The document discusses different types of metals and materials used in engineering, including ferrous and non-ferrous metals. It describes various steel alloys such as carbon steels, alloy steels, and stainless steels. Carbon steels are classified based on their carbon content as low, medium, or high carbon steels. Alloying elements are added to steels to improve properties like strength, corrosion resistance, and workability. Stainless steels contain chromium to increase corrosion resistance and are divided into ferritic, martensitic, austenitic, and duplex classes. The document also reviews steel designation systems used in standards like AISI, ASTM, and DIN.

1. Feroze Ali Khan
Zahid Majeed

2. Types of Materials
Metals
Non - metals
Ferrous
Non- ferrous
Carbon Steels
Alloy Steels
Cast Iron
Non - metals
Non- ferrous

3. Ferrous Metals
▀ Original definition
 Iron contents greater than 50%
▀ Revised definition(1993)
 Material which contains by mass more Iron than any other single
element
Cr : 26 max.
Ni : 22 max.
Mn : 02 max.
Si : 1.5 max.
Total : 51.5 max.
SS 310

4. Pure Iron
▀ Limited usefulness for engineering applications
▀ Low strength
▀ Poor resistance to corrosion

5. Hardness
▀ Resistance of a surface to being indented by an indenter under
standard conditions
▀ Rockwell or Brinell hardness number

6. Hardenability
▀ Ability of a steel to harden, i.e. to form martensite to depth
▀ Steel with high hardenability have a low critical cooling rate , i.e.
having ability to form martensite at low cooling rates
 Low carbon steels
 High carbon steels
 Alloy Steels
Hardenability
Hardenability
Hardenability
Hardness Brittlenes
Strength Toughness

7. Alloying elements
▀ The most important and most frequently applied alloying elements of
steel are:
 Manganese (Mn),
 Nickel (Ni),
 Chromium (Cr),
 Tungsten (W),
 Vanadium (V),
 Molybdenum (Mo),
 Titanium (Ti),
 Niobium (Nb)
 Boron (B).

8. Aim of Alloying elements
▀ Improve mechanical properties (e.g. strength, ductility, toughness)
▀ Increase resistance to corrosion (chemical resistance)
▀ Improve certain physical properties (e.g. magnetic, electrical
properties)
▀ Improve complex properties of technological workability (e.g.
formability, weldability, machinability)

9. Effects of Carbon
Hardness Strength Ductility Weldability
Carbon

10. Carbon Steels
2.0% C
1.65%
Mn
0.6%
Si
0.6%
Cu
P, S
No alloying element
Cr, Co, Mo, Nb, Ni, Ti, V, W Zr

11. Carbon Steels Classification
▀ On the basis of Carbon content
 Low carbon steels (C = 0.1 to 0.3%)
 Medium carbon steels (C =0.3% to 0.6%)
 High carbon steels (C =0.6% to 2.0 %)
▀ On the basis of deoxidation process
 Rimmed carbon steel
 Semi-killed carbon steel
 Capped carbon steel
 Fully-killed carbon steel

12. Low Carbon Steels
▀ Composition:
 Contains 0.10 to 0.30% Carbon
▀ Properties:
 Good formability and weldability
 Grades having 0.1 to 0.30% C are heat treatable
 Low strength, low cost
▀ Applications:
 Low, medium and high pressure steam/condensate lines
 Cooling water, instrument air, fuel gas, natural gas lines
 Liquid Ammonia lines

13. Medium Carbon Steels
▀ Composition:
 Contains 0.30 to 0.60% Carbon
▀ Properties:
 Good toughness and ductility
 Relatively good strength
 Heat treatable
▀ Applications:
 Manufacturing Of Gears, Crankshaft Etc

14. High Carbon Steels
▀ Composition:
 Contains 0.6 to 2.0% Carbon
▀ Properties:
 High strength, hardness and wear resistance
 Moderate ductility
▀ Applications:
 Springs, high strength wires
 Rolling mills, screw drivers, hammers, wrenches, band saws

15. Fully-killed Carbon Steels
▀ Deoxidation extent:
 Fully-deoxidized
 No carbon monoxide or any other gas evolution during ingot
solidification
 Homogeneous structure in the final product
▀ Applications:
 Piping, valves and vessels for low temperature liquid ammonia

16. Alloy Steels
Carbon Steels
Alloying
Element
Alloying element
Cr, Co, Mo, Nb, Ni, Ti, V, W Zr

17. Classification of Alloy Steels
 Low alloy steels (alloying elements < 8%)
 High alloy steels (alloying elements > 8%)
GENERAL USES
- Pressure vessel, piping at high temperature
COMPOSITION
- Cr upto 2.25% and Mo up to 1.25%
MECHANICAL PROPERTIES
- High strength at temperatures up to 650 0c
- Difficult welding as heat treatment is involved
ALLOYING EFFECT
- Cr increases corrosion resistance
- Mo Adds Elevated Temperature Strength
Cr – Mo STEELS
- Piping, valves and vessels for very high pressure steam (KS)

18. Stainless Steel
Carbon Steel
Cr

19. Stainless Steel
Chromium
Oxygen

20. Effect of Chromium

21. Sensitization
About 800°C
Chromium
Carbon

22. Sensitization
About 800°C
Chromium
Carbon

23. Sensitization
▀ At elevated temperatures, chromium reacts with carbon and
precipitates as chromium carbide at the grain boundaries
▀ Methods of avoiding sensitization:
 Use of Stainless Steels with extra low levels of carbon
 Use of Titanium or niobium at approx. 5-6 time the interstitial content

24. AUSTENITIC STAINLESS STEEL
UN-STABILIZED GRADE
- SS 304
- SS 316
- 25 Cr – 22 Ni – 2 Mo
- 316L + G510
STABILIZED GRADE
- SS 321
- SS 347
Cannot Be Used for High
Temperature
Can Be Used for High
Temperature

25. Schaeffler diagram
where
▀ Nieq = %Ni+30%C+
30%N+0.5%Mn
▀ Creq = %Cr+%Mo+
1.5%Si+0.5%Nb

26. Classification of Stainless Steel
Stainless
Steel
Ferritic Stainless Steels
Martensitic Stainless Steels
Austenitic Stainless Steels
Duplex Stainless Steels

27. Ferritic Stainless Steels
COMPOSITION
MECHANICAL PROPERTIES
GENERAL USES
- POOR WELDABILITY
- MODERATE TO GOOD CORROSION RESISTANT
- DOMESTIC EQUIPMENTS
- CANNOT BE HARDENED BY HEAT TREATMENT
C .3%
Cr UP TO 30%
Ni 0%

28. Martensitic Stainless Steels
COMPOSITION
MECHANICAL PROPERTIES
GENERAL USES
- POOR WELDABILITY
- MODERATE CORROSION RESISTANT
- SHAFTS, SURGICAL INSTRUMENTS, FASTENERS
- CAN BE HARDENED BY HEAT TREATMENT
C
1.2%
Cr UP TO 17%
Ni 0%
- PUMP SHAFTS, IMPELLERS FOR CORROSIVE SERVICE

29. Austenitic Stainless Steels
COMPOSITION
MECHANICAL PROPERTIES
GENERAL USES
- GOOD WELDABILITY
- EXCELLENT CORROSION RESISTANT
- FOOD PROCESSING, CORROSIVE SERVICES e.g. UREA, ACID etc.
- CAN BE USED AT LOW AND HIGH TEMPERATURE (UP TO 900 0C)
Ni UP TO 30%
Cr UP TO 30%
C 0.3%
- CANNOT BE HARDENED BY HEAT TREATMENT
- ALL PRESSURE UREA SERVICE AND UREA FLUSHING CIRCUIT
- PIPING, VALVES AND VESSELS FOR
- MDEA, PROCESS GAS, DEMIN WATER

30. Duplex Stainless Steels
COMPOSITION
MECHANICAL PROPERTIES
GENERAL USES
- GOOD STRENGTH : GREATER THAN AUSTENITIC AND OTHER GRADES
- GOOD CORROSION RESISTANCE
- OFF-SHORE APPLICATIONS, HIGH PRESSURE UREA
- GOOD WELDABILITY
C
.3%
Cr UP TO 30%
Ni UP TO 8%
- UREA REACTOR (STAMI CARBON PLANTS)
- STEMS FOR HIGH PRESSURE UREA VALVES

31. Stainless Steel Family
SS-304
SS-316
SS-317
Add Mo for pitting
resistance
SS-304L
SS-316L
SS-317L
Lower C to
reduce
sensitization
SS-321
SS-347
Add Ti to reduce
sensitization
Add Nb + Ta to
reduce sensitization
SS-309
Add Cr and Ni for
strength and oxidation
resistance
NiCrFe Alloy
Add Ni for corrosion
resistance in high temperature
environments
SS-310 SS-314
SS-410 SS-420
Lower Cr with
no Ni addition
Add Mo for pitting
resistance

32. Materials Designation Systems
- American Society for Testing Materials
ASTM
- American Iron and Steel Institute
AISI
- Society of Automotive Engineers
SAE
- Unified Numbering System
UNS
- German Standards
DIN
- British Standards
BS
- Japanese Standards
JS

33. AISI/SAE – Designation System
X X X X
Class of Steel
1 Carbon Steels
2 Nickel steels
3 Nickel-chromium steels
4 Molybdenum steels
5 Chromium steels
6 Chromium-vanadium steels
7 Tungsten-chromium steels
9 Silicon-manganese steels
modification of the steel
0 Plain carbon, non-modified
1 Resulfurized
2 Resulfurized and rephosphorized
5 Non-resulfurized, Mn over 1.0%
carbon concentration in
0.01%
1 0.01% Carbon
SAE
steel making technology
A Alloy, basic open hearth
B Carbon, acid Bessemer
C Carbon, basic open hearth
D Carbon, acid open hearth
E Electric furnace

34. Alloy Steels – Four Digit Classification
4 1 4 0
Class of Alloy Steel
1 Carbon Steel
2 Nickel steels
3 Nickel-chromium steels
4 Molybdenum steels
5 Chromium steels
6 Chromium-vanadium steels
7 Tungsten-chromium steels
9 Silicon-manganese steels
concentration of the
major element in
percents
1 1%
carbon concentration
in 0.01%
40 0.4% Carbon
SAE

35. Stainless Steels – Three Digit Classification
STAINLESS STEEL
3 16
No Specific Interpretation
MATERIAL TYPE
Z
Element addition
- Austenitic Stainless Steel
2
- Austenitic Stainless Steel
3
- Low Carbon (<0.03%)
L
- High Carbon Contents
H
- Added Nitrogen
N
- Added Copper
Cu
- Martensitic & Ferritic
4

36. ASTM – Designation System
516 M -
ASTM 90 Grade 70
Ferrous Metal
Sequential Number
Metric System Year of revision
Chemical
Composition
Min Tensile Strength
(ksi)

37. ASTM – Designation System
106 -
ASTM 91 Grade B
Ferrous Metal
Sequential
Number
Year of revision
Chemical
Composition
Min Tensile Strength
(ksi)

38. THANK YOU