Engineering Materials

Question 1

What are the 2 alloys of iron?

Answer 1

Steel and Cast Iron

Question 2

What are the 2 types of steel?

Answer 2

Plain Carbon Steel and Alloy Steel

Question 3

What is the range of carbon content in steel?

Answer 3

0-2%

Question 4

What is the range of carbon content in plain carbon steel?

Answer 4

0.03%-1.2%

Question 5

What is the range of carbon content in cast iron?

Answer 5

2%-4%

Question 6

What is the structure of pure iron at room temperature?

Answer 6

BCC

Question 7

What is pure iron at room temperature called?

Answer 7

Ferrite

Question 8

Characteristics of Ferrite

Answer 8

Soft and Ductile

Question 9

How much carbon is in Ferrite?

Answer 9

0%-0.04% Carbon

Question 10

What is the name of a grain that forms when steel is at red heat?

Answer 10

Austenite

Question 11

How much carbon is in Austenite?

Answer 11

0%-2% Carbon

Question 12

What is the structure of Austenite

Answer 12

FCC

Question 13

Characteristics of Austenite

Answer 13

Soft and Ductile

Question 14

Which is Denser? FCC or BCC?

Answer 14

FCC

Question 15

When Austenite (steel at red heat) cools, what does it change into?

Answer 15

Ferrite and Cementite

Question 16

Chemical Formula of Cementite

Answer 16

Fe₃C

Question 17

Characteristics of Cementite

Answer 17

Hard and Brittle

Question 18

What is layers of Ferrite and Cementite called?

Answer 18

Pearlite

Question 19

Characteristics of Pearlite

Answer 19

Hard and Strong

Question 20

Carbon % in Low Carbon Steel

Answer 20

0% - 0.15%

Question 21

Carbon % in Mild Steel

Answer 21

0.15% - 0.3%

Question 22

Carbon % in Medium Carbon Steel

Answer 22

0.3% - 0.6%

Question 23

Carbon % in Ultra High Carbon Steel

Answer 23

1% - 2%

Question 24

3 examples of where Low Carbon Steel is used

Answer 24

Fence, Car bodies, Chains

Question 25

3 examples where Mild Steel is used

Answer 25

Structural steels such as ...

Question 26

3 examples where Medium Carbon Steel is used

Answer 26

Gears, Axles, Rails

Question 27

3 examples where High Carbon Steel is Used

Answer 27

Spanners, Hammers, Screwdrivers

Question 28

3 examples where Ultra-High Carbon Steel is used

Answer 28

Knives, Drills, Taps

Question 29

What does Nickel do?

Answer 29

Increases toughness and fatigue resistance

Question 30

What does Chromium do?

Answer 30

Gives good wear resistance

Question 31

What does Manganese and Silicon do?

Answer 31

Used for Strengthening and Toughening

Question 32

What does Molybdenum do?

Answer 32

Increases high temperature hardness and strength

Question 33

What does Tungsten do?

Answer 33

Good high temperature wear resistance

Question 34

What does Vanadium do?

Answer 34

High toughness

Question 35

Uses of Nickel

Answer 35

High strength structural work

Question 36

Uses of Chromium

Answer 36

Ball and roller bearings

Question 37

Used of Manganese and Silicon

Answer 37

Gears and Axles

Question 38

Uses of Molybdenum

Answer 38

Aircraft Structures

Question 39

Uses of Tungsten

Answer 39

Tool Steels

Question 40

Uses of Vanadium

Answer 40

Springs and Crankshafts

Question 41

3 Reasons for Heat Treatment

Answer 41

1. Relief of Internal Stress 2. Produce a Uniform Grain Structure 3. Soften the metal for further working or machining

Question 42

Explain the Process of Full Annealing

Answer 42

Heat the steel to red heat. Leave it until all grains have changed to austenite then cool very slowly in a furnace

Question 43

Explain the Process of Normalising

Answer 43

Heat the steel above red heat. Cool in still air to room temperature.

Question 44

Explain the Process of Hardening

Answer 44

Heat steel above red heat and cool quickly (quench). The FCC does not have enough time to become a BCC so becomes a BCT. This material is called Martensite.

Question 45

Explain the Process of Tempering

Answer 45

Heat HARDENED steel to temperature below critical temperature (723°C) to remove internal stress and then cool.

Question 46

What is precipitation hardening?

Question 47

How is natural aging done?

Answer 47

Harden the alloys at room temperature

Question 48

How is artificial aging done?

Answer 48

Using heat to speed up precipitation