Utjecaj helija u zaštitnom plinu na oblik spoja pri zavarivanju aluminijevih legura AC MIG postupkom

master's thesis

• Title (english): Influence of helium in gas shielding on weld shape in AC MIG welding of aluminium alloys
• Author: Dominik Toma
• Mentor: Ivica Garašić (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2024-03-28, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering; Production Mechanical Engineering

Abstract

U radu se teoretski razmatraju aspekti zavarivanja aluminija, uključujući specifične izazove koji se pojavljuju pri zavarivanju ovog metala. Aluminij, iako je poznat po svojoj lakoći i otpornosti na koroziju, predstavlja posebne poteškoće tijekom zavarivanja zbog svoje visoke toplinske provodljivosti, sklonosti k formiranju oksidnog sloja i poroznosti u zavarenim spojevima. Ove poteškoće mogu utjecati na kvalitetu zavara i zahtijevaju posebne tehnike i postavke za efikasno zavarivanje. Razmatra se i uloga helija kao zaštitnog plina u procesu zavarivanja. Helij, kao zaštitni plin, igra značajnu ulogu zbog svojih jedinstvenih svojstava koja mogu značajno poboljšati kvalitetu zavara prilikom rada s aluminijem. Korištenje helija može rezultirati povećanjem toplinskog unosa, što dovodi do dublje penetracije i šireg zavara. Istražuje se AC MIG (Alternating Current Metal Inert Gas) metoda zavarivanja aluminija, koja omogućava bolje upravljanje toplinskim unosom i smanjenje formiranja oksida zahvaljujući izmjeničnom toku struje. Ova metoda pomaže u prevladavanju nekih od osnovnih izazova zavarivanja aluminija, pružajući čišće i kvalitetnije zavare.
U eksperimentalnom dijelu ovog rada prikazano je navarivanje koristeći aluminij 5083, koji je poznat po svojoj dobroj zavarljivosti i otpornosti na koroziju. U eksperimentu su detaljno analizirani kako različiti parametri zavarivanja, poput balansa polariteta i udjela helija u zaštitnom plinu, utječu na kvalitetu i geometriju navara. Nakon navarivanja izrađeni su makroizbrusci na kojima je analizirana geometrija navara u ovisnosti o balansu polariteta i udjelu helija u zaštitnom plinu. Prikazan je rezultat koliko značajno balans polariteta utječe na geometriju navara, te koliko udio helija povećava penetraciju i smanjuje utjecaj balansa polariteta.

Abstract (english)

The paper theoretically considers aspects of aluminum welding, including specific challenges that arise when welding this metal. Aluminum, known for its lightness and corrosion resistance, presents particular difficulties during welding due to its high thermal conductivity, tendency to form an oxide layer, and porosity in the welded joints. These difficulties can affect the quality of the welds and require special techniques and settings for efficient welding. The role of helium as a shielding gas in the welding process is also discussed. Helium, as a shielding gas, plays a significant role due to its unique properties that can significantly improve the quality of welds when working with aluminum. The use of helium can result in increased heat input, leading to deeper penetration and a wider weld. The AC MIG (Alternating Current Metal Inert Gas) method of aluminum welding is explored, which allows for better heat input management and reduction of oxide formation thanks to the alternating current flow. This method helps overcome some of the fundamental challenges of welding aluminum, providing cleaner and higher-quality welds.
In the experimental part of this work, build-up welding using aluminum 5083, known for its good weldability and corrosion resistance, is demonstrated. The experiment detailed how various welding parameters, such as EN ratio and the proportion of helium in the shielding gas, affect the quality and geometry of the build-up. After build-up welding, macro sections were prepared on which the geometry of the build-up was analyzed depending on the EN ratio and the proportion of helium in the shielding gas. The results show how significantly the EN ratio affects the geometry of the build-up, and how the proportion of helium increases penetration and reduces the impact of EN ratio.

• Keywords: aluminij; AC MIG; balans polariteta; helij
• Keywords (english): aluminium; AC MIG; EN ratio; helium
• Language: croatian
• URN:NBN: urn:nbn:hr:235:965291
• 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: 2024-03-27 07:30:09