ISSN:
1662-9752
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
The present study aims to investigate the mechanism of the development of abnormalgrain sizes in the through-thickness direction of hot rolled steel strips. For this purpose, industriallyprepared steel strips were further hot rolled in a laboratory hot rolling mill, setting a variety ofrolling parameters. As found, the deformation rate in the hot rolling practice exerts an importantrole in explaining the mechanism of abnormal grain growth, especially in the close vicinity of thestrip surface. Furthermore, the influence of the cooling penetration depth, induced by the rollcontact was examined closely, as this phenomenon might support abnormal grain growthmechanisms. Additional information was found in performing a texture analysis in the throughthicknessdirection of the steel strips, in accordance with the optical metallurgical survey of themicrostructures.It will be shown that, the combination of particular hot rolling parameters provokes the occurrenceof abnormal grain growth in the through-thickness direction of the ELC steel strips. Theseparticular conditions were considered to be related to the finish hot rolling temperature and thus theroll cooling penetration depth imposed on the steel strip, the finishing reduction degree andespecially the strain rate conditions. Moreover, the observed abnormal grain growth is sensitive tothe coiling temperature applied.From the experiments, it can be concluded that the mechanism of the formation of a large grainedferrite band below the strip surface is strongly influenced by the development of a fine-grain ferritelayer at some distance below the strip surface. The existence of this layer of very small ferritegrains can be explained on the basis of texture analysis and calculations based on literature data. Inthis way, it was considered that dynamic recrystallisation of austenite at some depth below the steelstrip surface is of most significance in supporting the development of abnormally large ferritegrains. In this paper, further considerations on the mechanism of the abnormal grain growthphenomenon will be dealt with
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/15/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.539-543.4220.pdf
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