Metals and alloys

Types of metal-based materials and their uses

Metals are found naturally and are mined from the earth. Metals used in products are extracted from the natural ore using large heat furnaces.

Ferrous metals

Ferrous metals contain iron and are magnetic. They are prone to rust.

Ferrous metalPhysical propertiesWorking properties
Low-carbon steel (mild steel)An alloy that is grey and smooth, rusts if not protectedDuctile and tough, easy to form, braze and weld, versatile, useful for construction, nuts, bolts, bike frames
Cast ironDull grey, rusts easilyBrittle if thin, can be cast in a mould, used for manhole covers, pans and gates
High-carbon steel (tool steel)An alloy that is grey, smooth and does not rust easilyHard-wearing, harder than low-carbon steel so less ductile but good for making tools, sharpens well
Rusted metal framework at a pier overhanging the blue sea.
Orange, flaking rust on an old steel pier

Non-ferrous metals

Non-ferrous metals do not contain iron and are not magnetic. They do not rust.

Non-ferrous metalPhysical propertiesWorking properties
AluminiumLight grey with a matt finishLightweight but strong and ductile, used for drink cans, kitchen utensils and some parts in transport
CopperRose coloured, polishes well but can oxidise to a green colour (verdigris)Good electrical conductor, can be polished, welds easily, used for plumbing parts and electrical cable
TinSilver colouredSoft and malleable, easy to form, used to make food cans
ZincSilvery blue with a matt finishBrittle with average malleability and conductivity, often used to galvanise steel
A historic collection of axes showing copper oxidising to a green colour (verdigris).

Copper oxidised to a green colour (verdigris)

Alloys

Alloys are mixtures of metal with an element to improve its properties or aesthetic. For example brass is a mixture of copper and zinc. Alloys can also be classified as ferrous or non-ferrous.

AlloyPhysical propertiesWorking properties
BrassNon-ferrous metal that is gold coloured and darkens when oxidised with ageAn alloy of copper and zinc, can be cast and machined, used for musical instruments and ornamental hardware
Stainless steelFerrous metal that is silver when polished, resists rustAn alloy of chromium, nickel and manganese, hard and smooth, used for cutlery and sinks
High-speed steelFerrous metal is dark grey when used for tool bitsCan be alloyed with a variety of materials for different properties, can withstand high temperatures, used for drill bits and saw blades