Karakterizacija dupleks strukture dobivene aditivnom proizvodnjom električnim lukom i žicom

master's thesis

• Title (english): Characterization of duplex structure obtained by wire arc additive manufacturing
• Author: Ante Lemezina
• Mentor: Vera Rede (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2021-12-16, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering; Production Mechanical Engineering

Abstract

Cilj ovog rada bio je odrediti optimalni režim toplinske obrade dupleks nehrđajućeg čelika dobivenog aditivnom proizvodnjom električnim lukom i žicom.
U eksperimentalnom dijelu rada provedena je kvalitativna i kvantitativna analiza mikrostrukture i mjerenje tvrdoće različitim opterećenjima (HV0,2, HV0,1, HV0,05 i HV0,02). Uzorci dupleks čelika bili su podvrgnuti različitim režimima toplinske obrade kako bi se vidio utjecaj pojedine toplinske obrade na mikrostrukturu i tvrdoću.
Rezultati ispitivanja pokazuju da provedene toplinske obrade utječu na mikrostrukturu i tvrdoću dupleks čelika. Toplinski obrađeni uzorci imaju viši volumni udio austenita od toplinski neobrađenog uzorka, a kod većine uzoraka udio austenita je viši u sredini nego uz stijenku navara. Toplinski obrađeni uzorci imaju nižu tvrdoću od toplinski neobrađenog uzorka bez obzira na opterećenje pri mjerenju. Kod nižih opterećenja veća su rasipanja rezultata izmjerenih tvrdoća.
Kod svih uzoraka uočena je značajna ovisnost tvrdoće o primijenjenom opterećenju. Tijek promjene tvrdoće s povećanjem opterećenja kod većine uzoraka podudaran je na rubu i sredini zida navara.

Abstract (english)

The aim of this work was to determine the optimal heat treatment regime of duplex stainless steel obtained by wire and arc additive manufacturing.
In the experimental part of the master thesis, qualitative and quantitative analysis of the microstructure and hardness measurements with different loads (HV0.2, HV0.1, HV0.05 and HV0.02) were performed.
Duplex steel samples were exposed to different heat treatment regimes to observe the impact of individual heat treatments on the microstructure and hardness.
The test results show that the performed heat treatments affect the microstructure and hardness of duplex steel. Heat-treated samples have a higher volume fraction of austenite than sample without heat-treatment, and in most samples the share of austenite is higher in the middle than along the welded wall. Heat-treated samples have a lower hardness than unheated sample regardless of the measurement load. At lower loads, the scatter of the results of the measured hardnesses is higher.
In all samples, the measured hardnesses were significantly depended on the load. The course of the change in hardness with increasing load in most samples coincided at the edge and in the middle of the welded wall.

• Keywords: dupleks nehrđajući čelici; aditivna proizvodnja; WAAM; tvrdoća
• Keywords (english): duplex stainless steel; additive manufacturing; WAAM; hardness
• Language: croatian
• URN:NBN: urn:nbn:hr:235:672194
• Study programme: Title: Mechanical Engineering; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka strojarstva (magistar/magistra inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2021-12-02 07:43:42