Oxidation and decarburisation of high carbon steels

Directorate-General For Research And Innovation European Commission

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• Sciences et techniques

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• Publié par: DIRECTORATE-GENERAL-FOR-RESEARCH-AND-INNOVATION-EUROPEAN-COMMISSION
• Nombre de lectures: 39
• Langue: English
• Poids de l'ouvrage: 4 Mo

Extrait

EURO PEAN
COMMISSION
SCIENCE
RESEARCH
DEVELOPMENT
technical steel research
Mechanical working (rolling)
Oxidation and
decarburisation
of high carbon steels
h
Report
EUR 18408 EN STEEL RESEARCH EUROPEAN COMMISSION
Edith CRESSON, Member of the Commission
responsible for research, innovation, education, training and youth
DG Xli/C.2 — RTD actions: Industrial and materials technologies —
Materials and steel
Contact: Mr H. J.-L. Martin
Address: European Commission, rue de la Loi 200 (MO 75 1/10),
áfl B-1049 Brussels — Tel. [phone]; fax [phone] European Commission
?'·. E ¡i ΐ' '";
Mechanical working (rolling)
Oxidation and decarburisation
of high carbon steels
H. F. Marston, A. J. Rose, R. E. Abbott, M. Bugdol, W. Richardson
British Steel pic
9, Albert Embankment
London SE1 7SN
United Kingdom
Contract No 7210-EC/804
1 July 1993 to 30 June 1996
Final report
Directorate-General
Science, Research and Development
1998 EUR 18408 EN LEGAL NOTICE
Neither the European Commission nor any person acting on behalf of the Commission
is responsible for the use which might be made of the following information.
A great deal of additional information on the European Union is available on the Internet.
It can be accessed through the Europa server (http://europa.eu.int).
Cataloguing data can be found at the end of this publication.
Luxembourg: Office for Official Publications of the European Communities, 1998
ISBN 92-828-4548-6
© European Communities, 1998
Reproduction is authorised provided the source is acknowledged.
Printed in Luxembourg
PRINTED ON WHITE CHLORINE-FREE PAPER CONTENTS
Page
NOMENCLATURE 11
1. INTRODUCTION H
1.1 General Background n
1 2 Theoreticald3
1.3 Material for Investigation
2. DECARBURISATION AT TEMPERATURES BELOW 1000°C 14
2.1 Background 1
2.2 Preliminary Decarburisation Trials
2.3 Decarburisation Under Scale-Free Conditions 17
COATING AND TRAMP ELEMENT TESTS
21
3.1 Background 21
3.2 The Effect of Tramp Element Additions 22
3.3 Trials with Coatings4
THERMO-GRAVIMETRIC OXIDATION TESTS 25
4.1 Description of the Gravimetric Oxidation Unit (Thermobalance) 25
4.2 Furnace Calibration and Atmosphere Control6
4.3 Calculation of Gas Requirement for Oxidation 2
4.4 Thermo-Gravimetric Tests 3
4.5 Assessment of Thermobalance Test Results - Gravimetric Results 33
4.6t ofe Tests - Decarburisation7
4.7 Correlation between Gravimetry and Decarburisation Measurements 3
4.8 Metallographic Examination of Scale from Thermo-Gravimetric Tests9
PLANT TRIALSg
6. CONCLUSIONS 41
6.1 General Basis of the Project 41
6.2 Decarburisation of Duplex Structures, Below 1000°C 4
6.3 Coatings, Tramp Elements, Silicon and Chromium2
6.4 Thermogravimetric Testing
6.5 Plant Trials4
7. ACHIEVEMENT OF OBJECTIVES
REFERENCES 45
TABLES7
FIGURES 51
APPENDIX 1 TECHNICAL ANNEX 129 LIST OF TABLES
1. Composition of Steel Samples
2.n of Gaseous Atmospheres
3. Matrix of Completed Thermo-Gravimetric Tests Experimental Conditions for Base
0.75% C Steel and Cu and Ni Bearing Variants
4. Matrix of Completedc Tests for Low and High Silicon 0.75% C
Steel, Cu and Ni Bearing Variants, and Razor Steel
LIST OF APPENDICES
1. Technical Annex - Objective and Structure of Research - Oxidation and
Decarburisation of High Carbon Steels LIST OF FIGURES
1. Ishikawa Diagram Summarising Scheme of Oxidation and Decarburisation Project
2. Effect of Local Scale Adherence on Extent of Decarburisation at 800°C
(a) Limited Decarburisation in Area with Adherent Scale
(b) Significant Intergranular Decarburisation in Area with Poorly Adherent,
Modified Scale
3. The Activity of Carbon in Solid Fe-C Alloys (from Smith'2')
4. Equilibrium Carbon Content of Fe-C Alloy at Metal-Scale Interface at Given Carbon
Monoxide Partial Pressure
5. Predicted Interface Carbon Content for C-FeO-CO Reaction pco = 1 Atmosphere
6. Apparatus for Controlled Atmosphere Heat Treatments
7. Initial Results from Decarburisation in N2 - H2 Atmosphere
(a) Decarburisation at Low Temperatures for Initial Trials
(b) Arrhenius Plot for Low Temperature Decarburisation
8. Banding in Specimen Decarburised 5 h at 700°C in N2-H2 Atmosphere
(a) Side Parallel to Working Texture
(b) Side Transverse to Working Texture
9. X-Ray Scans for Mn, Si and C Perpendicular to Edge Shown in Fig. 8(a)
10.y Scans for Mn, Si and C Parallel to Edge Shown in Fig. 8(b)
11. Trial Results for Decarburisation in N2-H2 Atmosphere with Reduced Jetting
(a) Effect of Nickel
(b) Effect of Silicon
12. Compilation of all Results for Decarburisation in N2-H2 Atmosphere
13. Criteria for Decarburisation with 90% N210% H2 Atmosphere
14. Measurement Locations on 20 χ 25 mm Section of Cuboid Samples
15. Effect of Steel Composition on Scale Thickness
(a) 1100°C
(b) 1200°16. Effect of Steel Composition on Decarburisation
(a) 1100°C
(b) 1200°C
17. Effect of Copper and Nickel on Low Temperature (930°C) Decarburisation
(a) 3 min
(b) 10 min
(c) 20 min
18. Effect of Coatings'K'on Scaling
(a) 1100°C
(b) 1200°C
19. Effect of Coatings 'K' on Decarburisation
(a) 1100°C
(b) 1200°C
20. Assessment of Alternative Coatings at 1200°C
(a) Scale Development (Metal Loss)
(b) Decarburisation
21. Visual Appearance of Coated Samples after Reheating
22. Schematic Diagram of Gravimetric Oxidation Rig (Thermobalance)
23. Thermobalance Furnace Calibration
(a) Temperature Profile
(b) Oxygen Profile with Argon Atmosphere
24. Gas Equilibrium: Oxygen Potential
25.s: Combusted Natural Gas with 1% Excess 02
(a) H2:H20 Equilibrium
(b) CO:C02
26. Gas Requirement for Oxidation: 0.2% C in Combined Natural Gas (1% Excess 02)
(a) Control by FeO
(b)l by Fe304
(c)l by Fe203 27. Scaling Rate Constants for Alternative Sample Geometries after Progressive Heating
to1300°C
(a) 0.2% C Steel
(b) 0.5% NiCr Steel
28. Gas Consumption Relative to Gas Required to Form Fe203
(a) 0.2% C Steel
(b) 0.5% NiCr Steel
29. Superimposed Temperature Profiles for Thermobalance Tests
(a) Soaked at 1100°C (54 lines)
(b)d at 1300°C (40 lines)
30. Decarburised Zone on Samples Heated to 1000°C - Based Steel
(a) Code B0B1 -10°C/min - BOS + 1 % Residual 02
(b)e C0N6 - 2.5°C/min - Natural Gas + 6% Residual 02
31. Progress of Weight Gain on Heating from 400 to 900°C or 1000°C at 20°C/min,
5°C/min or 1.25°C/min and Holding for 60 min
32.s of Weight Gain on Heating from 400 to 1000°C at 10°C/min or 2.5°C/min
and Holding for 60 min
33. Progress of Weight Gain on Heating from 400 to 1100°C at 20°C/min, 5°C/min or
1.25°C/min and Holding for 60 min
34.s of Weight Gain on Heating from 400 to 1100°C at 10°C/min or 2.5°C/min
and Holding for 60 min
35. Progress of Weight Gain on Heating from 400 to 1200°C at 20°C/min, 5°C/min or
1.25°C/min and Holding for 60 min
36.s of Weight Gain on Heating from 400 to 1200°C at 10°C/min or 2.5°C/min
and Holding for 60 min
37. Progress of Weight Gain on Heating from 400 to 1300°C at 20°C/min, 5°C/min or
1.25°C/min and Holding for 60 min
38.s of Weight Gain on Heating from 400 to 1300°C at 10°C/min or 2.5°C/min
and Holding for 60 min
39. Comparison of Thermobalance Data for Samples Heated to 1000°C in BOS Gas
Atmospheres
40.n of Thermobalance Data for Samples Heated to 1000°C in Coke Oven
Gas Atmospheres 41. Comparison of Thermobalance Data for Samples Heated to 1200°C in BOS Gas
Atmospheres
42.n of Thermobalance Data for Samples Heated to 1200°C in Coke Oven
Gas Atmospheres
43. Comparison of Thermobalance Data for Samples Heated to 1300°C in BOS Gas
Atmospheres
44.n of Thermobalance Data for Samples Heated to 1300°C in Coke Oven
Gas Atmospheres
45. Effect of Alternative Humidification Techniques - Base Steel
46.t of Alternativens - 0.25% Cu
47. Effect of Atmospheric Oxygen Content - Natural Gas, 1100°C
48.t ofc Oxygen Content - Natural Gas, 1300°C
49. Effect of Atmospheric Oxygen Content - Sulphur-Free Oil, 1100°C
50. The Effect of Copper and Nickel on Scale Formation
(a) Top Surface - Low Si+CuNi Steel heated at 5°C/min to 1100°C in coke oven
gas, showing occlusions in scale
(b) Bottom Surface - Low Si+CuNi Steel heated at 5°C/min to 1100°C in coke
oven gas, showing occlusions in scale
(c) Side Face - Low Si+CuNi steel heated at 20°C/min to 1100°C in raw coke
oven gas with 1% excess oxygen, showing grain boundary penetration
51. Effect of Sulphur in the Furnace Atmosphere for Thermobalance Tests, Heated to
1100°C(Oil)
52. Effect of Sulphur in the Furnace Atmosphere for Thermobalance Tests, Heated to
1300°C(Oil)
53. Effect of Sulphur in