Background of branched crack formation in surface zone of continuously-cast Ti-Nb microalloyed steel slab

• Autorzy: Bekeč P. , Longauerová M. , Vojtko M. , Milkovič O. , Kadlec J. , Tréfa G. , Grimplini G.
• Języki publikacji: EN

Abstrakty

EN

Purpose: This work deals with the study of the background to the formation of branched cracks in a continuously-cast slab, at pulling rate 0.43 m.min-1. Design/methodology/approach: Samples were taken from the individual cut-outs for further analyzes. Macroscopic analysis was used to evaluate the surface quality of the analysed slabs using a Leica Wild M3Z macroscope. The microstructure was observed with an OLYMPUS VANOX-T light microscope. For the evaluation of the concentration profile of the selected elements in planes parallel to the slab surface, wavelength dispersive X-ray analysis (WDX) was used with a Camebax-MICROanalyzer. Findings: The results of the work show that branched cracks extended to a depth of 10 mm below the slab surface and occurred mostly below oscillation marks. Cracks were mostly present in the edge parts of the slab, where they were also deeper in comparison with locations in the middle of the slab width. Microstructural analysis confirmed heterogeneity of ferrite grain sizes in the slab surface skin. Wavelength-dispersive X-ray analysis of a sample with a branched crack showed chemical heterogeneity of harmful elements, mainly S and As. Research limitations/implications: Precipitation of microalloying elements in connection with the cementite can lead to higher probability of surface crack formation, as also confirmed in this study. Originality/value: of this work is background of branched crack formation in surface zone of continuously-cast Ti-Nb microalloyed steel slab.

Słowa kluczowe

EN

slab; branched cracks; oscillation marks; segregation; precipitation

PL

płyta; znaki oscylacyjne; segregacja; opad atmosferyczny

• Wydawca: International OCSCO World Press
• Czasopismo: Journal of Achievements in Materials and Manufacturing Engineering
• Rocznik: 2014
• Tom: Vol. 67, nr 2
• Strony: 58--64
• Opis fizyczny: Bibliogr. 15 poz., rys., tab.

Twórcy

autor

Bekeč P.

• ŽP Research and Development Centre, Kolkáreň 35, 976 81 Podbrezová, Slovakia
• Department of Materials Science, Technical University of Košice, Park Komenského 11, 042 00 Košice, Slovakia

autor

Longauerová M.

• Department of Materials Science, Technical University of Košice, Park Komenského 11, 042 00 Košice, Slovakia

autor

Vojtko M.

• Department of Materials Science, Technical University of Košice, Park Komenského 11, 042 00 Košice, Slovakia

autor

Milkovič O.

• Department of Materials Science, Technical University of Košice, Park Komenského 11, 042 00 Košice, Slovakia

autor

Kadlec J.

• SVÚM a.s., Institute of Research Area, Podnikatelská 565, 190 11 Praha 9 - Běchovice, Czech Republic

autor

Tréfa G.

• U.S.STEEL Košice, s.r.o., Research and Development Centre, 044 54 Košice, Slovakia

autor

Grimplini G.

• U.S.STEEL Košice, s.r.o., Research and Development Centre, 044 54 Košice, Slovakia

Bibliografia

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• [3] P. Marek, A. Ševčík, Surface Defects in Low Carbon Steel Slabs, in: M. Longauerová, G. Janák (eds.), The 1st International Conference Physical Metallurgy and Fracture of Materials ́99, Herľany, Slovak Republic, 1999, 261-264.
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• [12] P. Bekeč, M. Longauerová, Effect of cooling rate on the microstructure of slabs surface area from Ti-Nb microalloyed steel, Metalurgia Junior 2010, 26-27.05. 2010, Košice, 101-105 (in Slovak).
• [13] M. Longauerová, P. Bekeč, M. Vojtko, S. Longauer, P. Marek, Influence of cooling rate on TiNb micro-alloyed steel slab surface zone fracture morphology, Acta Metallurgica Slovaca – Conference 3 (2013) 30-39.
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