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1

Iron Intermetallic Phases in the Alloy Based on Al-Si-Mg by Applying Manganese

Podprocka R., Bolibruchova D.

Archives of Foundry Engineering

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2017

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Vol. 17, iss. 3

217--221

EN

Manganese is an effective element used for the modification of needle intermetallic phases in Al-Si alloy. These particles seriously degrade mechanical characteristics of the alloy and promote the formation of porosity. By adding manganese the particles are being excluded in more compact shape of “Chinese script” or skeletal form, which are less initiative to cracks as Al5FeSi phase. In the present article, AlSi7Mg0.3 aluminium foundry alloy with several manganese content were studied. The alloy was controlled pollution for achieve higher iron content (about 0.7 wt. % Fe). The manganese were added in amount of 0.2 wt. %, 0.6 wt. %, 1.0 wt. % and 1.4 wt. %. The influence of the alloying element on the process of crystallization of intermetallic phases were compared to microstructural observations. The results indicate that increasing manganese content (> 0.2 wt. % Mn) lead to increase the temperature of solidification iron rich phase (TAl5FeSi) and reduction this particles. The temperature of nucleation Al-Si eutectic increase with higher manganese content also. At adding 1.4 wt. % Mn grain refinement and skeleton particles were observed.

2

Usable Properties of AlSi7Mg Alloy after Sodium or Strontium Modification

Tupaj M., Orłowicz A. W., Mróz M., Trytek M., Markowska O.

Archives of Foundry Engineering

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2016

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Vol. 16, iss. 3

129--132

EN

The paper deals with the effect of microstructure diversified by means of variable cooling rate on service properties of AlSi7Mg cast alloy refined traditionally with Dursalit EG 281, grain refining with titanium-boron and modified with sodium and a variant of the same alloy barbotage-refined with argon and simultaneously grain refining with titanium-boron and modified with strontium. For both alloy variants, the castings were subject to T6 thermal treatment (solution heat treatment and artificial aging). It turned out that AlSi7Mg alloy after simultaneous barbotage refining with argon and grain refining with titanium-boron and modified with strontium was characterised with lower values of representative microstructure parameters (SDAS – secondary dendrite arm spacing, λE, lmax) and lower value of the porosity ratio compared to the alloy refined traditionally with Dursalit EG 281 and grain refining with titanium-boron and modified with sodium. The higher values of mechanical properties and fatigue strength parameters were obtained for the alloy simultaneously barbotage-refined with argon and grain refining with titanium-boron and modified with strontium.

3

Relation between Porosity and Mechanical Properties of Al-Si Alloys Produced by Low- Pressure Casting

Cais J., Weiss V., Svobodova J.

Archives of Foundry Engineering

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2014

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Vol. 14, iss. 1 spec.

97--102

EN

The aim of the research was to evaluate influence of porosity size on mechanical properties of AlSi7Mg0.3 (EN AC 42 100) alloy before and after thermal treatment. The castings from the same production type (forms used for tires production) were used for the analysis. They were casted using low-pressure casting technology. Since the negative influence of porosity on mechanical properties of Al alloys is generally known that there is no quantitative assessment. The relation of porosity size in the structure of AlSi7Mg0.3 alloy and its mechanical properties is verified and quantified in this research. Static tensile testing has proven the relation between porosity size in a structure of an Al material and its mechanical properties. The image analysis was applied in quantitative measurement of the porosity. The measurement was performed on prepared metallographic specimens. Porosity size is considered as a fraction of pore area to the total area of the analyzed specimen and is taken in percentage. As far as the theoretical part of the issue the possible causes of porosity formation and its influence on particular Al alloy types are described [1, 2, 3].

4

Wpływ szybkości chłodzenia na parametr strukturalny λ2D modyfikowanego sodem stopu AlSi7Mg

Orłowicz A. W., Tupaj M., Mróz M.

Archives of Foundry Engineering

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2008

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Vol. 8, iss. 1 spec.

245--248

PL

Praca przedstawia wyniki badań wpływu szybkości chłodzenia stopu AlSi7Mg na jego mikrostrukturę. Celem pracy było ustalenie związku pomiędzy szybkością chłodzenia produkcyjnego stopu AlSi7Mg a wartością parametru strukturalnego λ2D. Badania wykonano na odlewach klinów wykonanych w masie formierskiej. U podstawy wnęki formy montowano ochładzalnik. Na podstawie badań stwierdzono, że zastosowanie ochładzalników pozwoliło uzyskać prawie ośmiokrotny wzrost szybkości chłodzenia w przypowierzchniowym obszarze odlewu. Stwierdzono, że wzrost szybkości chłodzenia stopu AlSi7Mg wpływa na zmniejszenie wartości parametru strukturalnego λ2D.

EN

Effect of cooling rate of hypoeutectic AlSi7Mg alloy on the casting microstructure are presented. The purpose of this study was an establish a relationship between cooling rate of production AlSi7Mg alloy and the structural parameter λ2D. Tests were carried out on wedge shaped castings with chills, made with sand mould. Based on the results of researches it was found that using of chills permit to increase of cooling rate about 8-times. The rising of cooling rate was found to permit a reduction of structural parameter λ2D.

5

Wpływ mieszanki egzotermicznej na bazie Na_{2}B_{4}O_{7} i NaNO_{3} na wytrzymałość na rozciąganie stopu AISi7Mg

Lipiński T.

Archiwum Odlewnictwa

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2006

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R. 6, nr 22

298-303

PL

Eksperyment prowadzono na stopie AlSi7Mg (PN-EN 1706) według planu czynnikowego 2{3} dla trzech zmiennych. Mieszankę egzotermiczną zestawiono z NaNO_{3}, Na_{2}B_{4}O_{7} i Mg (tab.1). Reduktor (Mg) obliczano w oparciu o reakcje chemiczną. Rezultaty zaprezentowano w postaci graficznej. Rysunki 2-7 przedstawiono dla dwóch poziomów zmiennych. Badania określiły wpływ mieszanki złożonej ze składników (tab. 1) na wytrzymałość na rozciąganie stopu AlSi7Mg.

EN

The experiments were conducted on alloy AISi7Mg, following a factor design 2{3} for 3 independent variabIes. Mixtures composed of NaNO_{3}, Na_{2}B_{4}O_{7}, and Mg were used for alloy treatment. The amount of a reducing agent (Mg) necessary to carry out the process was calculated on the basis of chemical reactions. The mass fraction (weight in weight concentration) of individual variabIes is presented in Table 1. Results of study present by graphical forms. Figures 2-7 present tensile strength (Rm) for each variable, at extreme (lower or higher) levels of the other two.