Wire has thousands of uses, from cables and ropes for bridges, mining and fishing, to piano wire; from supermarket trolleys to medical instruments; from telecommunications and power cables to fencing.
Wire is usually made by mechanically pulling metal rods through a series of progressively smaller dies, a process known as ‘cold drawing’. Cold drawing reduces the diameter and changes the properties of the metal; it can be repeated several times, and the wire may be heat treated between passes to counteract hardening and restore ductility. Wire is usually circular, but it can be made with any section by varying the die holes. It can also be galvanized and/or coated to provide corrosion protection. Steel, copper, aluminium and nickel are used to make wire, the choice depending on its use. Dies are made from tungsten carbide or diamond.
Precious metals have been used to make wire for jewellery since antiquity. The Egyptians were drawing strips of metal through stone beads by the 2nd dynasty, and a swaging technique (a metal rod struck between grooved metal blocks) may have been used in Bronze and Iron Age Europe. Wire has been drawn in England since mediaeval times to make wool cards and pins and manufactured products such as hooks, cages, chains and traps. In 1568 Elizabeth I, keen to reduce English dependence on foreign goods, granted a patent to William Humfrey who, with William Cecil, had set up the first British wireworks in Tintern, Monmouthshire. They made iron and possibly brass wire for use in the wool industry, and for nails, pins, knitting needles and fish hooks. Later, the invention of the ‘wortle plate’ introduced the drawing of wire through a perforated metal plate; the holes were punched into the plate at a forge and could be heat treated and re-sized when they became worn.
High tensile steel wire was invented by the Victorians. In 1852, James Horsfall patented an isothermal lead bath quenching process that strengthened wire for producing needles, fish hooks and umbrella frames; with this process, he captured the whole global supply of piano wire. Later, with Joseph Webster in 1866, he manufactured some 30,000 miles of armoured wire for the first transatlantic telegraph cable.
- there are some 15 ferrous (iron and steel) wire drawing and cable-making sites in the UK;
- they produce around 160,000 tonnes of wire every year;
- about 52,000 tonnes is exported, to other European countries and beyond.