Steel is a combination of various metallic components formed by mixing in alloys with iron. The amount of alloys blended with the iron will ultimately determine the characteristics of the produced steel since alloys act as hardening agents. Various types of alloying elements can be utilized in conjunction with iron to produce steel. These are tungsten, manganese chromium, vanadium and carbon. The latter has proven to be the more cost efficient alloying agent and is thus largely favored by steel manufacturing plants.
1. Perform the direct reduction process to extract iron from crude mineral ores.
There is no such thing as pure iron existing in nature. Iron will always be bonded with other elements such as oxygen. Since this is the case, the direct reduction process has to be performed to subject these crude mineral ores to purification. Although there are specific varying techniques in reduction, the common objective of such processes is to remove oxygen to finally extract iron. Direct reduction furnaces burn the ores in extremely high temperatures. Once the ores are sufficiently heated, carbon monoxide and hydrogen are infused to flush out the oxygen content producing Directly Reduced Iron (DRI).
2. Process the Directly Reduced Iron (DRI) to manufacture molten steel and slag.
Modern plants manufacturing steel use the Electric Arc Furnace (EAF) for this purpose. Extremely high voltage arcs of electricity come out of the large electrodes of an EAF and produce heat intense enough to melt DRI. The electrodes are slowly lowered into the furnace loaded with DRI. As it does so, the voltage is also slowly increased. There are two products that result from this procedure. One is steel which settles in the bottom of the EAF and the other is slag which is actually made up of various oxidized metals and floats on top of the molten steel. Slag contains the impurities, the compounds that need to be further taken out of the DRI in order to turn it into steel. The molten steel is tested for quality, its temperature and chemical composition is measured and evaluated. Once the correct grade is achieved, the slag is poured out from the top and the molten steel is tapped out from the bottom.
3. Produce semi-finished forms of the steel.
Various industries use steel in different ways. How the molten steel will be molded into its solidified form largely depends on which industry is being supplied. The term used to refer to these semi-finished molds of steel is billet. One method that steel plants employ to mold steel is called continuous casting. In this technique the molten steel is fed through large rollers while being simultaneously doused with cold water. The machine used for continuous casting can be configured to produce various shapes and sizes of steel billets.
Although light weight materials such as aluminum and plastic are cheaper to produce and can thus be supplied in greater quantity, steel's unique resilience and other favorable properties still makes its production necessary. In heavy industry, no other material has been invented yet to replace steel in the central role it plays.