Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Design And Technology > Metals > Flashcards

Metals Flashcards

1
Q

Name the casting methods

A

Lost wax Investment
Sand
Low pressure die (gravity)
High pressure die

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the difference between ferrous and non-ferrous metals?

A

Ferrous contain iron, non-ferrous do not

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the main 4 examples of ferrous metals?

A

Mild steel (low carbon)
Medium carbon steel
High carbon steel
Cast iron

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Properties of mild steel

A

Ductile
High tensile strength
Tough
Malleable
Poor resistance to corrosion
Least amount of carbon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Medium carbon steel properties

A

Harder than low carbon
Less ductile, malleable and tough
Higher carbon content

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Cast iron properties

A

Harder outer skin
Brittle core
Good under compression

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Mild steel uses

A

Nuts
Bolts
Washers
Screws
Car bodies
Fences

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Medium carbon steel uses

A

Springs
Gardening tools
Railways.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Cast iron uses

A

Machine parts
Cookware

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Problem with ferrous metals

A

Tendency to rust due to iron content

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Non ferrous metal examples

A

Aluminium
Zinc
Tin
Copper

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Properties of aluminium

A

Lightweight
TIG welded
Conductor
Malleable
Ductile

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Uses of aluminium

A

Drinks cans
Aircraft bodies
Bike frames
Baking foil

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Zinc properties

A

Low melting point
Good corrosion resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Zinc uses

A

Galvanising steel for protection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Tin properties

A

Ductile
Malleable
Low melting point
Corrosion resistant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Tin uses

A

Solder
Food cans coating
(Rarely used in pure form)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Copper properties

A

Ductile
Malleable
Tough
Corrosion resistant
Good conductivity
Soldered or brazed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Copper uses

A

Electrical wire
Water pipes
Water tanks
Central heating pipe

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is an alloy? How are they made?

A

Metals made of two or more metals, or combining two or more elements, one of which must be a metal. In order to optimise advantages of metals mechanical and physical properties.
Alloys are produced in either a furnace or in a casting process
Metals are melted together into specific quantities and then poured into bars for future products

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Examples of alloys

A

Stainless steel
Duralumin
Brass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Properties of stainless steel

A

Tough
Hard
Corrosion resistant
18% chrome, 8% nickel
High melting point

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Uses of stainless steel

A

Cutlery
Kitchenware
Sinks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Duralumin properties

A

4% copper, 1% magnesium and manganese
High tensile strength (same as mild steel)
More lightweight, ductile
Becomes harder when worked

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Duralumin uses

A

Aircraft parts
Vehicle parts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Brass properties

A

Corrosion resistant
Good conductivity
Low melting point (930 degrees)
Casts well

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Brass uses

A

Boat fittings
Door furniture
Taps
Ornaments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is the aim of heat treatment?

A

To alter the metals properties via heating and cooling its grain structure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Examples of heat treatment

A

Hardening
Tempering
Case hardening
Annealing
Normalising

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is hardening?

A

High and medium carbon steel is heated to a temp above recrystallisation. It is then held here for a given time to create a consistent temp. Then it is rapidly cooled in water, oil, air or salt water.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Outcomes of quench hardening

A

Increased hardness so products resists wear and fracture on surface
Does not change core properties

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What is tempering?

A

Typically follows a hardening process. Metal is heated to a temp just below critical temp for a certain time depending on the steel. It is then slowly air cooled. Temperature controls the reduction in hardness (higher the temp, more hardness removed).

33
Q

Outcomes of hardness

A

Increased machinability
Reduces brittleness as well as hardness
Increases ductility and toughness

34
Q

What is case hardening?

A

Case hardening hardens the surface of steels. Performed by carburising or quenching.

35
Q

What is carburising?

A

Case hardening process which changes chemical composition of surface of low carbon steel so it can absorb more carbon, increasing surface hardness.
Steel place in ceramic box packed with carbon
Heated to 940 degrees
Carbon atoms diffuse into materials structure
Depth of carbon layer determined by time in box
Product is heated to around 760 degrees and quenched.

36
Q

Annealing

A

Only metals with lower melting point like cast iron or steel. Relieves stress from work hardened metal.
Heated to high temp where internal stresses are relieved
Heated above recrystallisation temperature but below melting point
New grains formed and cooling allows them to develop

37
Q

Outcomes of annealing

A

Easier to work
Less brittle
More ductile

38
Q

What is elasticity

A

Ability to be deformed and then return to original shape when force removed

39
Q

What is plasticity?

A

Ability to be permanently deformed and retain deformed shape

40
Q

What is malleability?

A

Ability to withstand deformation by compression without cracking. It increases with temperature

41
Q

What is ductility?

A

Ability to be drawn out under tension, reducing the cross-sectional area without cracking (eg stretching a material into a wire)

42
Q

What is hardness ?

A

Ability to resist abrasive wear such as scratching, surface indentation or cutting

43
Q

What is toughness?

A

ability to absorb impact without fracture

44
Q

What is durability?

A

Ability to withstand general wear over a period of time

45
Q

What is biodegradability?

A

Ability to naturally decompose by actions of bacteria or other living organisms

46
Q

Electrical conductor

A

Allows flow of electricity
Provides little resistance to flow of charge

47
Q

Electrical insulator

A

Does not allow flow of charge

48
Q

Thermal conductor

A

Allows transfer of heat energy through material
Better conductors allow heat to transfer faster

49
Q

Thermal insulator

A

Prevents heat energy transfer

50
Q

Types of strength

A

Bending
Compressive
Tensile
Shear
Torsional

51
Q

Tensile strength meaning

A

Ability to resist stretching or pulling forces

52
Q

Shear strength meaning

A

Ability to resist slinging forces on parallel plane

53
Q

Torsional strength meaning

A

Ability to resist rotational forces from applied torque of tension

54
Q

Bending strength meaning

A

Ability to resist forces that may bend the material

55
Q

Compressive strength meaning

A

Ability to withstand being crushed or shortened by pushing force

56
Q

Types of casting

A

Sand
Investment
Low/high pressure die casting

57
Q

Draw a diagram of sand casting

A

Google

58
Q

Draw a diagram for investment casting

A

Google

59
Q

How does investment casting work?

A

The process-
1. A wax pattern is created (can be done in the form of a tree) from a master mould made from steel or aluminium
2. This is then dipped into the refractory clay slurry
3. This is fired in a kiln to bake the clay hard
4. Once final coat has hardened the wax is burned out
5. Molten mould then poured into cavity and solidified
6. Refractory mould then broken including the runner and any connecting channels

60
Q

Why use investment casting

A

Great surface finish
Intricate shapes can be made
Wax can be reused
Strength of products

61
Q

Why shouldn’t you use investment casting

A

Time consuming waiting for coast to harden
Expensive start up cost
Complex machinery
Difficult to make parts with hollow centre

62
Q

Uses of investment casting

A

Collectible figures
Jewellery
Construction

63
Q

How does sand casting work

A

The process-

1.Place the mould pattern (wood) (made using CAD) into a steel box called a ‘drag’
2. Packs and around the pattern and level it
3. Flip the drag over and and a second box called the ‘cope’ is clamped on top
4. Two sprue pins are then placed into the cope to create the runner and the riser
5. Pack sand into the cope around the sprue pins and other half of pattern
6. Separate the cope from the drag and remove the pattern and sprue pins. This should leave a cavity and channels. Cut connecting channels into the sand to connect the channels to the cavity and then connect cope and drag again
7. Pour molten metal through runner until the riser is filling telling us the cavity is full
8. Allow to cool and then remove the sand and cut off the runner and riser using a hacksaw.

64
Q

Why use sand casting

A

Be used for any quantity of products (affordability)
Relatively cheap
Use high melting point metals unlike die casting
Sand can be reused

65
Q

Why not sand casting

A

Rough surface finish due to grainy sand
Labour intensive
Less accurate than other methods
Moulds require constant checking and changing
Moulds are one use

66
Q

Uses of sand casting

A

Wood working clamps
Motor housings
Drain covers
Post box

67
Q

How does low pressure die casting work

A
  1. Die split in half and each side heated to high temperature to prevent metal cooling to quickly. A lubricant is also applied to maintain this temp
  2. Two half’s clamped together tightly using high pressure.
  3. Molten metal poured in and gravity pulls it down into the entire mould. Metal poured into runner and the riser tells us when it is full
  4. It is then left to cool and solidify fur a sufficient tie before removing the mould
  5. Ejector pins remove the cast from the machine
  6. Gates, runners, sprues and flash are all removed to creat finished product
68
Q

What metals can be die casted and why

A

Non ferrous metals due to lower melting point as most moulds are made from tool steel. If ferrous were used they would deform the mould as melting points are too similar

69
Q

How does case hardening work

A

Tongs and other PPE are used for safety
Metal heated until cherry red
Dipped into carbon powder
Once soaked the process repeats
Metal then reheated and quenched in water to rapidly cool

70
Q

Cons of gravity die casting

A

Slow as reliant on gravity
Create a low volume as a results of this
Very expensive to setup so only really used for mass produced items or large batches

71
Q

Pros of gravity die casting

A

Creates parts with thinner sections than sand casting but thicker than pressure die casting
Produces parts with excellent mechanical properties suitable for heat treatment
Less machinery than pressure die casting
Relatively smooth surface finish
Less porosity than pressure as no turbulence

72
Q

How does pressure die casting work?

A
  1. Molten metal stored in chamber or crucible.
  2. A pneumatic/hydraulic plunger forces a shot of the metal into the mould
    The high pressure forces the mould to fill allowing fine details to be moulded
  3. Once the metal has solidified ejector pins remove the mould from the cavity
    4.
73
Q

Pros of high pressure die casting

A

Fast process enabling high volumes to be produced
Can be automated as no need for runners and risers
Fine details can be moulded
Can make thin walled parts

74
Q

Cons of high pressure die casting

A

Expensive to set up
Turbulence from high pressure can cause porosity in components
Expensive dies

75
Q

What are the moulds in die casting made from?

A

Tool steel

76
Q

Uses of die casting

A

Alloy wheels
Toy cars
Door knobs
Handles

77
Q

How is plaster of Paris different to sand

A

Uses plaster of Paris instead of sand and can only use non-ferrous metals

78
Q

What is carburising?

A

Steel placed in ceramic box packed with carbon
Heated to 950 degrees
Carbon diffuses into steel building up surface content of carbon
Depth of layer determined by time (longer exposure means thicker layer)
Quenched to cool

79
Q

What is quenching?

A

Hot metal quenched in water to cool it rapidly and seal hard surface case without affecting inner properties

Design And Technology (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions