Metals Flashcards
Where do metals come from?
Metals come from metal ores
Why are metals non-renewable and unsustainable?
They come from ores and ores do not re-grow when we dig them up meaning metals are non renewable and unsustainable.
What is the ore of iron?
Magnetite and haematite
What is the ore of copper
Chalcopyrite
What is the ore of aluminium?
Bauxite
What is the ore of lead
Galena
What is the ore of tin?
Cassiterite
What is the ore of zinc?
Zinc blende
What is the structure of metals?
All metals are made up of crystals. Each crystal has a boundary that is firmly bonded to the boundary of a neighbouring crystal
How can you distinguish the nature of a metal?
It depends very much on the nature of the crystal?
What do we use to extract metal?
We use a blast furnace
How does a blast furnace work?
- Solid raw materials - iron ore, coke, limestone - are added from the top of the blast furnace.
- Hot air is blown in to the bottom of the blast furnace and provides the oxygen for the coke (carbon) to burn.
- Iron oxide in the iron ore reacts and changes to iron. Molten iron trickles to the bottom of the furnace.
- Limestone reacts with impurities to form a slag that floats on the iron.
- Waste gases are removed to a treatments plant.
What are ferrous metals?
These are metals that contain iron.
They also corrode if unprotected but are attracted to magnet as well.
What are non-ferrous metals?
These are metals that do not contain iron.
They do not corrode as much compared to ferrous metals and are not attracted to metals.
Why is iron a commercially useful material?
It is generally soft and ductile which is commercially useful.
If you increase carbon to a material, what happens?
- The metal becomes harder
- Toughness reduces - cast iron is brittle under impact
- Both medium and high carbon steel can be heat treated to make them harder and stronger
How to extract aluminium?
Aluminium is extracted from aluminium is extracted aluminium oxide (bauxite) by electrolysis. Electricity passes between the electrodes and pure aluminium forms at the cathode.
Properties and uses of aluminium
Non-ferrous
Properties: Lightweight, ductile, malleable, corrosion resistant, electrical and thermal conductor, can be metal inert gas (MIG) and tungsten inert gas (TIG) heat welded.
Melting temperature 660˚C.
Uses: Drinks cans, aircraft bodies, bike frames, window frames, packaging, baking foil
Copper properties and uses
Non-ferrous
Properties: Ductile, malleable, tough, corrosion resistant, good electrical and thermal conductor, can be soldered and brazed.
Melting temperature 1,083 ˚C.
Uses: Electrical wire, printed electrical circuits, water pipes, hot water tanks, central heating pipes
Zinc properties and uses
Non-ferrous
Properties: Low melting point, good corrosion resistance.
Melting temperature 420 ˚C.
Uses: Galvanising steel as a protective coating for dustbins, buckets, farm gates; intricate die castings
Silver properties and uses
Non-ferrous
Properties: Malleable, ductile, corrosion resistant, can be soldered. Melting temperature 962 ˚C.
Uses: Jewellery, cutlery, used for plating other materials
Gold properties and uses
Non ferrous
Properties: Malleable, ductile, corrosion resistant, can be soldered. Melting temperature 1,063 ˚C.
Uses: Jewellery, electronic components, connectors, switch components
Titanium properties and uses
Non ferrous
Properties: Hard, similar strength to steels but more lightweight, high resistance to corrosion.
Melting temperature 1,668 ˚C.
Uses: Joint replacements, tooth implants, spectacle frames, aircraft, spacecraft, golf clubs, bicycles, ship hulls
Tin properties and uses
Non ferrous
Properties: Ductile, malleable, low melting point, corrosion resistant.
Melting temperature 232 ˚C.
Uses: Soft solder, coatings for food cans, rarely used in pure form
Low carbon steel properties and uses
Ferrous
Properties: Ductile, high tensile strength, tough, malleable, poor resistance to corrosion.
15–0.30 per cent carbon content.
Melting temperature 1,427 ˚C.
Uses: Nuts, bolts, washers, screws, car bodies, outer panels for white goods
Medium carbon steel properties and uses
Ferrous
Properties: Harder than low carbon steel but less ductile, malleable and tough. 30–0.70 per cent carbon content.
Uses: Springs, gardening tools (trowels, forks)
Cast iron properties and uses
Ferrous
Properties: Hard outer skin but brittle core, good under compression.
3.5 per cent carbon.
Melting temperature 1,149 ˚C.
Uses: Disc brakes, machine parts, engine blocks; sheet furniture, for example decorative bollards, bins and lighting
Stainless steel properties and uses
Ferrous alloys
Properties: Tough, hard, corrosion resistant.
18 per cent chrome, 8 per cent nickel.
Melting temperature 1,510 ˚C.
Uses: Sinks, kitchenware, cutlery
High speed steel (HSS) properties and uses
Ferrous alloys
Properties: Hard, tough, high level of resistance to frictional heat. 18 per cent tungsten, 4 per cent chromium, 1 per cent vanadium, 0.5–0.8 per cent carbon.
Uses: Tool blades, drill bits, milling cutters, router bits
Die steel properties and uses
Ferrous alloys
Properties: Hard, tough.
Uses: Blanking punches and dies, extruder dies, fine press tool
Bronze properties and uses
Non-Ferrous alloys
Properties: Tough, corrosion resistant, can be cast.
90 per cent copper, 10 per cent tin.
Melting temperature 850–1000 °C.
Uses: statues, coins, bearings
Brass properties and uses
Non-ferrous alloys
Properties: Corrosion resistant, good electrical and thermal conductor, low melting point, casts well.
65 per cent copper, 35 per cent zinc.
Melting temperature 930 °C.
Uses: Boats fittings, door furniture, cast valves and taps, ornaments
Duralumin properties and uses
Non-ferrous alloys
Properties: Equivalent strength properties to low carbon steel but more lightweight, ductile, becomes harder as it is worked.
4 per cent copper, 1 per cent magnesium and manganese
Uses: Aircraft parts, vehicle parts
Pewter properties and uses
Non-ferrous alloys
Properties: Malleable, low melting point, casts well.
85–99 per cent tin, with the remainder consisting of copper and antimony.
Melting temperature 170–230 °C.
Uses: Tankards, flasks, goblets, photo frames, decorative items, candlesticks, sports trophies
Stock forms of metals
Sheet, Plate, Bar, Tube, Structural
Sheet stock form
Sheet is large flat sections of metal in varying thicknesses from less than 1 mm up to approximately 3 mm
Plate stock form
Plate is generally thicker than 3 mm and narrower than sheet metals.
Bar stock form
Bar is solid form, flat bar, square bar, round bar or hexagonal bar
Tube stock form
Tube form is hollow in cross section and can be square, rectangular (also called box section), round or hexagonal.
