Pig iron
Cast iron is the product of the blast furnace process.
Properties
The pig iron has a high carbon content of about 4 to 5%, up to 3 % silicon and up to 6 % manganese, and also small amounts of sulfur and phosphorus. This accompanying elements make pig iron is cold very brittle, it is neither malleable ( rollable ) still weldable.
Cast iron may have a gray or white fracture face. Outweighs the silicon content, cast iron will arise after cooling, which has a gray fracture surface. Outweighs the effectiveness of manganese, combines with the cooling in the pig iron, the carbon with the iron to form iron carbide. This results in a radiating, white fracture surface (white metal). The product is used after solidification as Temperrohguss is prepared from which, by a heat treatment (annealing ) of malleable.
Processing
Grey cast iron must be directly processed into finished products during the casting process, as it is too brittle for further processing after the first cooling.
White cast iron is, however, further processed in the converter process to steel.
Where ( injection of oxygen, electrochemical transformation), the excess carbon and the other contaminants from the pig iron is partially / entirely removed in various ways.
Pig iron is poured at Hochofenabstich in refractory lining ladle or torpedo cars. After transport to the steel plant, the excess carbon is burned in the converter by blowing oxygen, the pig iron is converted into crude steel. The heating caused by the combustion is offset by the addition of scrap. The resulting crude steel is then transferred from the still liquid state by continuous casting or ingot casting in the solid phase. At high silicon content of carbon is deposited on cooling in the pig iron as graphite from. The fracture surface appears gray ( gray cast iron ).
States with the largest funding
The most important by far Manufacturers land for pig iron is the People's Republic of China, followed by Japan and Russia. In Europe, the major producers Ukraine, Germany and France.