Exam Style Questions: Performance Characteristics of Metals

Question 1

State advantages and disadvantages of gold in the manufacture of the bench (2 marks)

Answer 1

Advantages:
- Would not tarnish/corrode over time despite being used outdoors as
it is unreactive
- Will not lose/change colour over time
- Easily cast into a variety of shapes to create decorative bench
designs
- Ductile and malleable so could be formed into strong sections and
bent into shape easily saving time in manufacture

Disadvantages
- Very expensive as the metal is very rare and as such it could be a
target for theft
- Very dense and heavy so the bench would be difficult to transport
after manufacture which would increase costs further, and it would be
almost impossible to move after it is placed in position in the garden
- It would be difficult to protect during transportation and use
- It is not a very hard metal and so would be susceptible to scratching
and wear

Question 2

State advantages and disadvantages of aluminium in the manufacture of the bench (2 marks)

Answer 2

Advantages:
- Excellent strength to weight ratio would mean less material weight
would need to be used to hold the same maximum weight as a bench
made from heavier metals. It would be easy to move around the garden
- Resistant to corrosion so could withstand weathering without
deteriorating in quality does not require a finish
- Casts well
- Could be recycled easily
- Can be coloured through anodizing so a variety of styles could be
achieved

Disadvantages:

          - Difficult to weld so could cost more to manufacture than other metals
          - More expensive than low carbon steel

Question 3

State advantages and disadvantages of low carbon steel in the manufacture of the bench (2 marks)

Answer 3

Advantages:
- It is less expensive than aluminium and is easy to work and weld which
meaning lower manufacturing costs
- It is malleable and ductile so could be formed into a variety of designs
- Tough and impact resistant so could withstand storms and everyday
knocks

Disadvantages:
- Requires a finish to be applied as steel rusts easily when in contact with
air and water, maintenance costs may be incurred
- Heavier than aluminium meaning the bench would be more difficult to
move than one made from aluminium

Question 4

Bronze was used on ship hulls used to sail across the Atlantic as early as the 15th Century. It is also used for propellers and other nautical components and instrumentation.

a) Which properties of bronze made it suitable to be used at sea? (2 marks)
b) Name a suitable metal or alloy used to make ship hulls today (1 mark)
c) Explain why the metal or alloy named above is suitable to use on boat and ship hulls (4 marks)

Answer 4

a)
Tough – would help maintain shape and form and protect the hull from cracking if steered into rocks or shallow ground as it would absorb impact well
Corrosion-resistant – would not rust, rot or corrode after long periods in sea water which would often destroy wooden vessels.

b)

• Aluminium alloy
• Steel

c)
Aluminium alloy – great strength to weight ratio so high speeds can be reached without large amounts of fuel being required to propel the ship, corrosion resistant therefore does not require painting available in large sheets
Steel – high-grade steel is very strong and can withstand external and internal forces and loads even on large container ships, galvanised steel is corrosion resistant even in seawater, available in large sheets saving time and manufacturing costs, easy to weld, impact resistant and tough to withstand stormy conditions at sea, abrasion resistant and durable.

Question 5

At the top end of the BBQ market, manufacturers are increasingly using titanium in the manufacture of products. A kettle BBQ costs around £30, however, a titanium portable gas BBQ grill may cost upwards of £150.

Explore the arguments for using titanium and discuss whether they justify the vastly increased cost (6 marks)

Answer 5

• Better build quality due to the use of more expensive material
• Titanium is a low-density metal so the product would be light and portable
• Better corrosion resistance so greater longevity
• Hard and resistant to wear
• Titanium can withstand extremes of temperature
• It has good reflective properties and is non-reactive making it ideal for cooking quickly, efficiently, and safely
• Titanium coatings (as may be used on the grill) are non-stick

Question 6

Give two reasons why sheet metal is used in the manufacture of car bodies (2 marks)

Question 7

Give two reasons why sheet metal is used in the manufacture of car bodies (2 marks)

Answer 7

Award 1 mark for each correct response up to 2 marks.

• Sheet metal offers a large surface area which lends itself to pressing/punching in manufacture.
• Sheet metal is relatively lightweight when press formed, due to the lack of fixtures and fittings/welds and the thickness of the material.
• Sheet steel offers a smooth consistent surface for finishing.

Question 8

A range of metals, including titanium and its alloys, are used in the manufacture of an aeroplane’s fuselage and wings.

a) Name one other metal or alloy that could be used for these applications (1 mark)
b) Evaluate the use of titanium in aviation engineering (6 marks)

Answer 8

a) Duralumin, aluminium.

b)
- High tensile strength will keep its shape even when subject to external forces and internal loads during take-off, flight and landing, making it suitable to be used for turbine blades, wing beams, and landing gear
- Low density will reduce overall weight and the fuel consumption of the aircraft
- Has a high strength to weight ratio meaning less material can be used in engine parts whilst still withstanding the same loads and forces
- High corrosion resistance means it can withstand chemicals and other corrosive fluids required in aircraft turbine engines and fuel tanks
- Can withstand high temperatures without creeping or distorting making it suitable for use in engine compartments (which can reach up to 2,100 degrees Celsius), boosters, compressor blades, casings, and heat shields
- Good durability reduces the need to replace parts frequently
- It is more expensive than other metals such as aluminium alloys and steel
- Difficult to machine and shorter tool life in manufacture, means it is costly and time consuming to manufacture and replace parts
- Titanium is a relatively rare metal and therefore has a higher selling price

Question 9

Give one physical and one mechanical property of the copper hot water pipes. In each case state why the property is suitable for the product pictured (4 marks)

Answer 9

Award 2 mark for property 2 mark for relevant explanation

Physical property:
Resistance to corrosion – will not corrode and crack leaking water, will not contaminate the water supply
Thermal conductivity – very good conductor of heat meaning water heated in the boiler will keep its heat as it travels through the pipes

Mechanical property:
Ductile – can be drawn in long sections of pipe without breaking or cracking
Malleable – can be bent at angles without cracking to go around walls, kitchen units, and floors to route the water to any part of the house or room

Question 10

Give three characteristics of silver and suggest one suitable application (3 marks)

Answer 10

Award 1 mark per relevant point up to a maximum of 3 marks and 1 mark for a correct application

Characteristics:
Reflects light well, is an excellent conductor of electricity and highest thermal conductivity of any metal, strong, malleable can be shaped into numerous decorative forms, and endures extreme temperatures, very ductile so it can be drawn into wires.

Application:
Dentistry, electronics, jewellery, mirrors, telescopes, microscopes, solar cells, high capacity batteries

Question 11

Give three characteristics of stainless steel and suggest one suitable application (3 marks)

Answer 11

Award 1 mark per relevant point up to a maximum of 3 marks and 1 mark for a correct application

Characteristics:
Hygienic and food safe, does not affect the flavour of food, good corrosion resistance can be cleaned with chemicals and will resist weathering outdoors well and does not require an additional finish, very hard and good impact resistance, good heat resistance important to resist fire and be flame proof in buildings, good tensile strength use in cables and bridges.

Application:
Responses may include: Kitchenware, cutlery, knives, saucepans, dishwashers, sinks, cladding, construction, surgical instruments, MRI scanners, nuts and bolts, exhausts, car trim, door and window fittings. Accept any suitable application.

Question 12

Give three characteristics of grey cast iron and suggest one suitable application (3 marks)

Answer 12

Award 1 mark per relevant point up to a maximum of 3 marks and 1 mark for a correct application

Characteristics:
Responses may include: Good compressive strength resisting deformation but relatively low tensile strength. Hard with good abrasion resistance but not tough, it is brittle and has low impact resistance so will crack or shatter if dropped. It can maintain a relatively high heat and distributes it evenly. Good resistance to oxidation so does not need finishing. Casts well with little shrinkage.

Application:
Responses may include: Casserole dishes, pans and skillets. Radiators, stoves, manhole covers and drain grills, railings, architectural features and garden furniture. Machine parts, disc brakes and engine blocks Accept any suitable application.

Question 13

Explain why, despite having great electrical conductivity, silver is not as widely used in electronics as copper or gold (4 marks)

Answer 13

Silver tarnishes easily when exposed to sulphur compounds in air or water, as it does not have particularly good corrosion resistance, unlike gold and copper which both have much better resistance to corrosion. Therefore, over time the silver would stop transferring electrical signals as it would likely be exposed to air and moisture when in use in electronics.

Silver is slightly less malleable than gold and not as ductile as copper, therefore it is not as easy to draw silver into wires as it is with copper, nor to plate or leaf components as gold is used to do.

Question 14

A still is used to distill liquid by heating to boiling point and then cooling to condense the vapor. Stills are used to produce many products from distilled alcoholic beverages like gin and whisky to perfume and medicines.

With reference to both mechanical and physical properties, evaluate the use of copper in industrial alcohol still (6 marks)

Answer 14

Award 3 mark for property 3 mark for relevant explanation

• Copper is a good conductor of heat, so the still would get to temperature quickly and maintain it, saving time when bringing the still to the boil
• Copper is malleable so could be shaped efficiently into the desired designed form without breaking or cracking
• Copper can withstand being bumped in an industrial setting, it is tough and malleable, so it would deform rather than cracking and breaching the still
• Copper is easily joined using heat processes, so handles and other features could be added easily during manufacture
• Copper can be alloyed so could have enhanced properties at a relatively low cost to production
• Copper has good corrosion resistance in air and water and would not require a protective finish to be applied saving costs in production
• Copper has anti-microbial properties and the copper oxide helps remove sulfides from the liquid
• Copper is food safe meaning that the product could be used for human consumption

Question 15

Give one example of a metal that is difficult to join using heat processes (1 mark)

Answer 15

• Stainless steel

- Aluminium

Question 16

a) Name a suitable specific metal for the kettle (1 mark)

b) Explain why this metal is suitable for the kettle (2 marks)

Answer 16

a) Stainless steel
b) Award 1 mark for property 1 mark for a relevant explanation. Accept alternative correct responses.

Stainless steel is a malleable material - that can be spun/formed into the required shape.
Stainless steel has lower thermal conductivity compared with other metals.
Stainless steel has good aesthetic properties – looks good for a modern kitchen interior/self-finishing.
Stainless steel does not corrode - it maintains a good, clean, hygienic finish etc.

Question 17

Mild steel sheet is often used in the manufacture of ‘white goods’ such as washing machines, tumble dryers, and fridges.

(a) Explain two mechanical properties that make mild steel suitable for manufacturing white goods (4 marks)
(b) Explain two physical properties that make mild steel suitable for this application (4 marks)

Answer 17

a)
Award 1 mark for property and a further 1 mark for a relevant explanation.

• Mild steel is a malleable material which means it can be press-formed into the shape required. Once formed, it will retain this shape.
• Mild steel is malleable and ductile so it can stretch over a forming die without tearing or splitting.
• Mild steel has good impact toughness meaning it can absorb the energy of any impact by deforming without cracking or breaking which will protect the internal workings and electrics.

b)
Award 1 mark for property and a further 1 mark for a relevant explanation.

• Mild steel can be spot welded easily because it has good fusibility.
• Mild steel sheet can be drilled and machined easily enabling it to be joined mechanically.
• Mild steel will take a variety of finishes, e.g. acrylic and cellulose based paints, zinc-based coatings. This gives a high-quality finish and produces desirable aesthetic qualities.
• The application of a finish will improve the resistance to corrosion.

Question 18

Study the image below. With reference to both the physical and mechanical properties, evaluate the use of aluminium alloys in bicycle pedals (6 marks)

Answer 18

• Aluminium has a low density which means it will be more energy-efficient as it is lighter than other metals
• Aluminium alloys have a high strength to weight ratio
• Aluminium is malleable as can be machined or cast into the required complex shape of bicycle pedals
• Aluminium has good resistance to corrosion as the oxide layer makes it unreactive this means it will be able to withstand a variety of outdoor weather conditions without requiring additional maintenance due to corrosion
• Aluminium can be anodized and colour can be added during that process adding aesthetic qualities to the pedals as well as increased wear resistance
• Aluminium is not very hard, even when alloyed it will scratch more easily than steel which will increase the amount of servicing required over time, especially with the direct wear from foot pressure
• Aluminium is not particularly easy to join with heat processes and will however, mechanical fixings can be used to fabricate the bicycle pedals
• Aluminium pedals are generally more expensive than comparable steel pedals