Karakterizacija navarenog sloja na ploči od čelika za tlačne namjene

undergraduate thesis

• Title (english): Characterization of the overlay on the plate of pressure vessel steel
• Author: Maroje Simoni
• Mentor: Vera Rede (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2025-02-24, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering

Abstract

U radu je provedena karakterizacija navarenog sloja od legure G 19 9 S Li nanešenog na
ploču od čelika P355GH. Navar je izveden postupkom elektrolučnog zavarivanja taljivom
elektrodnom žicom pod zaštitom inertnog plina argona. Analiziran je kemijski sastav ploče i
navara te makrostruktura i mikrostruktura navara. Također je izmjerena tvrdoća HV10 i HV0,2
u svim karakterističnim područjima.
U teorijskom dijelu rada opisana je implementacija čelika kao materijala u navarivanju,
karakterizacija navarenih slojeva i moguće greške pri navarivaju.
Analiza makrostrukture pokazala je da u navarenom sloju nema uočenih nepravilnosti.
Mikrostruktura materijala ploče je izrazito usmjerena, a sastoji se od ferita i perlita.
Mikrostruktura metala navara je potpuno austenitna. Linija staljivanja je pravilna i jasno
izražena. U zoni utjecaja topline došlo je do porasta kristalnih zrna ferita i perlita osobito uz
liniju staljivanja. Najviše vrijednosti tvrdoće HV10 izmjerene su na površini navarenog sloja,
a najviše vrijednosti mikrotvrdoće HV0,2 izmjerene su u zoni utjecaja topline. Analizom svih
dobivenih rezultata utvrđena je zadovoljavajuća kvaliteta navarenog sloja.

Abstract (english)

In the thesis, the characterization of the overlayed layer of the G 19 9 S Li alloy applied
to the P355GH steel plate was carried out. The overlay was made by the process of electric arc
welding with a fusible electrode wire under the protection of inert argon gas. The chemical
composition of the plate material and the overlay, as well as the macrostructure and
microstructure of the overlay, were analyzed. The hardness HV10 and HV0.2 were also
measured in all characteristic areas.
The theoretical part of the work describes the implementation of steel as a material in
welding, the characterization of the overlayed layer and possible errors during overlaying.
The analysis of the macrostructure showed that there are no observed irregularities in the
overlayed layer. The microstructure of the plate material is highly oriented, consisting of ferrite
and pearlite. The microstructure of the welded metal is completely austenitic. The melting line
is regular and clearly expressed. In the heat-affected zone, there was an increase in ferrite and
pearlite crystal grains, especially along the melting line. The highest values of the hardness
HV10 were measured on the surface of the overlayed layer, and the highest values of
microhardness HV0.2 were measured in the heat-affected zone. The analysis of all obtained
results determined the satisfactory quality of the overlayed layer.

• Keywords: karakterizacija; navar; čelik
• Keywords (english): characterization; overlay; steel
• Language: croatian
• URN:NBN: urn:nbn:hr:235:237429
• Study programme: Title: Mechanical Engineering; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka strojarstva (sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2025-02-21 12:49:27