How a Steel Mill Works
How A Steel Mill Works
The principal consumables employed in steel production are iron ore, coal, scrap metal and electrical energy. The importance of each of these consumables depends upon the technological processes adopted at each mill. In a classic integrated mill, coal and iron ore are the main consumables.
In semi-integrated mills, scrap iron is the mainstay.
An integrated mill comprises four basic operations – reduction, refining, solidification, and rolling – to convert iron ore into semi-finished or finished (rolled) steel products.
• Reduction The objective is to convert iron ore – naturally occurring in the form of ferrous oxide – into pig iron.
In this operation, a coker converts coal into coke that is then combined with iron ore in a blast furnace to produce molten pig iron.
• Refining Converting pig iron into steel is called refining.
The most common technology is the basic oxygen furnace (BOF) which injects oxygen into the molten metal to adjust the carbon content and reduce contaminants such as sulfur, nitrogen, and oxygen. Alloying elements needed to obtain desired chemical and mechanical properties are also added during refining.
• Solidification The most widely employed method of solidification is continuous casting, developed in the
1950s to replace conventional ingot casting.
• Rolling This final phase of integrated production converts semi-finished products such as slabs, blooms, and billets into finished products.
In addition to iron ore and coal, integrated mills use limestone in blast furnaces and oxygen in converters.
Semi-integrated mills operate in three phases – refining, solidification, and rolling – by using scrap iron as the basic feedstock. At these mills, liquefaction of the metallic charge is carried out in electric arc furnaces with electricity as the main energy source. Since scrap iron already contains carbon, there is no need to add carbon by using coal or coke, eliminating the need for
The principal consumables employed in steel production are iron ore, coal, scrap metal and electrical energy. The importance of each of these consumables depends upon the technological processes adopted at each mill. In a classic integrated mill, coal and iron ore are the main consumables.
In semi-integrated mills, scrap iron is the mainstay.
An integrated mill comprises four basic operations – reduction, refining, solidification, and rolling – to convert iron ore into semi-finished or finished (rolled) steel products.
• Reduction The objective is to convert iron ore – naturally occurring in the form of ferrous oxide – into pig iron.
In this operation, a coker converts coal into coke that is then combined with iron ore in a blast furnace to produce molten pig iron.
• Refining Converting pig iron into steel is called refining.
The most common technology is the basic oxygen furnace (BOF) which injects oxygen into the molten metal to adjust the carbon content and reduce contaminants such as sulfur, nitrogen, and oxygen. Alloying elements needed to obtain desired chemical and mechanical properties are also added during refining.
• Solidification The most widely employed method of solidification is continuous casting, developed in the
1950s to replace conventional ingot casting.
• Rolling This final phase of integrated production converts semi-finished products such as slabs, blooms, and billets into finished products.
In addition to iron ore and coal, integrated mills use limestone in blast furnaces and oxygen in converters.
Semi-integrated mills operate in three phases – refining, solidification, and rolling – by using scrap iron as the basic feedstock. At these mills, liquefaction of the metallic charge is carried out in electric arc furnaces with electricity as the main energy source. Since scrap iron already contains carbon, there is no need to add carbon by using coal or coke, eliminating the need for