Wyniki wyszukiwania - BazTech

1

ATD and DSC Analysis of IN-713C and ZhS6U-VI Superalloys

Binczyk F., Cwajna J., Gradoń P.

Archives of Foundry Engineering

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2017

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Vol. 17, iss. 1

13--16

EN

Paper presents the results of ATD and DSC analysis of two superalloys used in casting of aircraft engine parts. The main aim of the research was to obtain the solidification parameters, especially Tsol and Tliq, knowledge of which is important for proper selection of casting and heat treatment parameters. Assessment of the metallurgical quality (presence of impurities) of the feed ingots is also a very important step in production of castings. It was found that some of the feed ingots delivered by the superalloy producers are contaminated by oxides located in shrinkage defects. The ATD analysis allows for quite precise interpretation of first stages of solidification at which solid phases with low values of latent heat of solidification are formed from the liquid. Using DSC analysis it is possible to measure precisely the heat values accompanying the phase changes during cooling and heating which, with knowledge of phase composition, permits to calculate the enthalpy of formation of specific phases like γ or γ′.

2

Application of Modified Cores for Grain Refinement in Castings of Aircraft Turbine Blades

Binczyk F., Cwajna J., Gradoń P.

Archives of Foundry Engineering

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2017

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Vol. 17, iss. 3

19--22

EN

Paper presents the results of research on modified surface grain refinement method used in investment casting of hollow, thin-walled parts made of nickel based superalloys. In the current technology, the refining inoculant is applied to the surface of the wax pattern and then, it is transferred to the ceramic mould surface during dewaxing. Because of its chemical activity the inoculant may react with the liquid metal which can cause defects on the external surface of the cast part. The method proposed in the paper aims to reduce the risk of external surface defects by applying the grain refiner only to the ceramic core which shapes the internal surface of the hollow casting. In case of thin-walled parts the grain refinement effect is visible throughout the thickness of the walls. The method is meant to be used when internal surface finish is less important, like for example, aircraft engine turbine blades, where the hollowing of the cast is mainly used to lower the weight and aid in cooling during operation.

3

Influence of Modification and Casting Technology on Structure of IN-713C Superalloy Castings

Binczyk F., Cwajna J., Gradoń P., Mańka M.

Archives of Foundry Engineering

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2016

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Vol. 16, iss. 3

11--14

EN

The paper presents the results concerning impact of modification (volume and surface techniques), pouring temperature and mould temperature on stereological parameters of macrostructure in IN713C castings made using post-production scrap. The ability to adjust the grain size is one of the main issues in the manufacturing of different nickel superalloy castings used in aircraft engines. By increasing the grain size one can increase the mechanical properties, like diffusion creep resistance, in higher temperatures. The fine grained castings. on the other hand, have higher mechanical properties in lower temperatures and higher resistance to thermal fatigue. The test moulds used in this study, supplied by Pratt and Whitney Rzeszow, are ordinarily used to cast the samples for tensile stress testing. Volume modification was carried out using the patented filter containing cobalt aluminate. The macrostructure was described using the number of grains per mm2, mean grain surface area and shape index. Obtained results show strong relationship between the modification technique, pouring temperature and grain size. There was no significant impact of mould temperature on macrostructure.

4

Effect of the Annealing Temperature on the Microstructure and Properties of Ausferritic Nodular Cast Iron

Gumienny G., Klimek L., Kurowska B.

Archives of Foundry Engineering

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2016

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Vol. 16, iss. 3

43--48

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.

5

Casting of Titanium Alloys in Centrifugal Induction Furnaces

Karwiński A., Leśniewski W., Wieliczko P., Małysza M.

Archives of Metallurgy and Materials

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2014

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Vol. 59, iss. 1

403--406

EN

This paper discusses technical problems related with casting of titanium alloys in centrifugal vacuum furnaces. The potentials of an analysis of the centrifugal casting process carried out in the Flow3D software CFD (Computational Fluid Dynamics) were presented. Simulations were carried out on a model set, which enables casting of two connecting rods for an I.C. engine. Changes in the mould filling process were examined for the three selected spinning velocities of the casting arm. The ranges of the metal flow velocity in mould were calculated as well as metal pressure in mould after reaching a predetermined spinning velocity. The results and the adopted mould geometry enabled determination of the magnitude of stress occurring in mould at the time of filling it with liquid titanium alloy. The paper presents a methodology for testing of the ceramic material strength using a four-point loading arrangement. The strength of the ceramic material was determined on samples heated at different temperatures. The obtained results enabled a thesis to be formulated that for pouring of moulds in a centrifugal vacuum furnace, the layered foundry ceramic moulds can be safely used, and the use of moulds that will provide the directional solidification of metal should be possible as well.

PL

W artykule przedstawiono problemy techniczne związane z odlewaniem stopów tytanu w próżniowych piecach odśrodkowych. Zaprezentowano możliwości analizy procesu zalewania wirującej formy przeprowadzonej w programie Flow 3D CFD (Computational Fluid Dynamics). Obliczenia symulacyjne prowadzono dla zestawu modelowego umożliwiającego odlanie dwóch korbowodów silnika spalinowego. Analizowano zmiany sposobu wypełniania formy dla trzech wybranych prędkości wirowania ramienia odlewniczego. Obliczono zakresy prędkości przepływu metalu w formie oraz ciśnienia metalu występującego w formie po osiągnięciu założonej prędkości obrotowej. Uzyskane wyniki oraz przyjęta geometria formy pozwoliły na wyznaczenie wielkości naprężeń występujących w formie w momencie wypełnienia jej ciekłym stopem tytanu. Przedstawiono metodykę badania wytrzymałości materiału ceramicznego wykorzystującego czteropunktowy układ obciążający. Wyznaczono wytrzymałość materiału ceramicznego dla próbek wygizewanych w różnych temperaturach. Otrzymane wyniki pozwalają na przedstawienie tezy, że w podczas zalewania form w próżniowym piecu odśrodkowym będzie można bezpiecznie wykorzystywać warstwowe ceramiczne formy odlewnicze, oraz będzie możliwe zastosowanie form zapewniających założone kierunkowe krzepnięcie metalu.

6

The Relationship Between the Solidification Parameters and Chemical Composition of Nickel Superalloy IN-713C

Binczyk F., Gradoń J., Cwajna J., Szymszal J.

Archives of Foundry Engineering

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2014

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Vol. 14, iss. 4

5--10

EN

The paper presents the results of studies on the development of correlation of solidification parameters and chemical composition of nickel superalloy IN-713C, which is used i.a. on aircraft engine turbine blades. Previous test results indicate significant differences in solidification parameters of the alloy, especially the temperatures Tliq and Tsol for each batch of ingots supplied by the manufacturer. Knowledge of such a relationship has important practical significance, because of the ability to asses and correct the temperatures of casting and heat treatment of casts on the basis of chemical composition. Using the statistical analysis it was found that the temperature of the solidification beginning Tliq is mostly influenced by the addition of carbon (similar to iron alloys). The additions of Al and Nb have smaller but still significant impact. Other alloying components do not have significant effect on Tliq. The temperature Teut is mostly affected by Ni, Ti and Nb. The temperature Tsol is not in any direct correlation with the chemical composition, which is consistent with previous research. The temperature Tsol depends primarily on the presence of non-metallic inclusions present in feed materials and introduced during the melting and casting processes.

7

Investigation of an Advanced Cellulose Profile Used for the Manufacture of Gating Systems

Zawieja Z., Sawicki J., Gumienny G., Sobczyk-Guzenda A.

Archives of Foundry Engineering

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2014

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Vol. 14, iss. 3

123--128

EN

The here in paper contains the results of investigations on a new type of cellulose blend used for the manufacture of profiles applied in the process of making gating systems in the foundry industry. A standard cellulose profile was subjected to an experiment. During the experiment the profile was filled with a liquid cast iron and at the same time the temperatures of the liquid metal crystallizing inside the profile were measured as well as the temperature of the outer layer of the profile was controlled. Further, the microstructure of the cast iron, which crystallized out inside the cellulose profile, was analysed and the cellulose, thermally degraded after the experiment, was verified with the use of the chemical analysis method. Moreover, a quality analysis of the original as well as the degraded cellulose profile was run with the use of the FTIR infrared spectroscopy. The presented results revealed that the cellulose blend is aluminium silicate enriched and contains organic binder additives. The cast iron, which crystallized out, tended to have an equilibrium pearlitic structure with the release of graphite and carbides. The generation of disequilibrium ausferrite phases was also observed in the structure.

8

Effect of Temperature on Ausferritic Nodular Cast Iron Microstructure

Gumienny G., Klimek L.

Archives of Foundry Engineering

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2014

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Vol. 14, iss. 3 spec.

21--24

EN

The work presents the results of the studies of the effect of the temperature on the microstructure of ausferritic nodular cast iron. The ausferrite in the matrix was obtained by way of a specific combination of molybdenum and copper. The cast iron underwent annealing at the temperatures of 520, 550 and 580°C. The work presents the effect of the annealing temperature on the fraction of austenite in the cast iron matrix. The annealed and non-annealed cast iron hardness is given. The work also proves that an increase in the temperature up to 580°C causes a drop in the cast iron hardness.

9

Analysis of the Crystallization of AZ91 Alloy by Thermal and Derivative Analysis Method Intensively Cooled in Ceramic Shell

Rapiejko C., Pisarek B., Czekaj E., Pacyniak T.

Archives of Foundry Engineering

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2014

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Vol. 14, iss. 1

97--102

EN

The work presents the test result of the influence of cooling rate on the microstructure of AZ91 alloy, Vickers micro-hardness and Brinell hardness. Studies cooling and crystallization of AZ91 alloy was cast into the ceramic shells pre-heated to 180°C and then air-cooled at ambient temperature or intensively super cooled in the liquid coolant. The TDA method was applied to record and characterize the thermal effect resulting from the phase transformations occurring during the crystallization of AZ91 alloy. The kinetics and dynamics of the thermal processes of crystallization of AZ91 alloy in the ceramic shells were determined. Metallographic tests were performed with the use of an optical microscope. A comparison of these test results with the thermal effect recorded by way of the TDA method was made. Influence of cooling rate of AZ91 on HV0, 01 micro-hardness and Brinell hardness alloy was examined.

10

The technology of precision casting of titanium alloys by centrifugal process

Karwiński A., Leśniewski W., Pysz S., Wieliczko P.

Archives of Foundry Engineering

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2011

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Vol. 11, iss. 3

73-80

EN

The article describes the development of a procedure for the preparation of foundry ceramic moulds and making first test castings. The presented studies included: - development of technological parameters of the ceramic mould preparation process using water-based zirconium binders and zirconia ceramic materials, where moulds are next used for the centrifugal casting of titanium alloys melted in vacuum furnaces, - designing of pouring process using simulation software, - making test castings, - testing and control of the casting properties. The technological process described in this paper enables making castings in titanium alloys weighing up to about 500 g and used in the majority of technical applications.

11

Manufacturing technology of high-quality pressure castings

Pietrowski S., Pisarek B., Władysiak R.

Archives of Foundry Engineering

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2011

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Vol. 11, iss. 4

109-122

EN

The paper presents manufacturing technology of pressure castings made of Al-Si alloy without porosity or with low microporosity of castings. It has been shown that the greatest impact on the porosity of the castings and the concentration of hydrogen has had the charge to the melting furnace. Liquidation or occurrence of a small microporosity of castings provides refining with solid ref iners, nitrogen and modification of liquid alloy after various operations of preparing process. The liquid alloy stored in holding furnace should be refined once every 2 h with nitrogen. Authors developed a computer program of Al-Si alloys inspection with using of TDA method. The developed technology was verified under production conditions.

12

Heat transfer analysis during cooling of die with use of water mist

Władysiak R.

Archives of Foundry Engineering

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2011

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Vol. 11, iss. 3

167-174

EN

The paper presents the results of the heat transfer area during the cooling process of steel test die with water mist which consist the flow of air in the range 150-350 l/min and 0.05 0.24 l/min of water. Temperature change in the thickness of die by means showing with the thermal curves and the temperature gradient and temperature distribution in the space between the nozzle and the cooled surface of the metal mold using a thermal imaging camera and thermocouples measurement. The course of changes in the temperature gradient and the received heat flux from the die while cooling its with the flow of air and water mist stream. It has been shown that the use of water mist with a variable flow of air and water controls the process of heat transfer process between the permanent molds, and a stream of water mist.

13

Effect of additions of Cr, Mo, W and/or Si on the technological properties of aluminum-iron-nickel bronze

Pisarek B. P.

Archives of Foundry Engineering

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2011

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Vol. 11, iss. 3

199-208

EN

The aim of this study was to investigate the effect of additives of Cr, Mo, W and / or Si CuAll0Fe5Ni5 bronze, cast into sand moulds, the bronze technological properties such as: porosity, volumetric shrinkage Sv, linear shrinkage s and prone hot to cracking. The study relate to the newly developed grades aluminum-iron-nickel bronze, with additions of Cr, Mo, W and/or Si. In order to determine the technological properties of the test castings were made in the form of moulding sand, which made the mould cavities designed patterns. To evaluate the porosity and volumetric shrinkage was used for digital image analysis method. Volumetric shrinkage was determined using developed, the new method, the surface shrinkage Svp designation, and then converting it to the volumetric shrinkage, using prepared relation Sv=f(Djs)*Svp. It was found that made the bronze alloy additions to reduce the size of pores surface area of gas and shrinkage in the test bronze. The probability of microporosity with an area of 0.002560-0.120647 mm2 can be described by gamma distribution. Changing the chemical composition of the grades tested bronze strongly alter the first volumetric shrinkage Sv, and less to change the linear shrinkage s. The increase in gas porosity and shrink in bronze reduces the volumetric shrinkage and linear. The addition of Cr, Mo, W and/or Si to the bronze CuAll0Fe5Ni5 does not change its prone to hot cracking.

14

Water mist effect on cooling process of casting die and microstructure of AlSi9 alloy

Władysiak R.

Archives of Foundry Engineering

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2010

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Vol. 10, iss. 2

185--194

EN

The paper presents the results of crystallization and cooling process of silumin AlSi9 and temperature distribution in the wall of research casting dies made of cast iron and steel in the temperature range 650÷100 oC during casting of silumin using water mist cooling consisting with air compressed (0,3÷0,4 MPa) and water (0,35÷0,45 MPa). It’s shown the nature and rate of change of casting die temperature and the formation of the temperature gradient at the wall thickness in the axis of the nozzle cooling the outer surface of the wall of casting die. Using derivative curves and regression models were compared to the temporary and average speed of crystallization and cooling of the casting in the 75÷200 oC temperature range. The differences of microstructure resulting from a change in the type of casting die, wall thickness of casting and the use of cooling water mist. It has been shown that the use of water mist and the changing wall thickness of die and the casting cooled pointwise lets you control the crystallization process, microstructure and quality of the silumin casting.

15

Influence of the technology of melting and inoculation preliminary alloy AlBe5 on change of concentration of Al and microstructure of the bronze CuAl10Ni5Fe4

Pisarek B.

Archives of Foundry Engineering

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2010

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Vol. 10, iss. 2

127--134

EN

Examining was the aim of the work: influence of the permanent temperature 1300°C ± 15°C and changing time of isothermal holding in the range 0÷50 minutes on the melting loss of aluminum in the bronze CuAl10Ni5Fe4; the quantity the slag rafining - covering Unitop BA-1 (0÷1,5%) on the effectiveness of the protection of liquid bronze before the oxygenation, the quantity of the preliminary alloy - in-oculant AlBe5 (0÷1,0%) on the effective compensation melting loss of aluminum and time of isothermal holding on the effect of the in-oculation of the bronze and the comparison of the effectiveness of the inoculation of the bronze in furnace and in the form. Introduced investigations resulted from the study of the new grades of the Cu-Al-Fe-Ni bronze with additions singly or simultaneously Si, Cr, Mo and/or W, to melting which necessary it is for high temperature and comparatively long time isothermal holding indispensable to the occur of the process of diffusive dissolving the high-melting of the bronze components. High temperature and lengthening the time of isothermal holding the liquid bronze in casting furnace the melting loss of Al influences the growth. Addition the slag of covering-refining Unitop BA-1 in the quantity 1,5% the bronze protects before the melting loss of aluminum by the time of isothermal holding in the temperature 1300°C about 15 minutes. Addition of the preliminary alloy AlBe5 in the quantity 0,6% it assures the effective compensation of the aluminum which melting loss undergoes for the studied parameters of the melting. The effect of the inoculation of the bronze together with diminishes the preliminary alloy AlBe5 with lengthening the time of isothermal holding. Because of this, use of the method of introducing the preliminary alloy it is seems good solution on the inoculation of aluminum bronzes directly to form, unsensitive on the time of isothermal holding the bronze.

16

Water mist effect on cooling process and microstructure of silumin

Władysiak R.

Archives of Foundry Engineering

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2009

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Vol. 9, iss. 3

205-210

EN

The paper presents the results of the process of crystallization and cooling of the AlSi11 silumin and temperature distribution in the wall of iron and bronze research casting die in the temperature field of 750 to 100oC in casting of the silumin with use of water cooling mist in the air at a pressure of 0.30 to 0.40MPa and the water from 0.35 to 0.45MPa. Showing the nature and rate of change of temperature in die casting and the formation of temperature gradient on the thickness of the die casting wall in the direction of the nozzle surface of the outer wall of the cooling die casting. Using derivation curves and regression equations there has been compared: the mean and instantaneous rates of crystallization and cooling cast in values of 750 - 200oC. In addition, there are presented the differences arising from the microstructure change of the die's type and thickness of its walls, the thickness of cast and the fact of using cooling water mist. The conduct of the changes of the hardness of the cast as a result of the applied cooling method of the die casting. It has been shown that the use of water mist with a variability of the die's wall thickness in the cooling zone gives control of the crystallization process, microstructure and mechanical properties of the final silumin cast.

17

The thermal analysis and derivative bronzes cast to plaster moulds

Pisarek B., Pawlak M.

Archives of Foundry Engineering

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2009

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Vol. 9, iss. 3

159-168

EN

It plaster moulds gets casted the alloys of following metals: Al, Cu, Ag, Au in precise and artistic founding. The investigation of the crystallization of bronzes in hot plaster moulds the method of the thermal analysis and derivative (TDA) was not realized out so far. Probe TDAg and tripod enabling the execution of measurements on inductive casting machine INDUTHERM-VC 500D were designed for this technology especially. It was confirmed that one the method TDA can identify the crystallization process of the bronze in hot plaster moulds. The investigations of the superficial distribution of the concentration of elements in the microstructure of the studied grades of the bronze on X-ray microanalizer were conducted. It results that they be subject to in bronze CuSn10-C (B10) and the CuSn5Zn5Pb5-C (B555) of strong microsegregation from conducted investigations: Pb, Sn and Sb. The single separates of intermetallic phase \kappa was identified in the bronze B10 rich first of all in Zn, Sn, Sb and Fe, and two intermetallic phase, one rich were identified in the bronze B555 first of all in Zn, Sb, (Nor, Fe) and second rich in Sn, Sb, (Nor, Fe). The most homogeneous microstructure from the bronze CuAl10Fe5Ni5-C (BA1055) is characterizes among the studied grades of the bronze in the cast state.

18

Selection of the temperature of casting the bronzes to plaster moulds

Pisarek B., Pawlak M.

Archives of Foundry Engineering

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2009

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Vol. 9, iss. 4

203-208

EN

The results of the investigations of the process of solidification of the bronze CuSn5Zn5Pb5-C (B555) and CuSn10-C (B10) in the hot plaster mould show in the work. For four temperatures of casting: 1200 o C, 1180 o C, 1160 o C and 1140 o C was conducted the investi-gation: the size of contraction cavity, the fulfillment of the mould cavity formative the casts of test slats about the thickness: 4 mm, 0,8 mm and 0,5 mm. It was conducted the investigation the processes sets in the arrangement the cast-mould and X-ray analysis phase XRD of compound coming into being in indirect layer created among mould and cast in the result of the thermal decomposition of the anhydrite. It results that the temperature 1140 o C is the optimum temperature of casting the bronze to hot plaster mould from carried out investigations. The minimum thickness of the wall of the cast from the bronze B555 is 0.5 mm, and from the bronze B10 0.8 mm. The realization of casts about thinner walls is made difficult because of giving off formed gases in the result of the thermal decomposition of the anhydrite. The products of the decomposition of the anhydrite react with elements steps in the chemical composition of studied bronzes, create in the arrangement the cast-mould the indirect layer folded from: sulphites, sulphides, oxides and clean metals (Pb) or their compounds, especially Sn and Sb.

19

Plaster mould casting process of AlSi11 alloy

Władysiak R., Pawlak M.

Archives of Foundry Engineering

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2009

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Vol. 9, iss. 4

225-232

EN

The paper presents the results of the crystallization and cooling process of AlSi11 silumin in the plaster mould with TDA method and describes the impact of the preparation of plaster mould and liquid silumin on received microstructure and quality of casting. The effect of the pouring temperature of silumin on porosity and filling of mould cavity was investigated. The nature and rate of change of temperature in casting and the formation of the microstructure was shown by means thermal and derivative curves. Through the use of control samples in range of a thickness of 0.5 - 4 mm confirmed the possibility of obtaining thin-walled silumin castings in pre-heated before plaster moulds. It has been proved that changing the parameters of pre-treatment moulds of gypsum, the pouring temperature and modification of silumin you can control the crystallization process, obtained microstructure and properties Rm, RP02 and HB.

20

Influence of melting and filtration processes on the structure and mechanical properties of aluminum alloys

Dudyk M., Asłanowicz J., Ościłowski L.

Archives of Foundry Engineering

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2008

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Vol. 8, iss. 3

41-46

EN

In the article are presented the results of the study on the applied upgrading processes such as refining, modification and filtration of the near eutectics alloy EN AC- 44000, AlSi11, (AK11), cast into the chill. The upgrading processes applied to the said alloy caused, in comparison to the alloy which was not upgraded, significant differences in the shape of the crystallization curves, obtained in the graphic record of the ATD-AED method. It was demonstrated the existence of connections between the thermal and electric phenomena during solidification and crystallization of the studied silumin. The obtained results of the metallographic analysis showed the occurrence of the impurities within the alloy structure in the form of porosity and oxides following the metallurgical processing (in pig sows). The primary studies on microstructure of the cast ceramic filters have demonstrated the purposefulness of introduction of the filtration process to the technology of aluminum alloys manufacturing. The microstructures of the filters cast with the studied alloys illustrate the extent and deployment of the impurities retained (in the filter) during the process of samples casting for measurement of the mechanical strength properties. On the example of the near eutectics alloy AK11, it has been demonstrated, that in comparison to the refined alloy there is a possibility to obtain significant improvement of mechanical properties, and especially elongation A5 and impact strength KCV.