Work Hardening
Many metals will harden and become more brittle as you bend or hammer them in to new shapes.
Annealing
Heat the metal up above its recrystallisation temperature
- decreases the hardness
- restoring the ductility to so it be further worked on without cracking
Hardening
Heating the steel to red hot and then quenching to reduce temperature fast
- becomes brittle
Tempering
Reheating the metal to a lower temperature than first time around and then leaving to cool more slowly
(AFTER HARDENING)
Define Non-Ferrous Metals and give examples.
Metals that do not contain iron
- Aluminium, zinc, copper, brass, bronze, silver, gold
Define Ferrous Metals and give examples.
Metals that do contain iron
- Steel, Iron
Define ‘Alloy’.
A metallic substance composed of two or more elements.
Advantages of Aluminium.
- can be easily coloured by anodization
- electrical and thermal conductor
- highly reflective when polished
- ductile
- malleable
- impermeable and odourless
- non-magnetic
- lightweight
- easily recycled
- easy to work and machine
Disadvantages of Aluminium.
- difficult to weld
- painting processes directly do not bond well
- anodizing is an expensive finishing process
- not particularly hard (scratches easily)
Advantages of Copper.
- good electrical and thermal conductor
- very malleable and ductile
- tough
Disadvantages of Copper.
- not corrosion resistant
- poor tensile strength
- expensive
- not hard (easily scratched)
Advantages of Silver.
- malleable
- thermal and electrical conductor
- antibacterial
- dense material (difficult to counterfeit)
Disadvantages of Silver.
- soft and scratches easily
- not especially corrosion resistant
- expensive
Advantages of Pewter
Disadvantages of Pewter
Advantages of Stainless Steel.
Disadvantages of Stainless Steel.
Advantages of Brass.
Disadvantages of Brass.
