Materials Research and Engineering Edited by B. Ilschner and N.J. Grant

Materials Research and Engineering Edited by B. Ilschner and N.J. Grant

Julian Szekely Goran Carlsson Lars Helle Ladle Metallurgy With 137 Figures and 24 Tables Springer-Verlag New York Berlin Heidelberg London Paris Tokyo

Prof. JULIAN SZEKELY Department of Materials Science and Engineering Massachusetts Institute of Technology Cambridge, MA 02139/USA GQRAN CARLSSON MEFOS, The Metallurgical Research Plant P.O. Box 812 S 951 28 Lulea, Sweden LARS HELLE OVAKO STEEL Oy Ab SF 55100 Imatra, Finland Series Editors Prof. BERNHARD ILSCHNER Laboratoire de Metallurgie Mecanique Departement des Materiaux, Ecole Poly technique Federale CH -1007 Lausanne/Switzerland Prof. NICHOLAS J. GRANT Department of Materials Science and Engineering Massachusetts Institute of Technology Cambridge, MA 02139/USA Library of Congress Cataloging-in-Publication Data Szekely, Julian, 1934- Ladle metallurgy/julian Szekely, G6ran Carlsson, Lars Helle. p. cm.-(materials research and engineering) Bibliography: p. ISBN-13: 978-1-4612-8147-4 e-isbn-13: 978-1-4612-3538-5 DOl: 10.1007/978-1-4612-3538-5 I. Inoculation (Founding) 2. Steel founding. I. Carlsson, G6ran. II. Helle, Lars. III. Title IV. Series. TS233.s981988 671.2-dc19 88-20017 Printed on acid-free paper. All rights reserved. This work may not be translated or copied in whole or in part without the written permission of the publisher (Springer-Verlag, 175 Fifth Avenue, New York, NY 10010, USA), except for brief excerpts in connection with reviews or scholarly analysis. Use in connection with any form of information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed is forbidden. The use of general descriptive names, trade names, trademarks, etc. in this publication, even if the former are not especially identified, is not to be taken as a sign that such names, as understood by the Trade Marks and Merchandise Marks Act, may accordingly be used freely by anyone. Springer-Verlag New York Inc. 1989 Softcover reprint of the hardcover I st edition 1989 Typesetting by Asco Trade Typesetting Ltd., Hong Kong.

Editors' Preface This book seeks to provide a comprehensive coverage of the important and growing field of ladle metallurgy, including theory, practice, and economics. During the past decade, major advances have been made in the secondary metallurgy of steel and other metals; indeed, secondary metallurgy, that is, the ladle treatment of molten metals, following the melting and refining steps, has become an important and inevitable part of the overall processing sequence. Ladle metallurgy is attractive because it can provide an effective means for adjusting and fine-tuning the composition and temperature of the molten products prior to solidification processing. Ladle metallurgy allows us to produce materials of very high purity and will become increasingly an essential process requirement. Indeed, many of the novel casting techniques will mandate steels of much higher cleanliness than those in current practice. Of course, ladle metallurgy or secondary metallurgy is not limited to steel; indeed, major advances have been made and are being made in the secondary processing of aluminum, aluminum alloys, and many specialty metals. This book provides, for the first time, a comprehensive treatment of the subject, which includes both the science base and the many practical, real-world considerations that are necessary for the effective design and operation of ladle metallurgy systems. The aim of the theoretical chapter is to provide insight and to develop the fundamental basis of ladle metallurgy systems. The chapter concerning practice reflects the many years of practical experience with the operation ofladle metallurgy systems. Finally, the chapter on economics provides a discussion on both the capital costs and the operating costs of secondary metallurgy systems. This book should be helpful to students of materials processing and to practicing metallurgists, in both the steel and the specialty metals fields. Cambridge, MA, USA, July 1988 Lausanne, Switzerland, July 1988 N.J. Grant B. Ilschner

Contents 1 Overview of Injection Technology G6ran Carlsson.... 1.1 Introduction... 1 1.2 Apparatus... 1 1.3 Hot Metal Pretreatment... 4 1.4 Steel Refining... 8 1.5 Foundry... 23 1.6 Copper... 23 1.7 Aluminium... 24 1.8 Ferro Alloy... 24 References....................................................... 25 2 The Fundamental Aspects of Injection Metallurgy Julian Szekely... 27 2.1 Introduction... 27 2.2 Thermodynamics... 27 2.3 Gas and Solids Delivery... 40 2.4 Injection of Particles into Melts... 50 2.5 The Kinetics of Ladle Metallurgy Operations... 54 2.6 Fluid Flow and Mixing in Ladle Metallurgy Systems... 56 2.7 Convective Mass Transfer and Kinetics... 64 2.8 Heat Transfer... 68 References....................... 71 3 Injection Practice in the Secondary Metallurgy of Steel Lars Helle... 73 3.1 Introduction... 73 3.2 Description of the Process..................................... 73 3.3 Theoretical Approach to Powder Injection... 101 3.4 Discussion of the Results Obtained with Powder Injection.......... 110 3.5 Costs and Productivity... 145 3.6 Future Aspects... 145 References....................................................... 147 4 Economic Considerations G6ran Carlsson... 151

viii Contents 4.1 Introduction... 151 4.2 Unit Price... 151 4.3 Consumption... 151 4.4 Capital Costs................................................ 151 4.5 Economic Interactions with Other Processes... 152 5 Testing Technique for Powder Injection Goran Carlsson... 154 5.1 Dry Blowing Tests... 154 5.2 Screen Analysis... 155 5.3 Hand Test of Powder Material... 157 5.4 Water Model Tests........................................... 157 5.5 Angle of Repose... 162 References....................................................... 163 Subject Index..................................................... 165