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EN
The object of the present paper is to determine the distribution of admixing elements, such as magnesium, manganese, silicon and sulfur, in the boundary layer of the main inlet of a ductile iron casting. The authors also intend to demonstrate the influence of elements diffusing from the casting mold, such as oxygen and silica, on the chemical composition of the boundary layer of the casting.
EN
The study presents a mathematical model of the crystallisation of nodular graphite cast iron. The proposed model is based on micro- and macromodels, in which heat flow is analysed at the macro level, while micro level is used for modelling of the diffusion of elements. The use of elementary diffusion field in the shape of an averaged Voronoi polyhedron [AVP] was proposed. To determine the geometry of the averaged Voronoi polyhedron, Kolmogorov statistical theory of crystallisation was applied. The principles of a differential mathematical formulation of this problem were discussed. Application of AVP geometry allows taking into account the reduced volume fraction of the peripheral areas of equiaxial grains by random contacts between adjacent grains. As a result of the simulation, the cooling curves were plotted, and the movement of "graphite-austenite" and "austenite-liquid” phase boundaries was examined. Data on the microsegregation of carbon in the cross-section of an austenite layer in eutectic grains were obtained. Calculations were performed for different particle densities and different wall thicknesses. The calculation results were compared with experimental data.
EN
The work compares the effectiveness of selected methods of graphitizing inoculation applied after the spheroidization in the slender tundish ladle of 1 Mg capacity. The inoculation was carried out according to the three various options. The first one was performed simply by means of the block of inoculant inserted in the gating system of the mould, the second one started with initial inoculation by the in-stream method during the transfer of metal from the slender ladle to the pouring ladle and was completed with the secondary modification by means of the inoculant insert placed in the mould, the third one consisted in similar initial inoculation by the in-stream method during the transfer of metal from the slender ladle to the pouring ladle followed by the secondary inoculation, again by the in-stream method, applied during the pouring operation. Examination of cast iron structure allowed to find that the best results of inoculation are achieved in the case of inoculation carried out according to the Option III, though in all cases it was possible to produce cast iron of EN-GJS-400-15 grade meeting the demands of the Standard.
4
Content available remote Wpływ parametrów obróbki cieplnej na kształtowanie mikrostruktury żeliwa ADI
PL
W pracy przedstawiono wyniki badań mikrostruktury żeliwa sferoidalnego w stanie odlanym oraz po dwustopniowej obróbce cieplnej (austenityzacja w 900°C i wygrzewanie izotermiczne w 280, 330 i 380°C). Za pomocą programu komputerowego LUCIA oceniono cechy morfologii grafitu oraz osnowy metalowej. Metodą spektroskopii Mössbauera dokonano oceny składu osnowy żeliwa ADI, co umożliwiło określenie udziału austenitu wykazującego właściwości paramagnetyczne. Wyniki tych pomiarów, w połączeniu z wynikami badań kalorymetrycznych pozwoliły na dokonanie opisu procesów przebiegających podczas wygrzewania izotermicznego. Na wykresach kalorymetrycznych podczas nagrzewania żeliwa ADI stwierdzono obecność silnego efektu egzotermicznego, którego początek przemieszcza się od 468°C do 489°C w miarę podwyższania temperatury wygrzewania izotermicznego. Wartość entalpii tego efektu zmienia się proporcjonalnie do zmiany udziału austenitu w żeliwie skutkiem obróbki cieplnej. Na tej podstawie stwierdzono, że proces powstawania osnowy żeliwa, składającej się z ferrytu i stabilnego, przesyconego węglem austenitu, ma charakter endotermiczny i wymaga dostarczenia energii do układu.
EN
This paper gives the results of microstructure investigations of ductile cast iron in as-cast condition and after two-stage heat treatment (austenitisation at 900°C and isothermal soaking at 280, 330 and 380oC). The morphological features of graphite and metallic matrix were determined using LUCIA software. The Mössbauer spectroscopy method was used to determine the composition of ADI cast iron matrix, which enabled the determination of the share of austenite which demonstrated paramagnetic properties. In combination with the results of calorimetric investigations, the results of these measurements enabled the processes occurring during isothermal soaking to be described. While heating ADI cast iron, the presence of strong exothermal effect, the beginning of which transferred from 468°C to 489°C as the isothermal soaking temperature was increasing, was found on calorimetric diagrams. The enthalpy value of this effect changes in proportion to the change in the share of austenite in cast iron as a result of heat treatment. Based on that, it was found that formation of cast iron matrix consisting of ferrite and stable carbon supersaturated austenite is of endothermic nature and requires the supply of energy to the system.
EN
The paper presents the influence of the treatment with cerium mixture and postinoculation with ferrosilicon on the structure of cast iron containing about 5% of aluminium. Rod samples of three different diameters (10 mm, 20 mm, 30 mm) have been examined. The desired test samples have been cast directly after modification, then 5 minutes after, and then 10 minutes after that treatment, to assess the relationship between treatment efficiency and time. It has been found that the introducing about 0.14% of cerium mix into the aluminium cast iron has resulted in occurring the nodular graphite precipitates accompanied by chunky-type graphite in the alloy.
6
EN
The work presents the effect of cerium mischmetal used in quantities of 0.1 and 0.2 wt-% and ferrosilicon used in quantities from 0.5% to 1.5% on the alloy matrix and the shape of graphite precipitates in the low-aluminium cast iron from seven heats, basing on the examination of its structure. The hypereutectic cast iron of the relatively high carbon content (4.0÷4.2%) at the prior-to-treatment silicon and manganese content equal to ca. 0.6% and ca. 0.04%, respectively, has been examined. It has been found that the performed treatment leads to the change in the alloy matrix from the nearly almost pearlitic to the ferritic-pearlitic one accompanied by changes in the shape of graphite precipitates. Due to applying both of the mentioned substances in the above stated amounts the graphite precipitates in cast iron have taken the shape of nodular and vermicular ones, and no presence of flake graphite has been revealed. A quantitative analysis of the performed treatment i.e. determining the fractions of graphite precipitates of different shapes has been possible by means of a computer image analyser.
EN
The results of studies on the use of FeSi5%Mg magnesium alloy in modern cored wire injection method for production of nodular and vermicular graphite cast irons were described. The injection of Mg cored wire length is a treatment method which can be used to process The injection of Mg cored wire length is a treatment method which can be used to process iron melted in an electric induction furnace. This paper describes the results of using a high-magnesium ferrosilicon alloy in cored wire (Mg recovery 47-70%) for the production of vermicular and nodular graphite cast irons at in at least 13 foundries. The results of calculations and experiments have indicated the length of the cored wire to be injected basing on the initial sulfur content and weight of the treated melt. The results of numerous trials have shown that the magnesium cored wire process can produce high quality nodular and vermicular graphite irons under the specific industrial conditions of the above mentioned foundries. It has also been proved that in the manufacture of nodular graphite iron, the cost of the nodulariser in the form of elastic cored wire is lower than the cost of the FeSiMg5 master alloys.
EN
The results of studies on the use of magnesium alloy in modern cored wire injection method for production of nodular and vermicular graphite cast irons were described. The injection of Mg cored wire length is a treatment method which can be used to process high sulphur cupola iron held in ladles or iron melted in an electric induction furnace. This paper describes the results of using a high-magnesium ferrosilicon alloy in cored wire (Mg recovery 47-70% ) for the production of vermicular and nodular graphite cast irons at Ścinawka Foundry, and for the production of nodular graphite iron at the following foundries: GZUT, KRAKODLEW, Centrozap - DEFKA, EE Zawiercie, WSK-Rzeszów, FWM PRZYSUCHA, HSW Stalowa Wola and PIOMA. The results of calculations and experiments have indicated the length of the cored wire to be injected basing on the initial sulfur content and weight of the treated melt. The results of numerous trials have shown that the magnesium cored wire process can produce high quality nodular and vermicular graphite irons under the specific industrial conditions of the above mentioned foundries. It has also been proved that in the manufacture of nodular graphite iron, the cost of the nodulariser in the form of elastic cored wire is lower than the cost of the FeSiMg or NiCuMg master alloys.
9
Content available remote Określenie własności mechanicznych żeliwa sferoidalnego metodą ATD
PL
W artykule przedstawiono sposób oceny jakości żeliwa sferoidalnego gatunku ZsCu1.0 w oparciu o metodę ATD. Przedstawiono krzywe ATD, dla których wyznaczono punkty charakterystyczne i w oparciu o nie dokonano oceny jakości żeliwa.
EN
The paper presented equation of regression for evaluation of quality of ductile cast iron of sort ZsCu1.0. They were prepared with the use of characteristic points of TDA curves.
PL
W pracy przedstawiono wyniki badań strukturalnych żeliwa hartowanego izotermicznie w złożu fluidalnym jedno- i dwustopniowo oraz badań uzupełniających własności mechanicznych i struktury żeliwa hartowanego dwustopniowo w stopionej cynie i oleju. Analiza pierwszych umożliwiła wyjaśnienie przyczyn niepowodzenia dwustopniowego hartowania izotermicznego w złożu fluidalnym. Wyniki badań żeliwa hartowanego dwustopniowo w ciekłej cynie i oleju potwierdziły przewidywania odnośnie do możliwości oddziaływania na własności plastyczne żeliwa ADI na drodze dwustopniowego hartowania izotermicznego.
EN
In this part the results of structure investigations of ductile iron after one-step and two- step fluid-bed austempering are presented. Moreover, the results of additional experiment, enclosing tensile testing and structure observations of two-stage austempering in molten tin and hot oil are included. The analysis of the first allowed to explain the failure of two-stage austempering in fluid bed bath. The results of investigations of two-stage austempering in molten tin and then in hot oil proved the theoretical anticipations concerning the possibility to influence of two-stage austempering on the elongation of ADI.
11
Content available remote Kompleksowa ocena jakości żeliwa sferoidalnego
PL
W pracy przedstawiono ocenę jakości żeliwa sferoidalnego w oparciu o przeprowadzone badania kompleksowe dwóch gatunków żeliw. Przedstawiono równania regresji do oceny jakości żeliwa sferoidalnego gatunku ZsCul. Opracowano je na podstawie charakterystycznych punktów krzywych ATD. Do opisu kształtu wydzieleń grafitu zastosowano współczynnik kształtu C.
EN
The paper presented equations of regression for evaluation of graphite shape in nodular cast iron. They were prepared with the use of characteristic points of TDA curves. The factor shape C was used to describe the nodular cast iron.
PL
W artykule przedstawiono badania nad oceną jakości żeliwa sferoidalnego w oparciu o analizę wielkości wydzieleń grafitu. Wytopy żeliwa sferoidalnego przeprowadzono w warunkach przemysłowych. Ocenę własności mechanicznych żeliwa przedstawiono w formie równań regresji.
EN
The paper describes the study of ductile cast iron for evaluation of quality. The investigations were carried out on the Powen S.A. Zabrze. The investigations determine a relationship between the area of graphite separations and mechanical properties.
13
Content available remote Metoda ATD jako sposób oceny stopnia sferoidyzacji żeliwa sferoidalnego
PL
W artykule przedstawiono sposób oceny stopnia sferoidyzacji grafitu w oparciu o metodę ATD. Ocenę stopnia sferoidyzacji przedstawiono w formie równań regresji, w których zostały ujęte punkty charakterystyczne krzywych ATD. Do opisu kształtu wydzieleń grafitu zastosowano współczynnik kształtu C.
EN
The paper presented equations of regression for evaluation of graphite shape in nodular cast iron. They were prepared with the use of characteristic points of TDA curves. The factor shape C was used to describe the nodular cast iron.
14
Content available remote Metoda ATD jako sposób oceny jakości żeliwa sferoidalnego gatunku EN-GJS-400-15
PL
W artykule przedstawiono sposób oceny jakości żeliwa sferoidalnego gatunku EN-GJS-400-15 w oparciu o metodę ATD. Przedstawiono krzywe ATD, dla których wyznaczono punkty charakterystyczne i w oparciu o nie dokonano oceny jakości żeliwa.
EN
The paper presented equations of regression for evaluation of quality of ductile cast iron of sort EN GJS-400-15. They were prepared with the use of characteristic points of TDA curves.
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