Chapter 1, Lesson 3

Question 1

What is ductility

Answer 1

Ductility is the ability to undergo deformation due to tensile stress.
Ductility can be measured through Area Reduction and Percentage Elongation OR measured by Bend Test

Question 2

What is malleability?

Answer 2

Malleability is the ability of a material to deform permanently due to a compressive stress
Malleability is required for stamping, forging and rolling

Question 3

What is the difference between ductility and brittleness?

Answer 3

Ductility is when the amount of plastic deformation is large
Ductile materials are fibrous, necking and dull
WHILE
Brittleness is when the amount of plastic deformation is little
Brittle materials are crystalline and rough and uneven

Question 4

What is the toughness of a material?

Answer 4

Toughness is the ability to undergo shock or impact load
To find the toughness is the area under the graph

Question 5

What is fatigue?

Answer 5

Fatigues is the ability to withstand repeated stress cycle, it only occurs only under cyclic repetitive loading.
This is crucial for the crankshaft

Question 6

What is creep?

Answer 6

Creep is when a metal undergo progressive plastic deformation under a constant load

Question 7

What are the conditions for creep to work?

Answer 7

1. Time
2. Temperature
3. Load or stress

Question 8

What is the process of the cold working?

Answer 8

• Apply the force for the material to plastically deform when it’s under the recrystallization temperature
• Minimum or yield Stress if needed
• High ductility is needed

Question 9

What are the 2 types of cold working processes?

Answer 9

1. Wire drawing
2. Deep drawing

Question 10

What is needed for a crankshaft?

Answer 10

Best combination of tensile strength and toughness

Question 11

What are the properties needed for cutting tools?

Answer 11

High hardness and wear resistance

Question 12

How to interpret the graph (Stress-strain curve) and relate it to the properties

Answer 12

Highest tensile strength: highest UTS point
Highest brittleness: lowest %E and % A and impact energy
Stiffness: gradient of the curve, young modulus
Toughness: highest impact energy
Hardness: highest hardness test

Question 13

What are the conditions for cooling rolling thin sheets

Answer 13

1. Good wear resistance
2. Mechanical strength
3. Toughness and fatigue resistance

Question 14

What are the conditions need for cold working process?

Answer 14

ductility