Vpliv varjenja s trenjem in mešanjem raznorodnih zlitin na zaostale napetosti ter natezno trdnost

Strle, Gašper (author), Trdan, Uroš (mentor), Klobčar, Damjan (comentor)

Aluminijeve (Al) zlitine so kot konstrukcijski material nepogrešljive v transportni industriji. Predvsem zaradi ugodnega razmerja med trdnostjo in maso. Tehnologija spajanja s trenjem in mešanjem namerava zamenjati obstoječo tehnologijo (kovičene spoje), predvsem zaradi kakovostnejših spojev in preprostejše izvedbe. Po končanem varjenju se zaradi vnesene energije generirajo zaostale napetosti, ki so posledica mikrostrukturnih in toplotnih sprememb. V diplomskem delu smo ugotavljali vpliv omenjenega spajanja na zaostale napetosti in mehanske lastnosti. Izmerjene rezultate smo primerjali na različnih mestih spoja, tj. oddaljenosti od začetka varjenja. V prvi fazi smo s postopkom trenja in mešanja spojili plošči raznorodnih aluminijevih zlitin (2017A-T451 in 7075-T651). Nato smo pred ter po izrezu nateznih epruvet z vodnim curkom vzdolž temena spoja v prečni smeri na zvar izmerili zaostale napetosti. S tem smo preučili vplive različnega vnosa energije na danih mestih. Natezne epruvete smo potrgali s trgalnim strojem in analizirali mehanske lastnosti. Ugotovili smo korelacijo med tlačnimi napetostmi na temenu zvarnega spoja, generiranih med postopkom varjenja ter natezno trdnostjo zvarnega spoja. Ob tem smo dosegli najvišjo natezno trdnost pri epruveti, ki je bila izrezana v sredini zvarnega spoja, kjer so bili pogoji.

• Language: Slovenian
• Keywords: varjenje s trenjem in mešanjem (FSW), aluminijeve zlitine, zaostale napetosti, rentgenska difrakcija (XRD), natezni preizkus
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: FS - Faculty of Mechanical Engineering
• Place of publishing: Ljubljana
• Publisher: [G. Strle]
• Year: 2019
• Number of pages: XIII, [40] f.
• PID: 20.500.12556/RUL-106867
• UDC: 621.791:669.715(043.2)
• COBISS.SI-ID: 16566555
• Publication date in RUL: 22.03.2019

STRLE, Gašper, 2019, Vpliv varjenja s trenjem in mešanjem raznorodnih zlitin na zaostale napetosti ter natezno trdnost [online]. Bachelor’s thesis. Ljubljana : G. Strle. [Accessed 25 April 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=106867

Secondary language

• Language: English
• Title: Effect of friction stir welding process of dissimilar alloys on residual stress and tensile strength

Abstract

Aluminum alloys are indispensable as a structural material in all branches of the transport industry. Their advantage over other metals is a favorable weight-to-strength ratio. Therefore, a new solid-state joining technology, friction stir welding intends to replace the existing technology (riveted joints) in the future. Mainly due to better weld quality and method simplicity. Due to the energy input during welding process, residual stresses are generated as consequence of microstructural and thermal modification. In the thesis, we wanted to figure out the effect of the mentioned welding technique on the residual stresses and mechanical properties of the welded joint. Measurements were compared at different weld zones, i.e. distance from the beginning of welding. At first, two plates of dissimilar aluminum alloys (2017A-T451 and 7075-T651) were joined by the method of friction stir welding. Then, before and after cutting-out specimens with water jet technology, we measured residual stresses in the transverse direction along the welding face. Our purpose was to study the effect of the energy input in different zones. Mechanical properties were measured using standard tensile specimens.We found the correlation between the compressive stresses on the face of the welded joint generated during the welding process and the tensile strength of the welded joint. Also, the highest tensile strength has been achieved at the specimen, which was cut out from the middle of the weld joint. There were the most optimal conditions.

• Keywords: friction stir welding (FSW), aluminum alloys, residual stresses, X-ray diffraction (XRD), tensile test