Carbon dating formula wikipedia
Certain compositions of cast iron, while retaining the economies of melting and casting, can be heat treated after casting to make malleable iron or ductile iron objects.
Steel is distinguishable from wrought iron (now largely obsolete), which may contain a small amount of carbon but large amounts of slag.
These qualities include such things as the hardness, quenching behavior, need for annealing, tempering behavior, yield strength, and tensile strength of the resulting steel.
The increase in steel's strength compared to pure iron is only possible by reducing iron's ductility.
Common alloying elements include: manganese, nickel, chromium, molybdenum, boron, titanium, vanadium, tungsten, cobalt, and niobium.
This process, known as smelting, was first applied to metals with lower melting points, such as tin, which melts at about 250 °C (482 °F), and copper, which melts at about 1,100 °C (2,010 °F), and the combination, bronze, which has a melting point lower than 1,083 °C (1,981 °F).
In comparison, cast iron melts at about 1,375 °C (2,507 °F).
Too little carbon content leaves (pure) iron quite soft, ductile, and weak.
Carbon contents higher than those of steel make a brittle alloy commonly called pig iron.
Iron is commonly found in the Earth's crust in the form of an ore, usually an iron oxide, such as magnetite or hematite.