and influence of dipping time to wax samples surface quality. Additionally, after exposition of wax samples, their surface morphology was characterized with the use of laser profilometry and surface roughness measurement. The quality of formed prime coat was established by X-ray tomography. The measurement of wetting angle of the wax by binder was conducted. The results have shown that the main factor which influences the quality of the prime coat is surface wettability rather than wax surface roughness.
EN
In the opinion of metrologists, technologists and trybologists surface microgeometry is one of the most important factors affecting the performance characteristics of the machine parts (resistance to wear, sliding and lubricating properties, durability and tightness of joints, fatigue strength, corrosion resistance, etc.). The analysis was made of the ceramic mould elements structure influence on the microgeometry of steel castings surface and their dimensional accuracy. To assess the structure of the ceramic mould previous studies made with usage of computer tomography where used, those studies highlight the ceramic mould structure anisotropy and its properties.
EN
This paper provides an analysis of experimental research and results of investment casting process. Temperature field in a ceramic mold is one of the problems during numerical simulation. Reducing the costs of production in precision casting involves the reduction of scraps, which is one of the fundamental problems of the foundry industry. Reducing these costs is associated with optimization of precision casting technology of aircraft engines critical parts, including control of the solidification front in thin-walled castings of nickel super alloys cast in a vacuum. It is achieved by changing the geometrical characteristics of the ceramic mold. The results of the tests were used to optimize the industrial production of aircraft components in Precision Foundry of WSK Rzeszów. Temperature distribution gained in the conducted tests allowed verification and optimization of computer simulations.
EN
Shape accuracy analysis of aluminum alloy castings was made in function of ceramic mould properties. Taken it to account was anisotropy of those properties, including influence of ceramic mould properties on the porosity of castings. Ceramic moulds strains, which occur in sintering phase, were evaluated with taking into account the design and production process.
EN
The new investigation method of a permeability of ceramic moulds applied in the investment casting technology, is presented in the paper. Some concepts of performing permeability measurements are shown. Investigations in which the influence of the solid phase fraction in the liquid ceramic moulding sand (LCMS) on a permeability of a multi-layer ceramic mould were performed and discussed. The permeability was estimated during two the most important stages of the technological process: in the first – after wax melting and in the second – after mould annealing. Also an influence of the matrix grain sizes (material for sprinkling) on a ceramic mould permeability was estimated.
PL
W pracy przedstawiono nową metodę badań przepuszczalności form ceramicznych stosowanych w technologii wytapianych modeli. Zaprezentowano koncepcje prowadzenia pomiarów przepuszczalności form ceramicznych. Wykonano badania, w których określono wpływ udziału fazy stałej w ciekłej masie ceramicznej (CMC) na przepuszczalność wielowarstwowej formy ceramicznej. Oceniono przepuszczalność w dwóch najważniejszych etapach procesu technologicznego: w pierwszym - po wytopienia wosku oraz w drugim - po wyżarzeniu formy. Oceniono również wpływ wielkości ziarna osnowy, zwanej potocznie „obsypką” (materiałem do obsypywania), na przepuszczalność formy ceramicznej.
PL
Niniejsza praca dotyczy badań na temat możliwości wytworzenia materiałów spiekanych w procesie recyklingu form ceramicznych użytych do wykonania precyzyjnych odlewów elementów silników lotniczych. Na podstawie przeprowadzonych badań proszków przed i po procesie mielenia oraz prób ich prasowania i spiekania stwierdzono, że możliwy jest proces recyklingu zużytych form ceramicznych, stosowanych na odlewy precyzyjne elementów silników lotniczych. Do prasowania stosowano proszki ze zmielonych form bez dodatków oraz z dodatkami modyfikatorów. W obu przypadkach uzyskano dobre rezultaty w procesie prasowania i spiekania. Powierzchnie wyprasek i spieczonych próbek były gładkie i nie ulegały rozwarstwieniu, a także nie wykruszały się.
EN
The present work relates to investigations of the possibility to produce sintered materials in the recycling process of ceramic moulds coming from precise casts for air engines elements. On the basis of conducted investigations of powders before and after milling, and tests of their pressing and sintering it has been affirmed that the recycling process of the spent ceramic moulds is possible. It was applied to presses the powders derived from the ground moulds with and with no additions of modifiers were studied. Both types of the powders gave good results when processed by pressing and sintering. Surfaces of compacts and sintered bodies were smooth, and did not undergo foliation, and also they did not crumble.
PL
Przedstawiono analizę możliwości wykorzystania w odlewnictwie gipsu odpadowego (syntetycznego) uzyskiwanego w procesie odsiarczania spalin w energetyce. Energetyka jest jednym z największych producentem SO2. W celu ochrony środowiska i obniżenia ilości zanieczyszczeń stosuje się odsiarczanie spalin metodą mokrą. W wyniku tego procesu powstaje gips odpadowy, który może być stosowany w praktyce. Przeprowadzono badania, w wyniku których określono sposoby przygotowania tego gipsu do wykonywania form odlewniczych. W artykule oceniono skład chemiczny, wytrzymałość i przepuszczalność form z uzyskanego gipsu syntetycznego, porównano je z właściwościami gipsu odlewniczego GoldStar XL oraz właściwościami form ceramicznych. Zbadano strukturę gipsów, wykonano badania na derywatografie oraz określono energochłonność procesu wytwarzania gipsu odpadowego w instalacji mokrego odsiarczania. Po analizie zebranych danych można stwierdzić, że gips syntetyczny może być używany jako materiał na formy odlewnicze. Nie obserwuje się znaczącego spadku najważniejszych właściwości, a z drugiej strony istnieje wiele dodatkowych korzyści, w tym niskie zużycie energii, obniżenie kosztów i zmniejszenie wpływu na środowisko.
EN
This article investigates possible use of waste gypsum (synthetic), recovered via flue-gas desulfurization from coal-fired electric power plants, in foundries. Energy sector, which in Eastern Europe is mostly composed from coal-fired electric power plants, is one of the largest producers of sulfur dioxide (SO2). In order to protect the environment and reduce the amount of pollution flue-gas desulfurization (FGD) is used to remove SO2 from exhaust flue gases of fossil-fuel power plants. As a result of this process gypsum waste is produced that can be used in practical applications. Strength and permeability tests have been made and also in-depth analysis of energy consumption of production process to investigate ways of preparing the synthetic gypsum for casting moulds application. This paper also assesses the chemical composition, strength and permeability of moulds made with synthetic gypsum, in comparison with moulds made with traditional GoldStar XL gypsum and with ceramic molds. Moreover examination of structure of synthetic gypsum, the investigations on derivatograph and calculations of energy consumption during production process of synthetic gypsum in wet flue-gas desulfurization were made.
EN
In contrast to casting to conventional non-reusable 'sand' moulds, for which calculating technique for an optimum design of the gating system is comparatively well-developed, a trial-and-error method is applied mostly for casting to ceramic shell moulds made by the investment casting technology. A technologist selects from gating systems of several types (that are standardized by the foundry mostly) on the basis of experience. However, this approach is not sustainable with ever growing demands on quality of castings and also the economy of their fabrication as well as with new types of complex sizeable castings introduced to the production gradually (by new customers from the aircraft industry above all) any more. The simulation software may be used as a possible tool for making the process of optimising gating systems more effective.
EN
This article investigates possible use of waste gypsum (synthetic), recovered via flue-gas desulfurization from coal-fired electric power plants, in foundries. Energy sector, which in Eastern Europe is mostly composed from coal-fired electric power plants, is one of the largest producers of sulfur dioxide (SO2). In order to protect the environment and reduce the amount of pollution flue-gas desulfurization (FGD) is used to remove SO2 from exhaust flue gases of fossil-fuel power plants. As a result of this process gypsum waste is produced that can be used in practical applications. Strength and permeability tests have been made and also in-depth analysis of energy consumption of production process to investigate ways of preparing the synthetic gypsum for casting moulds application. This paper also assesses the chemical composition, strength and permeability of moulds made with synthetic gypsum, in comparison with moulds made with traditional GoldStar XL gypsum and with ceramic moulds. Moreover examination of structure of synthetic gypsum, the investigations on derivatograph and calculations of energy consumption during production process of synthetic gypsum in wet flue-gas desulfurization were made. After analysis of gathered data it's possible to conclude that synthetic gypsum can be used as a material for casting mould. There is no significant decrease in key properties, and on the other hand there is many additional benefits including low energy consumption, decreased cost, and decreased environmental impact.
PL
W referacie przedstawiono analizę parametrów powodujących anizotropię właściwości fizycznych form ceramicznych wpływającą na jakość odlewów z aluminium. Przeprowadzono ocenę oryginalnych badań takich, jak przepływ gazów przez ścianki formy, trzypunktowa ocena wytrzymałości formy na zginanie, stan warstwy wierzchniej formy w aspekcie jej zwilżalności przez ciekły metal oraz sprawdzono porowatość formy ceramicznej w badaniach z użyciem tomografu komputerowego. Przeprowadzono ocenę wpływu właściwości form ceramicznych na jakość odlewów w aspekcie ich wytwarzania.
EN
The paper presents analysis of parameters affecting the anisotropy of ceramic moulds physical properties which affect quality of aluminum castings. An evaluation of original research, such as the permeability of mould surface, three-point bending strength, the state of mould surface layer in terms of wettability by the liquid metal, and ceramic molud porosity tested in studies using a CT (computerized tomography) scanner. Investigation of impact made by ceramic mold properties on casting quality in terms of their production was also made.
EN
Ceramic moulds applied in the investment casting technology are multilayer structures, built in an alternating process of depositing and drying of successive layers. Each individual layer is formed from a fluid (liquid) ceramic moulding sand and a grain matrix. In the current, environmentally technology fluid ceramic sands based on ethyl silicate are being substituted by ceramic sands containing colloidal silica as a binder. The ability and rates of drying and hardening of these new colloidal (water) ceramic moulding sands are quite different than of the ones which have a binder dissolved in alcohol. The kinetics of the process based on new binders is not well known. The technological principle requires that the successive layer deposition is done only when the one deposited previously is already sufficiently dry. Investigations of the possibility of application of some methods including: ultrasound, resistance and weigh method are presented in the paper. Advantages and disadvantages of each method are indicated as well as the assessment of their practical suitability is perfomed.
PL
Formy ceramiczne stosowane w technologii wytapianych modeli są konstrukcjami wielowarstwowymi, tworzonymi w przemiennym procesie nanoszenia i suszenia kolejnych warstw. Każda pojedyncza warstwa formy tworzona jest z ciekłej masy ceramicznej i osnowy ziarnowej. W aktualnej, proekologicznej technologii zastępuje się ciekłe masy ceramiczne oparte na krzemianie etylu masami ceramicznymi zawierającymi krzemionkę koloidalną jako spoiwo. Zdolność i szybkość wysychania i utwardzania nowych, koloidalnych (wodnych) mas ceramicznych jest zdecydowanie inna od mas ze spoiwem rozpuszczanym w alkoholu. Kinetyka procesu opartego na nowych spoiwach jest stosunkowo słabo poznana. Zasadą technologiczną jest, aby kolejną warstwę nanosić dopiero wtedy, gdy wcześniej naniesiona wyschła w dostatecznym stopniu. W pracy prezentowane są badania nad możliwością zastosowania kilku metod w tym: metody ultradźwiękowej, opornościowej i wagowej. Wykazano zalety i wady każdej z nich jak również dokonano oceny ich praktycznej przydatności.
EN
Production technology of nwestment casting involves transmitting the elements of shape, dimensions and properties by filling in the appropriate liquid metal ceramic forms reproduced by a model made of wax removed by melting it. The manufacturing process of inwestment casting in the lost wax technology consists of a number of technological operations: preparing of wax models and their assembling in the model units, the preparation of ceramic mixture, successive layers of debris, wax melting in an autoclave, drying the samples at 100 °C, heating the samples at temperatures ranging from 400 to 700 °C. So far, the technology was based on the use of ceramic mixture, which the bond was hydrolysed ethyl silicate. Currently, due to environmental protection and improvement of working conditions, more and more binders with alcohol is replaced with an aqueous solution of colloidal silica. In the study, to create the individual layers a ceramic form, used regenerated ceramic mixture derived from foundry and green ingredients. The regeneration time was respectively 5 and 15 minutes. Used ceramic moulds after mechanical reclamation was given to sieve analysis to determine the grain size (di). Grain sizes 0.2, 0.4 and 0.63 mm were used for the coating of ceramic moulds. The paper presents results of research aimed at the determination of the relationship between tensile wet strength and grain size of ceramic mould: Rm = f[dL). Tests were conducted on cylindrical samples, which deposited the layers of reclaimed ceramic material.
PL
Technologia wytwarzania precyzyjnych odlewów polega na nadawaniu elementom kształtu, wymiarów i odpowiednich własności poprzez wypełnienie ciekłym metalem formy ceramicznej odtworzonej przez model wykonany z wosku, usuwany z niej metodą wytapiania. Proces wytwarzania odlewów precyzyjnych w technologii wytapianych modeli składa się z szeregu operacji technologicznych obejmujących: wykonanie modeli woskowych i ich łączenie w zespoły modelowe, przygotowanie masy ceramicznej, nanoszenie kolejnych warstw, wytopienie wosku w autoklawie, suszenie próbek w temperaturze 100 °C, wygrzewanie próbek w zakresie temperatury od 400 do 700 °C. Dotychczasowa technologia oparta była na stosowaniu mas ceramicznych, w których spoiwem był zhydrolizowany krzemian etylu. Aktualnie, ze względu na ochronę środowiska i poprawę warunków pracy, coraz częściej spoiwo z alkoholem zastępowane jest wodnym roztworem krzemionki koloidalnej. W badaniach do tworzenia warstw formy ceramicznej stosowano osnowy pochodzące ze zużytych form z odlewni precyzyjnej poddanych regeneracji oraz osnowę świeżą. Czas regeneracji wynosił odpowiednio 5 i 15 minut. Masę po regeneracji mechanicznej poddano analizie sitowej w celu określenia wielkości ziarna dL. Ziarna o wielkości 0,2; 0,4 i 0,63 mm użyto do wykonywania warstw form ceramicznych. W artykule przedstawiono wyniki badań ukierunkowanych na wyznaczeniu zależności pomiędzy wytrzymałością na rozciąganie w stanie na wilgotno i wielkością ziarna osnowy formy ceramicznej: Rm =f(dL). Badania zostały przeprowadzone na próbkach w kształcie walca o powierzchni dzielonej, na które nanoszono warstwy z wykorzystaniem osnowy pochodzącej z regeneracji, jak również ze świeżej osnowy.
first rewind previous Strona / 2 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.