The Steel Refining Process

Bessemer Converter

The transformation of steel

Steel starts out as multiple raw materials, it goes through mixing and melting processes until it finds itself in a ladle approaching a blast furnace. This furnace will convert the product into liquid steel. Steel is iron which has had most of the impurities removed. It is consistent in concentration of carbon throughout its structure. Impurities such as silica, phosphorous and sulfur have the ability to weaken the strength of the steel significantly so they must be completely removed. The main advantage of steel over iron is that of the highly improved strength.

Fire up the furnace

An open hearth furnace is one way to create steel. It is heated to about sixteen hundred degrees in order to separate the limestone and ore slag. These materials float to the surface. When the carbon content has reached the correct content, you have created carbon steel.

The Bessemer Process

The Bessemer process involves oxidation of the impurities in the ?¢‚ǨÀúpig iron?¢‚Ǩ‚Ñ¢. This is accomplished by blowing hot air through the molten iron in a ?¢‚ǨÀúBessemer converter?¢‚Ǩ‚Ñ¢. The heat of the oxidation process raises the temperature and keeps the iron molten. During this process, impurities unite with the oxygen and this forms oxides. Carbon monoxide burns off and the other impurities form slag.

The oxygen furnace

Modern steel plants now use an oxygen furnace to create steel. The main advantage to this is the speed of the process. It is ten times faster than that of the open hearth furnace. High purity oxygen blows through the molten iron, lowering carbon, silicon, manganese and phosphorus levels. Fluxes are added in order to reduce sulfur and phosphorus levels. At this point, alloys can be created by mixing other metals with the refined steel. An example of that is the addition of chromium and molybdenum to create chrome-moly steel, a substance that is not only strong but also quite light.