Detection and analysis of non-conformities in S355JR non-alloy structural steel

Scientific paper - Original scientific paper

• Author: Franjo Kozina
• Author: Zdenka Zovko Brodarac
• Author: Luka Voloder
• Author: Ivan Grgić
• Editor: Nikša Čatipović
• Editor: Jure Krolo
• Editor: Nikola Gjeldum
• Author's institution: University of Zagreb; Faculty of Metallurgy; (Department of Process Metallurgy); (Laboratory of Iron, Steel and Founding)
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Metallurgy; Process Metallurgy

Abstract (english)

Although construction materials are considered the most predictable components of a construction project, design and material challenges represent a major cause of productivity loss. The occurrence of non-conformities is a consequence of the very difficult quality assurance under industrial conditions, especially in the context of material processing. In this paper, non-conformities detected during the ultrasonic testing of the steel infrastructure were analysed. The investigation of non-conformity area included the chemical composition analysis, the thermodynamic calculations of the solidification sequence and metallographic analysis. The ultrasonic test results indicated the crocodile effect associated with the thermomechanical processing of steel ingots containing casting defects. This fact was supported by the results of the non-equilibrium solidification sequence. Microstructural analysis of the non-conformity area indicated the presence of non-metallic inclusions and cracks. The crack nucleation and propagation occurred during the thermo-mechanical processing. The microstructure constituents also indicated improperly performed thermo-mechanical processing. The rolling texture and acicular ferrite pointed to improperly performed normalization. The conducted research indicates the need to impose additional requirements on the microstructure of the final product, although it is not required by the EN 10025-2:2019 standard.

• Keywords (english): S355JR structural steel; Thermo-mechanical processing; Ultrasonic testing; Microstructure; Non-metallic inclusions
• Language: english
• Publication type: Scientific paper - Original scientific paper
• Publication status: Published
• Peer review: Peer review - international
• Publication version: Published version
• Publication title: Proceedings of 13th International Conference Mechanical Technologies and Structural Materials 2024
• Edition: prvo izdanje
• Numbering: pp. 205-217
• p-ISSN: 1847-7917
• URN:NBN: urn:nbn:hr:115:696477
• Publication: 2024-10-19
• Conference: Title: 13th International Conference Mechanical Technologies and Structural Materials 2024; Acronym: MTSM 2024; Location: Split, Croatia; Organizer: Fakultet elektrotehnike, strojarstva i brodogradnje Sveučilišta u Splitu; Start date: 2024-10-19; End date: 2024-10-20; Assembly type: Lecture
• Type of resource: Text
• Publisher: HRVATSKO DRUŠTVO ZA STROJARSKE TEHNOLOGIJE
• Publishing place: Split
• Access conditions: Open access
• Created on: 2024-10-16 06:50:50