Steel

**Steel Composition and Properties**:
– Steel contains 0.02% to 2.14% carbon by weight.
– Alloy steel includes intentional alloying elements like manganese, nickel, and chromium.
– Steel has improved strength and fracture resistance compared to iron.
– Various elements like chromium and nickel are added to modify steel’s properties.
– Steel can be heat-treated to enhance its properties.
– Pure iron exists in BCC alpha iron structure at room temperature.
– Carbon can form cementite when it moves out of solution with iron.
– Different metallurgical structures form in steel based on carbon and iron concentrations.
– Steel density ranges between 7,750 and 8,050kg/m^3 or 7.75 and 8.05g/cm^3.
– Heat treating processes for steel include annealing, quenching, and tempering.

**Steel Production and Recycling**:
– Iron is commonly found in the Earth’s crust as an ore.
– Iron is extracted through smelting, where oxygen is removed.
– Impurities are removed from pig iron to produce steel.
– Steel production involves reducing carbon content in smelted iron.
– Various elements are added to steel to achieve desired properties.
– Steel is one of the most recycled materials globally.
– In the United States in 2008, over 82,000,000 metric tons of steel were recycled, with an overall rate of 83%.
– Recycled raw materials account for about 40% of the total steel produced.
– Steel production exceeds the amount that is scrapped.
– Steel’s recyclability contributes to its sustainability.

**Historical Evolution of Steel**:
– Steel production dates back to antiquity with bloomeries and crucibles.
– Steel was produced in Celtic Europe from 800BC and in Britain from 490-375BC.
– High-carbon steel was produced in the Netherlands from the 2nd-4th centuries AD.
– Evidence of early high carbon steel production in South Asia.
– Wootz steel known for its durability and global exportation.
– Introduction of Henry Bessemer’s steelmaking process in 1855.
– Development of the Gilchrist-Thomas process to remove phosphorus.
– Siemens-Martin process as a complement to the Bessemer process.
– Use of electric arc furnaces (EAF) for reprocessing scrap metal and pig iron into new steel.
– Bethlehem Steel in Pennsylvania was one of the world’s largest steel manufacturers before closing in 2003.

**Steel Industry and Global Impact**:
– The steel industry contributes 8% of global greenhouse gas emissions.
– Major steel producers include ArcelorMittal, Tata Steel, Baosteel Group.
– Increase in global steel demand due to economic growth in China and India.
– Steel is one of the most commonly manufactured materials worldwide.
– China is the top steel producer with one-third of the world share.
– Ranking of other major steel producers like Japan, Russia, and the United States.
– Significant carbon dioxide emissions associated with steel production.
– Downturn in the steel industry at the end of 2008.
– Global greenhouse gas emissions attributed to the steel industry in 2021.

**Types of Steel and Applications**:
– Stainless steel contains at least 11% chromium for corrosion resistance.
– Carbon steel makes up 90% of steel production.
– High strength low alloy steel provides additional strength at a modest price increase.
– Advanced High Strength Steel (AHSS) is a new variety meeting CAFE regulations.
– Stainless steels resist corrosion with added elements like chromium and vanadium.
– Tool steels are alloyed for maximum solution hardening.
– Steel is widely used in construction, infrastructure, appliances, and buildings.
– Major structures like stadiums and skyscrapers are supported by steel skeletons.
– Steel is used in car bodies, shipbuilding, aerospace, and white goods.
– Applications include reinforcing concrete, mining, and office furniture.https://en.wikipedia.org/wiki/Steel