7. Performance characteristics of metals Flashcards
What are the stock forms of metals?
- sheet
- large flat sections of metal in varying thicknesses from less than 1mm up to 3mm
- plate
- generally thicker than 3mm
- narrower than sheet metals
- bar
- solid form
- flat bar, square bar, round bar, hexagonal bar
- tube form
- hollow in cross section
- square, rectangular, round or hexagonal
- structural angular
- shapes such as H beams, L beams, I beams, tee bar and channel
What are the 3 main categories that metals can be split into?
- ferrous metal
- metal containing mostly iron and carbon
- non-ferrous metal
- metal that does not contain iron
- alloy
- metal made of two or more metals
- combination of two or more elements, one of which must be a metal
What are non-ferrous metals?
(examples)
- aluminium
- copper
- zinc
- silver
- gold
- titanium
- tin
What are the properties of aluminium?
- lightweight
- ductile
- malleable
- corrosion resistant
- electrical and thermal conductor
- can be MIG welded
- can be TIG heat welded
- melting temp 660
What are the uses of aluminium?
- drinks cans
- aircraft bodies
- bike frames
- window frames
- saucepans
- cooking utensils
- packaging
- baking foil
What are the properties of copper?
- ductile
- malleable
- tough
- corrosion resistant
- good electrical and thermal conductor
- can be soldered and brazed
- melting temp 1083
What are the uses of copper?
- electrical wire
- printed electrical circuits
- water pipes
- hot water tanks
- central heating pipes
What are the properties of zinc?
- low melting point (420)
- good corrosion resistance
What are the uses of zinc?
- galvanising steel as a protective coating for dustbins, buckets, farm gates
- intricate die castings
What are the properties of silver?
- malleable
- ductile
- corrosion resistant
- can be soldered
- melting temp 962
What are the uses of silver?
- jewellery
- cutlery
- used for plating other materials
What are the properties of gold?
- malleable
- ductile
- corrosion resistant
- can be soldered
- melting temp 1063
What are the uses of gold?
- jewellery
- electronic components
- connectors
- switch components
What are the properties of titanium?
- hard
- similar strength to steels but more lightweight
- high corrosion resistance
- melting temp 1668
What are the uses of titanium?
- hip replacements
- joint replacements
- tooth implants
- spectacle frames
- aircraft
- spacecraft
- golf clubs
- bicycles
- ship hulls
What are the properties of tin?
- ductile
- malleable
- low melting point of 232
- corrosion resistant
What are the uses of tin?
- soft solder
- coatings for food cans
- rarely used in pure form
What are ferrous metals?
(examples)
- low carbon steel
- medium carbon steel
- cast iron
What are the properties of low carbon steel?
- ductile
- high tensile strength
- tough
- malleable
- poor resistance to corrosion
- 0.15 - 0.30% carbon content
- melting temp 1427
What are the uses of low carbon steel?
- nuts
- bolts
- washers
- screws
- car bodies
- outer panels for white goods
What are the properties of medium carbon steel?
- harder than low carbon steel but less ductile, malleable and tough
- 0.30 - 0.70% carbon content
- melting temp range 1425 - 1540
What are the uses of medium carbon steel?
- springs
- gardening tools
What are the properties of cast iron?
- hard outer skin
- brittle core
- good under compression
- 3.5% carbon
- melting temp 1149
What are the uses of cast iron?
- disc brakes
- machine parts
- engine blocks
What are ferrous alloys?
(examples)
- stainless steel
- high speed steel (HSS)
- die steel (tool steel)
What are the properties of stainless steel?
- tough
- hard
- corrosion resistant
- 18% chrome
- 8% nickel
- melting temp 1510
What are the uses of stainless steel?
- sinks
- kitchenware
- cutlery
What are the properties of high speed steel (HSS)?
- hard
- tough
- high level of resistance to frictional heat
- 18% tungsten
- 4% chromium
- 1% vanadium
- 0.5 - 0.8% carbon
What are the uses of HSS?
- tool blades
- drill bits
- milling cutters
- router bits
What are the properties of die steel?
- hard
- tough
What are the uses of die steel?
- blanking punches and dies
- extruder dies
- fine press tools
What are non-ferrous alloys?
(examples)
- bronze
- brass
- duralumin
- pewter
What are the properties of bronze?
- tough
- corrosion resistant
- can be cast
- 90% copper
- 10% tin
- melting temp 850 - 1000
What are the uses of bronze?
- statues
- coins
- bearings
What are the properties of brass?
- corrosion resistant
- good electrical and thermal conductor
- low melting point 930
- casts well
- 65% copper
- 35% zinc
What are the uses of brass?
- boat fittings
- door furniture
- cast valves and taps
- ornaments
What are the properties of duralumin?
- equivalent strength properties to mild steel but more lightweight
- ductile
- becomes harder as it is worked
- aluminium with 4% copper and 1% magnesium and manganese
What are the uses of duralumin?
- aircraft parts
- vehicle parts
What are the properties of pewter?
- malleable
- low melting point 170 - 230
- casts well
- 85 - 99% tin, with remainder copper and antimony
What are the uses of pewter?
- tankards
- flasks
- goblets
- photo frames
- decorative items
- candlesticks
- sports trophies
