How steel is made
How steel is made Being strong, cheap and versatile, steel is one of the most widely used metals in the modern world and the second most mass-produced commodity after cement. Steel has built railways, skyscrapers, oil and gas pipelines, bridges, automobiles, ships, cutlery, razors and surgical instruments. From a tiny screw to the Eiffel Tower, steel is everywhere! Steel production has taken place for almost 4,000 years, the beginning of the Iron Age. Pieces of ironware have been excavated from an archaeological site in Anatolia, modern Turkey, dating back to 1800 BC. The Roman military used steel and the ancient Chinese used it to make pillars for pagodas. In simple terms, steel is an alloy of iron and carbon but can also contain small quantities of phosphorus, silicon, sulphur and oxygen. Iron is found in the Earth's crust in the form of an ore. It is extracted from iron ore by removing the oxygen, a process, known as smelting. Iron ore and coal used in the UK is imported, as the UK's resources are limited and not economically viable. They arrive in very large ships and are off-loaded at deep-water harbours near the four steelworks that use it; in Teesside and Scunthorpe and Port Talbot. To produce steel, iron ore is heated and melted in furnaces. Impurities are extracted and carbon added. A simple definition of steel is "iron alloyed with carbon, normally less than 1%." Most steel is made using one of these processes: • Blast furnace • Electric Arc Furnace (EAF) Blast furnaces tend to use raw materials (iron ore, limestone and coke) whereas Electric Arc Furnaces use mainly scrap steel. Steel has a unique balance of flexibility, hardness and tensile strength. Other materials are often added to produce steel with applicable properties. For example, chromium increases hardness and melting temperature; nickel and manganese add to its tensile strength and vanadium also increases hardness but at the same time makes it less prone to metal fatigue. There are over 3,500 different grades of steel with many different chemical, physical and environmental properties. Steel facilities used to make ingots from the raw cast iron product which would be stored until it was needed for further processes that resulted in the finished product. In modern steel plants, it is continuously cast into long slabs, cut and shaped into bars and extrusions and then heat treated to produce a final product. Only 4% is produced as ingots these days. Recent economic booms in China and India have led to a huge increase in the demand for steel. Between 2000 and 2005, the world demand for steel increased by 6%. Since 2000, several Indian and Chinese steel companies have risen to prominence like Tata Steel (which bought Corus Group, previously British Steel, in 2007). World crude steel production reached 1,665 million metric tonnes in 2014, up from 1,606 million metric tonnes the previous year. Steel requires relatively little energy to produce and is completely recyclable. Due to modernisation and improved practices, energy consumption and carbon dioxide emissions are less than half than in the 1960s. It is therefore very environmentally friendly and sustainable.