This document discusses different types of steels and their manufacturing processes. It begins by classifying engineering materials and discussing ferrous metals like steels. It then defines different types of steels based on carbon content, including plain carbon steels and alloy steels. The document outlines the classification of plain carbon steels and describes common manufacturing processes like Bessemer, open hearth, electric arc furnace. It also discusses stainless steels, their composition diagrams and production methods. World steel production statistics are presented along with microstructure diagrams of plain carbon steels and the iron-carbon phase diagram.

1. STEELS
Persistence is to the character of man as Carbon is to
the Steel
by Md. Asfaque
Production Engineer
SRBWIPL

2. Content Layout
 Engineering Materials and its Classification
 Steel and its types
 Classification of Plain Carbon Steels
 Manufacturing Processes of Steels
 Stainless Steel and its Composition Diagram
 How Stainless Steels are made?
 World Steel Production
 Microstructure of Plain Carbon Steel
 Iron Carbon Phase Diagram
 Conclusion video
 Cold rolled Steel Vs Hot Rolled

3. Classification of Engineering Materials
Engineering
Materials
Metals
Ferrous
Metals
Non Ferrous
Metals
Non Metals
Synthetic
materials
Natural
Materials
FerrousMetals
Steels
Cast Iron
Wrought Iron

4. STEELS and its types
 It is an alloy of Iron, Carbon and other elements with a Carbon Content upto a
maximum of 2 wt%.
Carbon Steels
Plain Carbon Steels
Are alloys with definite ranges of
Carbon and a max of 1.65 wt% Mn,
a max of 0.6 wt% Si & Cu and
maxima of Sulphur and Phosphorus
Alloy Steels
Same constituents, in addition
also contains Al, Cr, Mo, Nb, Ni,
Ti, W, Vd, Zr , etc

5. Classification of Plain Carbon Steel
PlainCarbonSteel
Dead Mild Steel
(< 0.15%)
Low Carbon Steel
(0.15%- 0.45%)
Medium Carbon Steel
(0.45%- 0.8%)
High Carbon Steel
(0.8%- 2%)

6. Manufacturing Processes of Steels
 Principal methods applied in the manufacture of Steels are:-
 Bessemer Process
 Cementation process
 Crucible Process
 Open Hearth Process (Siemens- Martin Process)
 Duplex Process
 L-D process
 Electric Process

7. Stainless Steel – It is that steel which when correctly heat treated and finished, resists
oxidation and corrosive attack from the most corrosive media.
STAINLESS STEELS
Martensitic
(11-18% Cr,
0.1-1.2% C)
Ferritic
(10-27% Cr,
0.12% C)
Austenitic
(18-35% Cr,
<35% Ni
Duplex
(21-27% Cr,
1-8% Ni,
0.05-3% Cu,
0.05-5%
Mo)
Precipitation
Hardening
(15-17% Cr,
3-5% Ni &
Cu & traces
of Al, Nb)
Source: Encyclopaedia Britannica

8. Composition Diagram of various Stainless Steels

9. How Stainless Steels are made?
Melting
• Melting iron scrap and additives in an EAF
• High power electrode heats the metals to create a molten mixture
Removing
Carbon Content
• AOD:- Injecting Argon gas reduces Carbon
• VOD:- molten steel is transferred to another chamber and Oxygen is injected into it. A vaccum then removes
the vented gases reducing Carbon Content
Tuning
• To ensure that the metal meets the requirements by balancing and
homogenisation of temperature.
Forming
• Foundry used to cast the desired shape viz, Blooms, Billets, Slabs, Tubes and Rods

10. Depending upon the grade or format,
Annealing
Cold
rolling
Hot
rolling
Quality Control
Finishing
cutting
Descaling

11. Hot rolled steel and Cold Rolled steel

12. Cold rolled Steel Vs Hot rolled Steel
 At high temperatures over 1,700˚F, which is above the
re-crystallization temperature for most steels.
 Hot worked steels are less stronger than standard cold
rolled steels.
 Less control over its final shape, making it less suitable
for precision applications.
 Lot cheaper in relative to cold rolled steel
 A scaled surface
 Slight distortions
 Railroad tracks and construction projects often use hot
rolled steel
 Cold rolled steel is essentially hot rolled steel that has
been through further processing. Once hot rolled steel
has cooled, it is then re-rolled at room temperature.
 Cold worked steels are typically harder and stronger
than standard hot rolled steels.
• Better, more finished surfaces with closer tolerances
• Smooth surfaces that are often oily to the touch
• Bars are true and square, and often have well-defined
edges and corners
• Tubes have better concentric uniformity and
straightness
• Computer-cabinet hardware; small appliance parts; and
light industrial applications such as tool boxes, shelving,
and lighting often use cold rolled steel

13. World Steel Production (2014 report)

14. Microstructure of Plain Carbon Steel
Iron (0.2% Carbon)

15. Contd…

16. Contd…

17. Invariant reactions in Iron-Carbon system
1. Peritectic Reaction
2. Eutectic Reaction
3. Eutectoid Reaction
Where,
δ= Ferrite (BCC)
γ= Austenite(FCC)
α= Low temp.
ferrite(BCC)

18. Iron-Carbon Equilibrium Diagram

19. Caption

21. Typical Bessemer Converter

22. A Cementation Furnace

23. Crucible Process

24. Open Hearth Furnace

25. Electric Arc Furnace Flow Diagram

26. Uses Linz-Donawitz Process for manufacturing Steels

27. Uses Duplex Process for manufacture of Steels