6.1

Question 1

what is a ferrous material

Answer 1

alloy containing iron as its main ingredient and is magnetic

Question 2

why can pure iron not be used in aviation

Answer 2

It is ductile and soft and reacts with oxygen

Question 3

what else is needed to make iron from iron ore

Answer 3

coke and limestone with hot air

Question 4

why is limestone used to make iron

Answer 4

to remove impurities

Question 5

what is remelted to make steel

Answer 5

cast iron / pig iron

Question 6

what needs to be removed from cast iron to make steel and how does it happen

Answer 6

the carbon needs to be removed and it is done by forcing oxygen through it

Question 7

what percent is low carbon steel

Answer 7

0.1-0.3%

Question 8

what percent is medium carbon steel

Answer 8

0.3-0.5%

Question 9

what percent is high carbon steel

Answer 9

0.5-1.05%

Question 10

what does tensile strength withstand

Answer 10

tension

Question 11

what does compressive strength withstand

Answer 11

pressing/ squeezing

Question 12

what does shear strength withstand

Answer 12

stress coplanar to cross section

Question 13

what does torsional strength withstand

Answer 13

rotational shear

Question 14

what does flexural strength withstand

Answer 14

bending

Question 15

what does fatigue/ endurance strength withstand

Answer 15

repeated loading

Question 16

what does impact strength withstand

Answer 16

shock

Question 17

what does hardness resist

Answer 17

cutting, penetration or abrasion

Question 18

what does toughness resist

Answer 18

tearing/ breaking when bent/ stretched

Question 19

what is the most common alloying agent

Answer 19

carbon

Question 20

what alloying agent causes steel to be brittle and must be removed when refining

Answer 20

sulphur

Question 21

what alloying agent acts as a hardener and in small quantities improves ductility

Answer 21

silicon

Question 22

what alloying agent raises yield strength and improves low carbon resistance to atmospheric corrosion

Answer 22

phosphorous

Question 23

what alloying agent adds strength and hardness to steel and increases yield strength

Answer 23

nickel

Question 24

what alloying agent increases strength and hardness and improves wear and corrosion resistance

Answer 24

chromium

Question 25

what alloying agent is most widely used for aircraft structure and reduces grain size

Answer 25

molybdenum

Question 26

what alloying agent is normally combined with chromium to make ball bearing

Answer 26

vanadium

Question 27

what alloying agent has an extremely high melting point

Answer 27

tungsten

Question 28

what is stainless steel and what are the main alloying agents

Answer 28

classification of corrosion resistant steel mainly made of chromium and nickel

Question 29

what are the 3 types of stainless steel

Answer 29

austenitic, ferritic, martensitic

Question 30

what is the first digit in the classification of steels

Answer 30

principal alloying element

Question 31

what are the last 2 digits in the classification of steels

Answer 31

average carbon percent

Question 32

what is heat treating

Answer 32

process of heating up and cooling down carbon steel to change physical and mechanical properties

Question 33

what is an eutectoid

Answer 33

a metal that can exist in more than one different form at the same temperature

Question 34

what is the critical temperature

Answer 34

temperature when a phase change happens during heating or cooling

Question 35

what is quenching

Answer 35

rapidly cooling a metal after heating

Question 36

what is annealing

Answer 36

heat the metal 10C above critical temperature and heat soak it at that temperature

Question 37

what does annealing do

Answer 37

softens steel and releaves internal stress

Question 38

what is normalising

Answer 38

heating 38C above critical temperature and heat soaking for a prescribed time then at room temperature

Question 39

what does normalising do

Answer 39

relieves internal stresses

Question 40

what does tempering do

Answer 40

decreases hardness and increases ductility

Question 41

what does case hardening do to low carbon steels

Answer 41

creates a hard durable surface

Question 42

what does case hardening do to high carbon steels

Answer 42

makes the core very brittle

Question 43

what are the 2 methods of case hardening

Answer 43

carburising and nitriding

Question 44

what is direct hardening

Answer 44

surface is heated very rapidly to a high temperature by flame or induction hardening and then cooled very quickly this creates a 'case' of martensite on the surface

Question 45

what is the difference between flame and induction hardening

Answer 45

flame hardening only heats up a part of the surface at at time whereas induction heats the entire surface at once

Question 46

what is malleability

Answer 46

ability to be bent, formed or shaped without cracking or breaking

Question 47

what is ductility

Answer 47

ability of metal to be drawn into wire, extrusions or rods

Question 48

what is brittleness

Answer 48

material's tendency to break or shatter when exposed to stress

Question 49

what are the characteristics of austenitic stainless steel

Answer 49

non magnetic in annealed condition but some can be slightly magnetic after cold working

Question 50

what are the characteristics of ferritic stainless steel

Answer 50

chromium is major alloying element, magnetic and generally have good ductility

Question 51

what are the characteristics of martensitic stainless steel

Answer 51

good combination of corrosion resistance and superior mechanical properties they are magnetic

Question 52

is steel an eutectoid

Answer 52

yes because it can be in different forms at the same temperature

Question 53

what are the 4 states that steel can be in

Answer 53

ferrite, austenite, cementite, pearlite

Question 54

what are the characteristics of the ferrite form of steel

Answer 54

pure iron, is a body-centred cubic lattice

Question 55

what are the characteristics of the austenite form of steel

Answer 55

face-centred cubic form of iron

Question 56

what are the characteristics of the cementite form of steel

Answer 56

chemical compound made of iron and carbon, very hard also known as iron carbide

Question 57

what are the characteristics of the pearlite form of steel

Answer 57

2 phased lamellar structure, formed when austenite is slowly cooled below 727C

Question 58

what are the 3 different crystal structures that occur in steel due to heat treatment

Answer 58

austenite, ferrite and martensite

Question 59

what type of crystal is austenite

Answer 59

face-centred cubic

Question 60

what type of crystal is ferrite

Answer 60

body-centred cubic

Question 61

what type of crystal is martensite

Answer 61

body-centred tetragonal

Question 62

what can be used to measure a metal's temperature

Answer 62

pyrometers, thermocouple controlled ovens or by colour of metal