6.1 - Ferrous

Question 1

When talking about ferrous materials what is the base material?

Answer 1

Iron

Question 2

How is iron extracted from iron ore?

Answer 2

By mixing it with coke and limestone

Question 3

Why does cast iron have limited us in the aviation industry ?

Answer 3

Low strength to weight ratio and brittleness.

Question 4

What are the carbon contents of steel?

Answer 4

Low= 0.1-0.3%
Medium = 0.3-0.5%
High= 0.5-1.05%

Question 5

What % does hardness and tensile strength stop increasing at?

Answer 5

85%

Question 6

Carbon allows what in steel to occur?

Answer 6

Primary hardening and Heat treatment

Question 7

Sulphur in steel does what?

Answer 7

Decreases ductility and weld ability with increasing content. But increases machine ability.

Question 8

Manganese in steel does what?

Answer 8

Contributes to strength and hardness but not as much as carbon.

Decreases ductility and weld ability.

Question 9

Increasing manganese content in steel decreases what?

Answer 9

Ductility and weld ability

Question 10

Silicon does what to steel?

Answer 10

Acts as a deoxidiser Increases rolled strength and hardness

Question 11

Phosphorus in steel does what?

Answer 11

Increases strength, hardness and corrosion resistance.

Decreases ductility

Question 12

Nickel does what to steel?

Answer 12

Increases the harden ability and impact strength

Question 13

Molybdenum does what to steel?

Answer 13

Increases harden ability

Question 14

Titanium in steel does what?

Answer 14

Increase toughness

Question 15

SAE stands for

Answer 15

Society of automotive engineers

Question 16

ASI stands for

Answer 16

American institute of steel and iron

Question 17

Annealing does what to steel ?

Answer 17

Softens and relieve internal stresses.

Question 18

What is the process for annealing steel?

Answer 18

Heating the steel to 50 degrees F above its upper crit limit and soaking it at that temperature. Then it’s cooled slowly in a furnace or bath of hot sand.

This makes the steel very soft and ductile.

Question 19

What ferrous material can be hardened by heat treatment

Answer 19

Cast iron

Question 20

The maximum hardness of steel depends entirely on what added compound ?

Answer 20

Carbon

Question 21

Carbon steel can be softened by..?

Answer 21

Annealing

Question 22

Steel is too hard and brittle so what process decreases this so that steel can be used.

Answer 22

Tempering

Question 23

Tempering does what to steel?

Answer 23

Decreases hardness and increases toughness and ductility

Question 24

What is normalising

Answer 24

Heating steel to relieve stress caused during forging welding and machining

Question 25

What’s the normalising process?

Answer 25

Heat the steel to 100 degrees F above the upper crit limit then soak at that temp for a prescribed time then allow to cool at room temp.

Question 26

What determines the rate of quenching ?

Answer 26

The medium in which the metal is being quenched

Question 27

Ferrite is what?

Answer 27

The name given to pure iron that allow for .02% carbon to be absorbed.

Question 28

How much carbon can ferrite iron absorb?

Answer 28

0.02%

Question 29

Austerity can absorb how much carbon?

Answer 29

Up to 2%

Question 30

Cementite iron has what characteristics?

Answer 30

Hard and brittle

Question 31

Cementite is iron with what carbon content?

Answer 31

Greater than 2%

Question 32

CRES stands for

Answer 32

Corrosion resistant steel

Question 33

CRES has what characteristics (4)

Answer 33

Corrosion resistant
Strength
Toughness
Resistance to high temps

Question 34

For the CRES classification chart what steel type is represented by (200 and 300),(400)

Answer 34

200&300 is austenitic

400 is ferritic and martensitic

Question 35

Most widely used CRES is?

Answer 35

In the 300 series called 18-8

Question 36

Austenitic steels are what alloys?

Answer 36

Chromium-nickel and chromium-nickel-manganese alloys

Question 37

Austenitic can be hardened by

Answer 37

Cold working, heat treatment only anneals them.

Question 38

Austenitic steel is what In An annealed state and what can it be after being cold worked?

Answer 38

After annealing steel is non magnetic but after being cold worked it can be slightly magnetic

Question 39

Titanium helps to stop what in steel

Answer 39

Inter-granular corrosion

Question 40

Steel classification is in what format?

Answer 40

First 2 digits refer to the primary alloying element and the last 2 the percentage of carbon in the alloy,

Question 41

Chromium does what to steel?

Answer 41

Increase corrosion resistance
Oxidation resistance
Harden-ability and high temp strength.
Used in conjunction with toughening Elements like nickel.

Question 42

What is the rapid quench medium

Answer 42

Brine

Question 43

What is the slow quench material

Answer 43

Oil

Question 44

Disadvantages of Austenitic Steels

Answer 44

• difficult to cut
• greater coefficient of expansion
• not suitable in a high temp environment
• experiences techies

Question 45

What is the only form of steel that can be heat treated?

Answer 45

Martensitic

Question 46

What is hydrogen embrittlement?

Answer 46

When hydrogen reacts with carbon and forms methane.

- builds pressure underneath the grain structure

Question 47

How can you save a product that could be impacted by hydrogen embrittlement?

Answer 47

Recook for 3 hours

Question 48

What are the 3 types of carborising?

Answer 48

Pack, liquid and gas