Iron and steel
Iron and steel are generally regarded as utilitarian metals, valued for their strength, but they have also been used for decorative purposes. Iron is converted into a metal (pig iron) by smelting iron-bearing ores, whilst steel is an alloy of iron and carbon. Modern steels contain additional elements introduced to give particular qualities, such as high tensile strength, increased hardness or corrosion resistance (e.g. stainless steel).
A magnet can usually be used to identify iron and steel as it will only stick to metals containing iron, although there are some modern steels which are not magnetic.
Historically, there were two main forms of iron - wrought iron and cast iron.
1. Wrought iron was the most commonly used form of ferrous metal for everyday objects (with the exception of weapons and blades) until the development of the steel industry in the 19th century. It is still available today for producing decorative ironwork. Wrought iron is tough, flexible and malleable, and also comparatively corrosion resistant. It was used for making a variety of objects from kitchen items to architectural pieces such as elaborate gates and balconies.
2. Cast iron, known in Europe from the late 14th century, is very hard and brittle. It has a dull grey porous surface that may have bumps and ridges, which are cast marks. It was first used for objects such as firebacks and, as casting technology improved, items such as railings, stoves, and weight-bearing architectural items. Cast iron reached its apogee in the 19th century, when even jewellery was made from cast iron, and British companies such as Coalbrookedale were able to mass produce cast iron objects such as benches and hatstands.
Until the 19th century, steel was only produced in small quantities in Europe and was used mainly for weapons and blades, and for specialist items such as watch springs, high status locks and keys. From the late 18th century onwards, steel began to replace wrought iron as the most commonly used metal for utilitarian items.
The 'cut steel' technique, which began in the 16th century and was most popular in the 18th century, was used for small items of personal adornment such as jewellery, buttons, shoe buckles and sword hilts. Small, highly polished, faceted steel studs were screwed or riveted onto a shaped steel backplate, for example this cut steel button.