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1

Uszlachetnianie przemysłowych stopów ALSi w zespolonej obróbce rafinacji barbotażowej

Zych Jerzy S., Janus Arkadiusz, Smorawiński Zdzisław

Przegląd Odlewnictwa

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2022

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Vol. 72, nr 5-6

248--255

PL

W pracy przedstawiono wyniki badań złożonej rafinacji stopów AISi. W testach modelowych z użyciem wody jako medium wykonano badań porównawcze trzech przemysłowych rotorów stosowanych w obróbce barbotażowej obejmującej rafinację gazową wspomaganą rafinacja z użyciem soli. Obróbka solami w większości rozwiązań prowadzona jest metodą wprowadzania rozdrobnionych soli w głąb leja (wiru). Wykazano, iż podczas celowo wytwarzanego w ciekłym medium leja wokół osi rotora pojawią się podciśnienie dochodzące do wartości 20 mm(H2). Pobocznym skutkiem tego zjawiska jest zasysanie cieczy (wody/metalu) z górnych warstw i szybki transport tej cieczy w głąb kąpieli. W testach porównawczych wykazano, iż konstrukcja głowic rotora ma duży wpływ na poziom powstającego podciśnienia. W każdym wypadku zwiększanie szybkości obrotowej prowadzi do zwiększenia wartości podciśnienia. Transport cieczy (metalu) z górnych warstw w kadzi/zbiorniku prowadzi do wtórnego zanieczyszczenia kąpieli tlenkami pływającymi po powierzchni. Obecność tych trąceń wykazano w teście PODFA, wykonanym w realnych przemysłowych warunkach. W pracy wykazano, iż najbardziej korzystnym rozwiązaniem w złożonej rafinacji barbotażowej jest transport soli rafinującej kanałem wykonanym osi i głowicy rotora. W tym rozwiązaniu nie ma potrzeby wytwarzania technologicznego leja dla wprowadzenia soli rafinujących.

EN

Results of investigations of the complex refining of AlSi alloys are presented in the hereby paper. Comparative investigations of three industrial rotors applied in the degassing process using a rotating head, consisting of a gaseous refining supported by a salt refining, were performed using water as a medium. Treatment by salts, in most solutions, is carried out by an introduction of disintegrated salts deep inside a vortex. It was shown that during the intentionally formed vortex the negative pressure, reaching up to 20 mm(H2), occurs in a liquid medium around the rotor axis. The side effect of this phenomenon is the liquid (water/metal) drawing in from upper layers and its fast transport into the bath depth. It was proved, in comparative tests, that the rotor head structure has a significant influence on the negative pressure level. In each case, increasing of the rotation speed leads to the increase of the negative pressure. Transportation of a liquid (metal) from its upper layers, in a ladle/container, causes secondary contaminations of the bath by oxides floating on its surface. Presence of these inclusions was indicated by the PODFA tests performed under real industrial conditions. It was shown in this study that the most favorable solution in the complex degassing process is the transport of refining salts via the channel constructed in the axis and head of the rotor, since in this solution there is no need of making the technological vortex for introducing of refining salts.

2

Evaluating the Attenuation in Ultrasonic Testing of Castings

Boháčik M., Mičian M., Sládek A.

Archives of Foundry Engineering

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2018

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Vol. 18, iss. 2

151--156

EN

This paper considers the assessment of attenuation in aluminium alloys castings and in cast iron prepared by gravity casting method and by casting under pressure. The issue of ultrasound attenuation is important in setting the conditions of non-destructive (NDT) testing, especially in casted materials. The characteristics of the ultrasonic technique and ultrasonic attenuation and the calculation of the attenuation and the velocity of ultrasound are presented in the theoretical part of this paper. For experimental measurements, cylindrical castings from AlSi alloy (a hypoeutectic alloy with a silicon content of about 7% - AlSi7 and a eutectic alloy with a silicon content of about 12% - AlSi12) and from grey and ductile cast iron were made. The ultrasonic records of the casting control, the calculation of ultrasound attenuation for individual samples are listed and described in the experimental part. The evaluation of measurements and comparison of calculated ultrasound attenuation is at the end of this article.

3

Examples of new models applied in selected simulation systems with respect to database

Ignaszak Z., Hajkowski J., Popielarski P.

Archives of Foundry Engineering

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2013

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Vol. 13, iss. 1

45--50

EN

The tolerance of damage rule progressively meets the approval in the design casting parts procedures. Therefore, there were appeared the new challenges and expectations for permanent development of process virtualization in the mechanical engineering industry. Virtualization is increasingly developed on the stage of product design and materials technologies optimization. Increasing expectations of design and process engineers regarding the practical effectiveness of applied simulation systems with new proposed up-grades modules is observed. The purpose is to obtain simulation tools allowing the most possible realistic prognosis of the casting structure, including indication, with the highest possible probability, places in the casting that are endangered with the possibility of shrinkage– and gas porosity formation. This 3D map of discontinuities and structure transformed in local mechanical characteristics are used to calculate the local stresses and safety factors. The needs of tolerance of damage and new approach to evaluate the quality of such prognosis must be defined. These problems of validation of new models/modules used to predict the shrinkage– and gas porosity including the chosen structure parameters in the example of AlSi7 alloy are discussed in the paper.

4

Statistical analysis using multiple regression of stereological parameters for skeleton castings microstructure

Cholewa M., Dziuba-Kałuża M.

Archives of Foundry Engineering

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2011

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Vol. 11, iss. 3 spec.

43--48

EN

In this article authors showed influence of technological parameters and modification treatment on structural properties for closed skeleton castings. Approach obtained maximal refinement of structure and minimal structure diversification. Skeleton castings were manufactured in accordance with elaborated production technology. Experimental castings were manufactured in variables technological conditions: range of pouring temperature 953÷1013 K , temperature of mould 293÷373 K and height of gating system above casting level 105÷175 mm. Analysis of metallographic specimens and quantitative analysis of silicon crystals and secondary dendrite-arm spacing analysis of solution α were performed. Average values of stereological parameters for all castings were determined. (B/L) and (P/A) factors were determined. On basis results of microstructural analysis authors compares research of samples. The aim of analysis was selected samples on least diversification of refinement degree of structure and least silicon crystals. On basis microstructural analysis authors state that samples 5 (AlSi11, Tpour 1013K, Tmould 333K, h – 265 mm) has the best structural properties (least diversification of refinement degree of structure and the least refinement of silicon crystals). Then statistical analysis results of structural analysis was obtained. On basis statistical analysis autors state that the best structural properties for technological parameters: Tpour = 1013 K, Tmould = 373 K and h = 230 mm [4]. The results of statistical analysis are the prerequisite for optimization studies.

5

Analiza wybranych właściwości strukturalnych i wytrzymałościowych aluminiowych odlewów szkieletowych

Cholewa M., Dziuba-Kałuża M.

Archiwum Technologii Maszyn i Automatyzacji

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2009

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Vol. 29, nr 3

13-21

PL

W artykule przedstawiono geometrię przykładowego szkieletu i rdzenia opartą na osiemnasto-ścianie „hydraulicznym" oraz technologie wykonania rdzenia. Opracowano warunki technologiczne wytwarzania zamkniętych odlewów szkieletowych ze stopów AISi. Celem badań była analiza stopnia rozdrobnienia i jednorodności struktury odlewów szkieletowych oraz właściwości użytkowych tych odlewów. W związku z tym zmierzono odległości gałęzi drugorzędowych dendrytów (DAS) w charakterystycznych obszarach wykonanych odlewów. W badanych odlewach odległości wtórnych osi dendrytów DAS roztworu a osiągają najmniejsze wartości w obszarze stanowiącym geometryczne naroże ścian zewnętrznych zamykających odlew próbny, aczkolwiek są to wartości zbliżone do wartości we wszystkich charakterystycznych obszarach. Zbadano wytrzymałość na ściskanie próbek z odlewów szkieletowych. Największą wartość tej wytrzymałości uzyskano dla odlewu wykonanego przy parametrach technologicznych ujmujących temperaturę zalewania, temperaturę formy oraz wysokość układu wlewowego, a mianowicie: T/iń = 1013 K, T(ormy = 333 K, h = 265 mm. Opracowane warunki technologiczne umożliwiają wytworzenie odlewów o wymaganej zewnętrznej i wewnętrznej postaci geometrycznej i korzystnych właściwościach strukturalnych i wytrzymałościowych.

EN

In this paper geometry of skeleton casting and the core was shown together with its technology. Manufacturing parameters were determined for production of closed skeleton castings made of AISi alloys. The main aim was to analyze the refinement degree of the microstructure and its homogeneity together with operational properties of the castings. Dendrite arm spacing (DAS) was observed in characteristic regions of the casting. For studied castings the lowest values of DAS were observed in the corner of external walls of the casting. Nevertheless, values observed are close to those observed in other characteristic regions. To evaluate the mechanical properties compression test were performed. The highest compression strength was observed for skeleton casting manufactured under following technological conditions: pouring temperature 1013 K, mould temperature 333 K, height of the gating system 265 mm. Determined technological conditions enabled manufacturing of skeleton castings with desired external and internal geometry and favorable mechanical and structural properties.

6

Studies of structural and mechanical properties of aluminum skeleton castings

Cholewa M., Dziuba-Kałuża M.

Archives of Foundry Engineering

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2009

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Vol. 9, iss. 3

29-34

EN

Skeleton castings were manufactured in accordance to elaborated production technology. The subject of the research was the microstructural analysis of non - monolithic castings. Analysis of metallographic specimens and quantitative analysis of silicon crystals and secondary dendrite-arm spacing analysis of solution \alfa were performed. Studies were executed for typical regions of skeleton castings. The regions were diversified regarding the cooling rate. The greatest value of compression strength were observed for casting manufactured according to technological conditions: pouring temperature Tpour 1013 K, temperature of the mould Tmould 333 K and height of the gating system h - 265 mm. Technological conditions and modification treatment were determined on base of advantageous structural properties (high homogeneity and refinement). On basis of the research authors confirmed that in applied conditions of solidification advantageous structure of AlSi11 alloy was obtained. The article showed the method of structure design of AlSi11 alloys skeleton castings, which was essential to obtain favorable operating properties of skeleton castings in future technical applications.

7

Prediction of useful casting structure applying Cellular Automaton method

Ignaszak Z., Hajkowski J., Hajkowski M.

Archives of Foundry Engineering

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2009

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Vol. 9, iss. 3

61-66

EN

The results of simulation investigations of primary casting's structure made of hypoeutectic Al-Si alloy using the Calcosoft system with CAFE 3D (Cellular Automaton Finite Element) module are presented. CAFE 3-D module let to predict the structure formation of complete castings indicating the spatial distribution of columnar and equiaxed grains. That simplified model concerns only hypoeutectic phase. Simulation investigations of structure concern the useful casting of camshaft which solidified in high-insulation mould with properly chills distribution. These conditions let to apply the expedient locally different simplified the grains blocs geometry which are called by the authors as pseudo-crystals. The mechanical properties in selected cross-sections of casing are estimated.

8

Closed aluminium skeleton casting

Cholewa M., Dziuba-Kałuża M.

Archives of Foundry Engineering

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2008

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Vol. 8, iss. 1 spec.

53--56

EN

In this article authors showed method for manufacturing of skeleton castings with continuous external surface. Wall thickness of the external surface was 6 mm. The experimental casting was manufactured in order to verify the results of filling mould cavity which were obtained by numerical simulation. The aluminosilicate core was used to produce experimental aluminum skeleton castings with dimensions of (115x65x136) mm. Experimental casting was manufactured with elevated temperature of mould (370 K). Lower and stotted ingate with high geting system (300mm) was used. Analysis of ability of metal to fill the mould cavity in establish technological conditions was perfomed. Degree of refinement of structure in typicall region of skeleton casting was compared. Qualitative different degree of fineness of eutectic was confirmed. Selection of modification conditions AlSi alloy of skeleton casting is necessary. The manufacturing of skeleton casting in establish technological conditions enables obtained very good filling of mould cavity and suitable external geometrical form of casting.

9

Wpływ modyfikacji na strukturę i morfologię przełomów siluminu AISi7

Romankiewicz F., Romankiewicz R.

Archiwum Odlewnictwa

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2004

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R. 4, nr 14

438-443

PL

Przedstawiono wyniki badań nad modyfikacją siluminu AISi7 dodatkami AlSr10 i AIB4.

EN

The results of the modification of alloy AISi7 by the additives of AISriO and AIB4 have been presented.

10

Numeryczna symulacja tiksotropowego wypełniania formy stopem AlSi.

Sołek K., Wajda W., Pietrzyk M., Mitura Z., Białobrzeski A.

Rudy i Metale Nieżelazne

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2001

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R. 46, nr 11

579-583

PL

Priorytetowym zadaniem niniejszej pracy jest opis poprawnego mechanizmu wypełniania formy oraz odpowiedni dobór reologii półciekłego metalu. Przeprowadzono analizę proponowanych w literaturze naukowej modeli ciał odkształconych w warunkach tiksotropowych. W dalszej kolejności przeprowadzono pilotażowe symulacje formowania skomplikowanego kształtu programem Forge2 (R). W symulacji założono model ciała lepko-plastycznego opisanego równaniem Nortona-Hoffa. Wybrane wyniki przedstawiono w formie pól prędkości odkształcenia i naprężeń. Podjęto zatem próbę weryfikacji uzyskanych wyników symulacji z wynikami doświadczalnymi.

EN

The objective of this work is description of the mechanism of die filling and verification of the selection of rheology of metal in semi-solid state. The most important theoretical models taken from literature are discussed. Next the preliminary simulation of net-shape forming is presented. The software Forge2 (R) with the viscoplastic Norton-Hoff constitutive model was used in the simulation. The results of computing are shown in the form of velocity and strain fields. The comparison of the simulation and experiment allowed validation of the model.

11

Stront jako modyfikator stopów AlSi i AlSiCu.

Łatkowski A., Bronicki M., Gryziecki J.

Rudy i Metale Nieżelazne

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1999

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R. 44, nr 3

101-107

PL

Opierając się na analizie zmian mikrostruktury określono optymalne ilości strontu zapewniające efekt modyfikacji w stopach AK7, AK9, AK11, AK52 i AK 104. Zbadano również trwałość modyfikatora poprzez kolejne przetopy odlewów. Przeprowadzono badania wpływu ilości modyfikatora na udarność stopów.

EN

The optimum strontium amount for good modification of AK7, AK9, AK11, AK52, AK104 alloys was determined on the base of the analysis of microstructural changes. The stability of the modifier was investigated on the way of succesive remelting of billets. The influence of amount of modifier on the impact strength of the alloys was established.