Slab Ingot Mould Design CDNA09087ENC_001

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Commission of the European Communit ies

techn ica l s tee l research

S t e e l m a k i n g

E s t a b l i s h m e n t o f d e s i g n p a r a m e t e r sf o r l a r g e s l a b t y p e i n g o t m o u l d s

R e p o r tEUR 9 0 8 7 EN

Blow-up from microfiche or iginal


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Commission of the European Communi t ies

t e c h n i c a l s t e e l r e s e a r c h

Stee lmak ing

E s t a b l i s h m e n t o f d e s i g n p a r a m e t e r sf o r l a r g e s l a b t y p e i n g o t m o u l d s

C D HARLE, M. J. LEADBETTERBRITISH STEEL CORPORATION9, A lber t Em bankmentGB-LONDON SE1 7SN

Contract No 7210-CA/813(01.04.1981 - 31.03.19 83)FINAL REPORT

Directorate-GeneralSc ience, Research and Development1984 EUR 9 0 8 7 EN


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P u bl i s h e . d b y t h eC O M M I S S I O N O F T H E EU R O PE A N C O M M U N I T I E SD i r e c t o r a t e - G e n e r a lI n f o r m a t i o n M a r k e t a n d I n n o v a t i o n

B t im e n t J e a n M o n n e tL U X E M B O U R G

LEGAL NOTICENei ther the Commission of the European Communi t ies nor any person act ingon behal f of the Commission is responsib le for the use which might be made ofthe fo l l ow in g in fo rmat ion

) ECSC-EEC-Euratom, Brus sels Luxem bourg


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ESTABLISHMENT OF DESIGN PARAMETERS FOR LARGESLAB TYPE INGOT MOULDS

F I N A L R E P O R T

Agreement No. 7210.CA/813

C D . HarleM.J. LeadbetterBritish Steel CorporationWelsh Laboratory

EUR 9087 EN


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ESTABLISHMENT OF DESIGN PARAMETERS FOR LARGE SLAB TYPE INGOT MOULDSBritish Steel CorporationECSC Agreement No. 7210.CA/813Summary: Final Technical Report

An investigation has been carried out into the development of a finite elementthermal stress analysis technique for use as a design procedure for large slabtype ingot moulds.As part of this study physical and mechanical properties of mould iron have beendetermined in the laboratory up to elevated temperatures for model calibration. Aseries of plant trials were carried out with four selected mould types in whichtemperature distributions within the mould wall thickness and surface strainlevels were measured from the start of teeming to stripping of the ingot fromthe moulds. The finite element thermal stress analysis procedure requires apreliminary transient thermal finite element analysis to determine how the mouldtemperature distributions change with time after steel has been teemedinto the cold ingot mould, followed by a finite element thermal stress analysis.A good agreement was obtained between plant measured and model predictedtemperatures.A recommended design procedure has been formulated based on comparing stresslevels generated by the model with those of a 'bench-mark' mould of known goodplant performance. The essential stages of this routine include (i) preliminary,low cost, two dimensional horizontal thermal stress analysis which can give usefuldesign guidelines,(ii) the derivation of a low cost quasi-three dimensional stressanalysis routine (obtained by combining horizontal and vertical 2-D stressanalyses) and comparison with the 'bench-mark' study. Three dimensional thermalstress analysis, which is very expensive, is recommended in cases where a moulddesign contains non-symmetrical features, for example a skirt only applied toopposite faces of the mould at the base.


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CONTENTS Page No.1. INTRODUCTION 12. DETERMINATION OF MATERIAL PROPERTIES FOR INGOT MOULD CAST IRON 2

2.1. Introduction 22.2. Preparation of Test Blocks/Samples 22.3. Material Property Determinations by British Cast IronResearch Association (B.C.I.R.A.) 32.3.1. Notes on Test Procedure 32.3.2. Discussions on Properties of Test Blocks 4

3. DETERMINATION OF MOULD DIMENSIONS 53.1.Conventional Measuring Techniques 53.2.Measurement of Internal Profile of Ingot Moulds usingSpecially Constructed Mould Profilometer Equipment 5

4. INSTRUMENTATION OF INGOT MOULDS FOR PLANT TRIALS 64.1. Requirements for Mould Instrumentation 64.2. Mould Types Chosen for Trial 64.3. Temperature Measuring Equipment 64.4. Strain Measuring Equipment 64.5. Mould Instrumentation Details 74.6. Arrangements of Trial Moulds during Casting 8

5. RESULTS OF INSTRUMENTED MOULD TRIALS 85.1. 492 Bottle-Top Mould (Average mould life in service 120 heats) 8

5.1.1. Mould Temperature Measurements 85.1.2. Strain Gauge Results 95.1.3. Mould Dimensional Checks 9

5.2. Ti Open Top Mould (Average Mould Life in Service 84 Heats) 105.2.1'. Mould Temperature Measurements 105.2.2. Strain Gauge Measurements 105.2.3. Mould Dimensional Checks 10

5.3. Us Bottle Top Mould (Average Mould Life in Service 96 Heats) 115.3.1. Mould Temperature Measurements 115.3.2. Strain Gauge Measurements 115.3.3. Mould Dimensional Checks 11

5.4. V3/48I Open Top Mould (Average Mould Life in Service 103 Heats) 125.4.1. Mould Temperature Measurements 125.4.2. Strain Gauge Measurements 125.4.3. Mould Dimensional Checks 125.5. Comments on Measured Strain Values and Mould Failure Patterns 125.5.1. Measured Strains 125.5.2. Mould Failure Patterns 13


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6. FINITE ELEMENT STUDIES (Sub-Contracted work by Design Audit Limited) 146.1. Outline of Finite Element Studies 146.2. Mould Selection 146.3 Derivation of Temperature Distribution in the Mould 146.4. Derivation of Thermal Stress Analysis 156.5. 492 Mould - 3 Dimensional Model Studies 156.6. Ti Mould Thermal Stress Analysis Studies 16

6.6.1. Ti Mould Mid-Height Horizontal Section 166.6.2. Modified Ti Mould 166.6.3. Ti Mould Plasticity Effects 166.7. Recommended Design Procedure 17

7. INFLUENCE OF PHYSICAL PROPERTY DATA ON THERMAL STRESS LEVELSOF THE 492 MOULD 177.1. 492 Mould 2-D Analysis using Spheroidal Graphite Properties 18

7.1.1. Derivation of Temperature Distribution in the Mould 187.1.2. Thermal Stress Analysis 187.1.3. Modified 492 Mould 18

7.2. 492 Mould 2-D Analysis - Compacted Graphite Properties 198. CONCLUSIONS 19

REFERENCES 20TABLES 21FIGURES 49APPENDICES 117


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List of TablesPage No.

1. Comparison of Structure of Trial Moulds and Test Blocks 212. Variation of Modulus of Elasticity and Thermal Conductivityfor Spheroidal and Compacted Graphite Irons 223. Details of Mould Types used for Plant Trials 234. Depths of Holes for Insertion of Thermocouples 245. Fixing Mode for Strain Gauges(Common to all Four Trial Moulds) 256. Summary of Trials - Mould Type:492 267. Summary of Strain Gauge Results - 492 MouldStrain and Stress Values (Maximum) 278. Summary of Strain Gauge Results - 492 MouldStrain and Stress Values (0.2 Hours) 289. Summary of Trials - Mould Type: Ti 2910. Summary of Strain Gauge Results - Ti MouldStrain and Stress Values (Maximum) 3011. Summary of Strain Gauge Results - Ti Mould(Strain and Stress Values (0.2 Hours) 3112. Summary of Trials Mould Type - U5 3213. Summary of Strain Gauge Results U5 Mould(Strain and Stress Values (Maximum) 3314. Summary of Strain Gauge Results - U5 Mould(Strain and Stress Values (0.2 Hours) 3415. Summary of Trials - Mould Type: V3/481 3516. Summary of Strain Gauge Results - V3/48I MouldStrain and Stress Values (Maximum) 3617. Summary of Strain Gauge Results - V3/48I MouldStrain and Stress Values (0.2 Hours) 3718. Summary of Strain Gauge Results - Maximum Strain Values 3819 Pnysical Properties Used by Design Audit Limited forFinite Element Thermal Stress Analysis on the 492(Bottle-top) and Ti (Open-top) Moulds 3920. Summary of Spheroidal Graphite Cast -Iron Physical Properties 4021. 492 Mould Horizontal Model, Stress Distributionat Nodes Mid-Height 4122. 492 Mould Horizontal Model Stress Distribution atNodes Mid-Height 4223. Summary of Physical Properties - Compacted Graphite Case 4324. 492 Mould Horizontal Model, Stress Distribution -Mid-height 44Calculation Sheets 1 - 4 45

Appendix TablesA2.1 492 Mould Horizontal Model, Stress Distribution at Nodes(Mid-Height) 152A2.2 Stress Concentration at the Corner of the 492 Type Mould(Mid-Height) 153A2.3 Heat Transfer Data for the Axisymmetric Analysis 154A2.4 Tl Mould, 2-D Horizontal Model, Mid-Height,Stress Distribution at Nodes 155A2.5 Stress Concentration at theCorner of the Tl Type Mould(Mid-Height) 156

Calculation Sheets A2.1 - A2.15 157


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List of FiguresPage No.

1. Position where Sample Blocks were cut from the Broad NarrowWalls of a 561 Type Ingot Mould 492. General View of Equipment for Measuring Profile ofIngot Mould Faces 503. View of Measuring Head Arrangement of Mould ProfileMeasuring Equipment 514. Relationship between Apparent Strain and Temperature 525. Relationship between % Change in Gauge Factor and Temperature 536. Bottle-Top Mould for Instrumentation with Thermocouplesand Strain-Gauges 547. Open-Top Mould for Instrumentation with Thermocouplesand Strain Gauges 558. General View of Instrumented Mould and Insulated Housingfor Instruments 569. Mould Type 492(2) Bottle-Top (Thermocouple Channels8 to 11) Location - Base of Narrow Wall 5710. Mould Type 492(2) Bottle-Top (Thermocouple Channels12 to 15) Location - Mid Height of Narrow Wall 5811. Mould Type 492 (2) Bottle-Top (Thermocouple Channels16 to 18) Location - Base of Corner 59 5912.Mould Type 492 (2) Bottle-Top (Thermocouple Channels19 to 21) Location - Mid height of Corner 6013.Mould Type 492 (2) Bottle-Top (Thermocouple Channels22 to 25) Location - Base of Broad Wall 6114.Mould Type 492 (2) Bottle-Top (Thermocouple Channels26 to 29) Location - Mid-Height of Broad Wall 6215.Mould Type 492 (2) Bottle-Top (Thermocouple Channels12 to 15) Location - Mid-Height of Narrow Wall 6316.Mould Type 492 (2) Bottle-Top (Thermocouple Channels26 to 29) Location - Mid Height of Broad Wall 64

17.Comparison of Methods for Surface Temperature Measurements 6513.Mould Type 492. Bottle-Top (Strain Gauge Channel 1 -Horizontal) Location - Mid-Height of Narrow Viali 6619.Mould Type 492 Bottle-Top (Strain Gauge Channel 4 -Horizontal) Location - Mid-Height of Corner 6720.Mould Type 492 Bottle-Top (Strain Gauge Channel 6 -Horizontal) Location - Mid-Height of Broad Wall 6821.Deviation from Standard Dimensions - Mould Inner Walls:1. North Narrow Wall - 4922.South Narrow Wall - 492 6922.Deviation from Standard Dimensions - Mould Inner Walls:1. West Broad Wall - 4922. East Broad Wall - 492 7023.Mould Type (01) Open-Top (Thermocouple Channels8 to 11) Location - Base of Narrow Wall 7124.Mould Type (01) Open-Top (Themo


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33. Mould Type Tl. Open-Top (Strain Gauge Channel 6 -Horizontal) Location - Mid Height of Broad Wall 8134.Deviation from Standard Dimensions - Mould Inner Walls:1. North Narrow Wall - Ti2. South Narrow Wall - Ti 8235.Deviation from Standard Dimensions - Mould Inner Walls:1. West Broad Wall - TiEast Broad Wall - Ti 8336.Mould Type (U5) Bottle. Top (Thermocouple Channels 848 to 11) Location - Base of Narrow Wall37.Mould Type (U5) Bottle. Top (Thermocouple Channels12 to 15) Location - Mid Height of Narrow Wall 8538.Mould Type (U5) Bottle. Top (Thermocouple Channels16 to 18) Location - Base of Corner 8639.Mould Type (U5) Bottle. Top (Thermocouple Channels19 to 21) Location - Mid Height of Corner 8740.Mould Type (U5) Bottle. Top (Thermocouple Channels22 to 25) Location - Base of Broad Wall 8841.Mould Type (U5) Bottle. Top (Thermocouple Channels26 to 29) Location - Mid Height of Broad Wall 8942.Mould Type (U5) Bottle. Top (Thermcouple Channels12 to 15) Location - Mid Height of Narrow Wall 9043.Mould Type (U5) Bottle. Top (Thermocouple Channels26 to 29) Location - Mid Height of Broad Wall 9144.Mould Type U5 Bottle-Top (Strain Gauge Channel 1 -Horizontal) Location - Mid Height of Narrow Wall 9245.Mould Type U5 Bottle-Top (Strain Gauge Channel 4 -Horizontal) Location - Mid Height of Corner 9346.Mould Type U5 Bottle. Top (Strain Gauge Channel 6 -Horizontal) Location - Mid Height of Broad Wall 9447.Deviation from Standard Dimensions - Mould Inner Walls:-1. North Narrow Wall - Us2. South Narrow Wall - U 5 9548.Deviation from Standard Dimensions - Mould Inner Walls:-1. West Broad Wall - Us2. East Broad Wall - Us 9649.Mould Type 481 (V3) Open-Top (Thermocouple Channels8 to 11) Location - Base of Narrow Viali 9750.Mould Type 481 (V3) Open-Top (Thermocouple Channels12 to 15) Location - Mid Height of Narrow Wall 9851.Mould Type 481 (V3) Open-Top (Thermocouple Channels16 to 18) Location - Base of Corner 9952.Mould Type 481 (V3) Open-Top (Thermocouple Channels19 to 21) Location - Mid Height of Corner 10053.Mould Type 481 (V3) Open-Top (Thermocouple Channels22 to 25) Location - Base of Broad Wall 10154.Mould Type 481 (V3) Open-Top (Thermocouple Channels26 to 29) Location - Mid Height of Broad Wall 10255.Mould Type V3 Open-Top (Strain Gauge Channel 1 -Horizontal) Location - Mid Height of Narrow Wall 10356.Mould Type V3 Open-Top (Strain Gauge Channel 4 -Horizontal) Location - Mid Height of Corner 10457.Mould Type V3 Open-Top (Strain Gauge Channel 6 -Horizontal) Location - Mid Height of Broad Wall 10558.Deviation from Standard Dimensions - Mould Inner Walls:-1. North Narrow Wall - 481 (V)2. South Narrow Wall - 481 (V) 10659.Deviation from Standard Dimensions - Mould Inner Walls:-1. West Broad Wall - 481 (V)2. East Broad Wall - 481 (V) 10760.Comparison of Predicted and Measured Strain Values(492 Mould, Mid-Height Narrow Wall) 10861.Mean Life Versus Maximum Measured Strain at Mid-Heighton Broadwall Ingot Mould Types 492, V4, U5 and Tl 10962. Comparison of Predicted and Measured Strain Values(Tl Mould, Mid-Height Narrow Wall) 110

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63.Geometry of Mid-Height Horizontal Section forType 492 Mould 11164. 2D Mesh for Type 492 Mould 11265.Computer Predicted Temperature Profile for 492 Mouldafter 720 Seconds 11366.492 Mould, Mid-Height Broadwall - Validation Results 11467.Comparison of Predicted and Measured Strain Values(492 Mould, Mid-Height Narrow Wall) (Revised Mould IronThermal Properties for Spheroidal Graphite Iron) 11568.Comparison of Predicted and Measured Strain Values(492 Mould, Mid-Height Narrow Wall) 116

Appendices FiguresAl.l Specimen Preparation from Sample Taken from the Ingot

Mould Iron 121Al.2 Stress/Strain Relationship - Broadwall Sample 122Al.3 Expansion and Contraction Progress - 20C - 900C -20C - Broadwall Sample 123Al.4 Microstructure from Broadwall Sample (x 20 Etched4%Picral) 124Al.5 Stress/Strain Relationship - Narrow Wall Sample 125Al.6 Expansion and Contraction Progress - 20C - 900C -20C - Narrow Wall Sample 126Al.7 Microstructure from Narrow Wall Sample (x 20 Etched4%Picral) 127

A2.1 Dimensions of the 492 Bottle Top Mould 172A2.2 Dimensions of the 481 (V3) Open Top Mould 173A2.3 Dimensions of the U5 Bottle Top Mould 174A2.4 Dimensions of the Tl Open Top Mould 175A2.5 Mould Type 492(2) Bottle-Top (Thermocouple Channels8 to 11) Location - Base of Narrow Wall 176A2.6 Mould Type 492 (2) Bottle-Top (Thermocouple Channels12 to 15) Location - Mid Height of Narrow Wall 177A2.7 Mould Type 492 (2) Bottle-Top (Thermocouple Channels22 to 25) Location - Base of Broad Wall 178A2.8 Mould Type 492(2) Bottle-Top (Thermocouple Channels-26 to 29) Location - Mid Height of Broad Wall 179A2.9 Thermal Gradients 180A2.10 Design Procedure 181A2.11 Schematic Diagram of a Section Through the Mould 182A2.12 Thermal Conductivity of Air at Atmospheric Pressure 183A2.13 Convective Heat Loss Coefficient as a Function ofWall Temperature 184A2.14 Radiative Heat Loss Coefficient as a Function of MouldWall Temperature 185A2.15 Broadside Mid-Height Temperature Profiles for 0 to In -492 Mould 186A2.16 Broadside Mid-Height Temperature Profiles for 1 to lOh 187A2.17 Mean Mould Temperature as a Function of Time -Broadside Mid-Height i88A2.18 Mean Mould Temperature as a Function of Time -Broadside - Mid-Height 189A2.19 Specific Heat Capacity for Spheroidal Graphite and Flake-Graphite Cast Iron 190A2.20 492 Mould Broadside Mid-Height - Validation Results 191A2.21 Dimensions of the Type 492 Mould 192A2.22 Geometry of Mid-Height Horizontal Section for 492 Mould 193A2.23 2-D Mesh for the Type 492 Mould 194A2.24 Computer Predicted Temperature Profile after 30 Minutes -492 Mould 195

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A2.25 The Variation of 0.2% Proof Stress with Temperature 196A2.26 Dimensions of the Mould and Base Plate used in theAxisymmetric Analysis - 492 Mould 197A2.27 Mesh for the Axisymmetric Analysis - 492 Mould 198A2.28 Temperature Distribution for 492 Mould AxisymmetricAnalysis,Mid-Height 199A2.29 Comparison of Horizontal Stresses - 492 Mould at180 Seconds 200A2.30 Comparison of Horizontal Stresses - 492 Mould at720 Seconds 201A2.31 Comparison of Horizontal Stresses - 492 Mould at3600 Seconds 202A2.32 Largest Absolute Principal Stress after 720 Seconds- 492 Mould 203A2.33 Geometry of the Tl Mould at Mid-Height 204A2.34 Finite Element Mesh for the Tl Mould, Mid-Height 205A2.35 Maximum Absolute Principal Stress after 720 Seconds -Tl Mould Mid-Height 206A2.36 3-D Mesh of the 492 Mould and Base Plate 207A2.37 Temperature Profiles for the Broadside Mid-Height forthe Type 492 Mould 208A2.38 Temperature Profiles for the Narrow Side Mid-Heightfor the Type 492 Mould 209A2.39 Temperature Profiles for the Broadside Mid-Pointafter 720 Seconds, 492 Mould 210A2.40 Temperature Profile through the Narrow Side Mid-Pointafter 720 Seconds, 492 Mould 211A2.41 Von Mises Stress - 492 Type Mould, Narrow SideMid-Height, Time = 720 Seconds 212A2.42 Von Mises Stress - 492 Type Mould, Broadside Mid-Height,Time = 720 Seconds 213A2.43 Von Mises Stresses near the Top of the 492 Mould 214A2.44 Von Mises Stresses near the Base of the 492 Mould 215A2.45 Von Mises Stress at Mid-Height, Time = 720 Seconds492 Mould 216A2.46 Von Mises Stress at the Base of the Mould492 Mould 217A2.47 Maximum Absolute Principal Stress at the Mid-Height,Time = 720 Seconds 492 Mould 218A2.48 Maximum Absolute Pricipal Stress at the Base,Time = 720 Seconds 492 Mould 219A2.49 Variation in with Position at Mid-Height,Time = 720Seconds 492 Mould 220A2.50 Variation in a with Position at Base, Time = 720Seconds 492 Mould 221A2.51 Von Mises Stress at a Height of 2.1685M fromBase of 492 Mould 222A2.52 Stress Contour Plot of the 492 Mould Top 223A2.53 Displacement of the Tl Mould Predicted by the PlasticityAnalysis after 720 Seconds 224A2.54 Displaced Shape (Dotted) for the Tl Mould after Coolingto Ambient Temperature 225A2.55 Finite Element Mesh for the Modified Tl Mould(Original Profile shown Dotted) 226A2.56 Maximum Absolute Principal Stress Contour - Tl Mould 227A2.57 Tl Mould, Mid-Height, Stress and Temperature ProfilesThrough the Mould Wall at the Point of Maximum Stress(Node 61) 228


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2B.1 Thermal Conductivity of Cast Iron 2292B.2 Schematic Diagram of a Section Through the Mould 2302B.3 Thermal Conductivity of Air at Atmospheric Pressure 2312B.4 Convective Heat Loss Coefficient as a Function ofWall Temperature 2322B.5 Radiative Heat Loss Coefficient as a Function of MouldWall Temperature 2332B.6 Specific Heat Capacity for Spheriodal Graphite andFlake Graphite Cast Irons 234


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ETABLISSEMENT DES PARAMETRES DE CONCEPTION RELATIFS AUX GRANDS MOULESA LINGOTINS DU TYPE BRAMEBritish Steel CorporationAcc ord CECA n 721 0 .C A/8 13Rsum:rapport technique finalNous avons tudi la mise au pointd'unemthode; d'analyse des contraintesthermiques lments finis qui servirait de procdure de conceptionrelative aux grands moules lingotins du type brame.Dans le cadre de ces travaux, les proprits physiques et mcaniquesde moules en acier, amens des tempratures leves pour les besoinsdu calibrage des modles, ont t dtermines en laboratoire.Une srie d'essais en usine a t effectue sur quatre types de moulesslectionns dans lesquels la distribution de la temprature l'intrieur des parois des moules, ainsi que le niveau de dformationconstat sur la surface ont t dtermins, depuis le dbut du coulagejusqu'au dmoulage des lingotins. La procdure d'analyse des contraintestheimigues lments finis exige que soit effectue pour commencerune analyse thermique provisoire lments finis permettant dedterminer les modifications chronologiques de la distribution de latemprature aprs quel'aciera t coul dans le moule lingotinsfroid; cette analyse prliminaire est suivied'uneanalyse descontraintes thermigues lments finis. La correspondance entreles tempratures obtenues en usine et celles prdites partir dumodle tait satisfaisante.La procdure de conception recommande a t formule sur la base descomparaisons effectues entre les niveaux de contrainte gnrs par lemodle et ceux constats dans un moule "de repre" dont la bonneperformance en usine tait connue. Parmi les tapes essentielles decette routine, citons (i) l'analyse prmiminaire bi-dimensionnellebon march des contraintes thermigues horizontales pouvant fournirdes principes utiles la conception, (ii) la drivationd'uneroutine d'analyse quasi tri-dimensionnelle bon march des contraintes(obtenue partir de la combinaison des analyses des contraintesverticales et horizontales) et la comparaison avecl'tude"de repre".L'analyse tri-dimensionnelle des contraintes thermiques est trscoteuse, mais recommande dans les cas o un moule a t conu defaon asymtrique, par exemple lorsqu'il n'y a un bord que sur lesfaces opposes du moule, la base.

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Page1. INTRODUCTION 12. DETERMINATION DES PROPRIETES MATERIELLES DE L'ACIER

COULE UTILISE POUR LES MOULES A LINGOTINS 22.1 Introduction 22.2 Prparation de blocs/chantillons d'essai 22.3 Dtermination des proprits matrielles par laBritish Cast Iron Research Association (B.C.I.R.A.) 3

2.3.1 Notes relatives la procdure d'essai 32.3.2 Discussion des proprits des blocs d'essai 43. DETERMINATION DES DIMENSIONS DES MOULES 5

3.1 Techniques de mesure conventionnelles 53.2 Mesure du profil intrieur des moules lingotinsau moyen d'un profilomtre de moule spcialementconstruit 54. REGLAGE DES APPAREILS DE MESURE DES MOULES A LINGOTINSPOUR LES ESSAIS EN USINE 6

4.1 Rglages requis des appareils de mesure des moules 64.2 Types de moules choisis pour les essais 64.3 Instrument de mesure de la temprature 64.4 Instrument de mesure de la contrainte 64.5 Dtails relatifs au rglage des appareils de mesuredes moules 74.6 Disposition des moules d'essai pendant le coulage 8

5. RESULTATS DES ESSAIS EFFECTUES AU MOYEN DES APPAREILS DEMESURE 85.1 492 moule troite ouverture (dure de vie moyenneen service 120 chaudes) 8

5.1.1 Mesures de la temprature du moule 85.1.2 Rsultats de la jauge de contrainte 95.1.3 Vrifications des dimensions du moule 95.2 T1 moule large ouverture (dure de vie moyenne dumoule en service 84 chaudes) 10

5.2.1 Mesures de la temprature du moule 105.2.2 Mesures de la jauge de contrainte 105.2.3 Vrifications des dimensions du moule 10

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5.3 U5 Moule troite ouverture (dure de vie moyennedu moule en service 96 chaudes) 115.3.1 Mesure de la temprature du moule 115.3.2 Mesures de la jauge de contrainte 115.3.3 Vrifications des dimensions du moule 11

5.4 V3/481 Moule large ouverture (dure de vie moyenne dumoule en service 103 chaudes) 125.4.1 Mesures de la temprature du moule 125.4.2 Mesures de la jauge de contrainte 125.4.3 Vrifications des dimensions du moule 12

5.5 Commentaires sur les valeurs de contrainte mesureset les modles de dfectuosit des moules 125.5.1 Contraintes mesures 125.5.2 Modles de dfectuosit des moules 13

6. ETUDES A ELEMENTS FINIS (sous-traitant: Design Audit Limited) 146.1 Aperu des tudes lments finis 146.2 Slection des moules 146.3 Drivation de la distribution de la temprature dansle moule 146.4 Drivation de l'analyse des contraintes thermiques 156.5 Moule 492 - Etudes du modle tri-dimensionnel 156.6 Moule T1 - Etudes de l'analyse des contraintesthermiques 16

6.6.1 Section horizontale mi-hauteur du moule T1 166.6.2 Moule T1 modifi 166.6.3 Effets de la plasticit du moule T1 166.7 Procdure de conception recommande 17

7. INFLUENCE DES DONNEES RELATIVES AUX PROPRIETES PHYSIQUESSUR LES NIVEAUX DE CONTRAINTE THERMIQUE CONSTATES SUR LEMOULE 492 177.1 Moule 492 Analyse bi-dimensionnelle partir desproprits du graphite spheroidal 18

7.1.1 Drivation de la distribution de la tempraturedans le moule 187.1.2 Analyse des contraintes thermiques 187.1.3 Moule 492 modifi 187.2 Moule 492 - Analyse bi-dimensionnelle partir desproprits du graphite compact 19

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8. CONCLUSIONS 19REFERENCES 20TABLEAUX 21FIGURES 49APPENDICES 11

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Liste des tableaux

7210.CA/81 3Page

1. Comparaison de la structure des moules d'essai et desblocs d'essai 212. Variation des modules d'lasticit et de conductivitthermigue des aciers-graphite compacts et sphrodes 223. Dtails des types de moules utiliss pour les essaisen usine 234. Profondeur des trous destins l'insertion desthermocouples 245. Mode de fixation des jauges de contrainte 25(commun aux quatre moules d'essai)6. Rsum des essais: type de moule: 492 267. Rsum des rsultats de la jauge de contrainte - moule 492valeur des contraintes et des dformations (maximum) 278. Rsum des rsultats de la jauge de contrainte - moule 492Valeur des contraintes et des dformations (0,2 heure) 289. Rsum des essais - type de moule: T1 2910.Rsum des rsultats de la jauge de contrainte - moule T1Valeur des contraintes et des dformations (maximum) 3011.Rsum des rsultats de la jauge de contrainte - moule T1Valeur des contraintes et des dformations (0,2 heure) 3112.Rsum des essais - type de moule: U5 3213.Rsum des rsultats de la jauge de contrainte - moule U5Valeur des contraintes et des dformations (maximum) 3314.Rsum des rsultats de la jauge de contrainte - moule U5Valeur des contraintes et des dformations (0,2 heure) 3415.Rsum des essais - type de moule: V3/481 35

16.Rsum des rsultats de la jauge de contrainte - moule V3/481Valeur des contraintes et des dformations (maximum) 3617.Rsum des rsultats de la jauge de contrainte - moule V3/481Valeur des contraintes et des dformations (0,2 heure) 3718.Rsum des rsultats de la jauge de contrainte - valeurmaximum des contraintes 3819.Caractristigues physigues utilises par Design Audit Limitedpour l'analyse des contraintes thermiques lments finissur le moule 492 ( troite ouverture) et le moule T1( large ouverture) 3920.Rsum des caractristiques physiques de l'acier-graphitespheroidal coul 4021.Moule 492 modle horizontal, distribution des dformations mi-hauteur des noeuds 4122.Moule 492 modle horizontal, distribution des dformations mi-hauteur des noeuds 4223.Rsum des caractristigues physigues - moule 492 modlehorizontal,enveloppe graphite compact, distribution desdformations - mi-hauteur 43Feuilles de calcul1 < 45

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Tables de l'appendiceA2.1 Moule 492 modle horizontal, distribution desdformations aux noeuds (mi-hauteur) 152A2.2 Concentration des dformations sur le coin dumoule de type 492 (mi-hauteur) 153A2.3 Donnes relatives au transfert de chaleur pourl'analyse axisymtrigue 154A2.4 Moule T1 , modle horizontal bi-dimensionnel,mi-hauteur, distribution des dformations aux noeuds 155A2.5 Concentration des dformations sur le coin du moulede type T1 (mi-hauteur) 156

Feuilles de calculs A2.1 - A2.15 157

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Listedesfigure s Page1. Endroito lesblocs d'chantillo nnage ont tdcoup sdanslesparois larges/troitesd'unmoule lingotins

de type561 492. Vued'ensemble desappareilsdemesureduprofildesfacesdumoule lingotins 503. Vue de ladispositi on avantdesappareilsdemesuredu profildumoule 514. Rel ati on nfcredformations app are nte set latemprature 525. Relation entrelechangementen dufacteurde jauge

etlatemprature 536. Mouletroite o uverture pour appareilsdemesure munisde thermocouples et dejaugesdecontrainte 547. Moule large ouverture pour appareilsdemesure munisde thermocouples et dejaugesdecontrainte 558. Vued'ensemble dumoul e avec a pparei lsdemesureet

botier isol destin auxinstruments 569. Mouledetype 492( 2)tro ite ouvertu re (canaux couplethermolectrique8 11)Emplacement -basede laparoitroite 5710.Moule de type 492 (2) troite ouverture (canaux couple

thermolectriques 12 15) Emplacement - mi-hauteur dela paroi troite 58

11. Mouledetype 492( 2) tro ite ouvert ure (canaux couplethermolectrique 16 18) Emplacement Baseducoin 5912. Mouledetype 492( 2)tro ite ouve rtur e (canaux couplethermolectrique 19 21)Emplacement -mi-hauteurducoin 6013. Mouledetype 492( 2)tro ite ouvert ure (canaux couplethermolectrique 22 25)Emplacement -Basede laparoi

large 6114.Moule de type 492(2) troite ouverture (canaux couplethermolectrigue 26 29) Emplacement - mi-hauteur de laparoi large 62

15. Mouledetype 492 (2)tro ite ouvertu re (canaux couplethermo lectrique 12 15)Emplacement -mi-hauteurde laparoi troite. 6316. Moule de type 492(2) troite ouverture (canaux couple

thermolectrique 26 29) Emplacement - mi-hauteur de laparoi large 64

17. Comaparaisondesmthodesdemesurede latempraturedela surface 65

18. Mouledetype 49 2. Etroit e ouve rtur e (Jaugedecontr aintecanal 1 -horizontal) Emplacement -mi-hauteurde laparoi troite 66

19. Mouledetype 492 . Etroi te ouvert ure (Jaugede contraintecanal4 -horizontal) Emplacement -mi-hauteurducoin 6720. Mouledetype 49 2. (Jaugedecontrainte canal6 -horizontal) Emplacement -mi-hauteurde laparo i large 6821. Dviationparrapportauxdimensions standard -paroi sintrieuresdumoul e:1. paroi intrieure nord- 492

2.paroi intrieure sud - 492 69

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22.Dviation par rapport aux dimensions standard - paroisintrieures du moule:1.paroi large ouest - 4922.paroi large est - 492 70

23.Moule de type (01) large ouverture (canaux couplethermolectrique 8 11) Emplacement - base de la paroitroite 71

24.Moule de type (01) large ouverture (canaux couplethermolectrique 12 15) Emplacement - mi-hauteur de laparoi troite 7225.Moule de type (01) large ouverture (canaux couplethermolectrique 16 18) Emplacement - base du coin 7326.Moule de type (01) large ouverture (canaux couplethermolectrique 19 21) Emplacement - mi-hauteur du coin 7427.Moule de type (01) large ouverture (canaux couplethermolectrique 22 25) Emplacement - base de la paroilarge 7528.Moule de type (01) large ouverture (canaux couplethermolectrique 26 29) Emplacement - mi-hauteur de laparoi large 7629.Moule de type (01) large ouverture (canaux couplethermolectrique 12 15) Emplacement - mi-hauteur de laparoi troite 7730.Moule de type (01) large ouverture (canaux couplethermolectrique 26 29) Emplacement - mi-hauteur de laparoi large 7831.Moule de type T1 large ouverture (jauge de contraintecanal 1 - horizontal) Emplacement - mi-hauteur d e la paroitroite 7932.Moule de type T1. Large ouverture (jauge de contraintecanal 4 - horizontal) Emplacement - mi-hauteur du coin 8033.Moule de type T1 . Large ouverture (jauge de contraintecanal 6 - horizontal) Emplacement - mi-hauteur de laparoi large 8134.Dviation par rapport aux dimensions standard - paroisintrieures du moule:1. Paroi troite nord - T1

2.Paroi troite sud - T1 8235.Dviation par rapport aux dimensions standard - paroisintrieures du moule:

1. Paroi large ouest - T12.Paroi large est - T1 8336.Moule de type (U5) Ouverture troite (canaux couplethermolectrique 8 11) Emplacement - base de laparoi troite 84

37.Moule de type (U5) Ouverture troite (canaux couplethermolectriqeu 12 15) Emplacement - mi-hauteurde la paroi troite 85

38.Moule de type (U5) Etroite ouverture (canaux couplethermolectrique 16 18) Emplacement - base du coin 86

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FR 95 6 831 7210.CA/81 339.Moule de type (U5) Etroite ouverture (canaux couplethermolectrique 19 21) Emplacement - mi-hauteur du coin 8740.Moule de type (U5) Etroite ouverture (canaux couplethermolectrique 22 25) Emplacement - Base de la paroi

large 8841.Moule de type (U5) Etroite ouverture (canaux couplethermolectrique 26 29) Emplacement - mi-hauteur de laparoi large 8942.Moule de type (U5) Etroite ouverture (canaux couplethermolectrique 12 15) Emplacement - mi-hauteur de laparoi troite 9043.Moule de type (U5) Etroite ouverture (canaux couplethermolectrique 26 29) Emplacement - mi-hauteur de laparoi large 9144.Moule de type (U5) Etroite ouverture (jauge de contraintecanal 1 - horizontal) Emplacement - mi-hauteur de la paroitroite 9245.Moule de type U5 Etroite ouverture (jauge de contraintecanal 4 -horizontal) Emplacement - mi-hauteur du coin 9346.Moule de type U5 Etroite ouverture (jauge de contraintecanal 6 - horizontal) Emplacement - mi-hauteur de laparoi large 9447.Dviation par rapport aux dimensions standard - paroisintrieures du moule:1. Paroi troite nord - U52.Parpi troite sud - U5 9548 Dviation par rapport aux dimensions standard - paroisintrieures du moule:1. Paroi large ouest - U52.Paroi large est - U5 9649.Moule de type 481(V3) Large ouverture (canaux couplethermolectrigue 8 11) Emplacement - base de la paroitroite 9750.Moule de type 481(V3) Large ouverture (canaux couplethermolectrique 12 15) Emplacement - mi-hauteur de laparoi troite 9851.Moule de type 481(V3) Large ouverture (canaux couplethermolectrique 16 18) Emplacement - base du coin 9952.Moule de type 481(V3) Large ouverture (canaux couplethermolectrique 19 21) Emplacement - mi-hauteur du coin 10053.Moule de type 481(V3) Large ouverture (canaux couplethermolectrigue 22 25) Emplacement - base de la paroi

large 10154.Moule de type 481(V3) Large ouverture (canaux couplethermolectrique 26 29) Emplacement - mi-hauteur de laparoi troite 10255.Moule de type V3 Large ouverture (jauge de contraintecanal 1 - horizontal) Emplacement - mi-hauteur de laparoi troite 10356.Moule de type V3 Large ouverture (jauge de contraintecanal 4 - horizontal) Emplacement - mi-hauteur du coin 104

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57.Moule de type V3 Large ouverture (jauge de contraintecanal 6 - horizontal) Emplacement - mi-hauteur de laparoi large 10558.Dviation par rapport aux dimensions standard - paroisintrieures du moule:1. Paroi troite nord - 481(V)2.Paroi troite sud - 481(V) 10659.Dviation par rapport aux dimensions standard - paroisintrieures du moule:1. Paroi large ouest - 481(V)2.Paroi large est - 481(V) 10760.Comparaison entre les valeurs de la dformation prdite etmesure (moule 49 2, mi-hauteur de la paroi troite) 10861.Dure de vie moyenne contre dformation maximum mesure mi-hauteur sur paroi troite des moules lingotinsde type 49 2, V4, U5 et T1 10962. Comparaison des valeurs de la dformation prdite etmesure (moule T 1, mi-hauteur de la paroi troite) 110

63.Gomtrie de la section horizontale mi-hauteur pourle moule de type 492 11164.Grille bi-dimensionnelle pour moule de type 492 11265.Profil de la temprature prdit par ordinateur pourle moule 492 aprs 720 secondes 11366.Moule 492, mi-hauteur de la paroi large - Rsultatsde la validation 11467. Comparaison entre les valeurs de la dformation prditeet mesure (moule 49 2, mi-hauteur de la paroi troite)(caractristiques thermiques del'aciercoul rvispour l'acier-graphite spheroidal) 11568.Comparaison entre les valeurs de la dformation prditeet mesure (moule 492 , mi-hauteur de la paroi troite) 116

Figures de 1'appendiceA1.1 Prparation spcimen provenant d'un chantillonemprunt l'acierdu moule lingotins 121A1.2 Rapport contrainte/dformation - Echantillon de laparoi large 122A1.3 Progression de l'expansion et de la contraction -20C - 900C - 20C- Echantillon de la paroi large 123A1.4 Microstructure provenant de l'chantillon de laparoi large (x20 grave 4% Picral) 124A1 .5 Rapport contrainte/dformation - chantillon de laparoi troite 125A1.6 Progression de l'expansion et de la contraction-20C - 900C - 20C Echantillon de la paroitroite 126A1.7 Microstructure provenant de l'chantillon de laparoi troite (x20 grave 4% Picral) 127

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A2.1 Dimensions du moule 492 troite ouverture 172A2.2 Dimensions du moule 481 (V3) large ouverture 173A2.3 Dimensions du moule U5 troite ouverture 174A2.4 Dimensions du moule T1 large ouverture 175A2.5 Moule de type 492(2) Etroite ouverture (canaux couple thermolectrique 8 11) Emplacement - basede la paroi troite 176A2.6 Moule de type 492(2) Etroite ouverture (canaux couple thermolectrique 12 15) Emplacement - mi -hauteur de la paroi troite 177A2.7 Moule de type 492(2) Etroite ouverture (canaux couple thermolectrique 22 25) Emplacement -base de la paroi large 178A2.8 Moule de type 492(2) Etroite ouverture (canaux couple thermolectrique 26 29) Emplacement -mi-hauteur de la paroi large 179A2.9 Gradients thermigues 180A2.10 Procdure de conception 181A2.11 Diagramme schmatigue d'une section du moule 182A2.12 Conductivit thermique del'air la pression

atmosphrique 183A2.13 Coefficient de perte de chaleur convective en tantque fonction de la temprature des";parois 184A2.14 Coefficient de perte de chaleur radiative en tantque fonction de la temprature des parois du moule 185A2.15 Profils de la temprature mi-hauteur de la paroilarge entre 0 et 1h - moule 492 186A2.16 Profils de la temprature mi-hauteur de la paroilarge entre 0 et 1h 187A2.17 Temprature moyenne du moule en tant gue fonctiondu temps - mi-hauteur de la paroi large 188A2.18 Temprature moyenne du moule en tant que fonctiondu temps - mi-hauteur de la paroi large 189A2.19 Capacit thermigue spcifigue de l'acier coul-graphite spheroidal et graphite en lames 190A2.20 Mi-hauteur de la paroi large du moule 492 - Rsultatsde la validation 191A2.21 Dimensions du moule de type 492 192A2.22 Gomtrie de la section horizontale mi-hauteurdu moule 492 193A2.23 Grille bi-dimensionnelle pour le moule de type 492 194A2.24 Profil de la temprature prdit par ordinateur aprs30 minutes - moule 492 195A2.25 La variation de 0,2% de la contrainte d'essai due la temprature 196A2.26 Dimensions du moule et de la plaque de supportutiliss lors de l'analyse axisymtrique - moule 492 197A2.27 Grille pour l'analyse axisymtrique - moule 492 198A2.28 Distribution de la temprature lors de l'analyseaxisymtrique, moule 492, mi-hauteur 199A2.29 Comparaison des contraintes horizontales - moule 492 180 secondes 200A2.30 Comparaison des contraintes horizontales - moule 492 720 secondes 201


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A2.31 Comparaison des contraintes horizontales - moule 492 3600 secondes 202A2.32 Contrainte principale absolue la plus grande aprs720 secondes 203A2.33 Gomtrie du moule T1 mi-hauteur 203A2.34 Grille lments finis pour le moule T1, mi-hauteur 204A2.35 Contrainte principale absolue maximum aprs 720secondes - moule T1 , mi-hauteur 205A2.36 Grille tri-dimensionnelle du moule 492 et de la plaquede support 207A2.37 Profils de la temprature pour la paroi large mi -hauteur du meule de type 492 208A2.38 Profils de la temprature pour la paroi troite mi -hauteur du moule de type 492 209A2.39 Profils de la temprature pour la paroi large, mi-hauteur, aprs 720 secondes - moule 492 210A2.40 Profils de la temprature pour la paroi troi te, mi-hauteur, aprs 720 secondes - moule 492 211A2.41 Contrainte de Von Mises - moule de type 49 2, paroitroite,mi-hauteur, dure=720 secondes 212A2.42 Contrainte de Von Mises - moule de type 49 2, paroilarge, mi-hauteur, dure=720 secondes 213A2.43 Contraintes de Von Mises prs du sommet du moule 492 214A2.44 Contraintes de Von Mises prs de la base du moule 492 215A2.45 Contrainte de Von Mises mi-hauteur, dure=720 sec.

moule 492 216A2.46 Contrainte de Von Mises la base du moule - moule 492 217A2.47 Contrainte principale absolue maximum mi-hauteur,dure=720 secondes, moule 492 218A2.48 Contrainte principale absolue maximum la base,dure=720 secondes, moule 492 219A2.49 Variation en avec emplacement mi-hauteur,dure=720 secondes, moule 492 220A2.50 Variation en avec emplacement la bas e,dure=720 secondes, moule 492 221A2.51 Contrainte de Von Mises une hauteur de2 1685M partir de la base du moule 492 222A2.52 Trac du contour de la contrainte - sommet du moule 492 223A2.53 Dplacement du moule T1 prdit par l'analyse deplasticit aprs 720 secondes 224A2.54 Forme (en pointills) du dplacement du moule T1aprs refroidissement la temprature ambiante 225A2.55 Grille lments finis pour le moule T1 modifi(profil d'origine reprsent en pointills) 226A2.56 Contour de la contrainte principale absolue maximum- moule T1 227A2.57 Moule T1, mi-hauteur, Profils de la contrainte et dede la temprature travers la paroi du moule au 228point de contrainte maximum (noeud 61)

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2B.1 Conductivit thermique de l'acier coul 2292B.2 Diagramme schmatique d'une section transversaledu moule 2302B.3 Conductivit thermique del'air la pressionatmosphrique 2312B.4 Coefficient de perte de chaleur convective en tantque fonction de la temprature des parois 2322B.5 Coefficient de perte de chaleur radiative en tantque fonction de la temprature des parois 2332B.6 Capacit thermique spcifique des aciers couls-graphite spheroidal et graphite en lames 234

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Erarbeitung von Entwurfsparametern fr groe BrammenkokillenBritish Steel CorporationEKSG Vertrag Nr. 7210.CA/81 3

Zusammenfassung: Technischer SchluberichtEine Untersuchung fr die Entwicklung einer finiten Elementsmethode derthermischen Beanspruchungsanalyse fr Verwendung als ein Entwurfsverfahrenfr groe Brammenkokillen ist durchgefhrt worden.Als Teil dieser Untersuchung sind die physikalischen und mechanischenEigenschaften des Kokilleneisens im Labor bis zu erhhten Temperaturen hinfr Eichung des Modells bestimmt worden. Eine Reihe von Versuchen imBetrieb wurden mit vier ausgewhlten Kckillentypen durchgefhrt, in denendie Temperaturverteilungen innerhalb der Kokill.enwandstrke und dem Oberflchenspannungsausma vom Beginn des Vollgieens bis zum Abziehen derBrammen aus den Kokillen gemessen wurden. Fr die finite Elementsmethodeder thermischen Beanspruchungsanalyse ist eine einleitende, vorbergehende,thermische, finite Elementsanalyse ntig, um zu bestimmen, wie sich dieKokillentemperaturverteilungen mit der Zeit ndern, nachdem der Stahlin die kalte Brammenkokille gegossen worden ist, und diesem mu einefinite Elementsanalyse der thermischen Beanspruchung folgen. Man konntegute bereinstimmung zwischen den im Betrieb gemessenen Temperaturen unddenen gewinnen, die mit dem Modell vorhergesagt wurden.Man hat ein Entwurfsverfahren fr Empfehlung formuliert, das sich auf denVergleich der Beanspruchungsausmae sttzt, die vom Modell und denen einerVergleichskokille mit einer bekannten, guten Betriebsleistung erzeugtwerden. In den wesentlichen Stadien dieser Routine wurden die folgendenPunkte erfat: (i) die einleitende, rationelle, zweidimensionale,horizontale, thermische Beanspruchungsanalyse, die in ntzlichen Entwurfsrichtlinien resultieren kann, (ii) die Ableitung einer rationellen, quasidreidimensionalen Beanspruchungsanalyseroutine, (die man durch Verbindungder horizontalen und senkrechten 2-dimensionalen Analysen gewinnt) undder Vergleich mit der Untersuchung der Vergleichskokille. Die 3-dimen-sionale,thermische Beanspruchungsanalyse, die sehr teuer ist , wird in denFllen empfohlen, wo ein Kokillenentwurf unsymmetrische Merkmale aufweist,das wre zum Beisp iel, wenn ein Mantel nur auf den gegenberliegendenFlchen der Kokille unten angebracht wrde.

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Inhaltsverzeichnis Seite1. Einleitung 12. Bestimmung der Werkstoffeigenschaften der gueisernen 2Brammenkokillen

2.1 Einleitung 22.2 Vorbereitung der Versuchsblcke/-proben 22.3 Bestimmung der Werkstoffeigenschaften durch die 3British Cast Iron Research Association (BritischeForschungsgesellschaft fr Gueisen, B.C.I.R.A.)2.3.1 Aufzeichnungen des Versuchsverfahrens 32.3.2 Besprechung der Eigenschaften der 4

Versuchsblcke3. Bestimmung der Kokillendimensionen 5

3.1 Herkmmliche Meverfahren 53.2 Messung des internen Profils der Brammenkokillen mit 5Hilfe der speziell konstruierten Kokillenprofilme-instrumente.4. Instrumentierung der Brammenkokillen fr Versuche im Betrieb 6

4.1 Bedarf an Kokilleninstrumentierung 64.2 Fr den Versuch gewhlte Kokillentypen 64.3 Temperaturmeinstrumente 64.4 Spannungsmeinstrumente 64.5 Einzelheiten der Kokilleninstrumentierung 74.6 Anordnung der Versuchskokillen whrend dem Gieen 85. Ergebnisse der instrumentierten Kokillenversuche 8

5.1 492 Flaschenhalskokille (durchschnittliche Kokillen- 8haltbarkeit im Betrieb, 120 Erwrmungen)5.1.1 Messungen der Kokillentemperaturen 85.1.2 Dehnungsmesserergebnisse 95.1.3 Dimensionale berprfung der Kokillen 9

5.2 Tj offene Kokille (durchschnittliche Kokillenhaltbar- 10keit im Betrieb, 84 Erwrmungen)5.2.1 Messung der Kokillentemperaturen 105.2.2 Dehnungsmessermessungen 105.2.3 Dimensionale berprfung der Kokillen 10

5.3 U5 Flaschenhalskokille (durchschnittliche Kokillen- 11haltbarkeit im Betrieb, 96 Erwrmungen)5.3.1 Messung der Kokillentemperaturen 115.3.2 Dehnungsmessermessungen 115.3.3 Dimensionale berprfung der Kokillen 11

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5.4 V3/48I offene Kokille (durchschnittliche Kokillenhalt- 12barkeit im Betrieb, 103 Erwrmungen5.4.1 Messung der Kokillentemperaturen 125.4.2 Dehnungsmessermessungen 125.4.3 Dimensionale berprfung der Kokillen 12

5.5 Stellungsnahme zu den gemessenen Spannungswerten 12und den Versagensmustern der Kokillen5.5.1 Gemessene Spannungen 125.5.2 Versagensmuster der Kokillen 13

6. Finite Elementsuntersuchung (als Nebenvertrag an die 14Firma Design Audit Limited vergeben)6.1 berblick der finiten Elementsuntersuchungen 146.2 Kokillenauswahl 146.3 Ableitung der Temperaturverteilung in der Kokille 146.4 Ableitung der thermischen Beanspruchungsanalyse 156.5 492 Kokille - 3-dimensionale Modelluntersuchungen 156.6 Ti Kokille, Untersuchung der thermischen Beanspruchungs- 16analyse

6.6.1 Kokille, horizontaler Querschnitt an der 16mittleren Hhe6.6.2 Modifizierte Tj Kokille 166.6.3 Ti Kokille, Auswirkung der Plastizitt 166.7 Empfohlenes Entwurfsverfahren 17

7. Einflu der physikalischen Eigenschaftsdaten auf die 17thermischen Beanspruchungsausmae der 492 Kokille7.1 492 Kokille, 2-dimensionale Analyse unter Einsatz 18von sphroidischen Graphiteigenschaften

7.1.1 Ableitung der Temperaturverteilung in der 18Kokille7.1.2 Thermische Beanspruchungsanalyse 187.1.3 Modifizierte 492 Kokille 187.2 492 Kokille, 2-dimensionale Analyse - kompakt 19gemachte Graphiteigenschaften

8. Schlufolgerungen 19Literaturverzeichnis 20Tabellen 21Abbildungen 49Anhnge 117

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Aufstellung der Tabellen Seite1. Vergleich zwischen dem Gefge der Versuchskokillen und 21den Testblcken2. Abweichung des Elastizittsmoduls und der thermischen 22Leitfhigkeit fr sphroidische und kompakt gemachteGraugueisen3. Einzelheiten der in den Betriebsversuchen benutzten 23Kokillentypen4. Tiefe der Lcher fr Einsatz der Thermoelemente 245. Befestigungsmethode der Dehnungsmesser 25(gleich fr alle vier Versuchskokillen)6. Zusammenfassung der Versuche - Kokillentyp 492 267. Zusammenfassung der Dehnungsmesserergebnisse - 492 Kokille 27

Spannungs- und Beanspruchungswerte (maximum)8. Zusammenfassung der Dehnungsmesserergebnisse - 492 Kokille 28Spannungs- und Beanspruchungwerte (0,2 Stunden)9. Zusammenfassung der Versuche - Kokillentyp Ti 29Zusammenfassung der Dehnungsmesserergebnisse - Ti Kokille 30Spannungs-und Beanspruchungswerte (maximum)Zusammenfassung der Dehnungsmesserergebnisse - Ti Kokille 31Spannungs- und Beanspruchungswerte (0,2 Stunden)Zusammenfassung der Versuche - Kokillentyp U5 32Zusammenfassung der Dehnungsmesserergebnisse - U5 Kokille 33Spannungs- und Beanspruchungswerte (maximum)Zusammenfassung der Dehnungsmesserergebnisse - U5 Kokille 34Spannungs- und Beanspruchungswerte (0,2 Stunden)Zusammenfassung der Versuche - Kokillentyp V3/48I 3516. Zusammenfassung der Dehnungsmesserergebnisse - V3/48I Kokille 36Spannungs-und Beanspruchungswerte (maximum)17. Zusammenfassung der Dehnungsmesserergebnisse - V3/48I Kokille 37Spannungs- und Beanspruchungswerte (0,2 Stunden)18. Zusammenfassung der Dehnungsmesserergebnisse - Maximale 38Spannungswerte19. Von der Firma Design Audit Limited benutzte physikalische 39Eigenschaften fr die finite Elementsanalyse der thermischen Beanspruchung in den 492 (Flaschenhals) und Ti(offener^ Kokillen

20. Zusammenfassung des sphroidischen Graphitgusses - 40physikalische Eigenschaften des Eisens21. 492 Koki lle, horizontales Modell, Beanspruchungsverteilung 41an den Knoten, mittlere Hhe22. 492 Koki lle, horizontales Modell, Beanspruchungsverteilung 42an den Knoten, mittlere Hhe23. Zusammenfassung der physikalischen Eigenschaften - 43kompakt gemachter Graphitgu24. 492 Kokille, horizontales Modell, Beanspruchungsverteilung, 44mittlere Hhe

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Anhang der Tabellen SeiteA2.1 492 Kokille, horizontales Modell, Beanspruchungs- 152Verteilung an den Knoten (mittlere Hhe)A2.2 Beanspruchungskonzentration am Eckpunkt der Kokille 153

Typ 492 (mittlere Hhe)A2.3 Wrmebertragungsdaten fr die axisymmetrische Analyse 154A2.4 Ti Kokille, 2-dimensionales, horizontales Mode ll, 155mittlere Hh e, Beanspruchungsverteilung an den KnotenA2.5 Beanspruchungskonzentration am Eckpunkt der Kokille 156Typ Ti (mittlere Hhe)

Berechnungsbogen A2.1 - A2.15 157

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Aufstellung der Abbildungen Seite1.2.3.4.5.6.7.8.9.10.11.12.13.14.15.16.17.18.19.20.21.

22.

23.24.25.26.

Position, wo die Probenblcke von den breiten, schmalen 49Wnden der Brammenkokille Typ 561 geschnitten wurdenAllgemeine Ansicht der Instrumente fr Messung des Profils 50der BrammenkokillenflchenAnsicht der Mekopfanordnung der Meinstrumente fr das 51KokillenprofilVerhltnis zwischen der anscheinenden Spannung und der 52TemperaturVerhltnis zwischen der % Vernderung des Eichfaktors und 53der TemperaturFlaschenhalskokille, fr Instrumentierung mit Thermoelementen 54und DehnungsmessernOffene Kokille fr Instrumentierung mit Thermoelementen und 55DehnungsmessernAllgemeine Ansicht der instrumentierten Kokille und des 56isolierten Gehuses fr die InstrumenteKokillentyp 492 (2) - Flaschenhals (Thermoelementkanle 578 bis 11) Lage - unten an der Schmalwand(2) - Flaschenhals (Thermoelementkanle 58- mittlere Hhe der Schmalwand(2) - Flaschenhals (Thermoelementkanle 5916 bis 18) Lage - unten am EckpunktKokillentyp 492 (2) - Flaschenhals (Thermoelementkanle 60- mittlere Hhe am Eckpunkt(2) - Flaschenhals (Thermoelementkanle 61- unten an der Breitwand

(2) - Flaschenhals (Thermoelementkanle 62- mittlere Hhe der Breitwand(2) - Flaschenhals (Thermoelementkanle 63- mittlere Hhe der Schmalwand(2) - Flaschenhals (Thermoelementkanle 64- mittlere Hhe der BreitwandVergleich zwischen den Memethoden der Oberflchentemperatur 65Kokillentyp 492, Flaschenhals (Dchnungsmcsscrkanal 1 - 66- mittlere Hhe der SchmalwandFlaschenhals (Dehnungsmesserkanal 4 - 67horizontal) Lage - mittlere Hhe am EckpunktKokillentyp 492 , Flaschenhals (Dehnungsmesserkanal 6 - 68horizontal) Lage - mittlere Hhe der BreitwandAbweichung von den normalen Dimensionen - interne Kokillenwnde1. schmale Nordwand - 492 692.schmale Sdwand - 492Abweichung von den normalen Dimensionen - interne Kokillenwnde1. breite Westwand - 4922.breite Ostwand - 492 Kokillentyp (Ol),offen (Thermoelementkanle 8 bis 11) 71Lage - unten an der SchmalwandKokillentyp (Ol),offen (Thermoelementkanle 12 bis 15) 72Lage - mittlere Hhe der SchmalwandKokillentyp (Ol ), offen (Thermoelementkanle 16 bis 18) 73Lage - unten am EckpunktKokillentyp (Ol ), offen (Thermoelementkanle 19 bis 21) 74Lage - mittlere Hhe am Eckpunkt

Kokillentyp 49212 bis 15) LageKokillentyp 492

19 bis 21) LageKokillentyp 49222 bis 25) LageKokillentyp 49226 bis 29) LageKokillentyp 49212 bis 15) LageKokillentyp 49226 bis 29) Lage

horizontal) LageKokillentyp 492 ,

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FR 95 6 831 7210.CA/81327.Kokillentyp (Ol), offen (Thermoelementkanle 22 bis 25) 75Lage - unten an der Breitwand28.Kokillentyp (Ol), offen (Thermoelementkanle 26 bis 29) 76Lage - mittlere Hhe der Breitwand29.Kokillentyp (Ol), offen (Thermoelementkanle 12 bis 15) 77Lage - mittlere Hhe der Schmalwand30.Kokillentyp (Ol), offen (Thermoelementkanle 26 bis 29 78

Lage - mittlere Hhe der Breitwand31.Kokillentyp 1 - offen (Dehnungsmesserkanal 1 - 79horizontal) Lage - mittlere Hhe der Schmalwand32.Kokillentyp Tl - offen (Dehnungsmesserkanal 4 - 80horizontal) Lage - mittlere Hhe am Eckpunkt33.Kokillentyp Tl - offen (Dehnungsmesserkanal 6 - 81horizontal) Lage mittlere Hhe der Breitwand34.Abweichung von den normalen Dimensionen - interne Kokillenwnde1. schmale Nordwand - Ti Q O2.schmale Sdwand - Ti35.Abweichung von den normalen Dimensionen - interne Kokillenwnde1. breite Westwand - Ti2.breite Ostwand - Ti36.Kokillentyp (U5) - Flaschenhals (Thermoelementkanle 8 bis 11) 84Lage - unten an der Schmalwand37.Kokillentyp (U5) - Flaschenhals (Thermoelementkanle 12 bis 15) 85Lage - mittlere Hhe der Schmalwand38.Kokillentyp (U5) - Flaschenhals (Thermoelementkanle 16 bis 18) 86Lage - unten am Eckpunkt39.Kokillentyp (U5) - Flaschenhals (Thermoelementkanle 19 bis 21) 87Lage - mittlere Hhe am Eckpunkt40.Kokillentyp (U5) - Flaschenhals (Thermoelementkanle 22 bis 25) 88Lage - unten an der Breitwand

41.Kokillentyp (U5) - Flaschenhals (Thermoelementkanle 26 bis 29) 89Lage - mittlere Hhe der Breitwand42.Kokillentyp (U5) - Flaschenhals (Thermoelementkanle 12 bis 15) 90Lage - mittlere Hhe der Schmalwand43.Kokillentyp (U5) - Flaschenhals (Thermoelementkanle 26 bis 29) 91Lage - mittlere Hhe der Breitwand44.Kokillentyp U5, Flaschenhals (Dehnungsmesserkanal 1 - 92horizontal) Lage - mittlere Hhe der Schmalwand45.Kokillentyp U5, Flaschenhals (Dehnungsmesserkanal 4 - 93horizontal) Lage - mittlere Hhe am Eckpunkt46.Kokillentyp U5, Flaschenhals (Dehnungsmesserkanal 6 - 94horizontal) Lage - mittlere Hhe der Breitwand47.Abweichungen von den normalen Dimensionen - interne Kokillenwnde1. schmale Nordwand - U52.schmale Sdwand - U5 9548.Abweichungen von den normalen Dimensionen - interne Kokillenwnde1. breite Westwand - Us 962.breite Ostwand - U549.Kokillentyp 481 (V3), offen (Thermoelementkanle 8 bis 11) 97Lage - unten an der Schmalwand50.Kokillentyp 481 (V3), offen (Thermoelementkanle 12 bis 15) 98Lage - mittlere Hhe der Schmalwand51.Kokillentyp 481 (V3), offen (Thermoelementkanle 16 bis 18) 99

Lage - unten am Eckpunkt.52.Kokillentyp 481 (V3), offen (Thermoelementkanle 19 bis 21) 100Lage - mittlere Hhe des Eckpunktes53.Kokillentyp 481 (V3), offen (Thermoelementkanle 22 bis 25) 101Lage - unten an der Breitwand xxxvi


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54.Kokillentyp 481 (V3), offen (Thermoelementkanle 26 bis 29) 102Lage - mittlere Hhe der Breitwand55.Kokillentyp V3 , offen (Dehnungsmesserkanal 1 - 103horizontal) Lage - mittlere Hhe der Schmalwand56.Kokillentyp V3 , offen (Dehnungsmesserkanal 4 - 104horizontal) Lage - mittlere Hhe des Eckpunktes57.Kokillentyp V3 , offen (Dehnungsmesserkanal 6 - 105horizontal) Lage - mittlere Hhe der Breitwand58.Abweichung von den normalen Dimensionen - interne Kokillenwnde1. schmale Nordwand - 481 (V)2. schmale Sdwand - 481 (V)

10759.Abweichung von den normalen Dimensionen - interne Kokillenwnde1. breite Westwand - 481 (V)2.breite Ostwand - 481 (V)60.Vergleich zwischen den vorhergesagten und gemessenen 108Spannungswerten (492 Kokil le, mittlere Hhe der Schmalwand)61.Durchschnittliche Haltbarkeit gegen die maximal gemessene 109Spannung an der mittleren Hhe der Breitwand der Brammenkokillen Typ 492, V4, U5 und Tl62.Vergleich der vorhergesagten und gemessenen Spannungswerte 110(Tl Kokille, mittlere Hhe der Schmalwand)63.Geometrie des horizontalen Querschnittes an der mittleren 111Hhe fr die Kokille Typ 49264. 2-dimensionales Gradnetz fr die Kokille Typ 492 11265. Mit dem Rechner vorhergesagtes Temperaturprofil fr die 492 113Kokille nach 720 Sekunden66.492 Koki lle, mittlere Hhe der Breitwand - Gltigkeits- 114ergebnisse67.Vergleich der vorhergesagten und gemessenen Spannungswerte 115(492 Kokille, mittlere Hhe der Schmalwand - revidiertethermische Eigenschaften des Kokilleneisens frsphroidische Graphiteisen)68.Vergleich der vorhergesagten und gemessenen Spannungswerte 116(492 Koki lle, mittlere Hhe der Schmalwand)Anhang der AbbildungenAl.l Vorbereitung der aus dem Brammenkokilleneisen abgenommenen 121ProbeAl.2 Beanspruchungs/Spannungsverhltnis - Breitwandprobe 122AI.3 Ausdehnungs-und Kontraktionsweiterentwicklung - 20C - 123900C - 2O 0C, BreitwandprobeAI.4 Mikrogefge der Breitwandprobe (x 20 getzt, 4% Pikral) 124AI.5 Beanspruchungs/Spannungsverhltnis - Schmalwandprobe 125AI.6 Ausdehnungs-und Kontraktionsweiterentwicklung - 20C - 1269OO 0C - 20C, SchmalwandprobeAI.7 Mikrogefge der Schmalwandprobe (x 20 getzt, 4% Pikral) 127A2.1 Dimensionen der 492 Flaschenhalskokille 172A2.2 Dimensionen der offenen 481 (V3) Kokille 173A2.3 Dimensionen der U5 Flaschenhalskokille 174A2.4 Dimensionen der offenen Tl Kokille 175A2.5 Kokillentyp 492(2) - Flaschenhals (Thermoelementkanle 1768 bis 11) Lage - unten an der SchmalwandA2.6 Kokillentyp 492(2) - Flaschenhals (Thermoelementkanle 17712 bis 15) Lage - mittlere Hhe der Schmalwand

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FR 95 6 831 7210.CA/813A2.7 Kokillentyp 492(2) - Flaschenhals (Thermoelementkanle 17822 bis 25) Lage - unten an der BreitwandA2.8 Kokillentyp 492(2) - Flaschenhals (Thermoelementkanle 17926 bis 29) Lage - mittlere Hhe der BreitwandA2.9 Thermische Geflle ISOA2.10 Entwurfsverfahren 181A2.11 Schematisches Diagramm eines Querschnittes durch die 182KokilleA2.12 Thermische Leitfhigkeit der Luft bei lOOO bar 183A2.13 Konvektiver Wrmeverlustkoeffizient als eine Funktion 184der WandtemperaturA2.14 Strahlungswrmeverlustkoeffizient als eine Funktion der 185WandtemperaturA2.15 Temperaturprofile der Breitwand an der mittleren Hhe fr 1860 - 1st, 492 KokilleA2.16 Temperaturprofile der Breitwand an der mittleren Hhe fr 1871 - lOst, 492 KokilleA2.17 Durchschnittliche Kokillentemperatur als eine Funktion 188der Zeit - mittlere Hhe der BreitwandA2.18 Durchschnittliche Kokillentemperatur als eine Funktion 189der Zeit - mittlere Hhe der BreitwandA2.19 Spezifisches Wrmevermgen fr sphroidisches Graphit und 190Flockenrisse - GraphitgueisenA2.20 Kokille 492, mittlere Hhe der Breitwand - Gltigkeits- 191ergebnisseA2.21 Dimensionen der Kokille Typ 492 192A2.22 Geometrie des horizontalen Querschnittes an der mittleren 19 3Hhe fr die Kokille 492A2.23 2-dimensionales Gradnetz fr die Kokille Typ 492 194A2.24 Mit dem Rechner vorhergesagtes Temperaturprofil nach 19530 Minuten, 492 KokilleA2.25 Abweichung der 0,2%. Elastizittsgrenze durch die 196TemperaturA2.26 Dimensionen der in der axisymmetrischen Analyse benutzten 197Kokille und Grundplatte, 492 KokilleA2.27 Gradnetz fr die axisymmetrische Analyse, 492 Kokille 198A2.28 Temperaturverteilung fr die axisymmetrische Analyse der 199492 Kokille, mittlere HheA2.29 Vergleich der horizontalen Beanspruchungen - 492 Kokille 200bei 180 SekundenA2.30 Vergleich der horizontalen Beanspruchungen - 492 Kokille 201

bei 720 SekundenA2.31 Vergleich der horizontalen Beanspruchungen - 492 Kokille 202bei 3600 SekundenA2.32 Grte, absolute Hauptbeanspruchung nach 720 Sekunden - 203492 KokilleA2.33 Geometrie der Tl Kokille an der mittleren Hhe 204A2.34 Fintes Elementsgradnetz fr die Tl Kokille, mittlere Hhe 205A2.35 Maximale, absolute Hauptbeanspruchung nach 720 Sekunden, 206Tl Kokille, mittlere HheA2.36 3-dimensionales Gradnetz fr die 492 Kokille und 207GrundplatteA2.37 Temperaturprofile der Breitwand an der mittleren Hhe fr 208die Kokille Typ 492

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FR 95 6 831A2.38 Temperaturprofile der Schmalwand an der mittleren Hhefr die Kokille Typ 492A2.39 Temperaturprofile der Breitwand am Mittelpunkt fr dieKokille Typ 492 nach 720 SekundenA2.40 Temperaturprofile der Schmalwand am Mittelpunkt fr die

Kokille Typ 492 nach 720 SekundenA2.41 Von Mises Beanspruchung - 492 Kokillentyp, Schmalwand,mittlere Hhe, Zeit = 720 SekundenA2.42 Von Mises Beanspruchung - 492 Kokillentyp, Breitwand,mittlere Hhe, Zeit = 720 SekundenA2.43 Von Mises Beanspruchungen dicht am Hals der 492 KokilleA2.44 Von Mises Beanspruchungen dicht am Fu der 492 KokilleA2.45 Von Mises Beanspruchung an der mittleren Hhe, Zeit = 720Sekunden, 492 KokilleA2.46 Von Mises Beanspruchung unten an der 492 KokilleA2.47 Maximale, absolute Hauptbeanspruchung an der mittlerenHhe,Zeit = 720 Sekunden, 492 KokilleA2.48 Maximale, absolute Hauptbeanspruchung unten, Zeit = 720Sekunden, 492 KokilleA2.49 Abweichung des durch die Position an der mittlerenHhe,Zeit = 720ZSekunden, 492 KokilleA2. 50 Abweichung des durch die Position unten, Zeit = 720Sekunden, 492 KonilleA2.51 Von Mises Beanspruchung bei einer Hhe von2.168mvom Fuder 492 KokilleA2.52 Beanspruchungskonturdiagramm des 492 KokillenhalsesA2.53 Verlagerung der Tl Kokille mit der Plastizittsanalysenach 720 Sekunden vorhergesagtA2.54 Verlagerte Form (gepunktet) der Tl Kokille nach Abkhlung

in RaumtemperaturA2.55 Finites Elementsgradnetz fr die modifizierte Tl Kokille(Originalprofil wird als gepunktet gezeigt)A2.56 Maximale, absolute Hauptbeanspruchungskontur - Tl KokilleA2.57 Tl Kokille, mittlere Hhe, Beanspruchungs- und Tempera-profile durch die Kokillenwand zur Zeit der maximalenBeanspruchung (Knoten 61)2B.1 Thermische Leitfhigkeit des Gueisens 2292B.2 Schematisches Diagramm eines Querschnittes durch die 230Kokille2B.3 Thermische Leitfhigkeit der Luft bei 1000 bar 2312B.4 Konvektiver Wrmeverlustkoeffizient als eine Funktion 232der Wandtemperatur2B.5 Strahlungswrmeverlustkoeffizient als eine Funktion der 233Kokillenwandtemperatur2B.6 Spezifisches Wrmevermgen fr sphroidisches Graphit 234und Flockenrisse - Graphitgueisen

7210.CA/813209210211212213214215216217218219220221222223224225226227228

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ESTABLISHMENT OF DESIGN PARAMETERS FOR LARGE SLAB TYPE INGOT MOULDSBritish Steel CorporationECSC Agreement No. 7210.CA/813Final Technical Report.

1. INTRODUCTIONWhen considering the performance of ingot moulds, it has become increasinglyapparent over the recent years that there are significant benefits to be gained inusing iron types other than the conventional flake graphite iron. In addition toa large amount of experience with the use of flake graphite iron moulds, theBritish Steel Corporation has also had considerable experience with the use ofcompacted graphite irons, mainly for medium and large slab type ingot moulds andwith spheroidal graphite iron, mainly for small square section moulds.Plant trials have shown that ingot mould designs developed for flake graphite ironare in many cases not suitable to take maximum advantage of the improved materialproperties of the other types of iron and there is great scope for increases inaverage mould life and reductions in mould iron costs per tonne of steel produced.Studies carried out previously in BSC have been concerned with specific moulddesigns in flake graphite iron. The advantages of compacted graphite irons, interms of mould life, have already been established in a trial with 500 moulds ofseveral types conducted within the Corporation. However, it is evident that therelationship between mould design, microstructure and usage conditions isimportant in designing moulds for a specific application and that scope exists forthe further improvement of mould iron consumption by establishing the correctdesign criteria for such irons.The objective of this research programme was to establish design parameters forlarge slab type ingot moulds, primarily for moulds made from compacted graphiteiron, by means of plant and laboratory studies, with the aim of calibrating andadapting a finite element stress analysis package to establish a design procedure.The work programme carried out for this project was as follows:-(i) Determination of Properties (Section 2)Laboratory measurements of physical and mechanical properties of mould iron up toelevated temperatures were carried out by the British Cast Iron ResearchAssociation and their results are detailed in Appendix 1.(ii) Determination of Mould Dimensions (Section 3)The main dimensions were derived from the foundry engineering drawings and furtherchecks were made on trial moulds prior to plant usage. Additional mould profilemeasurements were made during the course of the trials.(iii) Instrumentation of Moulds for Trials (Section 4)The four mould types chosen for the trials, the selection of temperature andstrain measuring equipment, mould instrumentation procedures and the arrangementsfor carrying out the trials in the steelworks teeming and stripping bays aredescribed.


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(iv) Resu lts of Instr umente d Mould Trials (Sections 5)Thirty -three instrumented mould plant trials were carried out. Details of mouldtemperature and strain measurements are given.(v) Finite Element- Stud ies (Sections 6 and 7)Design Audit Limited were sub-contracted to interpret the practical results of themould trials and the material properties data using finite element computerpackag es to establish mould thermal stres ses and develop a procedure for thedesign /modifi cation of ingot mould s. The results of this work are discussed inSection 6 of this report, and the derivation of the design procedure is given indetail in Appendix 2. Additio nal Welsh Laboratory studies are given in Section 7.The original Technical Annex for this research programme included the followingadditional items which have not been studied.(a) The extens ion of a 2-D finite differ ence th ermal model for the pred ictio n of

temperature gradients through the mould wall.(b) The feasibility of including fracture mechanics c alculatio ns in the finiteelement model, for prediction of failure mechanisms.(c) Metall ographi c examinat ions of trial moulds after failure to establishchanges in microstructure.It was not possible to include the above in the work programme due to the reducedfunding and time scale allocated to this project.2. DETERMINA TION OF MATERI AL PROPERTIES FOR INGOT MOULD CAST IRON2.1. IntroductionLiterature surveys established that there was little published data on propertiesfor compacted grap hite irons so it was decided to obtai n test blocks of thatmaterial and have property determinations carried out by "The British Cast IronResearch Association" on a sub-contract basis.The material properties required were:-(i) Tensile tests , including stress/strain curves.(ii) Modu lus of elas ticity(iii)Density(iv) Poissons Ratio(v) Thermal conductivity(vi) Coef fici ent of linear thermal e xpan sion(vii)Specific heatThe test blocks were to be obtained from a mould which had been s crapped at thefound ry. Occasi onal ly a newly cast mould is scrapped du e to a part ial run-out ofmeta l from the sand mould or a shortage of liquid iron to complete the castin g.In this situation the mould material is of good quality , but the dimen sionalrequirements are not achieved.Other met hods of obtainin g test blo cks , e.g.casting them at the foundry wereconsidered to be unsatisfactory as there would be little chance that they would berepresentative of the structure and properties of an actual mould.2.2. Preparat ion of Test Blocks/S amplesThe mould that the samples were obtained from was a 561 type, scrapped because ofa shor t-fa ll in the amount of liquid iron required to compl ete the cast ing. Thi smould had been allowed to cool normally in its box and sand jacket so the ironstructure would be expected to be as for a normal ingot mould.


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Using a special oxy-acetylene burner at 'Gabelin' Works, Ebbw Vale, suitable testblocks were obtained about 400mm 400mm the mould wall thickness. The blockswere cut from the centre area of one broad face and one narrow face of the mould,see Fig.l. These positions should be representative for this mould as a whole asregards structure and properties.The blocks were reduced by milling and cutting on a mechanical saw to 300mm 300mm mould wall thickness which ensured that the heat affected zone due to theburning process was completely removed. The test blocks were then despatched tothe British Cast Iron Research Association for cutting up and testing.Table 1 gives a comparison of the structures of the four moulds used for the planttrials and the test blocks. The ultra-sonic velocity test resultsi 1) indicatedthat the test block material and one of the trial moulds were largely spheroidalgraphite and the other three trial moulds were largely compacted graphite.The ultra-sonic velocity test is a non-destructive testing method for thedetermination of the graphite form in cast iron. Typical velocity figures (km/s)for different iron types are as follows:Flake graphite iron - less than 4.9Compacted graphite iron - 4.9 to 5.2Spheroidal graphite iron - 5.3 or greaterThese figures are approximate as they can vary slightly with section thickness.Although it was intended to measure properties for compacted graphite test blocksthe spheroidal graphite blocks were used because it was considered unlikely atthat time that further material would be obtainable due to the depressed state ofthe UK Iron and Steel Industry. This was borne out by events. The properties ofspheroidal graphite iron are nearer to those for compacted graphite than to thosefor flake graphite iron and even though a lot of information is available on theproperties of spheroidal graphite iron in general, little data exists on theproperties of spheroidal graphite ingot mould irons.2.3. Material Property Determinations by British Cast Iron Research Association(B.C.I.R.A.)The results of material properties from the two test blocks are detailedin Appendix 1.2.3.1. Notes on Test Procedures(i) Tensile TestsThe tests were carried out on standard test bars of0.798inches diameter(20.296mm) to British Standards specification BS.1452/1961 - Testing of grey ironcastings. The maximum test temperature was limited to 800C.Above this temperature the plasticity of the test specimen is too high for thetest to proceed. Due to the coarse graphite structure the results show a fairlylow tensile strength and elongation for this type of iron.(ii) Modulus of ElasticityThe two results, at 20C, were calculated from stress/strain data and sonicresonance data, the latter method, developed by BCIRA, gives the most accurateresults. After subsequent discussions with BCIRA, recommended values were alsoobtained for the likely variation of Modulus of Elasticity with temperature, forspheroidal graphite iron. Additional information on the variation of modulus ofelasticity with temperature for compacted graphite iron was obtained from aBritish Steel Corporation source (see Table 2).


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(iii) DensityThis was determined at 20C by direct measurement using standard apparatus.(iv) Ultrasonic VelocityThis test, developed by BCIRA, gives an indication of the graphite form in thecast iron. The quoted values confirmed that the graphite form of the two testblocks was largely spheroidal.(v) Poisson's RatioThis was an estimated value (at 20C) from a search of published data.(vi) Thermal ConductivityThe values were determined by the BCIRA standard test employing the guard tubemethod. The maximum temperature was limited to 500C to avoid significantstructural changes due to heating of the test pieces. Additional information onthe variation of thermal conductivity with temperature for compacted graphite ironwas obtained from recently published work by BCIRA and is shown together with themean values for the test blocks in Table 2.(vii) Coefficient of Linear Thermal ExpansionThe BCIRA standard method was employed based on the use of a dilatometer. Themaximum test temperature was restricted to 600C due to limitations of theequipment used.(viii) Specific HeatThe BCIRA standard method was used employing the guard tube technique. Furtherdetails of this test are given in Appendix 1. The maximum test temperature was900C.2.3.2. Discussions on Properties of Test BlocksSince the test block iron structure was largely spheroidal graphite the testresults only represent the structure of the Us trial mould.The structures of the 492, Ti and V3/481 trial moulds were largely compactedgraphite. The implications of this are discussed below. The properties whichwould be expected to be significantly different for the two iron types are tensileproperties, modulus of elasticity and thermal conductivity.(i) Tensile TestsThe tensile test results for the spheroidal graphite test pieces were relativelylow for this type of material. The test block samples showed a tensile strengthof 305 N/mm2with 2% elongation, however, the range of properties for ingot mouldspheroidal graphite cast iron can extend to about 425 N/mm 2 tensile strength and8% elongation depending upon the composition and structure of the iron. Thetensile properties of the test blocks can be regarded as being more typical ofcompacted graphite than spheroidal graphite iron.(ii) Modulus of ElasticityValues for compacted graphite iron are lower than those for spheroidal graphiteiron and are given in Table 2.(iii) DensityDensity would be expected to be very similar for both types of iron.


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(iv) Ultrasonic VelocityThe ultrasonic velocity would be expected to be lower for compacted graphite iron.(v) Poisson's RatioThis would be expected to be similar for both types of iron.(vi) Thermal ConductivityThermal conductivity values for compacted graphite iron are higher than those ofspheroidal graphite iron due to the interconnection of the graphite flakes.Values are given in Table 2.(vii) Coefficient of Linear Thermal ExpansionThis would be expected to be very similar for both types of iron.(viii) Specific HeatThis would be expected to be very similar for both types of iron.3. DETERMINATION OF MOULD DIMENSIONS3.1. Conventional Measuring TechniquesThe nominal mould dimensions were obtained from the foundry engineering drawings.The inner and outer dimensions at the base and top of trial moulds, height, walland corner thicknesses were checked using a steel measuring tape. A simplecaliper device was used to obtain wall thickness measurements at 450 mm from thebase. In the case of bottle top moulds, expanding steel measuring rods were usedto check the inside dimensions near the top of the mould at a point where thecross-section changes to the bottle-top shape. Results are given in Section 5 ofthe report.3.2. Measurement of Internal Profile of Ingot Moulds using Specially ConstructedMould Profilometer Equipment

(i) Description of EquipmentThis equipment was manufactured in the Welsh Laboratory Workshop specifically foruse on this project, to measure profiles during the mould life cycle.The equipment comprises a 2.75 m long rigid beam along which is traversed (bychain and sprocket drive) a block to which is clamped a 20 mm diameterdisplacement transducer fitted with a wheel type follower. The beam is levelledby means of jacks and positioned by adjustable bracing arms. The transducer isthen traversed along the mould wall and the signal passed to a pen recorder whichrecords the surface profile. Fig. 2 shows a general view of the equipment andFig. 3 the measuring head. The equipment is electrically operated via a motorand gearbox and requires a 240v supply. The equipment is capable of measuring themould profile to within0.1mm.i i) Method for Measuring Mould Profile

The mould to be measured is laid down on its side (normally broad wall down forstability reasons) and the profilometer is positioned and suitably braced on thecentre line of the wall facing the ground. The aim is for the transducer totraverse along a measured distance from as near to one end as possible (the openend in the case of a bottle top mould) to as near as possible to the other end ofthe mould (in the case of a bottle top the end of the straight portion).A suitable speed and sensitivity is selected and after a dummy run the transduceris traversed over the measured distance, starting the pen chart when it reachesthe start point and stopping the pen when it reaches the end point. By


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disconnecting the transducer and mounting it in the opposite direction the sameprocedure can be used to obtain a profile of the face above. The profilometer isthen re-positioned to enable a trace to be carried out on each of the narrow facesin turn. Results are discussed in Section 5 of this report.4. INSTRUMENTATION.OF INGOT MOULDS FOR PLANT TRIALS4.1. Requirements for Mould InstrumentationThe aim of the plant trial work was to attach thermocouples and strain gauges toingot moulds and to continually measure temperatures and strains developed duringplant usage cycles. Trials would be conducted where the ingot was left in themould to cool to low temperature and where the mould was stripped from the ingotas in normal practice. These measurements would be supplemented by furthertemperature measurement of the outer mould surfaces using "AGA" Thermovision andThermoprofile cameras and 'Land' Gold Cup thermometers and pyrometers.The measured values of temperature and strain would be used to calibratemathematical models for deriving temperature and stress and profiles which couldthen be used to establish design parameters for ingot moulds.4.2. Mould Types Chosen for TrialFour different mould types were chosen for the trial, two open top moulds and twobottle top moulds. Details of mould dimensions, mould life and modes of failureare shown in Table 3. Note the difference in aspect ratio for these moulds. The492 mould gives the best plant performance (Aspect ratio 1.32) with the major modeof failure being crazing of the inner walls. The Ti mould gives the poorestperformance (Aspect ratio1.70),the major modes of failure being horizontalcracking on the broad walls associated with inwards distortion of the broad wallsin many cases. All four mould types have the lifting lugs on the broad walls andthe broad walls face outwards on the casting bogies.4.3. Temperature Measuring Equipment(i) ThermocouplesThe aim was to have thermocouples sited on the outside surface of the mould, inthe mid-thickness of the wall and 6mm from the inner face.The thermocouples used were 3mm diameter type "K" (nickel chromium versus nickelaluminium) 25/20 stainless steel sheathed, magnesium oxide insulated, withinsulated junctions and hglazed seals to BS4937,Part 4, and BS1041. Thesurface mounted thermocouples were 1.5mm diameter. Holes of4.5mmdiameter weredrilled in the moulds to allow the insertion of the thermocouples at depths fromthe outer face of approximately 25mm, 110mm and in the case of the broad andnarrow wall positions to within about 6mm of the inner face, see Table 4.i i)Additional Temperature Measuring Equipment'Land' Gold Cup Thermometers and Pyrometers were used for external temperaturemeasurements on the trial moulds. An AGA Thermovision camera was used to obtain athermal picture of the outside surfaces of the trial mould. Two different lenseswere used a 10angle and a 25angle of view. Instant thermograms were obtainedusing an autocolour attachment with Polaroid colour film packs. An AGAThermoprofile camera was used to obtain reference temperatures for calibration ofthe thermograms. Both of these cameras could be operated using a mains supply orwith portable generators.4.4. Strain Measuring EquipmentAs a pre-requisite to the use of strain gauges, particularly for high temperatureapplications it is essential to obtain as much information as possible on theperformance of the gauges and the correct method of application of the gauges tostructural surfaces. The choice of high temperature strain gauges which are


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commercially available is limited. The full bridge gauge selected was supplied byBaldwin, Lima, & Hamilton Electronics, U.S.A. The gauge is of the electricalresistance type on a weldable steel shim with an operating range of up to 650C.Tests have been conducted to determine temperature compensation required undertransient heating conditions (with gauges attached to test pieces of cast iron)i.e. apparent strain induced by the differential thermal expansion between thegauge and the structure to which it is attached and the change in resistivity ofthe strain gauge grid conductor with temperature. Strain gauges were spot weldedto a test block of compacted graphite iron (dimensions 50 100 x25mm). Theassembly was subjected to three repeated heating and cooling cycles (temperaturerange ambient to 565C) in a laboratory electrical resistance furnace. Therelationship established between apparent strain and temperature is shown in Fig.4. Correction factors for apparent strain variation with temperature and gaugefactor variation with temperature are applied to the total strain measured by thestrain gauge, to give the true strain. The gauge factor at ambient temperature wasestablished by using a four point bending beam. This value was lower than themanufacturer's quoted figure. The gauge factor (K) is defined as the relationshipbetween the resistance change and the change in strain in a resistance straingauge and is expressed as:

K - -R where R is the initial resistance of the installed gauge and L is the initiallength of the installed gauge.The change in gauge factor with temperature was by reference to the manufacturer'sspecification and confirmed via communication with other users (CentralElectricity Generating Board, Berkeley Nuclear Laboratories and InternationalResearch and Development, Newcastle-Upon-Tyne). The relationship betweenpercentage change in gauge factor with temperature is illustrated inFig.5.4.5. Mould Instrumentation DetailsThe number of thermocouples and strain gauges that can be used for plant trials islimited by the type of data logger used. A Solartron compact logger 3430A wasselected. The unit is small, robust, and easily transportable and has theadvantage of being powered by internal re-chargeable batteries or mains supply.The logger can accept 30 analogue inputs and can accommodate seven different typesof standard thermocouples. Cold junction compensation is automatically applied tothe linearisation calculation. The logger can accept any combination ofthermocouple or strain gauge inputs. Thermocouple outputs are in degreescentigrade and strain gauge outputs in volts. Measured data is recorded on acomputer compatible magnetic tape cassette.It was decided that the best system would be to have 22 thermocouples and 8 straingauges at three positions near the base of the mould and three positions at themid-height of the mould (see Figures 6 and 7 ) . The strain gauges were to beattached near to the positions of the thermocouples.To obviate the effect of variable residual stresses which may be present in themoulds as delivered from the foundry, the four trial moulds were subjected to onenormal usage cycle before being instrumented.Each strain gauge was given a laboratory stabilization cycle prior to plantinstallation. This involved tack welding each gauge to a cast iron block andheating to 565C with a 24 hour soak. The strain gauges were then spot welded atthe six different locations in the horizontal plane of the mould and twoadditional gauges were mounted in the vertical plane at the broad and narrow wallmid height positions, see Table 5. The orientation of the gauges was based uponthe knowledge that when moulds fail by cracking it is predominantly for verticalcracking at mid-wall position at the base or top and in some cases horizontalcracks form at mid height on the broad walls.


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4.6. Arrangements of Trial Moulds during CastingTrials were carried out at two steelplants, Llanwern and Port Talbot. Thecast weight at Port Talbot is 320 tonnes and 180 tonnes at Llanwern. Thelayout of the mould on the ingot bogie and the method of carrying out the trialswas similar for both plants. Fig.8 being typical, shows the layout for the 492mould at Port Talbot.The trial mould was placed at one end of the bogie on its base plate. The rest ofthe bogie was taken up by a bottle top mould laid on its side. This mould wasused to house the instruments which had to be kept at a temperature below 25C andwas covered with a thick layer of mineral insulating blanket with an outercovering of stainless steel sheeting secured by steel bands.The multicore high temperature insulated leads from the instruments were threadedthrough flexible galvanised steel conduit and connected at the mould end via aninsulated junction box with ceramic connectors to the thermocouples and straingauges.The flexible umbilical lead was 20m in length to allow for the mouldto be stripped from the ingot and placed on the ground until the ingot had beenremoved. This arrangement worked satisfactorily as long as reasonable care wastaken and meant that there was no interruption to data recording at stripping.The trial bogie was

Slab Ingot Mould Design CDNA09087ENC_001

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