Steel cord consists of extremely fine steel wires twisted together into a structure that is exceptionally strong yet flexible. Used mainly to reinforce radial tyres, it has travelled a long way from blacksmiths’ workshops to high-tech production lines. 1. Origins: the age of simple wires. Before steel cord, tyres were reinforced with natural fibres such as cotton and later nylon. As vehicles became heavier and road speeds increased, these fibres were no longer adequate. In the 1920s, the first efforts began to use single-strand steel bead wire to prevent tyres from slipping off their rims. 2. Michelin and the radial revolution (1946). A turning point in steel cord history is associated with Michelin. In 1946, the company introduced the first radial tyre with steel layers. This required steel with very high tensile strength and resistance to fatigue caused by continual tyre rotation. The concept of steel cord as a multilayer strand was born. 3. Metallurgical evolution: brass coating. Bonding steel to rubber was one of the greatest historical challenges. Bare steel does not adhere to rubber and rusts in moisture. Scientists found that an extremely thin brass coating—copper and zinc—on steel wires creates a chemical reaction during vulcanisation that bonds steel and rubber. This technology was perfected in the 1950s and 1960s. 4. The 1970s and 1980s: thinner, stronger, lighter. The 1970s fuel crisis prompted vehicle manufacturers to reduce weight. Steel cord production moved towards wires less than 0.15 mm in diameter. High-carbon steel enabled thinner strands with tensile strength exceeding 2,500 MPa. 5. Steel cord today: nanotechnology and sustainability. Production has entered a new phase: corrosion resistance through new compounds preventing moisture penetration into the tyre core; environmentally friendly steel cord through the removal of toxic compounds from brass plating and the use of recycled steel; and open-cord structures that allow liquid rubber to penetrate fully between wires and prevent internal friction. Conclusion: Steel cord is now the skeleton of the tyre industry. Racing bicycles and giant mining trucks alike depend on these steel strands. Progress in its manufacture directly means greater road safety and lower fuel consumption.