Types of Ferrous metals
Mild Steel, Iron, Cast Iron, High Speed Steel, Pyrite, Stainless Steel
Ferrous metal properties
- Contains ferrite/iron, so will oxidise (rust)
- Almost all are magnetic
- Produced in blast furnaces
- Carbon is added to produce different grades of metals
Alloys
- Formed by mixing two or more metals, to improve their properties
- Grouped into ferrous and non-ferrous alloys
Ore
All metals are found in the form of oxides or sulphates. Need to be extracted from ore before any useful processing
Non-ferrous examples
Aluminium, Tin, Copper, Titanium, Silver, Nickel, Gold, Cobalt, Brass, Magnesium, Mercury, Lead, Zinc, Pewter, Gallium, Paccadium
Non-ferrous properties
- Contain no iron
- Mainly produced by electrolysis
- Expensive production (electrical energy cost)
Aluminium cost 5% of manufacture price to recycle
Microstructure
Metals are made of crystalline structures.
3 forms of regular ‘lattice’ patterns
- close packed hexagonal
- body centred cubic
- face centred cubic
Close Packed Hexagonal (CPH)
- Zinc, Magnesium
- Weak, poor strength to weight ratio
Face Centred Cubic (FCC)
- Aluminium, Copper, Gold, Silver, Lead
- Very ductile, good electrical conductors
Body Centred Cubic (BCC)
- Chromium, tungsten
- Hard, tough
High Speed Steel (HSS)
Used to drill into other metals
Press formed
- Cold sheet
- Male/female mould
- Quick, efficient
Extrusion
Profiling one pattern through a die, then cooled
Die cast
- Lots of detail
- Moulded (expensive to make mould)
- Molten metal poured
- Lots can be produced
Sand casting
- Not perfect, not much detail
- Quick/efficient
- Can cast a range of sizes (eg postbox)
- Cost effective
- Piece must be finished
