Materials Science Quiz 2

Question 1

Metals or alloys having high percentage of iron
These Materials are used where high strength is required at relatively low cost

Answer 1

Ferrous Materials

Question 2

3 types of ferrous materials

Answer 2

1. Steel - Alloy of iron and carbon (1.5 %)
2. Cast Iron - Alloy of iron and carbon (4.5%)
3. Wrought Iron - Almost pure Iron (99.9%)

Question 3

Classification of Steels

Answer 3

1. Low Carbon Steel
2. Medium Carbon Steel
3. High Carbon Steel

Question 4

Classification of Iron

Answer 4

1. Grey Cast Iron
2. White Cast Iron
3. Malleable Cast Iron
4. High Duty Cast Iron
5. Alloy Cast Iron

Question 5

Metals Other than Iron
In Pure Form, they are used with other materials in order to obtain a certain property like corrosion resistance, ductility, hardness, etc.

Answer 5

Non-Ferrous Materials

Question 5

Deformation of temperature high enough for recrytallization
Large Deformations

Answer 5

Metal Fabrication (Hot Working)

Question 6

Deformations below recrystallization
Strain Hardening occurs
Small deformations

Answer 6

Metal Fabrication (Cold Working)

Question 7

Types of Forming (Metal Fabrication)

Answer 7

1. Forging
2. Hammer Forging
3. Press Forging
4. Drawing
5. Rolling
6. Extrusion

Question 8

Deformation process in which work thickness is reduced by compressive forces exerted by two opposing rolls

Answer 8

Rolling

Question 9

A cold working process in which the work piece is pulled through a tapered hole in a die so as to reduce its diamater

Answer 9

Drawing

Question 10

Forming a preheated workpiece by using a force created by hydraulically driven ram causing the metal to be squeezed into the die cavity by the static pressure

Answer 10

Press Forging

Question 11

a process used to create an objects of a fixed cross-sectional profile. A material is pushed through a die of the desired cross-section

Answer 11

Extrusion

Question 12

the process of producing metal/alloy component parts of desired shapes by pouring the molten metal/alloy into a prepared mould and then allowing the metal/alloy to cool and solidify

Answer 12

Casting

Question 13

a process of using sand as the primary material to mold various metallic products

Answer 13

Sand Casting

Question 14

includes wax pressure, wax repair, group tree, dip slurry, wax melting, casting metal liquid and post processing process

Answer 14

Investment Casting

Question 15

3 stages of investment casting

Answer 15

Stage 1 - Mold formed by pouring plaster of paris around wax pattern
Stage 2 - Wax is melted and then poured from mold-hollow mold cavity remains
Stage 3 - Molten Metal is poured into mold and allowed to solidify

Question 16

A metal casting process that is characterized by forcing molten metal under high pressure into a mold cavity

Answer 16

Die Casting

Question 17

A process of joining similar and dissimilar metals or other material by application of heat

Answer 17

Welding

Question 18

Five Major factors of weldability

Answer 18

1. Melting Point
2. Thermal Conductivity
3. Thermal Expansion
4. Surface Condition
5. Change in microstructure

Question 19

Welding Classification

Answer 19

1. Plastic Welding - piece of metal is heated to plastic state then forced together by external pressure
2. Fusion Welding - material is heated together into molten state then solidified
3. Cold Welding - applies pressure to the joint that result in diffusion or inter-surface molecular fusion

Question 20

a welding process, in which two work pieces are joined under a pressure providing an intimate contact between them and at a temperature essentially below the melting point of the parent material

Answer 20

Solid State Welding

Question 20

Solid state welding Advantages

Answer 20

1. Weld is free from microstructure defects
2. Mechanical Properties of the weld are similar to the parent material
3. No consumable materials (Fillers, fluxes) are required
4. Dissimilar objects may be joined

Question 21

A process, in which low carbon steel parts are heated to about 1000 C ( 1800 F) and then forged (Hammered)

Answer 21

Solid state welding type - Forge Welding

Question 21

Forge Welding advantages

Answer 21

1. Good quality welding is obtained
2. Parts of intricate shape can be welded easily
3. No filler material is required

Question 22

Forge Welding disadvantages

Answer 22

1. Only low carbon steel may be welded 2. High level operating skill is required 3. Slow welding process 4. weld may be contaminated by the coke used in the heating furnace

Question 23

a process, in which two work pieces are joined together at room temperature and under a pressure, causing substantial deformation of the welded parts and providing intimate contact between the welded surfaces

Answer 23

Solid state welding type - Cold Welding

Question 24

in which two cylindrical parts are brought in contact by a friction pressure when one of them rotates

Answer 24

Solid state welding type - Friction Welding

Question 25

In which parts are metallurgical bonded as a result of oblique impact pressure exerted on them by a controlled detonation of explosive charge

Answer 25

Solid state welding type - Explosive Welding

Question 26

Explosive Welding Advantages

Answer 26

1. Large surfaces may be welded 2. Low cost and simple process 3. Surface preparation is not required

Question 27

Explosive Welding disadvantages

Answer 27

1. Brittle materials can not be processed 2. Thickness of Fyler plate is limited 3. Safety and security aspects of storage and using explosives

Question 28

In which pressure is applied to two work pieces with carefully cleaned surfaces and at elevated temperature below the melting point of the materials

Answer 28

Solid state welding type - Diffusion welding

Question 29

Diffusion welding advantages

Answer 29

1. Dissimilar materials may be welded 2. High quality welding is obtained 3. No limitation in thickness of work pieces

Question 30

Diffusion welding disadvantages

Answer 30

1. Time consuming process with low productivity 2. Very thorough surface preparation is required 3. Relatively high investment in equipment

Question 31

In which two work pieces are bonded as a result of a pressure exerted to the welded parts combined with application of high frequency

Answer 31

Solid state welding type - Ultrasonic welding

Question 32

Ultrasonic welding advantages

Answer 32

1. Dissimilar metals can be joined 2. Very low deformation of the work pieces surface 3. High quality weld is obtained 4. The process may be integrated into automated production lines 5. Moderate operator skill level is enough

Question 33

Ultrasonic welding disadvantages

Answer 33

1. Work pieces may bond to the anvil 2. Only small and thin parts can be welded

Question 34

a fusion welding process in which high velocity electron beam is used to join metals together

Answer 34

Electron beam welding

Question 35

It is used to generate, accelerate, and align the electron beam in a desired direction and spots on the w/p

Answer 35

Electron gun

Question 36

Parts of electron gun

Answer 36

1. Cathode 2. Anode 3. Grid Cup 4. Focusing unit

Question 37

Electron beam welding parts

Answer 37

1. Electron gun 2. Power supply 3. Vacuum Chamber - composed of diffusion pump and mechanical pump 4. Work Handling devices

Question 38

Electron beam welding advantages

Answer 38

1. High welding speed 2. Welding of dissimilar metal can be done 3. High weld quality and precision 4. Less operating cost 5. Materials with high welding temperature can be welded easily 6. Less distortion due to less affected heat zone 7. Cost of cleaning is negligible

Question 39

Electron beam welding disadvantages

Answer 39

1. Cost of equipment is very high 2. High skill operator is required to operate it 3. High vacuum is required 4. Due to operation if vacuum, large jobs can not welded 5. High safety measures are need to work with it

Question 40

Electron beam applications

Answer 40

1. Aerospace industry, jet components 2. Power generation industry 3. space industry to build titanium tanks and sensors 4. It is used in automobile industry to manufacture transmission system 5. It is used in electrical and electromechanical industry to manufacture parts of copper structure 6. Nuclear industry and medical industry

Question 41

a type of liquid state welding process in which fuel gases burns to generate heat which is further used to melt interface surfaces of welding plates which are held together to form a joint

Answer 41

Gas welding

Question 42

Gas welding advantages

Answer 42

1. It is easy operate and dose not required high skill operator 2. Equipment cost is low compare to other welding process 3. it can be used at site 4. Equipment's are more portable than other type of welding

Question 43

Gas welding disadvantages

Answer 43

1. It provides low surface finish, This process needs finishing after welding 2. Have large, affected heat zone 3. Higher safety issue due to naked flame of high temperature 4. It is suitable only for soft and thin sheets 5. Slow metal joining rate 6. No shielding area which causes more welding defects

Question 44

a liquid state welding process in which the metal to metal joint created in liquid or molten state

Answer 44

Resistance welding

Question 45

it is a simplest type of resistance welding in which the work pieces are held together under pressure of anvil face

Answer 45

Resistance welding - spot welding

Question 46

Annealing process of heating the metal slightly above the critical temperature

Answer 46

Annealing

Question 47

Annealing advantage

Answer 47

1. It softens the metal 2. Enhances and improves the machinability of metal 3. Increases ductility 4. It enhances toughness of metal