magistrsko delo
Rok Steinacher (Author), Maja Vončina (Mentor)

Abstract

Proces udrobnjevanja je ena izmed glavnih praks v livarnah pri litju aluminijevih zlitin. Z njim zmanjšujemo velikost kristalnih zrn ?-Al. Zmanjševanje kristalnih zrn ?-Al poteka na različne načine, najpogostejši je z dodajanjem predzlitin oz. udrobnjevalcev vrste Al-Ti-B v talino. Cilj magistrskega dela je bil, kako na enostaven in hkrati zanesljiv način preveriti učinkovitost udrobnjevalcev. Z ustreznim dodatkom udrobnjevalcev, v našem primeru AlTi3B1, v talino vnesemo kali za heterogeno nukleacijo primarnih kristalov ?-Al. Za zagotavljanje ustrezne velikosti kristalnih zrn ?-Al pod 200 µm sta zelo pomembni kakovost in učinkovitost dobavljenih udrobnjevalcev, ki se lahko od dobave do dobave razlikujejo. V literaturi lahko zasledimo standardno metodo TP1 za določevanje učinkovitosti udrobnjevalcev, ki pa je za industrijske aplikacije zahtevna. Zato je bil cilj, razviti enostavno metodo za določevanje učinkovitosti udrobnjevalcev, ki se bo uporabljala pri rednih kakovostnih pregledih udrobnjevalcev v industrijskem okolju. Tako smo razvili metodo, kjer se primarni aluminij z ustreznim dodatkom udrobnjevalca ulije v jekleni »ring«, ki je položen na ognjevarni izolacijski material. Po strjevanju se izvede mikrostrukturna analiza zrnatosti v skladu s standardom ASTM 112-96. Vzporedno smo z enako količino dodanega udrobnjevalca k primarnemu aluminiju izvedli še standardno TP1 metodo. Tako smo dobili povezavo med našo in standardno metodo za določitev učinkovitosti udrobnjevalca, s katero bomo lahko primerjali učinkovitost dobavljenih udrobnjevalcev.

Keywords

predzlitina AlTi3B1;udrobnjevanje;metoda »ring« test;standardna metoda TP1;velikost kristalnih zrn α-Al;

Data

Language: Slovenian
Year of publishing:
Typology: 2.09 - Master's Thesis
Organization: UL NTF - Faculty of Natural Sciences and Engineering
Publisher: [R. Steinacher]
UDC: 669
COBISS: 132345091 Link will open in a new window
Views: 79
Downloads: 11
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Other data

Secondary language: English
Secondary title: new method development for determining grain-refiners effectiveness
Secondary abstract: The grain refining process is one of the main practices of casthouses when casting aluminium alloys, which reduces the size of α-Al crystal grains. The reduction of α-Al crystal grains is takes place in different way, of which the most common practice is adding master alloys or grain refiners of type Al-Ti-B into the melt. The aim of the master thesis was to find a way to check the effectiveness of grain refiners in a simple and at the same time reliable way. With the appropriate addition of grain refiners, in our case AlTi3B1, seeds are introduced into the melt for heterogeneous nucleation of primary α-Al crystal grains. The quality and efficiency of delivered grain refiners, which may vary from delivery to delivery, are very important to ensure an adequate α-Al crystal grain size below 200 µm. In the literature, we can find the standard method TP1 for determining the efficiency of the grain refiners, but it is demanding for industrial applications. Therefore, the goal was to develop a simple method for determining the effectiveness of grain refiners to be used in regular quality inspections of grain refiners in an industrial environment. We have developed a method where primary aluminium is cast with the appropriate addition of grain refiners into a steel "ring" which is placed on a fireproof insulating material. After solidification, a microstructural grain analysis is performed in accordance with the ASTM 112-96 standard. In parallel, the standard TP1 method was also performed for the same amount of added grain refiners to the primary aluminium. Thus, we have obtained a link between our method and the standard method for determining the efficiency of the grain refiners, with which we will be able to compare the efficiency of the supplied grain refiners.
Secondary keywords: master alloy AlTi3B1;grain refining;method »ring« test;standard TP1 method;α-Al crystal grain size;
Type (COBISS): Master's thesis/paper
Study programme: 0
Embargo end date (OpenAIRE): 1970-01-01
Thesis comment: Univ. v Ljubljani, Naravoslovnotehniška fak., Oddelek za materiale in metalurgijo
Pages: XVI, 60 f.
ID: 16401010