Design Project Presentation Slides

1. DESIGN OF AN
ELECTRIC FURNACE
FOR MAKING STEEL
BY GROUP 23 :
EUGENE TEO GUO SHUN 061933G07
KENVIN TEO SHI YU 061932E07
JOELTEE HAN YUN 060420D07
FIZH TO CHUN YU 060324H07

2. MS 3005 DESIGN PROJECT
List of Contents
 1. INTRODUCTION
 2. MOTIVATION
 3. SCOPE
 4. CURRENT OPERATION OF MAKING STEEL
 5. LITERATURE REVIEW
 6. WHY STAINLESS STEEL?
 7. MATERIALS SELECTION
 8. DISCUSSIONS
 9. RECOMMENDATIONS
 10. REVIEW
 11. QUESTIONS AND ANSWERS

3. MS 3005 DESIGN PROJECT
Introduction
 Steel making can be separated into two categories- primary and
secondary
 Current trend – using of electric arc furnace (EAF)
 Advantages
 400 tons of steel in 60 minutes
 Mass production= low price
 Flexible in stopping according to demand
 Disadvantages
 Environmental and efficiency
 Cost

4. MS 3005 DESIGN PROJECT
Motivation & Scope
 The growing Steel processing industry
 The gist of making stainless steel lies in the decarburization process.
 2 types of decarburization processes
 Vacuum oxygen decarburization (VOD)
 Argon oxygen decarburization (AOD)
 hassle of transferring to another ladle
 focus on improving and redesigning two aspects of the existing electric
arc furnace
 1. The process of vacuum decarburization
 2. The stirring of the molten steel to obtain a homogenous melt.

5. MS 3005 DESIGN PROJECT
Current Operation of Making Steel
Video

6. MS 3005 DESIGN PROJECT
Literature Review
 DESIGN OF AN ELECTRIC
FURNACE FOR MAKING
STEEL
Our group is going to focus on
improving the design and
manufacturing stainless steel using
the Electric Arc Furnace

7. MS 3005 DESIGN PROJECT
Literature Review
Methods of making steel (Christopher 2007)
 Hits
 Focuses on the method of making steel using an electric arc furnace
 Manage to come out with an invention make steel at a reduced cost
 Generation of source of lime compacted to form a conglomeration of
compacts; charged to the furnace in the shortest period of time to
avoid energy loss
 Misses
 Did not explain how different kinds of steel, like stainless steel, are
made directly from the electric arc furnace

8. MS 3005 DESIGN PROJECT
Literature Review
Making of stainless steel without using electric arc furnace (Clifford 1971)
 Hits
 patented a design which allowed them to produce stainless steel
without the use of an Electric Arc Furnace
 Misses
 Uses 2 channel furnaces
 A channel furnace is employed to mix chromium containing and
chromium-free hot metal, producing a converter feed metal of desired
temperature and chemical composition.

9. MS 3005 DESIGN PROJECT
Literature Review
 Making of stainless steel with an electric arc furnace without using
secondary processes (Arturo 1991)
 Hits
 identified the problems and enhanced the added oxygen process to
obtain good reducing conditions
 Installation of devices + lance system to introduce oxygen to improve
efficiency
 Misses
 Never looked into reducing the loss of chromium + homogenization of
melt

10. MS 3005 DESIGN PROJECT
Literature Review
 Electromagnetic Stirring
 Commonly used in continuous casting of metals
 Prevents the creation of inhomogeneous steel
 It agitates the molten core
 Balances the temperature gradient between the outer shell and inner
core of casted metal
 Feasible in homogenizing the stainless steel melt in the steel making
process

11. MS 3005 DESIGN PROJECT
Why Stainless Steel?
 WHAT is Stainless Steel?
 Low carbon steel alloy, 10 wt% of chromium by mass, chromium oxide
layer
Advantages
 1. Corrosion resistance
 2. Fire & Heat Resistance
 3. Hygiene
 4. Aesthetic appearance
 5. Strength-to-weight advantage
 6. Ease of fabrication
 7. Impact Resistance
 8. Long term value

12. MS 3005 DESIGN PROJECT
Materials Selection
 Stainless Steel chosen for the roof of electric arc furnace typically
Properties considered
 1. Melting point - high
 2. Fracture Toughness - high
 3. Specific Heat Capacity - high
 4. Thermal Expansion coefficient - high
 5. Thermal Conductivity – high
 Total number of decisions = N(N-1)/2 = 5(4)/2 = 10 decisions
 Weighting factors method
 Gathered data from CES software located at MSE computer lab
 Scaled data according to criterion
 Calculate Performance index

13. MS 3005 DESIGN PROJECT
Materials Selection
Table 1 Application of Digital Logic Method
Property Decision Number
1 2 3 4 5 6 7 8 9 10
Melting Point 1 1 1 1
Fracture
0 0 1 0
Toughness
Specific Heat
1 1 0 0
Capacity
Thermal
Expansion 1 0 1 0
Coefficient
Thermal
0 1 0 0
Conductivity

14. MS 3005 DESIGN PROJECT
Materials Selection
Table 2 Weighting Factors
Property Positive Decisions Weighting Factors
Melting Point 4 0.4
Fracture Toughness 1 0.1
Specific Heat Capacity 2 0.2
Thermal Expansion Coefficient 2 0.2
Thermal Conductivity 1 0.1
Total 10 1

15. MS 3005 DESIGN PROJECT
Materials Selection
Table 3 Property of Candidate Materials for EAF
Fracture Specific Heat Thermal Expansion Thermal
Material Melting Point °F Toughness Capacity Coefficient µ Conductivity
ksi.in^1/2 BTU/lb.F strain/°F BTU.ft/h.ft^2.F
Wrought 418 Martensite
Stainless Steel, tempered at 2597 24.57 0.1075 5.00E+00 13.29
260degC
Wrought 403 Ferritic Stainless
2597 47.32 0.1075 5.56E+00 13.29
Steel, intermediate temper
Wrought 202 Austenitic Stainless
2552 61.88 0.117 9.17E+00 8.667
Steel, annealed
Wrought 301 Austenitic Stainless
2552 61.88 0.1149 9.00E+00 9.013
Steel
Wrought 301 Precipitation
2552 61.88 0.1149 9.00E+00 9.013
Hardening Stainless Steel
Cast Duplex Stainless Steel CD-
2660 46.41 0.1075 5.56E+00 8.667
4CU

16. MS 3005 DESIGN PROJECT
Materials Selection
 As stainless steels are chosen commonly as roof material for the
typical electric arc furnace, 5 classes of stainless steels are chosen to
be analyzed.
Table 4 Scaled Values of properties and performance index Performance
Scaled (1) Scaled (2) Scaled (3) Scaled (4) Scaled(5)
Wrought 418 Martensite Stainless
39.05 3.97 20 10.91 10 83.93
Steel, tempered at 260degC
Wrought 403 Ferritic Stainless Steel,
39.05 7.65 20 12.12 10 88.82
intermediate temper
Wrought 202 Austenitic Stainless
38.38 10 21.77 20 6.52 96.66
Steel, annealed
Wrought 301 Austenitic Stainless
38.38 10 21.38 19.64 6.78 96.17
Steel
Wrought 301 Precipitation Hardening
38.38 10 21.38 19.64 6.78 96.17
Stainless Steel
Cast Duplex Stainless Steel CD-4CU 40 7.5 20 12.12 6.52 86.14
 Wrought 202 Austenitic Stainless Steel, annealed, should be chosen to
be made as the roof of electric arc furnace.

17. MS 3005 DESIGN PROJECT
Discussions - Vacuum Oxygen Decarburization
Concept
 To produce large steel ingots, rails, ball bearings and other high quality
steels.

18. MS 3005 DESIGN PROJECT
Discussions - Vacuum Oxygen Decarburization
Concept
 The oxidation of liquid steel components under the influence of
vacuum would result in the oxygen being used up mainly by the
reaction [C] + [O] = {CO}
 Use of Ellingham diagram

19. MS 3005 DESIGN PROJECT
Discussions - Vacuum Oxygen Decarburization
Concept
 A plot of Gibbs Free Energy ΔG against temperature.
 The Ellingham diagram shown is for metals which react with oxygen to
form oxides.
 The position of the line for a given reaction on the Ellingham diagram
shows the stability of the oxide as a function of temperature.

20. MS 3005 DESIGN PROJECT
Discussions - Vacuum Oxygen Decarburization

21. MS 3005 DESIGN PROJECT
Discussions - Vacuum Oxygen Decarburization
Concept
 Carbon unusually useful as a reducing agent.
 Ellingham Diagram
 This process helps to decarburize the steel with minimum chromium
losses.
 Complete deoxidizers  then desulfurizing slag
 Problem?

22. MS 3005 DESIGN PROJECT
Discussions - Vacuum Oxygen Decarburization
Design of the Furnace in incorporating an extensible roof with vacuum
 Combine step of Vacuum Oxygen Decarburization

23. MS 3005 DESIGN PROJECT
Discussions - Vacuum Oxygen Decarburization
Design of the Furnace in incorporating an extensible roof with vacuum
 2 roofs which are interchangeable
 Simultaneous addition of oxygen
 Use of Vacuum
 Eliminates the need for another furnace

24. MS 3005 DESIGN PROJECT
Discussions - Electromagnetic Stirring
Importance of Stirring the Molten Melt
 Homogenizing of molten melt
 Improving heat and mass transfer rates
 Reduce processing times
 Metallurgical restrictions

25. MS 3005 DESIGN PROJECT
Discussions - Electromagnetic Stirring
Current Practice: Gas Stirring
 Use of Inert gases
Vacuum
 2 commonly used methods: Pump Outlet
Ladle Lid
 gas valve
 semi permeable refractory material
Safety
Height
Molten Steel Refractory
Material and
Ladle Wall
Porous Plug
Gas Injection or valve for
System gas injection

26. MS 3005 DESIGN PROJECT
Discussions - Electromagnetic Stirring
Disadvantages of Gas Stirring
 Additional processing step
 Cost
 Inability to cut off gas flow
 Violent turbulence
 Dangerous ejection of the melt

27. MS 3005 DESIGN PROJECT
Discussions - Electromagnetic Stirring
Proposed solution: Electromagnetic stirring
 Applied in continuous casting processes
 Non-invasive
 Adjustable stirring strength
 Simplifies furnace process
 Variable stirring pattern

28. MS 3005 DESIGN PROJECT
Discussions - Electromagnetic Stirring
Electromagnetic stirring: Working principle
Three Phase
Power Supply

29. MS 3005 DESIGN PROJECT
Discussions - Electromagnetic Stirring
Electromagnetic stirring: 2 proposed solutions
 Installation of stirrers at top of furnace
 Installation of stirrers at side of furnace

30. MS 3005 DESIGN PROJECT
Discussions - Electromagnetic Stirring
Proposed solution 1: Installation of Inductor at top of furnace
Top
Ring
Furnace
Lid
Energizing
(toroid) coils
Molten
Melt
X
Bottom
Refractory Ring
Material and
Ladle Wall
X
Top View of Furnace Lid

31. MS 3005 DESIGN PROJECT
Discussions - Electromagnetic Stirring
Proposed solution 1: Installation of stirrers at top of furnace
Predicted Flow lines
Electromagnetic transducer

32. MS 3005 DESIGN PROJECT
Discussions - Electromagnetic Stirring
Proposed solution 1: Installation of stirrers at top of furnace
Verdict: Unsuitable
 Inefficient Stirring pattern generated
 Inadequate Stirring strength
 Stirring strength will have to rely on a single electrode
 Distance of electrode to melt
Solution: Installation of stirrers at side of furnace

33. MS 3005 DESIGN PROJECT
Discussions - Electromagnetic Stirring
Proposed solution 2: Installation of stirrers at side of furnace
Slag
Molten Metal
H
ν
F
Electromagnetic
transducers Electromagnetic
transducers

34. MS 3005 DESIGN PROJECT
Discussions - Electromagnetic Stirring
Proposed solution 2: Installation of stirrers at side of furnace
 Final Solution
 Installation of transducer at side of furnace
Summary
 Placement and number of magnetic stirrers
 Ability to control flow strength
 Predetermined stirring patterns for optimum performance
 Workable idea

35. MS 3005 DESIGN PROJECT
Recommendations
 Installation of Heat Exchanger system
 Improvements in Refractory Material
 Refractory Cooling System

36. MS 3005 DESIGN PROJECT
Review
 Summary of the current electric furnace operation present
 Literature review
 Why stainless steel is chosen
 Materials selection of the roof for the EAF (group design)
 Ellingham diagram and Vacuum Oxidation Decarburization
 Design of the Furnace in incorporating an extensible roof with vacuum
 Design of the Furnace by implementing and installing magnetic stirrers
– side of furnace versus top of furnace
 Recommendations for future work
 Last but not least . . .

37. MS 3005 DESIGN PROJECT
Questions & Answers
 “Now… who ever said that steel making
was a process that is hard to
understand...”
 “perhaps if your presenter was that
informative, more students will be
interested to venture into the steelmaking
industry!”
 Thank you. . .
 Questions and Answers