Utjecaj unosa topline pri MIG zavarivanju aluminijske legure 5083 i 6082 na mikrostrukturu zavarenog spoja

master's thesis

• Title (english): Infuence of the heat input during MIG welding of series 5083 and 6082 aluminium alloys on weld joint microstructure
• Author: Mia Sikora
• Mentor: Ivica Garašić (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2024-12-05, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering; Production Mechanical Engineering

Abstract

U teorijskom dijelu rada detaljno je opisana zavarljivost legura serija 5xxx i 6xxx gdje su
opisane neke od najčešćih pogrešaka koje se javljaju prilikom postupka zavarivanja legura
aluminija. Navedene su i opisane posljedice prevelikog unosa topline na mehanička svojstva.
Također, opisani i uspoređeni su postupci MIG zavarivanja impulsnim strujama pri čemu je
taljiva elektroda na pozitivnom polaritetu i MIG zavarivanja izmjeničnom strujom.
U eksperimentalnom dijelu rada provedeno je zavarivanje aluminijevih legura 5083 i 6082
postupcima DC MIG i AC MIG na više različitih debljina limova. Nakon zavarivanja
analizirane su mikrostrukture uzoraka s naglaskom na utjecaj topline na mikrostrukturu.
Također, na svjetlosnom mikroskopu analizirana je pojava nepravilnosti u metalu zavara.
Zaključno, određen je kemijski sastav zavarenog spoja te stupanj miješanja. Uočeno je kako se
unosom topline utječe na mikrostrukturu zavara, pa je uporabom AC MIG zavarivanja dobivena
grublja mikrostruktura s više nepravilnosti nego kod DC MIG postupka zavarivanja. Također,
AC MIG postupak rezultirao je nižim stupnjem miješanja u odnosu na DC MIG postupak.

Abstract (english)

In theoretical part of this thesis, the weldability of 5xxx and 6xxx series alloys are discussed,
addressing some of the most common defects that occur during the welding process. The
consequences of excessive heat input on mechanical properties are also explained. Additionally,
the MIG welding processes using pulsed currents with a consumable electrode on the positive
polarity and MIG welding with alternating current are described and compared.
In the experimental part of this thesis, welding of aluminum alloys 5083 and 6082 was
performed using DC MIG and AC MIG processes on various sheet thicknesses. After welding,
the microstructures of the samples were analyzed, focusing on the impact of heat on the
microstructure. Additionally, defects in the weld metal were examined using a light microscope.
Finally, the chemical composition of the weld joint and the degree of mixing were determined.
It was observed that the heat input affects the microstructure of the weld, with AC MIG welding
resulting in a coarse grained microstructure with more defects compared to the DC MIG
welding process. Additionally, the AC MIG process led to a lower degree of mixing compared
to the DC MIG process.

• Keywords: AC MIG; DC MIG; aluminijeve legure; unos topline; mikrostruktura
• Keywords (english): AC MIG; DC MIG; aluminium alloys; heat input; microstructure
• Language: croatian
• URN:NBN: urn:nbn:hr:235:808136
• Project: Number: IP-2022-10-9298; Title: Pouzdane metode za proračun aluminijskih konstrukcija koje odgovaraju zahtjevima budućnosti; Title: Reliable design methods for aluminium structures fit for the future requirements; Acronym: REAL-fit; Leader: Davor Skejić; Jurisdiction: Croatia; Funder: Hrvatska zaklada za znanost; Funding stream: Research Projects
• Study programme: Title: Mechanical Engineering; specializations in: Design, Process and Energy Engineering, Production Engineering, Engineering Modelling and Computer Simulation, Marine Engineering, Industrial Engineering and Management, Materials Engineering, Mechanics and Robotics, Autonomous Systems, Mechatronics and Robotics; Course: Production Engineering; Study programme type: university; Study level: graduate; Academic / professional title: sveučilišni/a magistar/magistra inženjer/inženjerka strojarstva (sveučilišni/a magistar/magistra inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Embargoed access; Embargo expiration date: 2026-12-05
• Public note: Ovaj rad je sufinancirala Hrvatska zaklada za znanost projektom HRZZ-IP-2022-10-9298 (REAL-fit: Pouzdane metode za proračun aluminijskih konstrukcija koje odgovaraju zahtjevima budućnosti, voditelj projekta Davor Skejić)
• Created on: 2024-12-01 18:16:01