diplomsko delo
Sabina Trako (Author), Marjan Marinšek (Mentor)

Abstract

Namen diplomskega dela je bil prepoznati osnovne termične efekte z beleženjem likvidus in solidus temperatur, ter določiti optimalni program segrevanja in ohlajevanja pri beleženju DTA signalov nikelj – krom – železovih zlitin. Problematika določevanja karakterističnih temperatur, Tliq. se pojavlja pri zlitinskih sistemih z nizko vrednostjo latentne toplote, HL, predvsem pri strjevanju in s tem povezano histerezno detekcijo likvidus temperature. Za uspešno izdelavo posameznih vrst nikljevih zlitin je določitev likvidus temperature, Tliq., ključnega pomena. Na podlagi likvidus temperature se določijo posamezna temperaturna področja, kjer vršimo posamezne tehnološke operacije sekundarne metalurgije (kot je oksidacija, rafinacija, in podobno) in tudi nastavitev parametrov za kontinuirno ulivanje slabov. Vse našteto pa neposredno vpliva na kakovost izdelane zlitine. Zadnje predvsem v smislu kontrole razvoja lite strukture v obliki makro in mikro izcejanja izdelanih slabov (kot polprodukta) z neposrednim vplivom na preoblikovanost pri vročem valjanju končnih produktov (nekonsistentno utrjevanje, poprava, rekristalizacija). Na podlagi kemične analize na niklju bogatih zlitin v času industrijske izdelave smo s komercialnim programom za simuliranje termodinamskega ravnotežnega strjevanja (Thermo-Calc) izračunali ravnotežni potek strjevanja in izrisali potrebne ravnotežne fazne diagrame. Prav tako smo odvzete vzorce zlitin analizirali z enostavno termično analizo (ETA), pri čemer smo posneli ohlajevalne krivulje in iz njih določili karakteristične točke strjevanja. Z metodo diferenčne termične analize (DTA) pa smo potrdili potek taljenja in strjevanja in s tem določili temperaturni interval strjevanja. Mikrostrukturo vzorca smo analizirali z uporabo OM analize.

Keywords

nikljeve zlitine;likvidus temperatura;solidus temperatura;mikrostruktura;termična analiza;ETA;DTA;Thermo-Calc;diplomske naloge;

Data

Language: Slovenian
Year of publishing:
Typology: 2.11 - Undergraduate Thesis
Organization: UL FKKT - Faculty of Chemistry and Chemical Technology
Publisher: [S. Trako]
UDC: 669.245:543.57(043.2)
COBISS: 52239363 Link will open in a new window
Views: 332
Downloads: 69
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Other data

Secondary language: English
Secondary title: Determination of characteristic temperatures (liquidus and solidus) of nickel-chromium-iron alloys using DTA
Secondary abstract: The aim of this thesis is to identify the basic thermal effects by recording liquidus and solidus temperatures, and to determine the optimal heating and cooling program by recording DTA signals of nickel – chromium – iron alloys. The problem of determining the characteristic temperatures, Tliq. occurs in alloy systems with a low value of latent heat, HL, especially in solidification process and the associated hysteresis detection of liquidus temperature. For the successful production of specific types of nickel alloys, the determination of the liquidus temperature, Tliq. is essential since based on the liquidus temperature, individual temperature ranges where we perform individual technological operations of secondary metallurgy (such as oxidation, refining, etc.) as well as the settings of parameters for continuous casting of slabs are determined. All of the above-mentioned parameters directly affect the quality of the manufactured alloy. The latter mainly in terms of controlling the casted steel in the form of macro and micro secretions observable in the manufactured slabs (as an intermediate product) with a direct impact on the transformation during hot rolling of final products (inconsistent hardening, repair, recrystallization). Based on chemical analysis of nickel-rich alloys during industrial production we calculated the equilibrium solidification flow and developed the necessary equilibrium phase diagrams with a commercial program for simulating thermodynamic equilibrium solidification (Thermo-Calc). We also analyzed the alloy samples by simple thermal analysis (ETA) by recording the cooling curves and deriving the characteristic solidification points from the obtained data. With the method of differential thermal analysis (DTA) we confirmed the course of melting and solidification and thus determined the temperature interval of solidification. The microstructure of the sample was analyzed using OM analysis.
Secondary keywords: nickel alloys;liquidus temperature;solidus temperature;microstructure;
Type (COBISS): Bachelor thesis/paper
Study programme: 1000374
Embargo end date (OpenAIRE): 1970-01-01
Thesis comment: Univ. v Ljubljani, Fak. za kemijo in kemijsko tehnologijo, VSŠ Kemijska tehnologija
Pages: 49 str.
ID: 12559529