Casting and solidification of steel. Pig iron and direct reduction Part I Summary research report Final report

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steel research reports
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Casting and solidification of steel
Part I
Summary research report
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1978 EUR 5861 ΕΓ COMMISSION OF THE EUROPEAN COMMUNITIES
steel research reports
Pig iron and direct reduction
Casting and solidification of steel
Part I
Summary research report
HATTO JACOB I
Institut für Eisenforschung, GmbH, Düsseldorf
Convention No 6210-50
FINAL REPORT
Published by the Directorate-General
Scientific and Technical Information and Information Management
1978 EUR 5861 EN LEGAL NOTICE
Neither the Commission of the European Communities nor any person acting
on behalf of then is responsible for the use which might be made of
the following information Summary Research Report on the Results
of the Co-operative Programme
on the Casting and Solidification of Steel I
(Contract No. 6210-50)
by
Hatto Jacobi
Max-Planck-Institut fuer Eisenforschung GmbH, Dusseldorf 2.
Introduction
In 196';), co-operative work by European iron and steelworks
and research institutes on the "casting and solidification
of steel" was commenced on the initiative and with the financ­
ial support of the European Coal and Steel Community (ECSC).
The processes taking place during the casting and solidification
of steel are of great significance for the economics of steel
production processes and the properties of the steels in use.
There was little foundation for the state of basic knowledge
of the sometimes very involved physical and chemical processes
in the solidification of steel during the period before the
commencement of this research programme. In steelworks, control
of the casting and solidification process was generally effected
by methods developed empirically,, In recent years increased
attempts have been observed on a worldwide scale to improve
the technology in this area by systematic investigations so
as to alter this unsatisfactory state of affairs. Within the
European Community, it appeared sensible and desirable to co­
ordinate the current and planned investigations in the iron and
steelworks with the object of closing, as far as possible, the
gaps in our knowledge and to make optimum use of the means
employed by avoiding duplication.
The following iron and steelworks and research institutes took
part in the "casting and solidification of steel I" research
programme:
Centre de Recherches Métallurgiques (CRM), Luettich
Centro Sperimentale Metallurgico s.p.a. (CSM), Rom
Cockerill-S.A. Cocke riLL-Ougree-Providence et Esperaace-
Longdoz, Luettich
Creusot-Loire, Le Creusot
Hoesch Huettenwerke AG, Dortmund
Institut de .Recherches de la Siderurgie Française (IRSID), 3.
Maizieres-les-Metz
Max-Planck-Institut fuer Eisenforschung GmbH, Dusseldorf
Thyssen Henrichshutte AG, Hattingen
Thyssen Niederrhein AG, Oberhausen.
On completion of this first research programme there was some
type of break. Consequently, the results and experiences
collected in 55 individual reports have been evaluated and
reproduced in concentrated form in the present research report.
Almost all important technical and scientific problems in the
crystallisation of steel are discussed under the following
general headings: deoxidation of the liquid steel; heat
transport and solidification structure in ingot casting and
continuous casting; formation of inclusions, pinholes and
micro-shrinkage, macro-segregation of large anvil blocks;
solidification of electro slag remelt blocks as well as
methods for quantitative structure analysis. The application
of the results in practice was also in the forefront of each
piece of work, which primarily strove for a basic theoretical
penetration of the material or, because of the complicated
nature of the industrial process, were based on model experiments
on similar systems.
This Cirst review makes it clear that a closed theory of
solidification, expressed through a universal "solidification
model" embracing all aspects of solidifcation could not have
been found to date. The investigations were therefore con­
tinued in a second research programme in progress since 1975·
A. third programme with the emphasis on the basis of continuous
casting of steel will, be started shortly.
The Commission of the European Community hopes, with this
first review of the research results obtained, to lead to a
widening of the knowledge on steel manufacture and in this
way to have been successful in furthering technical advantages. k.
Contents
Paare
1. Deoxidation
— - - 1
1.1 Deoxidation equilibria in liquid irons
1.1.1 Evaluation of the literature
1.1.2 The Fe-Mn-0 equilibrium
1.1.3 The Fe-Al-0m
1.2 Introduction of solid electrolytes for
the measurement of the progress of
deoxidation
1.3 The precipitation deoxidation procedure
I.3.I Deoxidation with Al, Ce, La, Ti and
Zr
1·3·2 Combined deoxidation with Mn and Si
1·3·3dn with Si and
alkaline earths
1.3·**· The separation of the deoxidation
products
1.3-*+-1 Influence of surface
tension on the separation
mechanism for solid oxide
inclusions
1.3.4.2 Growth shapes of the
inclusions
2. Heat Conductivity Problems in Solidification
2.1 Heat conductivity models for
solidification
2.1.1 Use of the difference process
2.1.2 Use of heat balance integral
2.1.3 Use of Green's function
2.1.4 Assessment of heat conductivity
of molten steels 5.
Page
2.2 Continuous casting
2.2.1 Reduction of overheating
2.2.2 Heat transfer from ingot to ingot
mould· and solidification law
2.2.3 Air -gap. formation
2.2.4 Effect of shape of ingot mould
2.3 Continuous casting
2·3·1 Ingot moulds
2·3·1·1 Heat transfer from billet
to ingot mould
2·3·1·2 Effect of casting radiation
on flow and temperature
distribution
2·3·1·3 Effect of casting powders
in continuous castings
2.3·2 Heat transfer in the secondary
cooling zone
2·3·3 Casting capacity and solidification
law
Solidification Structure in Ingot and
Continuous Casting
5.1 Basis of dendritic solidification
3.1.1 Dendrite morphology
3.1.2 Interdcndritic enrichment
3.1.3 Formation of sulphide inclusions
3.1-4 Peritectic reaction on
solidification
5-1.5 Influence on primary structure
5-1.5-1 Grain refining of the
primary structure of
ingot casting
5-1·5·2 Grain refining by electro
magnetic stirring 6.
Paee
5-2 Solidification of rimmed steel
3.2.1 Gas bubble formation and flow
3.2.2 Segregation with rimmed steel
5-2.2.1 Enrichment in front of
solidification front
5.2.2.2 Horizontal and vertical
macrosegregation of
rimmed ingots
5.2-5 Thermal and mechanical post
treatment of rimmed ingots
4. Solidification of Large Forging-Grade Ingots
4.1 Arrangements for calculating
gravitational segregation
4.2 Solidification structure of large
forging-grade ingots
4.5 Segregation in large forging grade ingots
4.5.1 Macrosegregation
4.5·2 Microsegregation
4.4 Inclusions in large forging grade ingots
4.4.1 Distribution of inclusions and degree
of purity
4.4.2 Variation in the content of
exogenous inclusions
4.5 Hardening of electro-slag remelt ingots
4.6 Influence of segregation on the technological
properties of large conventionally cast
forging grade ingots and of electro-slag
remelt ingots
5. Evaluating the Solidification Texture with
the Aid of Quantitative Metallography