FOUND/MADE
earths crust found as ores 1. ore crushed 2. melted in furnace 3. molten metal sinks to bottom
ADVANTAGES-SUSTAINABLE
- long lastin
- some can be recycled
DISADVANTAGES-SUSTAINBLE
- damages the envoirment
- transport takes a lot of energy
- metal ores are a finite resource
3 TYPES
- ferrous
- non-ferrous
- alloy
MALLEABLE
can be easily moulded into shape e.g copper
DUCTILE
can be drawn out into a wire e.g copper
TOUGH
is more resistant to impact e.g tool steel
BRITTLE
can break when bent e.g cast iron
HARD
resistant to scratching e.g HHS, steel, brass
STOCK FORMS
- sheet
- bar
- tube
- strip
- angle
ADVANTAGES OF SF
- easy to know what range you need to buy in
- you can design before buying because you know that it will all work out
PITCH
the distance travelled by a nut in one revolution
WORK-HARDENED
after metal has been hit, drilled, cut
- difficult to work with
- brittle
ANNEALING
controlled heating- easy to work with again
QUENCHING
putting hot metal in water
HARDENING
heating steel to a specific temperature, then cooling slowly can make it hard and tough
HEATING TO SPECIFIC TEMP FOR INTENDED PURPOSE
- PALE STRAW-230-scribers
- BROWN/PURPLE-270-scissors, press tools, knives
- BLUE-300-needles, springs, spanners
IRON—> STEEL
oxygen blown into molten iron to remove mostof the carbon
8 WAYS YOU CAN PUT A FINISH ON A METAL (a,p,g,b,p,p,p,s)
- anodising
- polishing
- galvanising
- buffing
- planishing
- plastic dip coating
- painting
- sand-blasting
BRAZING
- heat is provided from buring natural gases
- filler rod is melted into heated join and sticks the two pieces of metal together
SPOT WELDING
- weld sheet metals
- two copper alloy electrodes to concentrate the welding current + force
- much quicker and safer than wleding with gas
SOLDERING
-joins electronic components to a printed circuit board
-melted usinf a soldering iron.
(iron contains FLUX which makes it flow easily
