Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 68

Liczba wyników na stronie
first rewind previous Strona / 4 next fast forward last
Wyniki wyszukiwania
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 4 next fast forward last
1
Content available Compacted Graphite Iron with the Addition of Tin
EN
The paper presents the effect of tin on the crystallization process, microstructure and hardness of cast iron with compacted (vermicular) graphite. The compacted graphite was obtained with the use of magnesium treatment process (Inmold technology). The lack of significant effect of tin on the temperature of the eutectic transformation has been demonstrated. On the other hand, a significant decrease in the eutectoid transformation temperature with increasing tin concentration has been shown. It was demonstrated that tin narrows the temperature range of the austenite transformation. The effect of tin on the microstructure of cast iron with compacted graphite considering casting wall thickness has been investigated and described. The carbide-forming effect of tin in thin-walled (3 mm) castings has been demonstrated. The nomograms describing the microstructure of compacted graphite iron versus tin concentration have been developed. The effect of tin on the hardness of cast iron was given.
EN
The paper presents the effect of manganese on the crystallization process, microstructure and selected properties: cast iron hardness as well as ferrite and pearlite microhardness. The compacted graphite was obtained by Inmold technology. The lack of significant effect on the temperature of the eutectic transformation was demonstrated. On the other hand, a significant reduction in the eutectoid transformation temperature with increasing manganese concentration has been shown. The effect of manganese on microstructure of cast iron with compacted graphite considering casting wall thickness was investigated and described. The nomograms describing the microstructure of compacted graphite iron versus manganese concentration were developed. The effect of manganese on the hardness of cast iron and microhardness of ferrite and pearlite were given.
PL
W pracy przedstawiono wyniki badań siluminu podeutektycznego z dodatkiem chromu przeznaczonego do odlewania pod ciśnieniem. W charakterze stopu wyjściowego zastosowano silumin o składzie chemicznym zbliżonym do siluminu gatunku EN AC-46000. W celu wprowadzenia chromu do siluminu wyjściowego zastosowano zaprawę AlCr15. Ilość siluminu wyjściowego oraz zaprawy AlCr15 dobrano w proporcjach pozwalających na uzyskanie w stopie zawartości Cr około 0,1; 0,2; 0,3; 0,4 i 0,5% wag. W ramach realizacji pracy zbadano zarówno silumin wyjściowy, jak również siluminy z dodatkiem chromu. Przedstawiono wyniki analizy termicznej i derywacyjnej ATD (ang. Differential Thermal Analysis – DTA), przeprowadzonej w celu zbadania procesu krystalizacji siluminów. Pokazano mikrostrukturę siluminów odlewanych do próbnika ATD oraz ciśnieniowo. Określono podstawowe właściwości mechaniczne siluminów odlewanych pod ciśnieniem. Przedstawione wyniki analizy ATD wykazały wpływ dodatku chromu na przebieg procesu krystalizacji badanego siluminu. Na krzywych ATD siluminu wyjściowego występują trzy efekty cieplne wywołane odpowiednio krystalizacją roztworu stałego α(Al), oraz dwóch eutektyk α + Al15(Fe,Mn)3Si2 + + β i α + Al2Cu + AlSiCuFeMnMgNi + β. Wprowadzenie chromu w ilości około 0,2% wag. spowodowało wystąpienie na krzywej derywacyjnej dodatkowego efektu cieplnego pochodzącego od krystalizacji fazy międzymetalicznej zawierającej chrom. Krystalizacja tej fazy zachodzi przed wydzielaniem się z cieczy dendrytów fazy α(Al). Analiza mikrostruktury siluminów odlewanych do próbnika ATD wykazała pojawienie się wydzieleń „nowej” fazy w siluminach zawierających 0,2% wag. lub więcej Cr. Wraz z pojawieniem się na krzywych ATD dodatkowego efektu cieplnego oraz „nowej” fazy w mikrostrukturze siluminu zauważono brak fazy Al15(Fe,Mn)3Si2. W siluminach odlewanych ciśnieniowo dodatek chromu również spowodował powstanie „nowej” fazy międzymetalicznej. Faza ta pojawia się przy zawartości około 0,3% wag. lub większej Cr. Ma ona morfologię zbliżoną do ścianowej. Wraz z podwyższaniem ilości chromu rozmiary tej fazy znacząco się zwiększają. Badania podstawowych właściwości mechanicznych siluminów odlewanych pod ciśnieniem wykazały, że dodatek Cr daje możliwość znaczącego podwyższenia głównie wytrzymałości na rozciąganie Rm i wydłużenia względnego A. Pierwiastek ten w mniejszym stopniu wpłynął na podwyższenie twardości HB. Wartości umownej granicy plastyczności Rp0,2 siluminu wyjściowego i siluminów z podwyższoną zawartością chromu nie zmieniają się istotnie. Najwyższe właściwości mechaniczne uzyskano dla siluminów zawierających około 0,2 i 0,3% wag. Cr.
EN
The paper presents the results of studies of hypoeutectic silumin with a chromium addition used for pressure casting. A silumin with the composition similar to that of EN AC-46000 was used as the initial one. In order to introduce chromium into the initial silumin, an AlCr15 master alloy was applied. The amounts of the initial silumin and the AlCr15 master alloy were selected in the proportions making it possible to obtain about 0.1; 0.2; 0.3; 0.4 and 0.5 wt. % of Cr in the alloy. Both the initial silumin and the silumins with the chromium addition were examined. The results of the thermal and derivational analysis performed to investigate the silumins' crystallization process have been presented. The microstructure of the silumins cast into an DTA tester and under pressure has been demonstrated. The basic mechanical properties of the pressure cast silumins have been presented. The results of the DTA analysis showed an effect of the chromium addition on the course of the crystallization process of the examined silumin. Three thermal effects are present on the silumin's DTA curves, caused by the crystallization of the solid solution α(Al), and of two eutectics α + Al15(Fe,Mn)3Si2 + β and α + Al2Cu + AlSiCuFeMnMgNi + + β. The introduction of chromium in the amount of about 0.2 wt. % caused the presence of an additional thermal effect on the derivation curve, originating from the crystallization of the intermetallic phase containing chromium. The crystallization of this phase occurs before the precipitation of the dendrites of phase α(Al) from the liquid. The microstructure analysis of the silumins cast into the DTA tester showed the presence of precipitations of a “new” phase in the silumins containing 0.2% wt. Cr or more. With the occurrence of an additional thermal effect on the DTA curves as well as the “new” phase in the silumin's microstructure, the lack of phase Al15(Fe,Mn)3Si2 was observed. In the pressure cast silumins, the chromium addition also caused the formation of a “new” intermetallic phase, which occurs with the Cr content of about 0.3 wt. % or more. Its morphology is similar to a faceted one. With an increase of the chromium content, the size of this phase significantly increases as well. The investigations of the basic mechanical properties of the pressure cast silumins showed that the Cr addition makes it possible to significantly increase mainly the tensile strength Rm and the unit elongation A. To a lesser extent, this element caused an increase of the hardness HB. The values of the proof stress Rp0.2 of the initial silumin and the silumins with an increased chromium content do not change significantly. The highest mechanical properties were obtained for the silumins containing about 0.2 and 0.3 wt. % Cr.
PL
W pracy przedstawiono wybrane zagadnienia z zakresu możliwości otrzymania ausferrytu w żeliwie sferoidalnym bez stosowania obróbki cieplnej odlewów. Osnowa ausferrytyczna zapewnia, poza wysokimi właściwościami mechanicznymi, wysoką odporność na zużycie ścierne i adhezyjne. Proponowana technologia zakłada modyfikację składu chemicznego, w wyniku której możliwe jest otrzymanie osnowy ausferrytycznej, przy studzeniu odlewów w formie. Grafit sferoidalny otrzymano w technologii Inmold. Do oceny procesu krystalizacji oraz przemiany w stanie stałym zastosowano analizę termiczną i derywacyjną (ATD). Przedstawiono badania wpływu wybranych dodatków stopowych dodawanych w różnych proporcjach na mikrostrukturę osnowy żeliwa. Wykazano możliwość otrzymania ausferrytu w odlewach z żeliwa sferoidalnego bez konieczności stosowania obróbki cieplnej. Zbadano odporność żeliwa na zużycie ścierne i adhezyjne.
EN
This study presents selected issues regarding the process of obtaining ausferrite from spheroidal cast iron without the application of thermal treatment to the casts. An ausferritic matrix, as well as strong mechanical properties, also ensures high abrasion and adhesion wear resistance. The proposed technology assumes that a change the chemical composition will take place, as a result of which it is possible to obtain an ausferritic matrix when the casts are cooled in the mould. Spheroidal graphite was obtained using Inmold technology. For the evaluation of the process of crystallization and transformation in the as-cast state, a thermal and derivational analysis (ATD) was carried out. Investigations of the effect of selected alloy additions in various proportions on the microstructure of the cast iron matrix were presented. It was demonstrated that it is possible to obtain ausferrite in spheroidal iron casts without the application of thermal treatment. The abrasion and adhesion wear resistance of cast iron was examined.
EN
The paper presents the results of the application of a statistical analysis to evaluate the effect of the chemical composition of the die casting Al-Si alloys on its basic mechanical properties. The examinations were performed on the hypoeutectic Al-Si alloy type EN AC-46000 and, created on its basis, a multi-component Al-Si alloy containing high-melting additions Cr, Mo, W and V. The additions were introduced into the base Al-Si alloy in different combinations and amounts (from 0,05% to 0,50%). The tensile strength Rm; the proof stress Rp0,2; the unit elongation A and the hardness HB of the examined Al-Si alloys were determined. The data analysis and the selection of Al-Si alloy samples without the Cr, Mo, W and V additions were presented; a database containing the independent variables (Al-Si alloy's chemical composition) and dependent variables (Rm; Rp0,2; A and HB) for all the considered variants of Al-Si alloy composition was constructed. Additionally, an analysis was made of the effect of the Al-Si alloy's component elements on the obtained mechanical properties, with a special consideration of the high-melting additions Cr, Mo, V and W. For the optimization of the content of these additions in the Al-Si alloy, the dependent variables were standardized and treated jointly. The statistical tools were mainly the multivariate backward stepwise regression and linear correlation analysis and the analysis of variance ANOVA. The statistical analysis showed that the most advantageous effect on the jointly treated mechanical properties is obtained with the amount of the Cr, Mo, V and W additions of 0,05 to 0,10%.
EN
The study presents the results of the application of a statistical analysis for the evaluation of the effect of high-melting additions introduced into a pressure cast Al-Si alloy on the obtained level of its proof stress Rp0.2. The base Al-Si alloy used for the tests was a typical alloy used for pressure casting grade EN AC-46000. The base alloy was enriched with high-melting additions, such as: Cr, Mo, V and W. The additions were introduced into the base Al-Si alloy in all the possible combinations. The content of the particular high-melting addition in the Al-Si alloy was within the scope of 0.05 to 0.50%. The investigations were performed on both the base alloy and alloy with the high-melting element additions. Within the implementation of the studies, the values of Rp0.2 were determined for all the considered chemical compositions of the Al-Si alloy. A database was created for the statistical analysis, containing the independent variables (chemical composition data) and dependent variables (examined Rp0.2 values). The performed statistical analysis aimed at determining whether the examined high-melting additions had a significant effect on the level of Rp0.2 of the Al-Si alloy as well as optimizing their contents in order to obtain the highest values of the Al-Si alloy's proof stress Rp0.2. The analyses showed that each considered high-melting addition introduced into the Al-Si alloy in a proper amount can cause an increase of the proof stress Rp0.2 of the alloy, and the optimal content of each examined high-melting addition in respect of the highest obtained value of Rp0.2 equals 0.05%.
EN
The results of statistical analysis applied in order to evaluate the effect of the high melting point elements to pressure die cast silumin on its tensile strength Rm, unit elongation A and HB were discussed. The base alloy was silumin with the chemical composition similar to EN-AC 46000. To this silumin, high melting point elements such as Cr, Mo, V and W were added. All possible combinations of the additives were used. The content of individual high melting point additives ranged from 0.05 to 0.50%. The tests were carried out on silumin with and without above mentioned elements. The values of Rm, A and HB were determined for all the examined chemical compositions of the silumin. The conducted statistical analysis showed that each of the examined high melting point additives added to the silumin in an appropriate amount could raise the values of Rm, A and HB. To obtain the high tensile strength of Rm = 291 MPa in the tested silumin, the best content of each of the additives should be in the range of 0.05-0.10%. To obtain the highest possible elongation A of about 6.0%, the best content of the additives should be as follows: chromium in the range of 0.05-0.15%, molybdenum 0.05% or 0.15%, vanadium 0.05% and tungsten 0.15%. To obtain the silumin with hardness of 117 HB, chromium, molybdenum and vanadium content should be equal to about 0.05%, and tungsten to about 0.5%.
8
Content available Copper in Ausferritic Compacted Graphite Iron
EN
This paper shows how it is possible to obtain an ausferrite in compacted graphite iron (CGI) without heat treatment of castings. Vermicular graphite in cast iron was obtained using Inmold technology. Molybdenum was used as alloying additive at a concentration from 1.6 to 1.7% and copper at a concentration from 1 to 3%. It was shown that ausferrite could be obtained in CGI through the addition of molybdenum and copper in castings with a wall thickness of 3, 6, 12 and 24 mm. Thereby the expensive heat treatment of castings was eliminated. The investigation focuses on the influence of copper on the crystallization temperature of the graphite eutectic mixture in cast iron with the compacted graphite. It has been shown that copper increases the eutectic crystallization temperature in CGI. It presents how this element influences ausferrite microhardness as well as the hardness of the tested iron alloy. It has been shown that above-mentioned properties increases with increasing the copper concentration.
PL
W niniejszej pracy przedstawiono wyniki badań siluminu z dodatkiem wanadu przeznaczonego do odlewania pod ciśnieniem. Jako stop wyjściowy zastosowano silumin podeutektyczny gatunku EN AC-46000. Do siluminu wyjściowego wprowadzano zaprawę AlV10 w ilości pozwalającej na uzyskanie zawartości wanadu w kolejno wytapianych siluminach po około 0,1; 0,2; 0,3; 0,4 i 0,5% wag. Badaniom poddano zarówno silumin wyjściowy, jak i siluminy zawierające wanad. Badania obejmowały analizę termiczną i derywacyjną (ATD) procesu krystalizacji, analizę metalograficzną mikrostruktury odlewów wykonanych w próbniku ATD i ciśnieniowych oraz określenie podstawowych właściwości mechanicznych siluminu odlewanego ciśnieniowo. Badania ATD wykazały wzrost temperatury początku krystalizacji siluminu oraz brak dodatkowych efektów cieplnych. Badania metalograficzne wykazały zmniejszenie średniej wielkości faz w mikrostrukturze stopu odlewanego do próbnika ATD. W siluminach zawierających 0,3; 0,4 i 0,5% wag. V zarówno płytkowe wydzielenia krzemu eutektycznego, jak i faz międzymetalicznych pochodzących z eutektyk charakteryzują się znacząco mniejszymi maksymalnymi wymiarami w porównaniu z siluminami o mniejszej zawartości V. W mikrostrukturze siluminów odlewanych pod ciśnieniem, które zawierają wanad powstają „nowe” fazy niewystępujące w siluminach niezawierających tego pierwiastka. Są to najprawdopodobniej fazy międzymetaliczne zawierające wanad. Wielkość wydzieleń tych faz rośnie wraz ze zwiększeniem zawartości wanadu w siluminie. Przeprowadzone badania podstawowych właściwości mechanicznych siluminów odlewanych pod ciśnieniem wykazały możliwość uzyskania większych wartości wytrzymałości na rozciąganie Rm, umownej granicy plastyczności Rp0,2 oraz twardości HB siluminów zawierających wanad w porównaniu z siluminami bez tego pierwiastka. Największe wartości: Rm = 248 MPa uzyskano w siluminie zawierającym około 0,3% wanadu; Rp0,2 = 113 MPa przy zawartości 0,1 i 0,2% oraz HB = 116 dla dodatku V około 0,2% wag. Względem siluminu bez dodatku V uzyskane wartości powodują podwyższenie Rm o 26%; Rp0,2 o 12% oraz HB o 7%.
EN
The paper presents the results of the study of Al-Si alloys with a vanadium addition used in pressure casting. The hypoeutectic Al-Si alloy grade EN AC-46000 was applied as the initial alloy. The master alloy AlV10 was introduced into the initial alloy in the amount making it possible to obtain the vanadium content in the consecutively melted Al-Si alloys of about 0.1; 0.2; 0.3; 0,4 and 0.5 wt. %. The tests were performed on both the initial Al-Si alloy and alloys containing vanadium. The investigations included a thermal and derivative (DTA) analysis of the crystallization process, a metallographic analysis of the microstructure of casts prepared in DTA tester and pressure casts, as well as the determination of the basic mechanical properties of the pressure cast Al-Si alloy. The DTA tests showed an increase in the temperature at the beginning of the Al-Si alloy crystallization and no additional thermal effects. The metallographic examinations demonstrated a decrease of the average phase size in the microstructure of the alloy cast in the DTA tester. In the Al-Si alloys containing 0.3; 0.4 and 0.5 wt. % V, both the lamellar precipitates of eutectic silicon and of the intermetallic phases originating in the eutectics were characterized by significantly lower maximal dimensions, compared to the Al-Si alloys with lower V contents. In the microstructure of the pressure cast Al-Si alloys, which contain vanadium, “new” phases may form, which did not occur in the Al-Si alloys without V. These are probably intermetallic phases containing vanadium. The size of these precipitates increases with the increase of the vanadium content in the Al-Si alloy. The performed tests of the basic mechanical properties of the pressure cast Al-Si alloys showed the possibility of obtaining higher values of tensile strength Rm, proof stress Rp0.2 and hardness HB of the Al-Si alloys containing vanadium, compared to the Al-Si alloys without this element. The highest values: Rm = 248 MPa were obtained in the Al-Si alloy containing about 0.3% vanadium; Rp0.2 = 113 MPa – with the content of 0.1, and 0.2% and HB = 116 for the V addition of about 0.2 wt. %. As regards the Al-Si alloy without a vanadium addition, the obtained values caused an increase of Rm by 26%; Rp0.2 by 12% and HB by 7%.
PL
W pracy analizowano wpływ dodatków Ni i Cu na właściwości mechaniczne żeliwa ADI w odlewach o różnej grubości ścianek. Zastosowano plan eksperymentu, stosując kombinacje dodatku Ni w ilości 0,5% i 1,5% oraz dodatku Cu w ilości 0,5% i 1,0%. Zawartość pozostałych pierwiastków wynosiła: C = 3,3−3,6%, Si = 2,2−2,6%, Mn = 0,10−0,13%, P do 0,05%, S do 0,020% (% wag.). Wykonano 4 wytopy żeliwa, odlewając wlewki o grubości 25 mm, 50 mm i 75 mm. Sferoidyzację żeliwa przeprowadzono metodą przewodu elastycznego (otoczka stalowa wypełniona magnezem). W formach odlewniczych zastosowano specjalny układ filtrująco-modyfikujący. Z każdego wytopu i z każdego wlewka wykonano próbki wytrzymałościowe. Po hartowaniu izotermicznym zmierzono Rm i A5. Opracowano wielomiany aproksymujące (Rm, A5) = f(Ni,Cu). Wielomiany te pozwalają na dobór optymalnych dodatków Ni i Cu dla uzyskania wymaganej wytrzymałości bądź plastyczności. Na podstawie wielomianów wykonano wykresy trójwymiarowe obrazujące powyższe zależności.
EN
The study analyzes the effect of Ni and Cu additions on the mechanical properties of ADI cast iron in casts with different wall thickness values. The applied experiment plan included the use of combinations of the Ni addition in the amount of 0.5% and 1.5% and the Cu addition in the amount of 0.5% and 1.0%. The content of the remaining elements equaled: C = 3 .3−3.6%, S i = 2 .2−2.6%, M n = 0 .10−0.13%, P max. 0.05%, S max. 0.020% (wt. %). Four cast iron melts were performed, by way of casting ingots with a thickness of 25 mm, 50 mm and 75 mm. The cast iron spheroidization was conducted by the flexible conduit method (steel envelope filled with magnesium). In the casting moulds, a special filtering-modifying system was applied. From each melt and each ingot, strength samples were prepared. After isothermal quenching, Rm and A5 were measured. The approximating polynomials (Rm, A5) = f(Ni,Cu) were elaborated. The polynomials make it possible to select the optimal Ni and Cu additions to obtain the required strength or plasticity. Based on the polynomials, three-dimensional diagrams illustrating the above relations were constructed.
11
Content available Nickel in Compacted Graphite Iron
EN
The paper presents results of the research work concerning effects of nickel concentration on the crystallization process, microstructure and selected properties of the compacted graphite iron. Compacted graphite in the cast iron was obtained with use of the Inmold process. The study has comprised the cast iron containing nickel up to concentration providing obtainment of austenitic microstructure of the matrix. The effect of the nickel on temperature of the eutectic crystallization was specified. It has been presented composition of the cast iron matrix in function of nickel concentration in a casting with wall thickness of 3 mm and 24 mm. Moreover, it has been presented conditions defining the possibility of obtaining an austenitic and martensitic compacted graphite iron. Effect of the nickel on hardness of the cast iron was described.
EN
Structural modification of hypoeutectic Al-Si alloy EN-AC 46000 alloy influences its microstructure and mechanical properties. In a series of examinations the EN-AC 46000 alloy has been doped with Cr, W and Mo. The study involved the differential thermal analysis (DTA) and the light microscopy structural analysis of the samples cut from pressure die castings and from samples cast into the DTA cup. The DTA and microstructure analyses revealed new phases in the alloy doped with mentioned additives. The strength properties measurements of the alloys doped with Cr, W and Mo showed significant improvement in tensile strength and elongation, while preserving good hardness.
EN
This paper presents the results of hypoeutectic 226 grade alloy as well as prepared on its basis Al-Si alloy containing Cr, V and Mo. The additives tested were added as AlCr15, AlV10 and AlMo8 master alloys. Alloys tested were poured into DTA sampler as well as using pressure die casting. An amount of Cr, V and Mo additives in alloy poured into DTA sampler comprised within the range approximately 0.05-0.35%. Alloys to pressure die casting contained 0.05-0.20% Cr, V and Mo. The crystallization process was examined using the derivative thermal analysis (DTA). The microstructure of castings made in the DTA sampler as well as castings made with use of pressure die casting were examined. The basic mechanical properties of castings made using pressure die casting were defined too. It has been shown in the DTA curves of Al-Si alloy containing approximately 0.30 and 0.35% Cr, Mo, and V there is an additional thermal effect probably caused by a peritectic crystallization of intermetallic phases containing the aforementioned additives. These phases have a morphology similar to the walled and a relatively large size. The analogous phases also occur in pressure die casting alloys containing 0.10% or more additions of Cr, V and Mo. The appearance of these phases in pressure die casting Al-Si alloys coincides with a decrease in the value of the tensile strength Rm and the elongation A. It has been shown die castings made of Al-Si alloys containing the aforementioned additives have a higher Rm and A than 226 alloy.
EN
The paper presents the results of the research on the effect of copper on the crystallization process, microstructure and selected properties of the compacted graphite iron. Compacted graphite in cast iron was obtained using Inmold process. The study involved the cast iron containing copper at a concentration up to approximately 4%. The effect of copper on the temperature of the eutectic crystallization as well as the temperature of start and finish of the austenite transformation was given. It has been shown that copper increases the maximum temperature of the eutectic transformation approximately by 5 oC per 1% Cu, and the temperature of the this transformation finish approximately by 8 o C per 1% Cu. This element decreases the temperature of the austenite transformation start approximately by 5 oC per 1% Cu, and the finish of this transformation approximately by 6oC per 1% Cu. It was found that in the microstructure of the compacted graphite iron containing about 3.8% Cu, there are still ferrite precipitations near the compacted graphite. The effect of copper on the hardness of cast iron and the pearlite microhardness was given. This stems from the high propensity to direct ferritization of this type of cast iron. It has been shown copper increases the hardness of compacted graphite iron both due to its pearlite forming action as well as because of the increase in the pearlite microhardness (up to approx. 3% Cu). The conducted studies have shown copper increases the hardness of the compacted graphite iron approximately by 35 HB per 1% Cu.
EN
This article presents the methodology for exploratory analysis of data from microstructural studies of compacted graphite iron to gain knowledge about the factors favouring the formation of ausferrite. The studies led to the development of rules to evaluate the content of ausferrite based on the chemical composition. Data mining methods have been used to generate regression models such as boosted trees, random forest, and piecewise regression models. The development of a stepwise regression modelling process on the iteratively limited sets enabled, on the one hand, the improvement of forecasting precision and, on the other, acquisition of deeper knowledge about the ausferrite formation. Repeated examination of the significance of the effect of various factors in different regression models has allowed identification of the most important variables influencing the ausferrite content in different ranges of the parameters variability.
PL
W niniejszym artykule przedstawiono wyniki badań siluminu podeutektycznego z dodatkiem molibdenu przeznaczonego do odlewania ciśnieniowego. Badania obejmowały analizę termiczną i derywacyjną procesu krystalizacji, analizę metalograficzną mikrostruktury odlewów wykonanych w próbniku ATD i ciśnieniowych oraz określenie podstawowych właściwości mechanicznych siluminu. Do badań przeznaczono silumin gatunku 226, który jest typowym siluminem do odlewania pod ciśnieniem. Do tego siluminu wprowadzano zaprawę AlMo8 w ilości pozwalającej na uzyskanie stężenia Mo w stopie po około 0,1; 0,2; 0,3; 0,4 i 0,5%. Badania procesu krystalizacji wykazały analogiczny przebieg krzywych ATD siluminu bez dodatku Mo oraz siluminów zawierających około 0,1; 0,2; 0,3 i 0,4% Mo. Wykazano zmianę w procesie krystalizacji badanego siluminu wywołaną zwiększeniem stężenia Mo do 0,5%. Zmiana ta polegała na wystąpieniu dodatkowego efektu cieplnego na krzywych ATD, który nie występował w siluminie bez dodatku Mo i siluminach o mniejszym jego stężeniu. W mikrostrukturze siluminu odlewanego do próbnika ATD zawierającego 0,3−0,5% Mo wystąpiły fazy, których nie obserwowano w stopach bez badanego dodatku i o mniejszym jego stężeniu. W odlewach ciśnieniowych fazy te wystąpiły we wszystkich badanych siluminach z dodatkiem Mo. Wymiary tych faz zwiększają się wraz ze wzrostem stężenia Mo w siluminie. Przeprowadzone badania podstawowych właściwości mechanicznych siluminów odlewanych pod ciśnieniem wykazały, że największą wartość wytrzymałości na rozciąganie Rm i wydłużenia względnego A uzyskano dla siluminu 226 z dodatkiem 0,4% Mo. Stanowi to wzrost Rm o 7,6% i A o 13,8% w ujęciu względnym w stosunku do siluminu 226 bez dodatku Mo. Największą wartość umownej granicy plastyczności Rp0,2 i twardości HB uzyskano dla siluminu 226 bez dodatku Mo.
EN
The article presents the results of studies of hypoeutectic silumin with a molybdenum addition used for pressure casting. The studies included a thermal-derivative analysis of the crystallization process, a metallographic analysis of the microstructure of casts made in a DTA tester and pressure casts, as well as the determination of the basic mechanical properties of the silumin. For the tests, silumin 226 was selected, which is a typical silumin for pressure casting. The AlMo8 master alloy was introduced into the silumin in an amount allowing the Mo concentration in the alloy to be about 0.1; 0.2; 0.3; 0.4 and 0.5%. The examination of the crystallization process showed an analogous course of the DTA curves of the silumin without the Mo addition and the silumins containing about 0.1; 0.2; 0.3 and 0.4% Mo. A change in the crystallization process of the examined silumin was established, caused by an increase of the Mo concentration to 0.5%. This change consisted in the occurrence of an additional thermal effect on the DTA curves, which did not take place in the silumin without the Mo addition or in the silumins with lower Mo concentrations. The microstructure of the silumin cast into the DTA tester with 0.3−0.5% Mo contained phases which were not observed in the alloys without the examined addition or with its lower concentrations. In the pressure casts, these phases were present in all the examined silumins with the Mo addition. The dimensions of these phases increase with the increase of the Mo concentration in the silumin. The performed studies of the basic mechanical properties of the silumins cast under pressure showed that the highest value of tensile strength Rm and unit elongation A were obtained for silumin 226 with the addition of 0.4% Mo. This constitutes an increase of Rm by 7.6% and of A by 13.8% in relative terms with respect to silumin 226 without the Mo adszczególdition. The highest values of yield strength Rp0.2 and hardness HB were obtained for silumin 226 without the Mo addition.
17
EN
Purpose: The paper presents results of the selected mechanical and tribological properties of the low friction MoS2(Ti,W) coatings with a Ti interlayer deposited by magnetron sputtering method on silumin. Design/methodology/approach: MoS2(Ti,W) coating was investigated by basic tribological tests and it was characterized by linear distribution analysis of selected chemical elements (EDS), nanohardness and Young’s modulus. Findings: It was established that the total thickness of the produced MoS2(Ti, W) coatings with the Ti layer equaled about 2.5 µm. The MoS2(Ti,W) layers produced on a substrate significantly increase its functional properties, by significantly lowering the friction coefficient and wear, thus improving its mechanical properties (hardness and Young’s modulus). Practical implications: Silumins used as a substrates should be previously refined before coating process to reduce the porosity of the material and to obtain maximum adherence of MoS2(Ti,W) layer. Originality/value: The increasingly accurate knowledge on the subject of the relations between the composition, processing, microstructure characteristics and properties has led to the improvement of aluminium properties. However, there is the need to improve of the tribological properties of these alloys what authors obtained.
EN
The basic aim of this study is to investigate the effect of vanadium and tungsten on the crystallization process, microstructure and mechanical properties of silumin grade EN-AC 46000. The research involved a derivative thermal analysis DTA of the crystallization process, the metallographic analysis as well as the mechanical properties. The metallographic analysis was carried out on pressure die castings and made in the DTA probe. Vanadium and tungsten were added simultaneously to silumin in amount of approximately 0.1; 0.2; 0.3 and 0.4%. The DTA studies have shown the similar shape of all crystallization curves. It has been shown the additives of vanadium and tungsten in pressure die cast silumin can significantly increase its tensile strength as an well as elongation.
EN
The paper presents the microstructure and selected properties of ausferritic nodular cast iron annealed at the temperature 520 and 550°C. This choice was dictated by the temperatures used in the practice of nitriding. Nodular graphite in cast iron was obtained with use of Inmold process. Cast iron containing molybdenum and copper ensuring obtaining an ausferrite in the cast iron matrix without the use of heat treatment of castings was tested. The effect of annealing temperature on the microstructure and the kind of fracture of the ausferritic nodular cast iron was presented. The effect of an annealing temperature on hardness, impact strength and the microhardness of ausferritic nodular cast iron matrix was shown too. The lamellar structure of phases in the cast iron matrix after annealing has been ascertained. There has been an increase in hardness of an annealed cast iron and microhardness of its matrix. The reduction in the impact strength of the cast iron annealed at 520 and 550°C was approximately 10-30%. Both an increase in the hardness of cast iron as well as an decrease in its impact strength is probably due to the separation of secondary carbides during the heat treatment.
EN
This article presents the results of studies in the hypoeutectic silumin destined for pressure die casting with the simultaneous addition of chromium and tungsten. The study involved the derivative and thermal analysis of the crystallization process, metallographic analysis and mechanical properties testing. Silumin 226 grade was destined for studies. It is a typical silumin to pressure die casting. AlCr15 and AlW8 preliminary alloys were added to silumin. Its quantity allowed to obtain 0.1, 0.2, 0.3 and 0.4% of Cr and W in the tested alloy. Studies of the crystallization process as well as the microstructure of the silumin poured into DTA sampler allowed to state the presence of additional phase containing 0.2% or more Cr and W. It has not occurred in silumin without the addition of above mentioned elements. It is probably the intermetallic phase containing Cr and W. DTA studies have shown this phase crystallizes at a higher temperature range than α (Al) solid solution. In the microstructure of each pressure die casting containing Cr and W the new phases formed. Mechanical properties tests have shown Cr and W additives in silumin in an appropriate amount may increase its tensile strength Rm (about 11%), the yield strength Rp0.2 (about 21%) and to a small extent elongation A.
first rewind previous Strona / 4 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.