Steel is an alloy of iron and carbon containing less than 2% carbon and 1% manganese and small amounts of silicon, phosphorus, sulphur and oxygen. Steel is the world's most important engineering and construction material. It is used in every aspect of our lives; in cars and construction products, refrigerators and washing machines, cargo ships and surgical scalpels.
Integrated (blast furnace and basic oxygen furnace).Electric arc furnace (EAF). The integrated route uses raw materials (that is, iron ore, limestone and coke) and scrap to create steel. The EAF method uses scrap as its principal input.
The EAF method is much easier and faster since it only requires scrap steel. Recycled steel is introduced into a furnace and re-melted along with some other additions to produce the end product. Steel can be produced by other methods such as open hearth. However, the amount of steel produced by these methods decreases every year.
Steel is not a single product. There are more than 3,500 different grades of steel with many different physical, chemical, and environmental properties. Approximately 75% of modern steels have been developed in the past 20 years. If the Eiffel Tower were to be rebuilt today, the engineers would only need one-third of the steel that was originally used. Modern cars are built with new steels that are stronger but up to 35% lighter than in the past.
Steel is very friendly to the environment. It is completely recyclable, possesses great durability, and, compared to other materials, requires relatively low amounts of energy to produce. Innovative lightweight steel construction (such as in automobile and rail vehicle construction) help to save energy and resources. The steel industry has made immense efforts to limit environmental pollution in the last decades. Energy consumption and carbon dioxide emissions have decreased to half of what they were in the 1960s. Dust emissions have been reduced by even more.
Yes, very easily. Steel's unique magnetic properties make it an easy material to recover from the waste stream to be recycled. The properties of steel remain unchanged no matter how many times the steel is recycled. The electric arc furnace (EAF) method of steel production can use exclusively recycled steel. Steel is the world's most recycled material.
It is not known who produced the first steel. Since 200 BC, many cultures have produced steel in one form or another. A British inventor, Henry Bessemer, is generally credited with the invention of the first technique to mass produce steel in the mid 1850s. Steel is still produced using technology based on the Bessemer Process of blowing air through molten pig iron to oxidise the material and separate impurities.
Many elements and materials go through chemical reactions with other elements. When steel comes into contact with water and oxygen there is a chemical reaction and the steel begins to revert to its original form - iron oxide. In most modern steel applications this problem is easily overcome by coating. Many different coating materials can be applied to steel. Paint is used to coat cars and enamel is used on refrigerators and other domestic appliances. In other cases, elements such as nickel and chromium are added to make stainless steel, which can help prevent rust.