Chapter 12 - Ferrous Alloys

Question 1

how does Boron effect Steel?

Answer 1

Improves hardness without loss of machinability & formability

Question 2

how does Calcium effect Steel?

Answer 2

Deoxidizes steels, improves toughness, and may improve formability and machinability

Question 3

how does Carbon effect Steel?

Answer 3

improves hardenability, strength, hardness, and wear resistance; it
reduces ductility, weldability, and toughness

Question 4

How does Cerium effect steel?

Answer 4

controls the shape of inclusions and improves toughness in high-strength
low alloy steels; it deoxidizes steels

Question 5

How does Chromium effect steel?

Answer 5

improves toughness, hardenability, wear and corrosion resistance, and
high-temperature strength; it increases the depth of the hardness penetration
resulting from heat treatment by promoting carburization

Question 6

How does Cobalt effect steel?

Answer 6

improves strength and hardness at elevated temperatures

Question 7

How does Copper effect steel?

Answer 7

improves resistance to atmospheric corrosion and, to a lesser extent,
increases strength with little loss in ductility; it adversely affects the hot-working
characteristics and surface quality

Question 8

How does Lead effect steel?

Answer 8

improves machinability; it causes liquid-metal embrittlement

Question 9

How does Magnesium effect steel?

Answer 9

Same as cerium

Question 10

How does Manganese effect steel?

Answer 10

improves hardenability, strength, abrasion resistance, and
machinability; it deoxidizes the molten steel, reduce shot shortness, and decreases
weldability

Question 11

How does Molybdenum effect steel?

Answer 11

improves hardenability, wear resistance, toughness, elevatedtemperature
strength, creep resistance, and hardness; it minimizes temper
embrittlement

Question 12

How does Nickel effect steel?

Answer 12

improves strength, toughness, and corrosion resistance; it improves
hardenability

Question 13

How does Niobium efect steel?

Answer 13

imparts fineness of grain size and improves strength and

impact toughness; it lowers transition temperature and may decrease hardenability

Question 14

How does Phosphorus effect steel?

Answer 14

imparts fineness of grain size and improves strength and
improves strength, hardenability, corrosion resistance, and
machinability; it severely reduces ductility and toughness

Question 15

How does Selenium effect steel?

Answer 15

Improves machinability

Question 16

How does silicon effect steel?

Answer 16

improves strength, hardness, corrosion resistance, and electrical
conductivity; it decreases magnetic-hysteresis loss, machinability, and cold
formability

Question 17

How does Sulphur effect steel?

Answer 17

Improves machinability when combined with manganese; it lowers impact
strength and ductility and impairs surface quality and weldability

Question 18

How does Tantalum effect steel?

Answer 18

Has effects similar to those of niobium

Question 19

How does Telletium effect steel?

Answer 19

improves machinability, formability, and toughness

Question 20

How does Titanium effect steel?

Answer 20

improves hardenability; it deoxidizes steels

Question 21

How does Tungsten effect steel?

Answer 21

has the same effects as cobalt

Question 22

How does Vanadium effect steel?

Answer 22

improves strength, toughness, abrasion resistance, and hardness at
elevated temperatures; it inhibits grain growth during heat treatment

Question 23

How does Zirconium effect steel?

Answer 23

Same as Cerium

Question 24

What is a low alloy steel?

Answer 24

Alloyed steel when less than 5% of weight is alloying elements

Question 25

What are the 3 common low alloy steels?

Answer 25

Low, Medium & High Carbon steels

Question 26

What are the characteristics of Low carbon Steels?

Answer 26

- 0.1-0.25% Carbon - High Formability - High ductility - Low strength - Good weldability - Can't be hardened by heat treatment - Hardened by cold working

Question 27

What are the characteristics of Medium carbon Steels?

Answer 27

- 0.25 - 0.55% Carbon - Good combination of strength and ductility - Strengthened by heat treatment - Weldable

Question 28

Advantages of low alloy steels?

Answer 28

low cost, high weldability & most used

Question 29

Disadvantages of low alloy steels?

Answer 29

Relatively low strength, low hardenability & low corrosion resistance

Question 30

What are high alloy steels?

Answer 30

Alloyed steel when more than 5% of weight is alloying elements

Question 31

Name 2 common high alloy steels?

Answer 31

Stainless steel | tool steels

Question 32

What are stainless steels characteristics?

Answer 32

- Corrosion resistant - High Strength - Ductility - Chromium content

Question 33

What are the main alloying elements in tool steel?

Answer 33

Chromium, Cobalt and Manganese

Question 34

How are tool steels classified?

Answer 34

By: - quenching methods (Air, oil or water hardening) - Carbon & Alloy content

Question 35

What is Cast iron?

Answer 35

Iron with 1.7 to 4.5 wt% carbon and 0.5 to 3 wt% | silicon

Question 36

What are the characteristics of cast iron?

Answer 36

Good castsability & low cost material

Question 37

What are the advantages of cast iron?

Answer 37

- good castability - antivibration properties - low stress concentration

Question 38

What are the disadvantages of cast iron?

Answer 38

- high brittleness - non machinable - cold brittleness

Question 39

What is grey cast iron?

Answer 39

Flake graphite in a matrix of pearlite, ferrite or martensite

Question 40

How does grey cast iron form?

Answer 40

when: • Cooling is slow, as in heavy sections • High silicon or carbon

Question 41

What are the properties of grey cast iron?

Answer 41

* Machinability is excellent * Ductility is low (0.6%), impact resistance low * Damping capacity high * Thermal conductivity high * Dry and normal wear properties excellent

Question 42

What is white cast iron?

Answer 42

- It is a particular variety of cast iron which shows white fractures - The white colour is due to the fact that the carbon is in the form of carbides known as cementite

Question 43

What are white cast irons characteristics?

Answer 43

– It has a high tensile strength and a low compressive strength – Extremely hard, not machinable – Resistance to sharp objects and cracks

Question 44

What is malleable cast iron?

Answer 44

– Malleable cast iron is obtained from white | cast iron by suitable heat treatment

Question 45

What are malleable cast irons characteristics?

Answer 45

``` It is ductile and may be bent without breaking or fracturing the section – It is used for making machine parts for which steel forging would be too expensive ```