Optimisation and evaluation of different secondary metallurgy routes to achieve high-quality strip steel
This research project involving voestalpine Stahl Linz, ThyssenKrupp Steel, Corus Strip Products IJmuiden and Hüttenwerke Krupp Mannesmann has aimed at the optimisation and evaluation of different secondary metallurgy routes to achieve high-quality strip steel. Steel plants which produce high-performance steel grades with best O5 surface quality for automotive production are very interested in minimising castabilty and cleanliness problems and in optimising their secondary metallurgy route to assure low rejection rates and high yields. As is well known, location, quantity, morphology and size of inclusions have important effects on product quality. Appropriate slag metallurgy or Ca treatment results in a better castability and increased sequence length. An effective Ca modification for alumina in low carbon aluminium killed steels needs more knowledge of the reaction mechanism of Ca in steel and the behaviour of Ca after injection, including casting. The possibilities of Ca treatment in the production of high-quality steel grades are shown in this report. Methods for an optimised treatment by ladle furnace, RH degassing as well as tank degassing combinations in line with vertical bending slab casters and thin slab casters were achieved. The focus of the project was laid on the following main topics: - the basic study on formation of alumina inclusions and theory; - the basic study on shape control of inclusions in Ca treatment; - the assessment of oxide cleanness; - the optimisation of different secondary metallurgy routes. The project results in the development of a best practice to maintain competitiveness of production lines including ladle furnace and RH or tank degassing. It is certain that continuing development is needed to optimise both plant productivity and product quality.
Bibliographic Reference: EUR 23888 EN (2009), 171 pp. Euro: 20
Availability: http://bookshop.europa.eu/is-bin/INTERSHOP.enfinity/WFS/EU-Bookshop-Site/en_GB/-/EUR/ViewPublication-Start?PublicationKey=KINA23888 (Catalogue Number: KI-NA-23888-EN-S)
ISBN: ISBN: 978-92-79-11981-1
Record Number: 200910478 / Last updated on: 2009-10-12
Original language: en
Available languages: en