6.1

Question 1

What is a ferrous metal.

Answer 1

Any alloy containing iron as its main ingredient

Question 2

What is tensile strength

Answer 2

Ability to withstand stress under tension.

Question 3

What is compressive strength.

Answer 3

Ability of a metal to withstand pressing.

Question 4

What is shear strength

Answer 4

Ability to withstand stress acting Coplanar

Question 5

What is torsional strength

Answer 5

Ability to resist rotational shear

Question 6

What is flexural strength

Answer 6

Bending strength

Question 7

Fatigue / Endurance strength

Answer 7

Ability to resist repeated loading.

Question 8

Impact strength

Answer 8

Ability to resist shock.

Question 9

What is hardness

Answer 9

Refers to a metal ability to resist cutting , penetrating , or abrasion

Question 10

What is malleability

Answer 10

Can be bent , formed , or shaped without cracking or breaking.

Question 11

What is ductility

Answer 11

Ability to be drawn into wire stock.

Resistance to failure under shock loads.

Question 12

Brittleness

Answer 12

Tenancy to break or shatter under stress.

Question 13

What is conductivity.

Answer 13

Cary heat and electricity.

Question 14

What is toughness

Answer 14

Resist tearing or breakage when bent or shattered.

Question 15

What is fusibility

Answer 15

Ability to be joined by heating + melting.

Question 16

Effect of sulphur in steel

Answer 16

Causes steel to be brittle
Removed in the refining process

Question 17

Effected of silicon in steel

Answer 17

Acts as a hardener

When used in small quantities, improves ductility.

In low carbon steels it can be detrimental to the surface finish.

Question 18

Effect of Phosphorus in steel.

Answer 18

Raises yield strength.

Improves low carbon carbon steels resistance to amospheric corrosion

Question 19

What effect does nickel have on steel

Answer 19

Adds strength + hardness
Increases yield strength

Question 20

What effect does chromium have on steel?

Answer 20

Increase strength and hardness
Increases its wear and corrosion resistance.

Question 21

What effect does molybdenum have on steel

Answer 21

Increases impact strength and elastic limit

Extremely wear resistant and has lots of fatigue strength

Most common type used in aircraft airframes.

Question 22

What is the effect of vanadium on steel

Answer 22

When combined with chromium, vanadium produces a strong tough ductile steel alloy

Used in wrenches + ball bearings.

Question 23

Effect of tungsten on steel

Answer 23

Makes a steel with a high melting point.

Question 24

What is stainless steel

Answer 24

Used in firewalls

Contains large amounts of chromium and nickel

Divided into 3 subcategory’s based on chemical structure:
Austenitic
Martensitic
Ferretic

Question 25

Austenitic stainless steel

Answer 25

Referred to as 200 and 300 series stainless steel. Non-magnetic.

Question 26

Ferritic stainless steel

Answer 26

400 series Chromium as a major alloying element Magnetic

Question 27

Martensitic stainless steel

Answer 27

400 series Magnetic Lots of chromium- 11-17 % Corrosion resistant .

Question 28

Effect of carbon mixed with iron

Answer 28

Creates steel Allows steel to be heat treated to obtain varying levels of hardness strength and toughness. Higher content decreases malleability , weld ability

Question 29

What does the first digit indicate on SAE classification of steel

Answer 29

The principal alloying element.

Question 30

What do the last digits of SAE classification of steel indicate?

Answer 30

Percentage level of carbon

Question 31

What is ferrite

Answer 31

Pure iron Body centred cubic (BCC) crystal Absorb up to 0.2% carbon

Question 32

What is astenite?

Answer 32

The preferred type of steel in aviation Face centred cubic (FCC) lattice Absorb up to 2.0% of carbon

Question 33

What is cementite?

Answer 33

AKA iron carbide Very hard and brittle Below UTC

Question 34

What is pearlite

Answer 34

Mix of cementite and ferrite (I think)

Question 35

What are the important factors in the heat treatment of steel?

Answer 35

Temperature % carbon Time taken to cool

Question 36

What is martensite

Answer 36

Very similar structure to austenite but occurs due to rapid cooling of austenite and is very. Brittle

Question 37

What type of crystal is martensite?

Answer 37

Body entered tetragonal

Question 38

What is annealing of steel

Answer 38

Heating the steel around 10 degrees above its upper critical limit and holding it there (soaking) Softens the steel and relieves internal stresses Can’t be used on aircraft

Question 39

What is normalising of steel

Answer 39

Heat 38 degrees above UCL and soaking it for a prescribed time. Then allowing it to cool at room temp Relieves internal stresses Important for welded components

Question 40

What is tempering of steel

Answer 40

Method used to decrease the hardness therefore increasing ductility and toughness of quenched steel and reducing its brittleness. Accurate temperature control is needed

Question 41

Examples of ways of monitoring temperature

Answer 41

Pyrometer Thermocouples Paint or crayons Colour

Question 42

What is case hardening of steel

Answer 42

Two types: carburising and nitriding Hardens outer surface but keeps the inner surface tough

Question 43

What is direct hardening

Answer 43

Flame or induction hardening Flame hardening: Oxy-acetylene torch Induction hardening: Heats entire circumference simultaneously

Question 44

What type of metals are the FCC, BCC and the BCT

Answer 44

FCC = austenite BCC = ferrite BCT = martensite

Question 45

What is the critical temperature