Ferrous Metals and Alloys

Question 1

What is Wrought Iron?

Answer 1

Wrought iron is an iron alloy with very low carbon content of 0.02% - 0.03% and has fibrous inclusions, known
as slag.

Question 2

List at least 4 uses of Wrought Iron.

Answer 2

Items produced from
wrought iron included:
rivets, nails, wire, chains, railway couplings, nuts, bolts, horseshoes,
handrails and ornamental ironwork.

Question 3

What are the properties of Wrought Iron, HENCE, Which purpose is it used for?

Answer 3

Wrought iron is tough, malleable, ductile and easily welded. Used when Toughness and resistance to shock is required at a low cost.

Question 4

At what temperatures does Iron become a Body-Centered and a Face-Centered Cubic lattice?

Answer 4

BCC (alpha): Room Temperature - 910°
FCC (gamma): 911° - 1399°
BCC (delta): 1400° -1538°
Melting point onwards

Question 5

When Carbon% increases in Ferrite for Pearlite, it will increase and decrease which Mechanical properties?

Answer 5

✅ Pearlite %, Tensile Strength, and Hardness
❌ Toughness, ductility, Elongation %, Corrosion resistance, Machinability and Weldability.

Question 6

List the advantages of alloy steels

Answer 6

• Greater Hardenability
• Greater strength at high temperatures
• Less grain growth
• Less distortion and cracks
• Higher elastic ratio and fatigue strength.
• Greater stress relief at a given hardness

Question 7

List the Disadvantages of Alloy Steel

Answer 7

• Special handling
• Higher cost
• Tendency towards auestenitic retention
• Temper brittleness at certain grades

Question 8

What are the 5 types of alloy steel?

Answer 8

Constructional Steels, Corrosion- resistant Steels, Wear-resistant Steels, Heat-resistant steels, Tool & die steels

Question 9

What are the two types of Malleable Irons?

Answer 9

Whiteheart and Blackheart

Question 10

How are the objectives of annealing for both Whiteheart and Blackheart done?

Answer 10

Whiteheart: Mainly decarburisation but some graphitisation.
Blackheart: Graphitisation.

Question 11

Describe the form of white cast iron

Answer 11

It is combined with iron to form cementite.
If the carbon is combined as cementite, the iron will be hard, brittle and unmachinable. A fresh
fractured surface appears bright and silvery and this is termed as white cast iron.

Question 12

Describe the form of grey cast iron

Answer 12

It is free carbon or graphite.
If the carbon is free in the form of graphite, the iron will be relatively soft and machinable and
will give a greyish fracture, hence the name grey cast iron.