Vpliv vrste krožne litine na strjevanje zlitine AlSi10Mg(Fe)

Štucin, Jan (author), Vončina, Maja (mentor)

Reciklaža aluminijevih sekundarnih surovin je energijsko in finančno ugodnejša kot pridobivanje primarnega aluminija, saj pri pretaljevanju porabimo samo okoli 5 % celotne energije, kot bi jo sicer potrebovali za proizvodnjo primarnega aluminija. To je tudi razlog, da se zadnjih nekaj desetletjih količina recikliranega materiala močno veča, trenutno pa je kar tretjina vseh aluminijevih izdelkov narejenih z uporabo sekundarnih surovin. Kljub številnim prednostim recikliranja pa je uporaba krožne litine za izdelavo kvalitetnih zlitin zahteven proces, pri katerem se pozornost posveča predvsem zagotavljanju ustrezne kemijske sestave s čim manj vključkov in nečistoč. Z namenom analize vpliva vrste krožne litina na potek strjevanja zlitine AlSi10Mg(Fe) smo izdelali štiri eksperimentalne vzorce. Prvi vzorec je bil sestavljen samo iz ingota zlitine AlSi10Mg(Fe), ostali vzorci pa so bili sestavljeni iz ingota ter določene vrste krožne litine v razmerju 1:1. Vrste krožne litine, ki smo jih uporabili pri izdelavi eksperimentalnih vzorcev, so bili izmetni ulitki, ostanek litine v livni votlini in elementi ulivnih sistemov. Najprej smo vzorce pretalili in s pomočjo enostavne termične analize posneli ohlajevalne krivulje. Iz ohlajevalnih krivulj smo določili karakteristične temperature strjevanja in jih okarakterizirali. Na vseh eksperimentalnih vzorcih smo opravili kemijsko analizo in iz dobljenih rezultatov s programom ThermoCalc simulirali potek ravnotežnega in neravnotežnega strjevanja ter izračunali ravnotežni fazni diagram. Rezultate enostavne termične analize in ravnotežne izračune smo nato primerjali in analizirali vpliv vrste krožne litine na potek strjevanja zlitine AlSi10Mg(Fe). Diferenčno vrstično kalorimetrijo smo uporabili za določitev talilne in strjevalne entalpije, pri čemer smo tudi potrdili premenske temperature med taljenjem in strjevanjem vzorcev. Mikrostrukturo preiskovanih vzorcev smo analizirali s pomočjo optičnega mikroskopa, kjer smo se osredotočili predvsem na obliko, porazdelitev in količino mikrostrukturnih sestavin.

• Language: Slovenian
• Keywords: Zlitina AlSi10Mg(Fe), krožna litina, ravnotežno in neravnotežno strjevanje, termična analiza, diferenčna vrstična kalorimetrija, mikrostruktura
• Work type: Bachelor thesis/paper
• Organization: NTF - Faculty of Natural Sciences and Engineering
• Year: 2018
• PID: 20.500.12556/RUL-101677
• COBISS.SI-ID: 1732447
• Publication date in RUL: 24.06.2018

ŠTUCIN, Jan, 2018, Vpliv vrste krožne litine na strjevanje zlitine AlSi10Mg(Fe) [online]. Bachelor’s thesis. [Accessed 18 March 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=101677

Secondary language

• Language: English
• Title: Influence of scrap revert type on solidification of AlSi10Mg(Fe) alloy

Abstract

Recycling of secondary aluminium alloys is energetically and financially more favorable than the production of primary aluminium, whereas only about 5 % of the total energy is consumed when recycling in comparison with energy consumed for the production of primary aluminium. This is also the reason that the amount of recycled aluminium has increased over the past few decades, and currently about one third of all aluminium products are made by using secondary alloys. Despite numerous advantages of aluminium recycling, the use of aluminium scrap revert for the production of high-quality alloys is a demanding process, whereas the attention is primarily paid to ensuring adequate chemical composition with as few inclusions and impurities as possible. In order to analyze the influence of different aluminium scrap revert types on solidification of AlSi10Mg(Fe) alloy, we made four experimental samples. The first sample was made only from AlSi10Mg(Fe) alloy ingot, while the other samples were made from an ingot and different scrap revert type in a ratio of 1:1. The types of scrap revert that we used in the production of experimental samples were scrap castings, casting residue in a casting cavity and elements of casting systems. Firstly, we melted the samples and recorded the cooling curve using simple thermal analysis. We determined and characterized the characteristic solidification temperatures from the cooling curve. On all experimental samples we made chemical analysis, from which the results were used for simulation of the equilibrium and non-equilibrium solidification course using ThermoCalc program. Furthermore, we also calculated the equilibrium phase diagrams. We compared the results of the simple thermal analysis and equilibrium calculations and analyzed the influence of the scrap revert types on the solidification course of AlSi10Mg(Fe) alloy. With differential scanning calorimetry we determined the melting and cooling enthalpy, whereby we also confirmed the characteristic temperatures during melting and solidification of the samples. We analyzed the microstructure of the experimental samples with optical microscope, focusing primarily on the shape, distribution and amount of microstructural components.

• Keywords: AlSi10Mg(Fe) alloy, scrap revert, equilibrium and non-equilibrium solidification, thermal analysis, differential scanning calorimetry, microstructure