Effect of mould flux on scale adhesion to reheated stainless steel slabs

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dc.contributor.advisor Pistorius, Petrus Christiaan en
dc.contributor.postgraduate Ndiabintu, Mukadi Jean-Jacques en
dc.date.accessioned 2013-09-07T16:53:44Z
dc.date.available 2009-12-09 en
dc.date.available 2013-09-07T16:53:44Z
dc.date.created 2009-09-02 en
dc.date.issued 2009-12-09 en
dc.date.submitted 2009-11-26 en
dc.description Dissertation (MSc)--University of Pretoria, 2009. en
dc.description.abstract Effects of mould flux contaminant on scale-steel adhesion and hydraulic descaling of scale formed on slabs were investigated. In this investigation, stainless steel type 304 (austenitic with 18% Cr and 8% Ni) and specific mould fluxes were used when growing the scale on contaminated samples under simulated industrial reheating conditions, with subsequent high pressure water hydraulic descaling. The basic hypothesis was that the steel-scale adhesion depends on the microstructure of different phases present in the scale, the segregation of specific elements at the interface and the interfacial morphology of the scale after reheating. It was found that mould flux contaminant decreases scale-steel adhesion and therefore improved the descaling effectiveness significantly compared to non contaminated stainless steel. The descaling effectiveness of contaminated and uncontaminated slab was dependent to the presence of metal free paths (chromite layers along the austenite grains boundaries) and the presence of unoxidized metal in the scale due to nickel enrichment at the interface. Compared to the uncontaminated samples, the descaling of contaminated samples was efficient which could be due to the fact that some mechanisms which increase scale– steel adhesion (notably nickel enrichment at the interface) were considerably reduced. For all contaminated samples, the descaling effectiveness after visual observation were close to 100% and it was found that mould flux type 832 ( low basicity) gave a high descaling efficiency with better steel surface quality after descaling compared to mould fluxes type 810 and RF1. en
dc.description.availability unrestricted en
dc.description.department Materials Science and Metallurgical Engineering en
dc.identifier.citation Ndiabintu, Mukadi, J-J 2008, Effect of mould flux on scale adhesion to reheated stainless steel slabs, MSc dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://hdl.handle.net/2263/29840 > en
dc.identifier.other E1466/ag en
dc.identifier.upetdurl http://upetd.up.ac.za/thesis/available/etd-11262009-192807/ en
dc.identifier.uri http://hdl.handle.net/2263/29840
dc.language.iso en
dc.publisher University of Pretoria en_ZA
dc.rights © 2008, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. en
dc.subject Scale en
dc.subject Chromite en
dc.subject Tendrils of nickel-rich filigree en
dc.subject Austenite grain boundaries en
dc.subject Interfacial morphology en
dc.subject Free oxygen en
dc.subject Stainless steel en
dc.subject Mould flux en
dc.subject Reheating en
dc.subject Hydraulic descaling en
dc.subject Internal oxidation en
dc.subject UCTD en_US
dc.title Effect of mould flux on scale adhesion to reheated stainless steel slabs en
dc.type Dissertation en


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