Določevanje in analiza področja mešanja v enovarkovnih jeklenih navarih

Maček, Boštjan (author), Zorc, Borut (mentor)

V diplomskem delu se je analiziralo mešanje dodajnega in osnovnega materiala v enovarkovnih jeklenih navarih, ki so bili navarjeni z oplaščenimi elektrodami z različno vsebnostjo kroma in ogljika na pločevini iz konstrukcijskega jekla S355. Varilni parametri pred varjenjem vsakega navara so bili enaki, kar pomeni varjenje z enako dovedeno toploto z vsemi elektrodami in s tem merodajne pogoje za medsebojno primerjavo rezultatov. Stopnja primešanja osnovnega materiala v navar se je določala na tri načine: z geometrijsko metodo iz makropresekov, geometrijsko metodo z razmerji višin varka in računsko na osnovi primerjave z EDX metodo določene kemične sestave čistih navarov in enovarkovnih navarov. Z EDX metodo se je določila tudi širina delno premešanega področja in segregacije v transkristalnih zrnih navarov. Najnatančnejše so geometrijske metode določevanje stopnje primešanja. Vendar rezultati kažejo, da lahko z dovolj velikim številom analiziranih presekov v enem navaru in z dovolj velikim številom izvedenih analiz kemične sestave na teh presekih natančno ocenimo stopnjo primešanja osnovnega materiala tudi z EDX metodo.

• Language: Slovenian
• Keywords: oplaščena elektroda, enovarkovni navar, mešanje osnovnega in dodajnega materiala, določevanje stopnje mešanja, segregacije
• Work type: Bachelor thesis/paper
• Organization: NTF - Faculty of Natural Sciences and Engineering
• Year: 2019
• PID: 20.500.12556/RUL-111013
• COBISS.SI-ID: 1837919
• Publication date in RUL: 22.09.2019

Secondary language

• Language: English
• Title: Determination and analysis of a mixed zone in the one-layer steel surface welds

Abstract

In this diploma thesis, analysis of dilution in single-pass weld was analyzed. Multiple weld beads were arc welded with coated electrodes, alloyed with different chromium and carbon content on sheet metal made of structural steel S355. Welding parameters before welding each bead were the same, which means welding with the same heat input with all electrodes and thus the relevant conditions for comparison of the results. The degree of dilution of base material in weld pool was determined in three ways: by geometric method from weld cross section, geometric method with ratio of weld cross section heights and calculating on basis of comparison with EDX method of the determined chemical composition of low-dilution welds and corresponding areas of mixing. The EDX method also determined the depth of mixing zone and chemical composition of possible banding of solute-rich and solute-depleted bands. The results show that with a sufficiently large number of analyzed cross sections in a single-pass weld and with a sufficiently large number of analyzes of chemical composition on these cross sections, it is possible to accurately estimate dilution levels.

• Keywords: coated electrode, single-pass weld, dillution of base and filler material, determining dilution level, segregation