Corrosion behavior of AH36 and S460 steel weldments in shipbuilding industry

Ζιάκας, Αλέξανδρος; Ziakas, Alexandros

dc.contributor.author	Ζιάκας, Αλέξανδρος	el
dc.contributor.author	Ziakas, Alexandros	en
dc.date.accessioned	2022-09-02T10:04:55Z
dc.date.available	2022-09-02T10:04:55Z
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/55583
dc.identifier.uri	http://dx.doi.org/10.26240/heal.ntua.23281
dc.rights	Default License
dc.subject	Corrosion	en
dc.subject	Steel	en
dc.subject	AH36	en
dc.subject	S460	en
dc.subject	Welding	en
dc.subject	Διάβρωση	el
dc.subject	Χάλυβας	el
dc.subject	ΑΗ36	en
dc.subject	Συγκόλληση	el
dc.subject	Συμπεριφορά	el
dc.title	Corrosion behavior of AH36 and S460 steel weldments in shipbuilding industry	en
heal.type	bachelorThesis
heal.classification	Corrosion	en
heal.classification	Materials Science	en
heal.classification	Welding Science	en
heal.language	en
heal.access	campus
heal.recordProvider	ntua	el
heal.publicationDate	2020-10-28
heal.abstract	The objective of the present thesis is the study of the corrosion behavior of HSLA S460 structural steel, its homogeneous weldment S460-S460 and its weldment with conventional steel AH36-S460 and the comparison with the conventional parent metal AH36 and AH36-AH36 weldment. This study investigates the corrosion performance of this steel as an alternative of conventional steel AH36 for applications on the ship. Electrochemical techniques were employed, applying DC and AC techniques, along with study of the microstructure and micro-hardness. In particular, Linear Polarization, Potentiodynamic polarization, Cyclic polarization and Electrochemical Impedance Spectroscopy electrochemical techniques were applied. The potentiodynamic polarization of the specimens proved that the phenomenon is determined by the O2 diffusion in the 3.5% NaCl solution, which is obvious in the cathodic polarization, i.e concentration polarization. Thus, it is the O2 concentration of the solution that determines the corrosion rate of the specimen. The anodic polarization is characterized by an increase of current density with increasing potential in the anodic region, indicating active corrosion behavior without passivation. The corrosion parameters show that S460 presents very similar corrosion behavior with AH36 with no significant difference. Both metals present similar microstructure, as well as their weldments. The icorr values and the consequent corrosion rates are quite similar for the parent metals and the welds. However, in EIS technique S460-S460 weld is more corrosion resistant; this difference can be explained by the difference of the perturbation applied on the specimen, with EIS. The aforementioned results prove that concerning the corrosion performance, S460 can be introduced as an alternate material instead of or along with AH36. Whereas, it is useful to study the corrosion in combination with fatigue performance.	en
heal.advisorName	Tsouvalis, Nikolaos	en
heal.committeeMemberName	Tsouvalis, Nikolaos	en
heal.committeeMemberName	Samuelides, Manolis	en
heal.committeeMemberName	Karantonis, Antonis	en
heal.academicPublisher	Εθνικό Μετσόβιο Πολυτεχνείο. Σχολή Ναυπηγών Μηχανολόγων Μηχανικών. Τομέας Ναυτικής Μηχανολογίας	el
heal.academicPublisherID	ntua
heal.numberOfPages	204 σ.	el
heal.fullTextAvailability	false