History and Development of Steel
– Steel has a long history, being made in India and Sri Lanka over 2,500 years ago.
– Initially, steel was expensive and used for making swords and knives.
– In the Middle Ages, steel production was limited due to lengthy processes.
– In the 17th century, steel production began in England and improved over time.
– The Bessemer converter and Siemens-Martin open-hearth process were significant advancements in making cheap steel.
Steel Production Process
– The basic-oxygen process is the most common method for making steel today.
– The process involves pouring pig iron into a large vessel called a converter.
– Scrap metal is added to balance the heat, and oxygen is blown into the iron.
– The excess carbon and impurities are burned off, and the desired carbon content is achieved.
– The resulting liquid steel can be cast into molds or rolled into various products like sheets, beams, and railway tracks.
Uses and Recycling of Steel
– Steel is a versatile and inexpensive material used in various applications.
– It is commonly used in constructing buildings, bridges, and machines.
– The majority of ships and cars are made from steel.
– When steel objects become old or irreparable, they can be recycled by melting them down.
– Steel is a recyclable material, allowing for its reuse in new objects.
Chemistry of Steel
– Steel is an alloy composed of iron and often carbon.
– Atoms in materials determine their properties, and the addition of carbon strengthens steel.
– Adjusting the carbon content alters the hardness, bending ability, ductility, magnetic properties, and corrosion resistance of steel.
– Higher carbon content makes steel harder but also more brittle.
– Steel properties can be modified by adding other elements like boron, manganese, chromium, nickel, molybdenum, tungsten, and cobalt.
Types of Steel
– There are numerous types of steel, each with varying chemical compositions.
– Undesirable elements like phosphorus and sulfur are minimized during steel production.
– Plain carbon steels consist of iron, carbon, and undesired elements.
– Different carbon levels yield steels with different properties, such as low-cost options for shipbuilding and harder steels for shears and machine tools.
– Alloy steels include additional elements like boron, manganese, chromium, nickel, molybdenum, tungsten, and cobalt, providing specific properties like rust resistance or increased hardness.Sources: https://simple.wikipedia.org/wiki/Steel
