Reakcijska kinetika med staljenim aluminijem in orodnim jeklom z in brez zaščitne plasti : magistrsko delo

Avbelj, Luka (author), Vončina, Maja (mentor), Medved, Jože (co-mentor)

Namen magistrskega dela je bil analizirati vpliv orodnega jekla brez in z zaščitno plastjo na interakcijo med staljenim aluminijem in orodnim jeklom. Kinetiko tvorbe interakcijske plasti med staljenim aluminijem in orodnim jeklom smo raziskali z diferencialno vrstično kalorimetrijo (DSC), pri čemer so ti rezultati podali visokotemperaturno odpornost orodnega jekla brez in z zaščitno plastjo v stiku s staljeno aluminijevo zlitino AlSi9Cu3. Pri tem niso bili vključeni zunanji dejavniki, kot je erozija. Izvedli smo dva preizkusa in sicer smo v DSC napravo vstavili sendvič vzorcev, pri čemer je bil spodnji iz orodnega jekla brez in z zaščitno plastjo ter zgornji iz aluminijeve zlitine AlSi9Cu3. Po končanem preizkusu smo vzorce metalografsko preiskali in analizirali debeline in vrste interakcijskih plasti z uporabo svetlobne in vrstične elektronske mikroskopije. Za primerjavo in potrditev dobljenih rezultatov v laboratoriju smo analizirali tudi orodje iz proizvodnje, pri čemer smo izvedli mikrostrukturno analizo orodnega jekla (orodja) brez in z zaščitno plastjo pred uporabo in po končani življenjski dobi. Osredotočili smo se na površino orodnega jekla v stiku z aluminijevo talino in oceno hrapavosti površine, ter debelino zaščitne plasti. Istočasno smo analizirali tudi hrapavost na izdelkih na začetku, sredini in koncu življenjske dobe orodja. Glede na rezultate izvedenih analiz lahko zaključimo, da je zaščitna plast na vzorcu opravila svojo nalogo. V vzorcih brez zaščitne plasti se tvorita interakcijska in kompozitna plast, medtem ko do interakcije med orodnim jeklom z zaščitno plastjo in aluminijevo zlitino ni prišlo. Smiselnost uporabe zaščitne plasti se kaže tudi na hrapavosti izdelkov, pri čemer je ta skozi vso življenjsko dobo orodja z zaščitno plastjo ostajala približno enaka, medtem ko se je pri uporabi orodja brez zaščitne plasti s časom izrazito večala.

• Language: Slovenian
• Keywords: reakcijska kinetika, interakcija aluminij-jeklo, diferenčna vrstična kalorimetrija, mikrostruktura, zaščitna plast, hrapavost.
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: NTF - Faculty of Natural Sciences and Engineering
• Place of publishing: Ljubljana
• Publisher: [L. Avbelj]
• Year: 2022
• Number of pages: XV, 48 f.
• PID: 20.500.12556/RUL-139903
• UDC: 669
• COBISS.SI-ID: 126623747
• Publication date in RUL: 08.09.2022

Secondary language

• Language: English
• Title: Reaction kinetics between molten aluminium and tool steel with and without protective layer : master's thesis

Abstract

The aim of the Master thesis was to analyse the influence of tool steel without and with a protective layer on the interaction between molten aluminium and tool steel. The kinetics of the formation of the interaction layer between the molten aluminium and the tool steel was studied using differential scanning calorimetry (DSC). These results revealed the high temperature resistance of the tool steel without and with protective layer in contact with the aluminium melt AlSi9Cu3. External factors such as erosion were not considered. Two tests were performed by placing a sandwich of specimens in the DSC machine, the lower one made of tool steel without and with protective coating and the upper one made of AlSi9Cu3 aluminium alloy. After the test, the samples were examined metallographically by analysing the thickness and type of the interacting layers using optical and scanning electron microscopy. In order to compare and validate the results obtained in the laboratory, we also analysed the tool from production and performed a microstructure analysis of the tool steel with and without a protective layer before and after the end of its service life. The surface of the tool steel in contact with the molten aluminium was analysed, focusing on the evaluation of the surface roughness and the thickness of the protective layer. In addition, the roughness of the products at the beginning, middle and end of the tool life was analysed. From the results of the analyses performed, we conclude that the protective layer on the sample has done its job. In the case of specimens without a protective layer, an interaction and a composite layer are formed, while the interaction between the tool steel with a protective layer and the aluminium alloy did not occur. The usefulness of using a protective coating is also reflected in the roughness of the products, which remained about the same throughout the life of the tool with a protective coating, while it increased significantly over time when the tool without a protective coating was used.

• Keywords: reaction kinetics, aluminium-steel interaction, differential scanning calorimetry, microstructure, protective layer, roughness.