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EN
In the present work, different Cu-alloyed model ductile irons with ferritic (0%Cu-0.09%Mn), mixed ferritic-pearlitic (0.38%Cu-0.40%Mn) and pearlitic (0.69%Cu-0.63%Mn) microstructure were produced and analyzed in terms of their electrochemical corrosion behavior in a 3.5wt.%NaCl aqueous solution containing naturally dissolved oxygen at room temperature (25°C). The remaining elements such as Si and Mg were kept at balanced levels in an attempt to minimize variations in graphite size and distribution among different samples. The corrosion resistance was evaluated by electrochemical impedance spectroscopy and potentiodynamic polarization. Microstructure analysis of the cast alloys confirmed similarity in the graphite morphology among the different cast samples and the expected variations in the metallic matrix. In the absence of passivation, it was found that the addition of copper led to an increase in corrosion resistance, which could be attested by higher values polarization resistance and corrosion potential.
PL
W niniejszym artykule przedstawiono system wodociągowy, który służy do zaopatrywania w wodę mieszkańców oraz zakładów produkcyjnych w jednostkach osadniczych. Opisano także zalety i wady materiałów dotychczas stosowanych do budowy sieci wodociągowych. Przedstawiono również innowacyjny system rur BLUTOP z żeliwa sferoidalnego dedykowany dla systemów wodociągowych o małym zakresie średnic.
EN
This article presents a water supply system that is used to supply residents in settlement units and production plants in water. The advantages and disadvantages of materials used in the construction of water supply networks have also been described. Also presented is an innovative system of BLUTOP pipes made of ductile iron dedicated for water systems with a small diameter range.
PL
Odlewy z żeliwa sferoidalnego znajdują szerokie zastosowanie w wielu gałęziach przemysłu ze względu na swoje właściwości mechaniczne. Wytwarzanie tego gatunku materiału wymaga utrzymania reżimu technologicznego oraz czystości materiału wyjściowego. Z tego powodu stale rozwijane są metody wytwarzania oraz kontroli tego materiału. W niniejszej publikacji przedstawiona została nowa metoda sferoidyzacji i modyfikacji żeliwa w formie. Innowacją tej metody jest zastosowanie specjalnie opracowanej konstrukcji komory, w której zachodzi reakcja uszlachetniania żeliwa. W artykule przedstawione zostały przeprowadzone badania symulacyjne, mające na celu analizę profilu przepływającego ciekłego metalu w zadanej konstrukcji. Następnie wprowadzone zostały zmiany geometrii komory, celem optymalizacji jej kształtu oraz powtórnie wykonano analizę w tożsamych warunkach brzegowych. Wynikiem badań jest opracowanie konstrukcji, która zapewni odpowiedni charakter przepływu pozwalający na uzyskanie dobrej jakości żeliwa i odlewów z żeliwa sferoidalnego w formie odlewniczej.
EN
Ductile iron castings are widely used in many industrial branches because of their mechanical properties. The production process of such a grade of cast iron requires the maintenance of the technological regime and the purity of initial charge material. For this reason, methods of manufacturing and controlling materials are constantly being developed. This publication presents a new method of modification and spheroidization in the mould. The innovation of this method is the use of specially developed construction of the reaction chamber. Simulation studies were conducted to analyze the flow profile of liquid metal in the developed shapes of the chamber. Subsequently, the changes in the geometry of the chamber were made and analyzed under the same boundary conditions. The result of the study is the designation of a structure that will provide the appropriate flow characteristics to achieve good quality castings.
4
Content available remote Bezwykopowa budowa wodociągów w Bydgoszczy i Gdańsku
PL
Bezwykopowa budowa podziemnej infrastruktury, choć nadal niejednokrotnie wzbudza duże zainteresowanie osób spoza branży, staje się normą, szczególnie, jeśli prace budowlane trzeba przeprowadzić w terenach o gęstej zabudowie, pod ciągami komunikacyjnymi czy przeszkodami naturalnymi. Tak też było w Bydgoszczy i Gdańsku, gdzie do budowy wodociągów zastosowano metodę horyzontalnych przewiertów sterowanych i zainstalowano rury z żeliwa sferoidalnego.
EN
The excellent property combination of thin wall ductile iron castings (TWDI), including thin wall alloyed cast iron (e.g. austenitic TWDI) has opened new horizons for cast iron to replace steel castings and forgings in many engineering applications with considerable cost benefits. TWDI is considered as a potential material for the preparation of light castings with good mechanical and utility properties, the cost of which is relatively low. In this study, unalloyed and high Ni-alloyed (25% Ni) spheroidal graphite cast iron, with an austenitic metallic matrix were investigated. The research was conducted for thin-walled iron castings with 2, 3 and 5mm wall thickness, using different mould temperature (20°C, and 160°C) to achieve various cooling rates. The metallographic examinations i.e. characteristic of graphite nodules, metallic matrix, and primary grains of austenite dendrites (in high-nickel NTWDI) and mechanical properties were investigated. The study shows that homogeneity of the casting structure of thin-walled castings varies when changing the wall thickness and mould temperature. Finally, mechanical properties of thin-walled ductile iron castings with ferritic-pearlitic and austenitic metallic matrix have been shown.
EN
The conducted work shows and confirms how thermal analysis of grey and ductile iron is an important source for calculating metallurgical data to be used as input to increase the precision in simulation of cooling and solidification of cast iron. The aim with the methodology is to achieve a higher quality in the prediction of macro– and micro porosity in castings. As comparison objects standard type of sampling cups for thermal analysis (solidification module M ≈ 0.6 cm) is used. The results from thermal analysis elaborated with the ATAS MetStar system are evaluated parallel with the material quality (including tendency to external and internal defects) of the tested specimen. Significant temperatures and calculated quality parameters are evaluated in the ATAS MetStar system and used as input to calibrate the density curve as temperature function in NovaFlow&Solid simulation system. The modified data are imported to the NovaFlow&Solid simulation system and compared with real results.
7
Content available remote Eksperymentalna weryfikacja wyników symulacji mes toczenia żeliwa sferoidalnego
PL
W niniejszej pracy zaprezentowano metodę eksperymentalnej weryfikacji wyników symulacji numerycznej MES procesu toczenia żeliwa sferoidalnego. We wstępie wyszczególniono czynniki wpływające na efekt końcowy symulacji MES, powodujących konieczność eksperymentalnej weryfikacji badań symulacyjnych. Zaprezentowano metodę weryfikacji otrzymanych wyników symulacji poprzez badania eksperymentalne z użyciem przygotowanego w tym celu stanowiska. Dokonano wzajemnego porównania wyników otrzymanych dla symulacji i eksperymentu oraz sformułowano wnioski końcowe.
EN
The article presents a method of experimental verification of the results of an FEM oblique turning simulation of ductile cast iron. In the introduction, factors affecting the outcomes of FEM simulations are listed, along with their description. A need for experimental validation due to the effect of those factors was stated. The research stand and FEM simulation procedure were explained. Next, experiment and simulation results were presented. The article is concluded with a comparison of obtained results and final conclusions.
PL
Technologia otrzymywania żeliwa sferoidalnego powoduje wydzielenie się grafitu w postaci kulek. Kształt ten w najmniejszym stopniu oddziałuje na obniżenie właściwości mechanicznych żeliwa sferoidalnego. Jego wytrzymałość w głównej mierze zależy od osnowy, zatem od składu chemicznego, kinetyki krzepnięcia i technologii obróbki cieplnej. W niniejszej pracy przedstawiono wyniki badań mikrotwardości i twardości, wyniki badań metalograficznych oraz analizy termicznej dla odlewów cienkościennych z żeliwa sferoidalnego o różnej zawartości niklu. Badania miały na celu określenie wpływu zawartości niklu na strukturę i właściwości żeliwa sferoidalnego w odlewach cienkościennych. W ramach badań założono uzyskanie żeliwa sferoidalnego zawierającego 0,001; 1; 10 oraz 24% Ni. Wykazano, że nikiel stabilizuje austenit. Przy zawartości niklu wynoszącej 24% osiągnięto całkowicie austenityczną osnowę, dla zawartości niklu wynoszącej 10% w osnowie tworzy się martenzyt, wskutek czego znacznie wzrasta twardość żeliwa. Dla niskich zawartości w żeliwie nikiel wykazuje działanie perlitotwórcze.
EN
In the technology of ductile iron manufacture, graphite precipitates take the form of spheroids, and this shape has the least harmful effect on cast iron mechanical properties. The strength of ductile iron depends mainly on its matrix, and hence on the chemical composition, solidification kinetics and heat treatment technology. This article presents the results of micro-hardness and hardness measurements, and the results of metallographic examinations and thermal analysis carried out on thin-walled ductile iron castings with varying nickel content. The main aim of the research was to determine the effect of nickel content on structure and properties of ductile iron in thin-walled castings. To achieve the goal, ductile iron containing 0.001; 1.0; 10 and 24% Ni was manufactured. It has been shown that nickel stabilizes austenite. With the nickel content of 24%, a completely austenitic matrix was obtained, the addition of 10% Ni to the matrix produced martensite, considerably increasing the cast iron hardness. Low content of this additive had a pearlite-forming effect.
PL
CADI (Carbidic ADI) – ausferrytyczne żeliwo sferoidalne z węglikami – jest stosunkowo nowym materiałem inżynierskim wykazującym doskonałą odporność na zużycie ścierne i dostateczną udarność. W niniejszej pracy przebadano wpływ dwustopniowego hartowania izotermicznego na wybrane właściwości żeliwa typu CADI. Dwie partie próbek poddano austenityzacji w 900°C przez 60 min. Następnie pierwszą partię poddano konwencjonalnemu jednostopniowemu hartowaniu izotermicznemu w 4 różnych temperaturach kąpieli solnej: 300, 330, 360 i 390°C przez 120 minut. Drugą partię natomiast poddano dwustopniowemu hartowaniu, początkowo przez 10 min w kąpieli solnej o temperaturze 260°C, a następnie w drugiej kąpieli solnej o temperaturze 300, 330, 360 i 390°C przez 120 min. Uzyskane wyniki pokazują, że w porównaniu z konwencjonalną obróbką cieplną dwustopniowy proces ausferrytyzacji poprawia udarność i odporność na ścieranie żeliwa CADI.
EN
CADI (Carbidic ADI) – ausferritic ductile iron containing carbides – is a relatively new engineering material which exhibits excellent wear resistance and adequate impact strength. In this work the influence of two-step austempering process on selected properties of CADI cast iron was examined. Two batches of samples were initially austenitized at 900°C for 60 min. The first batch of the samples was austempered conventionally by single-step process in a salt bath at 4 different temperatures: 300, 330, 360 and 390°C for 120 min. The second batch was processed by twostep austempering process, first in a salt bath at 260°C for 10 min and subsequently in second salt bath at temperatures 300, 330, 360 and 390°C for 120 min. Results show that two-step austempering process improves impact strength and wear resistance of CADI compared to conventional heat treatment process.
PL
Badania jakości przewodów żeliwnych dostarczanych na duże place budowy są istotne z uwagi na ich trwałość i funkcjonalność. Jednakże interpretacja tych badań nastręcza trudności. Dlatego w artykule omówiono doświadczenia autorów w zakresie trudności w interpretacji zdjęć pęknięć pomiędzy warstewkami rdzy powstałej na ścianach przewodów żeliwnych w czasie ich wyżarzania oraz przedstawiono argumenty przemawiające za tym, że lepiej jest prowadzić badania wytrzymałościowe na prostokątnych próbkach wyciętych podłużnie ze ściany przewodów, niż na próbkach o przekroju kołowym.
EN
The quality tests of ductile iron pipes delivered to large construction sites are important for the pipes durability and functionality. However, the interpretation of those tests is found to be difficult. In a present paper, the authors' experience in the interpreting of crack pictures between the layers of rust, formed on the walls of cast iron pipes during annealing has been discussed. There are indications that it would be better to carry out the strength tests on rectangular samples, cut out lengthwise from the pipe wall, instead on the tensile samples with a circular cross-section.
PL
Pomimo powszechnego dążenia do produkowania coraz lżejszych, tańszych i wytrzymalszych komponentów ze stopów metali lekkich oraz tytanu, to żeliwo jest nadal materiałem dość powszechnie wykorzystywanym w branży mechanicznej, jak również w przemyśle motoryzacyjnym. Produkowane z niego są głownie korpusy elementów układu przeniesienia napędu jak również części wykorzystywane w oprzyrządowaniu silnika. Masowy charakter produkcji w branży motoryzacyjnej wpływa natomiast na konieczność zapewnienia dużej wydajności objętościowej procesu skrawania. W literaturze światowej jest wiele pozycji dotyczących doboru technologicznych para-metrów obróbki przy wysokowydajnym skrawaniu, stali, stopów metali lekkich oraz tytanu. Natomiast w przypadku żeliw takie prace stanowią ułamek procenta publikowanych obecnie prac. Stąd w oparciu o zapotrzebowanie zaspokojenia potrzeb przemysłu oraz chęci poznawczych zespołu badawczego, podjęto się tematyki badań doświadczalnych, których wyniki zostały opisane w poniższym artykule. Celem realizowanych badań było określenie możliwości wykorzystania jednego narzędzia do obróbki zgrubnej i wykończeniowej uwzględniając jedynie możliwości zmiany technologicznych parametrów obróbki dwóch zabiegów zintegrowanych w jednej operacji.
EN
Despite the widespread desire to produce lighter, cheaper and more durable components from light metal alloys and titanium, cast iron is still a material widely used in the mechanical industry as well as in the automotive industry. The parts used in the engine's instrumentation are mainly produced from it. However, the mass nature of production in the automotive industry affects the need to ensure high volume efficiency of the cutting process. In the world science literature there are many items regarding the selection of technological machining parameters for high-performance machining, steel, light metal alloys and titanium. In the case of cast irons, such works constitute a fraction of a percentage of the currently published works. Therefore, on the basis of the demand to meet the industry's needs and the cognitive intentions of the research team, the subject of experimental research was carried out and the results of which were described in the following article. The aim of the research was to determine the possibility of using one tool for roughing and finishing machining, taking into account only the possibility of changing the technological parameters of processing two treatments integrated in one operation.
EN
An intentional change in material properties is an important condition for castings production. It is one way how to meet the casting requirements of how to adapt the material properties to the operating conditions. Centrifugally cast rolls are multi-layer rollers, castings. The working layer of the barrel is called the "shell" and the body of the roll and the necks rolls are called "core". The article deals with the influence of the properties of the core iron. Earlier laboratory experiments were primary analysed for metallographic analysis and mechanical properties. These data were compared back to the experiments. The results of these laboratory working were later applied in the operating conditions of the roll foundry Vítkovitcké slévárny, spol. s r.o. The spun cast roll produced with the applied metallurgical processing change was supplied to the hot strip mill. There were monitored the positive effect of the change of the metallurgical process of the production of the core iron on the useful properties of the centrifugally cast roll. The experiment was done in order to increase the mechanical properties of ductile pearlite ductile iron. The copper in these core iron material increases the hardness and strength primarily.
EN
In the family of iron-based alloys, ductile iron enjoys the highest rate of development, finding application in various industries. Ductile iron or the cast iron with spheroidal graphite can be manufactured by various methods. One of them is the Inmold spheroidization process characterized by different technological solutions, developed mainly to increase the process efficiency. So far, however, none of the solutions has been based on the use of a reactor made outside the casting mould cavity. The method of spheroidization inside the casting mould using a reaction chamber developed at the Foundry Research Institute is an innovative way of cast iron treatment. The innovative character of this method consists in the use of properly designed and manufactured reactor placed in the casting mould cavity. Owing to this solution, the Inmold process can be carried out in moulds with both horizontal and vertical parting plane. The study presents the results of examinations of the microstructure of graphite precipitates and metal matrix of castings after spheroidization carried out by the Inmold process using a reactor and mould with vertical parting plane. Special pattern assembly was made for the tests to reproduce plates with wall thicknesses of 3; 5; 7; 10; 20 and 30 mm. The content of residual magnesium was determined for all tested castings, while for castings of plates with a wall thickness equal to or larger than 10 mm, testing of mechanical properties was additionally performed.
EN
The effectiveness of cast iron spheroidization with FeSiMg master alloy by the traditional method and using a reaction chamber placed in the cavity of foundry mould was compared. The method of cast iron treatment in mould cavity using a reaction chamber is an innovative technology developed by the Foundry Research Institute in Krakow. The effectiveness of the spheroidization process carried out by both methods was checked on a series of test castings. The article also presents the results of metallographic examinations and mechanical testing, including the discussion of magnesium yield and its assimilation rate.
EN
Two different spheroidization methods were compared in terms of the effect they may have on gas content (oxygen, nitrogen and hydrogen) in ductile iron castings and process efficiency. Two methods of cast iron treatment were investigated, i.e. spheroidization in the foundry mould using a reaction chamber (reactor) developed by the Foundry Research Institute and, as a reference, the method currently used by foundry shops, i.e. spheroidization in the foundry ladle. The effect of spheroidization process was evaluated on test castings. The results of metallographic examinations and mechanical tests as well as the results of measurements of the oxygen, nitrogen and hydrogen content in cast iron after spheroidizing treatment were presented.
EN
High complexity of the physical and chemical processes occurring in liquid metal is the reason why it is so difficult, impossible even sometimes, to make analytical models of these phenomena. In this situation, the use of heuristic models based on the experimental data and experience of technicians is fully justified since, in an approximate manner at least, they allow predicting the mechanical properties of the metal manufactured under given process conditions. The study presents a methodology applicable in the design of a heuristic model based on the formalism of the logic of plausible reasoning (LPR). The problem under consideration consists in finding a technological variant of the process that will give the desired product parameters while minimizing the cost of production. The conducted tests have shown the effectiveness of the proposed approach.
EN
The completed research presented in the first part of the article has allowed linking the manufacturing technology of ductile iron castings with the process of hot dip galvanizing. On the basis of these data simulations were carried out to examine the behaviour of zinc diffusion coefficient D in the galvanized coating. The adopted model of zinc coating growth helped to explain the cases of excessive growth of the intermetallic phases in this type of coating. The paper analyzes covered the relationship between the roughness and phase composition of the top layer of product and the thickness and kinetics of zinc coating growth referred to individual sub-layers of the intermetallic phases.Roughness and phase composition in the surface layer of product were next related to the diffusion coefficient D examined in respective sublayers of the intermetallic phases.
EN
Studies have demonstrated that in the process of hot dip galvanizing the decisive influence on the mechanism of zinc coating formation and properties has the quality of the mechanically untreated (raw) surface layer of the galvanized product. The terms “casting surface layer” denote various parameters of the microstructure, including the type of metal matrix, the number of grains and the size of graphite nodules, possible presence of hard spots (the precipitates of eutectic cementite) and parameters of the surface condition. The completed research has allowed linking the manufacturing technology of ductile iron castings with the process of hot dip galvanizing.
19
Content available Multiphase Ausformed Austempered Ductile Iron
EN
Ductile iron was subjected to a total true strain (φt) of 0.3 either by applying φt in the austenite region or by apportioning it through applying a true strain of 0.2 in the austenite region before quenching to austempering temperature (TA) of 375°C, where a true strain of 0.1 is applied (ausforming). Additionally, two types of matrices were produced in the ductile iron, namely ausferritic and ferritic-ausferritic matrices. The ferrite is introduced to the matrix by intercritical annealing after austenitization. Dilatometric measurements as well as microstructure examination showed a fast ausferrite transformation directly after applying φA and that the introduction of ferrite to the matrix resulted in a remarkable acceleration of the ausferrite formation. The transformation kinetics, microstructure evolution, hardness and compression properties are studied.
EN
The results of examinations of microstructure and an analysis of its impact on selected mechanical properties of austempered ductile iron (ADI) were presented in the paper. The ADI was produced from the ductile iron containing 1.56% Ni only alloying addition. The effect of the austempering time and temperature on the microstructure and mechanical properties of the examined cast iron was considered. Constant conditions of austenitizing were assumed and six variants of the austempering treatment were adopted. The studyof mechanical properties included a static tensile test, Charpy impact strength test and Brinellhardness measurement. This work complements the knowledge about alloying additions effect on microstructure and mechanical properties of ADI and focuses on the impact of a single alloying element (Ni).
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