diplomsko delo
Blaž Tršinar (Author), Goran Kugler (Mentor), Jakob Kraner (Co-mentor)

Abstract

Glavni cilj diplomskega dela je identificirati in kvantificirati ključne materialne parametre, ki igrajo odločilno vlogo pri razvoju mikrostrukture med procesom valjanja aluminijevih zlitin. Določitev teh parametrov je omogočila natančnejše prilagajanje vhodnih procesnih parametrov valjanja in posledično učinkovitejši nadzor razvoja mikrostrukture oziroma končnih lastnosti materiala. S tem je omogočeno izboljšanje mehanskih lastnosti industrijsko proizvedenih aluminijastih polizdelkov, ter povečana fleksibilnost in učinkovitost celotnega proizvodnega procesa. Diplomsko delo temelji na izvajanju numeričnih simulacij valjanja, ki so podprte z laboratorijskimi in industrijskimi meritvami ter mikrostrukturno karakterizacijo. Simulacijski model valjanja temelji na sklopitvi makroskopskega opisa procesa na osnovi mehanike kontinuuma z mikroskopskim modelom za napovedovanje razvoja mikrostrukture, ki temelji na teoriji povprečnega polja. Na osnovi procesnih parametrov oziroma predpisanih planov valjanja makroskopski model izračuna lokalni razvoj stopnje deformacije, temperature in hitrosti deformacije v izbranih točkah po preseku valjanca. Ti trije parametri za izbrane točke nato služijo kot vhodni podatki za simulacijo razvoja mikrostrukture. Mikrostrukturni model omogoča simulacijo razvoja celotne porazdelitve po velikosti kristalnih zrn, napetosti tečenja, akumulirane deformacije, stopnje mehčanja in proces statične rekristalizacije. Osrednji cilj diplomske naloge je primerjati in ovrednotiti simulirano mikrostrukturo z mikrostrukturo industrijsko valjanega traku v različnih fazah procesne verige vročega valjanja, tj. za lito stanje, stanje med vročim valjanjem in stanje po vročem valjanju za izbrano zlitino EN AW-6082. Simulacijski model za valjanje se je izkazal ustrezen za natančno napovedovanje povprečne velikosti kristalnih zrn, pri čemer so odstopanja med povprečnima velikostma simuliranih in industrijsko pridobljeni mikrostruktur manjša od 3,5 µm. Ključne spremenljivke, kot sta mobilnost velikokotnih kristalnih mej in verjetnost za nukleacijo pri statični rekristalizaciji, so bile identificirane kot kritične za doseganje ujemanja med simulacijami in industrijskimi rezultati. Dobljeni rezultati bodo prispevali k razvoju novih metod za optimizacijo proizvodnih procesov in izboljšanje kakovosti končnih izdelkov iz aluminijevih zlitin.

Keywords

vroče valjanje;simulacije razvoja mikrostrukture;EN AW-6082;plastična deformacija;statična rekristalizacija;

Data

Language: Slovenian
Year of publishing:
Typology: 2.11 - Undergraduate Thesis
Organization: UL NTF - Faculty of Natural Sciences and Engineering
Publisher: [B. Tršinar]
UDC: 669
COBISS: 212471811 Link will open in a new window
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Downloads: 696
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Other data

Secondary language: English
Secondary title: simulation of microstructure development for EN AW-6082 aluminium alloy during hot rolling
Secondary abstract: The main work of this thesis is to identify and quantify the key material parameters that play a decisive role in the development of microstructure during the rolling process of aluminum alloys. The determination of these parameters enabled more precise adjustments to the rolling process input parameters, leading to more effective control over the microstructural evolution and, consequently, the final properties of the material. This allows for the improvement of the mechanical properties of industrially produced aluminum semi-products, while also increasing the flexibility and efficiency of the entire production process. The thesis is based on performing numerical simulations of rolling, supported by laboratory and industrial measurements as well as microstructural characterization. The rolling simulation model is based on coupling the macroscopic description of the process, grounded in continuum mechanics, with a microscopic model for predicting microstructural evolution, which is based on mean-field theory. Using process parameters or predefined rolling schedules, the macroscopic model calculates the local evolution of strain, temperature, and strain rate at selected points across the cross-section of the rolled material. These three parameters for the selected points then serve as input data for the microstructural evolution simulation. The microstructural model enables the simulation of the complete grain size distribution, flow stress, accumulated strain, softening rate, and the process of static recrystallization. The central goal of this thesis is to compare and evaluate the simulated microstructure with the microstructure of industrially rolled strips at different stages of the hot rolling process, namely in the cast state, during hot rolling, and after hot rolling for the selected alloy EN AW-6082. The rolling simulation model has proven to be suitable for accurately predicting the average grain size, with deviations between the simulated and industrially obtained microstructures being less than 3.5 µm. Critical variables, such as the mobility of high-angle grain boundaries and the likelihood of nucleation during static recrystallization, were identified as essential for achieving consistency between simulations and industrial results. The findings will contribute to the development of new methods for optimizing production processes and improving the quality of final products made from aluminum alloys.
Secondary keywords: hot rolling;microstructure evolution simulations;EN AW-6082;plastic deformation;static recrystallization;
Type (COBISS): Bachelor 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: XIII, 34 f.
ID: 25161137