Crystal Structure and Plain Carbon Steel

Question 1

Equiaxed grains metal properties

Answer 1

Ductile, Softer

Question 2

After cold working, describe what are the grains like and list properties of the metals.

Answer 2

Distorted Grains,
Properties: Stronger, Harder,
more brittle and less ductile,
higher internal stress

Question 3

BCC metals

Answer 3

alpha-iron, tungsten

Question 4

FCC metals

Answer 4

Aluiminium, copper, gamma-iron

Question 5

HCP/CPH metals

Answer 5

Magnesium, Zinc, Titanium at low temp.

Question 6

What are the 2 elements harmful to plain carbon steels?

Answer 6

Sulphur and phosphorus

Question 7

Allotropic element

Answer 7

Iron, can exist in more than one physical form (BCC, FCC)

Question 8

2 structure name when carbon dissolves in FCC and BCC iron

Answer 8

FCC iron: Austenite

BCC iron: Ferrite

Question 9

What are the properties of austenite and its crystal structure?

Answer 9

Properties: soft, non-magnetic and very ductile

Crystal structure: FCC

Question 10

What are the properties of ferrite and its crystal structure?

Answer 10

properties: soft, ductile and magnetic

BCC structure

Question 11

Properties of cementite

Answer 11

very hard and brittle

Question 12

properties of pearlite

Answer 12

stronger and harder than ferrite but tougher than cementite

Question 13

Maximum carbon austenite can dissolve is

Answer 13

0.8%

Question 14

An increase in carbon content in plain carbon steel will result in an increase in

Answer 14

tensile strength (up to 0.8%C)
hardness
wear resistance

Question 15

An increase in carbon content in plain carbon steel will have a decrease in

Answer 15

ductility (evidence from % elongation)
toughness
machinability
weldability
corrosion resistance

Question 16

% carbon of dead mild steel, mild steel, medium carbon steel, high carbon steel, carbon tool steel

Answer 16

Dead mild: 0.05 - 0.15%
Mild steel: 0.15 - 0.3%
Medium carbon: 0.3 - 0.6%
High carbon: 0.6 - 0.8%
Carbon tool: 0.8 - 1.4%

Question 17

Application of dead mild steel and mild steel

Answer 17

dead mild: car body, tubes, chains

mild steel: ship plate, steel sections for constructions

Question 18

application of medium carbon steel, high carbon steel and carbon tool steel

Answer 18

medium carbon: gears, crankshafts, axle
high carbon: screw drivers, hammers, wrenches
carbon tool steel: chisels, files, axes, drills