Exam Style Questions: Performance Characteristics of Metals Flashcards
State advantages and disadvantages of gold in the manufacture of the bench (2 marks)
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
State advantages and disadvantages of aluminium in the manufacture of the bench (2 marks)
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
State advantages and disadvantages of low carbon steel in the manufacture of the bench (2 marks)
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
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)
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.
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)
- 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
Give two reasons why sheet metal is used in the manufacture of car bodies (2 marks)
Give two reasons why sheet metal is used in the manufacture of car bodies (2 marks)
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.
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)
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
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)
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
Give three characteristics of silver and suggest one suitable application (3 marks)
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
Give three characteristics of stainless steel and suggest one suitable application (3 marks)
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.
Give three characteristics of grey cast iron and suggest one suitable application (3 marks)
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.
Explain why, despite having great electrical conductivity, silver is not as widely used in electronics as copper or gold (4 marks)
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.
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)
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
Give one example of a metal that is difficult to join using heat processes (1 mark)
- Stainless steel
- Aluminium
